Exhaust gas heater

Abstract

The invention relates to an exhaust heater for an exhaust system of an internal combustion engine, comprising a carrier arrangement (24) and a heat conductor arrangement (18) supported on the carrier arrangement, the heat conductor arrangement having at least one current-carrying heat conductor (14, 16), the at least one heat conductor being supported in relation to the carrier arrangement by at least one connecting element (32) extending in the direction of the longitudinal axis of the connecting element, at least one length compensation arrangement (44) being provided in a manner adapted to the at least one connecting element, the length compensation arrangement having a first length compensation element (46) having a first support surface (54) providing a wedge-shaped portion and a second length compensation element (48) having a second support surface (56) providing a mating wedge-shaped portion supported on the first support surface, the first length compensation element and the second length compensation element having different coefficients of thermal expansion from one another.

Description

Technical Field

[0001] The present invention relates to an exhaust heater, which allows heat to be transferred in the exhaust system of a motor vehicle to the exhaust gas flowing therein, which is injected by an internal combustion engine, so as to bring the system area, such as the catalytic converter or particulate filter, located downstream of the exhaust heater, to operating temperature more quickly, especially during the start-up phase of the running internal combustion engine. Background Technology

[0002] An exhaust heater is known from the later-published German patent application DE102021109568, in which two heat conductors, constructed substantially plate-like and provided separately from flat materials, are successively arranged along the main exhaust flow direction between two plate-like support elements of a support arrangement. The layered structure of the support elements and the heat conductors arranged between them is held together by a plurality of bolt-like connecting elements. To achieve electrical insulation of the heat conductors with respect to the support elements or with respect to each other, a plurality of support elements made of electrically insulating materials, such as ceramic materials, are respectively arranged between the support elements. Summary of the Invention

[0003] The objective of this invention is to provide an exhaust heater in which a stable connection of the components of the exhaust heater is ensured regardless of the temperature of the exhaust heater.

[0004] According to the present invention, the task is solved by an exhaust heater for an exhaust device of an internal combustion engine. The exhaust heater includes a support arrangement and a heat conductor arrangement supported on the support arrangement. The heat conductor arrangement has at least one current-carrying heat conductor, which is supported about the support arrangement by at least one connecting element extending along the longitudinal axis of a connecting element. At least one length compensation arrangement is provided in a manner that mates with the at least one connecting element. The length compensation arrangement has a first length compensation element and a second length compensation element. The first length compensation element has a first support surface providing a wedge-shaped portion, and the second length compensation element has a second support surface supported on the first support surface providing a mating wedge-shaped portion. The first length compensation element and the second length compensation element have different coefficients of thermal expansion.

[0005] By using the abutting support surfaces of two length compensation elements constructed from materials with different coefficients of thermal expansion, and through the wedge effect generated by the interaction of the two support surfaces, the length compensation element constructed with the smaller coefficient of thermal expansion expands less intensely than the other length compensation element when heated by the exhaust heater, while the other length compensation element moves or is loaded along the longitudinal axis of the connecting element. This effectively compensates for the expansion of the connected element along its longitudinal axis during heating, thus ensuring that the heat conductor arrangement structure and the support arrangement structure remain fixedly together even as the temperature increases.

[0006] To avoid electrical short circuits, it is proposed that the at least one thermal conductor is electrically insulated from the support unit of the support arrangement structure by means of at least one support unit of the support arrangement structure.

[0007] To ensure a stable structure under intense thermal and mechanical loads, the support arrangement may include two support elements that house the heat conductor arrangement between them along the longitudinal axis of the exhaust heater, and the heat conductor arrangement may be electrically insulated about each support element by means of at least one support arrangement support unit.

[0008] In a construction that can be easily implemented with a small number of components and is therefore particularly compact, at least one support structure unit can provide a length-compensated arrangement structure.

[0009] The length compensation of the connecting elements, especially during thermally determined expansion, can also be achieved by having at least one, preferably each connecting element supported by at least one length compensation arrangement structure along the longitudinal axis of the connecting element about the support structure.

[0010] In order to obtain a defined wedge interaction between the length compensation elements in the length compensation arrangement, in at least one, preferably each, length compensation arrangement, the first length compensation element may have a first connecting element penetration opening at least partially surrounded by the first support surface and / or the second length compensation element may have a second connecting element penetration opening at least partially surrounded by the second support surface.

