Continuous Variable Displacement Oil Pump

The variable displacement oil pump is designed to have the ability to change its running displacement upon command. Working together with a pressure regulation proportional solenoid valve, it can vary its displacement to produce the required oil pressure without wasting energy through bypassed oil flow or excessively high oil pressure. Therefore, its power consumption is reduced for a better fuel economy, comparing to a fixed displacement oil pump.

The oil pressure in the control chamber is balanced by the force from the pump spring in a running pump. When a given duty cycle control signal is sent to the solenoid valve, it will command a given oil pressure. If the actual oil pressure is higher than the commanded oil pressure, the solenoid valve will supply more oil to the control chamber, produce more pressure in the chamber, push the spring and the eccentric ring down, and reduce its running displacement and the oil pressure till the pressure is at the commanded level. Or vice versa, if the actual oil pressure is lower than the commanded oil pressure, the solenoid valve will supply less oil to the control chamber or even vent the chamber, produce less pressure in the chamber, bring the spring and the eccentric ring up, and increase its running displacement and the oil pressure till the pressure is at the commanded level.

The required oil pressure, i.e. the commanded oil pressure, depends on the operation conditions of the engine. Therefore, the engine runs with oil pressure at its required level without waste in such a system in order to minimize its parasitic energy loss