EXHAUST PURIFICATION DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

An internal combustion engine wherein an exhaust purification catalyst (13) and a hydrocarbon feed valve (15) are arranged downstream of an exhaust turbine (7b) in an engine exhaust passage. A first NO x purification method which removes NO x by making a concentration of hydrocarbons which flows into the exhaust purification catalyst (13) vibrate by within predetermined ranges of amplitude and period and a second NO x purification method which utilizes an adsorption action of NO x to the exhaust purification catalyst (13) are used. A high pressure exhaust gas recirculation system (HPL) which causes recirculation of high pressure exhaust gas and a low pressure exhaust gas recirculation system (LPL) which causes recirculation of low pressure exhaust gas are provided. When performing an exhaust gas recirculation action by the low pressure exhaust gas recirculation system (LPL) while performing an NO x purification action by the second NO x purification method, if an acceleration operation is performed, the NO x purification action is switched to the NO x purification action by the first NO x purification method and the exhaust gas recirculation action is temporarily switched to the exhaust gas recirculation action by the high pressure exhaust gas recirculation system (HPL).