Control system and method for internal combustion engine

Abstract

There is provided a control system for an internal combustion engine, which is capable of matching an output torque of the engine with a demanded torque excellently when the combustion mode is switched, thereby enhancing drivability. A demanded fuel amount and a demanded torque of the engine are calculated according to detected operating conditions of the engine. A combustion mode is determined to be either the stratified combustion mode or the homogeneous combustion mode according to the demanded torque. A pre-switching demanded fuel injection time period and a pre-switching demanded torque are stored. When the combustion mode is switched, a switching-time demanded fuel amount (limit value) is calculated according to the stored pre-switching demanded fuel injection time period and pre-switching demanded torque, the current demanded torque, and an estimated combustion efficiency parameter.