BMW X5 HYBRID FOR CARS

The Vision EfficientDynamics employs a 2.0-liter clean diesel engine with twin variable-geometry turbochargers and direct injection that produces 204 horsepower and 295 pound-feet of torque. To fully exploit the diesel engine's relatively narrow rev range, BMW fitted the concept with a new eight-speed automatic gearbox from ZF. Flange-mounted to the transmission is an electric motor-generator powered by a lithium-ion battery pack that spins out an additional 20 horsepower and 155 pound-feet of torque during acceleration.

]The bottom line is about 36 mpg combined city/highway with emissions of only 172 grams of carbon dioxide per kilometer. Sixty miles per hour arrives in a decent 8.9 seconds (1.1 seconds slower than the X5 3.0si).

We're particularly fond of the battery-boosting photovoltaic panels in the moonroof, which also power pre-heaters for the transmission fluid and diesel fuel, supposedly cutting warmup times considerably and, in turn, further boosting efficiency. Clever, too, are 19-inch wheels with sail-shaped spokes designed for efficient ventilation and lower wind resistance. BMW claims these wheels are so finely sculpted, the engine is required to produce one less horsepower (yes, one) to maintain 100 mph than vehicle with "conventional" wheels.