Patent ID: 8557203
Filing Date: 2013-10-15
Classification: B01D,B01J,F01N

Abstract:
1. A device for the purification of diesel exhaust gases, which device comprises a zoned arrangement of catalysts, in the flow direction of the exhaust gas, (a) as a leading catalyst a first oxidation catalyst disposed on a first carrier substrate and immediately following as a trailing catalyst, a second oxidation catalyst disposed on a second carrier substrate, wherein the first and second oxidation catalysts contain palladium and platinum in their catalytically active coatings, wherein said first and second carrier substrates are through flow substrates, or (b) as a leading catalyst a first oxidation catalyst disposed on a carrier substrate and immediately following as a trailing catalyst, a second oxidation catalyst disposed on said carrier substrate, wherein said carrier substrate is a through flow substrate, wherein the first and second oxidation catalysts contain palladium and platinum in their catalytically active coatings; and further wherein the total quantity of platinum and palladium in the leading catalyst is high relative to the trailing catalyst, and further wherein the ratio of platinum to palladium in the leading catalyst is relatively low, and the ratio of platinum to palladium in the trailing catalyst is relatively high, and further wherein the loading of Pt:Pd in the leading oxidation catalyst is from 30 to 250 g/ft