Substantially more agile and efficient, but as comfortable and spacious as ever – the new B-Class from Mercedes-Benz is a winner on all fronts. The vehicle’s lower height and more upright seat position provide for a first impression that hints at the compact sports tourer’s dynamic credentials.
With a new four-cylinder petrol engine featuring direct injection and turbocharging, a new diesel engine, a new dual clutch transmission, a new manual transmission and new assistance systems, the front-wheel drive car also rings in a new technological era for compact cars from Mercedes-Benz. “No model change in the history of Mercedes-Benz has ever seen so many new developments introduced in one fell swoop,” stresses Dr. Thomas Weber, Member of the Board of Management responsible for Group Research and Head of Development, Mercedes-Benz Cars. “Future B-Class customers will benefit from this quantum leap in terms
of exemplary low fuel consumption and CO2 emissions combined with driving pleasure, plenty of space and the customary high standard of safety from Mercedes-Benz.”
The world premiere of the new B-Class (length/width/height: 4359/1786/ 1557 millimetres) will take place at the Frankfurt International Motor Show (13 to 25 September 2011). It will be making its way to European dealers in November 2011.
Outstanding aerodynamics: astounding cd value despite station wagon rear end
An outstanding drag coefficient of cd = 0.26 places the new B-Class at the forefront of its market segment. Apart from the aerodynamic exterior design, numerous optimisation measures on points of detail such as the air flow around the front wheels, the underbody design and the cooling air flow are also crucial contributory factors to this excellent aerodynamic performance. Patents are pending for innovative details such as the serrated wheel arch spoiler. With the optional ECO Technology package, which will be available at a later date, the B-Class even achieves the world-class aerodynamic credentials of the E-Class Coupé, attaining a drag coefficient of cd = 0.24 which is nothing short of sensational for a vehicle with a station wagon rear end.
New engines, new transmissions: designed for maximum efficiency
The new B-Class features new petrol and diesel engines as well as new manual and automatic transmissions. All transmissions and engines have been developed in-house, with production taking place at the plants in Stuttgart-Untertürkheim and -Hedelfingen, Rastatt/Baden, Gaggenau/Baden and Kölleda/Thuringia. The simultaneous development process enabled perfect coordination of engines and transmissions, e.g. with regard to implementation of the ECO start/stop function which features as standard on all B-Class models.
Common features of the new drive systems are the use of state-of-the-art technologies for maximum efficiency, very smooth running, high tractive power right from low revs, sustainability in terms of compliance with forthcoming emissions standards and low weight. For the purposes of transverse installation the engines, all of which are turbocharged, and the two transmissions are very compactly designed, providing the
B-Class with an exemplary small turning circle for a front-wheel drive vehicle of under eleven metres. The engine and transmission suspension disposes of a four-point mounting system comprising engine mount, transmission mount and two self-aligning supports. This suspension system has been designed specifically to meet the requirements of the high-torque engines with regard to minimum noise levels. The hydraulic damping integrated in the transmission mount is a key contributory factor to the exceptionally high ride comfort.
The new four-cylinder petrol engines (internal designation M270) mark the launch of a completely new engine series. The combustion process is based on the third-generation Mercedes-Benz direct injection system which was introduced last year with the BlueDIRECT V6 and V8 engines. Its use in the B-Class marks this technology’s debut in the compact segment. The new four-cylinder engines have been designed for both transverse and longitudinal installation. In the new B-Class they are initially available with a displacement of 1.6 litres, as the B 180 rated at 90 kW (122 hp) and the B 200 with an output of 115 kW (156 hp). Their maximum torque of 200 and 250 Nm respectively is available from an engine speed of 1250 rpm.
The new four-cylinder diesel engine is a further development of the OM651 deployed in the C- to the S-Class, a common rail direct-injection engine of the third generation. With its displacement scaled down to 1.8 litres and numerous optimised points of detail, this is the first time that the compression-ignition engine has been mounted transversely in a Mercedes-Benz car. The B 180 CDI generates 80 kW (109 hp) of power, while the B 200 CDI has an output of 100 kW (136 hp). The maximum torque stands at 250 Nm from 1400 rpm for the 80 kW variant and 300 Nm from 1600 rpm for the 100 kW variant.
Another Mercedes-Benz premiere is the new 7G-DCT dual clutch transmission in the B-Class. This transmission is extremely compact, extremely variable with regard to adaptation of the engine speed thanks to seven gears, incorporates an electric oil pump for start/stop capability, shifts gear without any interruptions in tractive power and combines the comfort of an automatic with the efficiency of a manual transmission.
The new 6-speed manual transmission designed along similarly compact lines as a three-shaft transmission is a close relative of the DCT. Extremely easy gear shifting, low shift forces, low internal friction and a low weight are among its most important characteristics.