[0011] In at least one, preferably each length compensation arrangement, the first support surface and / or the second support surface may be constructed in a truncated conical shape.

[0012] In order to make particularly effective use of the wedge effect provided by the length compensation element, it is proposed that the first support surface and the second support surface are arranged so that the support surface of the length compensation element with a smaller coefficient of thermal expansion is oriented toward the connecting element, and the first support surface and the second support surface are arranged so that the support surface of the length compensation element with a larger coefficient of thermal expansion is oriented away from the connecting element.

[0013] Especially when the support surface is designed as a truncated cone, it can be stipulated that: the first support surface and the second support surface are arranged to the support surface of the length compensation element with a smaller coefficient of thermal expansion as an inner truncated cone surface, and the first support surface and the second support surface are arranged to the support surface of the length compensation element with a larger coefficient of thermal expansion as an outer truncated cone surface.

[0014] In order to achieve a low-cost, stable and resistant-to-exhaust structure, it is proposed that in at least one, preferably each, length compensation arrangement, at least one of the first and second length compensation elements is constructed of a metallic material.

[0015] In particular, when the heat conductor arrangement structure is to be electrically supported by the length compensation arrangement structure with respect to the support arrangement structure, it is advantageous that in at least one, preferably each, length compensation arrangement structure, at least one of the first and second length compensation elements is constructed of an electrically insulating material, preferably a ceramic material.

[0016] For the support of the heat conductor arrangement or support arrangement, in at least one, preferably each length compensation arrangement, the first length compensation element may have a third support surface substantially orthogonal to the longitudinal axis of the connecting element, and / or the second length compensation element may have a fourth support surface substantially orthogonal to the longitudinal axis of the connecting element.

[0017] At least one, preferably each connecting element, may have a bolt comprising a head and an externally threaded rod, and a nut in threaded engagement with the externally threaded rod. For the purpose of supporting such connecting elements with respect to the bracket arrangement structure, it can then be further specified that in at least one, preferably each connecting element, the head and / or the nut is supported with respect to the bracket arrangement structure by means of a length-compensating arrangement structure.

[0018] A compact structural form can be supported by at least one, preferably each connecting element, including a connecting bolt that is material-locked to the bracket arrangement structure in at least one, preferably each axial end region.

[0019] The present invention also relates to an exhaust device for an internal combustion engine, the exhaust device comprising at least one exhaust heater having a construction according to the present invention. Attached Figure Description

[0020] The invention will then be described in detail with reference to the accompanying drawings. In the drawings:

[0021] Figure 1 A perspective view of the exhaust heater is shown;

[0022] Figure 2 Show Figure 1 A longitudinal sectional view of the exhaust heater;

[0023] Figure 3 The schematic diagram shows a longitudinal sectional view of an exhaust heater, which has a support unit and a length compensation arrangement structure arranged in a manner that is matched with connecting elements.

[0024] Figure 4 This illustrates an alternative design type corresponding to Figure 3 The illustration;

[0025] Figure 5 This illustrates another corresponding alternative design type. Figure 3 The illustration;

[0026] Figure 6 This illustrates another corresponding alternative design type. Figure 3 The illustration;

[0027] Figure 7 This illustrates an alternative design type corresponding to Figure 3 The illustration;

[0028] Figure 8 This illustrates another corresponding alternative design type. Figure 3 The illustration;

[0029] Figure 9 This illustrates another corresponding alternative design type. Figure 3 The illustration;

[0030] Figure 10 This illustrates another corresponding alternative design type. Figure 3 The illustration;

[0031] Figure 11 This illustrates another corresponding alternative design type. Figure 3 The illustration. Detailed Implementation

[0032] exist Figure 1 and Figure 2The diagram shows an exhaust heater 10 for an exhaust system 12 of an internal combustion engine, for example, in a motor vehicle. The exhaust heater 10 has two heat conductors 14 and 16 arranged sequentially along the longitudinal axis L of the exhaust heater, which are allowed to flow through the exhaust gas in the main exhaust flow direction H and have a heat conductor arrangement structure generally indicated by 18. These heat conductors 14 and 16 are arranged sequentially by the exhaust gas flowing substantially in the main exhaust flow direction H. The heat conductors 14 and 16 are constructed substantially in a plate-like shape or from a flat material, and their structure, provided by utilizing multiple sections extending in a corrugated structure, is produced by separating them from a flat material blank, particularly a metal blank.

