EXHAUST GAS PURIFICATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

An ambient NO x adsorption catalyst (24) that can adsorb NO x contained in an exhaust gas in the presence of CO under standard conditions is placed in an engine exhaust gas passage, in an internal combustion engine. Until an engine post-initiation catalyst (24) is activated, the amounts of a high-boiling-point hydrocarbon and an unsaturated hydrocarbon that are contained in the exhaust gas flowing into the catalyst (24) are reduced so that the NO x -adsorbing activity cannot be deteriorated by the adhesion activity of the hydrocarbons while maintaining the CO concentration in the exhaust gas flowing into the catalyst (24) at a level higher than the concentration required for the adsorption of NO x .