Aftertreatment system for motor vehicle

Abstract

An aftertreatment system for an internal combustion engine includes a diesel cold start catalyst member, a lean NOx trap (LNT) member arranged directly adjacent to and downstream of the diesel cold start catalyst, and a selective catalyst reduction (SCR) member arranged downstream of the LNT. The diesel cold start catalyst is operable to reduce NOx emissions at operating temperatures below 200° C. and the LNT and SCR system are operable to reduce NOx emissions at operating temperatures above 200° C.

What is claimed is: 
     
         1 . An aftertreatment system for an internal combustion engine comprising:
 a diesel cold start catalyst member;   a lean NOx trap (LNT) member arranged directly adjacent to and downstream of the diesel cold start catalyst; and   a selective catalyst reduction (SCR) member arranged downstream of the LNT, wherein the diesel cold start catalyst is operable to reduce NOx emissions at operating temperatures below 200° C. and the LNT and SCR system are operable to reduce NOx emissions at operating temperatures above 200° C.   
     
     
         2 . The aftertreatment system according to  claim 1 , further comprising: a diesel exhaust fluid (DEF) injection system operable to introduce a diesel exhaust fluid into exhaust gases produced by the internal combustion engine. 
     
     
         3 . The aftertreatment system according to  claim 2 , wherein the DEF injection system is arranged downstream of the LNT and upstream of the SCR. 
     
     
         4 . The aftertreatment system according to  claim 2 , further comprising: a transfer tube fluidically connecting the diesel cold start catalyst and LNT with the SCR. 
     
     
         5 . The aftertreatment system according to  claim 3 , wherein the DEF injection system is fluidically connected to the transfer tube. 
     
     
         6 . The aftertreatment system according to  claim 2 , wherein the DEF injection system comprises a urea injector. 
     
     
         7 . The aftertreatment system according to  claim 1 , further comprising: at least one of an O2/NOx sensor and an exhaust gas temperature (EGT) sensor arranged upstream of the diesel cold start catalyst, and at least one of an O2/NOx sensor and an EGT sensor arranged downstream of the LNT. 
     
     
         8 . The aftertreatment system according to  claim 1 , further comprising: a first differential pressure sensor (DPS) arranged upstream of the SCR and a second DPS arranged downstream of the SCR. 
     
     
         9 . The aftertreatment system according to  claim 1 , wherein the diesel cold start catalyst and LNT are arranged in a common housing. 
     
     
         10 . The after treatment system according to  claim 1 , further comprising: a rear oxidation catalyst (ROC) arranged downstream of the SCR. 
     
     
         11 . A motor vehicle comprising:
 an internal combustion engine including an exhaust system; and   an aftertreatment system fluidically connected to the exhaust system, the aftertreatment system comprising:   a diesel cold start catalyst member;   a lean NOx trap (LNT) member arranged directly adjacent to and downstream of the diesel cold start catalyst; and   a selective catalyst reduction (SCR) member arranged downstream of the LNT, wherein the diesel cold start catalyst is operable to reduce NOx emissions at operating temperatures below 200° C. and the LNT and SCR system are operable to reduce NOx emissions at operating temperatures above 200° C.   
     
     
         12 . The motor vehicle according to  claim 11 , further comprising: a diesel exhaust fluid (DEF) injection system operable to introduce a diesel exhaust fluid into exhaust gases produced by the internal combustion engine. 
     
     
         13 . The motor vehicle according to  claim 12 , wherein the DEF injection system is arranged downstream of the LNT and upstream of the SCR. 
     
     
         14 . The motor vehicle according to  claim 12 , further comprising: a transfer tube fluidically connecting the diesel cold start catalyst and LNT with the SCR. 
     
     
         15 . The motor vehicle according to  claim 14 , wherein the DEF injection system is fluidically connected to the transfer tube. 
     
     
         16 . The motor vehicle according to  claim 10 , wherein the DEF injection system comprises a urea injector. 
     
     
         17 . The motor vehicle according to  claim 10 , further comprising: a diesel exhaust fluid (DEF) injection system arranged downstream of the LNT. 
     
     
         18 . The motor vehicle according to  claim 10 , further comprising: at least one of an O2/NOx sensor and an exhaust gas temperature (EGT) sensor arranged upstream of the diesel cold start catalyst, and at least one of an O2/NOx sensor and an EGT sensor arranged downstream of the LNT. 
     
     
         19 . The motor vehicle according to  claim 10 , further comprising: a first differential pressure sensor (DPS) arranged upstream of the SCR and a second DPS arranged downstream of the SCR. 
     
     
         20 . The motor vehicle according to  claim 10 , wherein the diesel cold start catalyst and LNT are arranged in a common housing.