[0033] On the sides of the two heat conductors 14 and 16 that are opposite to each other along the longitudinal direction L of the exhaust heater, there are generally plate-shaped support elements 20 and 22 with a support arrangement structure generally indicated by 24. The plate-shaped support elements 20 and 22 are fixed to the generally cylindrical support housing 26 on their outer peripheral regions.

[0034] The two thermal conductors 14 and 16 can be connected in series or in parallel. For electrical connection to a power source, two connector units 28 and 30 are provided that penetrate the support housing 26 and are electrically connected to the thermal conductors 14 and 16 within the internal space surrounded by the support housing 26.

[0035] To achieve a stable connection, the two support elements 20, 22 and the adjacent heat conductors 14, 16 disposed therebetween are fixedly connected to each other by a plurality of bolt-like connecting elements 32. The connecting elements 32 may be constructed, for example, as bolts having externally threaded rods 34 and heads 36. Nuts 37 are tightened onto the externally threaded rods 34 to clamp the layered structure of the support elements 20, 22 and the heat conductors 14, 16. The connecting elements 32 may be constructed, for example, of steel or a nickel-chromium alloy.

[0036] To achieve electrical insulation of the heat conductors 14 and 16 with respect to the support elements 20 and 22, which are typically constructed of metallic material, with respect to the support arrangement structure 24, a support arrangement structure support unit 38, constructed of an electrically insulating material, such as ceramic, and generally plate-shaped or gasket-shaped, is provided between the heat conductor 14 and the support element 20, for example, in a manner that mates with each connecting element 32. Similarly, a support element support unit 40 is provided between the heat conductor 16 and the support element 22, for example, in a manner that mates with each connecting element 32. The support element support units 38 and 40 may, for example, be substantially identical in structure to each other.

[0037] To support the two side-by-side heat conductors 14, 16 with electrical insulation relative to each other, heat conductor support units 42 are provided, for example, in a manner that corresponds to each connecting element 32. Each heat conductor support unit 42 is also constructed substantially in a plate shape as one or more discs and is made of ceramic material.

[0038] refer to Figures 3 to 11 The following describes different design options for the exhaust heater, particularly the connecting element 32 that holds the support arrangement 24 or its support elements 20, 22 together with the heat conductor arrangement 18 or its heat conductors 14, 16. Figures 3 to 11 The diagram shows the following regions of the heat conductors, where the connecting element 32 is positioned or penetrates the openings provided in the support elements 20, 22 or the heat conductors 14, 16. Due to the simple structural design, it is advantageous that in the respective exhaust heaters, all the following regions are constructed identically, in which the support elements 20, 22 are fixedly connected to the heat conductors 14, 16 by means of the corresponding connecting element 32. However, in principle, different designs for providing the fixed connection may be provided in such regions.

[0039] Figure 3 The schematic diagram of the exhaust heater 10 according to the invention shows two support elements 20, 22 and the area where heat conductors 14, 16 disposed therebetween are connected by means of a connecting element 32. A heat conductor support unit 42 can be seen between the two heat conductors 14, 16. Where the heat conductors 14, 16 are penetrated by the connecting element 32, a sleeve-shaped insulating element 43 can be inserted into the opening formed in the heat conductors 14, 16 to achieve the defined positioning of the connecting element 32 within the opening provided in the heat conductors 14, 16.

[0040] A length compensation arrangement structure, generally indicated by 44, is provided between the support element 20 of the support arrangement structure 24 and the support unit 38 of the support arrangement structure 24. The length compensation arrangement structure 44, which includes the connecting element 32 shown, comprises two length compensation elements 46 and 48, each having a connecting element penetration opening 50 and 52 through which the externally threaded rod 34 of the connecting element 32 passes. The first compensation element 46 is constructed with a frustoconical first support surface 54, which provides an outer frustoconical surface. The second compensation element 48 is constructed with a frustoconical second support surface 56, which provides an inner frustoconical surface and has the same cone angle as the first support surface 54 and is supported on the first support surface. The first support surface 54 provides a wedge-shaped portion that cooperates with the second support surface 56, which provides a mating wedge-shaped portion.

[0041] The two length compensation elements 46 and 48 are constructed of materials with different coefficients of thermal expansion or linear expansion. In an advantageous design, the structural material of the first length compensation element 46 has a much larger, advantageously greater, coefficient of thermal expansion than the structural material of the second length compensation element 48.

