Catalytically active particulate filter
AssigneeUmicore AG & Co. KG
InventorsJan Schoenhaber, Naina Deibel, Martin Roesch, Stephanie Spiess
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Abstract
The present invention relates to a particulate filter which comprises a wall flow filter of length L and two different catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form the surfaces OE and OA, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end. The invention is characterized in that the coating Y is located in the channels E on the surfaces OE and the coating Z is located in the channels A on the surfaces OA.
Claims14
Particulate filter for removing particles, carbon monoxide, hydrocarbons and nitrogen oxides out of the exhaust gas of combustion engines operated with stoichiometric air/fuel mixture, comprising a wall flow filter of length L and two different coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls, which form surfaces OE and OA, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end, characterized in that coating Y is located in the channels E on the surfaces OE and extends from the first end of the wall flow filter over a length of 51 to 90% of length L, and coating Z is located in the channels A on the surfaces OA and extends from the second end of the wall flow filter over a length of 51 to 90% of length L, and wherein
- the coatings Y and Z contain one or more precious metals fixed to one or more carrier materials, and one or more oxygen storage components,
- the coatings Y and Z both comprise lanthanum-stabilized aluminum oxide, palladium, rhodium or palladium and rhodium and an oxygen storage component comprising zirconium oxide, cerium oxide, lanthanum oxide, and yttrium oxide and/or praseodymium oxide, and
- coating Z comprises an additional oxygen storage component which contains zirconium oxide, cerium oxide, lanthanum oxide, and praseodymium oxide and/or yttrium oxide.
Particulate filter which comprises a wall flow filter of length L and two different coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls forming surfaces OE and OA, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end, characterized in that
- coating Y is located in channels E on the surfaces OE and extends from the first end of the wall flow filter to 57 to 65% of length L and contains aluminum oxide in an amount of 35 to 60% by weight based on the total weight of coating Y, palladium, rhodium or palladium and rhodium and an oxygen storage component in an amount of 40 to 50% by weight based on the total weight of coating Y, wherein the oxygen storage component comprises zirconium oxide, cerium oxide, lanthanum oxide and yttrium oxide, and
- coating Z is located in channels A on the surfaces OA and extends from the second end of the wall flow filter to 57 to 65% of length L and contains aluminum oxide in an amount of 30 to 50% by weight based on the total weight of the coating, palladium, rhodium or palladium and rhodium and oxygen storage components in a total amount of 50 to 80% by weight based on the total weight of coating Z, wherein an oxygen storage component contains zirconium oxide, cerium oxide, lanthanum oxide and yttrium oxide and another zirconium oxide, cerium oxide, lanthanum oxide and praseodymium oxide.
Dependencies are inferred from the claim text.