EXHAUST PURIFICATION APPARATUS FOR INTERNAL COMBUSTION ENGINE

An exhaust purification apparatus for an internal combustion engine comprises a first oxidation catalyst arranged in an exhaust passage of an engine, a mixer arranged on the downstream side of the first oxidation catalyst, and a second oxidation catalyst arranged on the downstream side of the mixer. A repetitive control is carried out in such a way that a period in which an air-fuel ratio of exhaust gas discharged from an engine body is rich and a period in which the air-fuel ratio is lean are alternately repeated when the temperature of the second oxidation catalyst is to be increased, so that a part of the unburnt fuel contained in a rich exhaust gas discharged from the engine body and a lean exhaust gas discharged from the engine body are mixed in the mixer after passing through the first oxidation catalyst and are subject to oxidization in the second oxidation catalyst.