Power Steering?

Power steering is a system for reducing the steering effort on cars by using an external power source to assist in turning the wheels. Most power steering systems work by using a belt-driven pump to provide hydraulic pressure to the system. This hydraulic pressure is generated by a rotary vane pump which is driven by the vehicle's engine. As the speed of the engine increases, the pressure in the hydraulic fluid also increases, hence a relief valve is incorporated into the system to allow excess pressure to be bled away.