HEATING DEVICE FOR INSTALLATION IN A VEHICLE TANK FOR REDUCING AGENT AND VEHICLE TANK

Abstract

A heating device for installation in a vehicle tank for reducing agent, which is introduced into an exhaust tract of a motor vehicle for exhaust gas aftertreatment. The heating device includes at least one electrical heating element and a heat distribution body, wherein the at least one electrical heating element includes a PTC heating element, and wherein the PTC heating element is arranged in thermally conductive contact with the heat distribution body. According to the invention, the heat distribution body has a heat conduction device which is designed to distribute heat from the PTC heating element in a targeted manner within the heat distribution body. The invention also specifies a vehicle tank with such a heating device.

Claims

1. A heating device for installation in a vehicle tank for reducing agent, which is introduced into an exhaust tract of a motor vehicle for exhaust gas aftertreatment, comprising: at least one electrical heating element, at least one electrical heating element includes at least one PTC heating element; a heat distribution body formed from a first material which has a first thermal conductivity, the PTC heating element arranged in thermally conductive contact with the heat distribution body such that the heat distribution body is configured to transport and release heat generated by the PTC heating element; and a heat conduction device is arranged on and/or in the heat distribution body; wherein the heat conduction device is formed from a second material which has a second thermal conductivity different from the first thermal conductivity, and the heat conduction device distributes heat from the PTC heating element in a targeted manner within the heat distribution body.

2. The heating device of claim 1, further comprising: a contact surface being part of the heat distribution body, the PTC heating element located on a portion of the contact surface; a side surface being part of the PTC heating element, the side surface facing the contact surface; and a coupling element being part of the heat conduction device, the coupling element arranged directly between the side surface and the contact surface; wherein the second material of the coupling element has a higher second thermal conductivity than the first thermal conductivity.

3. The heating device of claim 2, the coupling element further comprising a metal body.

4. The heating device of claim 2, the coupling element further comprising a metal foil.

5. The heating device of claim 2, the coupling element further comprising a metal sheet.

6. The heating device of one of claim 1, the heat conduction device further comprising: at least one thermal insulation layer which is arranged at least in some regions on the surface of the heat distribution body; wherein the second material of the at least one thermal insulation layer has a lower second thermal conductivity than the first thermal conductivity.

7. The heating device of claim 1, the heat conduction device further comprising: at least one heat conduction element which is arranged at least in some regions within the heat distribution body; wherein the heat conduction element is designed to prevent or at least to reduce the release of heat to the environment of the heat distribution body.

8. The heating device of claim 1, the first material further comprising aluminum.

9. The heating device of claim 1, wherein the heat distribution body is substantially pot-shaped.

10. The heating device of claim 1, wherein the vehicle tank is part of a motor vehicle, and the vehicle tank stores a reducing agent which is introduced into an exhaust tract of the motor vehicle for exhaust gas aftertreatment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Exemplary embodiments of the invention will be explained in more detail below with reference to a drawing, in which:

[0030] FIG. 1 shows a schematic sectional illustration of a heating device, and

[0031] FIG. 2 shows a schematic sectional illustration of a vehicle tank with a heating device in an alternative embodiment.

[0032] Mutually corresponding parts are always provided with the same reference symbols in all figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0034] FIG. 1 illustrates a schematic sectional illustration of an exemplary embodiment of a heating device 1. The heating device 1 includes an electrical heating element 2 which includes a PTC heating element 3 and a heat distribution body 4 made of aluminum. The PTC heating element 3 lies in thermal contact on a contact surface 5 of the heat distribution body 4.

[0035] The PTC heating element 3 may be supplied with electrical energy via electrical connecting lines (not shown in FIG. 1) and converts electrical energy into heat during operation. The PTC heating element 3 has a dependence of the electrical resistance on the temperature. The PTC heating element 3 thus has a low electrical resistance at low temperatures, which multiplies exponentially when a defined switching temperature is exceeded. When the switching temperature is reached, the current through the PTC element 3 is reduced, with the heat output being reduced accordingly.

[0036] The heat distribution body 4 has a heat conduction device 6 which is arranged on and in the heat distribution body 4. The heat conduction device 6 is formed from a second material which has a second thermal conductivity different from aluminum and is designed to distribute heat generated by the PTC heating element 3 in a targeted manner within the heat distribution body 4.

