EXHAUST EMISSION PURIFIER OF INTERNAL COMBUSTION ENGINE

The exhaust purification system of an internal combustion engine of the present invention is provided with an NO x storage reduction catalyst and a particulate filter which is arranged at the upstream side of the NO x storage reduction catalyst. When causing the NO x storage reduction catalyst to release the stored NO x , the particulate filter is raised to the temperature at which the particulate matter is oxidized, the flow rate of the exhaust gas which flows into the particulate filter is made to decrease, the air-fuel ratio of the exhaust gas which flows into the particulate filter is made rich, and the particulate matter which builds up on the particulate filter is made to oxidize to produce carbon monoxide.