BMW has already announced two hybrid vehicles that will debut at the 2009 Frankfurt auto show, so the fact that its latest concept is also a hybrid shouldn't be terribly surprising. However, we didn't expect the Vision EfficientDynamics concept to be a turbo-diesel hybrid that uses a lithium-polymer battery pack and be capable of a 0-62 mph sprint in a mere 4.8 seconds. If the M division ever decided to build a hybrid the results couldn't be too different from what we see here.
The soul of the Vision EfficientDynamics concept is its 1.5-liter three-cylinder turbo-diesel engine and plug-in hybrid components. Using the diesel engine alone, the car has 163 hp and 214 lb-ft of torque thanks to technologies such as high-pressure direct injection and variable intake geometry. BMW managed to squeeze the little diesel engine ahead of the rear axle, but behind the rear seats for better handling characteristics and aerodynamic considerations. Power is sent from the engine to the rear axle through a six-speed dual-clutch automatic transmission, or "DCT" in BMW-speak. An electric motor is sandwiched between the engine and transmission and is capable of adding 51 hp and 214 lb-ft of torque to the total output. The electric motor can be used to power the vehicle without any help from the diesel engine when the battery has enough charge. Naturally the motor makes regenerative braking possible and feeds power back into the lithium-polymer battery pack during coasting and braking situations. Another electric motor can power the front axle and is rated at 80 hp and 162 lb-ft of torque for continuous operation. For 30 seconds, the output can be increased to 112 hp and 139 hp is available for a 10 second burst. A single-speed transmission sends this power to the front wheels and enables all-wheel drive.
BMW claims the Vision EfficientDynamics concept can run on power from the diesel engine alone, the electric motors alone, or with any combination of those sources. When maximum thrust is called for, like in passing situations, the combined output of the engine and two motors is 356 hp and 590 lb-ft of torque. Quite impressive when you remember this is only a three-cylinder engine displacing 1.5-liters. Perhaps the replacement for displacement is technology, electric motors and a 3076 pound curb weight. ...next page >>