Exhaust gas heater

Abstract

The invention relates to an exhaust heater for an exhaust system of an internal combustion engine, comprising a carrier device (24) and a heating conductor device (18) carried on the carrier device (24), which heating conductor device has at least one heating conductor (14, 16) which is traversed by a fluid, wherein the at least one heating conductor (14, 16) is carried electrically insulated with respect to the carrier device (24) by at least one carrier device support unit (38, 40), which at least one carrier device support unit (38, 40) comprises a carrier device support element (48, 50, 60, 62) having a curved support surface (56, 58, 68, 70).

Description

Technical Field

[0001] The present invention relates to an exhaust heater that can transfer heat to the exhaust gas emitted by an internal combustion engine flowing in the exhaust system of a motor vehicle, thereby enabling the downstream system area, such as the catalytic converter or particulate filter, to reach its operating temperature more quickly, particularly during the start-up phase of the internal combustion engine operation. Background Technology

[0002] An exhaust heater is known from the later-published German patent application DE 10 2021 109 568, in which two heating conductors of a heating conductor device, provided by cutting from a flat material and having a generally plate-like or planar structure, are arranged sequentially along the main exhaust flow direction between two generally plate-like carrier elements of a carrier device constructed of sheet metal. The layered structure of the carrier elements and the heating conductors arranged between them is held together by a plurality of bolt-like connecting elements. To achieve electrical insulation of the heating conductors relative to the carrier elements or also relative to each other, a plurality of support elements made of electrically insulating material, such as ceramic material, are arranged between them. Summary of the Invention

[0003] The object of the present invention is to provide an exhaust heater in which the load generated in the area of ​​the support element used for heating the conductor element is reduced.

[0004] According to the present invention, this objective is achieved by an exhaust heater for an exhaust device of an internal combustion engine, the exhaust heater comprising a carrier device and a heating conductor device supported on the carrier device, the heating conductor device having at least one heating conductor through which fluid flows, wherein the at least one heating conductor is electrically insulated relative to the carrier device by at least one carrier device support unit, the at least one carrier device support unit comprising at least one carrier device support element having a curved support surface.

[0005] By providing a support surface that is particularly convexly curved or convexly spherical, relative movement in a rolling motion is possible between the carrier device and the heating conductor device in their mutually supporting areas, thereby avoiding loads that could cause damage to the support unit.

[0006] Specifically, it can be specified here that at least one carrier device support unit, preferably each carrier device support unit, includes a first carrier device support element having a first support surface with a convex bend and a second carrier device support element having a second support surface with a concave bend supported on the first support surface. Thus, when constructing an exhaust heater according to the invention, in at least one carrier device support unit, preferably each carrier device support unit, the two carrier device support elements act together in a ball joint manner with their mutually abutting, concave or convex bend support surfaces. This means that the components of the exhaust heater supported by the carrier device support elements relative to each other can pivot partially relative to each other without causing excessive loads that would damage the carrier device support elements constructed in this way.

[0007] To achieve stable support relative to the corresponding heating conductor, in at least one carrier device support unit, preferably each carrier device support unit, the carrier device support element can have a heating conductor support surface that is substantially non-bending. Therefore, there is a planar contact that distributes the resulting load evenly, thus preventing overload, because the interaction with the corresponding other carrier device support element, achieved in the form of a ball joint, is provided on the corresponding other side.

[0008] Furthermore, in order to provide stable support relative to the carrier device, it can be specified that in at least one carrier device support unit, preferably each carrier device support unit, the carrier device support element has a carrier device support surface that is substantially non-bending.

[0009] To ensure electrical insulation, it is recommended that at least one carrier device support unit, preferably each carrier device support unit, be constructed of an electrically insulating material, such as a ceramic material.

[0010] In structures requiring a smaller number of components, the carrier device support element can be provided by the carrier device in at least one carrier device support unit, preferably each carrier device support unit.

