Abstract: An exhaust emission control device of an internal combustion engine capable of effectively restoring an NSR catalyst from sulfur poisoning while suppressing reduction of fuel efficiency and worsening of emission, in the internal combustion engine including the NSR catalyst and SCR. An exhaust emission control device of an internal combustion engine capable of a lean burn operation includes a TWC that is placed in an exhaust passage of the internal combustion engine and supports a precious metal in an inside thereof, an NSR catalyst that is placed at an exhaust downstream side of the TWC and supports a precious metal and a base in an inside thereof, and an SCR that is placed in the exhaust passage at a downstream side of the NSR catalyst, wherein the NSR catalyst is placed in a region in which a bed temperature at a time of an operation thereof becomes 500° C. to 750° C.

Abstract: Concerning an internal combustion engine equipped with an NSR catalyst and an SCR, this invention is intended to provide an exhaust gas purification system for an internal combustion engine, the system being used to suppress degradation of emissions due to blow-through of NOx. The exhaust gas purification system, used for the internal combustion engine susceptible of lean-burn operation, includes an NSR catalyst disposed in an exhaust passageway of the internal combustion engine, an SCR disposed on a downstream side relative to the NSR catalyst, and an element for executing rich-spike control at a predetermined interval during lean-burn operation.