Outlet-coated ceramic honeycomb bodies and methods of manufacturing same

Abstract

A coated ceramic honeycomb body comprising a honeycomb structure comprising a matrix of intersecting porous walls forming a plurality of axially-extending channels, at least some of the plurality of axially-extending channels being plugged to form inlet channels and outlet channels, wherein a total surface area of the outlet channels is greater than a total surface area of the inlet channels, and wherein a catalyst is preferentially located within the outlet channels. and preferentially disposed on non-filtration walls of the outlet channels. Methods and apparatus configured to preferentially apply a catalyst-containing slurry to the outlet channels and non-filtration walls are provided, as are other aspects.

What is claimed is: 
     
         1 . A honeycomb body, comprising:
 a honeycomb structure comprising a matrix of intersecting porous walls forming a plurality of axially-extending channels, at least some of the plurality of axially-extending channels being plugged to form inlet channels and outlet channels,   wherein a total surface area of the outlet channels is greater than a total surface area of the inlet channels,   wherein some of the porous walls are filtration walls that separate inlet channels from outlet channels and some of the porous walls are non-filtration walls,   wherein the honeycomb structure comprises a pattern of a plurality of central outlet cells surrounded by a plurality of surrounding outlet cells and a plurality of inlet cells,   wherein the central outlet cells are larger in cross-sectional area than the surrounding outlet cells, and   wherein the central outlet cells comprise non-filtration walls and the surrounding outlet cells are devoid of non-filtration walls.   
     
     
         2 . The honeycomb body of  claim 1  wherein the honeycomb body further comprises a catalyst preferentially disposed on the non-filtration walls. 
     
     
         3 . The honeycomb body of  claim 2  wherein the catalyst comprises a selective catalyst reduction catalyst. 
     
     
         4 . The honeycomb body of  claim 2  wherein the inlet channels are substantially devoid of the catalyst. 
     
     
         5 . The honeycomb body of  claim 1  wherein an area ratio of the total surface area of the outlet channels to the total surface area of the inlet channels ranges from 1.2 to 4.0. 
     
     
         6 . The honeycomb body of  claim 1  wherein the area ratio ranges from 2.0 to 3.0. 
     
     
         7 . The honeycomb body of  claim 1  wherein the area ratio is two or more. 
     
     
         8 . The honeycomb body of  claim 1  wherein a total number of outlet channels is greater than a total number of inlet channels. 
     
     
         9 . The honeycomb body of  claim 1  wherein a cross-sectional area of the outlet channels is greater than a cross sectional area of inlet channels. 
     
     
         10 . The honeycomb body of  claim 2  wherein the catalyst being preferentially disposed comprises CR≤0.8, wherein CR is a coating ratio defined as an average % loading of a washcoat containing the catalyst on and within the filtration walls divided by an average % loading of the washcoat containing the catalyst on and within the non-filtration walls. 
     
     
         11 . The honeycomb body of  claim 10  wherein the catalyst being preferentially disposed comprises 0.2≤CR≤0.8. 
     
     
         12 . The honeycomb body of  claim 1  wherein the porous walls have average bulk porosity in a range from 40% to 60%. 
     
     
         13 . The honeycomb body of  claim 12  wherein the porous walls have a median pore diameter from 8 μm to 16 um. 
     
     
         14 . The honeycomb body of  claim 1  wherein the porous walls comprise average bulk porosity from 55% to 75%. 
     
     
         15 . The honeycomb body of  claim 14  wherein the porous walls comprise a median pore diameter from 14 um to 30 um. 
     
     
         16 . The honeycomb body of  claim 1  wherein the porous walls comprise an average bulk porosity from 60% to 70%, and a median pore diameter from 14 um to 25 um. 
     
     
         17 . The honeycomb body of  claim 1 , wherein the filtration walls define a square-shaped pattern extending across a cross-section of the inlet channels and across a cross-section of the outlet channels. 
     
     
         18 . The honeycomb body of  claim 1  comprising square-shaped inlet channels and square-shaped outlet channels, the square-shaped inlet channels being smaller in cross-sectional area than the square-shaped outlet channels. 
     
     
         19 . The honeycomb body of  claim 1  comprising rectangular-shaped inlet channels and square-shaped outlet channels. 
     
     
         20 . The honeycomb body of  claim 1 , comprising rectangular inlet channels and rectangular outlet channels wherein a cross-sectional area of the rectangular inlet channels is greater than a cross-sectional area of the outlet channels.