Mercedes-Benz caused a sensation with the presentation of these two vehicles at the 1954 International Motor Sports Show in New York. Specialists and the general public alike were enthusiastic. The 300 SL was presented for the first time as a series-production sports car (W 198 series), the famous “Gullwing” coupé. The totally newly-designed 190 SL (W 121 series) presented by the company as a roadster, created just as powerful an impact. This first-generation SL sports cars already allowed one to envisage the brilliant future that lay ahead of these attractive and innovative production vehicles with motor sport abbreviations in their designation.

Based on the legendary Gullwing coupé, the open 300 SL Roadster (W 198 II), which was built in parallel with the 190 SL, was launched in 1957. The body form of the two-seater open car was thus defined as the typical characteristic of the SL family. The 300 SL and the 190 SL together prefigured numerous features of later SL generations and both were thus the forerunners of all the SL series that followed.

In 1963 the SL, W 113 series arrived on the scene; it was dubbed the “Pagoda SL” because of the characteristic shape of its hardtop roof. It was followed in 1971 by the R 107 series that achieved the highest production volume of all SL series to date because of its long production life of 18 years. In March 1989 Mercedes-Benz introduced the R 129 series. Featuring numerous technical innovations, this car carried the SL-Class over into the new millennium. After a production period of twelve years and two facelifts it was replaced in 2001 by the R 230 series – the first one with a steel folding top. Finally, in the spring of 2012 the R 231 series is due to be launched as the next generation of the Mercedes-Benz SL-Class.

Source: Daimler AG

It was an eventful era that ushered in groundbreaking technical developments for the evolution of the automobile. In this period the automobile became an important mode of transport and powerful item of sports equipment, new plants were set up, and in 1926 the Daimler-Motoren-Gesellschaft from Stuttgart merged with Benz & Cie. from Mannheim to create Daimler-Benz AG, thus giving rise to the Mercedes-Benz brand. But these decades also bore witness to the First World War and the Great Depression, along with the massive blaze that engulfed the Daimler plant in Cannstatt.

This era must actually have left behind a wealth of documentary records. And yet anyone looking in the mid-1930s for a central location where documents would cast light on the former Daimler-Benz in this period would be sadly disappointed. Clearly nobody was really aware of the historical potential of documents from daily operations. Since Carl Benz and Gottlieb Daimler changed individual mobility forever with their Patent Motor Car and motorised cab in 1886, many documents had simply been lost – a fact Max Rauck quickly realised while completing the preparatory research for setting up the archive. In September 1935 the engineer reported to the Board of Management that there was “only very little historical material [...] in our company”. Meanwhile, the company’s employees still failed to appreciate the importance of the archive: in response to a circular dated March 1935, the engineer received “only a handful of historical material”.

In the company there was a realisation early on that innovation arose particularly against the background of tradition. In 1899, Daimler not only showcased the latest models at the Paris Automobile Salon but also the motorised cab from 1886 – visitors of the day viewed the 13-year-old vehicle as a bizarre classic vehicle, with the new automobiles worlds apart from the comparatively simple technology in their forerunner.
A key milestone in this analysis of the product history through exhibits comes in the shape of the museum work, which began back in the days of DMG in Untertürkheim. But only with the inauguration in 1936 of the first Mercedes-Benz Museum open to the public does the museum become an integral part of the public perception of the brand and company.

A new culture of document management
The gaps in the material for the fledgling archive collection essentially related to documents. For instance, the Daimler-Motoren-Gesellschaft decided in November 1924 to destroy almost without exception the contents of its archives that covered the period from the company’s foundation through to January 1919. The decision may have been taken for entirely practical reasons: in May 1924, DMG founded a community of interests with Benz & Cie., which was an important step along the way to the merger in 1926. Against the backdrop of this new cooperation, DMG at the time no longer believed their old archive material from the period before the First World War important enough to transfer to a new, joint archive.

Nonetheless, two copy books belonging to Gottlieb Daimler and Max Duttenhofer were retained, along with vehicle records, order books and engine books. Rauck also turned up historical letters as well as newspapers and magazines. A copy book was an accounts book – required under law at the time in Germany – that was used to enter business correspondence. Other periodicals existed in the plant library – in total these printed sources went back to the year 1898. The collection of photographs (“some in albums, some collected loosely, unfortunately with no details of the type of the object or the year of construction”) and catalogues as well as operating instructions (“unfortunately not complete”) nonetheless also formed a sound base.

By contrast, the material found at Benz & Cie was extremely sparse: “I didn’t manage to find any historical material whatsoever on the company Benz”, Rauck reported back to the Board of Management, “even though apparently all the historical documentation is supposed to have been transferred to Untertürkheim when the companies merged in 1926.” Where the material ended up is uncertain. In any case no historical documents whatsoever were left at the Mannheim plant – despite the budding archivist asking on several occasions.
The search for documentation of the company’s own history therefore proved a challenge. One exception came in the shape of the patents filed by Daimler-Benz AG and its predecessor organisations: “The Patent Department has kept all the old patents”, Rauck reported in his letter to the Board of Management in 1935. The oldest patents filed by Daimler and Benz, virtually the birth certificates of the automobile, currently form part of the archive, while the Patent Department still looks after collecting all the other historical patent documents. And further successes were also reported in 1935: Rauck described the photo archive taken over from Berlin-Marienfelde as “very interesting and complete”, and he got back from Berlin a file believed to have been lost that included old newspaper reports about Benz & Cie.

In summer 2011, UNESCO underscored just how visionary preserving the patents from the early days of the company’s history actually was: Carl Benz’s patent document from 1886 for a “vehicle with gas-engine drive” together with a bundle of other documents on the invention of the automobile were added to the World Document Heritage on 15 July. This accolade is not just testimony to the unique importance of these documents, but also to Daimler’s ongoing archival work.

The go-ahead for the archive
The Daimler-Benz AG Board of Management decided shortly after receiving the report to turn the project of a corporate archive into reality. As such, Daimler-Benz AG was following the lead taken by large German corporations such as Krupp and Siemens. The historical archive of Friedrich Krupp AG was regarded in its day as the most important industrial archive in Germany, having been founded in 1905. The Siemens archive followed in 1907. These models would be the benchmark used in Stuttgart in the future: “Anyone wanting to look seriously at the history of the automobile and engines will need our historical archive”, was the conclusion of a report drawn up shortly after the archive was founded, which compared the archives maintained by Krupp and Siemens with the new Daimler-Benz archive.

The issuance of administrative order number 1145 dated 9 December 1936 is regarded as the official foundation date of the Daimler archive. Yet the planning and preliminary work started earlier, with Rauck’s research dating back to early 1935. And on 16 September 1935, Rauck was commissioned to start systematically documenting the existing material, at the instance of Board member Wilhelm Kissel.

A space “in which all historical material (photos, written works, printed papers, etc.) should be preserved” – the idea was to open up the archive in the winter of 1935/36. As early as 1935, senior management stressed that the history of the entire Group including all its locations should be documented centrally: “This measure is naturally not only limited to the Untertürkheim plant, but extends to the other Group plants.”

A start was made on setting up the archive by searching for existing historical material on the one hand and setting up an infrastructure to hand over important documentation from current daily business on the other. This second aspect also lay at the heart of administrative order no. 1145 dated 9 December 1936, which is regarded as the official foundation date of the corporate archive. The order, which was made public by means of notices and circulars to the departmental heads, read:

“We have commissioned Mr Max Rauck Dipl.-Ing. to collect and sort through our historical written and pictorial material in order to set up and manage a historical archive, and hereby order that all our company’s locations assist Mr Rauck in carrying out the said task and, in particular, point out at their own initiative any existing material in their working area and provide him with appropriate access. Mr Rauck is entitled to add any pictorial and written works, provided these no longer have any current practical value, to the archive he is about to set up.”

The importance of the archive for Daimler AG is also manifest in the current “Group policy on the corporate archive”. Similar to the administrative order from 1936, the policy sets out at Board of Management level for all companies and employees of the Daimler Group worldwide that the corporate archive as Daimler AG’s memory fulfils all tasks of archive management and has a guideline function for Group-wide uniform standards when taking over, evaluating, opening up and preserving archive material. The policy expressly emphasises that the tasks of the archive extend equally to digital and analogue documents and information, thus ensuring proper archiving for the present and future.

In 1937, the archive presented its organisational plan in which the importance of collaboration between individual locations was once again highlighted: it was “urgently required to make all plants within the Group aware of the extraordinary value of the historical central archive and to ask them to preserve all material of historical value and to transfer the material to the historical central archive when requested to do so”.

Organisationally the archive unit was assigned to the Exhibitions department, which was also responsible for representing the company at motor shows as well as for designing exhibition spaces at sales and service outlets, and dealers. The tasks of the associated unit, the “Historical Area”, were set out in an internal report dated 20 October 1937 and included “setting up and continuing the archive, collecting and supporting hist[orical] objects and documents belonging to the Group, preparing lit[erary] work in this connection, museum issues, managing the historical material”.

Assess and preserve
The archive’s organisational plan from the same year proved visionary: the aim was to collect a wide range of documents, with a minimum time lag between origination of the documents and collection. In this way, the collected material on a certain vehicle model, for instance, was kept constantly up-to-date by continually adding new documents instead of waiting for all the relevant documents to be compiled after the end of the production period.

Here, the archive had already laid the foundations for the subsequently established practice of managing the collections on the basis of relevance and affinity: according to the key topic addressed in the individual files. The documents that were constantly being added to the archive were therefore assigned to the material according to topic. The corporate archive deviates from this principle primarily in the case of complete archived material, such as material sourced from individuals. One prime example is the Béla Barényi collection: the pioneer of modern vehicle safety donated his private archive to the corporate archive in 1990. This archive alone contains some 200 folders on the history of passive and active safety in the passenger car.

There was, however, still a long way to go from those first few years after its foundation before the well-oiled machine of the modern-day archive was in place. In 1937 a great deal of work was done on honing the structure used to organise the archive. Wilhelm Kissel, who was appointed the Chairman of the Daimler-Benz AG Board of Management in October 1937, himself set out his requirements for the archive structure. Talking to Max Rauck, Kissel emphasised the need for “a structure based on years”, within which the documentation on each individual year should be structured according to various topics: annual reports, leading personalities, photographs, written material, brochures, sport and exhibitions. By December 1937, more than 600 collected volumes and printed matter had been added to the archive under this model.
From the outset, the staff in the corporate archive rose to the classic challenge of their profession: they had to identify with vision what was ready for and worthy of inclusion in the archive. The benchmark is not solely how important documents are at present – the archivists also constantly have to try to judge what the documentation might mean from the perspective of future generations.

Collecting material without any selection process was not an option – if only due to space constraints. In the winter of 1937 the Archive reported to Wilhelm Kissel, who had now been appointed Chairman of the Board of Management, that “the space available [...][had been] entirely filled and it [would be] [...] highly desirable and necessary for additional rooms to be made available for the historical central archive in order to process and house the material that continues to be generated”.

As such, the contents and size of the archive grew, housed at the time in the so-called canteen building on the plant site in Untertürkheim. The storage facilities were also changed: in addition to the wooden cupboards used in the first few years, in 1939 an order was placed with August Blödner, Spezialfabrik für Stahlmöbel und Eisenbau (a company specialising in steel furniture and ironwork) based in Gotha for “double-walled, two-door fireproof cupboards”. As early as August 1935, Kissel had suggested this type of storage for irreplaceable documentary material. However, there was still not enough space to evaluate and archive all the collated material at a central location. Hence, the Archive proposed erecting a new building, with modern equipment throughout, including air conditioning, carbon dioxide extinguishing system and metallic archiving system.

Moved to the hen house
Yet a totally different fate would befall the archived materials in the Second World War. Instead of being relocated to a new building, they were moved from the Untertürkheim plant. On 8 April 1941 a note stated that, among other things, the most important documents from the founding years had been stored in a bank safe.

During the war a large part of the archive was moved to Kühbach (Aichach-Friedberg district) in Bavaria. Under the code name “hen house”, Daimler-Benz AG stored “various records, books, copies of drawings” as well as a variety of equipment in the cellar of the brewery on the Baron von Beck estate. Following the end of the war, the US Third Army, in whose area of responsibility the archive was being stored, was hesitant to allow the material to be taken away. The company initially rented external archive premises in Esslingen while the Untertürkheim plant was being reconstructed and civilian series production was being slowly ramped up. It was only in 1948 that the archive returned to the Untertürkheim site.

The period of the German economic miracle is not only an era of change and productivity for automobile production but also for the archive: in 1954 it became an independent department, reporting directly to the Board of Management department “Central Management”. This period also gave rise to numerous important publications on the history of Daimler-Benz AG’s products and the company itself, as well as on the history of the automobile and technology in general.

Archive and museum under a single roof
1957 saw the archive and museum being combined, bringing together the product and document collections, and generating numerous synergies in the process. This structure has been retained to the present day. The merger was reflected particularly in the inauguration of the Mercedes-Benz Museum on the plant site, with the new building being completed in 1960 and inaugurated in 1961: the archive was housed in the same building. When the new Mercedes-Benz Museum was opened off the plant site at Mercedes-Benz World in 2006, the archive moved into the building directly opposite the plant gates located on the Cannstatt side.
The archive’s organisational structure also changed over the years. The current system was set up in 1973: at the time, the decision was taken to “extend the document base to the non-technical area”, to split up the hitherto “mainly technically oriented” historical archive into the technical archive and corporate archive. The archives still retain the same structure even today: apart from the corporate archive and the product archive, there is the media archive, archive library and the vehicle collection.

Economic and social history
The corporate archive preserves documents and artefacts relating to individuals and the company’s history. These include sources on the company founders, the complete company history and the development of the plants, as well as the Board members with reports on Board of Management and Supervisory Board meetings. Documents detailing sales of in-house products and on investments form part of the corporate archive along with press kits and a art collection including rare posters, original graphics and designs for advertising motifs as well as the advertising collection including advertisements dating back to 1885. The racing archive documents the motorsport involvement of Daimler and the predecessor companies from the first race in 1894, through the Silver Arrows era in the 1930s and 1950s to the present-day competitors. And the archived material also includes documents on the social history as well as artefacts ranging from coins, medals and trophies through to promotional items.

Technical expertise in its historical context
The product archive documents the history of passenger cars and commercial vehicles since the invention of the automobile by Carl Benz and Gottlieb Daimler. The archived materials include brochures, price lists, owner’s manuals, workshop and parts literature along with technical reports and design drawings. The original vehicle records, order books and engine books, which document the as-delivered condition of virtually all passenger cars ever built by the Daimler, Mercedes and Mercedes-Benz brands provide a treasure trove of information. Added to which are vehicle data cards for over 10 million passenger cars from the period 1945 to 1985.

These documents also constitute important sources for Mercedes-Benz Classic that allow the manufacturer to produce expert reports: based on this historical information and a technical diagnosis, the experts from Mercedes-Benz Classic can verify and document the originality of valuable Mercedes-Benz vehicles.

Open to new media
The media archive includes some three million photographs from the early years of automotive construction to the present day. This includes almost 300,000 historical black-and-white negatives, almost a third of which are large-format glass negatives. The media archive also features some 4000 films along with the audio collection comprising original interviews with contemporary witnesses and other contributions to oral history.
The media are accessible in an extensive database, which facilitates rapid search and distribution. The corporate archive also embraced the digital future early on: the data in the archives has been processed electronically since the early 1990s. In 2000, the M@RS database (Multimedia, Archive and Research System) also went live on the internet. M@RS is not an island solution limited to the archives but was always designed from the outset as a cross-departmental solution that could be deployed throughout the Group to provide all types of media and documents.

Meanwhile M@RS is being used in the Group by more than 20 other clients, with data constantly being added; for the archives this integrated solution has the major advantage of providing up-to-date data such as product and marketing information early on to ensure long-term availability.

This willingness to embrace new media is nothing new: back in April 1938, Max Rauck noted: “We have to set up a sound archive. [... W[e] already have various wax discs, f[or] e[xample] “Dr Nibel talks about the racing car” etc. You could also find stories from old Daimler and Benz veterans on wax discs.” In the same year, Rauck also suggested they should also archive historical film material. As such, the archive was consistently geared to a variety of media from the moment it was founded.

Literature on vehicle technology and the automotive industry
The archive library is a large reference library that specialises in automotive technology and the automotive industry. In addition to the numerous works on the Mercedes-Benz brand as well as on Daimler AG and its predecessor companies, there are also extensive archives on general automotive and technology history. The almost complete edition of the “Allgemeine Automobil-Zeitung”, a car magazine first published in 1900, is a remarkable rarity on the international library scene. The library also holds other publications from the early days of the automobile. In total, the library contains some 10,000 books, and 220 magazines, of which 90 are current titles. The library’s collections also include numerous books published by the Archive itself. This publication work on brand-specific topics as well as on basic issues relating to automobile history boasts a long tradition in the archive.

History on wheels
The Mercedes-Benz Classic vehicle collection forms the basis for all automotive activities linked to the unique tradition of Mercedes-Benz.

A company-owned vehicle collection has been documented in the archives since 1921. The collection consists of more than 900 vehicles, some 160 of which are on display as exhibits in the Mercedes-Benz Museum. Other vehicles are on show at exhibitions and motor shows, or used at new vehicle presentations, at classic car events and rallies. A binding collection concept governs the way in which the vehicle collection is expanded and managed. In this way, the brand’s groundbreaking products are collected according to set criteria and preserved for posterity – according to precisely the same discerning requirements that the historical archive has fulfilled since 1936.

Source: Daimler AG

The archive, one of the largest business archives anywhere in Europe and undoubtedly the most complete in the automotive industry, provides a documentary record of the outstanding history of the company, its products and ideas dating back to the invention of the automobile in 1886. Its contents are testimony to the ability to develop visionary designs, and document a varied economic and social history.

“The archives underpin our unique corporate history with information on all the products that we have built over the past 125 years since Carl Benz and Gottlieb Daimler invented the automobile”, says Michael Bock, Head of Mercedes-Benz Classic and Managing Director of Mercedes-Benz Museum GmbH. “We utilise this virtually inexhaustible source mainly for Mercedes-Benz brand communications.”

Officially the archives’ history began 75 years ago with administrative order no. 1145 from the then Daimler-Benz Aktiengesellschaft. On 9 December 1936, the company’s Board of Management stated in the order that the engineer Max Rauck had been commissioned “to collect and sort through our historical written and pictorial material in order to set up and manage a historical archive”. However, Rauck had already been exploring in-house the wealth of material worth archiving for nearly two years on behalf of the Board of Management.

The archives have constantly grown since administrative order no. 1145 was published, with their structure and focus being continually honed. Throughout this process, Daimler has taken note of the overall media, political and economic background, but above all focused on the company’s development itself.

Key milestones in the archives’ history include the structural merger with the museum collection in 1957, the relocation to the then newly built Mercedes-Benz Museum in 1960, and the historical archive being split in 1973 into the technical archive and corporate archive. Today the Group’s memory comprises the corporate archive, product archive, media archive and archive library as well as the vehicle collection.

Today the archive faces the increasingly important task of collating and preserving sources from various media types. This challenge is also being used productively by rolling out tools that provide users with multimedia access to the archived content. This applies particularly to the multimedia, archive and research system M@RS.

Source: Daimler AG

“This is a very comprehensive reference work,” says Michael Bock, Head of Mercedes-Benz Classic and Managing Director of the Mercedes-Benz Museum. “Günter Engelen spent seven years researching his book and was able to draw on seven decades of knowledge and experience in covering the important role played by competition vehicles in over almost 125 years of automotive history.”
The book features the entire range of racing and sports cars built by Mercedes-Benz and its predecessor brands and used in motorsport from 1894 onwards. The author describes cars from every era, beginning with the very early years, and depicts in impressive detail the company’s approaches to racing car development and competitive success. The book features not only the most celebrated vehicles but also pays special attention to those mentioned only fleetingly in previously published works, such as the rally and off-road sports cars of the 1920s and 30s.

The eras following the Second World War are also given comprehensive treatment, beginning with the brand’s return to motorsport in 1952 and the Mercedes-Benz 300 SL racing sport coupé. The author gives a detailed account of the background and development of the early post-war Silver Arrows from the 1954 and 1955 seasons. He also provides an interesting and rare insight into the rally vehicles used before 1980. We are brought into the modern era with chapters covering DTM vehicles, the record-breaking drives of the C 111, Group C and GT motor racing, before our attention is turned to an analysis of the Silver Arrows from the most recent history of Formula One and finally the Mercedes-Benz SLS AMG GT3 race car. The book concludes with a list of brief biographies of the main personalities and developers.

As a comprehensive and fact-filled compendium covering the entire spectrum of Mercedes-Benz racing cars and sports cars, this new reference work is unique. The author approaches each vehicle with expert knowledge and clarity, using a combination of precise texts, many previously unpublished photographs and detailed tables of technical data.

Born in 1938, Günter Engelen has been working as a journalist specialising in automotive history since 1985, and in particular in the vehicle history and development of Mercedes-Benz passenger cars and commercial vehicles. As a contributor to many specialist periodicals he has had numerous articles published. He is also the author of several other books on the Mercedes-Benz brand, which have attracted a wide readership for the wealth of information and narrative history they convey.

Source: Daimler AG

At that time it bore the name Mercedes-Benz Maybach. But the time of its market launch five years later, Maybach had been revived as a brand in its own right. The study, that had been created in Daimler-Benz’s Japanese design studio, was the result of extensive investigations which had been carried out amongst the intended customer group all over the world.

Some of the study’s most impressive characteristics included fully reclining seats, a bar and communication system in the rear, a luminescent band in the body at waistline height as a new design feature, a body made of sophisticated lightweight construction materials, headlamps with electronic light distribution, electro­chromic glass in the roof with colouration irrespective of sunlight, three telephone systems on board, touch-sensitive screens, suspension with Active Body Control (ABC) and a V12 engine with cylinder shut-off.

The Maybach (240 series) was be classified as a follow-on vehicle within the ‘Super Mercedes’ tradition. It presented what was technically possible and created a new benchmark for superlative-class cars.
Two Maybach models were unveiled as series-production vehicles; in July 2002 came the Maybach 62 – whose model designation was derived from its overall length, which measured 6.2 metres (to be precise: 6165 millimetres) – which offered a similar amount of space as earlier Pullman saloons. This was followed in October 2002 by the Maybach 57 (which had an overall length of 5728 millimetres).

For years the Maybach 62’s USPs included the two reclining seats in the rear and the optionally available panoramic sunroof with its electrotransparent glass and solar cells for operating the rear air conditioning when stationary, plus – making its maiden appearance in the Maybach 62 – the ability to make the roof transparent or darken it at the touch of a button. In the second of these modes 76 per cent of the incidental light was still let through. Apart from this particular roof, a conventional roof with or without a solar module, a tilting/sliding sunroof for the rear compartment with an upstream solar module and a tilting/sliding sunroof without a solar module were also available.

The glass window in the optional partition between the front and rear seats was also equipped with the electrotransparency familiar from the panoramic roof.

The reclining seats offered six different adjustment functions: head restraints’ length, height and inclination, backrest inclination up to 47 degrees, fore/aft adjustment up to 135 millimetres; length and inclination of the lower-leg support and footrest angle adjustment.

The automatic seat belts with belt tensioners, belt-force limiters and sidebags were housed in the backrest as an integral restraint system. In addition to the sidebags, the passengers were also protected by four windowbags in case of a crash. As an option the seats were available with the multicontour backrest.

The front and rear windows consisted of 6.2-millimetre-thick laminated glass, with 7.2-millimetre-thick side windows. A special film facilitated effective noise insulation through its sound-deflection properties. The grey-tinted glass filtered the UV rays and reflected the infrared light from solar radiation. This brought a 27.5-per-cent advantage over green-tinted glass for the front windows – 22 per cent for the side windows – where infrared reflection was concerned.

For climate control two completely independent systems were available.

The Maybach 57 was developed primarily for the owner-driver who appreciates a generous sense of spaciousness but does not neces­sarily require all the space provided by a vehicle that is more likely to be in the chauffeur-driven category. For this reason, up until April 2010 the multi-adjustable reclining seat was exclusively reserved for the Maybach 62.

The other technological features beneath the bodywork were the same for both models: they came in the form of the 405 kW (550 hp) V12 engine, which offered a superb torque of 900 newton metres between 2300 and 3000 rpm and transferred this power to the rear axle via an automatic five-speed transmission.
The chassis with its double-wishbone suspension at the front and the multi-link independent rear suspension was fitted with the full-support self-levelling semi-active air suspension system AIRMATIC DC. The front brake discs (with a diameter of 376 milli­metres) were gripped by two four-piston disc brakes, whilst at the rear one four-piston disc brake calliper sufficed for the 355-milli­me­tre discs.

The 275/50 R 19 tyres were worn on 8 J x 19 forged light-alloy wheels.

The modestly shaped body had an excellent cd value for such a majestic saloon: 0.31.

The testers’ opinions on the Maybach’s ride comfort and handling were unequivocal. Writing in 2002, journalist Götz Leyrer of ‘auto motor und sport’ described his impressions: ‘So as was once the case with the 600, the Maybach demonstrates convincingly what Mercedes technicians are capable of if they are let off the tight leash of cost optimisation. Ride comfort is just world-class, even creating a clear lead over the S-Class. Gently cradling, the Maybach makes the condition of the road irrelevant. The noise from the powerful tyres is reduced to a minimum.

And in 2003, Bernd Stegemann wrote in ‘auto motor und sport’s detailed test report: ‘But who will quarrel about trivialities when they are being carried through the stresses of everyday life with incomparable serenity and gentleness? There is no doubt that the comfort experience in the Maybach deserves to be rated “excellent” and again puts a proper distance between it and the S-Class. It is no one individual achievement, not space, not silence nor the comfort of the seats alone that differentiates it from the norm, but the harmonious interplay of all the factors. If there is such a thing as tangible added value, a justification for the existence for this type of car: here it is.

When it came to the interior design, testers from the Swiss ‘Automobil Revue’ had the following impression when performing a comparative test with the Rolls-Royce ‘[...] Kitsch does not prevail in either of them, but in the Swabian there is so much well-done swank in the form of the popular wood/leather steering wheel, chromed trim strips, lavish Alcantara trim and sumptuous wool panelling.

At the 75th Geneva Motor Show in March 2005 Maybach unveiled the 57 S model, to date the car with the most active driving style in the superlative segment. The enhanced V12 engine came from subsidiary AMG, which had developed this unit for the powerful special models from Mercedes-Benz. In order to increase the engine output, it was not simply a case of raising the charge pressure: the entire engine was modified and its displacement increased from 5.5 litres to 6 litres.

With the simultaneous revision and adjustment of the turbochargers and charge-air coolers, the output could now be raised to 450 kW (612 hp), the torque from 900 to 1000 newton metres. During the course of this increase in output, the suspension was also adjusted. The S model was given 275/45 R 20 tyres which were worn on special 8.5 J x 20 forged light-alloy wheel rims.

For the occasion of the International Auto Show in Detroit in January 2007, the majestic 62 model was also bestowed with the more powerful S equipment. Particularly for the long-wheelbase version, which after all weighed a good 155 kilograms more, it was not just the higher engine output that constituted a major comfort factor for an ambitious yet relaxed driving style – the higher torque was significant too.

Following on from the S models with both wheelbases, at the Geneva Motor Show in 2009 the new top versions celebrated their debut under the name Maybach Zeppelin – this was a limited edition of 100 units. For owners with an active driving style, they were characterised – with a nice historical nod to the top model of its day, the Zeppelin – by the 471 kW (640 hp), 1000-newton-metre engine, which was the most powerful Maybach engine in a passenger car to date. The ‘Zeppelin’ lettering beneath the Maybach emblem with its double-M discreetly drew attention to the most powerful and most expensive passenger car of this exclusive range. There was, however, no historical link to this logo – it was a totally new creation. The Maybach for connoisseurs was full of visual highlights that set it apart: two-tone body paintwork, and high-quality leather with diamond-pattern upholstery in the interior, discreet ‘Maybach Zeppelin’ logos and trim in high-gloss piano lacquer completed the look. In the interior the perfume atomiser was a major new feature, releasing an individual fragrance.

At the 2010 Auto China trade show in Beijing Maybach unveiled its revised models, whose exterior differs from the previous models through the more upright position for its radiator grille. The grille on the S models now has six vertical chrome rods on each side. The centre rod is wider and appears to be an integral part of the grille frame. The front apron was given modified air intakes and daytime running lamps with LED technology. At the tail end, the new generation is signalled by dark red tail lights and chrome panels running transversely above the bumper. A new feature also includes the option available to buyers of the 57 and 57 S models to select one of the rear reclining seats, which is then installed on the front-passenger side in the rear. The seats now have a different look, which is characterised by additional piping in the centre seat and backrest section. As an option, a hand-woven version of the piping is available, with four fine, individual leather strips or with valuable CrystallizedTM Swarovski Elements.

