Exhaust gas treatment system

Abstract

An exhaust gas aftertreatment system having a housing and a plurality of separate diesel particulate filter bricks disposed in the housing. A first one of such bricks is disposed upstream of a second one of the bricks. The second one of the bricks has channels with closed downstream ends and open upstream ends and channels with closed upstream ends and open downstream ends and the upstream brick has channels with closed downstream ends and open upstream ends and bypass channels with open upstream ends and open downstream ends.

1 . An exhaust gas aftertreatment system, comprising a filter having a plurality of bricks with channels having common, porous walls, a first one of the bricks being disposed upstream of a second one of the bricks, the upstream brick having channels with closed outlet ends and open inlet ends and bypass channels with open inlet end and open outlet ends. 
   
   
       2 . The system recited in  claim 1  wherein each one of the bricks has channels with common, porous walls, the common walls being porous to allow untrapped portions of particles in the exhaust gas to pass through such walls. 
   
   
       3 . The system recited in  claim 2  wherein the second one of the bricks has channels with closed downstream ends and open upstream ends and channels with closed upstream ends and open downstream ends and the upstream brick has channels with closed downstream ends and open upstream ends and channels with open upstream ends and open downstream ends. 
   
   
       4 . An exhaust gas aftertreatment system, comprising:
 a housing;   a plurality of separate diesel particulate filter bricks disposed in the housing, a first one of such bricks being disposed upstream of a second one of the bricks, the second one of the bricks having channels with closed downstream ends and open upstream ends and channels with closed upstream ends and open downstream ends and the upstream brick having channels with closed downstream ends and open upstream ends and bypass channels with open upstream ends and open downstream ends.   
   
   
       5 . An exhaust gas aftertreatment system, comprising:
 a first particulate filter stage brick having a plurality of channel therein, such channels having common walls, upstream ends of the channels facing an inlet flow of the exhaust gas, a first portion of the channels being bypass channels having open upstream ends and open downstream ends and a second portion of the channels being particulate trapping channels having open upstream ends and closed downstream ends to trap portions of particulates in the exhaust gas, the common walls being porous to allow untrapped portions of particles in the exhaust gas to pass between the channels;   a second particulate filter stage brick disposed having a plurality of channel therein, such channels having common walls, upstream ends of the channels facing an inlet flow of the exhaust gas processed by the first particulate filter stage, a first portion of the channels being exhaust channels having closed upstream ends and open downstream ends and a second portion of the channels being particulate trapping channels having open upstream ends and closed downstream ends to trap portions of particulates in the exhaust gas, the common walls being porous to allow untrapped portions of particles in the exhaust gas to pass between the channels.   
   
   
       6 . The exhaust gas aftertreatment system recited in  claim 5  wherein the bypass channels of the first particulate filter stage brick face the particulate trapping channels of the second particulate filter stage brick stage and wherein the particulate trapping channels of the first particulate filter stage brick face the exhaust channels of the second particulate filter stage brick stage. 
   
   
       7 . A method for treating exhaust gas, comprising:
 passing the exhaust gas through a filter having a plurality of bricks with channels having common, porous walls, a first one of the bricks being disposed downstream of a second one of the bricks, the upstream brick having closed outlet ends and open inlet ends and bypass channels with open inlet end and open outlet ends;   increasing temperature of the upstream brick generating an exothermal energy release of energy from the upstream brick to the downstream brick concurrently as a portion of the exhaust gas flows through the bypass channels in the upstream brick to the downstream brick resulting in regeneration in the downstream brick.