Patent ID: 6254842
Filing Date: 2001-07-03
Classification: B01D,B01J,F01N,F02B,Y02T

Abstract:
A method comprising the steps of:operating a gasoline engine, having an exhaust gas outlet or an exhaust gas manifold outlet;passing an exhaust gas stream comprising carbon monoxide, hydrocarbons, and optionally nitrogen oxide, from the exhaust gas outlet or the exhaust manifold outlet of the gasoline engine to a close coupled catalyst, the close coupled catalyst comprising a close coupled catalyst composition;contacting the exhaust gas with the close coupled catalyst composition, the close coupled catalyst composition having substantially no oxygen storage components, the catalyst composition comprising:a support;a palladium component;optionally, at least one alkaline metal oxide selected from the group consisting of strontium oxide, calcium oxide and barium oxide;optionally, at least one platinum group metal component selected from the group consisting of platinum, rhodium, ruthenium and iridium components;optionally, at least one rare earth oxide selected from the group consisting of neodymium oxide and lanthanum oxide; andoptionally, a zirconium oxide;oxidizing at least some of the hydrocarbon and only a portion of the carbon monoxide in the presence of the close coupled catalyst; andpassing the exhaust gas from the close-coupled catalyst to a downstream catalyst, the downstream catalyst comprising an oxygen storage component selected from the group consisting of cerium components and praseodymium components.