# US 7,607,410 B2 · System and method of controlling fuel delivery during positive valve overlap operation of an engine start > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,410 B2 - Document ID: US7607410B2 - Status: Granted - Kind: B2 - Application number: 11/423,682 - Filed: 2006-06-12 - Published: 2007-12-13 - Granted: 2009-10-27 - Earliest claimed: 2006-06-12 - Assignees: Ford Global Technologies, LLC - Inventors: Steve Magner; Xiaoying Zhang; John Rollinger; Mrdjan Jankovic; Sue Wagers - Web page: https://patentgrep.com/patent/US7607410B2 ## CPC - F02D 13/0261: {Controlling the valve overlap} - F02D 41/0002: {Controlling intake air} - F02D 41/064: {at cold start (F02D41/067 takes precedence)} - F02M 26/01: Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages - F01L 1/34: characterised by the provision of means for changing the timing of the valves without changing the duration of opening {and without affecting the magnitude of the valve lift} - F01L 2001/0537: {Double overhead camshafts [DOHC]} - F01L 2800/01: Starting - F01L 2800/10: Providing exhaust gas recirculation [EGR] - F02D 13/0203: {Variable control of intake and exhaust valves} - F02D 41/047: {Taking into account fuel evaporation or wall wetting; (special correction after fuel cut-off F02D41/126)} - F02D 2013/0292: {in the start-up phase, e.g. for warming-up cold engine or catalyst} - F02M 25/089: {Layout of the fuel vapour installation} - F02M 26/13: Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An approach is provided for compensating engine fueling during starting conditions in which positive valve overlap is enabled early in the start. In one example, the valve timing is adjusted to increase positive overlap during cold starting conditions, and fuel adjustments are provided to compensate for the evaporation effects of the increased residual push-back. ## Claims ### Claim 1 A method for controlling fuel injection into an engine of a vehicle, the engine having at least a variable intake valve timing system, the method comprising: cold starting the engine with the variable valve timing system at a default position; before the engine warms to a warm-up temperature, adjusting the variable intake valve timing system to generate an increase in positive valve overlap of at least one cylinder; adjusting a fuel injection amount in response to said increase in positive valve overlap, where said adjusting the fuel injection amount provides a decrease in injected fuel to account for an increase in fuel evaporating from the intake valve and/or the intake port as engine temperature warms; and adjusting spark timing in response to said adjusting of the variable intake valve timing system and further to maintain engine idle speed. ### Claim 2 (depends on 1) The method of claim 1 where said adjustment of said fuel injection amount is based on an amount of positive valve overlap. ### Claim 3 (depends on 2) The method of claim 2 where said adjustment continues even if the positive valve overlap remains relatively fixed after said adjustment. ### Claim 4 (depends on 1) The method of claim 1 wherein the variable valve timing system is a variable cam timing system. ### Claim 5 (depends on 1) The method of claim 1 wherein the warm-up temperature is a predetermined engine coolant temperature. ### Claim 6 (depends on 1) The method of claim 1 wherein said positive valve overlap is increased by advancing intake valve timing. ### Claim 7 A method for controlling fuel injection into an engine of a vehicle, the engine having a variable valve timing system, the method comprising: starting engine with the variable valve timing system at a default position; before the engine warms to a warm-up temperature, adjusting the variable valve timing system to increase positive valve overlap of at least one cylinder; and adjusting a fuel injection amount in response to said increase in positive valve overlap, said adjustment of fuel providing a decrease in injected fuel to account for an increase in fuel evaporating from the intake valve, said fuel adjustment based on an amount of pushback residual flow due to said positive valve overlap, where said residual flow is proportional to a square of an amount of overlap between intake and exhaust valves, and then later further decreasing injected fuel to account for transient fuel evaporating from the intake port as the engine temperature warms. ### Claim 8 (depends on 7) The method of claim 7 where said adjustment of said fuel injection amount is based on an amount of positive valve overlap. ### Claim 9 (depends on 8) The method of claim 8 where said adjustment continues even if the positive valve overlap remains relatively fixed after said adjustment. ### Claim 10 (depends on 9) The method of claim 9 wherein the variable valve timing system is a variable cam timing system. ### Claim 11 (depends on 10) The method of claim 10 wherein the warm-up temperature is a predetermined engine coolant temperature. ### Claim 12 (depends on 8) The method of claim 8 wherein said fuel adjustment is based on an intake valve fuel film temperature and intake port temperature. ### Claim 13 A method for controlling fuel injection into an engine of a vehicle, the engine having a variable valve timing system, the method comprising: starting engine with the variable valve timing system at a default position and with a fuel film accumulated on an intake valve of the variable valve timing system; before the engine warms to a warm-up temperature, adjusting the variable valve timing system to increase positive valve overlap of at least one cylinder; pushing back combusted cylinder gasses past the intake valve into an intake manifold to heat the intake valve; evaporating the fuel film via said heating of the intake valve; inducting at least some evaporated fuel from the film into the cylinder; and adjusting a fuel injection amount in response to said increase in positive valve overlap, said adjustment of fuel providing a decrease in injected fuel to account for an increase in fuel evaporating from the intake valve as the engine temperature warms. ### Claim 14 (depends on 13) The method of claim 13 wherein said adjusting of the fuel injection amount is based on a fuel quality and engine speed. ### Claim 15 (depends on 14) The method of claim 14 wherein said adjusting of the fuel injection amount is further based on an intake valve fuel film temperature.