Also as an option, all models are now available with a perfume atomiser which was developed exclusively by Maybach, and which had previously only been available for the Zeppelin special model. This equipment detail is a very special highlight. At the press of a button it produces a unique fragrant experience in the interior, through the use of sophisticated technology and fine scent. At the heart of the system lies a plexiglass sphere illuminated from within to which the Maybach owner can add a flacon containing their own personally selected perfume. A compressor sends a gentle flow of air into the plexiglass sphere and fans perfume molecules from the flacon into the car’s interior.

As an optional extra, the vehicles are available with a partition featuring a 19-inch screen and an overview camera. This enables the passengers in the rear to observe the traffic even through the non-transparent partition. Internet access comes courtesy of a WLAN router.

Although the engine output for the S models was raised to 463 kW (630 hp), carbon dioxide emissions are down from 390 to 368 grams per kilometre. And for the other models with 405 kW (550 hp) the carbon dioxide emissions have also been cut: from 383 to 350 grams per kilometre.

Source: Daimler AG

‘By unveiling the “Super Mercedes” Model 600, Daimler-Benz AG is presenting the vehicle that belongs in the top international league and that has time and again been the subject of discussion in Germany and abroad for many years. Mercedes-Benz is creating a link with the company’s pre-war tradition of being present in the world’s small group of outstanding representative vehicles – in the form of a luxuriously appointed car which offers the highest degree of handling safety.

The company explicitly pointed out that this was not a matter of an existing model being replaced, but that a grand pre-war tradition of famous, large, representative vehicles was being picked up. And the sumptuous brochure which was produced for the launch of the Model 600 also headlined with ‘The Super Mercedes’.

‘One approaches the large black car with awkward timidity. From its external aspect there is no doubt that this is a Mercedes-Benz. Powerful and heavy and perfected right down to the last detail it stands on its huge 9.00 x 15 tyres. And it is scarcely the grandeur of its appearance that really stops one in one’s tracks. Quite simply: it is the knowledge that one is looking at the best, most interesting, most advanced car there has ever been.’ Heinz-Ulrich Wieselmann, editor-in-chief of ‘auto motor und sport’ was not given to such euphoric assessments. The Berlin-born journalist with a loose tongue and a critical pen had not yet had the last word. The talented driver with a penchant for the upper speed echelons described the handling of the vehicle – which weighed in at some three tonnes – as follows: ‘We spoke of the driving characteristics of the “Super Mercedes” with a decidedly sporty driving style and we would expressly like to describe it as excellent. Not a few car manufacturers would give a lot to see their little racers moving through the bends as fast, as effortlessly and as safely as this three-tonner. Ride comfort is absolutely unrivalled.

Head of Passenger Car Design Rudolf Uhlenhaut decided on three main points of focus for a superior, up-to-date representative vehicle back then: maximum passenger comfort, maximum safety and superb performance.

These were basically also the premises under which the predecessor model was developed before the war, but this is often forgotten, in view of the political climate in which many of the vehicles of the time were operating.

The range of bodies available reflected a change in insight amongst those who used representative vehicles from the exclusive segment. In the case of the ‘Super Mercedes’ prior to the Second World War, the emphasis was putting individual people on display, which was reflected in the proportion – 67 per cent – of the total number of vehicles built. After the war this self-promotion aspect, which had above all been popular amongst dictators, increasingly faded into the background as democratic conditions became established. The proportion of open-top vehicles with a landaulet design was only 22 per cent in the post-war period where the ‘Super Mercedes’ was concerned. Only the landaulet on a long wheelbase existed as an open body form of the Model 600, with the exception of a landaulet with a short-wheelbase which was made for Count Berckheim. No cabriolets were built.

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Head of Press Arthur Keser invited ten European journalists to Val de Poix in Belgium on 28 August 1963 in order to present the new ‘Super Mercedes’ to them. They were Robert Braunschweig, Bernard Cahier, Piero Casucci, Paul Frère, Hermann Harster, Jacques Ickx, Harry Mundy, Hans Patleich, Heinz-Ulrich Wieselmann and Gordon Wilkins. The Daimler-Benz delegation welcoming them consisted of Fritz Nallinger Rudolf Uhlenhaut, Josef Müller, Karl Wilfert and Arthur Keser. In his introductory talk Uhlenhaut explained the developmental focal points of a superior-class car whose development had begun eight years previously.

Keser was highly satisfied with the response to the presentation. After all, Robert Braunschweig from Bern had made no secret of his opinion when he announced that he had never expected Daimler-Benz to succeed in launching such a car right away. And Briton Harry Mundy explained that for years he had been trying in vain to persuade Rolls-Royce to modernise their vehicles. But they had not heeded his warnings, and now Rolls-Royce had to face up to the fact that Daimler-Benz was bringing to market a car which far exceeded Rolls-Royce’s standards.

In mid-1955, Nallinger laid down the key data of assembly C as the basis for the vehicle, detailing them as follows: ‘This assembly stands for the large touring and representative cars of the future. Its standard specification includes an automatic transmission, power-assisted steering and power-assisted brakes. It has the usual 6 seats. The floor assembly has been designed in such a way that a vehicle with 3 seat rows could also be created by extending the wheelbase if applicable.

Although Nallinger was already speaking in visionary terms in February 1956 of an eight-cylinder all-alloy engine with a displace­ment of 6 litres, development of the first V8 engine (M 100) for a Mercedes-Benz passenger car began with a displacement of 5 litres. The first specimen was running on the test station by the end of 1959. In two further stages the displacement was increased within a relatively short period of time to 5.8 litres and 6 litres to 6.33 litres in the end, with a final output of 250 hp (183 kW). A crucial factor here was the vehicle’s overall weight, which was repeatedly adjusted upwards during the course of development due to the extended host of equipment. In the case of the first three displacement sizes there were light-alloy crankcases with grey cast iron bushes. For the increase in displacement to 6.33 litres a crankcase made of grey cast iron was necessary, in order to accommodate the bore, which was 3 millimetres larger. In the four-speed automatic transmission the planetary gear set was extended from three to six planetary gears in order to transmit the considerably higher torque.

An interesting and noteworthy anecdote from a historical perspective concerns the fact that in 1956 chief engineer Nallinger was planning to include a V12 engine with a 7.5 litre displacement, deeming it to be a fitting partner for underlining the image of such a large touring and representative car. The installation drawings by engine designer Adolf Wente in 1957 proved that this was more than just a question of ideas being played around with. The 6.4 litre and 6.7 litre V8 engines from Cadillac and Chrysler were a decisive influence on Nallinger’s considerations.

By the end of the 1950s, it no longer sufficed for a ‘Super Mercedes’ to have a large body or display good performance in order to have a USP. More was expected of a Mercedes-Benz. The challenge that company employees in Untertürkheim and Sindelfingen set them­selves was practically to make the impossible possible. Werner Breitschwerdt said of the Model 600 when looking back at the end of the 1980s: ‘In those days then we wanted to build a car that could do everything that was possible, and it had to be capable of doing more than all the other cars – for the driver and the front passenger.’ This culminated in concrete demands for ride comfort of the highest calibre unrivalled to this day, and at the same time sporty driving characteristics, a large car and yet playful handling and a luxury vehicle but athletic performance.

The operating comfort was exemplary for the time, because in Sindelfingen they refused to be satisfied with the usual electrically aided assistance functions for the window lift mechanisms or the door strikers. In a competition between electric assistance systems developed by Werner Breitschwerdt and a hydraulic system designed by Ernst Fiala, the latter won the day. Breitschwerdt commented on the matter as follows: ‘The electrical system would not have been able to accommodate the many functions that we wanted to incorporate back then. The problem was space and weight, because, amongst other things, we would have needed a second battery. The advantage of the high-pressure hydraulics system that had been developed was that precisely because of its high pressures it was able to get by with small elements. The hydraulics system was simply smaller, quieter and lighter than electrical systems that existed in those days.

Many parts were specially developed in Sindelfingen, as similar components from the aviation industry proved to be too heavy. The convenience hydraulics system supported or completed these functions: locking the doors (extended central locking); operating the sliding sunroof, operating the windows, operating the partition, operating the boot, operating the heater and vent flaps, front and rear seat adjustment, shock absorber adjustment and release of the parking brake.

A particular focus during development of the new ‘Super Mercedes’ under Uhlenhaut’s leadership was on combining comfort with safe, sporty handling. The amalgamation of the air suspension with the front wishbones and the single-joint swing axle with additional lowered thrust arms with braking torque support and two cross struts and double suspension in conjunction with the adjustable shock absorbers resulted in euphoric reviews for the driving characteristics. In 1965 Reinhard Seiffert wrote of the ride comfort in the ‘Motor Revue’: ‘Ride comfort which undoubtedly optimises everything previously attained in automotive technology has been achieved.’ And of the handling safety: ‘The over-used word “adhesion” is entirely appropriate here, for the handling is completely neutral and remains so during fast cornering – up to a stage when at the rear there is perhaps somewhat less lateral stability than at the front, so that a slight decline in the wonderfully direct and sensitive steering allows safe control of the vehicle. But this is definitely not the norm. One can drive the 600 like a sports car on mountain passes without experiencing such phenomena – a well-driven sports car will then have trouble keeping up.

And in the end there is in actual fact nothing more and nothing less than the best car in the world, which is the conclusion drawn by the American magazine ‘Car and Driver’ following a comparison test also involving Cadillac and Rolls-Royce models, and as Reinhard Seiffert sums up with ironic understatement in ‘auto motor und sport’ in his test in 1966: ‘That one can – even when assessing cars – use such a vehicle as a point of orientation is a ray of hope in view of the general trend towards mediocrity. It is by no means exaggerated to expect from all cars as much comfort and operability as the 600 offers. They can probably never be too good, as even the 600 is, as we discovered following three weeks of everyday use, is just about good enough.

The engineers took particular care over the braking system. At the front and rear the ‘Super Mercedes’ of the post-war period had dual-circuit disc brakes, with two brake callipers for each of the front 291-millimetre discs. The 9.00 x 15 diagonal tyres were specially designed for the Model 600 by the tyre manufacturers Fulda and Continental.

Right from the outset the saloon bodies were available with the usual wheelbase of 3200 millimetres, the Pullman saloon with 3900 milli­metres. They were later joined by the landaulet and Pullman saloon body variants with six doors. Two special designs were the landaulet with a short wheelbase for Count Berckheim and the Pope’s vehicle, also a landaulet, but this time with a long wheelbase.

It was astonishing that the Model 600, as sharp-edged as it appeared, had a Cd value of 0.458. By way of comparison: the Model 230 SL with a hardtop had a cd value of 0.515 and a Model 190 SL with a hardtop a cd value of 0.461.

The M 100 engine was also used in the S-Class, first of all in the Mercedes-Benz 300 SEL 6.3 (W 108), with no change to the output. Then in 1975 the Model 450 SEL 6.9 (W 116) made its debut with an engine whose displacement had been brought up to 6.9 litres and which now developed 286 hp (210 kW). This stage of evolution was also tested in the Model 600 – there is known to have been one test vehicle –, but in its case its displacement remained at 6.3 litres until manufacturing finished.

With a production period of 18 years between 1963 and 1981, the Model 600, alongside the SL of the 107 model series, is one of the vehicles that was made for the longest amount of uninterrupted time at Mercedes-Benz. Production was divided up into the following units:

The USA was the largest customer, buying 743 vehicles.

Next came Germany with 589, France with 151 and Great Britain with 126.

The two-door coupé built in Sindelfingen in 1965 was a special case. It was intended to be a test vehicle for looking into the possibility of a large coupé, which had been on the agenda all along as a successor to the 300 Sc (W 188 II). Today this coupé is privately owned and remains a one-off.

Source: Daimler AG

There was also the fact that by then the entire range of passenger cars and racing cars – with the exception of the Nürburg model – had been changed over to designs which included front and rear independent suspension and that since 1931 when it built the Model 170, Mercedes-Benz had been a major protagonist in the arena of advanced passenger car chassis. Daimler-Benz was even already appearing on the international stage as a licensor for the progressive front suspension with two trapezoidal links and coil springs. Even the American motor industry, which tended to be more reserved in such matters, was now using this front suspension.

It was above all a challenge facing design boss Max Wagner: to come up with an up-to-date chassis for the new ‘Super Mercedes’, and the experience gained when redesigning the W 125 and W 154 racing cars proved valuable to him. As was the case with the latter models, for the new ‘Super Mercedes’ he used a chassis made of pipes as a longitudinal member. At the front axle this had trapezoidal links of unequal length and coil springs, and at the rear what was known as a parallel wheel axle – a DeDion axle with coil springs. The thrusts at the rear axle were absorbed by V-shaped front-facing members, which were pivoted on the centre transverse pipe.

The outer longitudinal members made of pipes were curved far downwards in front of the rear axle in order to achieve a low centre of gravity. The longitudinal members were connected to six transverse pipes which were pierced and welded with the longitudinal members. In conjunction with the large shock course for the spring, this torsionally rigid design with bending resistance resulted in excellent road holding, which was unusual amongst such big and heavy luxury cars. This was illustrated by a quotation from the only test report of the time, which appeared on 23 May 1939 in the British magazine ‘The Motor’: ‘Normally a limousine of this size will not be driven in a spectacular manner. We did some fast travelling on winding roads and the general standard of handling and road holding is undoubtedly very good indeed. The car holds its course admirably through fast bends, and the absolute rigidity of the tubular chassis is well reflected in the road holding. Although no ride control is employed, the suspension system provides a good combination of soft riding in town with steady cornering and freedom from excessive roll on the open road, and the whole car gives an impression of considerable stability.’

But it was not merely the chassis design that made such a difference compared with the predecessor – the larger dimensions played a part too. The wheelbase increased by 130 millimetres, the track width at the front increased by 100 millimetres, and at the rear by as much as 150 millimetres. And so the task of the body designers working under Hermann Ahrens was to create lighter, more spacious bodies, whose length grew by an extra 400 millimetres, making them precisely 6 metres long. But the vehicle weight also increased with the size. Whilst the brochure for model series W 07 still referred to 2700 kilograms, the weight for model series W 150 went up to between 3400 kilograms and 3600 kilograms – also according to the brochure. And in some cases it did not stop there. For the special-protection version as a six-seater, 4400 kilograms of mass had to be set in motion – as much as 4550 kilograms in the case of the even more heavily armoured four-seater.

The engine output was also increased for these weights. In the naturally aspirated version the engine output increased by 5 hp (3.7 kW) to 155 hp (114 kW), with a switched-on positive-displacement blower by 30 hp (22 kW) to 230 hp (169 kW). The shafts of the outlet valves were filled with sodium salt for better cooling.
The three-speed transmission from the predecessor with engageable overdrives did not survive in the successor either. It was superseded by a four-speed transmission with a fifth gear as a high-ratio overdrive.

So as not to be punished by shorter refuelling intervals with the increased engine output and significantly higher weights, the tank capacity went up from 120 litres to 195 litres. For what was the world’s largest representative vehicle when it entered the market Daimler-Benz gave the top speed as 170 km/h, though this was drastically cut to 80 km/h for the heavily armoured versions with their bullet-proof twenty-chamber tyres.

Superb performance
This is what ‘The Motor’ wrote about the performance and top speed of the conventional Pullman saloon in 1939:

‘Changing gear gently, without the second-saving brutality that has normally to be employed for test purposes, it proved possible to cover the standing quarter-mile in 21 seconds. From a standstill to 50 mph took 12.2 secs. and to 60 mph. 17 secs., which suggests the standard of performance available without necessarily indicating the absolute maximum results obtainable. Cutting the blower in for a quarter of a mile sufficed to raise the speed from 75 mph to 87 mph, demonstrating its value in maintaining high averages after temporary checks. Timed over a quarter of a mile, the car clocked 100 mph. With some ease, carrying four people; indeed, it was accelerating along the Railway Straight at Brooklands. The speedometer is very nearly accurate erring slightly on the side of slowness lower down the range, and the ultimate readings obtained suggest that the absolute maximum speed is in the region of 108 mph, a truly impressive velocity for an eight seater limousine weighing 3 tons.’

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The career of the ‘Super Mercedes’ (W 150) unarguably suffered due to the Second World War, which began shortly after production started. This was also borne out by the body variants produced: the open-top touring cars favoured by the government dominated, in stark contrast to the predecessor model, for which more civilian bodies had been made, such as cabriolets and Pullman saloons.

The bodies for the ‘Super Mercedes’ (W 150) were manufactured solely at the special vehicle production facility in Sindelfingen, which also met exclusive requirements. The designation ‘Sindelfingen body’ became a seal of approval in vehicle construction. The best-known example of this was the Cabriolet B, which was built as a one-off specimen for the heir to the Persian throne and is now a valuable item in the possession of an American collector.

Further special features included the various special-protection versions which existed in the familiar body forms, both open-top and closed. Vehicles with an armoured windscreen could be recognised by additional exterior slits which were linked up with the heating and ensured clear windscreens. Over the course of a special campaign during the war by order of the government calling for specially armoured vehicles (‘Aktion P’), ten four-door and four-window saloons were built. As has already been mentioned, they were even heavier than the special-protection Pullman saloons. Their windows were made of 40-millimetre multilayer glass. The floor was armoured with 8.8-millimetre plates, the rest of the body including the roof with 3.3-millimetre plates of special steel. One of those who carried out these modifications was Friedrich Geiger, who was to become the first Head of Design at Daimler-Benz in the 1950s. From the outside, only the very early vehicles could be told apart from the later models, due to their twin-row bumper and the absence of a boot flap. Their younger counterparts could be identified by the rubber-covered one-row bumpers, usually with two chromed bumper guards and a boot flap. The transition of the front wing to the running boards was non-uniform; sometimes it had a flowing design, but very often the wing was at an offset position to the running board.

In the case of the final special-protection cars built the running boards were left out altogether or concealed beneath trim, with the aim of preventing unwanted passengers from jumping onto the running boards. As was also the case decades later with the Model 600, particularly wide chromed window frames were an indication of especially thick window panes in a special-protection car. The doors were locked electromagnetically and the spare wheels used as an armoured shield. By way of compensation for the increase in weight, the wings were made of light alloy.

The new ‘Super Mercedes’ was the subject of a great deal of customer interest when it was launched – amongst authorities and civilian customers alike. However, because of the outbreak of war on 1 September 1939, only a few vehicles were delivered to civilians, as orders from the authorities were given priority. After the war the ‘Super Mercedes’ body served as a vehicle for heads of state, and was to be found in the royal fleets of Sweden and Norway, for instance, plus it was used when Winston Churchill visited the Norwegian King Haakon in Oslo in May 1948 and during the visit of Queen Elizabeth of England with Prince Philip in 1955.

The 1939 brochure showed the Pullman saloon, Cabriolet D, Cabriolet F and open-top touring car body variants.

The following bodies made up the 88 ‘Super Mercedes’ (W 150) produced between 1938 and 1943:

1 chassis (International Car and Motorcycle Show of 1938, Berlin) 1 Cabriolet B
5 Cabriolet D 7 Cabriolet F
46 open-top touring cars, some armoured 10 saloons, 4 doors, 4 windows, armoured
18 Pullman saloons, 4 doors, 6 windows, some armoured

A successor was developed for the model series W 150. In 1938, the model series W 148 had already been integrated into the development planning process, though at that time it was still intended to be a replacement for the Model 500 N (W 08). But during the course of the development period it increasingly took up the position of successor for the model series W 150. Chief engineer Fritz Nallinger believed that this made more sense, as he explained in April 1941, for instance.

The W 148 model series was intended to mark the creation of a more modern representative vehicle that equalled the ‘Super Mercedes’ of model series W 150. In those years modernity also meant ‘downsizing’, without having to relinquish space and comfort. These efforts were supported by the powerful 170 hp (125 kW) compact V12 M 148 engine, which was considerably shorter than the large-dimensioned eight-cylinder in-line engine M 150 that had previously been used in the W 150, and the M 08 eight-cylinder in-line engine of the Model 500 N. Engine designer Wilhelm Syring had employed an inventive design in order to keep the unit compact – one that had also been used by Maybach for his V12 engines: the crankshaft’s crank pins, which were located next to the main bearings fitted to the block, had only one crank web. The other one was integrated in the main bearing, which was what made the engine very short. By those days’ standards this V12 engine was positioned very far forward over the front axle, leaving sufficient room for the occupants whilst at the same time reducing the exterior dimensions.

Apart from the advantage where the amount of space available was concerned and the more modern technical concept with hemispherical combustion chambers, the M 148 also offered economic benefits.
It could be produced much less expensively than the large M 150 eight-cylinder in-line engine, as it was also used as a static engine but was manufactured in relatively large quantities and was increasingly replacing the M 08 engine as a current-generator drive system. Up until 1945, 3420 units were produced of the M 148 and the 6.5-litre M 173 derived from it, which was exclusively used for stationary applications.

Even though the wheelbase of the W 148 model series was 100 millimetres shorter than that of the W 150 model series and the overall length was no less than 170 millimetres shorter, it still had a representative appearance. Occupants would have enjoyed the same level of spaciousness as they did in the legendary ‘Super Mercedes’. It was also so impressive because of the unrivalled reputation of a V12 engine whose smooth running characteristics were never able to match those of an eight-cylinder in-line engine. Despite the more compact dimensions the W 148 model series was no lightweight, tipping the scales with a mass of 3210 kilograms, but it did still undercut the previous ‘Super Mercedes’ by nearly 400 kilograms. Having said that, as development progressed, the company was forced to do without the weight reduction. The government was demanding more and more special-protection versions, and these would also have made the W 148 model series heavier than originally planned. In turn this would then have necessitated a more powerful engine – though that would have been an easy task for the experienced engine technicians from Untertürkheim. The belt-driven supercharger version of the M 148 was already available in the form of the M 157, which had an output of 155 hp (114 kW) without supercharging, and 240 hp (176 kW) with it.

The W 148 model series was more than just a pilot project. Up until 1942, work commissioned by the government was carried out on two open-top touring cars and two Cabriolet B vehicles. There was evidence that five test cars with various bodies in Pullman saloon and Cabriolet F guise were built, but as the war continued work was stopped in 1942. One Pullman saloon survived the war in a camp in the Black Forest, but no-one knows exactly what happened to this interesting vehicle – presumably it was scrapped. The other cars were probably destroyed by bombs that fell in Untertürkheim and Sindelfingen during the war.

Source: Daimler AG

The Federal President and the Federal Chancellor initially used cars merely as a mode of transport – the Pullman saloons and cabriolets from the Mercedes-Benz, Horch and Maybach SW 38 brands from pre-war times; the Governing Mayor of Berlin, Luise Schröder, used a Model 170 V as her official car.

At first everyone at Daimler-Benz had other things to worry about than thinking about a remake or new design of the ‘Super Mercedes’. The overall economic situation was gloomy, characterised by the rapid collapse of the ruined Reichsmark. An improvement was only to come about with the currency reform and the introduction of the German Mark, but this did not happen until 20 June 1948. Wilhelm Haspel called a meeting on 22 December 1947 with the aim of discussing plans for a sports and representative car; for a time he was not Chairman of the Board of Management at Daimler AG due to denazification, and it was not until 1 January 1948 that he took on this position again. The aim of the meeting was to decide on a range of vehicles also suitable for export – even in such dark economic times, Haspel recognised the necessity for Mercedes-Benz cars with the appropriate charisma in the luxury segment: ‘But what is missing is a vehicle that gold-plates the name Mercedes-Benz again.

Another year and a half would pass, however, before Haspel’s ideas took shape on a more modest basis – in the period directly following the war, Central Europe had moved towards vehicles with a much smaller displacement. Initially priority was given to the Model 170 S (W 136 III, later W 136 IV), which Daimler-Benz brought out in 1949. Before the war it had originally been earmarked as the successor to the Model 170 V (W 136), and for two years it now assumed the role of the later S-Class in the Federal Republic of Germany in terms of price and social status. The two-seater Cabriolet A even became the country’s most expensive car. In 1951, the Model 220 (W 187) was launched, and it, too, was one of the S-Class’s forerunners.

Against this background, the Model 300 (W 186 II) which was unveiled at the same time was seen as a superlative-class car back then – something that was reflected in its price and performance as well as its appearance.

But in the meantime the development department took several approaches when it came to creating a vehicle that gold-plated the name Mercedes-Benz again. In order to keep costs and new invest­ments to a minimum in view of the difficulties involved in the procurement of machinery, existing stock was used up. Where the chassis and the bodies were concerned this meant the Model 230 (W 153) with the all-steel body from Daimler-Benz which had come out shortly before the war, plus the corresponding chassis with an X-type pipe with a wheelbase of 3050 millimetres. When it came to the engines the production units for the 2.6 litre M 159 engine had survived the bombings to such an extent that they could be built up again. This resulted in no less than 9004 units of this engine being produced between 1941 and 1944. Although originally intended for passenger cars, they were all installed in the 1.5-tonne L 301 model, which had carved out a career for itself as a small fire-fighting vehicle, and as a bucket-seat car. This engine had a hemispherical combustion chamber with V-shaped overhead valves, which were operated by the low-mounted camshaft via tappets.

The first deliberations regarding the construction of a more representative vehicle were made on the basis of this M 159 and the model series W 153. To begin with it was given the model series designation W 182 and was intended to have a displacement of 2.6 litres. In order to take into account the increasing vehicle weight, in 1949/1950 the engine was given a series of higher displacements in rapid succession: firstly 2.8 litres and finally 3.0 litres, with various model variant designations to match.

Tried-and-tested technology as the basis for development
The engine derived from the M 159 was known as the M 182, and whilst it still had a crankshaft with four bearings and a displace­ment of 2.6 litres, it already boasted a modified cylinder head with larger valves. This was where engine developer Wolf Dieter Bensinger fell back on a design list that had been put together as a stop-gap measure, and this resulted in the characteristic oblique contact surface between the cylinder head and the cylinder block for the engine which was now called the M 186 I and for the variant derived from it. It was in order to take over as many production machines as possible from the manufacturing of the M 159 on the one hand, and also to create room for larger valves in the cylinder head on the other, that Bensinger hit upon the idea of the oblique section, which provided the larger area that was needed.

Along with the increase in displacement the crankshaft was converted over from four to seven main bearings. This engine with the internal designation M 186 I still had overhead valves operated via tappets, but that changed with the advent of the M 186 II, which operated the valves via an overhead camshaft. It was not until a good year before the vehicle presentation at the International Motor Show in Frankfurt am Main (IAA) in 1951 that chief engineer Fritz Nallinger told his colleague Karl C. Müller: ‘The results of work involving the M 186/II engine with an overhead camshaft have now reached such a stage that this design can be described as promising. Therefore I would ask you only to firmly plan in the machines which are used for the 186/II design and to set aside the machines which are additionally needed for 186/I.

Somewhat confusingly, the engine described at the testing stage as the M 186 II was later given the designation M 186 I or just M 186. Meanwhile the first design of the Model 300 always bore the model series designation W 186 II.

On 27 March 1950, in a report about the Geneva Motor Show, Nallinger also informed his Board of Management colleagues about the development status of what was classified internally as the ‘Group B car’, the Model 300: ‘The cylinder volume has been increased to 3 l, the control shaft moved upwards into the head. This has resulted in the following advantages: better governing of the engine speeds with regard to valve control, so that engine speeds resulting in favourable valve-time cross sections are achieved with the steeply rising cam shape. This means that with the 3 l engine with the normal carburettor engine and intake manifold configurations 115 hp is achieved.

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For reasons of time Nallinger now suggested building the body using stampings from the Models 170 S (W 136 IV) and 230 (W 153) and other new stampings. A solution that the Head of Body Testing in Sindelfingen, Karl Wilfert, who always tended to go his own way, set out in a letter to Wilhelm Haspel himself. But Wilfert had not reckoned on the reaction of his Chairman of the Board of Management. Haspel always had a very determined opinion on vehicles – when it came to both style and technology. He was completely opposed to Wilfert’s proposal and sent him the following reply: ‘Where the matter of shape is concerned, I believe that – even if you have fallen in love with this change – you will not contradict me when I say that this resultant object has become disproportionate and therefore decidedly inelegant. In short, there is no sense in wanting to change and modernise to such an extent an object that was created from a different overall design; the result will be a bastard and one should not do such a thing.

