Electrical heating device

Abstract

The present invention relates to a PTC based heating device for a motor vehicle, preferably with electrical propulsion, in which one or a plurality of supplementary circuits are connected to a heating circuit for being switched in optionally. In this way it is possible to use a large number of possibilities for temperature control for energy management which is important in electric vehicles.

1 . A heating device for a motor vehicle, the heating device comprising:
 a heating circuit with a liquid medium as heat transfer medium,   an electrical PTC heating element, arranged in the heating circuit, for heating the liquid medium, and   a supplementary circuit with a separate heat source which can be optionally switched into the heating circuit.   
     
     
         2 . The heating device according to  claim 1 , further comprising a control device for controlling the PTC heating element, wherein the PTC heating element is controlled such that it contributes a proportion of the total heating power which cannot be provided via the supplementary circuit. 
     
     
         3 . The heating device according to  claim 1 , further comprising a control device for controlling the switching of the supplementary circuit, so that a heating requirement of the heating device is first of all covered by switching in the supplementary circuit. 
     
     
         4 . The heating device according to  claim 1 , wherein the switching of the supplementary circuit occurs with the aid of valves. 
     
     
         5 . The heating device according to  claim 1 , further comprising a pump for producing a circulation of the liquid medium in the heating circuit. 
     
     
         6 . The heating device according to  claim 1 , wherein the separate heat source of the supplementary circuit is supplied from waste heat of a vehicle component. 
     
     
         7 . The heating device according to  claim 6 , wherein the motor vehicle is a hybrid electric vehicle, and wherein the waste heat is made available from a range extender internal combustion engine of the hybrid vehicle. 
     
     
         8 . The heating device according to  claim 1 , furthermore comprising a temperature probe arranged in the heating circuit, wherein the heating device is controlled such that a temperature measured by the temperature probe is adjusted to a specified temperature target value. 
     
     
         9 . The heating device according to  claim 1 , wherein the supplementary circuit is switched off when the supplementary circuit cannot provide any heat for heating. 
     
     
         10 . The heating device according to  claim 1 , comprising at least one further supplementary circuit which can be switched in optionally. 
     
     
         11 . The heating device according to  claim 1 , wherein the supplementary circuit is switched in when the temperature in the heating circuit is to be reduced and the liquid medium in the supplementary circuit, which is switched in, is colder than in the heating circuit. 
     
     
         12 . The heating device according to  claim 1 , wherein the PTC heating element is controlled in dependence of a predetermined heating power. 
     
     
         13 . The heating device according to  claim 2 , wherein the PTC heating element is controlled in dependence of a predetermined heating power. 
     
     
         14 . The heating device according to  claim 12 , wherein the predetermined heating power is equal to the difference between the required total heating power and a heating power which can be covered by the supplementary circuit. 
     
     
         15 . The heating device according to  claim 10 , wherein the supplementary circuit, heats a specific region or a specific component of the motor vehicle. 
     
     
         6 . The heating device according to  claim 1 , wherein the PTC heating element, a control device, valves for switching a supplementary circuit in and out, and a pump for producing a circulation of the liquid medium are arranged in a common housing.  17 . The heating device according to  claim 1 , wherein the PTC heating element, the control device, valves for switching a supplementary circuit in and out, and a pump for producing a circulation of the liquid medium are arranged in a common housing. 
     
     
         18 . The heating device according to  claim 1 , wherein the motor vehicle is electrically propelled.