Patent ID: 6266957
Filing Date: 2001-07-31
Classification: F01L,F02D,F02M,F02P,Y02T

Abstract:
A catalyst activation control system for a spark ignition type internal combustion engine, said system comprising:a catalyst converter provided in an engine exhaust pipe;exhaust gas temperature control means for setting exhaust gas temperature at desirable temperature when an exhaust valve is opened by controlling burning velocity of air-fuel mixture within a cylinder when the engine is cold; andtorque fluctuation suppressing means for suppressing fluctuation of torque in controlling the burning velocity;wherein the exhaust gas temperature control means controls when the engine is cold, ignition timing to a more retarded angle side than that after engine warm up;wherein the exhaust gas temperature control means also controls an air-fuel ratio of intake fuel and air mixture to a stoichiometric ratio or slightly lean when the engine is cold,an air-fuel ratio sensor for detecting an actual air-fuel ratio to implement open-loop control on the control target value of the air-fuel ratio at least before the air-fuel ratio sensor becomes active;storage means for storing a correction value calculated corresponding to a deviation between the actual air-fuel ratio and the control target value right after when the air-fuel ratio sensor is activated in a backup memory at any time in controlling the air-fuel ratio by the exhaust gas temperature control means; andcorrecting means for correcting a fuel injection amount by reading the correction value from the backup memory during the open-loop control before the sensor is activated in controlling the air-fuel ratio by the exhaust gas temperature control means.