Hermann Ahrens, who had actually been taken on again after the war by Haspel to work on body design for commercial vehicles, buses and coaches, was commissioned by him to design the body for the model series W 186 II. Ahrens achieved a good compromise between the taste of the predominantly conservatively oriented customers influenced by pre-war Mercedes-Benz design and the expectations of the customers in the initial post-war years, who demanded forms that flowed much more, headlamps integrated into the body and the absence of running boards on a luxury Mercedes-Benz.

In actual fact, the frame of the model series W 153 served as the basis, and its wheelbase – measuring 3050 millimetres – was also retained, but the frame was dimensioned in accordance with the much higher weight of the model series W 186 II. The wheel suspensions corresponded to the latest standard at Daimler-Benz: at the front there were wishbones and coil springs. At the rear a dual-joint swing axle was used, which was designed especially for high levels of ride and suspension comfort. In order to ensure handling safety and comfort with a full load, a torsion-bar suspension which was electrically engageable via the dashboard was installed.

A surprise came in the form of the newly designed three-litre M 186 engine with an overhead camshaft and 115 hp (85 kW) at 4600 rpm. With a maximum speed stopped in tests by specialist journals at 158 km/h (‘auto motor und sport’), 160 km/h (‘Automobil Revue’, Bern) and 164 km/h (‘Motor Rundschau’ and ‘The Autocar’) it is Germany’s fastest car up until the unveiling of the Model 300 S (W 188) in October 1951, the latter being nothing other than the sporty two-door variant of the Model 300.

Linking up with the tradition of the ‘Super Mercedes’
The new Mercedes-Benz 300 top model presented in 1951 was a representative vehicle by central European standards, but compared with vehicles available internationally it was not. But as a represen­ta­tive vehicle with the more modest claim characteristic of those years it did connect with the tradition of the ‘Super Mercedes’. It was unveiled as a four-door, six-windowed saloon and as a four-door cabriolet, which was described in the Daimler-Benz nomenclature as the Cabriolet D.

From December 1952 onwards, the range of optional equipment features was extended to include a sliding sunroof and from March 1953 a partition between the driver’s area and the passenger compartment. Federal President Theodor Heuss and Federal Chancellor Konrad Adenauer accepted and adopted it as their official vehicle – in common parlance the car was even referred to as the ‘Adenauer’ 300. Legend has it that during the presentation in 1951 Adenauer asked General Manager Wilhelm Haspel in his Rhineland dialect: ‘Haven’t you got anything bigger?’. All the same he had his official car taken to Moscow when he visited the city in 1955, was driven in it to the Kremlin for his meetings with Nikolai Bulganin and Nikita Khrushchev and confidently and convincingly represented the young Federal Republic of Germany during its period of development.

The Model 300 also became a status symbol amongst many VIPs in Germany and abroad, such as King Gustav Adolph of Sweden and actors Gary Cooper, Errol Flynn and Fernandel, whose real name was Fernand-Joseph Désiré Contadin. The most famous customer of all was Pope John XXIII, whose specially designed 300 d Landaulet was one of the best-known Model 300 vehicles. The American Presidents from Dwight D. Eisenhower to John F. Kennedy were also driven through cheering crowds in the open-top Mercedes-Benz 300.

Under the headline ‘Might in moderation’ the Bern-based ‘Automobil Revue’ noted: ‘The tradition-bound, if also more relaxed, lines and the MB 300’s more powerful radiator which only varies slightly from the previous version, make it easy to overestimate its dimensions, which are modest compared with those of American cars.’ The Swiss went on to comment: ‘Anyone who changes over to the ’ But also: ‘The 300 is following the tradition of most European companies, which very rarely oversize their engines.’

In 1952, Werner Oswald attested to the Model 300’s superlative international class in ‘auto motor und sport’, summing up thus: ‘The engine performs fantastically. It’s not just its power and output – its elasticity, its refinement and its smoothness are delightful too. It is every bit the equal of the American throttle engines where the latter properties are concerned. Finally we want express how pleased we are that the Mercedes 300 also marks the German car industry’s return to the world market with a top product. In Untertürkheim they can be rightly proud of the fact that in building the MB 300 they have succeeded right away in creating a truly top-grade specimen.

In its test no. 1467, the British journal ‘The Autocar’ wrote of the Mercedes-Benz Model 300: ‘There are very few saloon cars which are capable of a mean speed of over 100 mph, but to obtain this result on a five-six-seater saloon car with generous room for passengers and luggage, using an engine of three-litre capacity said to deliver only 114 bhp is a notable achievement. The suspension and handling qualities offer a combination of riding comfort, stability and safety which reaches the pinnacle of current achievement. The ride is soft enough for the most fastidious passenger, but is very damped, and there is no sensation of roll, even when travelling really fast over winding roads.

There is no noticeable tendency to understeer or oversteer; if forced to the limit, the rear end will begin to slide, but in a way which is instantly controllable by a flick of the wheel. The Type 300 of Mercedes-Benz is clearly a very strong competitor for the favour of the most discerning international buyers, to whom it will appeal because of its performance, detail finish and equipment. It maintains a high general level of excellence.

In 1951, the year it was launched, another 43 vehicles were built. The reason for the fact that the price for a vehicle without tyres was indicated was that in those days there were market prices for tyres and their price was stipulated on delivery.

The express mention of a heater might cause surprise, but back then this was not a standard feature of many vehicles – including those from other manufacturers – though it always was in the Model 300, for instance, even if it was expressly mentioned in the price list.

According to the price list dated December 1952, at that time there was also a sliding canvas sunroof available for 750 DM, and from March 1953 for 950 DM there was also a partition between the passenger compartment and the driver’s area.

The Mercedes-Benz 300 b (W 186 III)
In Untertürkheim they were very much aware of the high expecta­tions that were placed by the customers on a premium product like the Model 300, so work went on incessantly to perfect it. The fruits of these labours were presented at the Geneva Motor Show in 1954 in the form of the Mercedes-Benz 300 b (W 186 III).
The exterior identifying features of the Model 300 b were the bumper guards on the front and rear bumpers, which the previous Model 300 only had for its export version. The vent windows in the front doors symbolised major progress where ventilation was concerned. The chromed perforated wheel rims ensured better heat dissipation from the larger – now ribbed – brake drums, referred to back then as turbocooling. The driver was supported by a standard-specifica­tion vacuum brake aid – another new feature which had not been included in the previous Model 300.

The engine output was increased by 10 hp (7.4 kW) to 125 hp (92 kW) at 4500 rpm, which brought with it a consumption cut at the same time; ‘auto motor und sport’ records 17.3 litres over 100 kilometres for the Model 300, and for the Model 300 b 15.6 litres. Several measures were responsible for this. The increase in compression from 1 : 6.4 to 1 : 7.5 played a decisive role, as did the changeover from two Solex model 40 PBIC two-stage compound downdraught carburettors to two Solex model 32 PAJAT downdraught carburettors with two mixing chambers whose throttle valves open one after the other depending on the position of the accelerator. Further progress made by the new carburettor system also included the automatic choke, which provided a richer mixture for a cold start.

A lot of journalists from the motoring press also described the Model 300 b as being a ‘superlative’ vehicle (‘Motor-Rundschau’) or a ‘diplomat’s car’ (‘auto motor und sport’). The partition between the driver’s section and the passenger compartment which was available as an option for this model from 1955 onwards also befitted its status as a diplomat’s car.

The Mercedes-Benz 300 c (W 186 IV)
For the International Motor Show in Frankfurt in September 1955, the Model 300 was again brought closer in line with the model range of the times in technical terms, and became the Model 300 c (W 186 IV). From the exterior it could only be distinguished from the 300 b predecessor model by the larger rear window and the larger tyre size, 7.60 x 15. Along with the wider tyres there was also a changeover to wider wheel rims with size 5.5 K x 15 B, which were later also used for the Models 300 d (W 189) and 300 SL Roadster (W 198 II), but were not recognisable at first glance. The two most important changes concerned the chassis and the drive system. In the chassis a single-joint swing axle now also replaced the dual-joint swing axle for the largest passenger car model from Mercedes-Benz, ensuring better driving characteristics. The new feature in the drive system was the inclusion of the automatic Borg-Warner DG 150 M transmission with three gears as part of the standard specification. As the manual four-gear transmission was now only available optionally and with a deletion allowance, the Model 300 c was the first German passenger car that was only supplied with a manual transmission as an option. Above all it was chief engineer Fritz Nallinger and export boss Arnold Wychodil who drove forward the inclusion of the automatic transmission in the Model 300 with a view to the American market, and who did not wish to wait any longer for the completion of the company’ own automatic transmission, which would only come into use another six years later.

In June 1956, a sales information bulletin mentioned a long-wheel­base version of the Model 300 for the first time, though this was not reflected in the price lists. The body and wheelbase had been extended by 100 millimetres. By also moving the rear seats back 40 millimetres, the legroom had been boosted by 140 milli­metres. It was the German Federal Chancellor Konrad Adenauer who initiated this design. At the beginning of March 1956 chief engineer Nallinger told his Board of Management colleagues the following about the Model 300 c: ‘I have included the car with an extended wheelbase, as in the version we shall be delivering for Federal Chancellor Adenauer. I think that we could include this extended wheelbase from September. The car can then accordingly be offered for sale at a higher price than the usual sales price.

It was only a few months before the expiry of Model 300 c in July 1957 that a footnote in the price list valid from March 1957 mentions the extended-wheelbase version. There is no separate mention of this late addition to the product range in the model variant and production lists which were otherwise always meticulously updated. Production of the large cabriolets had already ceased in mid-1956.

The Cabriolet D was no longer listed as of price list no. 4 dated 3 May 1956, analogous to the end of production in June 1956.

The extended version (with a wheelbase of 3150 millimetres) of the Mercedes-Benz 300 c (W 186 IV) cost 3000 Deutschmarks according to price list no. 5 dated 1 March 1957.

The version with an extended wheelbase was not given a separate model variant designation.

The Mercedes-Benz Model 300 d (W 189)
The Model 300 received its most extensive revision in autumn 1957, resulting in a new model series designation, W 189. Not only did the longer wheelbase represent the standard dimensioning with immediate effect; the overall look of the vehicle had changed considerably: Hermann Ahrens turned his final passenger car design into reality. The tail end with the gently contoured side wings and the vertical tail light layout corresponded to those of the Model 220 coupé/cabriolet (W 180) and was given a larger boot. The front was also redesigned. The headlamps received trim rings projecting forwards in keeping with the style of the time. The rectangular fog lamps integrated into the wings formed a contrast to the round main headlamps.

Progress for the driver came in the form of the large rear window which extended over the entire width and was wrapped around the sides. In conjunction with the retractable side windows and thanks to a 30-per-cent increase in the overall window area this helped to create a totally new sense of light and space and a better all-round view. At the time this concept was referred to as the ‘pillarless full-vision body’.

With an eye to the American market the Model 300 d had very much been brought into line with the expectations regarding driving which existed there. Examples of this included the suspension tuning which differed considerably from that of the original Model 300 and was now designed for comfortable, relaxed cruising. This impression was underlined by the smoother but also more indirect manual steering and the power-assisted steering which was optionally available with the standard-specification automatic transmission. The three-gear automatic transmission enabled the car to stand still on a slope without rolling backwards. Plus, when gear ‘D’ was engaged the first gear could now also be activated at speeds below 40 km/h by fully depressing the accelerator (‘kickdown’). In the predecessor it had only been possible to shift down from third to second gear in this way.

Passengers’ wellbeing was enhanced by air conditioning from December 1958 onwards. Due to the additional charge that came with it, when the announcement about this new feature was made it was noted: ‘A cooling system has been developed for the 300. The gross price for this has been set at DM 3500. As this price hardly covers the material costs, a discount cannot be granted.

The engine output was increased from 125 hp (92 kW) to 160 hp (118 kW) through the introduction of indirect manifold injection, so as to compensate at least partially for the higher vehicle weight. The tank capacity of 72 litres, which had been regarded as very mediocre, was now raised to 79 litres.

Within the exclusive series of the Model 300 d there was a special feature in the form of three vehicles specially built in 1960 which differed significantly from the usual saloons: a landaulet delivered to the Vatican for Pope John XIII., a second landaulet from the company’s fleet which was loaned to the Federal government for state visits, and a saloon for the same purpose with a large sliding steel roof in the rear. These cars differed greatly from the normal vehicles of the model because of their wheelbase, which was extended from 3150 to 3600 millimetres. The overall length grew from 5190 to 5640 millimetres, the width from 1860 to 1995 milli­metres and the height from 1620 to 1720 millimetres. The car’s weight went up by 375 kilograms to 2365 kilograms.

Leather upholstery (680 DM) and power steering (only with an automatic transmission, 750 DM) were not included in the price list. The prices were quoted in circulars no. 25/57 dated 12 September 1957 and no. 40/58 of 3 March 1958.

According to circular no. 67/58 dated 1 December 1958 the air conditioning cost 3500 DM. And the Cabriolet D was not included in the price list either – with an automatic transmission it cost 37,000 DM and with a manual transmission 35,500 DM, according to circular no. 69/58 dated 15 December 1958.

In the mid-1950s, Daimler-Benz acknowledged that the Model 300’s era was coming to an end, so head engineer Fritz Nallinger initiated work on a new ‘Super Mercedes’ with the model series designation W 100. It was unveiled in 1963 as the Mercedes-Benz 600.

However, with the Model 300 the company had created a viable link between the Mercedes-Benz passenger cars, the Germany of the post-war period and young Federal Republic – both in terms of the vehicle’s proportions and the stylistic reorientation that occurred in the years following the war. A Model 300 d as a vehicle for the Pope in the Vatican’s fleet did not appear like an exotic foreign body – it looked as though it had always belonged there.

Source: Daimler AG

One can safely assume that it is precisely those circles which always consider that only the very latest in excellence are just about sufficient for their requirements will focus their interest on this model.’ That was the conclusion drawn by the editor of the renowned ‘Allgemeine Automobil-Zeitung’ (AAZ) in 1930 about the ‘Super Mercedes’ unveiled at the Paris Motor Show. This was the official name of the Mercedes-Benz Model 770.

Around the end of the 1920s, the time was ripe for Mercedes-Benz to set a new landmark in the premium car segment. The Model 630 was no longer in keeping with the times, and Daimler-Benz was in danger of losing its standing in the top car class in view of the Maybach 12 model with a V12 engine (7-litre displacement, 150 hp/110 kW) which was brought out at the end of 1929 by its competitor Maybach, and the Zeppelin 8 model presented at the Paris Show a year later (8-litre displacement, 200 hp/147 kW). However, because of the brand’s reputation and also its recent in-house experience, Daimler-Benz was very careful when it came to new technical features. In 1932, the specialist publication ‘Motor und Sport’ reported on this matter on the occasion of the ‘Super Mercedes’ test:

‘In contrast to the American view, which is in favour of the V-engine of the 12- or 16-cylinder type as far as representatives of this price category are concerned, they have remained remarkably sober in giving the Super Mercedes an eight-cylinder in-line engine. With a vehicle whose fundamental tendency is towards exclusivity to such a great extent they thought that any excursion into uncharted waters would be fatal. That is how the new design from Daimler-Benz came to be a happy avowal of traditional links.’

It is true that from a technical point of view, the ‘Super Mercedes’ – known internally as W 07 – did not constitute a great leap forward into the realm of new technologies. There was certainly much expecta­tion amongst the general public surrounding the Mercedes-Benz 170 (W 15) which came out a year later in 1931, with its advanced chassis including independent suspension. But despite its conserva­tive chassis design with front and rear rigid axles, the new top model surprised people with its clear handling as a result of skilful suspension tuning. ‘Motor und Sport’ proves revealing here, too:

‘The Super Mercedes is certainly a fast car. With its saloon body it achieves a speed of 150 km/h. This kind of output is seen as racing-driver speed in many circles.

We know of vehicles, even more recent ones, in which it would be reckless to drive at over 70 km/h, whereas there is no such limit where the Super Mercedes is concerned. In contrast to some statements made by the competition which have come to light, the conduct of the Super Mercedes at all speeds is beyond reproach. Whilst the car’s springing is not as sensitive as it is amongst the American competitors, the Super Mercedes enables a sure driving style that secures cohesion with the road. We do not know of any vehicle that would allow such safe driving with heavy bodies at the breathtaking speed of 120 km/h. And this is probably where the ultimate sense and the ultimate justification for the existence of this vehicle model are to be found. In spite of its orthodox fundamental philosophy, the Super Mercedes presents itself as the worthy conclusion of Daimler-Benz production and as the final enhancement of automotive comfort achievable with today’s means.’

The criticism of large cars’ handling was indeed an issue back then; on another occasion the testers found fault with the handling of the Cadillac V16 and Maybach 12, which were direct competitors of the ‘Super Mercedes’: ‘The rather unpleasant lateral swaying of the body would be dealt with by strengthening the slightly soft springs and by tightening the shock absorbers and would then probably cease; however the question remains whether the springing would be sufficient on poor rural roads – which predominate on long journeys – to retain the high average. As is the case with the new twelve-cylinder Maybach, it is very apparent here that future work must concentrate on improving the handling.’

The ‘Super Mercedes’ was the last very conservatively characterised new design from the still young Mercedes-Benz brand, which came about in 1926 as a result of the merger of the companies Benz & Cie. and DMG. The expectations that had manifested themselves in society with regard to an exclusive car from this brand turned out to be an advantage for it, its place in automotive society having been carved out by the predecessor models.

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Advanced engine with supercharging
The 7.7-litre eight-cylinder unit with its in-line design was a progressive, solid engine when compared with the eight-cylinder variant in the Nürburg model, but it could not be classed as sophisticated when compared with the engine in the forerunner of the Model 630. In comparison with the international competitors, one special feature did remain: the vehicle could be equipped – as an option at that time – with a supercharger which increased the output from 150 hp (110 kW) to 200 hp (147 kW). Another special feature of the W 07 model series was the fact that the car was available without a compressor with a deletion allowance of 3000 Reichsmarks. 13 customers availed themselves of this opportunity. The overhead valves were operated by a low-mounted camshaft via tappets and rocker arms. The cylinder head made of grey cast iron was sealed by an electron valve cover. The engine block of grey cast iron chromium-nickel alloy housed the crankshaft with nine bearings and was closed off at the bottom by an electron sump. The cylinder head contained eight spark plugs for the engine which worked with combined battery and magneto ignition.

For the naturally aspirated and belt-driven supercharger version the mixture was supplied via an updraught twin carburettor with an accelerator pump and choke. When the engine was cold the starting procedure was also made easier by preheating of the intake manifold.

The transmission represented a special feature, as an overdrive could also be selected in addition to the usual three forward gears, making a total of six forward gears available. The overdrive was preselected via a lever on the steering wheel, and activated by briefly decelerating without pressing the clutch. The same method was used for shifting down. Throughout the entire construction period the ‘Super Mercedes’ of model series W 07 had the two final-drive ratios i = 4.5 and i = 4.9 at its disposal.

In the case of the early vehicles, lubrication of the chassis was carried out automatically via a central lubrication process which involved the engine oil being pumped out of the sump at the appropriate points of lubrication. On the later models the usual central lubrication employed at Daimler-Benz then was used, whereby every 100 kilometres the tappet of a pump which had to be operated by foot supplied the lubrication points with oil.

The low-frame chassis offset at the front and rear with cross bracing in the centre consisted of closed U-section steel side members.

The front axle, a rigid axle made of chromium-nickel steel with an H-section and the rear rigid axle were connected with the frame by long semi-elliptic springs and were supported in their springing work by lever-type shock absorbers.

Where the early vehicles were concerned, changing the wheels was a tiresome business: the 2.7-tonne car had to be raised manually using a jack. Later cars offered a built-in hydraulic hoist which raised individual wheels. The wheels used were variously-sized wire spoke wheels or what were known as artillery wheels. The latter were wood spoke wheels which had originally been used for heavy artillery canons. 7.00 x 20 low-pressure tyres, 190 x 20 ‘giant pneumatic tyres’ and 8.25 x 17 low-pressure tyres were used.

What was striking during the production period of this ‘Super Mercedes’ was the change in body style that took place within this time, which spanned nearly eight years. To start with there were still very sharp-edged bodies with upright windscreens and tail ends without boots, but over the course of time more rounded shapes developed, as did windscreens which were positioned at more of an angle and what were at first boots merely added on, before they were finally integrated into the overall shape. The wheels were also quite isolated, particularly the front wheels, as they were only covered by a curved sheet metal panel serving as a wing. As time went by, the wings too, with their deep aprons and the wheels they housed, could be seen more as an integral part of the overall design and gave the side view of the body a more homogeneous appearance. It is also interesting to note that the top speed of the final models was raised from 150 km/h to 160 km/h – without increasing the engine output – a modest success achieved by rounder bodies. A special feature in the range of Mercedes-Benz passenger cars was the multifunction steering wheel with five additional functions: these included sounding the horn using the signal ring, turning up and dimming the lights via the button (adorned with the brand emblem featuring the star and laurel wreath) positioned in the centre of the steering wheel, and control of the fuel/air ratio, ignition and overdrive functions which were operated via three levers.

According to the 1931 brochure the range of bodies on offer comprised the Pullman saloon, Cabriolet D, Cabriolet F and open-top touring car.

The 1935 brochure depicted the following body versions: Pullman saloon with a rear-deck luggage rack, Cabriolet D with a boot, Cabriolet F with a rear-deck luggage rack and an open-top touring car with a rear-deck luggage rack.

In 1937 and 1938, the chassis of model series W 07 was then on sale for 24,000 Reichsmarks. By setting this more favourable price the company was reacting to the significant decrease in demand that there had been since 1936 in view of the advent of the new ‘Super Mercedes’ of model series W 150, with its considerably more up-to-date technology.

The prices are those given in the brochure and to a certain extent they should be regarded as orientation values, as hardly any vehicles produced were identical, and Cabriolet-F bodies with a boot and the Cabriolet C not listed in the brochure were also supplied.

The following are examples of body assemblers who delivered bodies for the ‘Super Mercedes’ (W 07):
Auer, Stuttgart-Bad Cannstatt
Erdmann & Rossi, Berlin-Halensee
Josef Neuss, Berlin-Halensee
Papler, Cologne
Reutter, Stuttgart
Voll & Ruhrbeck, Berlin-Charlottenburg

VIP customers included:
German Reich Chancellery, Berlin
Wilhelm II of Hohenzollern, former German Emperor, Apeldoorn/Netherlands
Emperor Hirohito, Japan
Archduke Josef, Budapest
Admiral Miklós Horthy, Budapest Germany Embassy, London
Otto Wolff, Cologne, industrialist and Member of the Supervisory Board of Daimler-Benz AG from 1926 to 1940
Lord Mayor Karl Fiehler, Munich
Federico J. Vollmer, wholesale merchant, Hamburg
Axel Tidstrand, Sågmyra/Sweden

In total, 119 vehicles of the ‘Super Mercedes’ (W 07) model were sold between 1930 and 1938; the number of units was spread as followed:

42 Pullman saloons
26 open-top touring cars 18 Cabriolet D
8 Cabriolet F 4 Cabriolet C
2 Cabriolet B 19 chassis, of which 4 were sold to Erdmann & Rossi
13 vehicles of these were supplied without a belt-driven supercharger

Another point to note is that there was never any such model as a 770 K, which has cropped up in the literature from time to time. The model designation is always: Mercedes-Benz Model 770 ‘Super Mercedes’. This also applies to its successor, the model series W 150 presented in 1938.

On the path towards the model series W 150 there were small quantities of an interim vehicle, the model series W 24, of which six cars were built for the Reich government. From the exterior it corresponded to a great extent to the early versions of the ‘Super Mercedes’ of model series W 150 and is often confused with it. From a technical point of view, however, they were worlds apart. As its source of power the model series W 24 had the 5.4-litre supercharged engine of the Model 540 K, which had an output of 115 hp (85 kW) without support from a belt-driven supercharger and 180 hp (132 kW) with supercharging. As far as the structure of the chassis was concerned, it was a hybrid design, which underlined this vehicle’s interim status: the frame was a box section frame, as was the case for all the large Mercedes-Benz models up until then. At the front the W 24 model series still had a rigid axle with semi-elliptic springs, but the rear axle was a modern DeDion axle with coil springs, which was used at the instigation of passenger car design engineer Hans Gustav Röhr, who had recently arrived on the scene. This design became the precursor of the DeDion rear axle which was later to be used in the W 150 model series and which was always referred to at Mercedes-Benz as the parallel wheel axle. The vehicles belonging to model series W 24 never went by one of the usual official model designations; internally they were occasionally referred to as ‘540 K (long wheelbase)’. Nothing is known of the whereabouts of the cars delivered to the Reich government.

Source: Daimler AG

He had already taken over from Daimler once before, at Austro Daimler’s forerunner, the company Austrian Daimler-Motoren-Gesellschaft mbH in the town of Wiener Neustadt. What was not known at the time was that Porsche’s main development focus was also more on large and expensive cars rather than small and lower-priced models. So in hindsight it is not surprising that the first project Porsche undertook was to design a representative twin model series of new luxury vehicles with displacements of 4 litres and 6.2 litres. The only differences between the two were to be found in the swept volume of the engines, in the wheelbase, the overall length and a few points of detail in the body. The length available for the body on the chassis and the technically sophisticated basis were identical. The larger engine required a wheelbase that was 120 millimetres longer and resulted in the chassis weighing 100 kilo­grams more.

Porsche followed his previous convictions at DMG, too, believing that a good and powerful engine also had to be aesthetically pleasing. For the new six-cylinder engines he adopted the basic concept that he had also used for his engine designed at Austro Daimler, from that company’s Model AD 617. The common features were the light silumin-cast crankcase with drawn-in dry cast cylinder liners, the crankshaft with only four bearings and the removable cylinder head with an overhead camshaft, which used rocker arms to operate the valves positioned in line via valve levers. The camshaft was driven by a vertical shaft driven from the clutch side. Together with the manual transmission the engine formed a cohesive component and thus at the same time a huge functional block. It comprised all the levers required to operate the car, including the steering gear and the steering column with the steering wheel. Fitted to the transmission were the starter, the air pump for inflating the tyres in case of damage to them, the hand levers for the gearshift and handbrake plus the pedals for the clutch and brake.

For his new designs at DMG, which arrived on the market in 1924, Porsche adopted the principle of supercharging which had been introduced by Paul Daimler. The positive-displacement belt-driven supercharger, with a high-ratio design of around 1 : 3, was located at the front end of the engine in a light-alloy housing fitted with cooling ribs. It was switched on by pressing down the accelerator, similarly to the kickdown position familiar from today’s automatic transmis­sions, via a multiple-disc clutch. When the accelerator was released it was slowed down by a multiple-disc brake located on the crankshaft. For the two large touring cars Porsche used the principle of the pressure carburettor engine – situated between the belt-driven supercharger and the combustion chamber – which had long been championed at Daimler-Benz.

An early form of the multifunction steering wheel
The characteristic features which stood out at that time compared with the passenger cars produced up until then were the removable cylinder head, the dry multiple-disc clutch in place of the double-cone clutch with a leather gaiter used thus far, the slightly pointed nickel-plated honeycomb radiator instead of the previous more deeply contoured and painted pointed radiator, the introduction of an actuating ring on the steering wheel for operating the horn by pressing the upper part of the ring and the dimming device by pressing the lower part of the ring, and the internal expanding brake for all four wheels.

In Porsche’s two-passenger car with a 4-litre and 6.2-litre engine, the Model 24/100/140 hp with the larger unit was the driving force – not in terms of the number of vehicles built – the smaller and less-expensive car retained the upper hand there. But when it came to the image factor – esteem, as people would say in those days – the car with the brawny engine was clearly the more representative vehicle.

Over the years changes were made to the model designation. To start with it was called the Mercedes 24/100/140 hp, and then after the merger in June 1926 Mercedes-Benz 24/100/140 hp. In 1928 it became the Model 630, as the previous rather cumbersome name was not much of a purchasing incentive, and also the aim was to introduce uniformity with the Stuttgart, Mannheim and Nürburg vehicle names, which were also given a model number which corresponded to the displacement.

The larger engine had a displacement of precisely 6240 cubic centi­metres, which, strictly speaking did not justify the figure ‘630’ in the model designation which was supposed to refer to the displace­ment. For nearly 100 years, history served up a parallel episode: the V8 engine installed by AMG today is also called a 6.3-litre engine, although it has a displacement of 6208 cubic centimetres.

