Selective catalytic reduction exhaust aftertreatment system and engine incorporating the same

Abstract

In one exemplary embodiment of the present invention, an exhaust aftertreatment system is disclosed. The system includes an oxidation catalyst (OC) that is configured to receive an exhaust gas flow from an engine. The system also includes an uncoated particulate filter (PF) that is configured to receive the exhaust gas flow from the OC. The system further also includes an exhaust fluid (EF) dosing device configured for dosing of an EF into the exhaust gas flow upstream of the uncoated PF. Still further, the system includes a selective catalyst reduction (SCR) catalyst that is configured to receive the exhaust gas flow from the uncoated PF, wherein the OC, uncoated PF and SCR catalyst comprise an exhaust aftertreatment system. A urea injector may be provided as the EF dosing device and arranged to inject urea, for example, into the exhaust gases upstream of the uncoated PF.

1 . An exhaust aftertreatment system, comprising:
 an oxidation catalyst (OC) that is configured to receive an exhaust gas flow from an engine;   an uncoated particulate filter (PF) that is configured to receive the exhaust gas flow from the OC;   an exhaust fluid (EF) dosing device configured for dosing of an EF into the exhaust gas flow upstream of the uncoated PF; and   a selective catalytic reduction (SCR) catalyst that is configured to receive the exhaust gas flow from the uncoated PF, wherein the OC, EF dosing device, uncoated PF and SCR catalyst comprise an exhaust aftertreatment system.   
     
     
         2 . The exhaust aftertreatment system of  claim 1 , further comprising a second OC that is configured to receive the exhaust gas flow from the SCR catalyst. 
     
     
         3 . The exhaust aftertreatment system of  claim 1 , wherein the uncoated PF and SCR catalyst are housed in a single housing. 
     
     
         4 . The exhaust aftertreatment system of  claim 1 , wherein the uncoated PF and SCR catalyst are each housed in a separate housing. 
     
     
         5 . The exhaust aftertreatment system of  claim 2 , wherein the uncoated PF, SCR catalyst and second OC are housed in a single housing. 
     
     
         6 . The exhaust aftertreatment system of  claim 2 , wherein the SCR catalyst and second OC are each located on a metal or ceramic substrate, or a combination thereof 
     
     
         7 . The exhaust aftertreatment system of  claim 6 , wherein SCR catalyst and second OC are each located on a monolithic, flow-through substrate. 
     
     
         8 . The exhaust aftertreatment system of  claim 1 , further comprising an HC dosing device located upstream of the OC. 
     
     
         9 . The exhaust aftertreatment system of  claim 1 , wherein the EF dosing device comprises a urea injector. 
     
     
         10 . An internal combustion engine and exhaust aftertreatment system, comprising:
 an internal combustion engine comprising an exhaust treatment system, the exhaust treatment system comprising:   an oxidation catalyst (OC) that is configured to receive an exhaust gas flow from the engine;   an uncoated particulate filter (PF) that is configured to receive the exhaust gas flow from the OC;   an exhaust fluid (EF) dosing device configured for dosing of an EF into the exhaust gas flow upstream of the uncoated PF; and   a selective catalytic reduction (SCR) catalyst that is configured to receive the exhaust gas flow from the PF.   
     
     
         11 . The exhaust aftertreatment system for an internal combustion engine of  claim 10 , further comprising a second OC that is configured to receive the exhaust gas flow from the SCR catalyst. 
     
     
         12 . The exhaust aftertreatment system for an internal combustion engine of  claim 10 , wherein the uncoated PF and SCR catalyst are housed in a single housing. 
     
     
         13 . The exhaust aftertreatment system for an internal combustion engine of  claim 10 , wherein the uncoated PF and SCR catalyst are each housed in a separate metal housing. 
     
     
         14 . The exhaust aftertreatment system for an internal combustion engine of  claim 11 , wherein the uncoated PF, SCR catalyst and second OC are housed in a single housing. 
     
     
         15 . The exhaust aftertreatment system for an internal combustion engine of  claim 11 , wherein the SCR catalyst and second OC are each located on a separate metal or ceramic substrate, or a combination thereof. 
     
     
         16 . The exhaust aftertreatment system for an internal combustion engine of  claim 15 , wherein the SCR catalyst and second OC are each located on the same monolithic, flow-through substrate. 
     
     
         17 . The exhaust aftertreatment system for an internal combustion engine of  claim 10 , further comprising an HC dosing device located upstream of the OC. 
     
     
         18 . The exhaust aftertreatment system for an internal combustion engine of  claim 10 , wherein the EF dosing device comprises a urea injector. 
     
     
         19 . A method of making an exhaust aftertreatment system, comprising:
 providing an oxidation catalyst (OC) that is configured to receive an exhaust gas flow from an engine;   fluidly connecting an uncoated particulate filter (PF) to the OC to receive the exhaust gas flow from the OC;   fluidly connecting an exhaust fluid (EF) dosing device upstream of the uncoated PF for dosing of an EF into the exhaust gas flow; and   fluidly connecting a selective catalytic reduction (SCR) catalyst to receive the exhaust gas flow from the uncoated PF, wherein the OC, EF dosing device, uncoated PF and SCR catalyst comprise an exhaust aftertreatment system.   
     
     
         20 . The method of  claim 19 , further comprising fluidly connecting a second OC to receive the exhaust gas flow from the SCR catalyst.