Exhaust gas purification apparatus

An exhaust gas purification apparatus for an internal combustion engine including an exhaust passage, the exhaust gas purification apparatus comprising:

• a catalyst device arranged in the exhaust passage, the catalyst device configured to purify exhaust gas of the internal combustion engine;
• an exhaust ignition device arranged in the exhaust passage upstream from the catalyst device, the exhaust ignition device configured to ignite an air-fuel mixture in the exhaust passage;
• and
• a controller configured to control a catalyst heating treatment of the catalyst device by adjusting (i) a supply of the air-fuel mixture to the exhaust ignition device, and (ii) an ignition of the air-fuel mixture via the exhaust ignition device, the catalyst heating treatment including:
• setting a target value of an equivalence ratio of the air-fuel mixture to a first equivalence ratio greater than 1 until a predetermined first time elapses from a start of the supply of the air-fuel mixture, and
• setting the target value to a second equivalence ratio less than 1 when the first time elapses.