DIRECT INJECTION SPARK IGNITION ENGINE

摘要

A spark ignition internal combustion engine is described having a variable volume combustion chamber (10) defined by a cylinder head (12), a cylinder bore (14) and a piston (16) reciprocating within the cylinder bore (14). The cylinder head (12) has a spark plug (40) and intake and exhaust ports (20, 30) leading through intake and exhaust valves (26, 36) into the combustion chamber (10). A fuel injector (50) is provided for injecting liquid fuel directly into the combustion chamber (10) to produce a powerful ignition kernel for igniting a homogeneous premixed charge in the combustion chamber (10). The fuel injector (50) is positioned in an unswept part of the cylinder bore (14) and oriented to spray fuel obliquely towards the front face of the intake valve (26) in the direction of the spark plug (40). An engine management system (60) generates a spark at the spark plug electrodes at a predetermined spark timing in the engine cycle, and operates the injector (50) in a predetermined prior phase relationship with the spark timing to direct towards the vicinity of the spark plug gap (42) a small quantity of fuel only sufficient to generate at the time of ingition a localised region of readily ignitable mixture having its centre in the immediate vicinity of the spark gap (42). The resulting ignition of the localised ignitable region by the spark and the combustion thereof produces a powerful ignition kernel for igniting the premixed charge in the combustion chamber (10).