Patent ID: 6513320
Filing Date: 2003-02-04
Classification: F01N,F02D,Y02T

Abstract:
An engine 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 and an exhaust system having a lean NOx conversion catalyst for lowering an emission level of nitrogen oxides (NOx) in exhaust gas at an air-fuel ratio of &lgr;>1 for controlling the engine to operate with a fuel charge of &lgr;>1 in a zone of partial engine loadings, said engine control system comprising:engine operating condition monitoring means for monitoring engine operating conditions; and fuel injection control means for, while said engine operating condition monitoring means monitors engine operating conditions in said partial engine loading zone, dividing a given amount of fuel into two parts which are intermittently delivered through early and late split injection, respectively, in a intake stroke, and controlling said fuel injector such that a midpoint between points at which said early and late split injection are timed respectively to start, respectively, is before a midpoint of a intake stroke.