It's not just a bunch of hot air. The air car will hit the streets of India in 2008.
In 2000, there was much ado about a new zero-pollution vehicle from French inventor and Formula One engine builder, Guy Nègre. His company, Motor Development International (MDI), rolled out an urban-sized car, taxi, pickup and van that were powered by an air engine.
Instead of those tiny, tiny explosions of gasoline and oxygen pushing the pistons up and down, like in a normal internal combustion engine, the all-aluminum four-cylinder air engine used compressed air for the job.
A hybrid version, using a small gasoline engine to power an onboard compressor for a constant supply of compressed air, is claimed to be able to travel from Los Angeles to New York on just one tank of gas.
The following four years saw several announcements from MDI about distribution agreements to sell the cars in several countries, including the U.S., but no vehicles were ever produced for sale.
Prospects for MDI's air car and air hybrid are looking up, however. Tata Motors, India's largest automobile company, has signed an agreement with MDI to produce the car. About 6,000 air cars will begin hitting Indian streets in August 2008, with hybrid versions scheduled for 2009.
A South Korean company, Energine Corporation, also touts its air hybrid car called the Pneumatic Electrical Hybrid Vehicle (PHEV). Like the MDI vehicle, compressed air drives the pistons, which turn the vehicle's wheels. The air is compressed using a small motor, powered by a 48-volt battery, which powers both the air compressor and an electric motor.
The compressed air is used when the car needs a lot of energy such as starting up from a stop and acceleration. The electric motor kicks in once the car has gained normal cruising speed.
An air car isn't just a bunch of hot air. Scientists from the University of California and Ford Motor Company presented a study at the 2003 SAE (Society of Automotive Engineers) World Congress that projected an air hybrid engine could improve fuel economy 64 percent in city driving and 12 percent in highway driving.