| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal combustion engine control unit capable of suppressing the degradation of exhaust gas purification performance when there occurs irregularity among cylinders even.SOLUTION: A control unit 30 implements an air-fuel ratio control by main feedback correction using an output value from an upstream sensor 35 in response to an actual air-fuel ratio on upstream of a catalyst 100 and sub-feedback correction using an output value from a downstream sensor 36 in response to an actual air-fuel ratio on downstream of the catalyst 100. A sub-correction value of the sub-feedback correction includes a sub-learned value for compensating for a stationary deviation between the output value from the downstream sensor 36 and an output value corresponding to a target air-fuel ratio. A control unit 30 corrects a fuel injection quantity corrected by the air-fuel ratio control if there is irregularity of the fuel injection quantity of a fuel injection valve among cylinders. Furthermore, the control unit 30 stores, as a normal value, the sub-learned value whenever it is determined that the degree of irregularity among the cylinders is not higher than a predetermined value, and changes the sub-learned value to the stored normal value when it is determined that the degree of irregularity among the cylinders is not lower than the predetermined value.SELECTED DRAWING: Figure 1 |
