EXHAUST PURIFICATION SYSTEM OF INTERNAL COMBUSTION ENGINE

摘要

An internal combustion engine in an engine exhaust passage of which a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. If the hydrocarbon feed valve (15) feeds hydrocarbons by a period of within 5 seconds, a reducing intermediate is produced inside the exhaust purification catalyst (13). This reducing intermediate is used for NO x purification processing. At the time of engine operation, the demanded produced amount of the reducing intermediate required for reducing the NO x is calculated. The amount of production of the reducing intermediate is made to become this demanded produced amount by control of the feed amount and feed period of hydrocarbons.