EXHAUST GAS PURIFICATION APPARATUS FOR AN INTERNAL COMBUSTION ENGINE

In an exhaust gas purification apparatus for an internal combustion engine, the apparatus comprising NOx storage reduction catalyst, and a controller comprising at least one processor is configured to carry out rich spike, wherein in cases where the storage amount of NOx is the same, in a period of time from the completion of the execution of the last rich spike to the start of the execution of the current rich spike, the controller makes a period of execution of the current rich spike longer, and/or a degree of richness of a rich air fuel ratio achieved by the execution of the current rich spike larger, in the case where a period of time in which a temperature of the NOx storage reduction catalyst becomes equal to or higher than a predetermined determination temperature is long than in the case where it is short.