Air-Driven Automobile Engine

Can a normal four-cylinder gasoline engine actually operate on compressed air instead of gasoline as its energy source?

Answer

Yes. Many companies worldwide have been operating compressed-air-driven cars using a standard gasoline four cylinder engine but replacing the gasoline fuel input with compressed air from a tank. Of course, there is no combustion, so the electrical supply for the spark plugs is not needed, nor will there be any need to change the oil very often. The compressed-air tank is stored in the trunk.

The piston upstroke compresses and heats the atmospheric air in the cylinder chamber until just about top dead center, when cool compressed air is injected to drive the piston down and turn the crankshaft. The process repeats itself until the compressed air is depleted. The exhaust is just cool air. The horsepower rating is about 35 horsepower for some models, but the value will increase to more practical values with further development. Using traditional electricity sources to compress the air, there will be some carbon dioxide air pollution for the overall process, but only about a fifth or less that of conventional autos.

Perhaps the best-known air-powered car is that designed by French inventor and engineer Guy Negre for Motor Development International (MDI) in France. The car has a maximum speed of about 110 kilometers per hour and can travel about 300 kilometers at a cost of less than a cent per kilometer. (Details can be found on the Internet.)