# US 2009/0260599 A1 · Motion coupler for a piezoelectric actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0260599 A1 - Document ID: US20090260599A1 - Status: Published application - Kind: A1 - Application number: 12/081,643 - Filed: 2008-04-18 - Published: 2009-10-22 - Earliest claimed: 2008-04-18 - Assignees: Caterpillar Inc. - Inventors: Jayaraman Krishnapura Venkataraghavan; Shriprasad Gaurishankar Lakhapati; Stephen Robert Lewis; Avinash Reddy Manubolu - Web page: https://patentgrep.com/patent/US20090260599A1 ## CPC - F02M 47/027: {Electrically actuated valves draining the chamber to release the closing pressure} - F02M 63/0026: {using piezoelectric or magnetostrictive actuators} - F02M 63/0225: {Fuel-injection apparatus having a common rail feeding several injectors (F02M63/0003 takes precedence); Means for varying pressure in common rails; Pumps feeding common rails} - F02M 2200/02: Fuel-injection apparatus having means for reducing wear - F02M 2200/26: Fuel-injection apparatus with elastically deformable elements other than coil springs - F02M 2200/306: using mechanical means - F02M 2200/70: Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF ## Abstract The present disclosure is directed to a fuel injector. The fuel injector may include a casing substantially aligned along a central axis of the fuel injector. The fuel injector may also include a control valve configured to control a flow of fuel through the fuel injector. The fuel injector may also include a piezoelectric element disposed within the casing and associated with the control valve. The fuel injector may further include a motion coupler disposed between the control valve and the piezoelectric element the motion coupler configured to affect shock to reduce microscopic fractures within the piezoelectric element. ## Claims ### Claim 1 A fuel injector, comprising: a casing substantially aligned along a central axis of the fuel injector; a control valve configured to control a flow of fuel through the fuel injector; a piezoelectric element disposed within the casing and associated with the control valve; and a motion coupler disposed between the control valve and the piezoelectric element, the motion coupler configured to reduce shock within the piezoelectric element. ### Claim 2 (depends on 1) The fuel injector of claim 1, further including an engagement device connected to the piezoelectric element, the engagement device configured to distribute a loading force from the piezoelectric element through an annular protrusion to the motion coupler. ### Claim 3 (depends on 2) The fuel injector of claim 2, wherein the loading force from the piezoelectric element is distributed by the annular protrusion to an outer radial portion of the motion coupler, the outer radial portion configured to deflect toward the control valve. ### Claim 4 (depends on 1) The fuel injector of claim 1, wherein the motion coupler has four arms, each arm extending outward from a hub toward the casing and configured to bend to reduce shock within the piezoelectric element. ### Claim 5 (depends on 1) The fuel injector of claim 1, wherein the motion coupler has at least two arms, each arm extending outward from the central axis toward the casing and configured to bend to reduce shock within the piezoelectric element. ### Claim 6 (depends on 1) The fuel injector of claim 1, further including an engagement device connected to the piezoelectric element, the engagement device having an annular protrusion arranged in alignment with the central axis and configured to engage the motion coupler. ### Claim 7 (depends on 6) The fuel injector of claim 6, wherein an interface between the engagement device and the motion coupler includes a void, the void being substantially in line with the piezoelectric element along the central axis. ### Claim 8 (depends on 1) The fuel injector of claim 1, further including a piston disposed between the control valve and the piezoelectric element, the piston configured to reduce shock within the piezoelectric element. ### Claim 9 (depends on 8) The fuel injector of claim 8, wherein the motion coupler is connected to the upper piston, such that the motion coupler and piston move together. ### Claim 10 (depends on 1) The fuel injector of claim 1, wherein the first distance is approximately equal to a sum of the second distance and a deflection of the motion coupler. ### Claim 11 A fuel injector, comprising: a casing substantially aligned along a central axis of the fuel injector; a piezoelectric element disposed within the casing and configured to expand a first distance along the central axis; a control element disposed along the central axis, the control element configured to move a second distance and affect a flow of fuel through the fuel injector, the second distance not equal to the first distance; and a piston slidably disposed between the piezoelectric element and the control element, the piston configured to transfer motion from the piezoelectric element to the control element. ### Claim 12 (depends on 11) The fuel injector of claim 11, wherein the first distance is approximately equal to a sum of the second distance and a change in length of the piston. ### Claim 13 (depends on 11) The fuel injector of claim 11, wherein the piston is configured to reduce shock within the piezoelectric element. ### Claim 14 (depends on 11) The fuel injector of claim 11, further including a motion coupler disposed between the piston and the piezoelectric element, the motion coupler configured to reduce shock within the piezoelectric element ### Claim 15 A method of injecting fuel, comprising: pressurizing fuel; selectively energizing a piezoelectric element to translate a first distance; absorbing a portion of the first distance and reducing shock within the piezoelectric element; and translating a piston a second distance to affect a flow of pressurized fuel to be injected, the second distance having a magnitude that is less than the magnitude of the first distance. ### Claim 16 (depends on 15) The method of claim 15, further including providing a motion coupler that traverses a gap by moving the first distance, the gap configured to reduce stress associated with temperature variations. ### Claim 17 (depends on 15) The method of claim 15, further including directing a loading force caused by the piezoelectric element to an outer radial portion of a motion coupler to increase deflection and to reduce shock within the piezoelectric element. ### Claim 18 (depends on 15) The method of claim 15, wherein selectively energizing the piezoelectric element includes expanding the piezoelectric element after pressurized fuel is injected. ### Claim 19 A power system, comprising: an engine; a pump fluidly connected to the engine and configured to pressurize fuel; a fuel injector disposed between the pump and the engine, the fuel injector configured to receive a pressurized fuel from the pump and to deliver an injection of the pressurized fuel to the engine; a piezoelectric element disposed within the fuel injector and movable a first distance; and a motion coupler coupled to the piezoelectric element, the motion coupler configured to move a second distance, the second distance having a magnitude less than the magnitude of the first distance. ### Claim 20 (depends on 19) The power system of claim 19, further including a control element movable to control the injection of the pressurized fuel from the pump to the engine, the control element coupled to the motion coupler and configured to move the second distance. ### Claim 21 (depends on 20) The power system of claim 20, further including: an upper piston slidably disposed between the control element and the motion coupler, the upper piston configured to actuate the control element; an actuator piston disposed between the piezoelectric element and the motion coupler; and an annular protrusion connected to the actuator piston, the annular protrusion configured to distribute a loading force created by the piezoelectric element to an outer radial portion of the motion coupler. ### Claim 22 (depends on 19) The power system of claim 19, wherein the motion coupler has a plurality of arms configured radially from a center of the motion coupler, the plurality of arms configured to deflect as a function of a difference between the first distance and the second distance.