[0037] For this purpose, a coupling element 8 is arranged between a side surface 7, facing the contact surface 5, of the PTC heating element 3 and the contact surface 5. The coupling element 8 is designed as a metal sheet with a higher second thermal conductivity than aluminum. In addition, the coupling element 8 is designed to be larger in area than the side surface 7, facing the contact surface 5, of the PTC heating element 3, and therefore a large contact area is formed between the contact surface 5 of the heat distribution body 4 and the coupling element 8, via which heat is dissipated from the coupling element 8 to the heat distribution body 4. In this way, a good thermal coupling of the PTC heating element 3 to the heat distribution body 4 and as targeted an introduction of the heat into the heat distribution body 4 as possible may be provided.

[0038] Furthermore, a thermal insulation layer 9a is arranged in some regions on the surface of the heat distribution body 4. The thermal insulation layer 9a is produced from a second material which has a lower second thermal conductivity than aluminum. It is thereby ensured that heat generated by the PTC heating element 3 and transferred to the heat distribution body 4 is not released, or only to a reduced extent, to the environment, at least in the region of the surface of the heat distribution body 4 on which the thermal insulation layer 9a is arranged, but rather remains primarily within the heat distribution body 4 and may be passed on within the latter.

[0039] In addition, a heat conduction element 10 is arranged in some regions within the heat distribution body 4 near the surface of the heat distribution body 4. The heat conduction element 10 is designed to prevent or at least to reduce the release of heat to the environment of the heat distribution body 4. The heat conduction element 10 therefore influences the heat conduction within the heat distribution body 4 likewise in such a manner that, in the region of the heat conduction element 10, heat is not released, or only to a reduced extent, to the environment, but rather primarily remains within the heat distribution body 4 and may be passed on within the latter. The heat conduction element 10 is produced from a second material which has a lower second thermal conductivity than aluminum such that the heat conduction by the heat conduction element 10 is prevented or reduced.

[0040] The targeted distribution of heat within the heat distribution body 4, influenced by the heat conduction device 6, and enables the heat conduction to extend over the entire heat distribution body and thus the heat distribution body 4 is heated as completely as possible. As a result, a surface area that is as large as possible of the heat distribution body 4 is available for dissipating the heat. This contributes to the fact that the heat flow introduced by the PTC heating element 3 into the heat distribution body 4 corresponds approximately to the heat flow that is released by the heat distribution body 4 to the environment and/or to the reducing agent, as a result of which the risk of switching off of the PTC heating element 3 due to an excessively high temperature is significantly reduced and a heat output which is as reliable and uniform as possible may be achieved.

[0041] FIG. 2 shows a schematic sectional illustration of a vehicle tank 11 with a heating device 1 in an alternative embodiment. The heating device 1 substantially corresponds to the heating device 1 illustrated in FIG. 1, wherein the heat distribution body 4 is substantially pot-shaped.

[0042] Reducing agent 14 is located in an inner region 12 of the vehicle tank housing 13. In the region of the bottom 15 of the vehicle tank 11, an opening 16 is provided, through which the heating device 1 is positioned so as to protrude into the inner region 12 of the vehicle tank 11. The heat distribution body 4 has a circumferential collar-like contact section 17 which is arranged on the outside in a sealing manner against the bottom 15 of the vehicle tank 11. The heat distribution body 4 thus separates a drying space 18 from the inner region 12 of the vehicle tank 11 which is filled with reducing agent 14. A delivery module (not illustrated) for delivering the reducing agent 14 may be accommodated in this drying space 18.

[0043] The heat conduction device 6 of the heat distribution body 4 includes the coupling element 8, which is arranged directly between the PTC heating element 3 and the heat distribution body 4, as well as two differently sized thermal insulation layers 9b, 9c, which are arranged in some regions of the surface of the heat distribution body 4. One thermal insulation layer 9b is arranged here on the surface of the heat distribution body 4 facing the inner region 12 of the vehicle tank 11 and the other thermal insulation layer 9c is arranged on the surface of the heat distribution body 4 facing the drying space 18.

[0044] The pot-shaped configuration of the heat distribution body 4 enables heat dissipation over a large area and thus a relatively large heat flow to the reducing agent 13 and thus further contributes to a reliable and rapid heating of the reducing agent 13.

[0045] The different features of the individual exemplary embodiments may also be combined with one another. The exemplary embodiments of FIGS. 1 and 2 are not of a restrictive nature and serve to illustrate the concept of the invention.

[0046] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.