Patent ID: 6178944
Filing Date: 2001-01-30
Classification: F02B,Y02T

Abstract:
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; andin 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.