[0042] exist Figure 3 In the design example shown, the first length compensation element is supported on the bracket element 20 by a third support surface 58 that is substantially orthogonal to the longitudinal axis V of the connecting element. The second length compensation element 48 is supported on a bracket arrangement structure support unit 38 constructed of an electrically insulating material by a fourth support surface 60 that is substantially orthogonal to the longitudinal axis V of the connecting element. Because the length compensation arrangement structure 44 is electrically insulated with respect to the heat conductor arrangement structure 18, and particularly with respect to the heat conductor 14, by means of the bracket arrangement structure support unit 38, the length compensation elements 46, 48 do not necessarily need to be constructed of electrically insulating materials. Each of the length compensation elements 46, 48 may, for example, be constructed of a metallic material, and these structural materials are chosen such that the structural material of the first length compensation element 46 has a larger, and particularly much larger, coefficient of thermal expansion than the structural material of the second length compensation element. However, in principle, at least one of the two length compensation elements 46, 48 may also be constructed of an electrically insulating material, such as a ceramic material, and must also meet the following condition: the structural material of one of the two compensation elements 46, 48, preferably the structural material of the first length compensation element 46, has a larger, preferably much larger, coefficient of thermal expansion than the structural material of the corresponding other length compensation element.

[0043] During operation of such an exhaust heater 10, the temperature can rise to values ​​exceeding 900°C. This can lead to relatively strong thermal expansion of different components, particularly the connecting element 32. Excessive thermally induced elongation of the external threaded rod 34 can result in loss of the secure clamping of the components held together by the connecting element 32. However, such thermally induced linear expansion of the connecting element 32 is compensated by the length compensation arrangement 44 in such a way that the length compensation element, which expands relatively strongly under thermal influence, particularly the first length compensation element 46 constructed with a larger coefficient of thermal expansion, also expands along the longitudinal axis V of the connecting element and, through a wedge action, loads or moves the other length compensation element, i.e., the second length compensation element 48 having a smaller coefficient of thermal expansion, along the longitudinal axis V of the connecting element. Thus, the linear expansion of the connecting element 32 or its external threaded rod 34 is compensated, and the secure holding of the components clamped between the head 36 and the nut 37 is maintained. In particular, it is advantageous that a length compensation element with a larger coefficient of thermal expansion, constructed with an axial structural length smaller than that of the external threaded rod 34, has a coefficient of thermal expansion that is larger, especially much larger, than that of the structural material of the connecting element 32 or its external threaded rod 34. The coefficient of thermal expansion of a length compensation element with a smaller coefficient of thermal expansion can, for example, be smaller than that of the connecting element 32.

[0044] A changing design approach Figure 4 As shown in [the image]. Figure 4 In the design shown, the length compensation arrangement structure 44 is also disposed between the two support elements 20, 22 of the support arrangement structure 24, however, it is positioned between the support element 22 and the support unit 40 of the support arrangement structure that provides electrical insulation with respect to the thermal conductor 16. This mode of operation corresponds to the previously referenced... Figure 3 Describe how it works.

[0045] refer to Figure 3 and Figure 4 It should be noted that regardless of the location of the length compensation arrangement structure 44 constructed using the two length compensation elements 46 and 48, the length compensation arrangement structure may be installed in such a way that the second length compensation element 48 is supported by its fourth support surface 60 on one of the two support elements 20 and 22, while the first length compensation element 46 is supported by its third support surface 58 on one of the two support arrangement structure support units 38 and 40.

[0046] Figure 5A design is shown in which one of the two support structure units 38 and 40, particularly support structure unit 38, is provided by a length compensation structure 44. The second length compensation element 48 is directly supported on the heat conductor 14 by its fourth support surface 60, as if... Figure 3 As in the design, the first length compensation element 46 is supported on the support element 20 of the support arrangement structure 24 by its third support surface 58. Since the support element 20 is typically constructed of sheet metal and is therefore conductive, in this design, the thermal conductor arrangement structure 18, and in particular the thermal conductor 14, must also provide electrical insulation with respect to the support element 20 via the length compensation arrangement structure 44. For this purpose, at least one of the length compensation elements 46, 48 must be constructed of an electrically insulating material. Advantageously, the second length compensation element 48 is constructed, for example, of a ceramic material, and must also satisfy the previously described condition: the two length compensation elements 46, 48 have different, preferably significantly different, coefficients of thermal expansion.

