Particle filter and method for producing a particle filter

Abstract

The invention relates to a particle filter ( 1 ) for an exhaust gas system ( 2 ), and to a method for producing a particle filter. The particle filter ( 1 ) comprises a plurality of flow channels ( 5 ), which extend from a first end face ( 6 ) towards a second end face ( 7 ) and which are separated from one another by porous channel walls ( 8 ). On the end faces ( 6, 7 ), the flow channels ( 5 ) each have mutual closing means ( 9 ) such that an exhaust gas ( 10 ) enters a flow channel ( 5 ) that is open on the first end face ( 6 ), flows through the channel wall ( 8 ), and escapes from the particle filter ( 1 ) by way of an adjacent flow channel ( 5 ) that is open on the second end face ( 7 ). In a direction of flow ( 11 ), the channel wall ( 8 ) has, in succession, the following layers: a particle filter layer ( 13 ); an intermediate layer ( 14 ) comprising a first SCR coating ( 15 ) having a first catalytic activity ( 16 ); a second SCR coating ( 18 ) having a second catalytic activity ( 19 ), wherein the second catalytic activity ( 19 ) is different from the first catalytic activity ( 16 ).

1 - 9 . (canceled) 
     
     
         10 . A particle filter ( 1 ) for an exhaust gas system ( 2 ), the particle filter ( 1 ) comprising:
 a first end face ( 6 );   a second end face ( 7 );   a plurality of porous channel walls ( 8 ); and   a plurality of Sow channels ( 5 ) extending from the first end face ( 6 ), at which an exhaust gas ( 10 ) enters, through to the second end face ( 7 ), the flow channels ( 5 ) being separated from one another by respective ones of the porous channel walls ( 8 ), the flow channels ( 5 ) each having a closure ( 9 ) arranged alternately at the first and second end laces ( 6 ,  7 ) so that the exhaust gas ( 10 ) entering a flow channel ( 5 ) that is open at the first end face ( 6 ) flows through the channel wall ( 8 ) and flows out from the particle filter ( 1 ) through an adjacent flow channel ( 5 ) that is open at the second end face ( 7 ), each channel wall ( 8 ) having at least the following layers in succession in a flow direction ( 11 ):   a particle filter layer ( 13 ) having a porosity of from 5 to 50% and an average pore size, of from 5 to 15 μm on the exhaust gas entry side ( 12 );   an intermediate layer ( 14 ) having a porosity of from 55 to 95% and an average pore size of from 15 to 100 μm, the intermediate layer ( 14 ) comprising a first selective catalytic reduction (SCR) coating ( 15 ) having a first catalytic activity ( 16 ); and   a second SCR coating ( 18 ) having a second catalytic activity ( 19 ), different from the first catalytic activity ( 16 ), arranged on an exhaust gas exit side ( 17 ).   
     
     
         11 . The particle filter ( 1 ) as claimed in  claim 10 , wherein the second catalytic activity ( 19 ) is greater than the first catalytic activity ( 16 ). 
     
     
         12 . A process for producing a particle filter ( 1 ), the process comprising:
 providing a plurality of flow channels ( 5 ) each extending from a first end face ( 6 ) to a second end face ( 7 ) and being separated from one another by porous channel walls ( 8 );   alternately arranging closures ( 9 ) in the flow channels ( 5 ) at the first and second end faces ( 6 ,  7 );   coating the porous channel wall ( 8 ) with a first selective catalytic reduction (SCR) coating ( 15 ) having a first catalytic activity ( 16 );   coating the channel walls ( 8 ) of the flow channels ( 5 ) that are open at the second end face ( 7 ) with a second SCR coating ( 18 ) having a second catalytic activity ( 19 ), the second catalytic activity ( 19 ) being different from the first catalytic activity ( 16 );   arranging a particle filter layer ( 13 ) on channel walls ( 8 ) of the flow channels ( 5 ) that are open at the first end face ( 6 ), the particle filter layer ( 13 ) having a porosity of from 5 to 50% and an average pore size of from 5 to 15 μm.   
     
     
         13 . The process as claimed in  claim 12 , wherein at least fee channel walls ( 8 ) and the particle filter layer ( 13 ) are produced by a printing process. 
     
     
         14 . The process as claimed in  claim 12 , wherein the particle filter layer ( 13 ) is applied by a coating process. 
     
     
         15 . The process as claimed in  claim 12 , wherein the second catalytic activity ( 19 ) is greater than the first catalytic activity ( 16 ). 
     
     
         16 . The process as claimed in  claim 12 , wherein the first SCR coating ( 15 ) has a first viscosity ( 20 ) and fee second SCR coating ( 18 ) has a second viscosity ( 21 ), wherein the first viscosity ( 20 ) is less than the second viscosity ( 21 ). 
     
     
         17 . A motor vehicle ( 3 ) comprising:
 an internal combustion engine ( 4 ); and   an exhaust gas system ( 2 ), the exhaust gas system ( 2 ) having a particle filter ( 1 ) as claimed in  claim 10 .