AIR-FUEL RATIO CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To suppress an actual air-fuel ratio of an entire engine from being excessively deviated from a theoretical air-fuel ratio when imbalance occurs due to the intensity of exhaust hitting a sensor according to a cylinder causing imbalance in the air-fuel ratio between cylinders.SOLUTION: The cylinder causing the imbalance between the cylinders is detected when a deviation occurs between an output of an air-fuel ratio sensor 18 and a target value, which is a value obtained by using the actual air-fuel ratio of an internal combustion engine 1 having the same output as the theoretical air-fuel ratio, due to the imbalance in the air-fuel ratio between the cylinders in the internal combustion engine 1. Subsequently, correction corresponding to the cylinder causing the imbalance in the air-fuel ratio between the cylinders is added to a sub feedback correction value VH. Accordingly, even if the intensity of the exhaust hitting the air-fuel ratio sensor 18 is different depending on the cylinder causing the imbalance, an effect on the sub feedback correction value VH can be suppressed.