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GOODBYE ENGINE, hello "skateboard": the AUTOnomy fuel cell concept car embeds all the "running gear" in the chassis.
GENERAL MOTORS

It had to have four wheels, but pretty much everything else was open for consideration. When General Motors decided to develop an all-new fuel-cell vehicle with electronic (rather than mechanical), drive-by-wire controls, our team started with a clean sheet.

Because we did not seek to shoehorn these new technologies into existing vehicle architectures, we avoided design trade-offs that had to be made in the past. We also opened up new opportunities to improve ride and handling, interior spaciousness and flexibility and exterior styling. The early result was our first concept vehicle, AUTOnomy. The working demonstration model, named Hy-wire, is being introduced officially to the world on September 26, 2002, during the Paris Auto Show.

Fuel cells cleave hydrogen atoms into protons and electrons that drive electric motors. Instead of polluting hydrocarbon emissions, fuel cell vehicles emit only water vapor from the tailpipe. Their widespread adoption could make personal transportation--a freedom already cherished by many cultures and sought with growing frequency by emerging markets--environmentally sustainable for the foreseeable future. (For more about the potential of fuel cells in automobiles, see "Vehicle of Change," by Lawrence D. Burns, J. Byron McCormick and Christopher Borroni-Bird; Scientific American, October 2002.)

Chock-full Chassis

Starting from the ground up, we placed all the "running gear"--the fuel-cell stack, drive-by-wire electronics controls and electric motors--inside the chassis. It is nicknamed for what it resembles: a skateboard. This design lowers the center of gravity compared with a conventional internal-combustion-engine-driven vehicle of similar proportions, which improves ride, handling and stability. Future advances in communication among the various by-wire systems (more on those momentarily) could supplement these advantages further, providing superior chassis performance than is possible today.

Hy-wire is a front-wheel-drive vehicle. But the AUTOnomy program goal is to place an electric motor at each of the four wheels, to improve acceleration and maneuverability. The wheel motors might allow a vehicle to almost literally turn on a dime, making parking much easier. Since wheel motors make each wheel independently variable, vehicle stability also could be improved beyond what is possible today.

The combination of wheel motors and drive-by-wire might enable the vehicle's corners to become interchangeable electronic modules, with packaging and software-tuning flexibility adaptable to multiple vehicle types. In addition, by-wire technology may make it feasible to provide remote-control operation, which could facilitate parallel parking or even let an owner back the car out of the garage in the morning when getting ready to leave for work.

Sleek, Switchable Exteriors

Beyond the functionality advances, the coupling of fuel cells with by-wire technology provides new design flexibility. There is no need to work around the awkward center cabin hump from the internal-combustion engine's driveshaft, or its conventional steering column. Planar fuel cells provide a flat foundation that offers more of a clean sheet for exterior styling--a wider variety of shapes above the plane of the skateboard chassis is possible. Moreover, eliminating the engine compartment lifts architectural constraints, enabling designers to create new vehicle profiles to tempt customers.

On the manufacturing side, by-wire technology allows automakers to reinvent the standard business model, to one centering around the use of interchangeable bodies on top of a common chassis. A limited version of this idea exists today, in the form of a type of vehicle architecture called body-on-frame, which is typically found in pickup trucks and sport-utility vehicles (SUVs). Body-on-frame design makes it easier and less costly to create new body styles (such as crossover vehicles and extended pickup trucks) than is possible with the unibody construction commonly used for passenger cars. AUTOnomy¿s skateboard-like chassis takes the idea a step further, by enabling greater front-end design variation, more freedom with interior arrangements and more flexible chassis tuning.