Control apparatus and control method for direct injection spark ignition internal combustion engine

Abstract

An ECU controls an internal combustion engine that creates a tumble flow in each engine cylinder and intensifies the tumble flow using fuel injected at a timing near the intake stroke bottom dead center during homogeneous combustion. The ECU includes a fuel property identifying mechanism identifying the property of fuel and combustion state changing mechanism changing the combustion state. When the fuel has a property that requires a stoichiometric air-fuel ratio lower than the stoichiometric air-fuel ratio for gasoline, the combustion state changing mechanism changes the combustion state by, for example, retarding the ignition timing, so that the combustion progresses moderately. This prevents an excessive increase in the combustion speed.