# US 7,610,898 B2 · Apparatus and method for controlling idle speed of internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,898 B2 - Document ID: US7610898B2 - Status: Granted - Kind: B2 - Application number: 11/661,097 - Filed: 2005-08-26 - Published: 2008-05-22 - Granted: 2009-11-03 - Earliest claimed: 2004-08-26 - Assignees: Toyota Jidosha Kabushiki Kaisha; Denso Corporation - Inventors: Keizo Hiraku; Noboru Takagi; Kiyoo Hirose; Hirohiko Yamada - Web page: https://patentgrep.com/patent/US7610898B2 ## CPC - F02D 41/2451: {characterised by what is learned or calibrated} - F02D 13/08: for rendering engine inoperative or idling - F02D 31/003: {for idle speed control} - F02D 41/0002: {Controlling intake air} - F02D 41/2464: {Characteristics of actuators} - F02D 2041/001: {for engines with variable valve actuation} - F02D 2041/002: {by simultaneous control of throttle and variable valve actuation} - Y02T 10/12: Improving ICE efficiencies - Y02T 10/40: Engine management systems - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An engine has a variable valve actuation mechanism that varies lift characteristics of an intake valve. An idle speed control apparatus has a control section for controlling an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed. The control section sets a control amount related to control of the intake air amount in correspondence with the lift characteristics, which are varied by the variable valve actuation mechanism. Accordingly, the engine speed in the idle state is effectively controlled in correspondence with changes of the lift characteristics. ## Claims ### Claim 1 An idle speed control method for an internal combustion engine including an intake passage, an intake valve, and a variable valve actuation mechanism that varies lift characteristics of the intake valve, the method comprising: controlling an intake air amount in the intake passage of the engine in an idle state for adjusting an actual engine speed to a target engine speed, setting a required opening degree of the intake passage in correspondence with the lift characteristics varied by the variable valve actuation mechanism, and controlling a control valve provided on the intake valve for adjusting an actual opening degree of the intake valve. ### Claim 2 (depends on 1) The method according to claim 1, comprising feedback controlling the opening degree of the intake passage in such a manner that a feedback compensation amount for the required opening degree of the intake passage is set in correspondence with the difference between the actual engine speed and the target engine speed and the lift characteristics varied are by the variable valve actuation mechanism. ### Claim 3 (depends on 1) The method according to claim 1, comprising feedforward controlling the opening degree of the intake passage in such a manner that a feedforward compensation amount for the required opening degree of the intake passage control amount is set in correspondence with the lift characteristics varied by the variable valve actuation mechanism. ### Claim 4 An idle speed control apparatus for an internal combustion engine including an intake passage, an intake valve, and a variable valve actuation mechanism that varies lift characteristics of the intake valve, the apparatus comprising: a control valve for controlling an opening degree of the intake passage, a control section for controlling the control valve to adjust an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed, wherein the control section sets a required opening degree of the intake passage in correspondence with the lift characteristics varied by the variable valve actuation mechanism. ### Claim 5 (depends on 4) The apparatus according to claim 4, wherein the control section controls a throttle opening degree. ### Claim 6 (depends on 4) The apparatus according to claim 4, wherein the control section feedforward controls the opening degree of the intake passage in such a manner that a feedforward compensation amount for the required opening degree of the intake passage is set in correspondence with the lift characteristics varied by the variable valve actuation mechanism. ### Claim 7 (depends on 6) The apparatus according to claim 6, wherein the variable valve actuation mechanism varies a lift duration angle of the intake valve as the lift characteristics, and wherein the feedforward compensation amount set by the control section becomes greater as the lift duration angle set by the variable valve actuation mechanism becomes larger. ### Claim 8 (depends on 4) The apparatus according to claim 4, wherein the control section feedback controls the opening degree of the intake passage in such a manner that a feedback compensation amount for the required opening degree of the intake passage is set in correspondence with the difference between the actual engine speed and the target engine speed and the lift characteristics are varied by the variable valve actuation mechanism. ### Claim 9 (depends on 8) The apparatus according to claim 8, wherein the engine has a crankshaft, and wherein the control section sets the feedback compensation amount in correspondence with the difference between the actual engine speed and the target engine speed, the lift characteristics are varied by the variable valve actuation mechanism, and a rotation angle of the crankshaft corresponds to a predetermined level of the lift amount of the intake valve. ### Claim 10 (depends on 8) The apparatus according to claim 8, wherein the variable valve actuation mechanism varies a lift amount of the intake valve as the lift characteristics, and wherein the feedback compensation amount set by the control section becomes greater as the lift amount set by the variable valve actuation mechanism becomes smaller. ### Claim 11 (depends on 10) The apparatus according to claim 10, wherein a feedback gain related to the feedback controlling set by the control section becomes greater as the lift amount becomes smaller. ### Claim 12 (depends on 8) The apparatus according to claim 8, wherein the feedback compensation amount is different from a predetermined reference value; the apparatus further includes a learning section for learning the difference between the feedback compensation amount and the reference value as a feedforward compensation amount; and the control section controls the opening degree of the intake passage in correspondence with the feedback compensation amount and the feedforward compensation amount. ### Claim 13 (depends on 12) The apparatus according to claim 12, wherein the learning section defines a plurality of ranges for the intake air amount, and wherein the learning section learns the feedforward compensation amount in correspondence with each of the ranges.