[0011] In order to stably hold the heating conductor device on the carrier device, the carrier device may include two carrier elements that receive the heating conductor device between themselves in a direction substantially corresponding to the longitudinal axis of the exhaust heater in the main exhaust flow direction, wherein the heating conductor device is supported relative to each carrier element by at least one carrier device support unit.

[0012] The integration of the carrier device support unit function in the carrier device can be achieved by the following method: in at least one carrier device support unit, preferably each carrier device support unit, the carrier device support element is provided by the carrier element.

[0013] For efficient heating operation, in the exhaust heater according to the invention, the heating conductor device may include at least two heating conductors arranged sequentially in the direction of the longitudinal axis of the exhaust heater, wherein the first heating conductor is supported relative to one of the carrier elements by means of at least one carrier device support unit and the second heating conductor is supported relative to another carrier element by means of at least one carrier device support unit, and at least one heating conductor support unit is arranged between the heating conductors that are directly adjacent to each other in the direction of the longitudinal axis of the exhaust heater.

[0014] To ensure stable and electrically insulating support for heating conductors directly adjacent to each other, it is recommended that: at least one heating conductor support unit, preferably each heating conductor support unit including at least one heating conductor support element constructed of an electrically insulating material, and / or including a substantially flat heating conductor support surface in correspondence with each heating conductor supported thereon.

[0015] The carrier device and the heating conductor device can be stably held together by connecting the heating conductor device to the carrier device via at least one connecting element, preferably multiple connecting elements.

[0016] Here, the corresponding carrier device support unit can be positioned in a specific way by supporting at least one carrier device support unit, preferably each carrier device support unit being passed through by a connecting element.

[0017] In another design, greater freedom in the shape and positioning of the corresponding carrier device support unit can be achieved by the following: at least one carrier device support unit, preferably each carrier device support unit is not penetrated by connecting elements.

[0018] It should be noted that the corresponding design in the positioning relative to one or more connecting elements can also be implemented in the corresponding heating conductor support unit.

[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 structure according to the present invention. Attached Figure Description

[0020] The invention will now 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 Longitudinal cross-sectional view of the exhaust heater;

[0023] Figure 3 A schematic diagram shows a longitudinal section of an exhaust heater having a carrier device support unit arranged in conjunction with connecting elements.

[0024] Figure 4 Showing the corresponding Figure 3 Illustrations of alternative implementation forms;

[0025] Figure 5 Showing the corresponding Figure 3 Additional illustrations of alternative implementation forms;

[0026] Figure 6 A longitudinal cross-sectional view of an exhaust heater having a carrier device support unit arranged between two connecting elements is shown.

[0027] Figure 7 A portion of an exhaust heater with an alternative embodiment having a carrier device support unit is shown. Detailed Implementation

[0028] exist Figure 1 and Figure 2 The diagram shows an exhaust heater 10 for an exhaust system 12 for an internal combustion engine in a motor vehicle, for example. The exhaust heater 10 has two heating conductors 14 and 16 arranged sequentially in the direction of the longitudinal axis L of the exhaust heater, and thus capable of being flowed around by exhaust gas flowing substantially in the main exhaust flow direction H, and having a heating conductor device generally indicated as 18. The heating conductors 14 and 16 are substantially plate-shaped or constructed of flat material, and can be produced by cutting from a flat material blank, particularly a metal blank, to have a structure provided by utilizing multiple segments extending in a tortuous structure.

[0029] On the sides of the two heating conductors 14 and 16 that are opposite to each other along the longitudinal direction L of the exhaust heater, there are generally plate-shaped carrier elements 20 and 22, generally indicated by 24. The plate-shaped carrier elements 20 and 22 are fixed to the generally cylindrical carrier housing 26 in their outer peripheral regions.

[0030] The two heating conductors 14 and 16 can be connected in series or in parallel. For electrical connection with a voltage source, two wiring units 28 and 30 are provided that pass through the carrier housing 26 and are electrically connected to the heating conductors 14 and 16 in the internal space surrounded by the carrier housing 26.

