Cylinder injection type internal combustion engine

A method of maintaining activation of an exhaust gas purifying catalyst device provided in an exhaust passage of an in-cylinder injection type internal combustion engine having fuel injection valves for injecting fuel directly into combustion chambers of the engine, comprising:

• detecting cold start of the engine;
• executing a multi-stage injection mode, which includes main fuel injection for main combustion and additional fuel injection in an expansion stroke after said main injection, to preheat the temperature of said exhaust gas purifying catalyst device after cold start is detected;
• executing a reduced fuel consumption temperature increasing mode, which achieves stratified fuel combustion in such a manner that an air-fuel ratio of the engine becomes stoichiometric or in a vicinity thereof, to further increase temperature of said exhaust-gas purifying catalyst device;
• and
• executing said multi-stage injection mode and then said reduced fuel consumption temperature increasing mode.

An in-cylinder injection type internal combustion engine having fuel injection valves for injecting fuel directly into combustion chambers of said internal combustion engine, comprising:

• ignition plugs provided on an engine body in such a way as to face said combustion chambers;
• an exhaust-gas purifying catalyst device, provided in an exhaust passage of the internal combustion engine, arranged to purify harmful components in an exhaust gas;
• and
• a control device having a temperature-increase control section arranged to achieve stratified combustion in such a way that an air-fuel ratio of said internal combustion engine becomes a stoichiometric air-fuel ratio or in a vicinity thereof when an increase in a temperature of said exhaust-gas purifying catalyst device is needed,
• wherein said control device further includes an additional-fuel injection control section for injecting fuel in an injection other than a main injection for main combustion,
• wherein before activation of said temperature-increase control section, said control device causes said additional-fuel injection control section to inject additional fuel in an expansion stroke after said main injection,
• wherein said control device further includes an injection-timing control section arranged to control injection timings of said fuel injection valves and ignition-timing control section for controlling ignition timings of said ignition plugs, and
• wherein at a time said temperature-increase control section is activated, said control device adjusts at least one of said injection timings set by said injection-timing control section and said ignition timings set by said ignition-timing control section in such a way as to make an interval between injection timing and ignition timing longer than in the stratified combustion in which said temperature-increase control section is not activated.