To smoothen switch between combustion modes, and thereby to solve a problem of degradation of emission in the switch between the modes.
An engine 10 is constituted of a cylinder injection internal combustion engine. Operation of the engine is switchable between an uniform combustion operation where fuel is injected in an intake stroke to perform uniform combustion of the fuel, and a stratified charge combustion operation where the fuel is injected in a compression stroke to perform stratified charge combustion of the fuel. An ECU 50 performs a throttle control to match an intake air amount with air amount requirement, and uses throttle learning values appropriately for the combustion mode. The throttle learning values are individually set for combustion modes of the uniform combustion and stratified charge combustion. The ECU 50 determines whether or not the switch between combustion modes is required, based on an operational status. When determining that the switch between combustion is required, the ECU reflects the throttle learning value appropriate for the next mode, before actually switching between the combustion modes. The combustion modes are switched after the reflection of the throttle leaning value.
Daito Kato
Takashi Ito