Valve cleaning method for direct injection spark ignition engine
AssigneeFord Global Technologies, LLC
InventorsJames Michael Kerns, Michael John Cullen
Life of this patent
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Abstract
A control method and system is described for a spark ignited, four-stroke engine having multiple combustion chambers, each coupled to at least one intake and one exhaust valve, a fuel injection system for injecting fuel directly into each combustion chamber, and an electronically controlled throttle for throttling air inducted through an intake manifold into the combustion chambers. Additional fuel is injected during the exhaust valve overlap. This additional fuel is drawn from the combustion chamber into the intake manifold and subsequently inducted back into the combustion chamber past the intake valve, thereby cleaning carbon deposits from the intake valve and the surrounding surfaces.
Claims16
A control method for a spark ignited four-stroke engine having multiple combustion chambers, each coupled to at least one intake and one exhaust valve, a fuel injection system for injecting fuel directly into each combustion chamber, and an electronically controlled throttle for throttling air inducted through an intake manifold into the combustion chambers, comprising:
- detecting when to initiate an intake valve cleaning;
- indicating when the engine is operating in a homogeneous mode wherein the throttle is partially closed and fuel is injected during an engine intake stroke to generate a homogeneous air/fuel mixture;
- and
- in response to said valve cleaning detection and said homogeneous mode indication, injecting additional fuel during a valve overlap of the intake and exhaust valves so that fuel is drawn into the intake manifold and subsequently inducted back into the combustion chamber past the intake valve.
A control method for a spark ignited four-stroke engine having multiple combustion chambers, each coupled to at least one intake and one exhaust valve, a fuel injection system for injecting fuel directly into each combustion chamber, and an electronically controlled throttle for throttling air inducted through an intake manifold into the combustion chambers, comprising:
- detecting when to initiate an intake valve cleaning;
- indicating when the engine is operating in a homogeneous mode wherein the throttle is partially closed and a predetermined amount of fuel is injected during an engine intake stroke to generate a homogeneous air/fuel mixture;
- in response to said valve cleaning detection and said homogeneous mode indication, injecting additional fuel during a valve overlap of the intake and exhaust valves so that fuel is drawn into the intake manifold and subsequently inducted back into the combustion chamber past the intake valve to clean valve deposits;
- and
- reducing said predetermined amount of fuel injected during the intake stroke by an amount proportional to said additional fuel injected during said valve overlap.
A control system for a spark ignited four-stroke engine having multiple combustion chambers each coupled to at least one intake and one exhaust valve, comprising:
- a fuel injection system for injecting fuel directly into each combustion chamber;
- an electronically controlled throttle for throttling air inducted through an intake manifold into the combustion chambers;
- said control system operating the engine in a homogeneous mode by partially closing the throttle and injecting a predetermined amount of fuel during an engine intake stroke to generate a homogeneous air/fuel mixture;
- said control system detecting when to initiate an intake valve cleaning;
- and
- in response to said valve cleaning detection and while operating in said homogeneous mode, said control system injecting additional fuel during a valve overlap of the intake and exhaust valves so that fuel is drawn into the intake manifold and subsequently inducted back into the combustion chamber past the intake valve to clean valve deposits.
Dependencies are inferred from the claim text.