Device for use in exhaust aftertreatment system

Abstract

A device for use in an exhaust aftertreatment system for an internal combustion engine is provided. The device comprises a particulate filter system having a particulate filter (DPF) for the collection of particles from the engine and a heating unit for the intermittent burning of soot at a temperature suitable for soot combustion. The particulate filter system is arranged to switch between an operating mode for the collection of soot and an operating mode for active regeneration. A bypass line extends between the inlet and outlet of the particulate filter system. A valve disposed in the bypass line allows opening or closing of an exhaust gas flow through the bypass line, in dependence on the operating mode of the particulate filter system, by a control member.

1 . A device for use in an exhaust aftertreatment system for an internal combustion engine, comprising
 a particulate filter system having a particulate filter (DPF) for the collection of particles from the engine and a heating unit for the intermittent burning of soot at a temperature suitable for soot combustion, the particulate filter system being arranged to switch between an operating mode for the collection of soot and an operating mode for active regeneration,   a bypass line extending between the inlet and outlet of the particulate filter system,   a valve disposed in the bypass line, which allows opening or closing of an exhaust gas flow through the bypass line, and   a control member for operating the valve in dependence on the operating mode of the particulate filter system, so that the valve is open when the heating unit is activated and closed when the particulate filter has cooled down after such activation of the heating unit.   
   
   
       2 . The device as claimed in  claim 1 , wherein the valve is a so-called on/off valve, the bypass line being configured such that the part-flow through this line is sufficient so that, in the regeneration of the DPF system, the temperature in the exhaust line downstream of this system is kept at a suitable level. 
   
   
       3 . The device as claimed in  claim 1 , wherein the bypass line contains a laminar flow resistor. 
   
   
       4 . The device as claimed in  claim 1 , wherein the valve is adjustable between different control positions. 
   
   
       5 . The device as claimed in  claim 4 , wherein the valve is adjustable in steps. 
   
   
       6 . The device as claimed in  claim 4 , wherein the valve is steplessly adjustable. 
   
   
       7 . The device as claimed in  claim 4 , wherein a NOx-reducing catalyst placed downstream of the particulate filter. 
   
   
       8 . The device as claimed in  claim 1 , wherein the heating unit comprises a fuel injector. 
   
   
       9 . The device as claimed in  claim 1 , wherein the heating unit comprises a burner. 
   
   
       10 . The device as claimed in  claim 9 , wherein the heating unit additionally comprises an oxidation catalyst. 
   
   
       11 . The device as claimed in  claim 2 , wherein the bypass line contains a laminar flow resistor. 
   
   
       12 . The device as claimed in  claim 2 , wherein the valve is adjustable between different control positions. 
   
   
       13 . The device as claimed in  claim 12 , wherein the valve is adjustable in steps. 
   
   
       14 . The device as claimed in  claim 12 , wherein the valve is steplessly adjustable. 
   
   
       15 . The device as claimed in  claim 12 , wherein a NOx-reducing catalyst placed downstream of the particulate filter. 
   
   
       16 . The device as claimed in  claim 2 , wherein the heating unit comprises a fuel injector. 
   
   
       17 . The device as claimed in  claim 2 , wherein the heating unit comprises a burner. 
   
   
       18 . The device as claimed in  claim 8 , wherein the heating unit additionally comprises an oxidation catalyst.