BMW will introduce a mild hybrid diesel concept vehicle—based on the BMW X5—at the 2008 Geneva Motor Show in March. The seven-passenger vehicle will utilize a 2.0-liter four-cylinder diesel engine with variable twin turbo, common rail injection—promising 36 miles to the gallon and 200 horsepower. The company calls the diesel hybrid, “BMW Vision EfficientDynamics.”

Many analysts believe that the economics of combining a diesel engine and a hybrid system—both of which add significant production costs—make diesel-hybrids a difficult proposition. “This is no pie-in-the-sky project,” said Klaus Draeger, head of development at BMW. “All of the features are production-feasible. We could easily and without too much delay apply the various technology featured on our latest concept to existing showroom models.”

The hybrid system uses a 120V lithium ion battery. Electric assist comes from a 15kW motor paired up with an 8-speed automatic transmission. The lithium ion battery pack and system can support ancillary systems such as air conditioning when the engine is switched off at idle or stop. The BMW Vision EfficientDynamics also features aerodynamic wheel rim designs and a solar roof which acts as an additional energy source.

BMW is using a “modular” approach of mixing and matching various hybrid technologies, fuel sources and engine sizes. Last fall, at the Frankfurt Auto Show, the company showed the larger and more powerful X6 sport activity coupe—a full hybrid eight-cylinder gas-electric hybrid. These vehicles are concept studies, with no announced production dates.