Filter for the aftertreatment of exhaust gases of internal combustion engines
AssigneeUmicore AG & Co. KG
InventorsMassimo Colombo, Jan Schoenhaber, Meike Antonia Gotthardt, Carolin Braun
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Abstract
The present invention relates to a wall-flow filter for removing particles from the exhaust gas of an internal combustion engine, which comprises a coating F, which comprises a sintered material S, wherein material S comprises an oxide, oxide-hydroxide, carbonate, sulphate, silicate, phosphate, mixed oxide, composite oxide, molecular sieve or a mixture comprising two or more of these materials.
Claims21
Wall-flow filter for removing particles from the exhaust gas of an internal combustion engine, which comprises a wall-flow filter substrate of length L and coating F, wherein the wall-flow filter substrate has channels E and A extending in parallel between a first and a second end of the wall-flow filter substrate, which are separated by porous walls and form surfaces OE and OA, and wherein the channels E are closed at the second end and the channels A are closed at the first end, and wherein coating F is located on the surfaces OE, optionally in the porous walls but not on the surfaces OA,
- characterized in that coating F comprises a sintered material S, wherein material S comprises kaolin, gypsum, bentonite, montmorillonite or a mixture comprising two or more of these materials, wherein
- coating F is applied onto the surfaces OE by depositing material S in powder form onto the channels E, followed by a thermal treatment to cause sintering of material S, and the thermal treatment comprises heating the wall-flow filter substrate which carries material S on its surfaces OE to a temperature T and maintaining this temperature for a period of time M, and the wall-flow filter substrate is heated with a heating rate of 100 to 1000 K/h to a temperature T of 100 to 1350° C. and maintained at that temperature for a period of time M of 1 second to twelve hours;
- and said wall-flow filter further comprising coating Z, which is coated on the surfaces OA and comprises palladium and/or rhodium and at least one cerium/zirconium mixed oxide, with the at least one cerium/zirconium mixed oxide comprising yttria and lanthana or praseodymia and lanthana;
- and wherein coating Z extends from the second end of the wall flow filter substrate to 40 to 97% of the length L of the wall-flow filter.
A wall-flow filter for removing particles from the exhaust gas of an internal combustion engine, comprising:
- a wall-flow filter substrate of length L;
- coating F;
- and
- coating Z,
- wherein the wall-flow filter substrate has channels E and A extending in parallel between a first and a second end of the wall-flow filter substrate, which are separated by porous walls and form surfaces OE and OA, and wherein the channels E are closed at the second end and the channels A are closed at the first end, and wherein coating F is located on the surfaces OE, optionally in the porous walls but not on the surfaces OA,
- wherein coating F comprises a sintered material S, wherein material S comprises kaolin, gypsum, bentonite, montmorillonite or a mixture comprising two or more of these materials, and
- wherein coating Z comprises one of (i), (ii) or (iii);
- with
- (i) being lanthanum-stabilized alumina, rhodium, palladium, or palladium and rhodium and a cerium/zirconium/rare earth metal mixed oxide which contains yttria and lanthana as rare earth metal oxides;
- (ii) being lanthanum-stabilized alumina, rhodium, palladium, or palladium and rhodium and a cerium/zirconium/rare earth metal mixed oxide which contains praseodymia and lanthana as rare earth metal oxides;
- and
- (iii) being lanthanum-stabilized alumina, rhodium, palladium, or palladium and rhodium and a first cerium/zirconium/rare earth metal mixed oxide which contains praseodymia and lanthana as rare earth metal oxides and a second cerium/zirconium/rare earth metal mixed oxide which contains yttria and lanthana as rare earth metal oxide, and
- wherein coating Z extends from the second end of the wall flow filter substrate to 40 to 97% of the length L of the wall-flow filter.
Dependencies are inferred from the claim text.