Exhaust gas purification apparatus for internal combustion engine

An exhaust gas purification apparatus for an internal combustion engine comprising:

• an electrically heated catalyst arranged in an exhaust passage of an internal combustion engine and including a heat generation element that generates heat by being energized and an exhaust gas purification catalyst;
• and
• a controller including at least one processor,
• wherein the controller is configured to:
• start electrical energization of the electrically heated catalyst before starting of the internal combustion engine;
• obtain an electric resistance value of the electrically heated catalyst after the lapse of a predetermined period of time which is a period of time required for condensed water adhered to the electrically heated catalyst to finish evaporating from the start of energization of the electrically heated catalyst by the controller;
• calculate a heat energy shortage amount which is an amount of heat energy insufficient for raising the temperature of the electrically heated catalyst to a predetermined temperature or above, based on a resistance difference which is a difference between the electric resistance value obtained by the controller and a predetermined reference resistance value;
• and
• supply to the electrically heated catalyst an amount of energy required to compensate for the heat energy shortage amount calculated by the controller.