In October 1928, the Model 630 was upgraded, whereby the more powerful engine with 160 hp (118 kW) from the K model was also supplied as an option for the normal touring car. In the plant’s docu­mentation this variant was described as the ‘Model 630 with a K engine’ or ‘6-litre car with a K engine’. This combination assumed the flagship position in Daimler-Benz AG’s passenger car range up until the ‘Super Mercedes’ appeared on the scene in October 1930. It developed into the somewhat more durable variant, and – eventu­ally – also the more sought-after one. Production of the chassis and car with the 140 hp (103 kW) engine ceased in 1929, that with the 160 hp (118 kW) K engine a year later. Naturally this did not exclude so-called stock vehicles from only being sold and registered much later.

As the years went by some changes were made so as to keep the vehicles up to date. These included those carried out in 1926 to replace the rear cantilever springs by semi-elliptic springs, which were fitted beneath the rear axle from the outset. From autumn 1927 the three metal tubes were added as trim for the exhaust pipes which ran on the outside of the bonnet at that time, and from October 1928 customers could choose to have the aforementioned engine from the Model K installed – just in the open touring car at first but then later in all the other body variants too. This was followed in 1928/29 by the inclusion of a Bosch-Dewandre brake booster.

As development continued there were only minimal changes to the range of bodies on offer. Particularly impressive features by current standards include the two open-top touring cars with five or seven seats, which were also available with an attachable saloon body in the style of a present-day hardtop. Between 1926 and 1928 the spectrum of bodies available and the pricing was as follows:

From 1929 onwards, the range of bodies was reduced, but the more powerful K engine could be ordered for an additional charge of 2,000 Reichsmarks (RM).

The bodies were manufactured either at the Sindelfingen plant or, as was the norm back then, especially where premium-segment cars were concerned, purchased from internationally renowned body assemblers in accordance with customer requirements. In this case special requests were then met, such as the extra-high Pullman saloon for Reich President Paul von Hindenburg, so that on official occasions he was able to wear his spiked helmet and in civilian dress his top hat inside the vehicle. Hindenburg also had a Pullman cabriolet at his disposal. Both cars were specially designed at the Josef Neuss car factory in Berlin.

The following are examples of well-known and renowned companieswhich supplied bodies for the Mercedes-Benz 24/100/140 hp Model 630:

Balzer, Ludwigsburg
Castagna, Milan D’Ieteren Frères, Brussels
Erdmann & Rossi, Berlin Farina, Milan
Geissberger, Zurich Hibbard & Darrin, Paris
Million Guiet, Paris Josef Neuss, Berlin-Halensee
Papler & Sohn GmbH, later, Papler GmbH, Cologne Van den Plas, Brussels
Saoutchik, Paris Voll & Ruhrbeck, Berlin-Charlottenburg
Zschau, Leipzig

VIP customers included:
Reich President Paul von Hindenburg
King Gustav of Sweden
King Alfonso of Spain
Emil Jannings, actor
Richard Strauss, composer
Richard Tauber, singer
Jan Kiepura, singer
Oscar R. Henschel, industrialist

In total, 1080 vehicles of the Mercedes-Benz 24/100/140 hp Model 630 were constructed between 1924 and 1930. In addition to this, there were also 117 vehicles with the powerful K engine.

Source: Daimler AG

Over the years, as well as various Mercedes-Simplex, the German Emperor’s fleet came to include three Mercedes-Knight, a Mercedes 28/95 hp, a Mercedes 15/70/100 hp and a Mercedes-Benz 770 ‘Super Mercedes’ Cabriolet F from 1932. Today the latter is on display in the Mercedes-Benz Museum, along with the 1935 armoured Pullman saloon of the same model, owned by the Japanese Emperor Hirohito.

By 1912 Benz & Cie. numbered the German Emperor, the Russian Tsars and the Swedish Royal Family amongst its most famous customers.

The sports-enthusiast brother of the German Emperor, Prince Henry of Prussia, was not only the founder and patron of the Prince Henry Tours named after him, as well as being the inventor of the wind­screen wiper; he himself often took part in events in his open-top 70 hp Triple Phaeton. A particularly impressive car was the Model 39/100 hp, built by Benz in the years 1912 to 1915. Because of its dimensions and clear lines it signalled a sense of noble distance. However the shock caused by the global economic crisis of 1907 led to Benz becoming established as a high-profile provider of vehicles to the lower middle class, but without losing sight of the spectrum of representative cars. It was with this concept that Benz succeeded in positioning itself clearly ahead of DMG in the period before the First World War in terms of the number of vehicles produced.

At DMG the dominant top-range car from 1910 to 1914 was the Model 37/95 hp. With its prestigious presence, its owners – who were often members of the aristocracy – were able to cut a grand figure. In 1913 the chassis came with a price tag of 23,000 Marks – the usual base price of the time. Then either the plant would fit an individual body to this or a body assembler would carry out the work. This was where the car manufacturers were in competition with the finest body assemblers of the day. With its large-piston four-cylinder engine with 9.5 litres of displacement and a chain drive system, however, it represented a dying form of automotive technology. For a period of many years, particularly in the case of vehicles with powerful engines, the cardan drive system was favoured over chain drive due to the gentler power transmission.

In 1914 it was replaced by the Mercedes 28/95 hp. As a premium-segment vehicle it took its leave of the four-cylinder engine and the chain drive system, like the Benz 39/100 hp. The six-cylinder engine, created by Paul Daimler, was built with a design largely based on that of the 1912 DF 80 aircraft engine, which was awarded the ‘Emperor’s Prize’. The engine had V-shaped overhead valves, which were operated via an overhead camshaft and rocker arms. The camshaft was driven from the front end of the crankshaft by a vertical shaft.

Due to the war only 25 units of Model 28/95 hp were manufactured during the years 1914 and 1915. Production started up again after the end of the war, when Paul Daimler took the opportunity to have the engine revised. The individual steel cylinders were replaced by cylinder blocks cast in pairs, but the coolant jackets welded in pairs remained. The valves which been open up until then were now sealed with oil-tight light-alloy valve covers for each cylinder pair. The mixture was supplied via two Pallas updraught carburet­tors, which each fed three cylinders. The two intake manifolds, again Y-shaped, were connected with each other via a balance pipe to ensure even mixture supply.

Following the First World War, the target groups of potential customers changed – the aristocracy diminished in importance in this respect, with personalities from the fields of economics, film, theatre, politics and industry taking its place. The Mercedes 28/95 hp remained in existence until 1924; there were 590 vehicles in all. Whilst the term ‘Super Mercedes’ was not coined until after its time, it was certainly deemed to be worthy of this description. The number of units built was substantial, especially bearing in mind the prevailing circumstances and compared with vehicles of a similar profile which would follow in its footsteps. But this imposing vehicle also served to cover a wide customer spectrum due to the fact that there were three different wheelbase versions, which meant that it was not restricted to just large saloons or open-top touring cars.

Source: Daimler AG

Through its very presence it has the effect of reinforcing impressive appearances – whilst it is true to say that appraisals will inevitably vary, depending on the particular epoch in question and the cars used in each case. They are always also a reflection of their time, and a representative car does not just impress with its stature and style; it often documents technical progress, too, and is admired for its outstanding comfort.

The tradition of representative vehicles from the Mercedes-Benz brand and the predecessor companies Benz & Cie. and Daimler-Motoren-Gesellschaft (DMG) is a story characterised by various interruptions. Having said that, up until 1981, the year in which production of the Mercedes-Benz 600 finished, it was absolutely indisputable that the brand had to be present in the exclusive vehicle category. Around another two decades would pass before the then DaimlerChrysler AG once again established itself in the high-end segment: with the Maybach brand in 2002.

The era of representative vehicles began at the beginning of the 20th century, some twenty years after the invention of the auto­mobile. It was initiated by the same circle from the wealthy bourgeoisie that made a name for itself as sponsors of motor racing. The businessman Emil Jellinek, for instance, was one of the friends and promoters of the car who repeatedly made significant contribu­tions to the vehicles’ advancement by providing some valuable food for thought in the early days. One of the results of this work was Jellinek’s 1907 touring car, which can now be admired in the Mercedes-Benz Museum, and which already embodied some of the fundamental characteristics of a representative vehicle. When he had a touring car built, Jellinek, who was always wont to think a little further ahead than many of his contemporaries, did not opt for one of the widespread tourer or phaeton carriages. Instead he chose a comfortable, imposing saloon, which – with an engine output of 60 hp (44 kW) – was in the upper echelons of the model hierarchy of the day. In contrast to many of his peers, Jellinek even thought of the driver, who was also protected from the elements by a fixed roof, doors and windows.

It should be pointed out here that back in those days the open carriage was the usual body form and the closed vehicle the special, exclusive variant, and in many cases this applied up until the end of the 1930s – for representative cars, too.

The nobility, predominantly lovers of horses and coaches, only discovered the car for representative purposes after the moneyed bourgeoisie. Tsar Nicholas, for example, is reported to have been a riding enthusiast who valued old customs – but not the car, at least not to start with. The German Emperor Wilhelm II is said to have had a similar attitude. Nevertheless the automobile gradually found its way into the aristocracy’s stables and slowly but surely turned them into car parks.

Source: Daimler AG

Commenting in October 1977, when the basic decision for a third model series was made, the chairman of the supervisory board at the time, Wilfried Guth, said: ‘The birth of the idea that smaller cars can also be built, and that Daimler can enter another market segment with them, was a very, very laborious and very slow process.’

The technicians and designers had already provided the hard facts a long time ago. But without impetus from the USA, presumably these activities would not have been carried out either. That was where the requests for a Mercedes-Benz as a second car were coming from. In addition, the environmental legislation of the Clean Air Act laid down clear specifications for fleet consumption (Corporate Average Fuel Economy, CAFE) and also for the fuel economy of the model ranges sold in the USA. So in 1985, for example, an average consumption of 27.5 miles per gallon (equivalent to 8.6 litres per 100 kilometres) was stipulated. It was not possible to comply with this figure with the model range available at that time.

The specifications for the W 201 model series presented in February 1974, under the direction of Hans Scherenberg, already clearly laid out the key elements and dimensions of the future smaller Mercedes-Benz. The dimensions were so clearly defined that the series production vehicle that was launched on the market almost nine years later hardly deviated from the specifications. And the speci­fications also laid down one other thing at that time: ‘Due to the characteristics expected of the brand symbol by customers in terms of quality, safety and refinement, the 201 should consciously differentiate itself from the other vehicles of the mid-range series.’

Werner Breitschwerdt, still head of bodywork in Sindelfingen at the time, under Scherenberg, did not waste much time and in 1974 had a vehicle from the W 115 model series cut up lengthwise and breadthwise and pieced back together based on the reduced dimen­sions of the planned W 201 series. In this way he was immediately able to gain an initial impression of the space.

The W 201 model series represented the clear signal for the start of a new age: the brand was becoming younger. The new smaller Mercedes-Benz proved this by not only setting an example in terms of technology, comfort and safety, but by also heralding the start of a new era in terms of its design. Werner Breitschwerdt and Bruno Sacco came from a new generation of management who turned their understanding of a new modern Mercedes-Benz into reality with the W 201 model series. As such, they can be justifiably described as the fathers of the third model series.

The first designs from 1974 still looked somewhat like small S-Classes from the W 116 model series. These so-called ‘Mercedesle’, as they were once appropriately described by designer Andreas Langenbeck, did not correspond to Sacco’s concept because they did not convey any formal individuality. He brought a halt to proceedings and prescribed some time-out from the project for his staff in order to gain a fresh, clear view of things. Claus Hieke, who subsequently became responsible for AMG design, still believes that Sacco’s biggest contribution was recognising that simply scaling down the dimensions of cars does not really achieve the desired aim.

In order to distance themselves from the project in creative terms, Breitschwerdt and Sacco let staff handle other projects, so as to be able to make a fresh attempt after a certain period of time had elapsed. The race was won in 1978 by a design from Peter Pfeiffer, which although still implemented as a coupé at the time, also comprised all of the essential elements of the subsequent W 201 bodywork, such as the inconspicuous kink running from the roof through the rear window and into the edge of the boot lid. But this design was also characterised by details which were only incorporated much later, such as the door handles, which went into series produc­tion in the C 126 model series SEC Coupé in 1981; the contrasting colour plastic side parts, incorporated into the range with the facelift in 1988; or the integrated grille, implemented in the W 140 model series S-Class in 1991. At the board meeting in Sindelfingen on 6 March 1979, the executive board gave the final approval for the design. The bodywork was impressive, with its formal coherence, and became the trademark of a new design era at Mercedes-Benz. The new smaller Mercedes-Benz, affectionately named the ‘Baby Benz’ in the USA, still impresses with its fresh appearance many years on.

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As trend-setting as the design of the W 201 model series proved to be for Mercedes-Benz at the time, equally impressive were its handling, ride comfort and of course its passive safety too, all of which were just as good as the larger models. Making its debut was the introduction of independent multilink rear suspension, which helped to provide a high degree of driving safety with a level of ride comfort previously unknown and which is still basically produced today, albeit in an adapted form on the later models. The combination of agile handling, previously unheard of in Mercedes-Benz passenger cars, and ride comfort was unique in such a compact vehicle and acknowledged worldwide.

The W 201 model series was produced up until 1993. It evolved into the C-Class, with the development of the 202 model series, which in the meantime has become available in a wide variety of body and engine variants.

NAFA – the ‘local transport vehicle’
Congested roads, the need for parking spaces and long traffic jams raised new questions in terms of vehicle research. Mercedes-Benz responded to these issues in 1981 with the ‘local transport vehicle’ concept study, or NAFA for short (after the German ‘Nahverkehrs-fahrzeug’). Measuring 2.50 metres in length and 1.50 metres in both width and height, the innovative two-seater contradicted everything that the company had previously been known for.

Thanks to four-wheel steering, the car could also be driven forward into narrow parking spaces, and its turning circle was no more than 5.7 metres. Even when clearance at the sides was restricted, two sliding doors helped make getting into and out of the vehicle convenient: they opened forwards and the exterior mirrors folded in automatically. The car featured front-wheel drive and an automatic transmission. Air conditioning, power steering and seat belt tensioners were also included. The comparatively high seating position, low beltline and large window areas also ensured it enjoyed optimum all-round visibility.

The NAFA study was not developed further into a series production vehicle. But it did not simply vanish into obscurity: the knowledge gained from it went into the design of the A-Class, the prototype of which made its debut in 1996. And the concept of a compact city car celebrated reaching the production stage in the form of the smart City Coupé, introduced in 1997 and known today as the smart fortwo, which has since gone on to be mass produced in large quantities.

Mercedes-Benz A-Class (W 168, 1997 to 2004)
The desire for a car with very small external dimensions, and at the same time all of the values of the Mercedes-Benz brand, started to take shape at the start of the 1990s. Mercedes-Benz introduced the sandwich principle, in which the body is divided into two horizontal planes: the drive unit is located in front of and under the floor pan, so that in the event of a crash it is pushed down and out of the way and does not penetrate into the interior.

In September 1993, Mercedes-Benz gave the public a foretaste of theA-Class at the International Motor Show (IAA) in Frankfurt/Main. Here the brand presented its Vision A 93, a front-wheel drive car featuring an innovative body design in which the engine, transmis­sion, tank and axles were located below the passenger compartment: the sandwich principle had become a reality, and the combination of small external dimensions (length of 3350 millimetres) with a large, variable interior, and a Mercedes-Benz standard level of safety, proved impressive. The Vision A 93 incorporated elements of the F 100 research vehicle, for example. The body of the one-off vehicle was made completely of aluminium. The concept of intelligent light­weight construction was later developed for the A-Class. It combined different materials such as steel, plastic, aluminium and magnesium. As such, the vehicle design was optimised just as much in terms of weight and environmental compatibility as it was in terms of costs.

The Vision A 93 demonstrated the versatility of vehicle design with three different engine variants. In addition to an economical petrol engine producing 55 kW and a direct-injection diesel engine producing 44 kW, there was also a version featuring a 44 kW electric drive. The one-off vehicle also boasted variability in the interior: the car could be modified depending on the situation – from a comfortable four-seater through to a cargo maestro with a stowage compartment volume of 1000 litres. This revolutionary space concept was once again based on the innovative, high horizontal frame floor assembly, which helped to ensure a level of crash safety previously unavailable in this vehicle category.

In 1994, Mercedes-Benz displayed a version of the concept vehicle named ‘Studie A’, modified in a number of details, at the Geneva Motor Show. The American magazine ‘Motor Week’ awarded it the title of ‘Best Concept Car 1994’.

The positive response from the press and public lead to a quick decision being made by the Mercedes-Benz executive board. It was only in December 1993 that it had decided on series production of the A-Class. The project was assigned the model series number W 168, and the vehicle was to be produced at the Rastatt plant. At the International Motor Show in Frankfurt in September 1995, two years after the world premiere of the Vision A 93, the interior design of the A-Class was presented. Compared with the one-off vehicle, the overall length of the vehicle had in the meantime grown by 225 millimetres – and this was even before respectable space requirements increased further, particularly in terms of the luggage compartment.
The sandwich concept proved successful in 1996 in various crash tests at the development centre in Sindelfingen. The tests proved that even a vehicle with small crumple zones can still achieve the high safety standards of Mercedes-Benz. Furthermore, the A-Class not only fulfilled future EU guidelines for frontal impacts, but also complied with the strict safety specifications of the USA and the European Union for side collisions.

The A-Class finally made its official premiere in March 1997. Mercedes-Benz presented the five-door version at the Geneva Motor Show. The commercial release followed eight weeks later in May 1997, and the car was then available in dealerships by October. Despite the ‘elk tests’, the A-Class was extremely successful and was initially offered with three engines and four power output levels. These included the 1.4-litre petrol engine producing 60 kW (82 hp) in the A 140, the 1.6-litre petrol engine producing 75 kW (102 hp) in the A 160, and the 1.7-litre turbodiesel engine available in two power outputs of 44 kW (60 hp) in the A 160 turbodiesel, and 66 kW (90 hp) in the A 170 turbodiesel. As part of a facelift in 2001, a version with a longer wheelbase was also introduced.

Mercedes-Benz A-Class (W 169, as from 2004)
The second generation of the A-Class followed in 2004 in the guise of 169 model series. This was available as before in a five-door version (W 169), but also as a three-door variant (C 169). Production of the three-door variant came to an end in July 2010.

In terms of engines, as part of the further enhancement of the model a comprehensive offering designed to meet a variety of performance requirements evolved. In the diesel segment, three power outputs of the compression-ignition engine, featuring a displacement extended to 2.0 litres, became available: 60 kW (82 hp) in the A 160 CDI, 80 kW (109 hp) in the A 180 CDI and 103 kW (140 hp) in the A 200 CDI. In the case of the petrol engines, three displacement classes were covered with 1.4, 1.7 and 2.0-litre engines. These resulted in four power outputs of 70 kW (95 hp) in the A 150, 85 kW (116 hp) in the A 170, 100 kW (136 hp) in the A 200 and 142 kW (193 hp) in the A 200 Turbo. The A-Class also formed the basis for the Compact Sports Tourer from Mercedes-Benz which was launched onto the market in 2005, designated as the
B-Class, which also went on to become a very successful model.

Mercedes-Benz B-Class (T 245, 2005 to 2011)
The B-Class made its debut at the Geneva Motor Show in 2005, and went on to celebrate its market launch in July 2005. With this compact sports tourer, Mercedes-Benz combined the highlights of existing designs: the variability of the minivan, the space of an estate, the dimensions of a compact car, and the sporty, emotionally-appealing design of a sports car.

The wheelbase of the floor assembly was increased to 2778 milli­metres. This resulted in high levels of spaciousness and comfort thanks to generous interior dimensions – increased even further compared with the A-Class – and also a load capacity of up to 2245 litres. The high-class appeal of the high-quality materials highlighted the special position enjoyed by the B-Class.

In the event of a crash, the dynamic two-box design of the body featured maximum absorption of kinetic energy, with minimum occupant loads and intrusion into the passenger compartment, and once again demonstrated that Mercedes-Benz places passive safety at the very highest level in the field of compact cars too.

The range of engines, taken from the closely-related – in design terms – A-Class, comprised in the diesel segment two power output variants of the 2.0-litre diesel engine, producing 80 kW (109 hp) in the B 180 CDI and 103 kW (140 hp) in the B 200 CDI. The petrol engines meanwhile, also similar to the A-Class, included three displacement classes of 1.4, 1.7 and 2.0 litres. These were available in four power output levels of 70 kW (95 hp) in the B 150, 85 kW (116 hp) in the B 170, 100 kW (136 hp) in the B 200 and 142 kW (193 hp) in the B 200 Turbo.

The B 150 to B 200 models came with a manual five-speed transmis­sion as standard, while the B 180 CDI, B 200 CDI and B 200 Turbo had a manual six-speed transmission. The AUTOTRONIC stepless automatic transmission was also offered as an optional extra.

In March 2008, the B-Class underwent a facelift, celebrating its market launch at the end of June 2008. Significant new features included an ECO start/stop function for the B 150 and B 170 models, and the introduction of a bi-fuel variant in the form of the B 170 NGT, which can be driven with both natural gas and premium grade fuel. Other changes occurred in terms of the appointments, where highlights included the optional Parking Assist and the standard Hill-Start Assist.

The B-Class has become a success. With this model, Mercedes-Benz has fulfilled the requirements of a large customer base for a high-quality, compact, spacious and flexible vehicle suitable for everyday use, offering a high seating position and convenient entry options. The next generation, the W 246 model series, is now ready to enter the same market segment. Making its debut at the 2011 International Motor Show in Frankfurt/Main, it is once again placed to set new standards.

Source: Daimler AG

It was a compact car with an overall length of 3.70 metres. It had two doors, a bench seat in the front for up to three people and another small bench seat in the rear for younger passengers. This two-door vehicle was driven by a four-cylinder engine with overhead camshaft and a displacement of 1.2 litres, derived from the 1.8-litre six-cylinder engine which was also in the project stage. Commenting on it in March 1949, chief engineer Fritz Nallinger said: ‘The design of a light, 2- to 2½-seater car (560 kg) decided on at that time has seen a great deal of progress in the meantime and is showing some promising results.’ Nevertheless, the vehicle, along with the two engines, remained stuck at the project stage. The 1.8-litre unit was subsequently developed into the M 180 model series 2.2-litre engine for the Mercedes-Benz 220.

Mercedes-Benz W 122 model series
A good three years later – while the passenger car model portfolio had in the meantime once again come to comprise the full established range, from the 170 V model through to the luxury car – the Daimler-Benz board took the decision at its meeting of 2 February 1953 to design a car based on material and labour costs that were 15 to 20 lower than those of the 170 V model. It was to be the successor to the 170 V and 170 D models (W 136 I model series), after replacing the 170 S with the 180 model (W 120) in the autumn of 1953. Nallinger described the new vehicle thus: ‘It is clear that the body must be new, with a smaller interior and smaller window areas compared with the W 120. Width and length will be like the 170 S, two-door body, bulkhead, dashboard, luggage compartment like the W 120, front seats like the 170 V.’

By 1956, the vehicle then referred to internally as the W 122 had reached a considerable degree of maturity. Based on all of the ingre­dients, it had the makings of a very successful future. Nevertheless, it did not make it into series production for two reasons: firstly, in 1958 Daimler-Benz took over Auto Union and as a result there was a certain conflict of interests between a large DKW and a small Mercedes-Benz. Secondly, shortly before their market launch the existing models of the W 111 model series, as planned in their last version with their new safety concept of a W 122 model series on the conventional platform of the W 120 model series, were left appearing somewhat obsolete.

By today’s standards, the appearance of the W 122 model series is extremely interesting: experiments were already underway with the design of an SL-look saloon as early as the mid-1950s. At the time, it was intended to replace the traditional Mercedes-Benz ‘face’. Many years later it was offered as an alternative in the C-Class (204 model series), as part of the Avantgarde equipment line.

Mercedes-Benz W 118/W 119 (1960s)
Nallinger did not give up on his idea of an entry-level model, or lower end model, as he defined this vehicle group. With the purchase of Auto Union in particular there was a need for development in the medium term, since it was conceivable that the two-stroke vehicles under the Auto Union brand of DKW would not have a future, and there was still a need for a Mercedes-Benz product below the current model classes in order to achieve a coherent overall portfolio.

As a result, around that time the advance development department in Untertürkheim – headed up by Ludwig Kraus – designed a vehicle which was assigned the project designation W 118. For this the engineers planned to use a valve-controlled, horizontally opposed engine with a displacement of 1.5 litres and front-wheel drive. At the same time, a new highly-compressed four-cylinder inline engine (M 118), with a displacement of 1.7 litres, was also tested. The W 118 was developed further into the W 119. This had a new highly-compressed engine, called the ‘H-engine’ by Daimler-Benz, which boasted a high compression ratio of 1 : 11.2 and was also very economical. With their SL face, low beltline, roof attachment clearance and rear design, the test vehicles produced were close to the Mercedes-Benz 230 SL (W 113) in terms of style. Even when considered by today’s standards, the appearance of the model series is still considered to be very respectable.

In 1962/63, when problems arose with the two-stroke engines of the DKW F 102 at Auto Union, the Daimler-Benz subsidiary at the time, Nallinger dispatched Kraus to the town to help with damage limitation. In his luggage he had the plans for the W 119 model series and the H-engine. This came to be used from the mid-1960s at Auto Union, where it was designated the ‘intermediate pressure engine’. As a result, Daimler-Benz provided the subsidiary with a solution to the two-stroke engines, which were no longer considered contemporary, in the form of more modern four-stroke engines. Auto Union was sold to Volkswagen in 1964/65.

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Shortly before his retirement in December 1965, Nallinger said: ‘For his part he assumed that this model – which, as indicated, we were already testing – would possibly be produced at BMW or Auto Union.’ And then continued to comment on the programme: ‘I believe that such a second car model, which can also be viewed as a collective model, must now [,many years later therefore,] be redesigned as quickly as possible and the issue of its testing tackled [...].’

We should perhaps give a brief explanation of the reference to BMW here: at the end of the 1950s, the company was experiencing financial difficulties which were to be addressed with the help of the Deutsche Bank and the involvement of Daimler-Benz.

Source: Daimler AG

With the ‘Velociped’ engine, called ‘Velo’ for short, Benz’ aim was to build a lightweight yet resilient vehicle which at the same time was also reasonably priced, and which also stood out from the heavy motorised carriages of that time. That is why Benz, himself a keen cyclist, also called it the ‘Velo’, thus creating a link with the bicycle. Fitted with spoked wheels, the vehicle also gave the impression of being appropriately sized, measuring no more than 2.25 metres long and weighing 280 kilogrammes at the time of its launch. Over the course of the model’s history, due to various modifications, admittedly it gained some weight: the Comfortable model dating from 1902, towards the end of the model’s long career, weighed 425 kilogrammes. The power of the engine also increased as a result of customer requirements. The 1.1 kW of the original model became 3.3 kW over the years, while the displacement remained the same.

Optional extras were also even available at the time, at an additional cost: with the basic 1.1 kW engine, the Velo cost 2000 Marks. The 2 kW engine pushed the price up by 10 per cent to 2200 Marks. The ‘Velo Comfortable’ also offered this level of performance and cost 500 Marks more than the basic model. From 1896, the Velo could also be ordered with a three-speed transmission, at an additional cost of 200 Marks. Useful accessories offered by Benz included pneumatic tyres (350 Marks), a half roof in spray leather (200 Marks) or a parasol (100 Marks) to protect against the sun.

The basic version of the Velo was built until 1900, and the Comfortable variant until 1901. It was one of the most important mainstays of the Benz & Cie. vehicle range in its day – and made a significant contribution to establishing Benz as the world’s largest automotive manufacturer at the turn of the century. This fact is also reflected in the company’s production figures compared with those of DMG: in the years from 1894 to 1900, Benz built 2248 vehicles, as opposed to DMG’s 302 vehicles.

Benz 8/18 hp (1911)
The Benz 8/18 hp, another smaller vehicle, was introduced in 1911. The saloon version of the 8/18 hp was available at a price of 8500 Marks and thus more reasonably priced than its predecessor, the 10/18 hp Saloon, which carried a price tag of 11,000 Marks. The 8/18 hp model enjoyed widespread sales success. At the same time it was an early example of ‘downsizing’. Compared for example with the Benz 18 hp of 1905, the four-cylinder model delivered the same output but with a displacement which was almost 40 per cent less. The 8/18 hp was therefore more efficient and also helped to save on tax – the luxury car tax introduced in 1906 was based on engine displacement.

