Porous ceramic body to reduce emissions

Abstract

A porous ceramic honeycomb body including a substrate of intersecting porous walls forming axial channels extending from a first end face to a second end face. An active portion of the walls include a zeolite catalyst disposed inside pores thereof and/or is comprised of an extruded zeolite and a three way catalyst (TWC) is disposed on wall surfaces of at least a portion of the active portion.

1 . A method of manufacturing a ceramic article, comprising:
 disposing zeolite catalyst inside pores in walls of a first portion of walls of a porous ceramic body; and   disposing three way catalyst (TWC) on wall surfaces of at least a portion of the first portion of the walls of the porous ceramic body.   
     
     
         2 . The method of  claim 1 , wherein the TWC comprises at least one of hydrocarbon oxidation, CO oxidation, and NOx reduction catalysts. 
     
     
         3 . The method of  claim 1 , wherein the walls of the porous ceramic body define axial channels extending from a first end face to a second end face of the porous ceramic body, and
 the first portion of the walls extends at least partially from the first end face to the second end face.   
     
     
         4 . The method of  claim 1 , wherein the first portion of the walls is spaced apart from the first end face by a second portion of the walls. 
     
     
         5 . The method of  claim 4 , wherein the second portion of the walls is substantially free of zeolite catalyst inside pores of the walls. 
     
     
         6 . The method of  claim 4 , wherein the second portion of the walls has a lower density than the first portion of the walls. 
     
     
         7 . The method of  claim 4 , wherein the first portion of the walls is spaced apart from the second end face by a third portion of the walls. 
     
     
         8 . The method of  claim 7 , wherein the third portion of the walls is substantially free of zeolite catalyst inside pores of the walls. 
     
     
         9 . The method of  claim 7 , wherein the second portion of the walls and the third portion of the walls are each substantially free of zeolite catalyst inside pores of the walls. 
     
     
         10 . A porous ceramic honeycomb body, comprising:
 a substrate of porous walls forming channels extending from a first end face to a second end face; and   a three way catalyst (TWC) disposed on wall surfaces of at least a portion of the walls,   wherein the substrate comprises an extruded zeolite catalyst.   
     
     
         11 . A method of manufacturing a ceramic article, comprising:
 extruding a zeolite catalyst porous ceramic body; and   disposing three way catalyst (TWC) on wall surfaces of the walls of the porous ceramic body.   
     
     
         12 . An exhaust system, comprising:
 a porous ceramic honeycomb body, comprising:
 a substrate of porous walls forming channels extending from a first end face to a second end face; 
 an in wall zeolite catalyst disposed inside pores of a first portion of the walls; and 
 a three way catalyst (TWC) disposed on wall surfaces of at least a portion of the walls of the first portion of walls; and 
   a housing, comprising:
 an inlet configured to accept an exhaust gas stream to be purified, 
 an outlet configured to emit purified exhaust gas stream, and 
 a chamber between the inlet and outlet configured to direct the exhaust gas stream to be purified into the first end face of the substrate, wherein the substrate is disposed in the chamber. 
   
     
     
         13 . The system of  claim 12 , further comprising an engine configured to generate and output an exhaust gas stream to the inlet of the housing. 
     
     
         14 . The system of  claim 12 , wherein the substrate mounted in the chamber of the housing is close coupled to the engine. 
     
     
         15 . The system of  claim 12 , further comprising at least one of a filter and a selective catalytic reduction (SCR) catalyst configured to purify the exhaust gas stream.