CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE AND CONTROL METHOD FOR INTERNAL COMBUSTION ENGINE

A control device for an internal combustion engine is disclosed. The internal combustion engine includes a plurality of cylinders, a fuel injection valve configured to supply fuel to each cylinder, an EGR passage configured to connect an exhaust passage and an intake passage, an EGR valve configured to adjust a flow rate of exhaust gas flowing from the exhaust passage into the intake passage through the EGR passage, and an air-fuel ratio sensor provided in the exhaust passage. The control device includes an electronic control unit configured to execute determination processing for determining that a degree of imbalance abnormality is greater when a fluctuation amount of a detection value of the air-fuel ratio sensor is relatively large than when the fluctuation amount is relatively small.