EXHAUST PURIFICATION DEVICE OF INTERNAL COMBUSTION ENGINE

In an internal combustion engine, an exhaust purification catalyst (13), particulate filter (14), and hydrocarbon feed valve (15) are arranged in an engine exhaust passage. A low pressure exhaust gas recirculation system (LPL) is provided for making the exhaust gas downstream of the particulate filter (14) recirculate. If hydrocarbons are injected from the hydrocarbon feed valve (15), the carbon dioxide which is produced in the exhaust purification catalyst (13) is recirculated and the air-fuel ratio of the exhaust gas which flows into the exhaust purification catalyst (13) temporarily drops. At the time of regeneration of the particulate filter (14), hydrocarbons are injected from the hydrocarbon feed valve (15) so as not to overlap with this temporary drop of the air-fuel ratio.