[0047] exist Figure 5 In the design shown, the length compensation arrangement structure 44 may also be located in the region between the heat conductor 16 and the support element 22. In this design, the length compensation arrangement structure 44 may also be rotatably installed, thereby providing a first length compensation element 46 with an outer truncated cone surface supported on the heat conductors 14, 16 with its third support surface 58, and a second length compensation element 48 with its fourth support surface 60 supported on the directly adjacent support element 20 or 22.

[0048] Figure 6 In principle Figure 4 The design variant shown illustrates, exemplarily, that the structural length D of the length compensation arrangement 44 can be altered to provide the necessary length compensation function. It can be seen that this length compensation arrangement structure... Figure 6 The design shown has a significantly larger expansion along the longitudinal axis V of the connecting element, which can be, for example, in the range of 6 mm.

[0049] Figure 7 The combination of exhaust heater 10 is shown. Figure 3 and Figure 4 This is one design approach. A length compensation arrangement structure 44, having a first length compensation element 46 and a second length compensation element 48, is provided not only in conjunction with support element 20 but also in conjunction with support element 22. This enables symmetrical clamping of the heat conductors 14 and 16 between the two support elements 20 and 22 and the distribution of the length compensation function to two axially spaced regions.

[0050] exist Figure 7 In the design variant shown, at least one of the two length compensation arrangement structures 44 may also be installed such that the corresponding first length compensation element 46 is supported with respect to the respective adjacent support unit 38 or 40 of the bracket arrangement structure, while the corresponding second length compensation element 48 is supported with respect to the respective adjacent support element 20 or 22.

[0051] Figure 8 This diagram illustrates a design variation of the exhaust heater 10, in which, based on Figure 5 According to the design principle, each of the aforementioned support structure support units 38, 40 is provided by a length compensation arrangement structure 44. The length compensation arrangement structure 44 is located between each of the two heat conductors 14, 16 and the respective adjacent support elements 20, 22. Alternatively, the design can be such that a corresponding second length compensation element 48, constructed of an electrically insulating material, rests against the heat conductor 14 or 16, while a corresponding first length compensation element 46 is supported on the directly adjacent support element 20 or 22. Alternatively, the opposite installation configuration may be chosen, in which, in at least one of the length compensation arrangement structures 44, the second length compensation element 48 is supported on the respective allocated support element 20 or 22.

[0052] Figure 9 One design for the heat conductor is shown, wherein the connecting element, or each connecting element 32, is configured as a connecting bolt, which does not protrude substantially from the support elements 20, 22 of the support arrangement 24 in its two axial end regions. The connecting element 32 is inserted into the corresponding openings of the support elements 20, 22 and is fixedly connected to the connecting elements 20, 22 by, for example, circumferential welds 62, 64.

[0053] In the support path between the support unit 40 and the support element 20, a length compensation arrangement structure 44 with the previously described configuration is provided. Alternatively or additionally, such a length compensation arrangement structure 44 may also be positioned in the support path between the support element 20 and the support unit 38. Here, the design may also be such that, in one or, if necessary, two length compensation arrangement structures 44, a corresponding second length compensation element 48 is supported on the support element 20 or 22.

[0054] Figure 10This illustration shows a design for an exhaust heater in which the length compensation arrangement 44 is not positioned in the support path between the two support elements 20, 22 of the support arrangement 24, but rather in the support path between one of the support elements 20, 22, specifically the support element 20 and the connecting element 32, specifically its head 36. The second length compensation element 48 is supported on the support element 20 with its fourth support surface 60, while the head 36 of the connecting element 32 is supported on the third support surface 58 of the first length compensation element 46.

[0055] In this design, it can also be specified that the first length compensation element 46, which provides the outer truncated cone surface with its first support surface 54, has a larger, preferably much larger, coefficient of thermal expansion than the second length compensation element 48, which provides the inner truncated cone surface with its second support surface 56.

[0056] In the exhaust heater 10 Figure 11 In the design shown, the length compensation arrangement 44 is positioned in the support path between the bracket element 22 and the nut 37, such that the first length compensation element 46 is supported by its third support surface 58 about the nut 37 and the second length compensation element 48 is supported in the bracket element 22 by its fourth support surface 60.

