| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of NOX-cleaning performance after endurance while securing the initial NOX purifying efficiency by constituting a carrier of a HC reducing means with a composite material of titania and silica or zirconia and alumina in an exhaust gas purifying device provided with a NOX occluding.reducing catalyst and the HC reducing means. SOLUTION: The HC reducing means 4 and the NOX occluding.reducing catalyst 5 are arranged from an upstream side to a downstream side of an exhaust gas passage 2 in this order. A ternary catalyst, an oxidizing catalyst, etc., are exemplified as the HC reducing means 4 and constituted by incorporating a carrier consisting of a heat resistant porous body and a catalytic noble metal. Then this carrier is composed of a composite material of at least one kind selected among the titania, silica and zirconia and the alumina. That is, the carrier of the HC reducing means 4 is an acidic material. Therefore, a formation of SOX is suppressed since a SO2 being the acidic material is hardly adsorbed to the carrier, and a sulfur poisoning of the NOX occluding material on the NOX occluding.reducing catalyst 5 arranged at downstream is suppressed. |
