Heater for a device for providing a liquid additive

Abstract

The invention relates to a heater for a device for providing a liquid additive in a motor vehicle, comprising at least one switchable resistance heating element, which is connected in series with at least one switch element, by means of which the at least one resistance heating element can be activated and deactivated, and comprising at least one permanent resistance heating element, which is connected in parallel with the at least one switchable resistance heating element and the at least one switch element.

1 . A heater for a device for supplying a liquid additive in a motor vehicle comprising:
 at least one resistance heating element;   at least one switch element;   at least one switchable resistance heating element which is connected in series with the at least one switch element, where the at least one switch element is used to activate and deactivate the at least one switchable resistance heating element; and   at least one permanent resistance heating element which is connected in parallel with respect to the at least one switchable resistance heating element and the at least one switch element.   
     
     
         2 . The heater according to  claim 1 , wherein the electrical resistances of the at least one switchable resistance heating element and of the at least one permanent resistance heating element are configured such that a proportion of between 70% and 95% of the heating power of the heater is generated by the at least one switchable resistance heating element when the at least one switchable resistance heating element is activated. 
     
     
         2 . The heater according to  claim 1 , further comprising:
 at least one temperature sensor; and   at least one control component used to control the at least one switch element and the at least one switchable resistance heating element as a function of a temperature determined by the at least one temperature sensor.   
     
     
         3 . The heater according to  claim 1 , further comprising:
 a heating foil with a surface;   wherein the at least one switchable resistance heating element and the at least one permanent resistance heating element are arranged as conductor paths on the heating foil.   
     
     
         5 . The heater according to  claim 3 , wherein the heating foil ( 9 ) is flexible. 
     
     
         6 . The heater according to  claim 1 , further comprising a plurality of switchable resistance heating elements and a plurality of switch elements assigned to a corresponding one of the plurality of in switchable resistance heating elements, wherein the plurality of switchable resistance heating elements are arranged in different surface sections of the heater. 
     
     
         7 . The heater according to  claim 6 , wherein each of the plurality of switchable resistance heating elements is assigned at least one corresponding temperature sensor, and each of the plurality of switchable resistance heating elements are activated and deactivated, as a function of a temperature determined by the at least one corresponding temperature sensor, and one of the plurality of switch elements and at least one control component. 
     
     
         8 . The heater according to  claim 1 , further comprising a device for providing liquid additive in a motor vehicle, wherein the at least one electric heater is used to heat the liquid additive in the device. 
     
     
         9 . (canceled) 
     
     
         10 . The heater according to  claim 8 , the device for providing liquid additive to a motor vehicle further comprising a tank for storing the liquid additive; and
 a tank wall, the tank wall being part of the tank;   wherein the at least one electric heater is arranged on an outer side of the tank wall such that liquid additive in the tank is heated by the at least one heater through the tank wall.   
     
     
         11 . The heater according to  claim 1 , further comprising an exhaust gas treatment device, the exhaust gas treatment device being part of the motor vehicle. 
     
     
         12 . The heater according to  claim 11 , the motor vehicle further comprising
 an internal combustion engine, the exhaust-gas treatment device for purifying the exhaust gases of the internal combustion engine; and   a device for supplying liquid additive for the exhaust-gas treatment device, the heater being used with said device.