# US 9,435,281 B2 · Method for reducing performance variation of an electromagnetically-activated actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,281 B2 - Document ID: US9435281B2 - Status: Granted - Kind: B2 - Application number: 14/675,925 - Filed: 2015-04-01 - Published: 2015-10-08 - Granted: 2016-09-06 - Earliest claimed: 2014-04-04 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Scott E. Parrish; Ronald J. Zink - Web page: https://patentgrep.com/patent/US9435281B2 ## CPC - F02D 41/20: Output circuits, e.g. for controlling currents in command coils - F02D 19/0623: {Failure diagnosis or prevention; Safety measures; Testing} - F02D 41/22: Safety or indicating devices for abnormal conditions {(in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809)} - F02D 41/221: {relating to the failure of actuators or electrically driven elements} - F02D 41/222: {relating to the failure of sensors or parameter detection devices} - F02D 41/402: {Multiple injections} - F02D 2041/202: {characterised by the control of the circuit} - F02D 2041/2051: {using voltage control} - F02D 2041/2055: {with means for determining actual opening or closing time} - F02D 2041/2072: {Bridge circuits, i.e. the load being placed in the diagonal of a bridge to be controlled in both directions} - F02D 2041/389: {for injecting directly into the cylinder} - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) ## Abstract A method for reducing performance variation of an electromagnetically-activated actuator having an electrical coil and an armature includes providing actuator activation signals to the electromagnetically-activated actuator. The signals include current driven through the electrical coil in a first direction. The method detects unacceptable response variations in the armature to equivalent actuator activation signals. And, subsequent to detection of unacceptable response variations in the armature, current is driven through the electrical coil in a direction opposite that of the first direction following actuator activation signals. ## Claims ### Claim 1 A method for reducing performance variation of an electromagnetically-activated actuator including an electrical coil and an armature, comprising: providing actuator activation signals to the electromagnetically-activated actuator comprising current driven through the electrical coil in a first direction; detecting unacceptable response variations in the armature to equivalent actuator activation signals; and subsequent to detection of unacceptable response variations in the armature, driving current through the electrical coil in a direction opposite that of the first direction following actuator activation signals. ### Claim 2 (depends on 1) The method of claim 1 wherein detecting unacceptable response variations in the armature comprises: subsequent to each actuator activation signal, sensing a respective voltage inflection in the electrical coil indicative of the armature reaching a rest position; and detecting variability in timing among the respective voltage inflections, wherein unacceptable response variations correspond to unacceptable variability in timing. ### Claim 3 A method for reducing performance variation of an electromagnetically-activated fuel injector including an electrical coil and an armature, comprising: providing injector activation signals to the electromagnetically-activated fuel injector comprising driving a first current through the electrical coil in a first direction; subsequent to each injector activation signal, sensing a respective voltage inflection in the electrical coil indicative of the armature reaching a rest position; detecting variable timing among the respective voltage inflections, wherein unacceptable response variations correspond to unacceptable variable timing; and subsequent to detection of unacceptable response variations, driving a second current through the electrical coil in a direction opposite that of the first direction and following injector activation signals. ### Claim 4 (depends on 3) The method of claim 3 wherein detecting variable timing among the respective voltage inflections comprises detecting variable timing between adjacent respective voltage inflections. ### Claim 5 (depends on 3) The method of claim 3 wherein driving the second current through the electrical coil comprises: increasing the second current corresponding to a present detection of a respective unacceptable response variation relative to the second current corresponding to a prior detection of a respective unacceptable response variation. ### Claim 6 (depends on 3) The method of claim 3 further comprising detecting stable timing among the respective voltage inflections and determining a fuel mass delivered by the injector based upon said stable timing. ### Claim 7 (depends on 6) The method of claim 6 further comprising adjusting the injector activation signals to converge the fuel mass delivered by the injector to a desired fuel mass to be delivered by the injector. ### Claim 8 (depends on 6) The method of claim 6 further comprising storing the second current sufficient to establish stable timing among the respective voltage inflections to a non-volatile memory device. ### Claim 9 (depends on 7) The method of claim 7 further comprising storing the adjusted injector activation signals to a non-volatile memory device. ### Claim 10 A system for controlling actuation of a fuel injector, comprising: a fuel injector comprising an electrical coil and an armature; an injector driver responsive to an injector command signal for driving current through the electrical coil; and a control module configured to: actuate the injector by providing the injector command signal to the injector driver effective to drive a first current through the electrical coil in a first direction; subsequent to the first current through the electrical coil, sense a voltage inflection in the electrical coil indicative of the armature reaching a rest position; determine a timing of the voltage inflection, detect a timing variation between the timing of the voltage inflection and a timing of a prior voltage inflection corresponding to an immediately prior injector actuation; determine an unacceptable injector response variation based on an unacceptable timing variation; and subsequent to detection of the unacceptable injector response variation, provide the injector command signal to the injector driver effective to drive a second current through the electrical coil in a direction opposite that of the first direction. ### Claim 11 (depends on 10) The system of claim 10 wherein the injector command signal to the injector driver effective to drive the second current through the electrical coil is effective to increase the second current corresponding to a present injector actuation relative to the second current corresponding to the immediately prior injector actuation. ### Claim 12 (depends on 10) The system of claim 10 wherein the control module is further configured to detect a timing stability between the timing of the voltage inflection and the timing of the prior voltage inflection corresponding to the immediately prior injector actuation and determine a fuel mass delivered by the injector based upon said timing stability. ### Claim 13 (depends on 12) The system of claim 12 wherein the control module is further configured to adjust the injector command signal to converge the fuel mass delivered by the injector to a desired fuel mass to be delivered by the injector. ### Claim 14 (depends on 12) The system of claim 12 wherein the control module is further configured to store the second current sufficient to establish said timing stability between the respective voltage inflections to a non-volatile memory device. ### Claim 15 (depends on 13) The system of claim 13 wherein the control module is further configured to store the adjusted injector activation signal to a non-volatile memory device.