Control system for internal combustion engine

摘要

A control system for an internal combustion engine having at least one fuel injection valve for injecting fuel into a combustion chamber of the engine and burning the injected fuel by compression ignition. A fuel injection control parameter for controlling at least one fuel injection valve is changed. A combustion state of the engine is then detected. A cetane number of the fuel is then estimated based on the changed fuel injection control parameter and the detected combustion state.