Detroit - The long-awaited cleaner, greener version of the Mercedes M-Class off-roader is due to go on sale this autumn, the German carmaker revealed at the Detroit car show which lasts until January 25.

The M-Class hybrid mates the familiar 3.2-litre, low-emission Blue Tec diesel engine to a 4x4 transmission incorporating twin electric motors. Mercedes says the combination will cut fuel consumption by 30 per cent compared to the standard model. Carbon dioxide emissions are set to be under 200 gm/km.

Mercedes and BMW have developed the twin-hybrid technology together with General Motors and Chrysler and the drivetrain is likely to feature in a range of other models.

Speaking at the show, developer Neil Armstrong said the hybrid M-Class would turn out around 340 horsepower. The electric motors will be used to boost acceleration and recharge a substantial on-board battery. In purely electric mode, however, the off-roader can cover only a short distance before the power runs out.

Mercedes and BMW have developed the technology together with General Motors and Chrysler. News of the upcoming M-Class hybrid first broke nearly four years ago and Mercedes-Benz has been promising its imminent arrival since the 2007 Frankfurt car show. (dpa)