# US 7,610,902 B2 · Low noise fuel injection pump > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,902 B2 - Document ID: US7610902B2 - Status: Granted - Kind: B2 - Application number: 11/952,265 - Filed: 2007-12-07 - Published: 2009-03-12 - Granted: 2009-11-03 - Earliest claimed: 2007-09-07 - Assignees: GM Global Technology Operations LLC - Inventors: John M. Beardmore; Thomas V. Timmons - Web page: https://patentgrep.com/patent/US7610902B2 ## CPC - F02M 59/102: {Mechanical drive, e.g. tappets or cams (F02M45/063 takes precedence)} - F02M 59/44: Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; {Pumps having transducers, e.g. to measure displacement of pump rack or piston} - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF ## Abstract A fuel pump assembly has a bushing defining a pumping chamber, a plunger, a cam follower piece, and a compliance device for absorbing noise by increasing either or both of a hydraulic and/or a mechanical compliance of the fuel pump assembly. The compliance device may includes a spring washer or a press-fit spring. The pump bushing and/or plunger may include a cavity as the compliance device for increasing dead volume, the cavity being in fluid communication with the pumping chamber via an orifice. A deflectable or movable mechanism is positioned within a cavity for increasing dead volume, and a solenoid varies a diameter of the orifice. The moveable mechanism includes a poppet valve having a switching pressure related to engine speed. A vehicle includes an engine, transmission, fuel rail, and a fuel pump assembly configured with at least one compliance device for absorbing a hydraulic noise component. ## Claims ### Claim 1 A fuel pump assembly for pressurizing an amount of fuel, the pump assembly comprising: a pump bushing defining a pumping chamber; a plunger disposed within the pumping chamber, and that is moveable within the pumping chamber for pressurizing the amount of fuel, the plunger having a primary axis of motion; a cam follower piece in continuous contact with the plunger and moveable therewith along the primary axis in response to motion of an engine component; and at least one compliance device configured for absorbing a hydraulic noise component along the primary axis; wherein the at least one compliance device includes a cavity adapted for use as a hydraulic accumulator for increasing a dead volume within at least one of the pump bushing and the plunger, the cavity being in fluid communication with the pumping chamber via a control orifice. ### Claim 2 (depends on 1) The fuel pump assembly of claim 1, wherein the at least one compliance device includes a spring for providing a predetermined spring force along the primary axis of motion. ### Claim 3 (depends on 2) The fuel pump assembly of claim 2, wherein the spring is selected from the group consisting of a spring washer and a press-fit spring device. ### Claim 4 (depends on 1) The fuel pump assembly of claim 1, further comprising a solenoid device configured for selectively varying a diameter of the control orifice. ### Claim 5 (depends on 1) The fuel pump assembly of claim 1, further comprising a moveable mechanism that is positioned within the cavity, the moveable mechanism being operable for moving in one direction to thereby increase a volume of the cavity, and in another direction to thereby decrease the volume of the cavity. ### Claim 6 (depends on 5) The fuel pump assembly of claim 5, wherein the cavity is positioned within the pump bushing, and wherein the moveable mechanism is selected from the group consisting of a piston accumulator device and a thin disc absorber device. ### Claim 7 (depends on 5) The fuel pump assembly of claim 5, wherein the cavity is positioned within the plunger, and wherein the moveable mechanism includes a valve operable for selectively admitting a portion of the amount of fluid into the cavity in response to a predetermined condition. ### Claim 8 (depends on 7) The fuel pump assembly of claim 7, wherein the valve is a poppet valve having a calibrated switching pressure, and wherein the predetermined condition is a threshold engine speed corresponding to the calibrated switching pressure. ### Claim 9 A high-pressure fuel pump assembly comprising: a pump bushing defining a pumping chamber; a plunger that is moveable within the pumping chamber for pressurizing an amount of fuel, the plunger and the pump bushing sharing a common axis; a cam follower piece having a cavity formed in one end, the cam follower piece being adapted for continuous dynamic contact at another end with a moveable engine component; wherein the cam follower piece includes a first compliance device that is configured for absorbing a hydraulic noise component along the common axis, and wherein the first compliance device is one of a spring washer and a press-fit spring device providing a predetermined spring force along the common axis of motion for achieving the absorbing of the hydraulic noise component. ### Claim 10 (depends on 9) The high-pressure fuel pump assembly of claim 9, wherein at least one of the pump bushing and the plunger includes a cavity adapted as a second compliance device which acts as a hydraulic accumulator for increasing a dead volume within the pump bushing, and wherein the cavity is in fluid communication with the pumping chamber via a control orifice. ### Claim 11 (depends on 10) The high-pressure fuel pump assembly of claim 10, wherein the cavity is positioned within the pump bushing and encloses a moveable mechanism selected from the group consisting of a piston accumulator device and a thin disc absorber device. ### Claim 12 (depends on 10) The high-pressure fuel pump assembly of claim 10, further comprising a solenoid device operable for selectively varying a diameter of the control orifice. ### Claim 13 A vehicle comprising: an internal combustion engine; a transmission operatively connected to the internal combustion engine for propelling the vehicle; a fuel rail having at least one fuel injector device configured for injecting an amount of pressurized fuel into the internal combustion engine for combustion therein; and a fuel pump assembly for delivering the amount of pressurized fuel to the fuel rail, the fuel pump assembly having a pump bushing defining a pumping chamber and a plunger that is moveable within the pumping chamber for pressurizing an amount of fuel to produce the amount of pressurized fuel; wherein the fuel pump assembly is configured with at least one compliance device configured for absorbing a hydraulic noise component within the fuel pump assembly, wherein the at least one compliance device includes a cavity adapted for use as a hydraulic accumulator for increasing a dead volume within at least one of the pump bushing and the plunger, the cavity being in fluid communication with the pumping chamber via a control orifice. ### Claim 14 (depends on 13) The vehicle of claim 13, wherein the at least one compliance device includes a spring positioned for absorbing the hydraulic noise component along an axis shared by the pumping chamber and the plunger. ### Claim 15 (depends on 13) The vehicle of claim 13, further comprising a moveable mechanism positioned within the hydraulic accumulator cavity, the moveable mechanism being selectively moveable for alternately increasing and decreasing an available portion of a volume of the cavity.