The 8/18 hp model was the result of an internal company competition to build a smaller car which was less expensive, more robust and cheaper to run than all of its predecessors in this class. These requirements were most closely met with the design submitted by Benz designer Karl Ketterer. He adopted an approach based on the division of labour: production and material costs were calculated by a colleague from purchasing who would later play a special role in the history of Daimler-Benz AG – Wilhelm Kissel. Ketterer won the competition and between 1911 and 1921 the 8/18 hp model became a mainstay of the passenger car range of Benz & Cie. In 1912, it received a facelift and at the same time took on the designation 8/20 hp.

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With a displacement of two litres, the engine produced an output of 13 kW at 1800/rpm which was delivered to the rear wheels via a four-speed transmission. The maximum speed was quoted as 62 km/h. Benz offered an unusually extensive body range for the 8/18 hp model. Customers could chose from versions including a runabout available in two equipment variants, a two-seater sports car, a saloon and a landaulet. The advertising statements of the time captured it in a nutshell, using the characteristic style of language of that era: ‘As the best of the good, we have quietly, stayed true to the principle we represent with our car: the 8/18 hp.’ The vehicle enjoyed widespread appeal among many of existing customers, and also enabled the company to win quite a few new ones and as a result Benz significantly increased its lead over DMG in terms of production figures. Between 1911 and 1914, Benz produced 9980 passenger cars, compared with DMG’s 6327 units.

Mercedes 8/18 hp (1911)
In August 1911, the Daimler-Motoren-Gesellschaft reacted exactly like its competitor, Benz & Cie., to the increased demand for more reasonably priced, quality vehicles with a new model. Admittedly, the Mercedes 8/18 hp did not quite enjoy the same response as the model from Benz, however it did become a success for DMG, despite the chassis of the vehicle from Swabia being 11 per cent more expensive – with a price tag of 7000 Marks – than that of the Benz 8/18 hp. The board member responsible for production, Adolf Daimler, told his colleagues that of the 1305 chassis built by DMG in 1911, only 300 ‘had to be assigned to the 8/18 hp “cardan” (propeller shaft drive) car’. Available bodies included a two-seater sports car, phaeton and landaulet.

Like its competitors in Mannheim, in 1912 DMG in Untertürkheim increased the power output, and the 8/18/hp became the 8/20 hp. A year later, the displacement was increased to 2064 cubic centi­metres, a move which was accompanied by a lengthening of the wheelbase from 2760 to 2890 millimetres. Now called the 8/22 hp, the model remained unchanged and continued to be built until 1922. The top speed was stated as 60 km/h.
Both cars featured similar vehicle and engine designs. Both shared a side-valve four-cylinder engine, four-speed transmission and propeller shaft drive, which was not yet commonplace at the time. Unlike the Benz engine, with its cylinders comprised in a cylinder block as well as inlet and outlet ducts, the Daimler engine had two cylinder blocks which sat on a joint crankcase and featured external inlet and outlet ducts.

Detailed production figures for both models are no longer available. At the time, however, they were the cars produced in greatest numbers by both manufacturers: Benz & Cie. and Daimler-Motoren-Gesellschaft both recognised the trend towards small, quality products in good time, and reacted accordingly in line with market demand.

Mercedes 6/25 hp and projects in the 1920s and 1930s
At the end of 1921, DMG surprised everyone in Berlin at the first automobile exhibition in Germany after the First World War with the small supercharged 6/20 hp model. The new entry-level Mercedes model, designated the 6/25 hp, was the first series pro­duced passenger car featuring a supercharged engine – together with its sister model, the 10/40 hp. The innovative engine technology stood for efficiency, but was also sophisticated and expensive. This proved an obstacle to achieving high sales, particularly in the case of the entry-level 6/25 hp which saw only 350 units being built between the end of 1922 and 1924. Nevertheless, the 6/25 hp model managed to secure its place in automotive history by forming the basis for the unique success of the Mercedes-Benz supercharged cars of the 1920s and 1930s.

A new attempt at producing a smaller vehicle followed immediately after the merger of Benz & Cie. and DMG into Daimler-Benz AG. Below the equally newly-developed six-cylinder Mercedes-Benz 8/38 hp (W 02, 1926 to 1928) with a displacement of 2 litres, a vehicle with a displacement of 1.4 litres was also planned – this too was to be a six-cylinder car, designated internally as the W 01. Eight prototypes were made of this car, however it did not reach the series production stage.

It was a similar story with the second attempt at producing a smaller Mercedes-Benz. A total of 28 prototypes were produced of the four-cylinder 5/25 hp model, which reached the planning stage in 1928. However, the vehicle fell victim to a lack of financial resources, which were needed to extend the production facilities. Despite being quite contemporary, this small Mercedes was somewhat conservative in terms of its technical design, particularly with regard to the suspension which had rigid front and rear axles, as well as its box section frame.

Basically, for Mercedes-Benz these small vehicles were closely related in design terms to the existing six-cylinder models with displacements of 2 and 2.6 litres (called the Stuttgart model from the end of 1928) as well as those with a displacement of 3.1 and 3.5 litres (called the Mannheim model from the end of 1929).
In the beginning of 1929 Hans Nibel, who came from Benz in 1926, became the sole chief engineer. He was also joined by the head of design Max Wagner, and the head of testing Fritz Nallinger, from Mannheim. Nibel and Wagner had already familiarised themselves with advanced vehicle designs at a very early stage. One such example which springs to mind is the Benz mid-engined racing car of 1923, which was way ahead of its time. Now the two men put their ideas and experience into practice.

The first project was the W 17 model series. Twelve prototypes of this test model were produced in 1931. It had a rear-mounted air-cooled four-cylinder horizontally opposed engine in the rear with a displacement of 1.2 litres and an output of 18 kW, key specifications which were already similar to the subsequent VW Beetle. However the operating noise of the engine was too loud, and so this concept was not pursued any further. Other interesting projects to emerge from this time were a very early prototype using experimental bodywork, which would have done credit to an oversized coal box on wheels, and also a near production standard and rather appealing test car with various formal similarities to a vehicle which appeared quite a number of years later – the VW Beetle.

Mercedes-Benz 170 (W 15, 1931 to 1936)
Success was achieved with the 170 model (W 15), on the other hand. The inexpensive and technically innovative entry-level model celebrated its premiere at the Paris Motor Show in October 1931 – and was a tremendous success in terms of sales. By 1932 no fewer than 4438 units were produced, more than the previous year’s entire production figures for all Mercedes-Benz passenger car models. As such the W 15 played a large part in ensuring Daimler-Benz successfully overcame the difficult economic times of the early 1930s.

The latest technical achievement entailed equipping the car with front and rear swing axles, namely independent wheel suspension. The modern technology and appealing shape of the car proved just as popular as the low price, despite its six-cylinder engine. The four-door Saloon variant of the vehicle cost 4400 RM (Reichsmark), almost 1600 RM less than the most reasonably-priced version of the Stuttgart model. As such, as the vehicle featuring the smallest displacement and the most reasonable price, it successfully occupied the low-end position in the Mercedes-Benz passenger car range.

In its first year of production, the 170 model was only offered as a four-door Saloon and a four-seater Cabriolet C. Striking features included that the small but standard external luggage case, initially available in a free-standing design and subsequently incorporated directly into the bodywork from 1934. From April 1932 the chassis was also made available for fitting third-party bodies. In September 1932 a two-seater ‘special-edition Roadster’ was added to the range, followed a year later by the ‘Special Cabriolet A’, which became the most expensive variant of the 170 model with a price tag of 7000 RM. In February 1934, another two-door touring car with four seats was introduced, which was optionally available with either a body fitted in Sindelfingen or third-party body. During the same period, the four-door Saloon also came with an optional roll-back roof fitted at the Sindelfingen production works.

In February 1935, a two-door saloon also made its debut which already hinted at the body design of the successor model, the Mercedes-Benz 170 V; at the same time, the existing flat radiator was replaced on all body variants by a radiator featuring a flat wedge shape.

In addition to the body variants mentioned, between 1932 and 1935 the 170 model was also offered as a box van with a payload of 300 kg. The model designation, L 300, followed the naming conven­tion used for Mercedes-Benz truck models.

The 170 model was replaced in the spring of 1936 by the 170 V (W 136 – until 1942), which had nothing in common with its prede­cessor apart from the displacement class. Completely redesigned in technical terms, the 170 V model was fitted with a four-cylinder engine.

A total of 13,775 units of the Mercedes-Benz 170 were produced. On top of this some 126 examples of the L 300 van variant were also produced.

Source: Daimler AG

Board member Wilhelm Kissel, from 1937 to 1942 Chairman of the Board of Daimler-Benz AG, had not forgotten the success which had been achieved with the Benz 8/18 hp. He constantly pushed his designers to build more reasonably-priced cars meeting Mercedes-Benz standards. The 130 model (W 23) fulfilled this requirement. It was presented in March 1934 at the International Automobile and Motorbike Exhibition (IAMA, in German) in Berlin. At the time of its unveiling, it was not only the smallest series production passenger car, the first rear-engined car and the first four-cylinder model from Daimler-Benz, but also the first German rear-engined car to be mass-produced, not counting various microcars. Officially it never bore the ‘H’ as part of its model designation.

The 130 model was based on a completely new design. An original brochure from the time summarises the aspirations for the vehicle: ‘The design of the Mercedes-Benz 130 model has undoubtedly been one of the most interesting tasks which the automotive industry has ever had to solve: to create a car which combines the driving character­istics of a larger swing axle vehicle, the spacious comfort of a modern mid-size car and the operating costs of a small car.’

The vehicle caused a stir and almost gave rise to the expectation of being bigger on the inside than on the outside – yet it did not disappoint. It had an amazingly spacious interior, not much smaller than the six-cylinder Mercedes-Benz 170.

The water-cooled 1.3-litre four-cylinder engine was a new design with vertical valves and an updraught carburettor, producing 19 kW at 3400/rpm and capable of a top speed of 92 km/h. As such the vehicle was even slightly faster than the 170 model. Its shape, which for the time was considered streamlined, was perfectly appropriate.

Mercedes-Benz supplied the 130 model as a two-door Saloon and also as a two-door Cabriolet-Saloon. For special official purposes, versions were also available in the form of an open touring car and a ‘Kübelwagen’ (bucket seat car). In addition, there had also been plans to offer the bare chassis for special bodies, however there is no evidence that this was actually implemented.

A disadvantage which is often cited in the case of rear-engined cars is their handling, which can be heavy due to the weight distribution – cornering too fast can lead to oversteer, causing the rear to slide forward. There is no question that this tendency does exist, given the laws of physics, and in general it can occur in the rear-engined cars of all manufacturers. Contemporary road tests of Mercedes-Benz vehicles examined this tendency and although there were some criticisms, they did say that drivers could, and should have to, brace themselves for such instances to ensure their safety in all driving situations.

The innovative 130 model did not live up to the expectations which were placed on it. Clearly it was way ahead of its time, particularly in terms of its shape which was very unusual for a Mercedes-Benz. Admittedly almost 4300 examples were built up to the beginning of 1936 – however, some 6000 units of the 170 model were built during the same period. Nevertheless, two years later it was replaced by a model with a similar basic design: the 170 H model (W 28), which was more powerful and somewhat larger, but at the same time also more expensive. The role of entry-level model was now taken over by the front-engined Mercedes-Benz 170 V (W 136), which was introduced at the same time as the 170 H model as the successor to the 170 model (W 15). The 170 V model was able to build further on the success of its predecessor to rank among the Mercedes-Benz models produced in the greatest numbers prior to 1945. Furthermore, it also formed the basis for the resumption of passenger car production after the Second World War.

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The engineer Josef Müller, who was involved in advance design, also provided some decisive input into the W 25 formula racing car of 1934, did not just content himself with the concept of the 130 model. In 1934, his drawing boards saw the creation of two extremely remarkable ideas. One was a car with a rear-mounted engine fitted across the rear axle, as well as an axle drive between clutch and transmission. The aim of this design was to have as little a rear overhang as possible. Müller’s second proposal, which also acknowl­edged the ideas put forward by Prof. Wunibald Kamm on the advantages of front-wheel drive, shifted the entire drive unit to a position at the front. Müller anticipated the better straight-line stability and larger luggage compartment. However, the concept did not make it into series production.

Mercedes-Benz 130 V (W 144)
Even while production preparations were under way for the 170 V, a new attempt was also being made at Daimler-Benz to develop a smaller vehicle. Gustav Röhr, the new head of passenger car devel­opment from 1935, planned a completely new passenger car model range based on a modular design. The smallest model was to be the 130 V model (W 144), an exceptionally advanced automobile for its time. It featured front-wheel drive and a 24 kW water-cooled four-cylinder horizontally opposed engine with a displacement of 1.3 litres. It was fitted with a five-speed transmission, the fifth gear of which was designed as the overdrive. It had a top speed of 100 km/h and as such was positioned below the Mercedes-Benz 170 V. Some 18 prototypes were made in two and four-door variants. After the unexpected death of Röhr in August 1937, the entire project was stopped in favour of established models. Perhaps the outstanding sales success of the 170 V also played a part here – by the end of 1936 alone some 12,600 vehicles had been produced, and by 1942 the total had risen to almost 73,000 units.

In addition, the powers that be also had their own project for a reasonably-priced car – the ‘Volkswagen’ (people’s car). Speaking from their political vantage point, they set a price which could only be achieved through subsidies: 995 RM. Based on real business calculations, it was not possible to achieve this. To put this into perspective at this point, we can take another price by way of comparison: in 1944, for the Volkswagen-based ‘Kübelwagen’ (bucket seat car), which in comparison to the Volkswagen saloon is an extremely simple car, the German armed forces paid 3500 RM.

At the board meeting held on 10 February 1939, Kissel remarked in a rather resigned way that ‘the appropriate authorities are opposing the repeated declarations of the Führer, that the Volkswagen will not eliminate anyone, but should create additional business’. Kissel dropped the 1.3-litre car, and with it all of the company’s own projects for a smaller vehicle, and channelled the company’s efforts into the models making up the previous Daimler-Benz ‘Mittellage’ (literally ‘central position’), as it was called, meaning the medium-size category.

Source: Daimler AG

The Stuttgart-based company – whose own domains have traditionally comprised product segments occupied by the luxury and upper mid-range classes – has also enjoyed repeated success in applying its innovation and development expertise in the lower range segments for more compact, lower-priced vehicles too.

Not every example of the smaller passenger car on which the engineers and designers worked survived through to the production stage, however. This is down to a variety of different reasons which make telling this chapter in the story of the compact car all the more interesting.

Carl Benz, alongside Gottlieb Daimler, is not just the inventor of the automobile. In 1894, he also introduced the small, light ‘Velo’ model: some 1200 units of this vehicle were produced, making it the first volume produced vehicle in automotive history.

In 1911, Benz & Cie. then launched the 8/18 hp model, which was not only more reasonably priced than its predecessor, the 10/18 hp, but also represented an early example of ‘downsizing’. Compared for example with the Benz 18 hp of 1905, the four-cylinder model delivered the same output but with a displacement which was almost 40 per cent less. The 8/18 hp model was therefore more efficient and also helped to save on tax – the luxury car tax intro­duced in 1906 was based on engine displacement. In 1911, the ‘Daimler-Motoren-Gesellschaft’ (DMG) also launched a model designated as the 8/18 hp: the Mercedes 8/18 hp, just like the Benz 8/18 hp, also became a commercial success.

At the start of the 1920s, during the period after the First World War, the focus once again fell squarely on compact, reasonably-priced vehicles. As a result, DMG built the 6/25 hp supercharged passenger car, specifically designed as a compact and relatively reasonably-priced vehicle – yet the large-scale distribution of what was a technically sophisticated car failed to come about due to its price. A further attempt came in 1926 with the founding of Daimler-Benz AG, a company into which both Benz & Cie. and DMG were merged. This was a vehicle with a displacement of 1.4 litres, created in 1926 under the internal designation W 01. It was shelved, however, just like the 5/25 hp model which was produced as part of a trial series production run in 1928.

Nevertheless, success was with the 170 model (W 15), on the other hand. The inexpensive and technically innovative entry-level model celebrated its premiere in 1931 – and was a tremendous success in terms of sales. In fact the W 15 played a large part in ensuring Daimler-Benz successfully overcame the difficult economic times of the early 1930s.

Even before the W 15 model series was introduced, the engineers and technicians at Daimler-Benz once again embarked on the task of developing an even more reasonably priced and compact entry-level model as part of the Mercedes-Benz passenger car range. The result was the rear-engined Mercedes-Benz 130 (W 23), introduced at the beginning of 1934. It was considered to have a groundbreaking, modern design; nevertheless, it was unable to establish itself in the market, no doubt partly due to its shape which was rather unusual for a Mercedes-Benz. Two years later it was replaced by the 170 H model (W 28), which was more powerful and somewhat larger, but at the same time also more expensive. The role of entry-level model was now taken over by the front-engined Mercedes-Benz 170 V (W 136), which was introduced at the same time as the 170 H model as the successor to the 170 model (W 15). The 170 V model was able to build further on the success of its predecessor to rank among the Mercedes-Benz models produced in the greatest numbers during the period prior to 1945. Furthermore, it also formed the basis for the resumption of passenger car production after the Second World War. Immediately after the War too, the company’s thoughts once again turned to producing smaller cars. Several vehicles were created, in some cases only on the drawing board, but some interesting configurations emerged. Things then became more definite in the 1950s with the announcement of the W 122 and W 118/W 119 model series, which due to corporate policy reasons however were not launched on the market.

In 1982, all of the planning finally came to fruition with the intro­duction of the so-called Mercedes-Benz compact class (W 201 model series), which was initially available in the form of the 190 and 190 E models. With the W 201, the Daimler-Benz engineers were credited with having developed a smaller vehicle with all of the interior values of the Mercedes-Benz brand. Since its second generation, the W 202 model series introduced in 1993, the compact class has been known under the name C-Class, which has continued the great success story of the ‘190’ model.

The line-up of smaller vehicles also includes the NAFA (from the German ‘Nahverkehrsfahrzeug’) short-distance vehicle of 1982, a groundbreaking concept based on a history of ideas which to some extent have been used in the two-seater smart car, now also a product of Daimler AG.
In 1997 the A-Class (W 168) then celebrated its market launch. Here the engineers succeeded in accomplishing quite a feat by bringing onto the market a vehicle incorporating the typical characteristics of a Mercedes-Benz, such as comfort and safety, in a body with more compact dimensions. As such, it represents a brilliant coup in the history of Daimler AG, forming part of an exciting chapter in the story of both the company and its technology. Following the major facelift which took place in 2001, it became a small family comprising different body variants – a concept which was continued in a modified form in the successor model series, the 169.

Building on the A-Class, in 2005 the B-Class then made its debut which, due to its dimensions and price structure, filled the gap between the A-Class and the C-Class. In conjunction with the R-Class, in 2005 Mercedes-Benz defined the new segment of the sports tourer. New customers were addressed with offerings comprising powerful engines, dynamic handling and pronounced space and ride comfort, combined with an interior offering a high level of variability.

Source: Daimler AG

Fan­gio drove to a total of five For­mula 1 world titles in vehicles from four different manufacturers. There was something very special about his relationship with Mer­ce­des-Benz though. He had already been working as a dealer for the Stuttgart-based brand in Argen­ti­na since 1951. And following the end of his racing career, he became President of Mer­ce­des-Benz Argentina S.A. in 1974. He died in Bue­nos Aires on 17 July 1995.

It was at the French Grand Prix on 4 July 1954 that Mer­ce­des-Benz made its first ever appearance with the new Silver Arrows from the W 196 R series. The victor at the Reims circuit was Juan Manuel Fan­gio, who had been world champion in 1951 and finished second in 1950 and 1953. The Argentinean was already aged 43 at the time, making him older than many of the other drivers in the field. He had furthermore suffered a serious accident in the 1952 season.

Yet far from being a fabulous finale to his career, Fangio’s win for Mer­ce­des‑Benz at the wheel of the W 196 R marked the start of an extraordinary success story. During 1954 and 1955, Fan­gio lined up on the starting grid for the Mercedes-Benz team for a total of 19 Formula 1 and touring car races, recording ten wins and a number of other impressive results.

Fan­gio was born to Italian immigrants on 24 June 1911 in the small country town of Balcarce in Argen­ti­na – seemingly a very far cry from a future career as a five-time Formula 1 world champion. But the youngster, who did an apprenticeship as a mechanic, was inspired by his fellow countrymen’s passion for motor racing. He came into contact with the local racing driver scene at an early age, gained some experience at the wheel himself and learned how to rebuild vehicles for racing. In 1932, he opened his own car workshop, and four years later Fan­gio competed in his first race in a converted Ford ta­xi.

After the end of World War II, Fan­gio made the switch from rebuilt standard passenger cars to thoroughbred racing cars, and entered the international racing arena. In 1950, he came second in the World Championship driving for Alfa Romeo, before going on to win his first world title for the Ita­lia­n car maker in 1951. 1951 also marked the start of Fangio’s close ties with Mer­ce­des-Benz, however, as it was the year he opened a sales outlet for the Stuttgart brand’s cars in Bue­nos Aires. And it was not long before he was sitting behind the wheel of a Silver Arrow for the first time; in Feb­ruary 1951, Mer­ce­des-Benz came over to Argentina, bringing with it three overhauled pre-war W 154 racing cars for a guest race appearance. Fan­gio was on the starting grid for the “Premio Pre­si­dente de la Nación Juan D. Perón”, along with Karl Kling and Her­mann Lang. However, the Silver Arrows were unable to reach their top speed on the modern circuit with its many chicanes, and Fan­gio only managed to finish third.

During the 1952 season, when the World Championship was switched to Formula 2, Fan­gio suffered a serious accident in Monza. He spent the remainder of the year convalescing from his injuries, most notably from one he sustained to his spine. He was already back in the racing seat in 1953 though, when he finished second in the World Championship with Mase­rati.

International motor racing was made all the more spectacular in 1954 by the return of Mer­ce­des-Benz to the grand prix arena. Racing director Alf­red Neu­bauer signed the Argentinean driving ace as the captain of the racing team. The Stutt­gart­-based outfit had been developing the W 196 R racing car for the new Formula 1 season since 1953. It was powered by a 257 hp (189 kW) inline eight-cylinder engine with a displacement of 2.5 litres, desmodromic valves and direct petrol injection. Apart from the Streamliner version, a clas­sic For­mula racing car with exposed wheels was also created. The new Silver Arrows were not ready for the start of the season, so Fan­gio still competed in a Mase­ra­ti in the first three races. At that time, the Formula 1 World Championship consisted of just a drivers’ title. The constructors’ championship was only contested from the 1958 season onwards.

On 4 July 1954, Fan­gio lined up for his first ever grand prix in a Mer­ce­des‑Benz: exactly 40 years after Mer­ce­des driver Chris­tian Lau­ten­schla­ger drove to victory in Lyon, the Stutt­gar­t team returned to the fray at the French Grand Prix in Reims. Fan­gio took the chequered flag ahead of teammate Karl Kling. The apparently effortless switch from Mase­rati to the W 196 R once again underlined Fangio’s immense ability to adapt: ever since taking part in the tough endurance races in his home country, he seemed to be able to extract the very best from every vehicle. It was this vir­tu­oso impro­vi­sational skill that led to victory for the Argentinean time and time again.

The 1954 season turned into a great tri­umph for Mer­ce­des‑Benz and Fan­gio: he followed up his victory in France with further wins in Germany (Nür­burg­ring), Switzerland (Bremgarten) and Ita­ly (Monza). Fan­gio was crowned Formula 1 world champion for the second time, with almost double the points of his nearest rival. The Argen­ti­nean dominated the 1955 season in similar fashion, winning the grand prix races in Argen­ti­na, Bel­gi­um, the Netherlands and Ita­ly, and finishing second behind teammate Stirling Moss at the British Grand Prix.
Other exceptional performances by Fan­gio during this season included second spot at the Mille Mig­lia, driving solo in a Mer­ce­des-Benz 300 SLR (W 196 S). Winner Stirling Moss, on the other hand, was accompanied by a co-driver, Denis Jenkinson, as was most of the field.

Following Mer­ce­des‑Benz’s withdrawal from motor racing at the end of the 1955 season, Fan­gio went on to win two more world championship titles with Fer­rari (1956) and Mase­rati (1957). The following year, the Argentinean called an end to his racing career at the age of 47. In 1974, he assumed the post of Pre­si­dent of Mer­ce­des-Benz Argen­tina S.A. His five Formula 1 world championship titles remained a record until his death in 1995, which was not surpassed until Michael Schu­ma­cher achieved the feat in 2003.

Today, tributes to Juan Manuel Fan­gio include five identical life-size bronze sculptures depicting the exceptional racing driver together with the W 196 R. They can be found in front of the Mer­ce­des-Benz Museum in Stutt­gart, outside the Mer­ce­des-Benz headquarters in Bue­nos Aires, as well as at the Nür­burg­ring, Monza and Mona­co circuits.

There is also a Fangio Museum in Balcarce that is run by a local association. Featuring numerous vehicles and other exhibits, it is dedicated to the racing driver’s whole life story.

Juan Manuel Fan­gio: races for Mer­ce­des-Benz

The vehicles
The W 196 R
The Mer­ce­des-Benz W 196 R Formula 1 racing car built for the 1954 season was designed around the criteria laid down for the new Grand Prix formula by the CSI (Commission Spor­tive Inter­na­ti­o­na­le): a displacement of 750 cubic cen­ti­me­tres with a supercharger or 2500 cubic cen­ti­me­tres without, no restrictions on fuel composition, race distance of 300 kilo­me­tres with a minimum race duration of three hours.

The Streamliner ver­si­on was completed first, because the season opener in Reims was suited to very high speeds. This was followed by a vari­ant with exposed wheels. This classic-style grand prix car was then also made available with shorter wheelbases for the second season in 1955: the original 2350-mil­li­me­tre car from 1954 was joined by racers with wheelbases of 2150 and 2210 mil­li­me­tres. The shortest vari­ant was ideal for the twists and turns of the city circuit in Monaco.

The space frame was light and strong, while the chassis – featuring a torsion-bar suspension and a new single-joint swing axle at the rear, as well as huge, turbo-cooled dup­lex drum brakes which were initially mounted centrally on the inside – broke with convention and to good effect. It was powered by an inline eight-cylinder engine (displacement of 2496 cc) with direc­t injection and desmodromic valve control (positive closing without valve springs) and an output of 256 hp/188 kW at 8260 rpm in 1954 and 290 hp/213 kW at 8500 rpm in 1955. The drive unit was incorporated into the frame’s structure tilted at an angle of 53 degrees to the right in order to lower the centre of gravity and reduce the size of the frontal area. Top speed was in excess of 300 km/h.

The 300 SLR
The Mer­ce­des-Benz 300 SLR motor racing car was partially based on the engineering of the successful grand prix racer, but was given the body of a road racing car. It scored some major successes in 1955, thereby adding to the brand’s stardom. Its internal designation of W 196 S was already an indication of its close kinship to the grand prix Sil­ver­ Arrow of the time.

Its engine, whose capacity had been increased to 2982 cubic cen­ti­me­tres by increasing the bore by 2 mil­li­me­tres and the stroke by 9.2 mil­li­me­tres, was the most advanced version of the inline eight-cylinder unit from the Formula 1 car. The recommended rev speed, power output and fuel tank capacity varied depending on the nature of the upcoming race, to span the spectrum between sprint (such as the Eifel Race at the Nür­burg­ring over 228.1 kilo­me­tres) and mara­thon (such as at Le Mans).

The wheel suspension of the W 196 R, with double wishbones at the front and a swing axle at the rear, had been adopted with hardly any modifications. The sports car’s space frame, weighing just 60 kilo­grams, was derived more from the 300 SL from 1952, comprising an elaborate framework made up of pipes 25 mil­li­me­tres in diameter with a wall thickness of 1 mil­li­me­tre, particularly around the low-set flanks and the sturdier struts in the vicinity of the suspension. The more unusual solutions used on the 300 SLR included a remarkably effective airbrake at the rear. It was raced at Le Mans and at the Swedish Grand Prix in Kristianstad.

With an output of as much as 310 hp (228 kW), the motor racing car was capable of top speeds beyond the 300 km/h mark.

Source: Daimler AG

The latest historical research suggests that the inventor of the automobile was born in a guesthouse at Rheinstrasse 22 in the Mühlburg district of Karlsruhe. The place of his birth had remained previously unknown. However, the house no longer exists, having been knocked down in the 1950s to allow for the widening of Rheinstrasse. The site is today occupied by a department store with adjoining car park. It is planned to erect a small memorial to the inventor in the direct vicinity of the site.

