DIRECT-INJECTION SPARK IGNITION ENGINE

摘要

During stratified-charge combustion operation of a direct-injection spark ignition engine (1), at the compression stroke of a cylinder (2), a tumble T is generated which flows between a spark plug (16) electrode and a piston (5) crown surface toward an injector (18). A fuel is injected from the injector (18) in correspondence with the ignition timing for the cylinder (2) by controlling the penetration of fuel spray from the injector (18) to correspond to the flow rate of the tumble T so that the fuel spray goes against the tumble T, becomes a flammable mixture at the ignition timing for the cylinder (2) and stays in the vicinity of the spark plug (16) electrode. In the late stage of the compression stroke of the cylinder (2), diffusion of the flammable mixture is suppressed with squishes. In this manner, fuel spray behavior in the combustion chamber (6) is controlled to allow suitable mixture stratification over a wide range of operating conditions of the engine (1).