Combustion control apparatus for internal combustion engine

摘要

An engine includes a variable valve timing mechanism (VVT 80) to adjust the valve overlap of intake valves (18) and exhaust valves (20) in accordance with the running state of the engine. The engine operates either in stratified charge combustion mode or in homogenous charge combustion mode in accordance with the running state of the engine. When, for example, the VVT (80) cannot operate normally due to lack of hydraulic pressure, an ECU (44) judges that the state of the VVT (80) is not suitable for stratified combustion and forces the engine to operate in the homogenous combustion mode regardless of the running state of the engine. As a result, the combustion state of the engine does not deteriorated and the amount of NOx in the exhaust gas does not increase. <IMAGE>