| 摘要 |
PROBLEM TO BE SOLVED: To prevent excessive correction of a fuel injection quantity and further improve the accuracy of an air-fuel ratio control.SOLUTION: An internal combustion engine control unit for exerting a feedback control over an air-fuel ratio while referring to an output signal from an air-fuel sensor provided upstream of an exhaust gas purification catalyst, compares the output signal with a target value corresponding to a target air-fuel ratio, determines whether a current air-fuel ratio is leaner or richer than the target air-fuel ratio in response to a magnitude relation obtained by comparison, corrects a fuel injection quantity to be increased if determining that the current air-fuel ratio is leaner than the target air-fuel ratio, and corrects the fuel injection quantity to be decreased if determining that the current air-fuel ratio is richer than the target air-fuel ratio. Furthermore, the control unit adjusts an increment of the fuel injection quantity corrected to be increased or a decrement of the fuel injection quantity corrected to be decreased in response to a lapsed period between time at which a determination result is switched from rich to lean or from lean to rich and time that is closest to the former time and at which the determination result is switched from the lean to rich or from rich to lean. |
