PURPOSE: To improve surge torque in a partial area by a method wherein the standard deviation of an indicated average effective pressure of each cylinder is calculated and at least one of an ignition timing, a fuel injection amount, and an air-fuel ratio is controlled classified by a cylinder so that the standard deviation of the indicated average effective pressure of each cylinder is indicated in the vicinity of a stability limit in a partial area.
CONSTITUTION: During operation of a vehicle, output signals from an O2 sensor 3, a crank angle sensor 4, an airflow meter 6, and a water temperature sensor 11 are inputted to a control unit 2 and an air-fuel ratio (a fuel injection amount) and an ignition timing are respectively controlled. In this case, the standard deviation of the indicated average effective pressure of each cylinder is calculated and at least one of an ignition timing, a combustion injection amount, and an air-fuel ratio is controlled classified by a cylinder so that the obtained standard deviation is indicated in the vicinity of a stability limit in a partial area. For example, an ignition timing correction amount of each cylinder is calculated so that the standard deviation of the indicated average effective pressure of each cylinder is indicated in the vicinity of the stability limit in the partial area and a fundamental ignition timing is corrected by an ignition timing correction amount is corrected to determine a final ignition timing.
KAKIZAKI SHIGEAKI
TSUCHIDA HIROBUMI
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