[0031] To achieve a stable connection, the two carrier elements 20, 22 and the adjacent heating conductors 14, 16 arranged between them are fixedly connected to each other by a plurality of bolt-like connecting elements 32. The connecting elements 32 can be constructed, for example, as bolts having a shank 34 and a head 36. For example, a nut element 37 can be screwed onto the shank 34 to clamp the layered structure of the carrier elements 20, 22 and the heating conductors 14, 16 between themselves. For example, the connecting elements 32 can be constructed of steel or a nickel-chromium alloy.

[0032] To achieve electrical insulation of the heating conductors 14, 16 relative to the carrier elements 20, 22 of the carrier device 24, which are typically constructed of metallic material, a carrier device support unit 38 is provided between the heating conductor element 14 and the carrier element 20, for example, in conjunction with each connecting element 32. This carrier device support unit is constructed of an electrically insulating material (e.g., ceramic material), is substantially plate-shaped, and passes through the area of ​​the opening provided therein by the corresponding connecting element 32. Similarly, a carrier element support unit 40 is provided, for example, in conjunction with each connecting element 32, arranged between the heating conductor 16 and the carrier element 22. The carrier element support units 38, 40, which are described in more detail below, may, for example, be substantially identical in structure to each other.

[0033] To ensure that two adjacent heating conductors 14, 16 are electrically insulated from each other, heating conductor support units 42 are provided, for example, in conjunction with each connecting element 32. Each heating conductor support unit 42 is also substantially plate-shaped with one or more discs and is constructed of ceramic material.

[0034] Regarding the design scheme of the exhaust heater 10 according to the present invention Figure 3 A schematic diagram shows two carrier elements 20, 22 and the area where heating conductors 14, 16 arranged between them are connected by a connecting element 32. A heating conductor support unit 42 is visible between the two heating conductors 14, 16, which provides a substantially flat, i.e., unbent heating conductor support surface 44, 46 in relation to each of the two heating conductors 14, 16, thereby achieving planar contact between the heating conductors 14, 16 and the heating conductor support unit 42 constructed from one or more discs.

[0035] Where the connecting element 32 passes through the heating conductors 14 and 16, a sleeve-shaped insulating element 47 can be inserted into the opening formed in the heating conductors 14 and 16 to achieve a specific positioning of the connecting element 32 in the opening provided in the heating conductors 14 and 16.

[0036] Each of the two carrier device support units 38, 40, which are configured in conjunction with the connecting element 32, includes a first carrier device support element 48, 50. Each first carrier device support element 48, 50 has a substantially flat, unbent heating conductor support surface 52, 54 for support on the corresponding heating conductor 14, 16. On the side opposite to the corresponding heating conductor 14 or 16, each first carrier device support element 48, 50 has a first support surface 56, 58 that is, for example, substantially spherical or spherically convex and curved.

[0037] Each carrier device support unit 38, 40 further includes a second carrier device support element 60, 62. Matching the carrier elements 20, 22, the second carrier device support elements 60, 62 each have substantially flat, unbent carrier device support surfaces 64, 66. On their sides opposite to the matched carrier elements 20 or 22, the second carrier device support elements 60, 62 each have, for example, spherically concave curved second support surfaces 68, 70, which interact with the matched convex curved first support surfaces 56, 58 in a spherical joint manner, and thus enable the mobility of the carrier elements 20, 22 relative to the heating conductors 14, 16 supported thereon via the carrier device support units 38, 40. This is particularly advantageous because... Figure 3 In the illustrated design variant, the two carrier device support elements 48, 50, 60, and 62 of the carrier device support units 38 and 40 are preferably constructed of electrically insulating ceramic material. Therefore, bending loads and resulting deformations occurring during operation or manufacturing can be absorbed by the internal mobility of the carrier device support units 38 and 40, without causing damage to the carrier device support elements 48, 50, 60, and 62.

