BMW Vision EfficientDynamics diesel hybrid concept

The BMW Vision concept car is the latest in a string of “EfficientDynamics” ideas by the German automaker. Conceived as a 2+2-seater with plug-in full-hybrid technology, this concept car combines the performance of a BMW M vehicle with a standard of fuel efficiency and emission management that exceeds even the current levels achieved by the latest small cars. This result is made possible by the combination of BMW ActiveHybrid components with an economical combustion engine and good aerodynamic qualities.

The powertrain provides a top speed limited electronically to 250 kph, with acceleration to 100 kph in 4.8 seconds. Average fuel consumption in the EU test cycle is 3.76 litres/100 km and the CO2 emission rating is 99 grams per km.

This is made possible by combining a mid-mounted 1.5-litre 3-cylinder turbodiesel with one electric motor on each axle. Engine output is 163 hp with peak torque of 290 Nm. With precisely-controlled energy management, the overall system output is 356 hp, and peak torque is 799 Nm. The special arrangement of the two motors and diesel engine allows all-wheel drive when driving in all-electric mode. BMW Vision EfficientDynamics features a newly-developed version of BMW’s DCT gearbox with six speeds for maximum efficiency and flexibility.

The energy cells featured in BMW Vision EfficientDynamics are housed in the middle of the car. The front unit is the lithium-polymer complex, an ongoing development of the lithium-ion battery. Overall, BMW Vision EfficientDynamics comes with a total of 98 lithium-polymer cells, each offering a capacity of 30 amp/hours and developing continuous output of 600 Amps at a voltage of 3.7 V. For a period of 30 seconds, each cell is even able to develop maximum output of 1,200 Amps.

The serial arrangement of the lithium-polymer cells serves to generate nominal voltage of 364 volts, and the gross storage capacity of the battery is 10.8 kW/h. With an unusually high discharge capacity of 80 percent, the battery delivers 8.6 kW/h for driving the car. This superior performance comes with an overall weight of the entire energy storage system of just 187 lb.

Brake Energy Regeneration captures electric power generated while driving without additional fuel consumption, which is subsequently used to supply power to the electric motors and onboard network. A further option is to connect the lithium-polymer cells to a conventional power socket for a simple and efficient charge process, using a plug-in connector in the front-right wing of the car. Connected to a standard 220V power outlet, the system requires a maximum of 2 ½ hours to fully charge the lithium-polymer cells. And wherever a power source with a higher 380V voltage is available, the charge time is an even shorter 44 minutes.

The BMW Vision concept will make its debut at the 2009 Frankfurt Motor Show and hints at the future direction of BMW models.