Carl Benz was born on 25 November 1844. His birth was recorded in the church register under the Germanised surname of his mother, Josephine Vaillant: Carl Friedrich Michael Wailand. It was not until one year later, on 16 November 1845, that Carl’s mother married his presumed father, Johann Georg Benz, in the Catholic parish church of St. Stephan. His mother worked as a maid in Karlsruhe from 1833 up until two months before the birth of her son.

This latest evidence is the result of exhaustive new research conducted by the municipality of Karlsruhe, which involved a search of the relevant church registers by the historian Dr Peter Pretsch , director of the local municipal museum at the Municipal Archive and Historical Museums section. Piece by piece, the names of the godfathers revealed a chain of clues: Karl Axtmann, a master shoemaker, and Michael Kramer, a “burgher, innkeeper and brewer”. Axtmann was a relative, because Carl Benz’s paternal great-grandmother was called Axtmann. It is assumed that Axtmann was instrumental in obtaining accommodation for the heavily pregnant Josephine Vaillant at the guesthouse owned by Michael Kramer at Rheinstrasse 22. As home births were the norm in those days, it is reasonable to conclude that this was the place where Carl Benz was born. Kramer’s guesthouse was later given the name “Stadt Karlsruhe”.

After their wedding, Josephine and Johann Georg Benz moved with their child to Erbprinzenstrasse 13 in Karlsruhe – another finding to emerge from the latest research, discovered in this case with reference to the 1846 street register. Benz was an engine driver with Baden Railways. Being required to perform his work in the open cabs of the steam locomotives of those days, he contracted pneumonia, from which he died in the summer of 1846 – not quite two years after the birth of his son. Thereafter, his widow provided board and lodging in Karlsruhe to students from the polytechnic school in order to finance her son’s studies.

Carl Benz first attended the scientific grammar school in Karlsruhe. Aged 15, he passed the entrance examination for the polytechnic school on 30 September 1860. Four years later, on 9 July 1864, he successfully completed his studies, after which he began work as a mechanic. Having moved to Mannheim in connection with his work, he married Bertha Ringer on 20 July 1872. In 1885 h e built his first petrol-engined automobile, a three‑wheeler, for which he filed a patent application on 29 January 1886 (German Imperial Patent No. 37.435). The patent specification may be considered the birth certificate of the automobile. Carl Benz died on 4 April 1929 in Ladenburg. Consequently, he lived long enough to witness the triumph of his invention – in contrast to Gottlieb Daimler, who died as early as 1900.

Source: Daimler AG

Caracciola achieved an average speed of 101.1 km/h in the race from Brescia to Rome and back. It was the first time that the Mille Miglia – traditionally dominated by Italian drivers – had been won by a foreigner in a foreign car and the first time that a driver’s average speed exceeded 100 km/h. The Mercedes-Benz driver received a gold medal from the King of Italy and a cup from the Automobile Club of Germany in recognition of his victory.

Three years later, Caracciola described that Mille Miglia in his first autobiography Rennen – Sieg – Rekorde (Races – Victory – Records), in which it was clear the race had a left a deep and lasting impression on him: “1,600km on dusty country roads, passing gorges and ravines … around horrible corkscrew bends and snake-like passages; through cities, towns and villages and again along dead-straight roads at an average of 150, 160, 170km … one night and then another day.”

Italian drivers seemed to hold the advantage: they knew the route and, since some makes had almost 50 cars on the starting grid, they had countless depots and mechanics positioned along the course. Mercedes-Benz was unable to offer such resources at that time, and Caracciola in fact had to enter as a private team that simply received support from the company. Due to the impact of the international economic crisis, Mercedes-Benz’s official team was unable to join the line-up in Italy in 1931.

But Caracciola rose to the challenge: “I sat behind the wheel for 16 hours, we thundered across the length and breadth of Italy for 16 hours, following the beam of our headlights through the night, driving into the blinding glare of the spring day.” The race was full of uncertainties: where was Mercedes-Benz in the field of more than 100 drivers? Even on the final leg, Caracciola did not know that Tazio Nuvolari had dropped out or that he had overtaken Giuseppe Campari.

At the finish line, he was welcomed by the jubilant Mercedes-Benz racing team manager Alfred Neubauer with news of his win: “Neubauer was beside himself, leaping about and dancing for joy. What was going on …? I didn’t understand … not yet … but then it dawned on me: I had won the Thousand Miles – the first and so far [1934] only time that a foreigner has won in a foreign car.”

The torture was worth it, he had topped the overall standings. Fans and experts alike were overwhelmed by the German driver’s victory over his experienced Italian rivals. But Caracciola did have some experience of the route by 1931. After all, the year before he had secured a category victory in the Mille Miglia (achieving sixth place in the overall standings) with Christian Werner as his co-driver, when he had driven an SSK model.
The Mercedes-Benz SSKL model (Super-Sport-Kurz-Leicht or super-sport-short-light) that Caracciola drove in 1931 was the last version to be developed of the six-cylinder compressor sports car from Mercedes-Benz. The SSKL was only built as a two-seater racing car. Its in-line six-cylinder engine with a 7-litre cubic capacity produced 240 bhp (177kw) without and 300 bhp (221kw) with the compressor. The car’s maximum speed was up to 235 km/h. But the SSKL was not just strong in Italy, and Caracciola drove it to victory in the Eifel Race, the German Grand Prix and the Avus Race in 1931. He also took five wins in five races to defend his title in the sports car category of the European Hill Climb Championship.

The race: the ‘Thousand Miles’ of Italy
Mille Miglia – the 1,000-mile race through Italy – was one of the major competitions in European motor sports in the middle of the 20th century. This long-distance race was held between 1927 and 1957. But the history of the Mille Miglia, which started and finished in Brescia, began even earlier – and is still continuing today. The first car race on the Brescia–Cremona–Mantua–Brescia course took place on 11 September 1899 – regarded as the forerunner of the Mille Miglia.

However, the actual Mille Miglia was launched in 1927 when a group of automobile enthusiasts from the Brescia area planned to organise a long-distance race to Rome and back, covering a total distance of 1,000 miles. At the first race on 26 March 1927, 77 drivers competed – all of them from Italy. It was won by Ferdinando Minoia, followed by two victories by Giuseppe Campari and a win by Tazio Nuvolari in 1930. Campari and Nuvolari would be major rivals of Caracciola in 1931.

The new race quickly attracted a great deal of attention in Europe, where motor racing was extremely popular. As a result, Mercedes-Benz took part with its powerful compressor cars from 1930 onwards. Between 12 and 13 April 1930, Rudolf Caracciola at the wheel of a Mercedes-Benz SSK took sixth place in the overall standings and won his category. The average speed was 92.8 km/h. His epoch-making victory came the next year in 1931.

After the Second World War – and a break from motor racing for Mercedes-Benz that had begun in 1939 – Rudolf Caracciola took part in the Mille Miglia for a final time, driving a Mercedes-Benz 300 SL and crossing the finish line in fourth place. The duo of Karl Kling and Hans Klenk took second place – an impressive success in the competitive debut of the new 300 SL racing car (W 194). Caracciola was delighted with the technological advances made between the SSKL from 1931 and the 300 SL from 1952: “I was overjoyed to drive a 1,000-mile race without any trace of tiredness, despite the twelve-year break. The car was so easy to drive. The steering was gentle and precise. It was great to race in such a luxurious sports car … Dear me, what a difference to the thumping, dancing steering wheel of my 2,000kg Mercedes sports car with which I had won the Mille Miglia in 1931 on stony, dusty roads. It made it clear what progress had been made in car manufacturing.”

However, Caracciola was not the one to secure Mille Miglia glory for Mercedes-Benz in this era; instead, it was British driver Stirling Moss, three years later: In May 1955, Moss and his co-driver Denis Jenkinson won the Italian marathon race in a Mercedes-Benz 300 SLR, achieving an average speed record of 157.65 km/h, which still holds today. In second place was Moss’s team mate Juan Manuel Fangio, who crossed the finish line about half an hour later and also in a Mercedes-Benz 300 SLR.

Serious accidents resulted in the Mille Miglia being dropped as a road race after the 1957 season. The modern eponymous event has taken place in the form of a regularity rally for vintage cars since 1977. Cars that enter must be of a model type that took part in the race up to 1957. Mercedes-Benz is therefore well represented in the event with racing, sports and touring cars from various epochs. The 180 D model has also entered the ‘Mille Miglia Storica’: the diesel was one of the successful cars in the 1955 road race and took first place in the diesel category.

Source: Daimler AG

Strictly speaking, however, the pedigree of the SLK stretches back even further – to the 190 SL, a vehicle which automotive enthusiasts were already dreaming about in 1955 as the economic upturn was starting in the Federal Republic of Germany. When the SLK appeared as a series-produced car in 1996, it not only caused a stir on the road but also established a new market segment which has since grown by leaps and bounds. With the steel vario-roof, which transforms the roadster into an all-weather coupé within a matter of seconds, the roadster has been and still is the role model for many open-top cars. The success of the SLK has exceeded all expectations: to date, well over half a million owners have been delighted with their purchase of an SLK Roadster.

The 190 SL – a new star in the automotive firmament in 1955
With the SLK, Mercedes-Benz continued its roadster tradition which stretches back a long way. Its direct ancestor is considered to be the 190 SL, which owes its existence primarily to the perseverance of Maximilian Edwin Hoffman. The enterprising American with Austrian roots was importing European cars into the USA as early as 1946, and in doing so demonstrated infallible instinct and tremendous flair. In 1953 he urged the executive board of Daimler-Benz to build a more affordable sports car, in addition to the 300 SL, for the American market. As an elegant sports car from a well-known company featuring an exciting design at a low price, the 190 SL was designed to charm the Americans.

After a development period of just five months, on 6 February 1954 the 190 SL celebrated its world premiere in New York, alongside the legendary 300 SL “gullwing”.

Unlike the 300 SL, the 190 SL was not designed as a thoroughbred sports car but rather as a sporty, elegant two-seater touring and utility vehicle. Its chassis was the shortened frame floor assembly from the 180, combined with the single-joint swing axle with lowered centre of rotation, as used in the 220. The front-wheel suspension, including subframe design, came from the 180 / 180 D models. The 190 SL was driven by a newly developed four-cylinder engine with a displacement of 1.9 litres, overhead camshaft and output of 105 hp. Depending on conditions it could therefore reach a speed significantly exceeding 170 km/h, and accelerated from 0 to 100 km/h in 14 seconds.

Series production started in May 1955. The 190 SL was available as a roadster with soft top as well as a coupé with removable hard top, with or without a soft top as an option. A broad range of prominent social figures chose this elegant sports car to complement their image, including Grace Kelly and Frank Sinatra, who drove a 190 SL in the film “Ten Thousand Bedrooms”.

The Mercedes-Benz 190 SL was built up until 1963. The clearest indication of just how much loved and successful the 190 SL was is demonstrated by the production figures: between May 1955 and February 1963, no less than 25,881 cars left the assembly lines in Sindelfingen – far in excess of the initial aspirations.

Two studies for the new type of roadster
Against this historical backdrop, it seemed only logical some decades later to revisit these considerations: would it not perhaps be appropriate for the SL-Class Mercedes-Benz models, now firmly established in their own right, to be joined by a younger brother? After all, Mercedes-Benz had launched an entirely new product initiative, to which a compact roadster could lend fresh emphasis by drawing attention to the sporting heart of the Mercedes-Benz brand.

An appropriate acronym for this newcomer was swiftly coined: SLK. In German, these three letters stand for the car’s characteristic properties – sporty, lightweight and short – and, given the great sporting successes of Mercedes-Benz back in the 1920′s and 1930′s, they have an almost mystical resonance.

In Turin in April 1994, roadster enthusiasts were able to gain a first glimpse of how Mercedes-Benz believed a compact roadster should look. A brilliant silver showstopper with a distinct aura of spartan sportiness sent the trade professionals into raptures. Bruno Sacco, Head of Design for the brand at the time, made it clear what the company’s aim was: “We are exhibiting a forward-looking roadster study which delivers a unique synthesis of purist motoring pleasure with all the safety features for which Mercedes cars are renowned”.
To meet these requirements, some formal individuality was called for. The SLK study reflected this thanks to its compact dimensions and some evident highlights. Short overhangs at the front and rear, as well as a distinctive wedge shape, embodied the enjoyment to be had from a hands-on driving experience. And the two “power domes” on the bonnet, running parallel to the direction of travel, were acknowledgement of the originator of all SL’s dating from the 1950s. The SLK study revealed a lot of gleaming metal. Only 20 percent of the interior was covered, and the high-tech cockpit was dominated by bold shapes and high-quality materials.

To find out just how seriously the people in charge at Mercedes-Benz were taking this SLK project in its earliest days, one needs to look no further than the Paris Motor Show held in September of the same year. Here the company unveiled its second study, this time with a vario-roof and in the form of a customised version in blue, with blue-tone leather and a range of additional luxury accessories such as automatic transmission, air-conditioning system, power windows, a hi-fi sound system and much more besides. This enabled Mercedes-Benz to demonstrate convincingly the breadth of appeal and the potential inherent in a compact roadster.

The SLK sets the trend before going into series production
Then the automotive enthusiasts started to wait. Many viewed the SLK as a very auspicious prospect indeed. Mercedes-Benz had done the unexpected and demonstrated that a small and relatively inexpensive roadster was capable of offering a great deal of motoring pleasure while still being an absolutely serious and down-to-earth car in terms of safety and quality. This meant that the roadster studies had already opened up a new market niche, making the SLK a trendsetter even before series production had begun.

By 1996 everything was in place: the series production version of the new SLK, designated internally as the R 170, was launched at the Turin Motor Show. Especially high levels of interest were shown in the fully-lowering steel vario-roof, which substantively backed up the SLK claim to being a car for all weathers. Using an intelligent electro-hydraulic system, the entire roof folded down into the boot in just 25 seconds, leaving the owner free to roam under an open sky.

The SLK also fielded a convincing range of other qualities. Take safety for example: two fixed roll-over bars behind the seats protected occupants from injury if the car should overturn and, in conjunction with the exceptionally robust A-pillars, delivered a very high level of safety even when these Mercedes-Benz cars are driven with the top down.

Engines from 136 to 354 hp
The sporting talent of the SLK was unleashed by two engine variants: a 2 litre four-cylinder engine with a power rating of 100 kW (136 hp) and a supercharged 2.3 litre engine, also a four-cylinder unit, delivering 142 kW (193 hp). In early 2000, the two litre engine was also fitted with a belt-driven supercharger, boosting power to the rear axle to a new level of 120 kW (163 hp). The choice of engines was broadened by the arrival of two six-cylinder models, the 160 kW (218 hp) unit for the SLK 320 and the 260 kW (354 hp) powerplant in the SLK 32 AMG.

The evolution of the SLK continues
In February 2000, Mercedes-Benz substantially upgraded the level of equipment for its roadster and incorporated innovations such as the Electronic Stability Program (ESP) and a six-speed manual transmission into its standard equipment package. In visual terms, a new bumper and side skirts gave the car an even more dynamic appearance. All the attachments and door handles were painted to match the vehicle body, to enable the whole car to present an image of a unified whole in terms of both colour and form. New tail lights, stainless steel trim on the exhaust tailpipe and a painted radiator grille gave the SLK design an even more commanding identity.

Even more driving pleasure with the second generation SLK
In the spring of 2004, the second generation of the SLK (internal model series designation: R 171) was launched – offering more sportiness and dynamism, and even more driving pleasure. Thanks to powerful engines, a newly developed chassis, direct steering and a precise six-speed shift mechanism, the second generation of the SLK provided an even more responsive driving experience. As a world first, Mercedes-Benz introduced the AIRSCARF neck-level heating system. At the touch of a button, it generates warm air which flows from the head restraints. This now meant that drivers of the SLK were able to enjoy open-top driving and the open-air roadster experience all year round, even when outside temperatures dropped. The operating mechanism for the vario-roof was modified. The rear window now rotated in its frame, so that its concave side was uppermost when the roof was folded. This enabled the luggage capacity to be increased.

True to the principle of ongoing development, in 2008 the SLK underwent
a comprehensive facelift. The most significant visual changes included redesigned front and rear sections and also a carefully modified interior with new instrument cluster and three-spoke sports steering wheel. The distinctive dynamic character of the two-seater was brought to the fore to particularly good effect in the SLK 350 courtesy of a high-revving V6 sports engine producing 224 kW (305 hp) along with an optional Direct-Steer system. In addition, despite their significantly increased performance, all of the engines were more economical in terms of fuel consumption.

The new SLK once again sets standards
The new SLK which will be presented in January 2011, and designated internally as the R 172, will follow in these same footsteps. Partly thanks to new engines with the ECO start/stop function, the roadster consumes significantly less fuel, thus demonstrating that achieving pure driving pleasure while maintaining a clear conscience when it comes to the environment do not necessarily have to be conflicting principles. The new SLK combines nimble-footed sportiness with stylish comfort, a striking sports car design with absolute suitability for everyday use, and top-of-the-range performance with exemplary ecology. In addition, a unique series of safety equipment enables the SLK to assume the role of benchmark in this segment. Standard equipment also includes the ATTENTION ASSIST drowsiness detection system.

Mercedes-Benz will also be the world’s first automotive manufacturer to offer the panoramic vario-roof with MAGIC SKY CONTROL as an optional extra. With this innovation, the transparent glass roof can be darkened in a matter of seconds at the touch of a button. Other options include a Dynamic Handling package with continuously variable damping incl. Direct-Steer and the Torque Vectoring Brake, or the Intelligent Light System with various lighting functions. Thanks to such a rich array of technical innovations, the SLK will once more set the standard in its class.

Model history: the Mercedes-Benz SLK
1994
- In April, Mercedes-Benz displays the compact roadster as a study vehicle at the Turin Motor Show
- In September a second study vehicle is unveiled, this time with vario-roof and in the form of a customised version

1996
World premiere of the SLK at the Turin Motor Show

2000
The SLK undergoes a comprehensive facelift

2004
World premiere of the second generation of the SLK at the Geneva Motor Show

2008
Facelift for the second generation of the SLK

2011
Third generation of the SLK

Source: Daimler AG

The automatic transmission even featured as standard in the Mercedes-Benz 300 SE which was presented in August 1961. This opened a special chapter in the brand’s success story running throug 125 years of the automobile.

Mercedes-Benz decided to build its own automatic transmission in keeping with the company’s commitment to maintaining its innovative strength – a constant factor throughout the brand’s history: as the automatically shifting transmission has a decisive influence on the character of an automobile, the development engineer striving for the best can only be content with a solution tailored precisely to the brand’s own vehicles.

Instead of a torque converter the new transmission had a hydraulic start-up clutch, which offered the advantage of reduced power loss. The secondary four-speed planetary gear system comprised two planetary sets, three multi-disc clutches and three band brakes.

Automatic gear-shifting in the history of Mercedes-Benz
Mercedes-Benz had already produced vehicles with partially automated gear shifting prior to this development. The model 770 (model series W 07), which went down in automotive history as the “Grand Mercedes”, featured semi-automatic vacuum-power shifting for the overdrive gear, for example. This function of the Maybach overdrive transmission was controlled via a lever on the steering wheel.

And while the Mercedes-Benz engineers were already at work on the company’s first automatic transmission, the “Hydrak” hydraulic automatic clutch was presented in the summer of 1957. The new automatic clutch was initially available as an optional extra for the 220 S and 219 models. The system comprised a hydraulic start-up clutch, a conventional single-plate dry clutch for engagement and disengagement during gear-shifting and a freewheel to bypass the hydraulic clutch.

Genuine automatic transmissions also emerged at this time, initially produced by external suppliers. From the autumn of 1955, Mercedes-Benz offered the model 300 c with a three-speed converter transmission from Borg-Warner, for example.

1961: the first automatic transmission from the inventor of the automobile Mercedes-Benz introduced its first automatic transmission to be developed in-house on the model 220 SEb in April 1961. The automatic transmission came as an optional extra for this model, while featuring as standard on the model 300 SE of model series 112 which was presented in August 1961.

Further Mercedes-Benz models subsequently benefited from this refined, convenient and efficient transmission of the available engine power. From August 1962 the four-speed automatic transmission was available for the 220 and 220 S models subject to an additional charge of DM 1400, for example.

The four-speed automatic transmission was also optionally available for the Mercedes-Benz 230 SL Roadster (W 113) as of 1963 – a first among the sports cars from Mercedes-Benz. Finally, the prestigious Mercedes-Benz 600 limousine was available exclusively with the automatic transmission as of 1964.

75 years after Carl Benz invented the automobile, the launch of the automatic transmission marked a further milestone in the brand’s history and the starting point for an outstanding series of innovations. The engineering and technology relating to automatic gear-changing has been subject to ongoing development at Mercedes-Benz since 1961.

The automatic transmissions have been built at the Hedelfingen factory since November 1961. The 100,000th automatic transmission for passenger cars from Mercedes-Benz was produced here in 1966, the output subsequently topping 500,000 by 1971 and one million in 1975. This development provides a clear illustration of the automatic transmission’s success. The registration figures reveal a similar picture: by 1964, just three years after the automatic transmission from Mercedes-Benz was unveiled, 14.5 percent of all passenger cars delivered by the brand were fitted with this type of transmission, the figure even rising to over 20 percent when the petrol engines are considered on their own. This share rose continually, until automatic and transmissions each accounted for around 50 percent of delivered cars in the mid-1980s.

The future of the automatic transmission
A new automatic transmission from Mercedes-Benz was premiered in the S-Class saloons of the 116 model series in August 1972. It was designed as a converter transmission, rather than an automatic clutch. The transmission with hydraulic torque converter was initially offered as an optional extra. The 450 SE and 450 SEL models which were available as of 1973 featured this automatic transmission as standard.
The Roadster and Coupé models of the 107 SL series and mid-range models of the 114 and 115 model series (“Stroke/8”) were also available with the converter transmission. The high-powered models with V8 engines were initially fitted with a three-speed transmission, while other engine variants were combined with a four-speed automatic transmission. As of 1980, four-speed transmissions were standard for all passenger cars from Mercedes-Benz which were delivered with automatic transmissions.

The automatic transmission was always a key focus of engineers’ and developers’ efforts to make automobiles from Mercedes-Benz yet more comfortable, sporty and economical. An important step in this process was the development of five-speed automatic transmissions, for example, which were premiered in October 1990 as optional extras for the 300 E-24 model, the 300 E-24 Estate, the 300 CE-24 Coupé (all belonging to model series 124) and the 300 SL-24 (R 129).

The NAG automatic transmission set new standards when it was presented in 1995. This five-speed automatic transmission from Mercedes-Benz with electronic control and torque converter lock-up clutch offered unprecedentedly smooth and easy gear shifting. The light and comparatively compact transmission was initially introduced for the models fitted with V8 and V12 engines. From the summer of 1996 it became available for numerous classes of vehicle from the comprehensive passenger car programme.

Among the exceptions was the A-Class: the compact rear end and the special arrangement of the drive unit necessitated the development of special transmissions for the A-Class. The front automatic transmission was duly introduced as an optional extra for the A-Class (W 168) as of the summer of 1998. This transmission offered five speeds, had an electronic control system and was the shortest and lightest five-speed automatic transmission in the world, measuring 315 millimetres in length and weighing in at 68 kilogrammes.

As an alternative for the A-Class, Mercedes-Benz offered the ACS automatic clutch system, which operated along the same lines as the Hydrak from 1957: when the driver took his foot off the accelerator and moved the shift lever, the system identified the wish for a gear change and opened the clutch by means of an electric motor.
In the next generation of the A-Class (model series 169) and in the B-Class (T 245) the front automatic transmission was replaced by a continuously variable automatic transmission (CVT) which performed gear shifting unnoticeably.

In 2003 Mercedes-Benz presented the world’s first standard production seven-speed automatic transmission for passenger cars, the 7G-TRONIC. It was initially introduced as a standard feature for the E 500 (W 211), S 430 and S 500 (W 220), CL 500 (C 215) und SL 500 (R 230) models, replacing the previous five-speed automatic transmission.
In addition to reducing fuel consumption substantially, this transmission also performed faster, smoother and easier gear-shifting than previous automatic transmissions. This innovation highlighted the Stuttgart-based automobile brand’s technology leadership once again.
The 7G-TRONIC, designed for high continuous torque of 700 Newton metres, represents the fifth generation of automatic transmissions from the Mercedes-Benz brand. The popularity of the automatic transmission developed in tandem with its technical evolution. By 2004, the automatic transmission was standard for the S-Class, while around 88 percent of E-Class customers ordered their vehicles with an automatic transmission and the corresponding share for the C-Class stood at around 65 percent – with the underlying trend remaining upward.

Another seven-speed option was the innovative AMG SPEEDSHIFT MCT 7-speed sports transmission which was jointly developed by engineers of the high-performance AMG brand and Mercedes-Benz. It was premiered in the SL 63 AMG (R 230), which was launched in April 2008. This transmission employed a compact, wet start-up clutch instead of the conventional torque converter. In conjunction with the double-declutching and RACE START functions, the resultant direct connection to the powertrain gave rise to an extremely emotional and highly dynamic driving experience. The abbreviation “MCT” stands for multi-clutch technology and alludes to the fact that gear-shifting is performed exclusively by clutch elements. This high-tech transmission was designed for high torque values and maximum engine speeds of up to 7200 rpm. Its extremely light weight of 80 kilogrammes was made possible by the use of the lightweight material magnesium, among other measures.

In 2010 Mercedes-Benz presented the 7G-TRONIC PLUS seven-speed automatic transmission in the new generation of the CL-Class (model series 216). This transmission operates even more smoothly, quickly and economically than the first generation of the 7G-TRONIC. Its efficiency has been optimised by measures such as an engine connection offering a further reduction in converter slip and markedly diminished gear friction losses. The various innovations enable engine speeds to be lowered when the vehicle is in ECO mode, making a crucial contribution to reduced fuel consumption.

A particularly innovative development is the automatic transmission in the F 800 Style research vehicle which was presented in 2010: in the hybrid version of the technology flagship, the Mercedes-Benz engineers have integrated the entire high-torque hybrid module rated at around 80 kW (109 hp) into the housing of the 7G-TRONIC seven-speed automatic transmission. With solutions of this ilk, Mercedes-Benz is boldly moving forward the brand’s long traditions of technical expertise in the field of automatic gear-shifting.

Source: Daimler AG

1932 – First production light truck with a diesel engine
The Lo 2000 was the world’s first light truck to be fitted with a diesel engine as standard. Daimler-Benz AG introduced it in 1932 at the Geneva Motor Show. It was powered by the new 3.8-litre prechamber diesel OM 59. This innovative vehicle design was a response of Daimler-Benz to the difficult economic situation following inflation and a world economic crisis. Customers had a high opinion of this economical and light truck.

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The letters “Diesel” on the radiator next to the Mercedes star became a symbol mainly of heavy goods transport in the 1930s. Whereas the diesel engine’s share of the power plants of big trucks already reached 90 percent in Germany in 1931, and trucks of five tons payload and more were fitted exclusively with diesel engines after 1934, the compression-ignition engine was much slower establishing itself in the light truck segment. The new OM 59 of 1932 was an important argument for diesel technology: the engine was less than half the size of the OM 5, but was nearly as powerful. And it gave the Lo 2000 a top speed of 65 km/h; in 1932 this definitely sufficed to have it called an express delivery van.

1933 – Semitrailer tractors from Daimler-Benz
The semitrailer tractors built in Gaggenau from February 1933 on also profited from the success of the Lo 2000. With the LZ 4000, LZ 6000 and LZ 8000 series (four, six and eight tons) the diesel truck model range of Daimler-Benz continued to grow. In the mid 1930s Daimler-Benz built trucks with petrol engines almost only for export.

High-speed, light diesel engines proved a key to the success of the semitrailer tractors: relatively small-volume engines with rated speeds of 2000 rpm and displacements between 3.8 litres (40 kW/55 hp) and 7.4 litres (70 kW/95 hp) powered the semitrailer tractor. In 1938 a tractor for ten tons payload was added; its six-cylinder diesel developed 74 kW (100 hp). The advantage of uncoupling tractor and semitrailer was used by the buyers of tractors not only in the haulage sector: semitrailers were even supplied equipped as buses – this configuration went into the vernacular as “Tatzelwurm” (a mythical Alpine dragon).

