| 摘要 |
A recirculation valve 15 for a pump 68 comprising a regulator spool 16, a first resilient biasing means 52 biasing the regulator spool in a first position in which flow of liquid from a first port of the pump to a second port of the pump is prevented, and a control valve 18 which controls the force required to move the regulator spool against the first resilient biasing means to a second position in which said flow is enabled. Preferably the control valve is an electromagnetic valve and comprises an on/off or proportional solenoid 78, a second resilient biasing means 76 and a vent. Also claimed is a pump, a method of controlling the recirculation of liquid between a first port and a second port, an internal combustion engine and a vehicle. The invention enables the pressure at which oil is recirculated to be varied according to the operating conditions of an engine by varying the voltage through the control valve. |
