Variable oil pumps from SHW adjust the flow rate to the oil requirements for the respective engine speed and temperature range of the engine. They do this either by moving the pump wheels towards each other axially or, in the case of a vane pump, by adjusting the adjustment ring in the pump housing. If the engine needs less oil, the flow rate of the pump reduces accordingly. This makes them different to fixed displacement oil pumps.
SHW develops and produces various models of variable oil pumps, such as regulated pumps, the external gear pumps or vane pumps. In this way they address the requirements of the various types of engine. In addition, oil pumps can be combined with vacuum pumps and/or balancer shafts.
A map-controlled oil pump is a special form of a variable oil pump that possesses an electromagnetic control valve. The map stores the target pressure values that the pump should attain. These values are based on the operating parameters of the combustion engine. At the same time, the map-controlled pump is networked to the engine control unit on-board the vehicle. In this way it can set the engine oil pressure to the required setting regardless of its current operating condition. The oil flow is regulated by the electromagnetic control valve.