Motorcycles Designed to Run on Air

Aug. 14, 2008 -- We may be driving on air in the next few years. That is, we may be driving vehicles powered by compressed air, instead of gasoline or diesel fuel.

Researchers Yu-Ta Shen and Yean-Ren Hwang of the National Central University in Taiwan have developed an air-powered motorcycle, which uses the energy in compressed air, rather than gas, to drive the motor.

"In Taiwan, air pollution is a very serious problem in the city," Hwang said. Twenty percent of all air pollution comes from motorcycles, he added, especially carbon monoxide and unburned hydrocarbons. These emissions are worse from motorcycles and scooters than cars.

Since the only thing coming out of the new motorcycle's tailpipe is air, large-scale adoption of the new technology could take a big bite out of air pollution in Taiwan, where motorcycles are the most popular form of transportation, or in other places where motorcycles represent a large proportion of traffic.

The motorcycle would still require energy to compress the air needed to power the engine. The amount of pollution associated with that energy will depend on what kind of a power plant provides electricity to the area in question.

The current prototype can hold a little more than two and a half gallons of compressed air, which would carry the bike and driver about three-quarters of a mile.

In the future, the tank size will be increased three to four times, and the maximum pressure the tank can hold will be increased so that the motorcycle could go almost 20 miles without a refill, Hwang said, "which would be adequate for usage in the city. We would need an air compressor to refuel, most likely at a fueling station."

They published their work in the journal Applied Energy.

Other air-powered vehicle experts are not convinced that a motorcycle is the best use of the technology.

"We don't think it's a viable product because you're talking about a very, very limited amount of compressed air you can put on a bike," said Shiva Vencat, Executive Vice President of MDI, Inc. in New Paltz, N.Y., and CEO of Zero Pollution Motors, who has licensed MDI's air vehicle technology.