Patent ID: 6647965
Filing Date: 2003-11-18
Classification: F01L,F02M,F04B,Y10T

Abstract:
A pump assembly for an internal combustion engine of the type having one or more devices actuated by high-pressure liquid, an outlet passage connected to the one or more devices, a source of liquid, and an ECM; the pump assembly comprising a variable output high-pressure pump having a pump inlet port, and a pump outlet port connected to the outlet passage; a hydraulic inlet throttle valve having an inlet throttle valve inlet port connected to the source, an inlet throttle valve outlet port connected to the pump inlet port, a first spool moveable between an open position and a closed position, a spring biasing the first spool toward the open position, such spool including an inlet throttle valve piston forming one wall of a hydraulic chamber wherein the pressure of liquid in the chamber biases the first spool toward the closed position; a three-way valve having a three-way valve inlet port connected to the outlet passage, a three-way valve drain port connected to the source, a work port connected to the hydraulic chamber of the inlet throttle valve, and a second spool moveable between a first position in which the work port is connected to the drain port, a null position in which the work port is closed or substantially closed, and a second position in which the work port is connected to the three-way valve inlet port; and first means for shifting the second spool toward the first position when the pressure in the outlet passage is less than the desired pressure in the outlet passage, for maintaining the three-way valve spool in the null position when the pressure in the outlet passage is equal to the desired pressure in the outlet passage, and for shifting the three-way valve spool toward the second position when the pressure in the outlet passage is greater than the desired pressure in the outlet passage.