A new naturally aspirated 5.5litre V8 engine from Mercedes-AMG will boast a cylinder management cylinder shut-off system that helps it to reduce fuel consumption by 30 per cent.
The fuel economy breakthrough has been achieved even though the peak output in the new engine has increased by 60hp to 415hp and torque leaps from 376lb-ft to 398lb-ft. The engine will be applied exclusively in the 2012 SLK55 AMG, which will debut at the International Motor Show inFrankfurtin September.
Known as the M152 engine, it is based on the AMG M157 5.5litre V8 bi-turbo engine which originally debuted in the 2011 CL62 AMG and the S63 AMG. Its components are basically the same but distinctive features include new intake air ducting, new cylinder heads, a modified valve drive, an adapted oil system and an optimised crankcase.
With the cylinder shut-off system, cylinders two, three, five and eight are cut off under partial load. The technology is already being used in the 750hp V8 engines in Formula 1 where two or four of the eight cylinders are cut off when cornering at low speeds.
The shut-off system will be available over a wide engine speed range from 800-3,600rpm and is enabled by an engine management system with 16 hydraulic actuators and a complex oil supply system in the cylinder head.
In addition, the engine benefits from several other efficiency driven features including an all aluminium crankcase with silitec cylinder liners; weight optimised cast aluminium pistons with special piston skirt coating; ventilation holes in the crankcase; separate oil pump for cylinder shut-off; an oil pump with electronically controlled pressure stage; engine cooling on cross-flow principle; and electronically controlled fuel pressure. A controlled efficiency stop/start function is included as standard and further contributes to the low fuel consumption.
