Zoned catalysts for diesel applications
AssigneeBASF SE
InventorsJeffrey B. Hoke, Joseph C. Dettling
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Abstract
An oxidation catalyst composite, methods and systems for the treatment of exhaust gas emissions from an advanced combustion engine, such as the oxidation of unburned hydrocarbons (HC), and carbon monoxide (CO) and the reduction of nitrogen oxides (NOx) from a diesel engine and an advanced combustion diesel engine are disclosed. More particularly, washcoat compositions are disclosed comprising at least two washcoat layers, a first washcoat comprising a palladium component and a second washcoat containing platinum and at least about 50% of the total platinum is located in the rear of the catalyst.
Claims22
An oxidation catalyst composite for abatement of exhaust gas emissions from an engine comprising:
- a carrier substrate having a length, an inlet end and an outlet end, a diesel oxidation catalyst catalytic material on the carrier, the diesel oxidation catalyst catalytic material including a first washcoat zone and a second washcoat zone;
- the first washcoat zone comprising a first washcoat layer including one or more of platinum (Pt) and palladium (Pd) components and a first refractory metal oxide support, the first washcoat zone adjacent the inlet end of the carrier substrate;
- and
- the second washcoat zone comprising a second washcoat layer including a platinum component and a second refractory metal oxide support, the second washcoat layer adjacent the outlet end of the carrier substrate, wherein at least 50% of the platinum components are located in the second washcoat zone;
- and wherein the second washcoat layer is substantially free of palladium.
A method for treating a traditional diesel exhaust gas stream or an advanced combustion diesel exhaust gas stream comprising passing the exhaust gas stream through an inlet end towards an outlet end of a catalyzed soot filter, the exhaust gas first passing through a first washcoat zone on the filter comprising a first washcoat layer including one or more of platinum (Pt) and palladium (Pd) components and a first refractory metal oxide support, and then passing the exhaust gas stream through a second washcoat zone on the filter comprising a second washcoat layer including a platinum component and a second refractory metal oxide support, wherein at least 50% of the platinum components are located in the second washcoat zone;
- and wherein the second washcoat layer is substantially free of palladium.
Dependencies are inferred from the claim text.