Share this story
Close X
Switch to Desktop Site

Flywheel Technology May Give A Boost to Electric Car Hopes

Power is stored in kinetic energy rather than in chemical form

WHAT has four wheels, runs on batteries, but is too big to fit in the palm of your hand?

The AFS20 - a new ``luxury'' electric car that developers predict will replace tens of thousands of gasoline-powered vehicles in time to meet California and Northeast zero-emission vehicle (ZEV) regulations in 1998.

About these ads

The unveiling of the AFS20 at the Los Angeles Auto Show today comes at a time when many major automakers, claiming that they cannot build an electric car cost-efficiently are seeking to block ZEV regulations. The regulations dictate that 2 percent of the cars sold in California in 1998 must not emit pollution.

The AFS20 was designed in an automotive engineering joint venture between American Flywheel Systems Inc. (AFS) in Bellevue, Wash., and an auto developer in Detroit.

Except for General Motors' GM Impact 3, there has never been a mass-produced electric vehicle, says Edward Furia, chairman and chief executive of AFS. But unlike the GM Impact 3, which is powered by a lead-acid battery, the AFS20 is powered by a flywheel battery. The battery was designed by AFS, which holds the patents for the battery, and is built by Honeywell Inc. of Minneapolis. AFS and Honeywell expect to finish building the flywheel battery by 1995, says Mr. Furia, a former Environmental Protection Agency official.

But finding someone to manufacture the car is AFS's current challenge. Furia says he would rather devote his company's resources to developing new technology. The first car will cost millions to produce, but mass production will drive the cost down to about $30,000 a car, he predicts.

``For 80 years we have been trying to make up for a very poor design,'' Furia says, referring to a gas-powered car. Electric cars can shed 1,400 pounds without the standard fluids, engine, transmission, and drive shaft, he says.

Kinetic energy storage

AFS estimates that about 20 flywheels, each nine inches in diameter and weighing about 30 pounds, would be needed to power a car the size of the AFS20.

About these ads

When a driver presses on the accelerator, a controller ``draws down'' the energy from the spinning flywheels. The flywheels spin slower and slower, using the energy to propel the car.

When the driver brakes, another motor alternator decelerates the car and sends energy back into the flywheel system through the controller, recharging the flywheels.

One of the biggest advantages of flywheel batteries over electric and gas-powered sources is that they have a substantially better range compared to chemical batteries, says Edward Zorzi, vice president of engineering and technology at AFS. The lead-acid battery in the Impact has a range of about 80 miles per charge. The flywheel battery can travel about 350 miles on one charge and accelerate from 0 to 60 miles per hour in 6.5 seconds.

Flywheels also have a 25-year life cycle and can be recharged in about 15 minutes, compared to the 3- to 5-year life cycle of chemical batteries that take 4 to 8 hours to recharge. Flywheels are unaffected by low temperatures, do not corrode or produce toxic waste, require low maintenance, and are not explosion hazards.

The potential for flywheel batteries extends well beyond electric cars, Dr. Zorzi says. A flywheel battery could be used in stationary systems. For example, utilities could use flywheels to store energy for use at peak times. The flywheel could also store energy generated from wind and solar power, or store energy for factories, cable stations, and air-traffic control towers.

Skeptics remain

But some still have doubts about the expectations for battery-operated electric cars.

``An electric car is not a general-purpose car; it's a special purpose car for short distances, moderate driving, and good climate,'' says Marc Ross, a physics professor at the University of Michigan at Ann Arbor. The all-electric car is a ``very limited vehicle,'' he says. ``In any unusual driving situation or even in plain high speeds, you'd always be [in danger of] running out of energy.''

While the flywheel battery has reduced the time it takes to recharge and has increased the distance a car can travel, Mr. Ross is not convinced. He predicts that flywheels will be a supplementary and not primary source of power in electric cars. Hybrid vehicles would contain both a fuel engine and an electric battery.

No one is saying it cannot be done, Furia contends. ``The only voices of skepticism are - `Can it be done economically, and can it be done in a cost-effective way.' ''