1935 – 10,000th Mercedes-Benz commercial vehicle with diesel drive
Nine years after the merger of Benz & Cie. and Daimler-Motoren-Gesellschaft in 1926, the diesel engine was playing an increasingly important role in the commercial vehicle sector for Daimler-Benz AG: in Gaggenau the 10,000th commercial vehicle of the brand featuring a compression-ignition engine was delivered to a customer on 6 April 1935.

The engine range was correspondingly diversified, including engines for light and heavy-duty trucks with four and six cylinders as well as engines for urban buses.

1940 – Birth of the 300 engine series
A new era in diesel technology for commercial vehicles began at Mercedes-Benz during the Second World War: in 1940 the engineers of the Stuttgart brand took up work on an entirely new generation of diesel engines, the 300 series. The first prototype was the in-line six-cylinder OM 302, parallel to which the designers worked on the four-cylinder OM 301 unit.

Characteristics of the new engine were its compact dimensions and innovative components, for example a seven-bearing crankshaft and leaded bronze bearings with steel backings for the main and connecting rod bearings. Production commenced in 1942, but work on the 300 engine series could not be resumed until after the war.

1949 – OM 312 engine
On the basis of the OM 302, at war’s end Mercedes-Benz Development resumed work on a modern commercial vehicle diesel engine. The condition was that the new unit had to be produced on machines on which Daimler-Benz manufactured a licensed version of the Opel Blitz during the latter war years and until 1949. This Mercedes-Benz L 701, as the vehicle with its wooden cab was called, the first truck of the Stuttgart brand after the war, was still powered by a petrol engine. On the other hand, under the bonnet of the first post-1945 heavy-duty truck, the L 4500, was the tried and tested OM 67/4 in-line six-cylinder diesel, which developed 82 kW (112 hp) at 2250 rpm.

The diesel engine in the new L 3250 truck presented in May 1949 at the Hanover Trade Fair was now the OM 312, the first member of an extremely successful engine family. Passing through numerous stages of development, the 300 series would be the backbone of the medium-duty commercial vehicle diesel engine range from Mercedes-Benz for more than 50 years. In its first version the OM 312 in the L 3250 already developed 66 kW (90 hp) at 2800 rpm.

A 1949 brochure underscored the advantages of the new design and left no doubt as to the importance of the new truck for the commercial vehicle range of the brand: “The water-cooled, flexible six-cylinder diesel engine with an output of 90 hp and featuring controlled cylinder wall temperature and oil temperature is a particularly interesting new technical creation with its average fuel consumption of 14.4 litres per 100 km. Outstanding performance characteristics, highest operating reliability, tremendous economic efficiency, simple operation and thriftiest consumption, combined with excellent handling qualities and safe roadholding are the essential features of the new L 3250.”

In the heavy-duty segment too, in 1950 a 300-series engine superseded the diesel technology which still dated from the 1930s: the Mercedes-Benz L 6600 was powered by an OM 315 8.3-litre in-line six-cylinder, which was good for 107 kW (145 hp) at 2100 rpm.

1953 – Exhaust gas turbocharger for fire-fighting vehicles
The new generation also furnished a basis for technical innovations during the following years. Mercedes-Benz took an important step to boost performance by introducing the exhaust-gas turbocharger for commercial vehicle diesel engines. In a TLF 15/36 TA pump water tender, the Stuttgart company presented the first diesel engine which utilised the energy of flowing exhaust gases for charging the cylinders. The type OM 312 A engine (the A stands for Abgasturbolader = exhaust-gas turbocharger) developed 85 kW (115 hp), 18 kW (25 hp) more than the naturally aspirated basic engine.

But there had already been a few turbocharged commercial vehicle diesel engines from Mercedes-Benz before that: from 1948 the Esslingen-based Eberspächer company had been offering a suitable turbocharger as a retrofit kit for the OM 312. However, turbocharged commercial vehicle diesel engines did not gain broad acceptance until around 30 years later.

1957 – The 20,000th Unimog diesel
The new diesel engines from Mercedes-Benz not only were a success in trucks and cars. Special-purpose vehicles like the Unimog (“Universal-Motorgerät” for universal working machine) also were equipped with the diesel power unit. From the start of Unimog production to November 1957, 20,000 diesel engines were built for this powerful all-wheel-drive vehicle alone.

Originally, the diesel engines of the Unimog were identical with those of the Mercedes-Benz diesel passenger cars. In May 1963 the Unimog U 406 came out on the market with a 48 kW (65 hp) OM 312 under its bonnet. This was Mercedes-Benz’s answer to the increasing demand for a high-powered variant of the special-purpose vehicle with the wide range of applications. The Unimog no longer saw use only in agriculture, but long since had proved its mettle in municipal service, as a fire-fighting vehicle, with the military and in other areas.

1963 – New model designations based on weight and output
The designations existing for the different truck models in the Mercedes-Benz range in the 1950s said nothing about the output of the engine used in each truck. The letters only indicated the basic configuration (conventional or cab-over-engine vehicle) and body. In 1963, therefore, Daimler-Benz decided to abolish the old nomenclature. During the following months, the letter and number combinations which we know today were introduced. The last two digits stand for one tenth of the engine output in horsepower (rounded off). Before that the gross vehicle weight in tons (rounded off) is stated. Thus, the heavy-duty all-wheel-drive truck LA 2620 of 1964 has a permissible GVW of 26 tons and an output of roughly 200 hp (147 kW). Actually, the OM 346 engine developed 154 kW (210 hp) at 2200 rpm from its six cylinders with a total displacement of 10.8 litres.

1964 – Direct injection for commercial vehicle diesel engines
The OM 352 engine introduced at the 1964 Geneva Motor Show by Mercedes-Benz was the first direct-injection diesel for commercial vehicles. Direct injection results in lower consumption and higher output. Initially, however, the engines did not run as smoothly as their prechamber cousins. Particularly if single-hole injection nozzles were used with central combustion in a spherical combustion chamber, extremely loud noises and a high peak pressure were generated. Multi-hole injection nozzles and flat combustion chambers in the pistons were better still for fuel consumption, but likewise led to loud combustion noises and high peak pressures. The Mercedes-Benz design engineers ultimately decided to use a four-hole injection nozzle positioned almost dead-centre in the cylinder. However, it sprayed the fuel into the cylindrical combustion chamber at an angle of about 30 degrees. The fuel spray was directed at the wall of the combustion chamber; a swirl duct in the cylinder head provided for the necessary turbulence of the diesel mist in the cylinder. The ignition pressure in the direct-injection diesel rose to around 80 bar compared with 60 bar in the prechamber engine.

The operating noise of the direct-injection diesel had been sharply reduced by the time the engine was ready for production in 1964. In the car sector though, for the time being the classic prechamber diesel with its refined characteristics remained the power plant of choice for Mercedes-Benz. In the commercial vehicle sector, by contrast, the first direct-injection diesel was received very well. For buyers of trucks and buses, not only the boost in power counted. The better efficiency compared with the prechamber power plants reduced the thermal load on the engines; they proved to be particularly reliable. A pleasant side effect of the reduced load on the engine oil: the servicing intervals for oil changes were extended to 18,000 kilometres.
A four-cylinder injection engine, the OM 314, also was brought out in 1964. The first units of the new model had a displacement of 3.8 litres and developed 59 kW (80 hp) at 2800 rpm. The four-cylinder engines were used in light cab-over-engine trucks, vans, and special-purpose vehicles like the Unimog.

1968 – Turbocharging for the direct-injection diesel
A number of customers increasingly asked for a Mercedes-Benz diesel engine with fuel injection and exhaust-gas turbocharger. The turbocharger was supposed to provide the power necessary mainly for journeys through mountain regions. For where the atmosphere gets thin, boosting the volume of air in the combustion chamber gives rise to an especially sharp increase in output.

Initially the OM 352 A was intended for use in snow cutters. Following successful road testing the turbocharged unit was also installed in trucks. The new engine premiered in the L 1413, where the turbocharged injection engine developed 115 kW (156 hp). The use of improved turbochargers from Eberspächer, Garrett (Honeywell) and KKK (Kühnle, Kopp & Kausch) made this high-powered compression-ignition engine even more reliable.

1969 – The 100,000th commercial vehicle diesel engine
In the Mercedes-Benz Mannheim works, an anniversary was celebrated in January 1969: the 100,000th diesel engine for commercial vehicles built in the plant on the River Neckar came off the assembly line.

1969 – Hybrid research on diesel-engined buses
Mercedes-Benz displayed the first prototype of the OE 302 hybrid electric bus at the 1969 International Motor Show in Frankfurt/Main. The aim of optimizing the propulsion system of line-service buses in this project was mainly to reduce their emissions in downtown areas: battery current served to power the buses in the sensitive zones of city centres; on highways and in less densely populated city districts the serial hybrid drive changed to the diesel engine. In the serial hybrid system, however, the compression-ignition engine did not act directly upon the wheels, but supplied the electric traction motor with energy via a generator.

The successor to the OE 302 was presented in 1978 at the “transport 78” trade show in Munich: the OE 305 hybrid electric bus again had an electric traction motor which a diesel engine powered via the generator. The heavy batteries notwithstanding, the capacity of the drive system was designed so that the bus attained the performance of a comparable diesel-powered O 305 urban bus. Despite the high load on them, the storage batteries survived an average of 800 recharging operations. In the course of 1979 a total of twenty OE 305 hybrid electric buses took up local public transport service in the cities of Stuttgart and Wesel. By 1983 the vehicles had covered more than 1.3 million kilometres.

In 1979 Daimler-Benz also introduced a second hybrid bus: besides the standard diesel engine, the Duo Bus or dual-powered bus was equipped with an electric motor which was supplied with current by an overhead cable. Whereas the electric motor was used in the city, in the country the bus operated on its diesel drive. Before the end of 1979, three of the vehicles commenced trial operation in regular service in Esslingen. During the next few years more than 50 of these vehicles would be used internationally in regular service.
These test vehicles of the 1970s presaged the part that the diesel drive would play in advanced hybrid concepts for passenger cars after the year 2000. Other bus concepts with innovative drive systems were the diesel-electric O 405 GTD dual-powered bus (1986) and the diesel-electric O 405 GNTD bus (1994). This low-floor articulated bus had a diesel engine that powered a generator that supplied electric energy for the wheel hub motors.

1970 – New OM 400 engine series
A new engine series for heavy-duty trucks came out on the market in 1970. The 400 family of Mercedes-Benz diesel engines made its debut in the new LP 1632 as a V10 engine with a displacement of 16 litres and an output of 235 kW (320 hp) at 2500 rpm. The new units were the designers’ response to a proposed law intended to speed up over-the-road freight transport: in 1968 the German Federal Minister of Transport, Georg Leber, introduced a bill stipulating that from 1972 on new vehicles must have an engine output of 6 kW (8 hp) per ton of gross combination weight.

Medium-duty and light trucks, which are more likely to be used in short-radius distribution work and pull trailers less frequently than their heavyweight brothers, were not so much affected by this regulation. But for long-distance trucks and tractors and other heavy-duty commercial vehicles, the output of the 300-series engines was no longer adequate under the conditions set by the new laws. From 1969 Mercedes-Benz thus set about developing the new engine generation.

The veil was lifted on the OM 403 with diesel direction injection in 1970. Together with the engine, the LP 1632 truck presented another innovation – a tilt cab. This appreciably simplified the servicing of the engine in a COE truck and invalidated a major argument in favour of conventional trucks. In 1972 the bigger engine was complemented by the OM 402 V8 diesel, with 12.8 litres displacement and 188 kW (256 hp) output at 2500 rpm. For medium-duty trucks, the OM 401, a V6 diesel with 9.6 litres displacement and 141 kW (192 hp) at 2500 rpm, followed in 1975.

1970 – Assembly of commercial vehicle diesel engines in Iran
Iranian Diesel Engine Manufacturing Company (IDEM) in Tabriz, Iran, began assembling diesel power units for commercial vehicles in 1970. Daimler-Benz had owned a stake in the company since 1969. Engines of the 300 family were built there: around 180,000 units of the OM 314, OM 352 and OM 352 A engines were produced in the first 30 years of this cooperation.

The commercial vehicle diesels from Mercedes-Benz conquered the world during this decade: in 1979 Mercedes-Benz awarded licenses for the 300 and 400 series to Industrial Development Company of South Africa (IDC). Diesel engines of Stuttgart origin were built and adapted to various vehicles and pieces of equipment in the engine plant of Atlantis Diesel Engine (ADE) north of Cape Town.

1975 – The one-millionth commercial vehicle diesel engine from the Mannheim plant
In Germany, too, the manufacture of commercial vehicle diesels was running at full swing. In 1975 a V6 diesel from the OM 401 series became the one-millionth commercial vehicle diesel engine to be built at the Mercedes-Benz plant in Mannheim. The 141 kW (192 hp) engine was donated to the city of Mannheim, which installed it in a Mercedes-Benz fire truck.

1980 – Turbocharged and intercooled OM 422 LA
As early as the mid-1970s Mercedes-Benz began developing commercial vehicle engines which featured an intercooler in addition to the exhaust-gas turbocharger. Cooling reduces the temperature of the air compressed by the turbocharger, thus increasing the oxygen content. This permits obtaining higher power in engines with the same technical data: the OM 422 A V8 diesel developed 243 kW (330 hp) with 14.6 litres displacement, whereas its intercooler-equipped brother introduced in 1980 developed an output of 276 kW (375 hp).

This OM 422 LA engine was the first commercial vehicle engine from Mercedes-Benz to have an intercooler. It was followed in 1982 by a 300 series engine, the OM 362 LA, with the same technology and an output of 141 kW (192 hp) at 2600 rpm. 300 series engines like this were built in large numbers mainly for export.

1987 – The 500,000th engine of the OM 400 series
Within 17 years, 500,000 engines of the OM 400 series were built. The anniversary engine originated in Mannheim in January 1987. From the original OM 403 V10 engine, meanwhile, various V6 and V8 drive units had emerged whose power output in production trucks ranged from 140 to 320 kW (190 to 435 hp). A special heavy-duty hauling variant of the V10 engine even boasted 368 kW (500 hp).

1996 – Debut of new engine families 500 and 900
Together with the new Actros heavy-duty truck, in 1996 Mercedes-Benz introduced a new, innovative engine family. The diesel power plants of the 500 series made their debut with a V6 engine, the OM 501 LA (230 kW/313 hp – 315 kW/428 hp) and a V8 engine, the OM 502 LA (350 kW/476 hp – 420 kW/571 hp). Equipped with exhaust-gas turbocharger and intercooler, the engines featured individual unit pumps and attained their maximum torque at 1080 rpm. While the V6 had one turbocharger for the entire engine, the V8 was distinguished by one turbocharger for each of the two cylinder banks.

Together with the 500 series Mercedes-Benz introduced the new 900 series of in-line diesel engines for the new Atego truck family, comprising mainly light and medium-duty vehicles. The four-cylinder OM 904 LA developed between 90 kW and 125 kW (122 hp and 170 hp), the six-cylinder OM 906 LA delivered 170 kW or 205 kW (231 hp or 279 hp).

With the two new engine families, plus the 457 series borrowed from South American production in 2001 for the new Axor family, Mercedes-Benz soon covered the entire commercial vehicle spectrum with different ultramodern diesel power units. The engines are perfectly matched to the other components of the drive system. An individual drivetrain can thus be put together from different modules. This results in an extraordinary variety of models and specification options.

1998 – Diesel-electric drive system in the Cito midibus
In 1998 Mercedes-Benz introduced the Cito urban midibus. The innovative low-floor vehicle had a diesel-electric drive system. An OM 904 LA diesel engine with an output of 130 kW (177 hp) served to drive a generator. The generated electric power was fed into the electric traction motor. Thanks to this drive technology, the Cito excelled with smooth and continuous acceleration. This driving characteristic cannot be obtained with a purely mechanical drivetrain.

The unit consisting of diesel engine, generator and electric motor was installed in the rear of the vehicle and called a power pack. Mercedes-Benz developed the system together with Siemens. The Cito was built from 1999 to 2003. In 2000 it won the distinction of “Bus of the Year 2001.”

2003 – More torque for the OM 500 series
All variants of the OM 500 were revised in 2003. The V6 and V8 engines of the Actros got slightly higher power ratings. But most of all the torque of most of these diesel engines was markedly increased. The engines’ ease of servicing also was improved with wear-free materials and extended servicing intervals of as much as 150,000 kilometres in long-haul operation.

2004 – 450 kW (612 hp) in the Actros Black Edition
This special edition of the Actros, limited to 250 units, is equipped with the OM 502 LA engine, which develops 450 kW (612 hp) at 1800 rpm from a displacement of 16 litres, making this the first Mercedes production truck to clear the 600-hp hurdle.

2006 – The 500,000th reconditioned commercial vehicle engine
A V8 diesel of the 500 family became the 500,000th reconditioned diesel engine for Mercedes-Benz commercial vehicles in 2006, coming off the assembly line at the Mannheim plant. Genuine reconditioned engines or factory-reconditioned components from Mercedes-Benz are the ideal solution for providing commercial vehicles with a virtually new drive system. Reconditioned engines are typically used for trucks and buses which run up high mileages in a short time – the so-called mileage millionaires. But also for vehicles with expensive special bodies and correspondingly high residual value, the replacing of the engine suggests itself when the original unit shows weaknesses.

In a reconditioned engine, not only all defective and worn-out parts are replaced, but all design changes, innovations and improvements made since original manufacture are incorporated into the unit. With that, the reconditioned component gets an entirely new identity, recognisable by the reconditioned-unit model plate. And Mercedes-Benz gives the same warranty on it as for a brand-new component.

Reconditioned engines are available for the 500, 900, 457, 300 and 400 series. The V-engines of the heavy-duty 500 series are the heart of the Actros and are also premium engines operating in high-quality touring coaches like the Travego. The 900 series powers the Atego, Vario, Cito, Citaro and Unimog vehicles; the 457 family operates in the Axor and Citaro. But even for the older series, the 300 and 400, production of which was discontinued, there are still replacements available. For the most part, these engines are reconditioned using original production equipment. They are available then, for example, to the fans of vintage Unimog vehicles.

Engine reconditioning has a long tradition in Mannheim: since 1949 the factory has been dismantling commercial vehicle engines, completely overhauling them and returning them as good as new to customers. The 200 employees in engine reconditioning overhaul some 5000 units annually. This requires detailed knowledge: there are more than 2700 different engine variants on the list.

2007 – Citaro bus with innovative diesel technology
In 2007, Mercedes-Benz presented the first prototype of a Citaro with diesel-electric hybrid drive to the public. The developers set themselves ambitious targets in that this diesel-electric serial hybrid drive is a technologically highly sophisticated system. It permits zero-emission operation on battery power alone. The drive configuration is equally advanced: it is installed in a Citaro G articulated bus and comprises four wheel hub motors which drive the central and rear axles. At this point in time, the Citaro Hybrid was the only vehicle to offer this combination.

In the serial Citaro Hybrid, the diesel engine no longer serves as a permanent drive unit but powers the generator which supplies the amount of electricity required at any point in time. There is therefore no mechanical connection between the diesel engine and the driven axles – a characteristic feature of serial hybrid drive. This creates new degrees of freedom in the design of the passenger compartment. The electricity produced by the generator is stored in maintenance-free lithium-ion batteries which are mounted on the roof of the Citaro. This battery technology stands out for a particularly high energy density and high storage capacity. The batteries generate 170 kW (231 hp), and their weight of 450 kilograms is comparatively low. They are fed with energy not only by the diesel-powered generator but also by the brakes – a process known as recuperation.

Downsizing is one of the major advantages for the technology of the particularly sophisticated serial hybrid in the Citaro: instead of the OM 457 hLA six-cylinder in-line engine with its very large displacement of twelve litres normally used in the articulated bus, the compact OM 924 LA is installed in the hybrid bus. It develops an output of 160 kW (218 hp) from a displacement of 4.8 litres. As a result, engine weight is reduced from around 1000 to just 450 kilograms. The use of the compact engine has been made possible by the fact that the diesel engine does not serve as prime mover of the Citaro Hybrid bus. It does not have to generate peak output, for instance, and can therefore be operated in the narrow engine speed band in which the highest fuel economy and lowest emissions are ensured. For this reason, the engine’s torque characteristics were adapted to its – partly stationary – operating conditions in the hybrid bus for optimised levels of emissions and fuel economy.

2007 – BlueTec diesel technology as a recipe for success
After the successful introduction of the long-distance Actros truck with BlueTec technology in early 2005, the company launched the models from the Atego and Axor truck series as well as Actros construction-site vehicles with BlueTec diesel technology onto the market in 2006. To ensure that the stringent limits of forthcoming emission norms are safely undercut and to achieve clear advantages in terms of fuel economy at the same time, since 2007 the company is consistently using SCR (Selective Catalytic Reduction) technology in all its commercial vehicles for the European market. SCR reduces pollutants in the exhaust gas by up to 80 percent and at the same time lowers the fuel consumption to a measurable extent.

SCR is based on the injection of an aqueous urea solution (AdBlue) into the exhaust flow which together with the catalytic converter reduces nitrogen oxides (NOx) by around 80 percent. This is the most effective method in existence for reducing nitrogen oxides in diesel engines. In 2005 trucks and buses with BlueTec already met the particularly stringent Euro 4 and Euro 5 emission standards that would apply to the production of all engines beginning in the autumn of 2006 and 2009, respectively.

Tried and tested diesel engines as the basis
The basis of the first revolutionarily clean BlueTec diesels are the tried and tested 500- and 900-series engines. In the Actros the V6 power plant OM 501 LA in its weakest version develops 235 kW (320 hp) at 1800 rpm. The engine achieves its maximum torque of 1650 Newton metres at 1080 rpm. In addition to turbocharger and intercooler, the engine has a central, high-set camshaft, fully electronic engine management with single-cylinder injection pumps, and centrally arranged eight-hole nozzles providing an injection pressure of up to 1800 bar.

The most powerful unit of the 500 series is the OM 502 LA with 16 litres displacement, an output of 440 kW (598 hp) at 1800 rpm and torque of 2800 Newton metres at 1080 rpm. Injection is based on the same principle as in the V6 unit, except that seven-hole nozzles are used. Both V-engines have a four-valve-per-cylinder design. Whereas in the V6 version the rated outputs remain largely the same and a new top V6 variant with 350 kW (476 hp) and maximum torque of 2300 Newton metres has been added, BlueTEC generally gives the existing V8 engines a higher output. The most powerful OM 502 LA now develops 440 kW (598 hp) at 1800 rpm and has maximum torque of 2800 Newton metres.

The 900-series engines with BlueTec likewise cover the entire range of variants previously offered as Euro 3 engines. The OM 904 LA in the basic version as water-cooled in-line four-cylinder with three valves per cylinder develops 95 kW (129 hp) at 2200 rpm. The engine features a turbocharger, intercooler and fully electronic engine management with nine-hole injection nozzles which achieve injection pressure ratings of up to 2000 bar. The maximum torque of 500 Newton metres is available at 1200 to 1600 rpm.

The most powerful BlueTec engine of the Atego is the OM 906 LA, a water-cooled in-line six-cylinder with three valves per cylinder. The technical details are similar to those of the four-cylinder unit; however, this engine gets 210 kW (286 hp) at 2200 rpm with 6.4 litres displacement. This is good for torque of 1120 Newton metres at 1200 to 1600 rpm.

The OM 457 LA and the OM 906 LA in the Axor also give a good account of themselves as environment-friendly BlueTec engines. The water-cooled in-line six-cylinders in four-valve-per-cylinder design work with a turbocharger and intercooler, a central, high-set camshaft, fully electronic engine management with single-cylinder injection pumps, and centrally arranged seven-hole or nine-hole nozzles providing an injection pressure of up to 2000 bar. In its basic version the Euro 4 OM 906 LA develops 188 kW (256 hp) at 2200 rpm. The engine attains its torque of 970 Newton metres at 1200 to 1600 rpm. The most powerful version of the Euro 5 OM 457 LA engine with its twelve litres displacement develops 315 kW (428 hp) at 1800 rpm, and the torque of 2100 Newton metres is available at 1100 rpm.

In the past, the Euro 1 through to Euro 3 emission norms always required compromises as combustion processes designed for low particulate emissions and high fuel economy inevitably produced larger quantities of nitrogen oxides – and vice versa. The external SCR exhaust gas aftertreatment eliminated this conflict of goals caused by thermodynamic laws and permitted the next generation of engines from the 900 series to be developed for both low consumption and low particulate emissions. The success of this technology speaks for itself: as per July 2007, as many as 80,000 BlueTec trucks were already operating on our roads – the majority of these already comply with the Euro 5 emission norm which would come into force in October 2009. And in 2008 more than 160,000 vehicles with BlueTec were in operation – with a great many more to come.

The continuous improvement of this technology by the Mercedes-Benz engineers guarantees the sustained success of BlueTec in the commercial vehicle field. In October 2010 Fleet Transport Magazine honoured this achievement with the presentation of the “Green Commercial of the Year“ award to the Atego BlueTec Hybrid.
The platform of this short-radius distribution truck with hybrid drive is the Atego 1222 L EEV. The basic vehicle satisfies the EEV (Enhanced Environmentally Friendly Vehicle) standard and operates on German roads toll-free. Its compact and light four-cylinder diesel engine with a displacement of 4.8 litres develops 160 kW (218 hp). It is paired with a water-cooled electric motor with a peak output of 44 kW (60 hp) which is supplied with power by high-energy, high-capacity lithium-ion batteries.

The electric motor is arranged behind the internal combustion engine and clutch but in front of the transmission. In this set-up, engine and motor can drive the truck individually or in combination. This architecture (parallel hybrid drive) permits moving off under electric power, recuperation, boosting with the electric motor, and optimisation of the diesel engine’s characteristics. The driving power of the diesel engine is cut in by means of the clutch between the diesel engine and the electric motor. Up until then the internal combustion engine serves exclusively to power the auxiliary units. The result is not only a clear-cut reduction in fuel consumption and exhaust emissions by up to 15 percent, but also lower noise emissions.

A fleet of 50 Atego BlueTec Hybrid will be delivered to German customers in the short-radius distribution sector at the start of 2011 in order to prove the workaday suitability of this important technology of the future. The vehicles will be included in the “Electric Mobility Advancement Programme” of the German Federal Ministry for Transport, Construction and Urban Development.

Source: Daimler AG

In 2010 all CDI BlueEFFICIENCY E-Class models with six-cylinder diesel power plant, for example, already meet the EU5 emission standard, and the BlueTEC model E 350 BlueTEC with urea injection even meets the future EU6 standard. Diesel-hybrid vehicles like the E 300 BlueTEC HYBRID and the Atego BlueTec Hybrid truck now represent a further step towards the future of the diesel engine.

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BlueTec for commercial vehicles and BlueTEC for passenger cars
The introduction of BlueTEC in the passenger car in 2006 marks the beginning of a new era in Mercedes-Benz diesel-powered cars. The engineers of the Stuttgart-based brand initially developed this visionary emission control system for commercial vehicles, introducing it to the market in 2005. BlueTec (it is spelled differently if referring to cars or commercial vehicles) immediately set standards for the reduction of the pollutants in diesel exhaust gas, which promptly was reflected in success on the market: in February 2006 the 10,000th BlueTec truck with Euro 5 engine was delivered to a customer. And in 2008 more than 160,000 vehicles with BlueTec were in operation – with a great many more to come. This is a good foundation for developing BlueTEC for diesel passenger cars.

Evolution of the compression-ignition engine in the car
Considering the history of innovation of the diesel passenger car at Mercedes-Benz, the step to incorporate BlueTEC into present-day cars is only logical: the Stuttgart brand built the first diesel passenger car in 1936. 1971 saw the one-millionth car with compression-ignition engine since the Second World War roll off the assembly line. And in 1976 the C 111-II with diesel engine set standards on its record-breaking run in Nardo. The history of diesel technology is punctuated again and again by such major innovations – especially owing to the initiatives of Mercedes-Benz. Since about 1990 the pace of technological development has picked up very strongly. And this is why in 2006 BlueTEC became the latest standard of this diesel evolution.

Where the development of the compression-ignition engine into a clean and powerful drive for future automobiles can take us is shown by studies like the S-Class S 320 BlueTEC Hybrid, presented at the Frankfurt International Motor Show in 2005, which combines the low-emission diesel with an electric motor. With an electric motor integrated in the powertrain, the concept car was a “mild hybrid”, with significantly reduced fuel consumption especially in inner-city stop-and-go traffic. The diesel engine switches itself off whenever it is not required. All the modifications and features combined reduce the fuel consumption of the BlueTEC HYBRID by some 20 percent versus the comparable predecessor model. The combined output of this S-Class car is 179 kW (243 hp); the combined torque is as high as 575 Newton metres. The car accelerates from standstill to 100 km/h in 7.2 seconds, and its top sped is electronically limited to 250 km/h. Fuel consumption (New European Driving Cycle) is as low as 7.7 litres per 100 kilometres. The study made this very clear: at Mercedes-Benz the diesel has great potential as a high-tech drive of the future. And this future already was within close reach, for a few years later BlueTEC HYBRID cars were being built in series.

