Patent ID: 6401703
Filing Date: 2002-06-11
Classification: F02D

Abstract:
A fuel control system for a direct-injection spark-ignition type of engine which is equipped with a fuel injector for spraying fuel directly into a combustion chamber in a compression stroke so as to cause stratified charge combustion in a specified engine operating region of lower engine loads and lower engine speeds, said fuel injection control system comprising:speed detection means for detecting a speed of rotation of said engine; air-fuel ratio detection means for detecting as an air-fuel ratio representative of an actual quantity of fuel injection by said fuel injector; intake air quantity regulation means for regulating a quantity of intake air that is admitted into said combustion chamber; control means for calculating a target quantity of fuel injection on the basis of at least said engine speed learning a quantitative variation between said actual quantity of fuel injection and said target quantity of fuel injection when the engine is idling in said specified engine operating region, for controlling said intake air regulation means so as to provide a constant quantity of intake air that is admitted into said combustion chamber while learning said quantitative variation, and for performing feedback control of said actual quantity of fuel injection so as to bring said engine speed into a specified idling engine speed while learning said quantitative variation; wherein said quantitative variation is learned on the basis of feedback control values in said feedback control for a plurality of specified fuel injection timings which take place in turn.