Heating Element

Abstract

A heating element for heating a component for exhaust gas aftertreatment using ohmic resistance includes: an unheated end region; an intermediate region; and a heated end region. The unheated end region and the heated end region are separated by the intermediate region, and the intermediate region consists of a thermally insulating material configured to minimize heat flow from the heated end region to the unheated end region.

Claims

1.-7. (canceled)

8. A heating element (1) for heating a component for exhaust gas aftertreatment using ohmic resistance, the heating element (1) comprising: an unheated end region (3); an intermediate region (4); and a heated end region (5), wherein the unheated end region (3) and the heated end region (5) are separated by the intermediate region (4), and wherein the intermediate region (4) consists of a thermally insulating material configured to minimize heat flow from the heated end region (5) to the unheated end region (3).

9. The heating element (1) as claimed in claim 8, wherein the thermally insulating material is a ceramic material.

10. The heating element (1) as claimed in claim 8, further comprising: a channel guide (7) arranged through the unheated end region (3) and the intermediate region (4) and into the heated end region (5), and an electric conductor (6) arranged to pass through the channel guide (7).

11. The heating element (1) as claimed in claim 8, wherein the thermally insulating material is also configured so as to be electrically insulating.

12. The heating element (1) as claimed in claim 8, wherein heat output from the heated end region (5) toward the environment takes place exclusively in a radial direction of the heating element (1) and in an axial direction away from the intermediate region (4).

13. A component (2) for exhaust gas aftertreatment comprising: a housing; and the heating element (1) as claimed in claim 8, wherein the heating element (1) has, on the unheated end region (3) thereof, an assembly (8), configured to affix the heating element (1) on the housing for exhaust gas aftertreatment.

14. The component (2) for exhaust gas aftertreatment as claimed in claim 13, wherein the component (2) is a metal honeycomb having a hollow into which the heating element (1) is insertable.

15. The heating element (1) as claimed in claim 9, wherein the ceramic material is Al.sub.2O.sub.3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The invention will be discussed in detail below on the basis of an exemplary embodiment and with reference to the drawing. In the drawing:

[0020] The FIGURE shows a schematic section through a heating element according to the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0021] The FIGURE shows a schematic section through a heating element 1, which is inserted into a honeycomb body 2. Here, the honeycomb body 2 is shown only indicatively, with the metal foils forming the honeycomb structure, in particular, not being illustrated.

[0022] The heating element 1 has three regions. The outer unheated end region 3, the intermediate region 4 and the heated end region 5. The intermediate region 4 is formed from a thermally and electrically insulating material, with the result that the heat produced in the heated end region 5 can flow toward the unheated end region 3 only in very small amounts, if at all.

[0023] The heated end region 5 is heated by a conductor 6, through which current flows. The conductor 6 through which current flows is also passed through the unheated end region 3 and the intermediate region 4 in a channel-type structure 7. Ideally, the conductor 6 through which current flows is electrically insulated with respect to the unheated end region 3.

[0024] The heating element 1 is secured on the housing of the honeycomb body 2 by a flange 8. Thus, no path is formed via which the heat produced by the heating element 1 could flow directly into the housing of the honeycomb body 2 . The heat is discharged from the heated end region 5 substantially in the radial direction toward the honeycomb body 2 or the flow channels (not shown) of the honeycomb body 2. Heat can furthermore be discharged to the honeycomb body 2 in an axial direction of the heating element 1 away from the thermally insulating intermediate region 4.

[0025] The thermally insulating properties of the intermediate region 4 interrupt the heat path from the heated end region 5 toward the unheated end region 3.

[0026] In the FIGURE, the heating element 1 is represented as a cylindrical body. However, this is only one possible illustrative embodiment. Other geometrical configurations that exhibit the inventive features are also possible.

[0027] The exemplary embodiment in the FIGURE is in particular not of a limiting nature, and serves for illustrating the concept of the invention.

[0028] Although exemplary embodiments have been discussed in the above description, it should be noted that numerous modifications are possible. Furthermore, it should be noted that the exemplary embodiments are merely examples which are not intended to limit the scope of protection, the applications and the structure in any way. Rather, a person skilled in the art will take from the above description a guideline for implementation of at least one exemplary embodiment, wherein various modifications may be made, in particular with regard to the function and arrangement of the described components, without departing from the scope of protection as can be gathered from the claims and equivalent feature combinations.