The air car is the brainchild of inventor Guy Negre, who claims models will cost less than £6,000, achieve 68mph, with a range of more than 100 miles and only need an oil change every 31,000 miles.
The engine has been 10 years in development and involves two cylinders. The first takes cool air from outside the car and compresses it, which heats the air so it can then be pushed into a second cylinder. Cold compressed air is added, which expands quickly and pushes the piston down, starting the process again.
Compressed air is carried at 300 times atmosphere pressure in a tank under the car. The firm behind the idea, Motor Development International, says it can be refilled from a tyre pump at petrol stations, or overnight at home. Running costs are just over 1p a mile.
Although the firm has yet to start production, it will present its idea to potential investors at the Millennium Hotel, in Knightsbridge, London, on Friday, September 20. The firm will also be at the Paris Motor Show. MDI says the first cars will be produced by the end of this year and production licences have been granted all over the world, covering models including family cars, city cars, trucks and bikes.
It claims that in Spain, the order books already number 16,000, with a total value of more than £100 million.