Catalyst activation control system for engines

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;
• and
• torque 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;
• and
• wherein the torque fluctuation suppressing means causes a plurality of times of or a plurality of locations of ignition operation per one combustion stroke.

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;
• and
• torque 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;
• and
• wherein the torque fluctuation suppressing means causes a plurality of times of ignition operation per one combustion stroke and decides at least ignition intervals or ignition number of times corresponding to combustion conditions at each moment.

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;
• and
• torque 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;
• and
• 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, the controlled air-fuel ratio being maintained while the engine is cold thereby effecting catalyst warm-up by ignition timing retardation.