Alternative Energy: Two Cylinder Air-Compression Engine

Within the next two years, you could see the first air-powered vehicle motoring through your town. Most likely, it will be the e.Volution car that is being built by Zero Pollution Motors, in Brignoles, France. The cars have generated a lot of interest in recent years, and the Mexican government has already signed a deal to buy 40,000 e.Volutions to replace gasoline- and diesel-powered taxis in the heavily polluted Mexico City.

Makers of the e.Volution are marketing the vehicle as a low pollution or zero pollution car. However, there is still some debate as to what the environmental impact of these air-powered cars will be. Manufacturers suggest that because the cars run on air they are environmentally friendly. Critics of the air-powered car idea say that the cars only move the air pollution from the car's exhaust to somewhere else, like an electrical power plant. These cars do require electricity in order for the air to be compressed inside the tanks, and fossil fuel power is needed to supply electricity.

The e.Volution is powered by a two-cylinder, compressed-air engine. The basic concept behind the engine is unique (see this page for details) -- it can run either on compressed air alone or act as an internal combustion engine. Compressed air is stored in carbon or glass fiber tanks at a pressure of 4,351 pounds per square inch (psi). This air is fed through an air injector to the engine and flows into a small chamber, which expands the air. The air pushing down on the pistons moves the crankshaft, which gives the vehicle power.

The e.Volution will be able to travel about 124 miles (200 km) before being refueled with compressed air.

Exhaust from the e.Volution vehicle's engine, seen here, will contain no pollutants.

Zero Pollution Motors is also working on a hybrid version of their engine that can run on traditional fuel in combination with air. The change of energy source is controlled electronically. When the car is moving at speeds below 60 kph, it runs on air. At higher speeds, it runs on a fuel, such as gasoline, diesel or natural gas.

Air tanks fixed to the underside of the vehicle can hold about 79 gallons (300 liters) of air. This compressed air can fuel the e.Volution for up to 124 miles (200 km) at a top speed of 60 miles per hour (96.5 kph). When your tank nears empty, you can just pull over and fill the e.Volution up at the nearest air pump. Using a household electrical source, it takes about four hours to refill the compressed air tanks. However, a rapid three-minute recharge is possible, using a high-pressure air pump.

The car's motor does require a small amount of oil, about .8 liters worth that the driver will have to change just every 31,000 miles (50,000 km). The vehicle will be equipped with an automatic transmission, rear wheel drive, rack and pinion steering and a 9.5 foot (2.89 m) wheel base. It will weigh about 1,543 pounds (700 kg) and will be about 12.5 feet (3.81 m) long, 5.7 feet (1.74 m) tall, and 5.6 feet (1.71 m) wide.

In October, the e.Volution made its public debut in Johannesburg, South Africa, at the Auto Africa Expo 2000. Zero Pollution said that the car will go on sale in South Africa in 2002, but didn't say when the car would be available in other parts of the world.