CONTROL METHOD AND CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

An internal combustion engine () includes: an exhaust gas recirculation unit equipped with an exhaust gas recirculation control valve (); a crank angle sensor () that detects an indicated mean effective pressure fluctuation rate (cPi) as an indicator of combustion stability of the internal combustion engine (); and a controller () that corrects the EGR rate of the exhaust gas recirculation unit based on the combustion stability. The controller () is configured to: increase-correct the EGR rate by a predetermined amount when the state where the indicated mean effective pressure fluctuation rate (cPi) is lower than a threshold value continues for a predetermined number of cycles; and decrease-correct the EGR rate by a predetermined amount immediately when the indicated mean effective pressure fluctuation rate (cPi) is higher than or equal to the threshold value.