Submitted 8/29/2009

BMW’s Vision EfficientDynamics concept is sure to be a hit at next month’s Frankfurt Motor Show. Not because of its scissor-like doors, outrageous design, or rapid acceleration, but because of its innovative driveline which achieves high mpg ratings without compromising performance. The Vision concept takes from the best of all worlds, melding the performance of an M3, the looks of a Lamborghini, and the fuel consumption of a Prius.

BMW’s new concept car uses a tiny 1.5 liter turbodiesel, half of the 3.0 liter diesel found in the 335d, and adds to it two electric motors. The rear-mounted three cylinder diesel puts out an impressive 163 hp and 215 lb-ft of torque, setting a new standard for diesel output with 109 hp per liter, impressive considering diesel engines are known for torque, not horsepower. Being a sports car and not a conventional hybrid, there is no boring CVT transmission watering down the experience. Instead, BMW has mated the engine to the same six-speed DCT auto-clutch transmission as used in the M3 and Z4.

The first of two electric motors sits between the diesel engine and the transmission and puts out a consistent 33 hp and 214 lb-ft of torque. During hard acceleration, the motor can peak at 51 hp. When coasting or applying the brakes, the rear-mounted motor works as an electric generator to recharge the battery pack. A second electric motor is placed up front on the axle. This motor is tuned to push out more horsepower as opposed to the rear motor tuned for low end torque. The front motor offers a continuous 80 hp with a peak torque output of 162 lb-ft. The motor is also able to pump out an increased 112 horsepower for up to 30 seconds or 139 horsepower for a 10 second acceleration burst. Power from the front motor is routed through a 2-stage single-speed reduction gearbox. Total output for the system is 356 hp and a whopping 590 lb-ft of torque. Even with all this power, the Vision can run up to 31 miles using only electrical power, and an additional 400 miles with the diesel engine, combining for a range of 431 total miles.

Powering the electric motors is a lithium-ion battery pack containing 98 lithium-polymer cells. Unlike the Chevy Volt, which can only use about 50% of the battery pack’s capacity, the BMW is able to use 80%. This higher efficiency allows for a smaller battery pack, keeping the BMW’s pack to only 187 pounds. Since the Vision is a plug-in hybrid, the batteries can be charged either by the engine and regenerative braking, or by plugging it into a wall outlet. The pack can be fully charged in just 2.5 hours using a standard 220 V European outlet.

The combination of the turbodiesel and the two electric motors propels the Vision concept to 100km/h (62 mph) in a surprising 4.8 seconds, topping out at an electronically limited 155 mph. Unlike other sports cars of this caliber, the Vision returns about 63 mpg on the EU combined cycle. C02 emission is rated at 99 grams per kilometer under normal driving and 50 grams per kilometer when running solely on electrical power. This compares favorably to the M3’s CO2 emission output of 293 g/km.

BMW didn’t stop at the powertrain, and used the concept to showcase many of its other innovative technologies. The concept uses an all-aluminum chassis and suspension along with a light-sensitive polycarbonate roof and skin. These materials keep the Vision to only 3,076 pounds. The Vision also uses polycarbonate glass which darkens when hit by light, reducing heat build-up inside the cabin. Finally, the Vision networks all of its electronic systems in a forward looking energy management system to reduce power consumption by anticipating future driving changes. An example of this would be to use the adaptive cruise control system to anticipate slower speeds due to upcoming traffic, turning on the regenerative braking ahead of time, thus using predictive technology to reduce power consumption.

You may also have noticed a lack of flame surfacing on the Vision concept. Chris Bangle, who ushered in flame surfacing on all BMWs, has been replaced by new design director Adrian von Hooydonk. Expect von Hooydonk’s design elements from the Vision to make their way into the next generation of 3 and 5 Series Bimmers. BMW also claims that many of the concept’s fuel-mising technologies will eventually make it into future production BMWs as they continue to lower fleet-wide consumption to meet stricter US and European mileage regulations. The advanced diesel technology will be the first to reach consumers, as seen in the 320d EfficientDynamics Edition sedan, debuting as a 2010 model in Europe.

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