With hub-mounted motors unavailable, Hy-wire employs a single electric motor to power the front wheels. GM adopted the same 94-kilowatt (129-kW peak) fuel cell powerplant and drivetrain used in its 2001 Opel-based HydroGen3 fuel cell vehicle; instead of a 6-inch- thick chassis, this required an 11-inch skateboard that fattens to 17 inches at the rear to provide clearance for the fuel cell stack. The promised 300-mile range is currently limited to 80 miles by the capacity of Hy-wire's compressed hydrogen tanks, which top out at 5,000 psi.
The company chose a luxury sedan as the body style for Hy-wire because a utilitarian minivan shape would imply that the fuel cell system still required the volume of a large vehicle. "If you can do a car, it is obvious that you can do a taller vehicle," says Chris Borroni-Bird, who joined the Fusion group as director in 2000, cooked up the Autonomy concept last year, and then partnered with two European companies this spring to fast-track Hy-wire for the Paris show.
At the Geneva show in March, Borroni-Bird had seen the Filo drive-by-wire concept car produced by Italian design house Stile Bertone. Filo was a joint effort with the Swedish SKF Group, which builds by-wire systems for aircraft and wanted to break into the growing market for by-wire auto technology. In Filo, a single airplane-style control yoke replaced the usual steering wheel and pedals. Why not move this ready-made system into the Autonomy? By April, Borroni-Bird had struck a deal with Bertone/SKF to marry his skateboard to their by-wire technology. GM would direct the project and design the car, SKF would provide drive-by-wire control systems like the ones used in the Filo, and Bertone would assemble the final product.
Managing the transcontinental project for a September deadline was tricky, says Mohsen Shabana, the chief engineer on the Autonomy program, because there was little time to test individual systems before merging them. So the team built two rolling frames for the Hy-wire, one with battery power and one with a fuel cell, meaning the drive-by-wire systems could be tested on the frame while the more complex fuel cell problems were sorted out.
Early test drives show that concentrating weight below has yielded a very stable car. The by-wire yoke system, though, "takes a little bit of training," says Shabana. "And it would be a bit of a departure from what our customers are used to. This is an extreme way of demonstrating the capabilities of the system, not necessarily the way we will represent it in our vehicles." Translation: Expect a more conventional array in the next edition.