Sunday, September 22, 2013

The Dark Secret of Electric Cars: Astounding Speed

His colleagues at General Motors thought he was joking when John Waters challenged them to a race: Their high powered Corvettes against his EV1, powered by nothing but an electric motor.
The EV1, the first electric car built by GM, was a nice-looking compact, but when parked beside a Corvette, it looked a little like a shy bug.
Waters had one rule. The race had to be done in a parking lot, which limited the top speed to about 30 mph. The frequent races became somewhat of a sensation, especially among high school students who would flock to the scene to see the mighty slaughter the weak.
Did Waters ever win?
"We never lost a race," he said. "The Corvettes had more horsepower, of course, so if we were racing from zero to 100 they would have smoked us."
The secret behind Water's success is the reason he is convinced electric cars will win out over the internal-combustion engine in the vehicles of the future, and that future might not be far away.
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Gasoline-powered vehicles operate at about 30 percent efficiency, and about 70 percent of the energy is eaten by heat, sound, friction and pollutants that are destroying our atmosphere.
A vehicle powered by an electric motor can operate at about 90 percent efficiency, according to Waters and numerous studies, because of instant power through torque.
A gas engine converts energy into motion by igniting fuel to move pistons and turn a crankshaft that spins a flywheel, eventually causing the wheels to turn.
But at low speed, the engine does not have enough torque -- forward movement produced by rotational motion -- to get the vehicle moving. So all that energy has to be helped by a transmission, which allows the engine to rotate faster to get the car to move, and slow down as the speed increases.
An electric motor doesn't need all that help, including the complex, heavy and expensive transmission found in today's gas-powered cars. It has as much torque from a standstill as it does at high speed.
That's called "instant torque," and it's the reason Waters' toy-like sedan could blow out a high-performance vehicle, at least from zero to 30 mph.
It's also part of the reason some of the fastest cars on the planet are now powered by electric motors, not internal-combustion engines that have been around for more than a century.
"Experimental electric cars already have achieved sustained speeds of more than 180 miles per hour, and established world speed records above 300 mph," Waters told the national meeting of the American Chemical Society earlier this month in Indianapolis.
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Waters, who developed the battery platform for the EV1 while he was with General Motors, expects to demonstrate the amazing performance of electric vehicles on a racetrack soon.
"I have no doubt that battery-powered race cars will be attracting race fans in the immediate future," he told the ACS.
The high performance of electric vehicles has been overshadowed by two major factors: range, because nobody wants to run out of juice halfway home from work, and batteries, which are expensive, heavy and require frequent charging.
Some problems will disappear through the natural course of development of a new technology, like faster charging, more remote recharging locations, and more juice in the battery. The state-of-the-art in battery technology is lithium-ion, and researchers around the world are working at a fever pitch to improve its performance.

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