BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an internal combustion engine and a control system thereof according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of a part of the control system shown in FIG. 1;
FIG. 3 is a block diagram of a module for calculating the main injection timing (CAIM) and the target exhaust gas recirculation amount (GEGR);
FIG. 4 is a flowchart of a process for setting the switching control signal (SCTL) shown in FIG. 3;
FIG. 5 is a block diagram of the ignition timing detection block shown in FIG. 3;
FIG. 6 is a time chart showing a band pass filtering of a cylinder pressure sensor output;
FIGS. 7A-7C are time charts showing a detecting method of an ignition timing;
FIG. 8 shows a graph used for calculating a cetane number (CET) from an ignition delay time period (TDFM);
FIG. 9 is a graph showing a setting method of the determined cetane number parameter (CETD) according to the cetane number learning value (CETLRN);
FIG. 10 is a schematic diagram showing the control method in the first embodiment;
FIG. 11 is a block diagram showing a configuration of the injection timing calculation block according to a second embodiment of the present invention; and
FIG. 12 is a schematic diagram showing the control method of the second embodiment.