Direct fuel injection/spark ignition engine control device

A direct fuel injection/spark ignition engine control device comprising:

• environment condition determination means for determining a low intake air density condition that is adverse to stratified combustion by compression stroke injection;
• catalyst condition determination means for determining a state of a catalyst for exhaust purification disposed in an exhaust passage of an engine;
• and
• combustion control means for controlling a combustion mode such that a stratified combustion mode is performed with a compression stroke injection from the time of startup when warming up of the catalyst is determined, and such that the stratified combustion with the compression stroke injection is prevented and a combustion mode with an intake stroke injection is performed when warming up of the catalyst is determined under conditions of low air density.

A method of controlling combustion in a direct fuel injection/spark ignition engine comprising:

• determining a low intake air density condition that is adverse to stratified combustion by compression stroke injection;
• determining a state of a catalyst for exhaust purification disposed in an exhaust passage of an engine;
• and
• controlling a combustion mode such that a stratified combustion mode is performed with a compression stroke injection from a time of startup when warming up of the catalyst is determined, and such that the stratified combustion mode with the compression stroke injection is prevented and a combustion mode with an intake stroke injection is performed when warming up of the catalyst is determined under conditions of low air density.