Patent ID: 6058905
Filing Date: 2000-05-09
Classification: F02D,Y02T

Abstract:
A fuel injection control system for a cylinder direct injection spark-ignition internal combustion engine, comprising:a section for regulating fuel to be injected into a cylinder of the engine so that first and second quantities of fuel are injected respectively on intake and compression strokes in each cycle of the cylinder under a predetermined engine operating condition, said first and second quantities corresponding respectively to first and second allocation rates of fuel;a section for setting said first and second allocation rates in accordance with air-fuel ratio of air-fuel mixture to be formed in the cylinder;a section for judging a homogeneous charge combustion condition which requires homogeneous charge combustion and a stratified charge combustion condition which requires stratified charge combustion, in accordance with an engine operating condition, fuel being supplied on intake stroke so as to form a rich equivalence ratio in the homogeneous charge combustion, fuel being supplied on compression stroke so as to form a lean equivalence ratio in the stratified charge combustion, the rich equivalence ratio being richer in fuel than the lean equivalence ratio; anda section for gradually changing over an equivalence ratio within a range between the rich and lean equivalence ratios when engine operation is changed over between the homogeneous charge combustion condition and the stratified charge combustion condition;wherein said fuel regulating section is arranged such that the first and second quantities of fuel are injected respectively on intake and compression at least at a predetermined time during a time period in which the equivalence ratio is gradually changed over.