Reductant Supply System for a Waste Gas Cleaning Catalyst and a Heating Unit Therefor

Abstract

The invention relates to a reductant supply system for a waste gas cleaning catalyst of an internal combustion engine, in particular of a vehicle, comprising a reductant tank ( 3 ) for the holding of reductant, a connection line ( 4, 5 ) in order to convey reductant from the reductant tank ( 3 ) to a waste gas cleaning catalyst ( 2 ), and a pump ( 6 ) to pump reductant from the reductant tank ( 3 ) to the catalyst ( 2 ). According to the invention it is provided that at least one section of the connection line ( 4, 5 ) is configured as a corrosion-resistant metal pipe being provided with electrical terminal lugs ( 10, 11, 12, 13 ) in order to convey an electrical hating current through the connection line ( 4, 5 ) for the defrosting of reductant. The invention relates further to a heating unit for such a supply system, comprising a corrosion-resistant metal pipe ( 4 ) for immersion into the solution, which pipe can be attached to the pump ( 6 ) as intake pipe for the conveyance of the defrosted solution, and at which are affixed terminal lugs ( 10, 11 ) for the conveyance of a heating current through the metal pipe ( 4 ), which current heats up the metal pipe ( 4 ) for the defrosting of solution.

1 . A reductant supply system for a waste gas cleaning catalyst of an internal combustion engine, in particular for a vehicle, comprising:
 a reductant rank ( 1 ) for the holding of reductant;   a connection line ( 4 ,  5 ) for the conveyance of reductant from the reductant tank ( 3 ) to a waste gas cleaning catalyst ( 2 ), and   a pump ( 6 ) to pump reductant via the connection line ( 4 ,  5 ) from the reductant tank ( 3 ) to the catalyst ( 2 ),   
     characterized in that at least one section of the connection line ( 4 ,  5 ) is configured as corrosion-resistant metal pipe that is provided with terminal lugs ( 10 ,  11 ,  12 ,  13 ) in order to convey an electric heating current through the connection line ( 4 ,  5 ) for the defrosting of reductant. 
   
   
       2 . A reductant supply system according to  claim 1 , characterized in that the metal pipe ( 4 ,  23 ) extends into the reductant tank ( 3 ) wherein it is arranged in several coils ( 14 ). 
   
   
       3 . A reductant supply system according to any of above claims, characterized in that the metal pipe ( 4 ,  5 ) is constituted by several sections by means of a coupling, especially a plug-in coupling. 
   
   
       4 . A reductant supply system according to any of above claims, characterized in that the pump ( 6 ) is arranged between two sections of the connection line ( 4 ,  5 ), each of which is configured as a metal pipe and provided with terminal lugs ( 10 ,  11 ,  12 ,  13 ), wherein each of the terminal lugs ( 11 ,  12 ) closest to the pump ( 6 ) of the two metal pipes ( 4 ,  5 ) has the same voltage while in operation. 
   
   
       5 . A reductant supply system according to any of above claims, characterized in that a section of the metal pipe ( 5 ) is encased by an external pipe ( 22 ) or tube. 
   
   
       6 . A reductant supply system according to any of above claims, characterized in that a section of the metal pipe ( 5 ) is encased by a finned or corrugated tube ( 22 ) out of plastic. 
   
   
       7 . A reductant supply system according to  claim 5 , characterized by a fluid inlet and a fluid outlet in order to convey between the external tube ( 22 ) and the metal pipe ( 5 ) a heated fluid, especially a fluid to be heated by the loss of heat of the internal combustion engine. 
   
   
       8 . A reductant supply system according to any of above claims, characterized in that the connection line ( 4 ,  50 ) contains an equalizer ( 50 ,  51 ,  60 ) in order to compensate, in the case of a freezing of the reductant, for a volume expansion of the reductant in the connection line ( 4 ,  5 ). 
   
   
       9 . A reductant supply system according to  claim 8 , characterized in that the equalizer means is a volume-elastic equalizer ( 50 ,  51 ) installed in the connection line ( 4 ,  5 ) that is compressed during the freezing of reductant in order to compensate for a volume expansion of the reductant. 
   
   
       10 . A reductant supply system according to  claim 9 , characterized in that the equalizing means is a gas-filled chamber ( 51 ). 
   
   
       11 . A reduction supply system according to  claim 10 , characterized in that the gas-filled chamber ( 51 ) is configured as a gap between the inside of the connection line ( 4 ,  5 ) and the outside of a tube ( 60 ) arranged in the connection line, which tube conveys urea while in operation. 
   
   
       12 . A reductant supply system according to  claim 11 , characterized in that the tube ( 60 ) has ribs ( 61 ) on the outside, especially longitudinal ribs ( 61 ). 
   
   
       13 . A reductant supply system according to  claim 9  or  10 , characterized in that the equalizer ( 50 ) is a tube with gas-filled chambers ( 51 ). 
   
   
       14 . A reductant supply system according to any of above claims, characterized in that the metal pipe ( 4 ) has a cross-section that deviates from being circular, preferably by being oval or elliptical. 
   
   
       15 . A heating unit for the defrosting of a corrosive solution, in particular for a urea tank of a urea supply system according to any of above claims, comprising:
 a metal pipe ( 4 ) for the conveyance of the defrosted solution, wherein terminal lugs ( 10 ,  11 ) are affixed at the metal pipe ( 4 ) in order to convey a heating current through the metal pipe ( 4 ) that heats up the metal pipe ( 4 ) for the defrosting of the solution.   
   
   
       16 . A heating unit according to  claim 15 , characterized in that the metal pipe ( 4 ) is a corrosion-resistant metal pipe to be extended into the solution, which pipe can be attached as an intake pipe to a pump ( 6 ). 
   
   
       17 . A heating unit according to  claim 15  or  16 , characterized in that the wall thickness of the metal pipe ( 4 ) is between 0.1 mm and 0.3 mm. 
   
   
       18 . A heating unit according to  claim 15 ,  16  or  17 , characterized in that the inside diameter of the metal pipe ( 4 ) is between 1.0 mm and 4 mm, preferably between 1.2 mm and 3 mm. 
   
   
       19 . A heating unit according to any of the  claims 15  to  18 , characterized in that a temperature sensor ( 21 ) is affixed to the metal pipe ( 4 ). 
   
   
       20 . A heating unit according to any of the  claims 15  to  19 , characterized in that the metal pipe ( 4 ) is bent into several coils ( 14 ). 
   
   
       21 . A heating unit according to any of the  claims 15  to  20 , characterized in that at one end of the metal pipe ( 4 ) is affixed a plug-in coupling for the coupling to a pump ( 6 ). 
   
   
       22 . A heating unit according to any of the  claims 15  to  21 , characterized in that in the metal pipe ( 4 ) is arranged a volume-elastic equalizer ( 50 ,  51 ) that, with a freezing of fluid in the metal pipe ( 4 ), is compressed in order to compensate for a volume expansion of the fluid. 
   
   
       23 . Use of a metal pipe ( 4 ,  5 ) in a reductant supply system for a waste gas cleaning catalyst ( 2 ) of an internal combustion engine as a resistance heating element for the defrosting of reductant and for the conveyance of defrosted reductant.