Patent ID: 8590293

Claim:
An exhaust purification system of an internal combustion engine, comprising: an NO X storage reduction catalyst which is arranged in an engine exhaust passage, which stores NO X which is contained in exhaust gas when an air-fuel ratio of the exhaust gas is lean, and which releases stored NO X when an air-fuel ratio of inflowing exhaust gas becomes a stoichiometric air-fuel ratio or rich, a trapping filter which is arranged at an upstream side of the NO X storage reduction catalyst and which traps particulate matter which is contained in the exhaust gas, and an electronic control unit; wherein when causing the NO X storage reduction catalyst to release the stored NO X or SO X , the electronic control unit is configured to raise the trapping filter to a temperature at which at least part of the particulate matter is oxidized, make the flow rate of the exhaust gas which flows into the trapping filter drop, make the air-fuel ratio of the exhaust gas fall so that the air-fuel ratio of the exhaust gas which flows out from the trapping filter becomes the stoichiometric air-fuel ratio or rich, make the particulate matter which builds up on the trapping filter oxidize to generate carbon monoxide as carbon monoxide production control to thereby supply the NO X storage reduction catalyst with carbon monoxide, and adjust a ratio of the NO X and particulate matter present in the exhaust gas which is discharged from the engine body so that carbon monoxide which is produced from the particulate matter which builds up on the trapping filter and the NO X which builds up at the NO X storage reduction catalyst become a stoichiometric mixture ratio.