Control method and control device for internal combustion engine

A control device for an internal combustion engine, comprising:

• an exhaust gas recirculation unit equipped with an exhaust gas recirculation control valve;
• at least one sensor that detects a rotation fluctuation or in-cylinder pressure associated with combustion stability of the internal combustion engine;
• and
• a controller that corrects an exhaust gas recirculation rate of the exhaust gas recirculation unit based on the combustion stability,
• wherein the controller is configured to:
• when the combustion stability satisfies a predetermined level, increase-correct the exhaust gas recirculation rate by a predetermined amount at every lapse of a predetermined cycle number;
• and
• decrease-correct the exhaust gas recirculation rate immediately when the combustion stability is detected as being lower than the predetermined level;
• and
• wherein the controller is further configured to, during a time at which the internal combustion engine remains at a certain operation point, prohibit the increase correction of the exhaust gas recirculation rate based on the combustion stability from being performed at the certain operation point when the decrease correction of the exhaust gas recirculation rate based on the combustion stability has been performed.