Electrical heating system for a motor vehicle

Abstract

The invention relates to an electrical heating device (10) for a motor vehicle with a heating resistor designed as a conductor track (12) on a substrate (20), wherein the conductor track is at least partially arranged in a bifilar format. The invention further relates to a motor vehicle having such an electrical heating system.

Claims

1. An electrical heating device for a motor vehicle, said heating device comprising: a substrate; a heating resistor on the substrate, wherein the heating resistor being a conductor track arranged on the substrate at least in part in a bifilar manner, wherein a portion of the conductor track is divided into multiple heating paths that are insulated with respect to one another by at least one path-insulating region such that the multiple heating paths that are insulated with respect to one another are electrically connected to one another in parallel and wherein another portion of the conductor track is undivided, and wherein the conductor track includes precisely two deflections.

2. The heating device as claimed in claim 1, wherein the heating device is a high voltage device.

3. The heating device as claimed in claim 1, wherein the conductor track is routed in such a manner that straight sections of the conductor track that have current flowing in opposing directions are arranged adjacent to one another.

4. The heating device as claimed in claim 1, wherein the conductor track is arranged at least in part in a spiral or coil-shaped manner.

5. The heating device as claimed in claim 4, wherein the conductor track includes straight sections that are mutually connected by deflections.

6. The heating device as claimed in claim 1, wherein the conductor track is covered by an insulating layer.

7. A vehicle having a heating device as claimed in claim 1.

8. The heating device as claimed in claim 1, wherein a wider insulating region is provided proximal a conductor track deflection at which the conductor track changes direction into an opposing direction compared to an insulating region proximal a section of the conductor track upstream or downstream of the deflection.

9. An electrical heating device for a motor vehicle, said heating device comprising: a heating resistor including a conductor track having current flowing therethrough, said conductor track having at least two sections, wherein the current flowing through one of said at least two sections flows in a direction opposite to the current flowing through another of said at least two sections adjacent to said one of said at least two sections, wherein a portion of the conductor track is divided into multiple heating paths that are insulated with respect to one another by at least one path-insulating region such that the heating paths that are insulated with respect to one another are electrically connected to one another in parallel and wherein another portion of the conductor track is undivided.

10. The heating device as claimed in claim 9, in which said conductor track is formed on a substrate dissipating heat generated by the current flowing through said at least two sections.

11. The heating device as claimed in claim 9, wherein the conductor track includes precisely two deflections.

12. The heating device as claimed in claim 9, wherein the conductor track is routed in a bifilar manner.

13. The heating device as claimed in claim 9, wherein the conductor track is arranged at least in part in a spiral or coil-shaped manner.

14. The heating device as claimed in claim 9, wherein a wider insulating region is provided proximal a conductor track deflection joining two of said at least two sections compared to an insulating region proximal a section of the conductor track upstream or downstream of the deflection.

15. The heating device as claimed in claim 8, wherein a narrower conductor track region is provided proximal the deflection compared to a conductor track region distal the deflection.

16. The heating device as claimed in claim 14, wherein a narrower conductor track region is provided proximal the deflection compared to a conductor track region distal the deflection.

Description

(1) In the drawings:

(2) FIG. 1 illustrates a plan view of a conductor track of an electrical heating system for a motor vehicle;

(3) FIG. 2 illustrates an enlarged view of a part region of the conductor track in FIG. 1; and

(4) FIG. 3 illustrates schematically an arrangement of the conductor track on a substrate.

(5) In the case of the description hereinunder of the drawings, like reference numerals describe like or comparable components.

