GM looks to leverage fuel cell flexibility

Detroit-In the fuel-cell powered AUTOnomy concept car unveiled today by GM at the International Auto Show, designers threw out any preconceived notions of adapting existing automobile configurations to simply accommodate electric propulsion and power sources. What resulted was not merely a new auto powerplant, but a revised architecture for the overall vehicle.

Starting with a clean sheet, the design engineers figured there was no reason the shape of the fuel cells and hydrogen fuel storage had to conform to any given arrangement, just merely have enough volume for adequate range and speed. With fuel cells efficiently providing electrical power (twice the efficiency of internal combustion, according to GM), the best way to use that power would be in electrically driven by-wire systems, such and steering and braking, as well as accessories such as climate control. With the driver interface thus being electrical, the engineers came up with a building block approach-why not put all the power systems in the chassis, a slender "skateboard" to which various bodies (depending on driver need and affordability) could be electrically "docked," much like a laptop computer is mated to a desktop station. The designers envision such a chassis as eventually being only 6 inches thick, for an extremely low center of gravity.

While such a concept has seemingly endless possibilities, how soon might such vehicles be tooling down the highways? According to Chris Borroni-Bird, head of Design and Technology Fusion for GM, a driveable demonstrator vehicle will be on the road by the end of the year. "This 'driver' will run on compressed hydrogen gas, at 5,000 psi. It will have a single motor powering the front wheels and be a 4 to 5 seater," he adds. Later versions will have motors on each wheel. The driver will use the SKF Filo steer-by-wire system .

Borroni-Bird says the concept "could come to fruition in, say, 10 years" with vehicles on the market, and a full hydrogen economy by the year 2020. He adds that to realize this "a breakthrough in hydrogen storage, for range, is needed. For 300 miles range, a two to threefold improvement is needed." (Range with current technology is pegged around 150 miles.)

What form a hydrogen infrastructure takes is hard to predict, although some choices come to the fore. Borroni-Bird says that natural gas is the cheapest way to make hydrogen at this time. But then again, the gasoline infrastructure now in place could be adopted to reform that fuel into hydrogen. With either base fuel, there is a question of reforming at the station (or home supply for natural gas) or onboard the vehicle. Then again, electricity, if made economical enough, could be used to breakdown water for hydrogen.

Suffice it to say, that with the AUTOnomy concept, GM designers have given the drive for more energy efficient, as well as flexible, vehicles more building blocks and not just food for thought.