When General Motors rolled out its "skateboard" vision for a fuel cell car at the 2002 Detroit auto show in January, there was buzz, and there was a big question. The skateboard concept, called Auto-nomy, was the product of GM's Design and Technology Fusion Group, and it radically reordered automobile physiology: Fuel cells, hydrogen, motor, and brakes were all crammed into a 15-foot-long, 6-inch-thick chassis onto which modular car bodies could be snapped. Drive-by-wire controls would plug into the skateboard's computer brain through a docking port. With all of the important mechanicals belowdecks, the car could be configured for maximum space and utility. An owner could trade in a sedan for a pickup by simply having the new body snapped onto his skateboard.
(Left) Fuel cell and by-wire technology frees engineers to flatten the chassis into an 11-inch- thick pancake of steel and wires. from the rear of the platform, the by-wire brakes (1) are activated by a computer-controlled signal, not hydraulic pressure. the fuel cell stack (2) creates electricity from hydrogen, which releases its excess heat and water vapor via metal fins on the radiator (3). Hydrogen, ostensibly from a refueling station in a town near you, enters through a valve on the side of the vehicle (4) and replenishes three compressed hydrogen tanks (5). A high priority of hydrogen storage research is ensuring these don't leak during a crash. Two types of supports connect the skateboard to the passenger cabin: body mounts (6) provide a strong physical connection, and the universal docking port (7) links cockpit controls to computerized systems on the platform. The by-wire inputs snake through this port on their way to the main by-wire system controls (8), which send commands to the brakes, electric engine (9), and by-wire steering rack (10). Future Hy-wire prototypes may incorporate four smaller engines, one per wheel, as in the autonomy concept.
Bold, no doubt. But the question was: Is this doable? Even GM conceded that the technology did not exist to get the fuel cell and hydrogen tank into a 6-inch skateboard, and might not for years. Nor were the powerful, hub-mounted electric motors-one for each wheel in the Autonomy configuration-available.
GM did promise, however, to show a proof-of-concept vehicle before the end of this year, and at the recent Paris Motor Show the company rolled out a driveable prototype called Hy-wire (HYdrogen meets by-WIRE, get it?). The images on these pages provide a fascinating look at how an ambitious vision is tweaked and compromised as a company moves from concept to working prototype with provisional technology in hand and an eye on production in distant 2010.
http://www.popsci.com/cars/article/2002-10/hy-wire-act
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