[0038] In particular, which also contributes to this relative mobility, the corresponding connecting element 32 passes through the carrier element support unit 38, 40 or their carrier device support element 48, 50, 60, 62 with a movement gap in the corresponding vertex region of the protruding or recessed curved support surface 56, 58 or 68, 70 provided thereon.

[0039] exist Figure 4In the illustrated embodiment, the arrangement of the first and second carrier device support elements with the carrier elements 20, 22 and the heating conductors 14, 16 is interchanged. The first carrier device support elements 48, 50, constructed with protruding curved first support surfaces 56, 58, now support the carrier elements 20, 22, while the second carrier device support elements 60, 62, constructed with recessed curved second support surfaces 68, 70, are arranged in conjunction with the heating conductors 14, 16. Therefore, in this design, the first carrier device support elements 48, 50 provide substantially flat or uncurved carrier element support surfaces 72, 74 on their sides opposite to the corresponding first support surfaces 56, 58, while the second carrier device support elements 60, 62, supported on the heating conductors 14, 16, provide corresponding substantially uncurved, flat heating conductor support surfaces 76, 78 on their sides opposite to the corresponding second carrier device support surfaces 68, 70.

[0040] Another variant is shown Figure 5 In this variant, carrier device support elements 60, 62, correspondingly providing recessed curved second support surfaces 68, 70, are integrated into or provided by the respective carrier element 20 or 22, respectively, in conjunction with each carrier device support unit 38, 40. Since the carrier elements 20, 22 are constructed of metallic materials, such as sheet metal or the like, this design (where the carrier device support units 38, 40 are further traversed by connecting elements 32 in the top region of the respective protruding or recessed curved support surfaces) includes only a single first carrier device support element 48, 50, constructed of an electrically insulating material (e.g., ceramic material) and, in this embodiment, providing a protruding curved first support surface 56, 58.

[0041] Figure 6 A design is shown in which the carrier device support units 38, 40 and the heating conductor support unit 42, which are provided in conjunction with the heating conductor support unit 42, are not arranged in the region of a corresponding connecting element 32, but rather in the region located between two or more connecting elements 32. This allows for greater freedom in the positioning of the various support units. There is no need to restrict the position of the support elements.

[0042] Alternative implementation forms of the carrier device support unit are as follows: Figure 7The example is illustrated by means of a carrier device support unit 38. The carrier device support unit 38 includes a first carrier device support element 48, which is constructed of an electrically insulating material and has a protruding, curved first support surface 56 and a substantially flat, or rather, uncurved, heating conductor support surface 52. Even in this embodiment, the corresponding element, namely the second carrier device support element 50, is provided by the carrier device 24 or its carrier element 20. However, in this case, the carrier element 20 does not have a curved support surface, but rather a substantially uncurved second support surface 80, on which the protruding, curved first support surface 56 rests and can roll during relative movement.

[0043] In this embodiment, the first carrier device support element 48 can also be positioned such that its convex, curved first support surface 56 rests against the heating conductor 14 and its substantially uncurved rear side supports the carrier element 20. It goes without saying that in this embodiment, the second carrier device support unit or each second carrier device support unit 50 can also be constructed in this manner in conjunction with the heating conductor 16 or the carrier element 22.

[0044] Finally, it should be noted that different design variations can certainly be combined with each other. Therefore, for example, they can be arranged between the carrier element 20 and the heating conductor 14. Figure 3 The carrier device support unit 38 shown can be arranged between the carrier element 22 and the heating conductor 16. Figure 4 The carrier device support unit 40 shown. Different types of carrier device support units can also be provided in conjunction with different connecting elements 32. If the carrier device support element is integrated into the carrier element 20 or 22, the carrier device support element can provide a convex curved first support surface, while a corresponding concave curved second support surface can be provided on another carrier device support element constructed of an electrically insulating material.

