Multi-zoned catalyst compositions
AssigneeBASF SE
InventorsShau-Lin F. Chen, Dennis R. Anderson
Life of this patent
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Abstract
Exhaust gas treatment substrates, and systems and methods including the same are provided. Catalyst substrates having flow properties where in configuring an outer, peripheral zone, more exhaust gas flows through a central zone as compared to the outer, peripheral zone. The outer, peripheral zone can have a trapping or adsorbing material on surfaces of its passages, or it can have a longer axial length as compared to the inner zone, or its passages can have smaller openings as compared to the inner zone. In one embodiment, an overcoat containing a trapping material such as a hydrocarbon trap is applied to an inlet end. In another embodiment, catalyst having an oxygen storage component is applied to an outlet end.
Claims23
An exhaust gas treatment catalyst composite comprising:
- a substrate comprising first and second pluralities of longitudinal passages wherein the first plurality of passages define an inner radial zone and the second plurality of passages define an outer radial zone,
- wherein internal surfaces of the first and second pluralities of longitudinal passages both comprise the same at least one catalytic layer comprising a catalytic metal on a support, and
- the second plurality of passages are configured such that more exhaust gas flows through the first plurality of passages as compared to the second plurality of passages, and wherein the internal surfaces of the second plurality of passages further comprise a layer comprising a trapping or absorbing material in the absence of precious metals.
Dependencies are inferred from the claim text.