BMW's Diesel Plug-In Hybrid: 63 mpg, Faster Than an M3

BMW_Vision_Hero_7421.jpg
BMW’s EfficientDynamics Vision concept car combines the best of all worlds with incredible fuel efficiency, breaktaking performance, and sensational looks. It’s powered by a three-cylinder turbo-diesel engine, lithium polymer batteries, and electric motors front and rear. The BMW Vision gets a U.S. unveiling next week at the Los Angeles Auto Show, Dec. 4-13. The only bad news: The BMW Vision is more vision than production-ready concept car. What you’d most likely see on sale would be the key components such as the drivetrain and battery technology transplanted to a more mainstream body.

 

On a stopover from Europe en route to L.A., BMW held a series of press briefings at its Chestnut Ridge, N.J., U.S. headquarters. According to BMW, the goal was to create a car that would be as quick as BMW’s V8 M3, yet tread lightly in terms of environmental impact. Here’s how the BMW Vision has the potential to win the hearts and minds of hot-rodders, environmentalists, and techies alike:

Total output from the engine and electric motors is 356hp, and peak torque is 590 foot-pounds (a lot). Acceleration to 100 kph (62 mph) takes just 4.8 seconds and speed tops out at 155 mph. Average fuel consumption is 62.6 mpg or 3.76 liters/100 km in European figures. The fuel economy translates to CO2 emissions of 99 grams per kilometer; getting below 100 is the holy grail by EU standards.

The Vision has a range of 431 miles, BMW says: 31 miles in all-electric mode, about the same as the Chevrolet Volt, plus 400 miles from the 6.6 gallon fuel tank. BMW hasn’t yet tried to play the U.S.-automaker mpg numbers game, saying that since most trips are less than 30 miles, and since big powerplant generation is more efficient than using a combustion engine, the effective mileage is up around 200 mpg. What is clear is that electric motors are extremely efficient, as are big power plants, so the effective cost of energy is less than half that of diesel or gasoline fuel.

The three-cylinder, 1.5-liter engine alone produces 163 hp. BMW says the output of 109 hp per liter is the most power produced by a diesel engine. It’s small enough to fit ahead of the rear axle for better weigh distribution. Power travels to the rear wheels via a six-speed double-clutch transmission.

One electric motor, in back, sits between the diesel engine and transmission and produces 33 hp (51 hp peak). It can run on its own, without the combustion engine, making the Vision what’s considered an active hybrid, as opposed to a mild hybrid where the combustion engine always powers the car. The second motor powers the front axle; it produces 80 hp (continuous), 112 hp (30-second bursts), or 139 hp (10-second bursts). The two motors also act as brakes and regenerate power into the lithium polymer battery pack that runs in a tunnel along the floor of the car. Fuel for the diesel engine is in the rear of the tunnel (separate compartment; it doesn’t just slosh around the batteries).

The battery pack has enough juice to bring anyone back from cardiac arrest (or cause it): 98 lithium-polymer cells deliver 30 amp/hours at 3.7 volts, or 111 watt-hours. So each cell is about equal to two laptop batteries. For periods of up to 30 seconds, each cell develops 1,200 amps. Plug the Vision into a standard (in Europe) 220-volt, 16-amp circuit, and the car fully recharges in 2.5 hours. Uses 380 volts and 32 amps and you’re back on the road in 44 minutes. Conversely, you’d be looking at overnight plugged into 120 volt U.S. power.

Since it’s a concept car, cost and practicality aren’t the main concerns. BMW has provided some stunning visual touches:

Windshield and Roof From One Piece of Glass
BMW_Vision_Glass_P90047123_highRes.jpg

The windshield and roof are a single piece of glass (or polycarbonate). The body is carbon fiber and the chassis is aluminum, all of which yields a weight under 3,000 pounds, a third of a ton less than the BMW M3.

Glass Cockpit
BMW_Vision_HUD_P90047173.jpg

The instrument panel consists of both a small display in front of the steering and a big head-up display.

iDrive in the Center Console
BMW_Vision_iDrive_P90047161.jpg

Since it's a BMW, there's iDrive. Of course.  

Alloy Wheels Help Channel Airflow
BMW_Vision_Wheel_MG_7422.jpg

The alloy wheels look like a child’s pinwheel, less so to extract heat from the brakes (regeneration means the brakes don’t work that hard on this car) but to help move air in a continuous boundary layer over the bodywork. There’s also a small slit in the front fender that channels air around the wheels. BMW says the tires are a new generation that provides low rolling resistance without giving up handling.

Airflow Over the Body
BMW_Vision_Airflow_P90050695.jpg

The trademark BMW kidney grille opens and closes to channel airflow at different speeds for reduced wind resistance.

Thin Seats Save Space
BMW_Vision_Seats_P90047164.jpg

The seats are meant to be supportive but almost wafer thin. Don’t carry whiny 5-year-olds in back if they’re prone to show displeasure by kicking the front seatbacks. Not that you’d want kids in a car with white and light-color upholstery anyhow.

 

Leave a Reply

Your email address will not be published. Required fields are marked *