But for the first, in 2006 the clean Mercedes-Benz BlueTec commercial vehicles were the trendsetters for the car sector, as the highly innovative system for reducing nitrogen oxides (NOX) and other emissions also lends itself to application in passenger cars: BlueTEC reduces nitrogen oxides to such an extent that the toughest emission limits worldwide can be met.

In early 2006 Mercedes-Benz then presented BlueTEC for passenger cars as a ready-for-production package consisting of several components. The extensive optimisation of the engines and the combustion processes taking place inside them constitutes the basis of this package. With solutions like multi-hole injection nozzles, the use of the latest generation of CDI technology and other measures, the raw emissions are cut to an extremely low level. This is where the emission control system with an oxidising catalytic converter (for hydrocarbons and carbon monoxide) and a particulate filter comes in. The final stage is nitrogen oxide reduction by the BlueTEC component proper.

2006 – E 320 BlueTEC, the future of the diesel car
It’s the world’s cleanest diesel: in late 2006 the E 320 BlueTEC hit the US market as the first production BlueTEC car. The E 320 BlueTEC is an innovative model which is based on the sophisticated E 320 CDI V6 and relies on the BlueTEC technology developed by Mercedes-Benz. BlueTEC is the designation for a highly efficient method of minimizing nitrogen oxide emissions already used in commercial vehicles. In contrast to commercial vehicles, the E 320 CDI BlueTEC does not make use of AdBlue injection but reduces nitrogen oxides with a system based on an improved storage-type catalytic converter.

Three E 320 BlueTEC vehicles also took part in the 13,600 kilometre “E-Class Experience Paris – Beijing” from October to November 2006. This long-distance trip involving a total of 36 Mercedes-Benz E-Class Saloons recalled an adventurous long-distance journey organised in 1907, but which went in the opposite direction, from Beijing to Paris. Despite this major event in the important automotive market China, the E 320 BlueTEC was first put on the market in the United States.

The question may occur why the E 320 BlueTEC made its debut in the USA. One reason, of course, is the growing demand for economical and at the same time clean cars in that country, caused by rising fuel prices. But there’s yet another reason for this specific timing: “The introduction of clean diesel fuel in the USA is something we have been fighting for alongside others for a long time, and an opportunity we wish to use from Day One,” said Dr Thomas Weber, member of the Board of Management of Daimler AG responsible for Research, when the car was introduced in Las Vegas, Nevada. Modern diesel-engined cars which, in West Europe, account for more than half of new registrations annually, were unable to develop their full potential in the USA due to the excessively high sulphur content in the fuel until then. This changed at the end of 2006 thanks to the nation-wide introduction of clean diesel fuel with a sulphur content of just 15 ppm (15 cubic centimetres of pollutant per cubic metre of fuel). The so-called Ultra Low Sulfur Diesel (ULSD) would be available at up to 76,000 filling stations in the USA in a first step and thereby permit the use of BlueTEC. With this innovative diesel technology, Mercedes-Benz is also able to remain below the strictest globally applicable limits where nitrogen oxide emissions are concerned. Hence, all the preconditions for the breakthrough of modern diesel technology in the USA are fulfilled.

2007 – BlueTEC for passenger cars comes to Europe
Encouraged by the success of the E 320 BlueTEC developed for the North American market, Mercedes-Benz decided to present the E 300 BlueTEC of the 211 series as first passenger car with BlueTEC for the European market at the end of the year 2007. It easily is the cleanest diesel in its class and fully meets the requirements of the Euro 5 exhaust emission standards.

2007 – BlueTEC in studies and concept cars
Mercedes-Benz demonstrated the direction in which developments in the passenger car sector are going with concept vehicles in 2006, first and foremost the Vision GL 320 BlueTEC and the Vision CLS 320 BlueTEC. The GL has an SCR catalytic converter with AdBlue injection; the CLS, like the E-Class, features an improved nitrogen-oxide storage-type catalytic converter.

The Vision GL 420 BlueTEC presented in 2007 then demonstrated that great fuel economy and extremely low emissions can be achieved with BlueTEC – also, and in particular, in large and powerful cars. The high-performance V8 diesel engine develops 216 kW (290 hp), has a torque of 700 Newton metres and is expected to have a fuel consumption of just 9.8 litres per 100 kilometres. The car’s independent styling expresses the special status of the GL 420 BlueTEC and at the same time meets the wishes of Mercedes-Benz customers in the USA for even greater exclusiveness and individualisation. The redesigned, distinctively swept-back front end with its dominant radiator grille expresses the extraordinary performance of the V8 diesel engine in the car’s appearance and gives the car a dynamic forward thrust even when it’s stationary. These self-assured looks are enhanced by flared wheel arches, representative 21-inch wheels and lateral floorboards.

2007 – Systematic expansion of the BlueTEC model line-up
At the North American International Auto Show (NAIAS) in Detroit in January 2007, Mercedes-Benz displayed three new BlueTEC models with SCR exhaust gas aftertreatment which it built in series beginning in 2008. On this occasion, Dr. Thomas Weber had this to say: “With SCR, our clean and efficient diesel engines comply with the stringent American Bin 5 norm. This also applies to the three new V6 BlueTEC models R 320 BlueTEC, ML 320 BlueTEC and GL 320 BlueTEC which we will launch into the US market in 2008.”

In the brand’s systematic expansion of its BlueTEC model line-up, Mercedes-Benz was backed up by a J. D. Power study in 2007: “Global Outlook for Diesel” predicts a share of diesel-engined cars in new registrations of well over 15 percent in North America by 2015. The precursor is the E 320 BlueTEC which is already available in the market. With 35 miles per gallon or 6.7 litres per 100 kilometres, it is by far the most economical car in its class in the United States.

Awards for BlueTEC
The response to BlueTEC in the USA is extremely positive, as illustrated by the distinctions awarded by renowned American science and engineering journals for the BlueTEC technology developed by Mercedes-Benz at the end of 2006. Scientific American named BlueTEC as one of the 50 groundbreaking innovations in science and technology of the year 2006. Popular Science, the oldest and best-known scientific journal, included BlueTEC in “Best of What’s New”, its list of the year’s best product innovations. Ward’s Automotive Group, a leading publisher of numerous media and trade journals for the motor industry, nominated the engine of the E 320 BlueTEC for its listing of the ten best drive systems of the year 2007.
In 2007, motor editors from 22 countries elected the E 320 BlueTEC as the “World Green Car 2007” at the International Auto Show. This award recognises the role of Mercedes-Benz as pacemaker of a novel diesel technology which makes the compression-ignition engine as clean as a petrol engine.

Storage-type catalytic converter or AdBlue injection
The diesel principle has come a long way from Rudolf Diesel’s invention to the modular BlueTEC system. Time and again the company contributed decisive innovations to develop the diesel drive to its present level. Thus, the compression-ignition engine presents itself today as a high-performing and economical high-tech drive with the potential for meeting even the toughest international emission limits in the future. Not only the powerful six-cylinder power plants were to profit from this, but the state-of-the-art four-cylinder diesel engines from Mercedes-Benz as well.

Four-cylinder engine with BlueTEC
So at the Geneva Motor Show in February 2007, Mercedes-Benz for the first time presented the environmentally compatible BlueTEC emission control technology in combination with a four-cylinder engine with optimised fuel economy. The Vision C 220 BlueTEC outlines the approach to compliance with the further tightened Euro 6 emission norm which will come into force for all new vehicles throughout Europe in 2015. At an output of 125 kW (170 hp) and a maximum torque of 400 Newton metres, the Vision C 220 BlueTEC consumes 5.5 litres of diesel per 100 kilometres. This is the result of ongoing development of diesel engine technology and intelligent energy management.

Dr. Dieter Zetsche, Chairman of the Board of Management of Daimler AG and Head of Mercedes-Benz Cars, commented on this new development as follows: “The modern four-cylinder diesel engine with BlueTEC emission control is a prime example of cutting-edge technology with a safe future. With our diesel strategy, we provide the answer to the question of how fuel consumption – and thus carbon dioxide emissions – can be lowered, how all exhaust gas constituents including nitrogen oxides can be further reduced, and superior motoring pleasure can be ensured at the same time. We are convinced that the modern diesel currently represents the best and most efficient solution in this respect.”

With the Vision C 220 BlueTEC, Mercedes-Benz outlines the next steps in the BlueTEC initiative in very concrete terms – an initiative the company launched in the USA in autumn 2006. The Vision C 220 BlueTEC undercuts forthcoming emission limits – even the significantly tightened Euro 6 limits which will apply to all new vehicles from 1 September 2015. To give an idea of the reductions required, here are a few figures: compared with the currently applicable limit values, particulate emissions have to be reduced by a factor of five for compliance with the Euro 5 limits which will come into force on 1 January 2011. And according to Euro 6, the nitrogen oxide limit will be just 30 percent of the limits applicable in 2007. All Mercedes-Benz diesel cars with standard particulate filters already complied in 2007 with the particulate limits to be introduced in 2011.

TrueBlueSolutions: Mercedes-Benz shows the future of the clean automotive drive system in 2007
At the 2007 International Motor Show in Frankfurt am Main, Mercedes-Benz displayed an entire fleet of especially economical and clean automobiles with intelligently combined drive technologies – studies as well as production vehicles. They included eight BlueTEC models and seven hybrid vehicles. The motto of the whole presentation was “TrueBlueSolutions”, showing environment-friendly drive solutions for the future of the automobile.

For instance, the S 300 BlueTEC HYBRID as study of a production model for the near future featured a unique combination of BlueTEC and hybrid technology, offering a combined output of 165 kW (224 hp) and maximum combined torque of 560 Newton metres, comparable with the figures for a big-displacement petrol V8.
Also on display at the Mercedes-Benz stand: the new E 300 BlueTEC for the European market and the 320 BlueTEC models of the R, ML and GL-Class. In addition, a preview of the near-series studies C 250 BlueTEC, with the new generation of the Mercedes-Benz four-cylinder diesel engine, and E 300 BlueTEC HYBRID could be seen.

Mission: Sustainable mobility
Sustainable mobility has been a corporate mission pursued by Daimler AG for years. The company is working on low-emission and ever more economical vehicle models with great commitment. The focus is on reducing not only carbon dioxide but also all other pollutants which have to be taken into account on the road to sustainable mobility. The results of these ongoing efforts are remarkable: from 1995 through 2007, the carbon dioxide emissions of Mercedes-Benz vehicles have declined by some 20 percent, and this rate is clearly higher than the 14 percent reduction achieved by the European motor manufacturers on average. It should also be noted that no other motor manufacturer can beat this rate.

A host of technical innovations was required to achieve this reduction within the Mercedes-Benz vehicle fleet. An impressive example of this is BlueTEC technology for diesel engines. Shortly after its introduction in the passenger car it was already helping to make the Mercedes-Benz models the most efficient and cleanest diesel-engined vehicles in their respective categories.

Since 2008 these innovations also include BlueEFFICIENCY, the comprehensive vehicle fuel consumption reduction programme. The diesel engine in the CDI BlueEFFICIENCY models profits from this innovative approach: for BlueEFFICIENCY the Mercedes-Benz engineers make use of the potential in all areas of development in order to reduce weight, wind resistance and rolling resistance further and organise energy management in vehicles still more efficiently.

Thomas Weber, member of the Board of Management of Daimler AG and responsible for Group Research and Mercedes-Benz Cars Development commented on this in the summer of 2009: “Mercedes-Benz car models are very economical and clean as it stands today. Our BlueEFFICIENCY models – we will have 58 of them on the market by the end of the year – are a good example. Just how successful this concept is is shown by the new E-Class, which combines ultramodern engines and the world’s best Cd figure in this vehicle category with other pinpoint measures intended to optimise the vehicles, including lightweight design and intelligent energy management. In the sum of these efforts we attain 23 percent greater efficiency compared with the previous model.”

BlueTEC and the future: a Mercedes-Benz success story
The Mercedes-Benz diesel passenger car success story has gained new momentum owing to BlueTEC – not only in the North American market. For as of September 2009 Mercedes-Benz has been offering this now complete BlueTEC model range also in Europe: along with the new W 212 series E-Class Saloon E 350 BlueTEC, the ML 350 BlueTEC 4MATIC, GL 350 BlueTEC 4MATIC and R 350 BlueTEC 4MATIC, which had already been on sale in the USA for a year. The environment-friendly BlueTEC technology lends these SUVs additional attractiveness in Europe. In spring 2010 the G 350 BlueTEC followed. And so a genuine classic – the G-Class, a success since 1979 – meets the particularly clean 21st century Mercedes-Benz diesel drive.

The new E 350 BlueTEC features a V6 diesel engine which delivers 155 kW (211 hp) and makes maximum torque of 540 Newton metres available from 1600 rpm. The fuel consumption of this model, fitted with a seven-speed automatic transmission, is 7.0 litres per 100 kilometres (combined NEDC consumption). For the BlueTEC model the V6 engine was reengineered in detail, among other things in order to reduce the in-engine raw emissions and meet the legal requirements in regard to on-board diagnosis (OBD). The emission control system has a close-coupled oxidising catalytic converter and a diesel particulate filter positioned in the area of the firewall – this shortens the regeneration periods.

The heart of the BlueTEC system is two SCR (Selective Catalytic Reduction) catalytic converters with an upstream AdBlue® injector. Monitoring and diagnosis of the complex exhaust gas aftertreatment are handled by several sensors including a differential pressure sensor, oxygen sensor and NOX and temperature sensors. For the service fluid AdBlue® the E 350 BlueTEC gets an additional 25-litre tank fitted with a diaphragm pump, valve, pressure and temperature sensor, as well as electric heating. It prevents the 33-percent urea solution from freezing at low temperatures. Refilling of the tank should take place during regular maintenance service. Owing to this complex technology the exhaust emissions of the E 350 BlueTEC are at EU6 level.
But the efforts of Mercedes-Benz to make the diesel drive cleaner with BlueTEC are not limited to six-cylinder models: with the E 250 BlueTEC study, specifically designed for the North American market, in spring 2009 Mercedes-Benz showed a way to combine the BlueTEC technology of the E-Class with a four-cylinder with optimised fuel consumption. In the study the Mercedes-Benz combined the all-new four-cylinder diesel with BlueTEC. The result is the most economical and cleanest diesel model in this vehicle category which, with its range of as much as 44 miles per gallon (equivalent to 5.3 litres per 100 kilometres), attains a fuel efficiency better than that of most hybrid vehicles in the US market. Thanks to highly effective emission control, the E 250 BlueTEC does better than required by the American Bin-5 and ULEV emission standards, which are among the toughest in the world. At the same time, thanks to its high torque of 500 Newton metres, seven-speed automatic transmission and Lanchester balancer shaft, the refinement and performance of the four-cylinder is on a level with that of six-cylinders.

Just as much as new engines, the BlueEFFICIENCY package of the W 212 E-Class also conduces to the remarkable reduction in the fuel consumption of the diesel models, as demonstrated by the new four-cylinder diesel engine in the E 250 CDI BlueEFFICIENCY. With an output of 150 kW (204 hp) and 500 Newton metres of torque from 2.1 litres displacement it develops seven percent more output and 25 percent more torque than the current V6 diesel engine in the E 280 CDI with its displacement of three litres. At the same time it uses about 23 percent less fuel. With 5.3 litres per 100 kilometres (combined NEDC consumption) it is distinctly more economical than comparable saloons in this performance class. The CO2 emissions of the new four-cylinder diesel models come to 139 grams per kilometre or up to 24 percent below the figures for the CDI predecessors.

Engineers from all Development departments have optimised parts and components to save fuel through less weight, new design, improved function or efficient energy management. The work in the wind tunnel was highly successful. With a drag coefficient of 0.25 the new E-Class is the most aerodynamically efficient executive-class saloon in the world. It beats the previous model’s very good Cd by another four percent. The aerodynamics are improved, for example, by an automatically controlled fan louvre which regulates the flow of air in the engine compartment on demand.

Other BlueEFFICIENCY measures included newly developed tyres with up to 17 percent less rolling resistance and the energy-saving control of alternator, fuel pump, air conditioner compressor and power steering.

E-Class with new four-cylinder diesel engines
With the new generation of four-cylinder diesel power plants in 2009, Mercedes-Benz introduced the fourth generation of its tried-and-trusted common-rail direct-injection system into series production. One of its hallmarks is a 400-bar increase in the maximum rail pressure, which now stands at 2000 bar in the 220 CDI BlueEFFICIENCY and the E 250 CDI BlueEFFICIENCY. This increased pressure potential is essential for raising engine output up to 150 kW (204 hp) and maximum torque to 500 Newton metres, while distinctly reducing untreated emissions.

Newly developed piezo injectors are key components in the latest CDI engine generation. They use piezo-ceramic properties to change their crystal structure – and therefore their thickness – in a matter of nanoseconds when electrical voltage is applied. The new injectors are equipped with a stack of thin piezo-ceramic layers (called the “piezo stack”) to enable them to achieve a sufficient overall lift from the very small lift per layer. In contrast to the systems commonly used to date, this lift activates the nozzle needle directly, so that the fuel injection can be adjusted even more precisely in line with the current load and engine-speed situation – for example by means of precise multiple injections, which have a favourable effect on emissions, fuel consumption and combustion noise. Moreover, the engine runs much smoother at idle than its predecessor. Crucial to peak output and to full-load consumption (with respect to emissions) is the maximum ignition pressure – at 200 bar the new four-cylinder diesel from Mercedes-Benz is tops in the passenger car diesel engine sector.

In the new diesel engines for the E 220 CDI BlueEFFICIENCY and E 250 CDI BlueEFFICIENCY, Mercedes-Benz also realises two-stage turbocharging with demand-related control, for the first time in production passenger car diesel engines. The major advantage of this sophisticated technology is improved cylinder charging, and therefore high torque even at low engine speeds. Fuel consumption is also reduced. When the car is driven, this concept makes itself felt by harmonious driving characteristics with no turbo lag, a favourable torque curve across the entire engine speed range, great responsiveness and noticeably improved performance.
But depending on application other techniques also find use, for example in the E 200 CDI BlueEFFICIENCY, which features a single-stage variable-nozzle turbocharger. Since the engine output is smaller, a smaller turbocharger could be chosen to obtain very good drive-away characteristics.

Other special features of the new four-cylinder diesel engines include cooled exhaust gas recirculation for NOX reduction, a rear-mounted camshaft drive and the controllable water pump.

Dieter Zetsche, Chairman of the Board of Management of Daimler AG and Head of Mercedes-Benz Cars, made an altogether favourable review of BlueEFFICIENCY in March 2010, citing the current four-cylinder CDI models of the E-Class as example: “We have significantly reduced consumption and emissions with our BlueEFFICIENCY offensive. Our new models boast an excellent ratio of performance to CO2 emissions, thereby achieving an outstanding degree of efficiency.”

BlueTEC HYBRID goes into production
The presentation of the E 300 BlueTEC HYBRID, the first series-produced diesel hybrid passenger car from Mercedes-Benz, at the International Motor Show in Geneva in 2010 marks a critical new stage in the development of the diesel engine in Mercedes-Benz cars. The E 300 BlueTEC HYBRID pairs a 2.2-litre four-cylinder diesel engine developing 150 kW (204 hp) with a powerful hybrid module. Its 15 kW electric motor, positioned between the internal combustion engine and the 7-speed automatic transmission, assists the diesel engine when the car is accelerating (boost effect), although it is also suitable for driving using electric power alone. It is also used for the recuperation of braking energy in alternator mode.

The E 300 BlueTEC HYBRID consumes 4.1 litres of diesel fuel per 100 kilometres (CO2 109 grams per kilometre). The diesel hybrid will be launched as Saloon and Estate at the end of 2011.

BlueTEC and CDI BlueEFFICIENCY in the S-Class
In summer 2010 Mercedes-Benz included the first BlueTEC model of the S-Class in its range, the S 350 BlueTEC. With combined fuel consumption of just 6.8 litres of diesel per 100 kilometres (NEDC) – corresponding to CO2 emissions of 177 grams per kilometre – the new diesel model is eleven percent more economical than its predecessor. At the same time, the power output is up ten percent at 190 kW (258 hp) and torque is 15 percent higher at 620 Newton metres. The S 350 BlueTEC already complies with the emission levels which are planned for 2014 with the introduction of the EU6 standard.

The new S-Class diesel model already features Active Blind Spot Assist and Active Lane Keeping Assist, the innovations for active safety. The S 350 BlueTEC thus combines outstanding safety and high comfort with the effortlessly superior performance of an eight-cylinder vehicle and simultaneously boasts very good fuel consumption and emission values.

In autumn 2010 the S 250 CDI BlueEFFICIENCY then caused somewhat of a sensation: this S-Class Saloon is the first 5-litre car in the luxury class and the first model with a four-cylinder in the more than 60-year success story of the S-Class. The highly efficient turbodiesel achieves fuel consumption of only 5.7 litres per 100 kilometres in the NEDC cycle, which equates to CO2 emissions of 149 grams per kilometre. This makes the new S 250 CDI BlueEFFICIENCY the first vehicle in its class to undercut the 150 gram mark for CO2 emissions.

To ensure hallmark S-Class comfort, dynamically controlled engine mounts feature as an innovation in the new S 250 CDI BlueEFFICIENCY. The rigidity and damping of these mounts, which are interlinked with the engine management system via databus, alter according to engine speed, load and vehicle speed, thus preventing the transmission of unwanted vibrations and noise from the engine to the body.

With an eye to the 125th anniversary of the invention of the automobile by Carl Benz in 1886, Dieter Zetsche, Chairman of the Board of Management of Daimler AG and Head of Mercedes-Benz Cars, referred to the S 250 CDI BlueEFFICIENCY as a component part of the future of the automobile in September 2010: “The invention created by Daimler and Benz changed the world and affected virtually every aspect of daily life. Now we are inventing the automobile for the second time, and the effects will again be revolutionary.”

Source: Daimler AG

In Mannheim he devoted himself to making Rudolf Diesel’s dream reality: the compact, high-speed diesel engine as an automotive power unit. L’Orange developed prechamber injection, the pintle-type injection nozzle, the funnel prechamber and the variable injection pump – milestones on the compression-ignition engine’s way into the automobile and at the same time the basis for the first vehicle diesel engines.

A life for engine technology
Prosper L’Orange was born on 1 February 1876, in Beirut, in the then Ottoman Empire. He grew up in Germany after 1890. The boy was very enthusiastic about the technology of internal combustion engines and decided to attend the Technical University in Berlin-Charlottenburg. He passed his diploma examination cum laude and became an assistant to Privy Councilor Emil Josse in the university’s heat technology laboratory.

L’Orange went from there to Gasmotorenfabrik Deutz, where he became head of the testing department in 1906. Here he worked mainly on a diesel engine variant which did not have a compressor for air-injection of the diesel oil. He planned to transfer the principle of this internal combustion engine to smaller engines: compact units with outputs of around 26 kW (35 hp) would make ideal power plants for automobiles. However, L’Orange realised that the engine first had to be cured of the “lack of restraint of its fuel feed.” He intended to devise a solution which would enable controlling fuel atomisation, and thus combustion, more accurately than before.

Similar projects were pursued by other engineers too, but Prosper L’Orange took the most forward-looking approach with his injection pump. This precision-controlled instrument delivered fuel to the combustion chamber under 50 atmospheres of pressure. The engineer then turned to the shape of the compression space to improve the mixing of compressed air and fuel spray: in 1908 L’Orange took out a patent on a so-called afterchamber, a space before the cylinder in which air and fuel could swirl. The uncooled, spherical chamber was placed opposite the combustion chamber, with inlet and outlet valves arranged between the two. After the fuel was injected, a small amount of diesel fuel was ignited in the afterchamber; this ensured good swirling of the remaining fuel in the compressed air of the combustion chamber proper. Compared with the usual solution up to then – the use of a compressor to inject atomised fuel – L’Orange’s new engine with injection pump and afterchamber was appreciably more compact. But the Deutz diesel engines still were too heavy for fitting in vehicles.

After moving along to Benz & Cie. in Mannheim, with a series of innovations between 1908 and 1922 Prosper L’Orange developed the heavy oil engine further into a high-speed power unit for vehicles. The engineer’s most important improvements during this period were the prechamber principle, the funnel prechamber, the pintle-type injection nozzle, and finally the variable injection pump. However, L’Orange left Benz & Cie. in 1922 before the first diesel truck was introduced, becoming the head of stationary engine manufacture at Motoren-Werke Mannheim (MWM), which had emerged from Benz & Cie. From 1926 he worked as a free-lance engineer, and in 1927 he took over the management of the firm REF-Apparatebau GmbH in Stuttgart-Feuerbach. In 1932 REF-Apparatebau went bankrupt. In September 1933 Prosper L’Orange’s son Rudolf set up Gebrüder L’Orange Motorzubehör GmbH, today an enterprise of the Tognum Group. His father was honoured for his lifework in 1939 with an honorary doctorate from Karlsruhe Technical University. Prosper L’Orange, pioneer of the modern diesel engine, died on 30 July 1939 in Stuttgart.

1909 – The prechamber
In 1908 Prosper L’Orange was hired by Benz & Cie. as head of engine testing. In Mannheim the engineer’s aim was mainly to improve the diesel principle, as he had done at Deutz. With his afterchamber diesel he had already taken a first step towards splitting mixture formation and the combustion chamber. Now he experimented on an improvement to the shape of the cylinder head. For this work L’Orange designed a test engine that could be fitted with different cylinder heads.

On this engine he also tried out a variant in which a semispherical chamber was arranged between the injection nozzle and the cylindrical combustion chamber. In this space, which occupied 20 percent of the total cylinder volume, after injection a small portion of the diesel fuel burnt upon contact with the hot chamber wall. This created an extremely high pressure in the prechamber, driving the remaining diesel-air mixture into the cylinder and ensuring very good mixing there due to the turbulence of the compressed intake air. Pressure and mixing enabled rapid combustion at high temperatures. With the prechamber diesel, therefore, appreciably higher engine speeds were possible than with older forms of the compression-ignition engine.

In a first test run, the prechamber diesel proved robust, reliable, and above all economical. The engine continued to cause problems for its designer, not the smallest of which was that it was still too big to be installed in an automobile. But Prosper L’Orange knew he was on the right track in his work: on 14 March 1909 he submitted a patent application for the prechamber system (DRP 230 517). L’Orange was rewarded for his success by Benz & Cie. by being given the position of an authorised officer in the stationary engine construction unit in 1910.

1919 – Funnel prechamber, pintle-type injection nozzle and variable injection pump
The First World War put a stop to the further development of diesel technology at Benz & Cie. In 1915 the Mannheim people even gave up the prechamber patent entirely. So when L’Orange resumed the work on a modern diesel engine after the war’s end, he not only remembered his own groundwork, but also examined other new concepts. He happened upon the Swedish Ellwe diesel engine with semispherical prechamber and bores connecting it with the combustion chamber.

Spurred by the competitor’s development, L’Orange continued improving his own prechamber. With a funnel-shaped insert between prechamber and combustion chamber he changed its shape to achieve reliable ignition and good combustion under different loads. Among other things, the new shape improved the vaporisation of the diesel oil and reduced the risk of carbon deposits. He applied for a patent on this modification on 18 March 1919 (DRP 397 142). Parallel to this he was working on a new injection nozzle that worked much better than earlier variations. Prosper L’Orange also introduced this pintle-type injection nozzle in 1919.
In 1921 a variable injection pump for the diesel engine followed. Its delivery quantity could be infinitely varied, and it finally enabled the engineer to regulate the power output of the engine with the precision required for use in automobiles. The first installation of a high-speed diesel power unit in a vehicle was now only a matter of time.

Source: Daimler AG

1954 – Test drive through the USA
Bill Carroll undertook a test drive straight across the USA in 1954 in a Mercedes-Benz 190 D. The journey of 8243 kilometres (5122 miles) took the motor sport journalist from Seattle to New York. The diesel fuel for the ride across the continent cost the tester all of 32 dollars and 27 cents. “For Americans this fuel consumption is utterly sensational,” a German report on the journey said. And the journalist’s conclusion was an unequivocal recommendation to buy: “For anyone who has to drive long distances, the Mercedes-Benz 190 D is the best car.”