Patent ID: 6857414

Claim:
A control system for an internal combustion engine of an in-cylinder injection type, which causes the engine to operate while switching a combustion mode thereof between a stratified combustion mode in which stratified combustion of a mixture is carried out and a homogeneous combustion mode in which homogenous combustion of the mixture is carried out, and at the same time controls a fuel injection amount based on a demanded fuel amount which is calculated, the control system comprising: operating condition-detecting means for detecting operating conditions of the engine; demanded fuel amount-calculating means for calculating the demanded fuel amount according to the detected operating conditions of the engine; demanded torque-calculating means for calculating a demanded torque of the engine according to the detected operating conditions of the engine; combustion mode-determining means for determining which of the stratified combustion mode and the homogeneous combustion mode should be selected as the combustion mode, according to the calculated demanded torque; storage means for storing the demanded fuel amount and the demanded torque both calculated immediately before the combustion mode has been switched according to the determination by said combustion mode-determining means; combustion efficiency-estimating means for estimating combustion efficiency of the engine; and switching-time demanded fuel amount-calculating means responsive to switching of the combustion mode, for calculating a switching-time demanded fuel amount, as the demanded fuel amount, according to the stored demanded fuel amount and demanded torque, the demanded torque currently calculated by said demanded torque-calculating means, and the combustion efficiency currently estimated by said combustion efficiency-estimating means.