The electric steering pump forms part of a hydraulic power assisted steering system and is not to be confused with electric power steering, which operates without a belt-driven hydraulic pump. An electric steering pump is found in what is sometimes described as electro-hydraulic or hybrid power steering systems. This type of system uses the same source of hydraulic pressure to provide the steering assistance but the hydraulic fluid is pumped out of the reservoir by an electric steering pump rather than a belt driven by the engine.
The speed of the pump is regulated by an electric controller which has the ability to vary pump pressure and flow. This tailors the system’s contribution to the steering efforts to different driving situations. This means that the electric steering pump can operate at higher speed and thereby provide greater steering assistance when the car is being driven slowly. This is especially helpful in providing assistance when the vehicle is being parked. A further advantage is that the pump can be operated at low speed or shut down completely to provide energy savings when driving in a straight line.
The electric steering pump therefore plays an important role in operating a hydraulic power assisted steering system and is an effective alternative to an engine driven pump.