# US 12,760,693 B2 · Method for controlling engine and engine control apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,760,693 B2 - Document ID: US12760693B2 - Status: Granted - Kind: B2 - Application number: 19/012,728 - Filed: 2025-01-07 - Published: 2025-07-17 - Granted: 2026-10-13 - Earliest claimed: 2024-01-12 - Assignees: Mazda Motor Corporation - Applicants: Mazda Motor Corporation - Inventors: Takuma Fujii; Mitsuhiro Muto; Keisuke Okihama; Ryohei Matsuo - Web page: https://patentgrep.com/patent/US12760693B2 ## CPC - F02D 41/401: {Controlling injection timing (F02D41/402 takes precedence)} - F02P 5/1502: {using one central computing unit} - 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) - F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00) ## Abstract A method for controlling an engine includes selecting a control point consisting of a combination of an injection timing of injecting fuel and an ignition timing of igniting an air-fuel mixture, corresponding to a selection on a parameter map Mlim having the injection timing as a first axis and the ignition timing as a second axis, defines a parameter region Rlim surrounded by a first limit line Li1 indicating an advance limit at which preignition is restrained, a second limit line Li2 indicating an advance limit at which smoke is restrained, a third limit line Li3 indicating an advance limit at which knocking is restrained, and a fourth limit line Li4 indicating a retard limit at which combustion stability is ensured on the parameter map Mlim, and further includes a step of selecting the control point so the ignition timing is brought to maximum advance within the parameter region Rlim. ## Claims ### Claim 1 A method for controlling an engine using a cylinder, an injector that injects fuel into the cylinder, a spark plug that ignites an air-fuel mixture containing the fuel injected from the injector, and a controller that is electrically connected to the injector and the spark plug and controls each of the injector and the spark plug, the method comprising: selecting with the controller a control point consisting of a combination of an injection timing at which the injector injects the fuel and an ignition timing at which the spark plug ignites the air-fuel mixture, corresponding to a selection on a parameter map defined by a first axis of the injection timing and a second axis of the ignition timing that is orthogonal to the first axis of the injection timing, wherein a plurality of limit lines are provided on the parameter map, each of the limit lines varying in accordance with an operating state of the engine, the plurality of limit lines include a first limit line indicating an advance limit of the injection timing for restraining preignition, a second limit line indicating an advance limit of the ignition timing for restraining smoke, a third limit line indicating an advance limit of the ignition timing for restraining knocking, and a fourth limit line indicating a retard limit of the ignition timing for ensuring combustion stability, and the plurality of limit lines define a parameter region surrounded by the plurality of limit lines on the parameter map; and selecting with the controller the control point so that the ignition timing is brought to maximum advance within a range of the parameter region. ### Claim 2 (depends on 1) The method for controlling the engine according to claim 1, further comprising: first shifting by the controller the control point onto any one of the limit lines constituting the parameter region when the control point falls outside the parameter region in response to a reduction of the parameter region; and after the first shifting, second shifting by the controller the control point repeatedly each time a combustion cycle is repeated until the ignition timing is brought to maximum advance within a range of the parameter region after the reduction. ### Claim 3 (depends on 2) The method for controlling the engine according to claim 2, wherein the first shifting includes shifting the control point onto any one of the limit lines within one combustion cycle through feedforward control based on the operating state of the engine. ### Claim 4 (depends on 1) The method for controlling the engine according to claim 1, further comprising: shifting, by the controller, the control point in repeatedly each time a combustion cycle is repeated in response to the ignition timing being brought to non-maximum advance in response to an expansion of the parameter region, until the ignition timing is brought to maximum advance within a range of the parameter region after the expansion. ### Claim 5 (depends on 1) The method for controlling the engine according to claim 1, wherein a piston is housed in the cylinder, a cavity is formed on an upper face of the piston, and the plurality of limit lines further include a fifth limit line indicating an advance limit of the injection timing for allowing the fuel injected from the injector to reach inside of the cavity. ### Claim 6 (depends on 1) The method for controlling the engine according to claim 1, wherein the plurality of limit lines further include a sixth limit line indicating an advance limit of the ignition timing for allowing the fuel injected from the injector to reach the spark plug. ### Claim 7 An engine control apparatus for controlling an engine including a cylinder, an injector that injects fuel into the cylinder, and a spark plug that ignites an air-fuel mixture containing the fuel injected from the injector, comprising: circuitry configured to select a control point consisting of a combination of an injection timing at which the injector injects the fuel and an ignition timing at which the spark plug ignites the air-fuel mixture, corresponding to a selection on a parameter map defined by a first axis of the injection timing and a second axis of the ignition timing that is orthogonal to the first axis of the injection timing, wherein a plurality of limit lines are provided on the parameter map, each of the limit lines varying in accordance with an operating state of the engine, the plurality of limit lines include a first limit line indicating an advance limit of the injection timing for restraining preignition, a second limit line indicating an advance limit of the ignition timing for restraining smoke, a third limit line indicating an advance limit of the ignition timing for restraining knocking, and a fourth limit line indicating a retard limit of the ignition timing for ensuring combustion stability, and the plurality of limit lines define a parameter region surrounded by the plurality of limit lines on the parameter map; and select the control point so that the ignition timing is brought to maximum advance within a range of the parameter region. ### Claim 8 (depends on 7) The engine control apparatus according to claim 7, wherein the circuitry is further configured to perform first shifting of the control point onto any one of the limit lines constituting the parameter region when the control point falls outside the parameter region in response to a reduction of the parameter region; and after the first shifting, perform second shifting of the control point repeatedly each time a combustion cycle is repeated until the ignition timing is brought to maximum advance within a range of the parameter region after the reduction. ### Claim 9 (depends on 8) The engine control apparatus according to claim 8, wherein the first shifting includes shifting the control point onto any one of the limit lines within one combustion cycle through feedforward control based on the operating state of the engine. ### Claim 10 (depends on 7) The engine control apparatus according to claim 7, wherein the circuitry is further configured to perform shifting of the control point repeatedly each time a combustion cycle is repeated in response to the ignition timing being brought to non-maximum advance in response to an expansion of the parameter region, until the ignition timing is brought to maximum advance within a range of the parameter region after the expansion. ### Claim 11 (depends on 7) The engine control apparatus according to claim 7, wherein a piston is housed in the cylinder, a cavity is formed on an upper face of the piston, and the plurality of limit lines further include a fifth limit line indicating an advance limit of the injection timing for allowing the fuel injected from the injector to reach inside of the cavity. ### Claim 12 (depends on 7) The engine control apparatus according to claim 7, wherein the plurality of limit lines further include a sixth limit line indicating an advance limit of the ignition timing for allowing the fuel injected from the injector to reach the spark plug.