Patent ID: 6237327
Filing Date: 2001-05-29
Classification: F01N,F02D,F02P,Y02T

Abstract:
A fuel combustion control system for an internal combustion engine for controlling ignition timing and air/fuel ratio so as to cause a rise in exhaust gas temperature while an exhaust gas purifying catalyst installed in an exhaust line of the engine is insufficiently warmed, said fuel combustion control system comprising:speed monitoring means for monitoring an engine speed;temperature monitoring means for monitoring engine cooling water temperature, andcontrol means for detecting a degree of fluctuations of said engine speed, determining on the basis of said temperature whether said engine is still in a cold condition, controlling said ignition timing to a retarded condition so as to cause a rise in exhaust gas temperature while said engine is in said cold condition and to advance from said retarded ignition timing by a timing degree which is necessary to cause a rise in catalyst temperature but less than a predetermined timing degree while said degree of fluctuations is greater than a predetermined value, and controlling an air/fuel ratio to gain a value on an lean side of stoichiometric value represented by an air excess ratio (.lambda.=1) while said engine is in said cold condition and to turn back said value of air/fuel ratio toward a rich side of said stoichiometric value when said ignition timing is advanced by said predetermined timing degree.