# US 9,038,596 B2 · Method and system for pre-ignition control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,596 B2 - Document ID: US9038596B2 - Status: Granted - Kind: B2 - Application number: 13/310,437 - Filed: 2011-12-02 - Published: 2013-06-06 - Granted: 2015-05-26 - Earliest claimed: 2011-12-02 - Assignees: Ford Global Technologies, LLC - Applicants: Chris Paul Glugla; Paul Charles Mingo; Robert Sarow Baskins; Sue Kay Wagers - Inventors: Chris Paul Glugla; Paul Charles Mingo; Robert Sarow Baskins; Sue Kay Wagers - Web page: https://patentgrep.com/patent/US9038596B2 ## CPC - F02D 41/0087: {Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123)} - F02B 37/00: Engines characterised by provision of pumps driven at least for part of the time by exhaust - F02D 17/02: Cutting-out (cutting-out engines in multiple engine arrangements F02D25/04) - F02D 28/00: Program control of engines - F02D 35/021: {using an ionic current sensor} - F02D 35/027: {using knock sensors} - F02D 41/0002: {Controlling intake air} - F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)} - F02D 41/1446: {the characteristics being exhaust temperatures} - F02D 41/1475: {Regulating the air fuel ratio at a value other than stoichiometry} - F02D 41/30: Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)} - F02P 17/12: Testing characteristics of the spark, ignition voltage or current (testing of sparking plugs H01T13/60) - F02B 2075/125: {Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber} - F02D 13/0207: {changing valve lift or valve lift and timing} - F02D 13/0219: {by shifting the phase, i.e. the opening periods of the valves are constant} - F02D 19/084: {Blends of gasoline and alcohols, e.g. E85} - F02D 41/3094: {the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder} - F02D 2041/0012: {with selective deactivation of cylinders} - F02D 2200/1015: Engines misfires - Y02T 10/12: Improving ICE efficiencies - Y02T 10/30: Use of alternative fuels, e.g. biofuels - 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) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Methods and systems are provided for addressing pre-ignition that may be induced in response to actions taken to mitigate a cylinder misfire. An amount of engine load limiting applied may be adjusted to reduce the likelihood pre-ignition while also addressing component over-temperature issues. By limiting an engine load while shutting off fuel in a misfiring cylinder, and while combusting a lean air-fuel mixture in the remaining cylinders, pre-ignition induced by the misfire-mitigating lean combustion conditions can be reduced. ## Claims ### Claim 1 A method of controlling an engine for preventing pre-ignition, comprising: operating a cylinder to pump air without injected fuel while another cylinder combusts a lean air-fuel mixture; and limiting an amount of intake air charge directed into the cylinders to be less than a threshold, the limiting increased as a degree of leanness of the air-fuel mixture increases. ### Claim 2 (depends on 1) The method of claim 1, wherein the limiting is based on engine speed, the limiting increased when the engine speed is higher than a threshold speed. ### Claim 3 (depends on 1) The method of claim 1, wherein the limiting is based on exhaust temperature, the limiting increased as the exhaust temperature rises above a threshold temperature. ### Claim 4 (depends on 1) The method of claim 1, wherein the limiting includes one or more of reducing an opening of an intake throttle, increasing an opening of a turbocharger wastegate, adjusting a cylinder valve timing to reduce an intake aircharge, and increasing an amount of exhaust gas recirculation. ### Claim 5 (depends on 1) The method of claim 1, wherein the engine is a boosted engine coupled to a turbocharger, and wherein the threshold is based on a turbine inlet temperature. ### Claim 6 (depends on 5) The method of claim 5, wherein the operating is in response to a misfire event in the cylinder. ### Claim 7 (depends on 6) The method of claim 6, wherein the limiting is discontinued after a threshold duration has elapsed. ### Claim 8 (depends on 1) The method of claim 1, wherein the limiting is performed responsive to a cylinder misfire event and prior to occurrence of a pre-ignition event in the engine. ### Claim 9 (depends on 7) The method of claim 7, wherein the threshold is a first threshold, the method further comprising, in response to a pre-ignition event in the engine, further limiting the intake aircharge directed into the cylinders to be less than a second threshold lower than the first threshold. ### Claim 10 (depends on 9) The method of claim 9, wherein the further limiting is discontinued after a key-on or key-off event. ### Claim 11 A method of controlling an engine for preventing pre-ignition, comprising: in response to a misfire event: shutting off fuel to a first cylinder; operating a second cylinder with an air-to-fuel ratio leaner than stoichiometry; and limiting an amount of intake air charge directed into the second cylinder to be less than a threshold, the limiting increased as a degree of leanness of the air-fuel mixture increases. ### Claim 12 (depends on 11) The method of claim 11, wherein the limiting is further based on a pre-ignition history of the engine, the limiting increased as a pre-ignition count of the engine increases relative to a threshold count, the method further comprising, in response to an indication of knock, using spark retard and EGR to address the knock, and in response to an indication of pre-ignition, using cylinder enrichment or cylinder enleanment to address the pre-ignition. ### Claim 13 (depends on 12) The method of claim 12, wherein the limiting is discontinued after a threshold duration has elapsed. ### Claim 14 A method of controlling an engine for preventing pre-ignition comprising: operating the engine in a first mode with all cylinders combusting at stoichiometry and with intake airflow adjusted to limit engine load to a first load limit; operating the engine in a second mode with a first number of cylinders pumping air without injected fuel, a second number of cylinders operating at an air-fuel ratio leaner than stoichiometry, and with intake airflow adjusted to limit engine load to a second load limit more restrictive than the first load limit at higher engine speeds, the first and second load limits based at least on engine speed; and operating the engine in a third mode with all cylinders combusting and at least one cylinder operating at an air-fuel ratio richer than stoichiometry, and with intake airflow adjusted to limit engine load to a third load limit more restrictive than the second load limit at lower engine speeds. ### Claim 15 (depends on 14) The method of claim 14, wherein during the third mode of operation, the third load limit is reset in response to an engine on/off cycle, wherein during the first mode of operation, the first load limit is reset upon elapse of a first threshold duration, and wherein during the second mode of operation, the second load limit is reset upon elapse of a second threshold duration. ### Claim 16 (depends on 15) The method of claim 15, wherein the first threshold duration is based on an engine pre-ignition count, and wherein the second threshold duration is based on an engine pre-ignition count and an exhaust temperature. ### Claim 17 (depends on 16) The method of claim 16, further comprising, indicating a cylinder pre-ignition event based on a knock sensor output estimated in a first, earlier crank angle window being larger than a first, higher threshold while indicating a cylinder knock event based on the knock sensor output estimated in a second, later crank angle window being larger than a second, lower threshold. ### Claim 18 (depends on 17) The method of claim 17, further comprising, addressing the cylinder knock event using spark retard and EGR while addressing the cylinder pre-ignition with one of cylinder enrichment or enleanment. ### Claim 19 (depends on 18) The method of claim 18, further comprising: operating in the first mode before an indication of a cylinder misfire event or a cylinder pre-ignition event is received; transitioning to the second mode in response to the cylinder misfire event; and transitioning to the third mode in response to the cylinder pre-ignition event.