Chassis and suspension: refined sportiness now for the sports tourer, too
“Fascinatingly agile” is the assessment of all test drivers who have put the new B-Class through its paces to date. Three factors are instrumental to the substantially enhanced dynamic performance in comparison to its predecessor, which does not come at the cost of any compromises on comfort: the lowered centre of gravity, the new four-link rear axle and the upgraded ESP Electronic Stability Programme. A sports suspension is optionally available for further enhanced agility. This suspension is lowered by 20 mm for an even lower centre of gravity and features sports dampers with amplitude-selective damping and a Direct-Steer system to emphasise the car’s sporty character.
Steering: mechanical with electric assistance
The electromechanical steering of the B-Class has been redesigned. The electric motor of the servo assistance system is now located directly on the steering gear as a dual pinion EPS system, thereby optimising the package as a whole. A Direct-Steer system is available in combination with the sports package. Locating the EPS system here results in a noticeably more direct steering ratio over the turning angle with the aid of the variable ratio. This enhances the vehicle’s handling and agility substantially.
The electromechanical steering system makes an important contribution to the vehicle’s overall efficiency, as the steering assist function only requires energy when steering actually takes place.
New assistance and braking system reduces the risk of rear-end collisions
As a world first in the compact segment, the B-Class features a radar-based collision warning system with adaptive Brake Assist as standard, which lowers the risk of rear-end collisions. The COLLISION PREVENTION ASSIST system gives a visual and acoustic warning to alert a possibly distracted driver to identified obstacles, and prepares Brake Assist for the most precise possible braking response. This is initiated as soon as the driver emphatically operates the brake pedal.
In contrast to other systems available on the market for the compact class, the new COLLISION PREVENTION ASSIST feature is not merely an urban driving system designed to minimise the effects of minor collisions. Rather, this innovative solution aims to provide protection against typical rear-end collisions in all dangerous driving situations at speeds of over 30 km/h. Mercedes-Benz expects the new safety system to have a significant, positive effect on accident statistics.
The democratisation of safety also encompasses an array of other assistance systems which have been adopted into the B-Class from the larger model series. These include:
- Adaptive Headlamp Assist
- Blind Spot Assist and Lane Keeping Assist
- ATTENTION ASSIST (standard)
- Speed Limit Assist (speed limit sign recognition)
- Active Parking Assist
- Brake HOLD function (standard with 7G-DCT)
- Hill Hold function
- Reversing camera
- DISTRONIC PLUS with BAS
- PRE-SAFE (featuring for the first time in this class of vehicle).
Driving simulator: performance capabilities unsurpassed in the car industry
Fine-tuning of the safety systems prior to deployment in real test-drive conditions took place in the new driving simulator at the company’s Technology Centre in Sindelfingen. With its 360° screen, fast electric power system and the twelve metre-long rail for transverse or longitudinal movements, the dynamic driving simulator is the most powerful in the entire car industry. It went into operation at the end of 2010.
A dome measuring 7.5 metres in diameter is mounted on six individually extendable cylinders forming a so-called hexapod and on a linear motion system. A complete vehicle is installed in the dome. The inner surface of the dome serves as a projection panel on which road traffic situations are displayed true-to-life, with moving pedestrians, oncoming traffic and housing. The handling of any current or future Mercedes model can be simulated mathematically and the test driver experiences the calculated vehicle movements realistically and in real time by means of the motion system.
Plenty of space inside, prepared for alternative drives
The new vehicle concept underscores the dynamic aspirations of the new B-Class. The most striking aspect is the reduced height: at 1557 millimetres, the new model crouches almost five centimetres lower on the road than its predecessor. The seat height in relation to the road has also been reduced (minus 86 mm). In response to requests from many customers, the seat position is more upright, however. The headroom has nevertheless been further improved. With 1013 mm of headroom at the front (without sliding roof), the B-Class is among the most spacious cars in its segment in this discipline, too.
The B-Class is optionally available with the so-called EASY-VARIO-PLUS system. This enables simple reorganisation of the interior so as to enable the transportation of bulky items. Features of the EASY-VARIO-PLUS system include fore/aft adjustment of the rear seats by up to 140 millimetres and a front passenger seat whose backrest can be folded forward onto the seat cushion.
The new B-Class features an enhanced variant of the sandwich floor. The modular “Energy Space” concept means that it is already designed to accommodate versions with an alternative drive: appropriate interfaces in the body shell enable the main floor panel to be modified and a step to be produced for the versions with alternative drive. This multifunction well begins under the driver’s seat and offers space for the alternative energy accumulators.
Source: Daimler AG / Pictures: MB Passion + Daimler AG