Powerful power delivery, impressive pulling power, exhilarating agility – coupled with frugal fuel consumption. The AMG 6.3-litre V8 engine in the new Mercedes-Benz E 63 AMG combines these apparently contradictory qualities. All thanks to an entire package of efficiency-enhancing measures.
With peak output of 386 kW/525 hp from a displacement of 6208 cc the AMG 6.3-litre V8 engine ranks among the world’s most powerful standard-fit eight-cylinder naturally aspirated engines. The rated speed of 6800 rpm and the maximum engine speed of 7200 rpm are the hallmarks of this high-revving engine. But it also boasts enormous pulling power: developing 630 newton metres at 5200 rpm, the AMG V8 offers more torque than any other naturally aspirated engine in this displacement and performance class. High pulling power at low engine speeds, instant responsiveness and exhilarating high-revving flexibility are the strengths of the AMG 6.3-litre V8 engine unveiled in 2005.
With fuel consumption of 12.6 litres per 100 kilometres the new E 63 AMG betters its predecessor by 1.7 l/100 km or 12 percent, despite the extra output of 8 kW/11 hp. As such, the new high-performance saloon leaves the competition standing. This significant reduction in fuel consumption comes courtesy of a wealth of innovative measures: the E 63 AMG is the first AMG model to feature alternator management with braking energy recovery as standard. The controlled fuel supply, friction-optimised twin-wire-arc-sprayed (TWAS) coating on the cylinder walls and the AMG SPEEDSHIFT MCT 7-speed sports transmission with the Controlled Efficiency consumption-optimised transmission mode and wet start-up clutch, which replaces the torque converter, are crucial elements in improving efficiency.
Key data at a glance:
Recuperation: generating energy during braking
Alternator management on the new E 63 AMG takes advantage of the engine’s overrun phases and braking to recover kinetic energy. This energy is then used to charge the battery, rather than being wasted by simply generating heat. This recuperation assists the driver not only during braking action but also helps convert the braking energy into electrical energy. Conversely, the alternator is switched to no-load operation during acceleration, thus reducing the load on the engine. All of which saves fuel: some 0.15 litres per 100 kilometres as per NEDC ratings and up to 0.2 l/100 km on urban roads with frequent overrun and braking phases.
The twin-wire-arc-sprayed (TWAS) coating on the cylinder walls – used exclusively by AMG – produces outstanding low friction while reducing fuel consumption at the same time. The electronically controlled fuel supply works in the same way: depending on the power requirements and outside temperature, the system operates at a demand-actuated fuel pressure of between 3.6 and 4.5 bar and is regulated at lightning speed. The engine management system translates the command from the accelerator within milliseconds into the corresponding fuel pressure setting. Such control ensures rapid vehicle response and a sporty thrust across all load ranges and at all engine speeds.
Know-how from motor racing went into the design
In typical AMG fashion, the design of the AMG 6.3-litre V8 engine has been based closely on its motorsports counterparts. As customary with the thoroughbred racing engines, the AMG engineers opted for a closed-deck design with the crankcase made entirely out of aluminium for the eight-cylinder unit. To produce a crankcase with superb torsional stiffness, the bottom section of the crankcase has been designed as a bedplate. This produces a very stiff tunnel for the crankshaft which can easily withstand the high combustion pressures and reduces flow losses within the crankcase. The resulting improvement in mechanical efficiency helps reduce fuel consumption. An oil scavenger integrated into the bedplate reduces engine oil foaming.
The finely balanced crankshaft is designed for the highest stresses, consists of the high-quality forged steel alloy 42CRMo4V, rotates in five crankshaft bearings and features six counterweights for perfectly balanced masses. Torsional rigidity, long-term structural strength and inertia characteristics are also to the very highest standards. Two lightweight connecting rods forged by the cracking process are connected to each of the four crank pins. During this process, the utmost production precision is made possible by a predetermined breaking point created by a laser beam. Extremely close weight tolerances between the eight connecting rods are also ensured by precision machining. The same principle is also used for the cast, lightweight pistons. They are made from a durable high-temperature alloy. Pressure-controlled oil spray nozzles in the crankcase ensure optimal cooling of the highly stressed piston crowns.
Variable intake manifold with two internal throttle flaps
The aerodynamically designed intake system with large cross-sections and the variable intake manifold made of magnesium with two integrated throttle flaps ensure superlative cylinder charging. Its task is to ensure a strong torque curve by lengthening the airflow distance at low engine speeds. At higher engine speeds the intake manifold switches to short airflow distances to achieve a high peak performance. The two throttle flaps can be opened to their maximum in just 100 milliseconds at full throttle, and the driver perceives this as extraordinary responsiveness.
Rigid valve train, four overhead camshafts
The 32 valves in the cylinder heads are operated by bucket tappets. Their space-saving design allows a stiff valve train and therefore high engine speeds with large valve opening cross-sections, which in turn benefits output and torque. The large intake valves have a diameter of 40 millimetres, while their opposite numbers on the exhaust side measure 34 millimetres.
All four overhead camshafts are continuously variable over a range of 42 degrees. Both the intake and exhaust camshafts are adjusted as a function of engine load and engine speed, ensuring extremely high output and torque values and smooth idling, and especially low exhaust emissions. Depending on the engine speed, the valve overlap can be varied to ensure an optimal supply of fuel/air mixture to the combustion chambers and efficient venting of the exhaust gases. The system is driven by a duplex roller chain and intermeshing pairs of gear wheels.
Sophisticated engine cooling solution
A powerful oil pump is used for the oil cooling system on the engine. As in thoroughbred racing engines, the engine is cooled on the sophisticated cross-flow principle. In the interests of optimal in-engine friction and fuel economy, the temperature of the coolant is also variably controlled. The lightweight, compact and powerful cooling module – located behind the large apertures in the AMG front apron – for coolant, engine, transmission and power-steering oil ensures non-critical operating temperatures – even under the extreme stress of the racetrack. The hot air from the suction-type fan used for engine oil cooling is vented via the side apertures in the AMG front apron.
Distinctive AMG V8 vocals, efficient emission control system
The newly composed AMG V8 vocals fully live up to the expectations of a powerful high-performance saloon: a powerful engine sound when accelerating coupled with restrained running characteristics during smooth cruising, providing hallmark Mercedes long-distance comfort. The AMG experts have resolved this conflict of aims with a newly developed AMG sports exhaust system; it comes with carefully matched tube cross-sections and two newly designed chrome-plated twin tailpipes.
Thanks to efficient emission control technology, the E 63 AMGmeets current EU 5 exhaust emission standards and all requirements of the U.S. market (LEV-II standard, On-Board Diagnosis II and oxygen sensor diagnosis).
Engine production – tradition of hand-built excellence
The AMG 6.3-litre V8 engine has traditionally been built by hand. In the AMG engine workshops, which were opened in 2002, a highly qualified engineer assembles an eight-cylinder engine according to the company’s philosophy of “one man, one engine” in compliance with the most stringent quality standards. The engineer’s signature on the characteristic AMG engine plate is testimony to the highest standards of workmanship. Production takes around three hours.
In the coveted “International Engine of the Year Awards 2009”, the AMG 6.3-litre V8 engine carried off two awards: in the “Best Performance Engine” and “Above 4 litres” categories, this high-revving, naturally aspirated engine took first place by a wide margin in each case.
Source: Daimler AG
Quelle: Daimler AG