BMW has released its new 2008 BMW 6 Series Coupé and BMW 6 Series Convertible. The BMW 650i contains a 4.8 liter eight-cylinder engine, while the BMW 635d is powered by a 3.0 litre straight-six diesel engine. The new models also feature new technologies designed to increase fuel-efficiency and safety. To achieve maximum fuel-efficiency, BMW officials report the belt drive for the air conditioner compressor now comes with its own clutch. By creating a separate clutch, the vehicle will automatically disconnect from the compressor as soon as the driver switches off the air conditioning. Both vehicles also contain a Lane Departure Warning system, a program that alerts drivers (who may have fallen asleep at the wheel) that they are about to switch lanes.