BMW's Vision EfficientDynamics concept bound for Frankfurt

BMW has revealed a radical vision for its future performance-oriented models in a spectacularly styled concept car whose combination of M3-rivaling acceleration and Mini Cooper-beating fuel economy will likely make it one of the stars of this year's Frankfurt motor show.

Called Vision EfficientDynamics, the one-off coupe is a mobile showcase for lightweight construction and plug-in hybrid drive technology, while featuring a variety of futuristic styling, packaging, aerodynamic, lighting and interior ideas under development at the German carmaker's heavily cloaked FIZ development center in Munich. Many of the concepts are planned for use on upcoming BMW road cars, including an exciting Z10 EfficientDynamics range-topping model due by 2015.

At the heart of the concept car is an advanced diesel-electric hybrid system, based on a compact turbocharged 1.5-liter, three-cylinder common-rail diesel engine that will first appear in the second-generation 1-series due in 2011.

The front-mounted engine features a gutsy 163 hp and 214 lb-ft of torque, making it more powerful than the latest and most-economical version of BMW's existing turbocharged 2.0-liter four-cylinder. It channels drive to the rear wheels via a version of the Getrag-developed six-speed dual-clutch gearbox introduced on the M3.

The diesel engine is supported by a pair of electric motors mounted at the front of the gearbox, one supplying drive to the rear wheels, the other to the front wheels via a single-speed transmission.

The electric motor for the rear wheels produces 25 kilowatts and 214 lb-ft of torque, but is capable of up to 38 kilowatts for short bursts. The motor driving the front wheels delivers 60 kilowatts and 162 lb-ft of torque, but can supply up to 104 kilowatts momentarily. Altogether, the combined diesel-electric powertrain is good for 356 hp and 590 lb-ft of torque.

This endows the 3,069-lb concept with a power-to-weight ratio close to that of 4.0-liter, 420-hp V8-powered M3, and with a comparable 4.8-second 0-to-62-mph time, according to BMW. At the same time, BMW says its hybrid concept should be good for a combined fuel-economy rating of 90.2 mpg.

Electricity comes from plugging into to the grid, or from regenerative braking and coasting. Recharging is estimated at 2.5 hours at 220 volts, or just 44 minutes at 380 volts. The 187-lb lithium-polymer battery pack produces up to 364 volts and has a storage capacity of 10.8 kilowatt-hours.

The interior of BMW's Vision EfficientDynamics concept includes an iDrive controller.

Depending on the driving conditions, the Vision EfficientDynamics is engineered to run exclusively on its electric motors, the diesel engine or a combination of diesel and electric motors. Maximum range in pure electric mode is estimated at 31 miles, with the diesel engine offering an additional 400 miles.

Together with improved versions of BMW's brake-energy regeneration, auto stop/start and active air control, the Vision EfficientDyanmics also adds a feature to its arsenal to help bolster energy efficiency in the form of what BMW describes as a thermo-electric generator integrated into the exhaust system. Originally developed for use in spacecraft, it converts thermal energy into electrical energy by way of a semiconductor, which is then used to power features such as the steering, air conditioning and seat-adjustment motors.

As well as highlighting technical developments expected in BMW production cars within the next five years, the Vision EfficientDynamics also acts as a template for BMW's future design lineage. The first car to be styled completely under BMW Group design boss Adrian von Hooydonk adopts a radical shape that features ideas that should begin appearing on all BMW models in the near future.

Von Hooydonk's team has attempted to instill visual lightness within the body of BMW's latest concept through the extensive use of glass covering most of the hood, roof, sides and trunk lid. The team also has taken liberties with traditional BMW elements, such as the concept's interpretation of the kidney grille.

Inside, the Vision EfficientDynamics offers 2+2 seating, accessed via butterfly-style doors that extend along the complete side of the car. A prominent center tunnel divides the plush leather-lined interior, which features a futuristic-looking dashboard and associated trim panels mirroring the layered surfacing of the exterior.

Since the appearance of the X Coupe concept car at the Detroit auto show in 2001, the design of BMW's road cars has been heavily dictated by what its former design boss, Chris Bangle, liked to describe as flame surfacing--a combination of convex and concave forms within the body surfacing conceived to lighten the visual effect of the sheet metal.

With the unveiling of the Vision EfficientDynamics at this year's Frankfurt motor show, new design boss Adrian von Hooydonk is heralding a new direction in BMW design, described as "layered surfacing." The new look doesn't consign flame surfacing to the dustbin, but instead strives to enhance its effect even further. It involves layering one surface on top of another to improve aerodynamic efficiency and to achieve a more cohesive and harmonious appearance.

For example, the shape of the A-pillars channel the flow of air in the same way as the rear lights with their wing profile, according to von Hooydonk. The concept also boasts very few cooling ducts and a full length undertray, all of which results in a low 0.22 coefficient of drag.

"By using the structure of the surface without adding any appendages, we're able to optimize the air flow," says von Hooydonk, who rose to prominence following the unveiling of the Z9 Grand Turismo concept at the 1999 Frankfurt motor show, a car which previewed the look of today's 6-series.

By Greg Kable