Compressed Air Cars

Compressed air cars are vehicles that use motors powered by pressurized air either as a sole means of locomotion or as part of a hybrid system with combustion engine or electric motor.

A high pressure tank of compressed air is used to store energy which is released through lines or hoses to a motor which spins as the air passes through it. The throttle of the car usually controls the amount of air flowing, thus controlling the speed of the vehicle.

The first compressed air car was prototyped in the 1920s, but since the beginning, these vehicles have been plagued by range and power issues. In energy usage, compressed air cars are generally much less efficient than even fossil fueled vehicles.

Advantages / Disadvantages

The principal advantages of compressed air vehicles are that they can be refueled at home or on the road using existing infrastructure.

They are also simpler and much cheaper to make because they require no expensive batteries or complex engine to run. Compressed air also stores well and is very safe when compared to combustible liquids and gases and with caustic or acidic chemicals.

The disadvantages are also many. Because energy is being stored as a compressed gas, it's less efficiently stored than it would be if stored chemically or used directly. Further, the power output of compressed air vehicles is relatively low (when measured in torque, horsepower, or wattage) and the vehicles that use this technology are generally light and small and below highway safety standards.

Heat exchange is another big issue for compressed air vehicles. Compressed air, when released, is usually colder than ambient air and this leads to frost and other issues in the vehicle's air lines. This also causes energy exchange problems at the motor, reducing efficiency.

Overall, compressed air vehicles are generally considered a novelty by the automotive industry. Few companies make them and those that do are usually doing so as low-speed, urban vehicles.

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