Patent ID: 7054734

Claim:
A combustion control system of an internal combustion engine employing an exhaust purifying device in an exhaust passage, comprising: sensors that detect operating conditions of the engine; a control unit being configured to be electronically connected to the sensors, for combustion control and fail-safe purposes; the control unit comprising a processor programmed to perform the following, (a) estimating an operating condition of the exhaust purifying device; (b) determining, based on the operating condition of the exhaust purifying device, whether a request for a rise in an exhaust temperature is present; (c) executing, by way of fuel injection control in presence of the request for the exhaust temperature rise, a split retard combustion mode in which a main combustion needed to produce a main engine torque and at least one preliminary combustion occurring prior to the main combustion are both achieved and additionally the preliminary combustion takes place near top dead center on a compression stroke and additionally the main combustion initiates after the preliminary combustion has been completed; (d) predicting a temperature of the exhaust purifying device to determine a predicted temperature value; and (e) executing a fail-safe process according to which an injection timing of main fuel injection for the main combustion is compensated for in a timing-advance direction, when the predicted temperature value exceeds a predetermined temperature threshold value.