Electrically heated diesel particulate filter (dpf)

Abstract

A diesel particulate filter assembly includes a diesel particulate filter (DPF) and an electric heater that is integrally formed at an upstream end of the DPF. The electric heater includes a heating substrate and a resistive heating element. The heating substrate includes a central region and a boundary region around the central region. The resistive heating element includes a plurality of conductive portions. Adjacent ones of the conductive portions in the central region form a first spacing. Adjacent ones of the conductive portions in the boundary region form a second spacing. The second spacing is smaller than the first spacing.

1 . A diesel particulate filter assembly comprising:
 a diesel particulate filter (DPF); and   an electric heater that is integrally formed at an upstream end of the DPF, the electric heater including:
 a heating substrate that includes a central region and a boundary region around the central region; and 
 a resistive heating element that includes a plurality of conductive portions, wherein adjacent ones of the conductive portions in the central region form a first spacing and adjacent ones of the conductive portions in the boundary region form a second spacing that is smaller than the first spacing. 
   
     
     
         2 . The diesel particulate filter assembly of  claim 1  wherein a resistance of the plurality of conductive portions are constant per unit length of the resistive heating element. 
     
     
         3 . The diesel particulate filter assembly of  claim 1  wherein the plurality of conductive portions have equal diameters. 
     
     
         4 . The diesel particulate filter assembly of  claim 1  wherein the plurality of conductive portions have equal widths. 
     
     
         5 . The diesel particulate filter assembly of  claim 1  wherein the plurality of conductive portions are connected in series. 
     
     
         6 . The diesel particulate filter assembly of  claim 1  wherein the resistive heating element includes a heating wire embedded in the heating substrate. 
     
     
         7 . The diesel particulate filter assembly of  claim 1  wherein the resistive heating element includes a resistive coating on a surface of the heating substrate. 
     
     
         8 . The diesel particulate filter assembly of  claim 1  wherein the electric heater includes a mounting portion that surrounds the heating substrate and that secures the heating substrate to a wall of the DPF. 
     
     
         9 . The diesel particulate filter assembly of  claim 1  wherein the heating substrate includes a porous ceramic substrate. 
     
     
         10 . The diesel particulate filter assembly of  claim 1  wherein the conductive portions have a ring configuration. 
     
     
         11 . A diesel particulate filter assembly comprising:
 a DPF; and   an electric heater that is provided at an upstream end of the DPF and that includes:
 a heating substrate that includes a central region and a boundary region around the central region; and 
 a resistive heating element that is provided on the substrate and that includes a plurality of conductive portions, wherein the conductive portions in the boundary region have a resistance per unit length larger than that in the central region. 
   
     
     
         12 . The diesel particulate filter assembly of  claim 11  wherein adjacent ones of the conductive portions in the central region have a first spacing and adjacent ones of the conductive portions in the boundary region have a second spacing, wherein the first spacing is equal to the second spacing. 
     
     
         13 . The diesel particulate filter assembly of  claim 11  wherein adjacent ones of the conductive portions in the central region have a first spacing and adjacent ones of the conductive portions in the boundary region have a second spacing that is smaller than the first spacing. 
     
     
         14 . The diesel particulate filter assembly of  claim 11  wherein at least one of the conductive portions in the boundary region has a diameter smaller than that of the conductive portions outside the boundary region. 
     
     
         15 . The diesel particulate filter assembly of  claim 11  wherein at least one of the conductive portions in the boundary region has a width smaller than that of the conductive portions outside the boundary region. 
     
     
         16 . The diesel particulate filter assembly of  claim 11  wherein the conductive portions are connected in series.