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A handful of companies are working on advanced flywheel systems to power automobiles, buses and even trains. One company, U.S. Flywheel, is developing a car that uses a series of flywheels, with no gas engine at all. The flywheels would be recharged as batteries are. Rosen Motors will be first to the finish line, says Ben. "There are lots of others working on this. We think we will be there earlier and with better technology."
The flywheel in Rosen Motors' power train is something different altogether. It is a roughly 12-in. by 7-in. cylinder that hangs suspended in a vacuum from magnetic bearings and normally spins at 55,000 r.p.m.; today's cars run at an average of 2,000 r.p.m. The energy of the flywheel is stored in this rapid rotation, which generates electricity on demand. In the Rosens' power train, the flywheel works in conjunction with a gas-driven microturbine to make the car go.
The essence of the hybrid is that very little energy is wasted. Not only does the turbine re-spin the flywheel, but so does braking, which in today's cars produces energy that is lost. The same goes for fuel. With a catalytic "combustor" on the turbine that burns gas more efficiently, the power train will produce what is, by EPA standards, "zero emissions." According to the Rosens, the turbo-flywheel combination will at least double the gas mileage of the car in which it is used, produce a satisfying sound not unlike that of a Lear Jet (albeit far quieter), and push a Mercedes-Benz from 0 to 60 in a tidy six seconds flat, 0.6 seconds faster than Mercedes' own V-8 can do it.
The company expects to have a working prototype of this power train next year and even foresees limited sales to gotta-have car fanatics in 1998. But there is no way of knowing exactly how close they are to the multimillion-dollar and possibly multibillion-dollar payday that awaits them if the engine is mass produced. The hybrid works well in the lab, but the first road tests have been postponed until next year.
That's one reason many competitors in the race for a new engine remain exceedingly dubious. "I consider Rosen Motors to be a very small part of the overall flywheel effort," says Joe Beno, program manager for the electric-vehicle program at the University of Texas at Austin, whose group will put a flywheel motor in a commercial bus in Houston next year. Kevin M. Myles, director of the electrochemical technology program at Argonne National Laboratory, who has done extensive work with alternative-fuel vehicles, doesn't think the Rosens have addressed the safety problems inherent in flywheels. A wheel operating at such a high velocity can explode if knocked off-line--say by hitting a pothole--turning high-tech carbon fibers into shrapnel. "In the final analysis, the design needs a lot of work on housing and containment. I don't think he has the ultimate power train. No disrespect intended. This is simply an observation that these guys with very limited funds are trying to do what Detroit did over decades." Chrysler's flywheel failure mirrors these concerns.