Fuel injection method for an internal combustion engine

摘要

A fuel injection method and strategy for an internal combustion engine wherein the fuel injection event that occurs during each combustion cycle of a four-cycle internal combustion engine. A first fuel injection event may occur during the intake stroke of the combustion cycle, thereby creating a lean homogeneous air/fuel mixture. A second fuel injection event may occur during the compression stroke. The combustion gases created in the combustion chamber of the engine are transferred to an exhaust system during the exhaust stroke. The injected fuel mixes with the air present in the combustion chamber to create a lean air/fuel mixture. The valve timing for the engine is deliberately adjusted to a setting that is less than the maximum torque setting where hydrocarbon production occurs during the combustion event. The exhaust gas hydrocarbon content for any given ignition spark timing increases as the injection timing before top dead center is increased.