Exhaust treatment system

Abstract

An exhaust gas treatment system of an internal combustion engine includes a selective catalytic reduction catalyst fluidly connected to the internal combustion engine, a particulate filter fluidly connected downstream of the selective catalytic reduction catalyst, and an induction line configured to direct a portion of a filtered exhaust flow of the internal combustion engine toward an inlet of the engine.

1 . An exhaust gas treatment system of an internal combustion engine, comprising:
 a selective catalytic reduction catalyst fluidly connected to the internal combustion engine;   a particulate filter fluidly connected downstream of the selective catalytic reduction catalyst; and   an induction line configured to direct a portion of a filtered exhaust flow of the internal combustion engine toward an inlet of the engine.   
   
   
       2 . The system of  claim 1 , further including at least one component configured to inject a flow of reductant upstream of the selective catalytic reduction catalyst. 
   
   
       3 . The system of  claim 1 , wherein the induction line is fluidly connected one of between the selective catalytic reduction catalyst and the particulate filter, downstream of the particulate filter and upstream of a clean-up catalyst of the system, or downstream of the clean-up catalyst. 
   
   
       4 . The system of  claim 1 , wherein the induction line is fluidly connected downstream of an energy extraction assembly of the exhaust gas treatment system. 
   
   
       5 . The system of  claim 1 , further including an oxidation catalyst fluidly connected upstream of the selective catalytic reduction catalyst. 
   
   
       6 . The system of  claim 5 , wherein the oxidation catalyst is configured to maintain a desired ratio of NO to NO 2  in an exhaust flow of the internal combustion engine. 
   
   
       7 . The system of  claim 1 , further including an NOx trap fluidly connected upstream of the selective catalytic reduction catalyst. 
   
   
       8 . The system of  claim 7 , wherein the NOx trap is disposed between an outlet of the internal combustion engine and an energy extraction assembly of the exhaust gas treatment system. 
   
   
       9 . The system of  claim 1 , further including a clean-up catalyst fluidly connected downstream of the selective catalytic reduction catalyst. 
   
   
       10 . The system of  claim 1 , further including a ventilation line fluidly connected to a crankcase of the internal combustion engine. 
   
   
       11 . The system of  claim 1 , further including an oxidation catalyst disposed on a substrate of the particulate filter. 
   
   
       12 . An exhaust gas treatment system of an internal combustion engine, comprising:
 a selective catalytic reduction catalyst fluidly connected to the internal combustion engine;   a particulate filter fluidly connected downstream of the selective catalytic reduction catalyst; and   a low pressure cleaned gas induction loop.   
   
   
       13 . The system of  claim 12 , wherein a component of the low pressure cleaned gas induction loop is fluidly connected one of between the selective catalytic reduction catalyst and the particulate filter, downstream of the particulate filter and upstream of a clean-up catalyst of the system, or downstream of the clean-up catalyst, and the component is configured to direct a portion of a filtered exhaust flow of the internal combustion engine toward an inlet of the internal combustion engine. 
   
   
       14 . The system of  claim 12 , further including an oxidation catalyst disposed one of on a substrate of the particulate filter or upstream of the selective catalytic reduction catalyst. 
   
   
       15 . The system of  claim 14 , wherein the oxidation catalyst is configured to maintain a desired ratio of NO to NO 2  in an exhaust flow of the internal combustion engine. 
   
   
       16 . The system of  claim 12 , further including an NOx trap fluidly connected upstream of the selective catalytic reduction catalyst. 
   
   
       17 . The system of  claim 12 , further including a clean-up catalyst fluidly connected downstream of the selective catalytic reduction catalyst. 
   
   
       18 . A method of treating an exhaust flow of an internal combustion engine, comprising:
 catalytically reducing NOx contained in the exhaust flow with a selective catalytic reduction catalyst;   filtering the exhaust flow with a particulate filter to form a cleaned exhaust flow; and   directing a portion of the cleaned exhaust flow to an inlet of the internal combustion engine.   
   
   
       19 . The method of  claim 18 , further including collecting NOx contained within the exhaust flow with an NOx trap fluidly connected upstream of the selective catalytic reduction catalyst. 
   
   
       20 . The method of  claim 18 , further including removing reductant from the exhaust flow with a catalyst fluidly connected downstream of the selective catalytic reduction catalyst.