| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent degradation of emission by detecting excessive air-fuel ratio unevenness between cylinders, and to take measures to meet such the situation. <P>SOLUTION: A fuel injection amount control device (control device) performs the feedback correction of the amount of the fuel to be injected from a fuel injection valve 33 based on the output value of an upstream side air-fuel ratio sensor 56 so that the air-fuel ratio of exhaust gas flowing into a three-element catalyst 43 is coincident with the target value. The control device 70 acquires the air-fuel ratio imbalance index value which is increased more as the degree of unevenness of the air-fuel ratio between cylinders is increased on the basis of the output value of the upstream side air-fuel ratio sensor, calculates an imbalance rich correction amount based on the air-fuel ratio imbalance index value, and corrects the air-fuel ratio of the engine to the rich side by the imbalance rich correction amount. However, during the predetermined period after starting the engine, since the air-fuel ratio of the engine is corrected to the rich side by the start correction amount, the control device performs reduction correction of the imbalance rich correction amount. <P>COPYRIGHT: (C)2012,JPO&INPIT |
