Patent ID: 7937207

Claim:
An exhaust gas purification system for an internal combustion engine, characterized by comprising: an exhaust gas purification apparatus that purifies exhaust gas discharged from the internal combustion engine; a fuel addition apparatus that supplies fuel from upstream of said exhaust gas purification apparatus; a turbocharger including a turbine provided in an exhaust pipe upstream of said exhaust gas purification apparatus and a compressor provided at a point in an intake pipe of said internal combustion engine; a high pressure EGR apparatus that recirculates a portion of exhaust gas in the exhaust pipe upstream of said turbine into the intake pipe downstream of said compressor; a low pressure EGR apparatus that recirculates a portion of exhaust gas in the exhaust pipe downstream of said exhaust gas purification apparatus into the intake pipe upstream of said compressor; a control unit for controlling the amount of the exhaust gas recirculated by said high pressure EGR apparatus and/or the amount of the exhaust gas recirculated by said low pressure EGR apparatus to control the amount of the exhaust gas passing through said exhaust gas purification apparatus when fuel is supplied to said exhaust gas purification apparatus from said fuel addition apparatus; and a filter regeneration unit for performing a filter regeneration process of oxidizing particulate matter collected on a PM filter provided in said exhaust gas purification apparatus by supplying fuel to said PM filter from said fuel addition apparatus, wherein when said filter regeneration process is performed, said control unit makes the amount of the exhaust gas recirculated by said low pressure EGR apparatus larger as compared to when said filter regeneration process is not performed.