EXHAUST PURIFICATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

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 10 capable of a lean burn operation includes a TWC 201 that is placed in an exhaust passage 16 of the internal combustion engine 10 and supports a precious metal in an inside thereof, an NSR catalyst 202 that is placed at an exhaust downstream side of the TWC 201 and supports a precious metal and a base in an inside thereof, and an SCR 22 that is placed in the exhaust passage 16 at a downstream side of the NSR catalyst, wherein the NSR catalyst 202 is placed in a region in which a bed temperature at a time of an operation thereof becomes 500°C to 750°C. The TWC 201 and the NSR catalyst 202 are preferably configured as an SC 20 of a tandem structure in which the TWC 201 and the NSR catalyst 202 are integrated by being serially arranged.