Abstract: An apparatus for preventing noise from occurring due to cavitation in a power steering pump during low temperature start-up includes the addition of a multi-passage orifice element for adding wetted surface resistance to high viscous fluid flow downstream from a single passage outlet orifice element of a fluid flow control device and upstream of an associated steering gear or steering assist valve.

Abstract: An apparatus for preventing noise from occurring due to cavitation in a power steering pump during low temperature start-up includes the addition of a multi-passage orifice element for adding wetted surface resistance to high viscous fluid flow downstream from a single passage outlet orifice element of a fluid flow control device and upstream of an associated steering gear or steering assist valve.

Abstract: A balanced rotary vane pump for a motor vehicle power steering system includes a rotor having fifteen vanes disposed in a three lobe cam ring. Three inlet ports and three outlet ports disposed in equally spaced pairs provide fluid communication to the three lobes of the cam ring. Because the subject vane pump provides a significantly larger number of pump pulses per revolution which are more closely spaced in time and may define smaller volumes, the pulsatile nature of the output and thus vibration as well as the excitation of sympathetic vibration is greatly reduced.

Abstract: A variable displacement pump (28) having a combination inlet port (71) and an outlet (76) formed integrally on the rear body (32). By integrating the combination inlet port (71) and outlet (76) on the rear body (32), this invention simplifies the manufacture of the pump (28) as compared with known variable displacement pumps.

Abstract: A balanced rotary vane pump for a motor vehicle power steering system includes a rotor having fifteen vanes disposed in a three lobe cam ring. Three inlet ports and three outlet ports disposed in equally spaced pairs provide fluid communication to the three lobes of the cam ring. Because the subject vane pump provides a significantly larger number of pump pulses per revolution which are more closely spaced in time and may define smaller volumes, the pulsatile nature of the output and thus vibration as well as the excitation of sympathetic vibration is greatly reduced.

Abstract: A variable displacement pump 28 having an electronically modulated solenoid relief valve 100 for controlling fluid flow into the pump 28. An engine control module coupled to the electronic relief valve 100 monitors vehicle speed and steering wheel turning rate change directs the solenoid relief valve 100 to adjust the pressure of fluid displacing a movable cam ring 44 within the pump 28 to provide for greater fluid flow when evasive maneuvers may be required and lesser fluid flow when low steering efforts are needed, thus resulting in energy and fuel savings.