Combustion changeover control for engine

摘要

An engine control system for an internal combustion engine comprises a combustion system for changing over a combustion mode from a first mode such as a stratified charge combustion mode to a second mode such as a homogeneous charge combustion mode, and an EGR system for controlling an EGR flow to the engine with an EGR control valve. A controller calculates a delayed target equivalent ratio which varies gradually from a first ratio for the first mode to a second ratio for the second mode, and further calculates a modified target equivalent ratio in consideration of an amount of an EGR gas. The controller determines the combustion changeover timing by monitoring a parameter based on the modified target equivalent ratio to take account of the influence of the EGR gas.