Method of controlling fuel injection amount of internal combustion engine

A method of controlling a fuel injection amount of an internal combustion engine using a control device, the method comprising:

• a target injection amount calculation step at which a target injection amount to be injected from an injector is calculated according to an operating condition of the internal combustion engine;
• a component-by-component wear amount estimation step at which a component-by-component wear amount of an injector component is estimated, the component-by-component wear amount being a wear amount of the injector component, the injector component being a plurality of members or a part of the member constituting the injector and selected in advance as the injector component affects an accuracy of the fuel injection amount from the injector;
• a component-by-component correction amount calculation step at which a component-by-component correction amount for the injector component is calculated based on the component-by-component wear amount of the injector component, the component-by-component correction amount for the injector component being a correction amount for the injector component;
• a total correction amount calculation step at which a total correction amount is calculated based on the component-by-component correction amount of the injector component, the total correction amount is a total correction amount for the entire injector;
• and
• a total correction amount reflection step at which the injector injects a corrected target injection amount, the corrected target injection amount being the target injection amount corrected by the total correction amount.