Exhaust purification apparatus and method for internal combustion engine

In exhaust purification apparatus and method for an internal combustion engine having an exhaust gas purification catalyst disposed in an exhaust passage of the engine, a poisoning release control of the exhaust gas purification catalyst is executed when a predetermined condition is established, the poisoning release control including a normal mode and an exhaust gas composition mode before the normal mode, and a manipulation parameter (for example, an ignition timing) of the engine related to an exhaust gas composition is manipulated in such a manner that a hydrogen concentration in the exhaust gas in the exhaust gas composition mode is higher than that in the normal mode.