[0057] exist Figure 10 and Figure 11 In the design shown, the structural materials of the two length compensation elements 46, 48 are also coordinated with each other such that one of the two length compensation elements 46, 48, preferably the first length compensation element 46 which is provided with a first support surface 54 with an outer truncated cone surface, has a larger, preferably much larger, coefficient of thermal expansion than the other of the two length compensation elements 46, 48.

[0058] In principle Figure 10 and Figure 11 In the design variant shown, the configuration may also be such that the first length compensation element 46 is supported on one of the two support elements 20, 22, while the second length compensation element 48 is supported on the head 36 or nut 37. The length compensation arrangement structure 44 may also be provided in a manner that mates with each of the two support elements 20, 22. Because in a design where one or both length compensation arrangements 44 are positioned in the support path between the connecting element 32 and the support arrangement structure 44, the length compensation arrangement structure does not necessarily need to satisfy electrical insulation functions, for example, the two length compensation elements 46, 48 can be constructed of conductive materials, such as metals. Again, note the previously stated condition regarding the coefficient of thermal expansion.

[0059] The exhaust heater constructed according to the present invention ensures that: even in the areas of the exhaust equipment of the internal combustion engine that are subjected to strong thermal and mechanical loading, the different components of the exhaust heater are stably connected, taking into account the corrosive loading that occurs through the exhaust of the exhaust equipment. This connection avoids complete loss of prestress for all temperatures that occur during operation and thereby ensures that the layered components of the exhaust heater are stably and gaplessly held together.

Claims

1. An exhaust heater for an exhaust device for an internal combustion engine, the exhaust heater comprising a support arrangement structure (24) and a heat conductor arrangement structure (18) supported on the support arrangement structure (24), the heat conductor arrangement structure having at least one current-carrying heat conductor (14, 16), the at least one heat conductor (14, 16) being supported about the support arrangement structure (24) by at least one connecting element (32) extending in the direction of the longitudinal axis (V) of the connecting element, and having at least one length compensation arrangement structure (44) provided in a manner cooperating with the at least one connecting element (32), the length compensation arrangement structure having a first length compensation element (46) and a second length compensation element (48), the first length compensation element having a first support surface (54) providing a wedge-shaped portion, the second length compensation element having a second support surface (56) supported on the first support surface (54) providing a mating wedge-shaped portion, the first length compensation element (46) and the second length compensation element (48) having different coefficients of thermal expansion from each other.

2. The exhaust heater according to claim 1, characterized in that, The at least one heat conductor (14, 16) is electrically insulated from the support structure (24) by means of at least one support unit (38, 40), and / or the support structure (24) comprises two support elements (20, 22) that house the heat conductor arrangement (18) therebetween along the longitudinal axis (L) of the exhaust heater, and the heat conductor arrangement (18) is electrically insulated from each support element (20, 22) by means of at least one support unit (38, 40).

3. The exhaust heater according to claim 2, characterized in that, At least one support structure unit (38, 40) provides a length-compensated arrangement structure (44).

4. The exhaust heater according to any one of claims 1 to 3, characterized in that, At least one connecting element (32) is supported about the support arrangement structure (24) along the direction of the longitudinal axis (V) of the connecting element by means of at least one length compensation arrangement structure (44).

5. The exhaust heater according to any one of claims 1 to 3, characterized in that, Each connecting element (32) is supported about the support arrangement structure (24) along the direction of the longitudinal axis (V) of the connecting element by means of at least one length compensation arrangement structure (44).

6. The exhaust heater according to any one of claims 1 to 3, characterized in that, In at least one length compensation arrangement (44), the first length compensation element (46) has a first connecting element penetration opening (50) at least partially surrounded by the first support surface (54) and / or the second length compensation element (48) has a second connecting element penetration opening (52) at least partially surrounded by the second support surface (56).

7. The exhaust heater according to any one of claims 1 to 3, characterized in that, In each length compensation arrangement (44), the first length compensation element (46) has a first connecting element penetration opening (50) at least partially surrounded by the first support surface (54) and / or the second length compensation element (48) has a second connecting element penetration opening (52) at least partially surrounded by the second support surface (56).

8. The exhaust heater according to any one of claims 1 to 3, characterized in that, In at least one length-compensating arrangement (44), the first support surface (54) and / or the second support surface (56) are constructed in a truncated conical shape.

