Patent attributes
A control system used with an engine determines a fuel injection timing according to a detected engine operating condition and fuel injection is executed through a fuel injection valve. The target ignition timings of the fuel are set according to the detected engine operating condition and stored in a memory. An ignition delay of the actual ignition timing relative to the target ignition timing and a cetane number of the fuel are calculated. Control values of the recirculation amount of exhaust gases are set according to the detected engine operating condition and stored in the memory. The stored control value is retrieved and the recirculation amount of exhaust gases is controlled using the retrieved control value. A correction amount of the recirculation amount of exhaust gases is calculated according to the estimated cetane number and the recirculation amount of exhaust gases is controlled using the corrected control value.
