| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an air-fuel ratio control device for an internal combustion engine capable of adequately controlling an air-fuel ratio during the reduced cylinder operation of the internal combustion engine. <P>SOLUTION: When an internal combustion engine is operated in a reduced cylinder operation mode (Yes in Step 1005), the number of cutoff cylinders is checked in Step 1010. Then, the increase in the exhaust pressure corresponding to the checked cutoff cylinder number and the detected intake air flow rate are calculated in Step 1015, and the enhancement quantity of the responsiveness of a downstream side air-fuel side ratio sensor corresponding to the increase in the exhaust pressure is calculated in Step 1020. The reduction in the detection time of the downstream side air-fuel ratio sensor corresponding to the enhancement quantity of the calculated responsiveness is calculated in Step 1025. By considering the enhancement of the responsiveness of the air-fuel ratio sensor during the reduced cylinder operation of the internal combustion engine, the responsiveness of the feedback control is improved, and the air-fuel ratio is adequately controlled. <P>COPYRIGHT: (C)2012,JPO&INPIT |