9. The exhaust heater according to any one of claims 1 to 3, characterized in that, In each length compensation arrangement (44), the first support surface (54) and / or the second support surface (56) are constructed in a truncated cone shape.

10. The exhaust heater according to any one of claims 1 to 3, characterized in that, The first support surface (54) and the second support surface (56) are arranged to be oriented toward the support surface of the length compensation element with a smaller coefficient of thermal expansion, and the first support surface (54) and the second support surface (56) are arranged away from the support surface of the length compensation element with a larger coefficient of thermal expansion.

11. The exhaust heater according to claim 7, characterized in that, In at least one length compensation arrangement (44), the first support surface (54) and / or the second support surface (56) are constructed in a truncated cone shape, wherein the first support surface (54) and the second support surface (56) are arranged to support the length compensation element having a smaller coefficient of thermal expansion as an inner truncated cone surface, and the first support surface (54) and the second support surface (56) are arranged to support the length compensation element having a larger coefficient of thermal expansion as an outer truncated cone surface.

12. The exhaust heater according to any one of claims 1 to 3, characterized in that, In at least one length compensation arrangement structure (44), at least one of the first length compensation element (46) and the second length compensation element (48) is constructed of a metallic material.

13. The exhaust heater according to any one of claims 1 to 3, characterized in that, In each length compensation arrangement structure (44), at least one of the first length compensation element (46) and the second length compensation element (48) is constructed of a metallic material.

14. The exhaust heater according to any one of claims 1 to 3, characterized in that, In at least one length compensation arrangement (44), at least one of the first length compensation element (46) and the second length compensation element (48) is constructed of an electrically insulating material.

15. The exhaust heater according to any one of claims 1 to 3, characterized in that, In each length compensation arrangement (44), at least one of the first length compensation element (46) and the second length compensation element (48) is constructed of an electrically insulating material.

16. The exhaust heater according to claim 14, characterized in that, The electrical insulating material is a ceramic material.

17. The exhaust heater according to claim 15, characterized in that, The electrical insulating material is a ceramic material.

18. The exhaust heater according to any one of claims 1 to 3, characterized in that, In at least one length compensation arrangement (44), the first length compensation element (46) has a third support surface (58) orthogonal to the longitudinal axis (V) of the connecting element and / or the second length compensation element (48) has a fourth support surface (60) orthogonal to the longitudinal axis (V) of the connecting element.

19. The exhaust heater according to any one of claims 1 to 3, characterized in that, In each length compensation arrangement (44), the first length compensation element (46) has a third support surface (58) orthogonal to the longitudinal axis (V) of the connecting element and / or the second length compensation element (48) has a fourth support surface (60) orthogonal to the longitudinal axis (V) of the connecting element.

20. The exhaust heater according to any one of claims 1 to 3, characterized in that, At least one connecting element (32) has a bolt including a head (36) and an externally threaded rod (34) and a nut (37) in thread engagement with the externally threaded rod (34).

21. The exhaust heater according to any one of claims 1 to 3, characterized in that, Each connecting element (32) has a bolt including a head (36) and an externally threaded rod (34) and a nut (37) in thread engagement with the externally threaded rod (34).

22. The exhaust heater according to claim 20, characterized in that, At least one connecting element (32) is supported about the bracket arrangement structure (24) along the direction of the longitudinal axis (V) of the connecting element by means of at least one length compensation arrangement structure (44), and in at least one connecting element (32), the head (36) and / or the nut (37) is supported about the bracket arrangement structure (24) by means of the length compensation arrangement structure (44).

23. The exhaust heater according to claim 21, characterized in that, Each connecting element (32) is supported about the bracket arrangement structure (24) along the direction of the longitudinal axis (V) of the connecting element by means of at least one length compensation arrangement structure (44), and in each connecting element (32), the head (36) and / or the nut (37) is supported about the bracket arrangement structure (24) by means of the length compensation arrangement structure (44).

24. The exhaust heater according to any one of claims 1 to 3, characterized in that, At least one connecting element (32) has a connecting bolt that is material-locked to the bracket arrangement structure (24) in at least one axial end region.

25. The exhaust heater according to any one of claims 1 to 3, characterized in that, Each connecting element (32) has a connecting bolt that is material-locked to the bracket arrangement structure (24) in each axial end region.

26. An exhaust device for an internal combustion engine, said exhaust device comprising at least one exhaust heater (10) according to any one of claims 1 to 25.

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