Patent ID: 8512006

Claim:
A system for controlling the flow and pressure of a variable displacement pump, comprising: a variable displacement pump having an inlet passage, and an outlet passage; a first chamber for controlling the displacement of said variable displacement pump; a second chamber for controlling the displacement of said variable displacement pump; a fluid control device for receiving fluid from said outlet passage, and selectively delivering fluid to said second chamber, and fluid is delivered from said inlet passage to said outlet passage from said variable displacement pump, fluid is delivered from said outlet passage to said first chamber and said fluid control device, and when fluid pressure is greater in said first chamber relative to said second chamber, the displacement of said variable displacement pump will decrease, and when fluid pressure is greater in said second chamber relative to said first chamber, the displacement of said variable displacement pump will increase; wherein said fluid control device includes a solenoid valve module having a pressure regulator valve stage including: a spool disposed within a bore, said spool having a spool supply port and a spool control port; a housing supply port in continuous fluid communication with said spool supply port and selectively in varying fluid communication with said spool control port, said housing supply port in fluid communication with and receives fluid from said outlet passage; a housing control port in continuous fluid communication with said spool control port, and said second chamber; a spool spring operably associated with said spool, said spool spring disposed within a first fluid chamber, said first fluid chamber in fluid communication with said spool supply port; a second fluid chamber in fluid communication with, and receives fluid pressure from, said outlet passage; and a housing drain port selectively in varying fluid communication with said spool control port, and under low fluid pressure, said spool spring disposed in said first fluid chamber biases said spool such that said spool control port is in substantially reduced fluid communication with said housing drain port, and said spool supply port will receive fluid pressure from said housing supply port to deliver fluid pressure to said spool control port such that said spool control port will deliver fluid to said housing control port, said first fluid chamber will receive fluid pressure from said spool supply port, and said second fluid chamber will receive fluid from said outlet passage.