Catalytic burner system for dpf regeneration

Abstract

A system and method of effective regeneration of a diesel particulate filter used in the exhaust system of a diesel engine during low engine operating temperatures, is disclosed. Generally speaking, a catalytic burner system and method used in filter regeneration on a diesel engine comprises a burner diesel oxidation catalyst (BDOC) coupled to an exhaust flow of the diesel engine, a mixer fluidly coupled to the BDOC, a diesel oxidation catalyst (DOC) fluidly coupled to the mixer, and a diesel particulate filter (DPF) fluidly coupled to the DOC, wherein the BDOC directs the exhaust flow through the mixer, the DOC and the DPF during a regeneration cycle of the DPF under low engine temperature operating conditions.

What is claimed is: 
     
         1 . A catalytic burner system for use in regeneration of a filter in an exhaust system on a diesel engine, the burner system comprising:
 a burner diesel oxidation catalyst (BDOC) having an inlet for receiving an exhaust flow from the diesel engine and an outlet at an opposing end;   a mixer fluidly coupled to the outlet of the BDOC;   a diesel oxidation catalyst (DOC) fluidly coupled to the mixer; and,   a diesel particulate filter (DPF) fluidly coupled to the DOC, wherein the BDOC channels the exhaust flow through the mixer, the DOC and the DPF during a regeneration cycle of the DPF under low engine temperature operating conditions.   
     
     
         2 . The system of  claim 1 , wherein the BDOC further includes a collar positioned at the inlet of the BDOC. 
     
     
         3 . The system of  claim 2 , wherein the collar has a conical shape including a narrower opening and a wider outlet. 
     
     
         4 . The system of  claim 3 , wherein the collar directs the exhaust flow through the BDOC at a pre-determined flow rate. 
     
     
         5 . The system of  claim 1 , wherein the BDOC has a conical shape, having a narrower inlet channeling the exhaust flow toward a wider outlet. 
     
     
         6 . The system of  claim 1 , wherein the BDOC comprises a first substrate and a second substrate, wherein the second substrate is positioned downstream from the first substrate. 
     
     
         7 . The system of  claim 6 , wherein the first substrate comprises a plurality of wider channels and the second substrate comprises of plurality of narrow channels. 
     
     
         8 . The system of  claim 7 , wherein the first substrate and the second substrate are separated by a gap, wherein the gap enhances mixing of the exhaust flow between the first substrate and the second substrate. 
     
     
         9 . A method for regenerating a diesel engine particulate filter (DPF) during periods of low engine operating temperatures, the method comprising the steps of:
 channeling a portion of exhaust flow toward a first chamber;   restricting the flow velocity of the exhaust flow as it enters the chamber;   expanding the flow velocity of the exhaust flow as it leaves the chamber;   catalytically oxidizing the exhaust flow in a second chamber;   maintaining a pre-determined regeneration temperature between the first chamber and the second chamber; and,   regenerating the DPF.   
     
     
         10 . The method of  claim 9 , wherein the first chamber comprises a burner diesel oxidation catalyst (BDOC). 
     
     
         11 . The method of  claim 9 , wherein the step of restricting the flow velocity includes the first chamber comprising a BDOC having a conical shape. 
     
     
         12 . The method of  claim 9 , wherein the step of restricting the flow velocity includes the first chamber comprising a BDOC comprising a first substrate having a plurality of wide channels and a second substrate having a plurality of narrower channels. 
     
     
         13 . The method of  claim 9 , wherein the second chamber comprises a DOC. 
     
     
         14 . A method for regenerating a diesel engine particulate filter during periods of low engine operating temperatures, the method comprising the steps of:
 fluidly coupling components of an exhaust gas treatment system package to an engine exhaust system of the diesel-engine vehicle;   channeling the flow of exhaust gases through the components of the treatment system package; and,   maintaining a pre-determined temperature for regeneration.   
     
     
         15 . The method of  claim 14 , wherein the step of channeling the flow of exhaust gases comprises providing a burner diesel oxidation catalyst (BDOC) having a narrow inlet fluidly connected to an outlet wider relative to the inlet. 
     
     
         16 . The method of  claim 15 , wherein the BDOC further includes a conical collar positioned at the inlet of the BDOC, the conical collar restricting the flow of exhaust gases into the exhaust gas treatment system package. 
     
     
         17 . The method of  claim 14 , wherein the step of channeling the flow of exhaust gases comprises providing a burner diesel oxidation catalyst (BDOC) comprising a conical shape having a narrow inlet and a wider outlet for restricting the flow of exhaust gases into the exhaust gas treatment system. 
     
     
         18 . The method of  claim 14 , wherein the step of channeling the flow of exhaust gases comprises providing a burner diesel oxidation catalyst (BDOC) comprising a first substrate having a plurality of wide channels and a second substrate having a plurality of narrower channels, wherein the second substrate is positioned downstream from the first substrate. 
     
     
         19 . The method of  claim 14 , wherein the step of maintaining a pre-determined temperature for regeneration comprises providing a DOC. 
     
     
         20 . A catalytic burner system for use in regeneration of a particulate filter in an exhaust system on a diesel engine, the burner system comprising:
 means for channeling a portion of exhaust flow; and,   means for maintaining a pre-determined temperature for filter regeneration at low operating temperatures.   
     
     
         21 . The catalytic burner system of  claim 20 , wherein the means for channeling the exhaust flow comprises a first chamber having a conical collar. 
     
     
         22 . The catalytic burner system of  claim 20 , wherein the means for channeling the exhaust flow comprises a first chamber having a conical shape with a narrow inlet and a wider outlet. 
     
     
         23 . The catalytic burner system of  claim 20 , wherein the means for channeling the exhaust flow comprises a first chamber constructed from a first substrate having a plurality of wide channels and a second substrate having a plurality of narrower channels, wherein the second substrate is positioned downstream from the first substrate. 
     
     
         24 . The catalytic burner system of  claim 20 , wherein the means for maintaining a pre-determined temperature for filter regeneration at low operating temperatures comprises a second chamber.