AIR CAR BY 2011

Company looks to bring air-powered cars to US
Dan Strumpf, May 25, 2009 (AP)

"Most car companies are racing to bring electric vehicles to the market. But…Zero Pollution Motors is trying to bring a car to U.S. roads by early 2011 that's powered by a combination of compressed air and a small conventional engine…[T]he ultimate goal is a price tag between $18,000 and $20,000, fuel economy equivalent to 100 miles per gallon and a tailpipe that emits nothing but air at low enough speeds.

"Elsewhere in the world, the technology is already gaining speed. The French startup Motor Development International, which licensed the technology to ZPM, unveiled a new air-powered car at the Geneva Auto Show in March. Airlines KLM and Air France are starting to test the bubble-shaped AirPod this month for use as transportation around airports."

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"Engineering experts, however, are skeptical of the technology, saying it is clouded by the caveat that compressing air is notoriously energy intensive…[T]he "air cars" plug into a wall outlet, allowing an on-board compressor to pressurize the car's air tank to 4,500 pounds per square inch. It takes about four hours to get the tank to full pressure, then the air is then released gradually to power the car's pistons.

"At speeds less than 35 mph, the car relies entirely on the air tank and emits only cold air. At faster speeds, a small conventionally fueled engine kicks in to run a heater that warms the air and speeds its release. The engine also refills the air tank, extending the range and speed…[The air car] is expected] to go about 20 miles on compressed air alone, and hundreds more after the engine kicks in, with a top speed of 96 mph…"

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"James Van de Ven, a mechanical engineering assistant professor at Worcester Polytechnic Institute who has studied compressed-air technology, said air compressors allow you to recover only 25 to 30 percent of the energy used to compress the air. The rest is lost through heat, air leakage and other forms of waste…While that's still slightly better a gasoline engine, it pales compared with the efficiencies of other alternative-fuel powertrains, like those in hybrid-electric cars, which have an efficiency closer to 80 percent…

"With four hours of charging, the air car's 5.5-kilowatt compressor would eat up 22 kilowatt-hours of electricity. That means the same energy used to turn on 10 100-watt light bulbs for 22 hours would allow the car to travel 20 miles…General Motors Corp. has said its Chevrolet Volt will use about 8 kilowatt-hours of energy to fully charge, and it will be able to travel 40 miles on battery power alone…"