| abstract |
internal combustion engine exhaust purification system. the present invention relates to an internal combustion engine, in which a hydrocarbon supply valve (15) and an exhaust purification catalyst (13) are arranged within an exhaust port of the engine. at the time of engine operation, the amount of hydrocarbon injection from the hydrocarbon feed valve (15) is controlled so that an amplitude of change in hydrocarbon concentration that flows into the exhaust purification catalyst (13) becomes if within a predetermined range of amplitude, and the hydrocarbon injection period from the hydrocarbon feed valve (15) is controlled so that a concentration of hydrocarbons flowing in the exhaust purification catalyst (13) vibrates within a predetermined range of the period. the exhaust purification catalyst (13) is formed so that a hydrocarbon deposition capacity at a side downstream of the exhaust purification catalyst (13) becomes higher than a hydrocarbon deposition capacity at a side upstream of the exhaust purification catalyst (13). |