M35 has a second clutch that disconnects the engine from the transmission to improve efficiency
3 March 2010

Infiniti launched its first hybrid at Geneva with the new M35 Hybrid, a petrol-electric version of the firm's new 5-series rival, the M saloon.

The car is fitted with Infiniti's Direct Response Hybrid system, a 3.5-litre V6 with a 67bhp/199lb ft electric motor sandwiched between the engine and the seven-speed transmission.

See the Infiniti M35 hybrid show pics

Like the Porsche Cayenne and VW Touareg, the M35 has a second clutch that disconnects the engine from the transmission to allow the car to effectively coast, reducing drag and improving efficiency.

The transmission is an upgraded version of the standard Infiniti seven-speed auto. The torque converter has been removed, which Infiniti claims makes the engine more responsive and efficient.

The engine is the US-spec V6 - European and UK Infinitis have a 3.7-litre unit - with 316bhp and 266lb ft. Infiniti chose to stick with the older V6 because development work on the hybrid started before the newer 3.7-litre engine was conceived. It weighs around 150kg more than a standard M, although Infiniti says using a laminated lithium ion battery helps to save 30kg. A laminated battery is also easier to cool than a conventional unit, which increases efficiency and longevity; the batteries should last for 136,000 miles before being replaced.

Other weight savings come from doing away with the starter motor; the electric motor turns the engine over instead. According to Infiniti sources, this presented a particular technical issue as both clutches needed to slip to allow the engine to start.

The hybrid will go on sale in around a year's time, and should make up 33 per cent of total European M sales. Total M sales in Europe are predicted to be 3500 cars in its first full year, which will be 2011.

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