Method for controlling internal combustion engine and device for controlling internal combustion engine

A control device for controlling an internal combustion engine, the control device comprising:

• an electric motor configured to rotate a crankshaft to start the internal combustion engine;
• an air amount adjustment part configured to adjust an amount of air supplied into cylinders;
• a first control part configured to stop fuel injection to automatically stop the internal combustion engine when predetermined automatic stop conditions are met;
• and
• a second control part configured to start the internal combustion engine in response a request to restart the internal combustion engine while an engine speed of the internal combustion engine is decreasing due to an automatic stoppage by resuming fuel injection when the engine speed of the internal combustion engine is equal to or greater than a predetermined rotational speed threshold at which restarting is possible only by fuel injection, and by using the electric motor when the engine speed of the internal combustion engine is lower than the rotational speed threshold,
• the second control part being configured to control the air amount adjustment part when the engine speed of the internal combustion engine falls below the rotational speed threshold while the engine speed is decreasing due to an automatic stoppage so that the amount of air entering the cylinders is less than before the engine speed fell below the rotational speed threshold.