To provide an air-fuel ratio control device of an internal combustion engine, in which at the resumption of air-fuel ratio feedback control, the initial value of an integral term of the feedback control can be set to a value properly learned in preceding feedback control, thereby enabling improvement of accuracy of control of air-fuel ratio.
The air-fuel ratio control device calculates target air-fuel ratio KCMD including an adaptation rule input UADP in order to perform feedback control so that O2 output value SVO2 of an O2 sensor 21 provided in the middle of catalyst 8 or in the downstream side becomes to the target value SVO2CMD. During the feedback control, when it is determined that a predetermined condition, in which it is estimated that exhaust gas air-fuel ratio of upstream side of the catalyst 8 is excellently reflected on an exhaust gas air-fuel ratio at a location midway or downstream of the catalyst, is satisfied (steps 82-84), the adaptation rule input UADP calculated immediately before interruption of the feedback control is updated and stored as the initial value UADPWINI of an integral term for the following execution of the feedback control(step 29).
MAEDA KENICHI
MIYAUCHI ATSUHIRO
WATANABE SEIJI
GOTO SOICHIRO
| JP2003214228A | 2003-07-30 | |||
| JP2008075495A | 2008-04-03 | |||
| JP2003214146A | 2003-07-30 |
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