Air springs are powered by a compressor, which maintains a supply of pressurized air to operate the shocks. Power from the car's alternator runs an electric motor, which turns a screw or a turbine. This pulls in air from the outside into a reservoir. A pressure detector in the reservoir maintains air pressure. If the pressure drops too low, the reservoir turns the compressor on. When the pressure reaches the right level, the compressor turns off.
Each wheel has an independent air shock. The shock is either a durable, pressurized bag or a piston with compressed air inside. When the car hits a bump or turns, the force presses down on the wheel, which presses the air shock. The compressed air in the shock pushes back, resisting and absorbing the jolt. This helps to maintain control by keeping the wheel from bouncing up and down off the road. It also makes the ride feel smooth and comfortable, and helps protect the car from damage.
Usually, the shock on each wheel has a separate sensor to control its own pressure. When a shock needs more pressure, a valve opens from the reservoir to energize it. Shocks can also let off pressure by opening a valve to the outside. If the car is going around a turn, the shocks on the outside will charge up to stop the car from tipping to the outside. This keeps the ride somewhat smoother and more level than with other types of shocks. Some air shocks also incorporate hydraulic systems that can raise and lower the ride height. You can raise the car up for rough, bumpy roads, then lower it again for better performance on the highway.
