Patent ID: 7726948

Claim:
A pump system including a control system for controlling a variable flow pump for controlling oil flow and oil pressure in a hydraulic circuit in an engine, comprising: a pump member; an eccentric ring disposed in a housing, said eccentric ring capable of controlling the flow generated by the pump member; a decrease chamber formed in said pump system by said eccentric ring and said housing, said decrease chamber in continuous fluid communication with the discharge of said pump member and operably associated with said eccentric ring such that as the amount of fluid in said decrease chamber increases and the amount of pressure in said decrease chamber increases, said eccentric ring moves in said housing, and the displacement of said pump system will decrease; a channel extending through said pump system, said channel operable for placing said discharge of said pump member in continuous fluid communication with said decrease chamber; an increase chamber formed in said pump system by said eccentric ring and said housing, and operably associated with said eccentric ring such that as the amount of fluid in said increase chamber increases and the amount of pressure in said increase chamber increases, said eccentric ring moves in said housing, and the displacement of said pump system will increase; a pressure regulator valve stage in fluid communication with said increase chamber and providing a reference pressure to said increase chamber that acts against the pressure in said decrease chamber to determine the position of said eccentric ring; and a solenoid valve stage for hydraulically actuating said pressure regulator valve stage.