(6) FIG. 1 illustrates a plan view of an electrical heating device 10 for a motor vehicle having a heating resistor that is embodied as a conductor track 12. The heating resistor 12 comprises a first connector 14 and a second connector 16 that are mutually connected by means of the conductor track 12. If a supply voltage is applied to the connectors 14 and 16, the heating resistor that is embodied by means of the conductor track 12 heats up. The conductor track 12 is arranged on an adhesive layer 18 that is arranged on a substrate 20. The adhesive layer 18 is almost entirely covered by means of the conductor track 12 while the substrate 20 is in turn almost entirely covered by the adhesive layer 18. As a consequence, almost the entire substrate is covered by the conductor track 12. This leads to a particularly good use of space and a uniform heat distribution. In this example, the substrate 20 is an aluminum substrate that is embodied as a heat exchanger. As a consequence, heat that is produced by means of the conductor track is dissipated by way of the substrate. The adhesive layer 18 is a layer of aluminum oxide. The conductor track 12 is routed in a spiral or coil-shaped manner having straight sections in a bifilar manner. In particular, conductor track sections that are supplied with a current in opposing directions in each case lie adjacent to one another at the deflection sections and the straight sections. The conductor track is produced by means of a laser method from a nickel-chrome layer that was applied to the adhesive layer 18 by means of a suitable method. In this embodiment, it is provided that the conductor track 12 is divided in the heating region along its length in each case into two part paths by means of a continuous, path-insulating region 22 and said part paths are supplied with current in a parallel manner. It is also feasible that one or more path-insulating regions 22 are only arranged in sections by way of example in the region of deflections or that more than two parallel routed part paths are embodied. In this case, multiple parallel insulating regions can be used. By way of example, the insulating regions can be embodied by means of forming a gap in the conductive material of the conductor track or by means of inserting insulating material in a gap of this type. Sections of the conductor track that have a current that is flowing in opposing directions are in each case electrically insulated with respect to one another by means of an insulating region 24. In FIG. 1, the insulating regions 22 and section-insulating regions 24 alternate in each case as seen from the exterior towards the interior. As is evident in FIG. 1, two deflecting regions 26, 28 are provided in the interior of the helical shape of the conductor track 12 in which the conductor track 12 is deflected in each case into the opposing direction. A wider insulating region 30, 32 is provided in each case in the region of this deflection. These insulating regions 30, 32 are embodied in this case in a drop-shaped manner and compel a current flow in the region of the deflections 26, 28 as far as possible by way of the entire width of the conductor track 12. It is also possible to make the conductor track narrower, in particular to reduce the width of the conductor track rather than widen the insulating region. In addition to the two deflections into the opposing direction, said deflections making it particularly easy to distribute the current in a uniform manner, the conductor track 12 only comprises right-angled deflections. It is fundamentally feasible also to provide a wider insulating region and/or to reduce the width of the conductor track 12 in regions of the right-angled deflections.

(7) FIG. 2 illustrates an enlarged illustration of a lower region of the electrical heating system in FIG. 1. The deflecting region 26 is particularly evident in which the conductor track 12 is routed into the opposing direction. The drop-shaped form of the insulating region 32 is clearly illustrated in this example in the region of the deflection and said drop-shaped form of the insulating region leads to a uniform current flow around the deflection 26.

(8) FIG. 3 illustrates a cross-sectional view of the heating device 10 in FIGS. 1 and 2 in a view from the right-hand side that corresponds to a view from the direction of the arrow that is illustrated in FIG. 1. The heating device 10 comprises the substrate 20 to which the adhesive layer 18 is attached. The adhesive layer 18 can be electrically insulating and can be produced by way of example by means of oxidation of a metal material of the substrate 20, for instance oxidation of aluminum. The conductor track 12 is arranged on the adhesive layer 18. The conductor track 12 can be applied to the adhesive layer 18 by means of a suitable method, for instance a printing, injection molding, casting or plasma method. An insulating region 24 of the conductor track 12 is evident in this view and said insulating region separates from one another different sections of the conductor track through which current flows in opposite directions.

(9) Insofar as the above description refers to a plasma method, it should be understood that in lieu of this, in general a thermal injection molding method can also be used. The structure of the conductor track that is mentioned in the above description can be produced by means of a printing method. The method that is used to produce the conductor track can potentially be combined with a masking technique in order to further minimize achievable structure widths or rather to accelerate and/or to simplify the production of the structure. By way of example, it is possible in the above description when using a plasma injection molding method to achieve a fine structure having minimal structural widths of approximately 0.5 mm, by way of example a conductor track spacing of approximately 0.5 mm, with the aid of masking tape for a meandering heat conducting layer. It is then potentially possible to omit an additional process of treating the structure using lasers. The height of the conductor track that is described in the above description can expediently amount to 30 m, preferably between 5 m to 20 m and in particular between 10 m and 15 m on the substrate. Greater heights/thicknesses of the conductor track by way of example up to 1 mm are of course also possible. The height/thickness of the conductor track can be crucial for setting a cross section of the conductor track in order to establish or rather to influence the resistance of said conductor track. The insulating material that is mentioned in the above description can comprise by way of example silicones and/or polymers or can be embodied from silicones or polymers. The conductor track that is disclosed in the above description can also be embodied from an electrically conductive ceramic material. By way of example, a conductive ceramic material of this type can comprise titanium dioxide (TiO.sub.2). The substrate that is disclosed in the above description can also comprise ceramics that have a comparatively high heat-conducting value for ceramics, by way of example Al.sub.2O.sub.3 or AlN, or rather mixtures in the form of metal matrix compound materials that can likewise comprise a comparatively high heat-conducting capability. The substrate can alternatively also be embodied from one or more of these basic materials/basic material groups.

(10) The features of the invention that are disclosed in the above description, in the drawings and also in the claims can be fundamental both individually as also in a user-defined combination for implementing the invention.

LIST OF REFERENCE NUMERALS

(11) 10 Heating Device 12 Conductor Track 14 First Connector 16 Second Connector 18 Adhesive Layer 20 Substrate 22 Path-Insulating Region 24 Insulating Region 26 Deflecting Region 28 Deflecting Region 30 Insulating Region 32 Insulating Region