Patent ID: 6116208
Filing Date: 2000-09-12
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, an intake system 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 .lambda.>1 for controlling the engine to operate with a fuel charge of .lambda.>1 in a zone of partial engine loadings and with a fuel charge of .lambda.<1 in an enriched charge zone other than said partial engine loading zone, said engine control system comprising:engine operating condition monitoring means for monitoring engine operating conditions;exhaust gas recirculation means for recirculating exhaust gas partly into said intake system from said exhaust system; andfuel injection control means for, while said engine operating condition monitoring means monitors engine operating conditions in said enriched charge zone, dividing a given amount of fuel into at least two parts which are delivered intermittently through early and late split injection in an intake stroke of said cylinder piston respectively and causing said exhaust gas recirculation means to recirculate exhaust gas into an intake air stream introduced into said intake system from said exhaust system while said fuel injector executes said early and late split injection.