Claims

1. An exhaust heater for an exhaust system of an internal combustion engine, the exhaust heater comprising a carrier device (24) and a heating conductor device (18) supported on the carrier device (24), the heating conductor device having at least one heating conductor (14, 16) through which a fluid flows, wherein, At least one heating conductor (14, 16) is electrically insulated from the carrier device (24) by at least one carrier device support unit (38, 40), the at least one carrier device support unit (38, 40) comprising at least one carrier device support element (48, 50, 60, 62) having a curved support surface (56, 58, 68, 70), characterized in that, - At least one carrier device support unit (38, 40) including at least one carrier device support element (48, 50, 60, 62) having a curved support surface (56, 58, 68, 70) includes two carrier device support elements (48, 50, 60, 62) that support each other. - One of the two carrier device support elements (48, 50, 60, 62) has a non-bending heating conductor support surface (52, 54; 76, 78) for supporting the heating conductor, and the other carrier device support element (48, 50, 60, 62) has a non-bending carrier device support surface (64, 66; 72, 74) for supporting the carrier device. - The first carrier device support element (48, 50) of the two carrier device support elements (48, 50, 60, 62) has a protruding curved first support surface (56, 58), and the second carrier device support element (60, 62) of the two carrier device support elements (48, 50, 60, 62) has a recessed curved second support surface (68, 70) supported on the first support surface (56, 58).

2. The exhaust heater according to claim 1, characterized in that, Each carrier device support unit (38, 40) includes a first carrier device support element (48, 50) having a first support surface (56, 58) with a protruding bend and a second carrier device support element (60, 62) having a second support surface (68, 70) with a concave bend supported on the first support surface (56, 58).

3. The exhaust heater according to claim 1 or 2, characterized in that, In each carrier device support unit (38, 40), the carrier device support element (48, 50, 60, 62) has a non-bending heating conductor support surface (52, 54; 76, 78).

4. The exhaust heater according to claim 1 or 2, characterized in that, In each carrier device support unit (38, 40), the carrier device support element (48, 50, 60, 62) has a non-bending carrier device support surface (64, 66; 72, 74).

5. The exhaust heater according to claim 1 or 2, characterized in that, In at least one carrier device support unit (38, 40), at least one carrier device support element (48, 50, 60, 62) is constructed using an electrically insulating material.

6. The exhaust heater according to claim 5, characterized in that, In each carrier device support unit (38, 40), each carrier device support element (48, 50, 60, 62) is constructed using an electrically insulating material.

7. The exhaust heater according to claim 1 or 2, characterized in that, In at least one carrier device support unit (38, 40), the carrier device support element (50) is provided by the carrier device (24).

8. The exhaust heater according to claim 1 or 2, characterized in that, The carrier device (24) includes two carrier elements (20, 22) that receive the heating conductor device (18) between them along the longitudinal axis (L) of the exhaust heater. The heating conductor device (18) is supported relative to each carrier element (20, 22) by means of at least one carrier device support unit (38, 40).

9. The exhaust heater according to claim 7, characterized in that, The carrier device (24) includes two carrier elements (20, 22) that receive the heating conductor device (18) between them along the longitudinal axis (L) of the exhaust heater. The heating conductor device (18) is supported relative to each carrier element (20, 22) by means of at least one carrier device support unit (38, 40), and in at least one carrier device support unit (38, 40), a carrier device support element (50) is provided by the carrier elements (20, 22).

10. The exhaust heater according to claim 9, characterized in that, In each carrier device support unit (38, 40), the carrier device support element (50) is provided by the carrier element (20, 22).

11. The exhaust heater according to claim 8, characterized in that, The heating conductor device (18) includes at least two heating conductors (14, 16) arranged sequentially along the longitudinal axis (L) of the exhaust heater. The first heating conductor (14, 16) is supported by at least one carrier device support unit (38) relative to one of the carrier elements (20, 22), and the second heating conductor (14, 16) is supported by at least one carrier device support unit (40) relative to the other of the carrier elements (20, 22). At least one heating conductor support unit (42) is arranged between the heating conductors (14, 16) that are directly adjacent to each other along the longitudinal axis (L) of the exhaust heater.

12. The exhaust heater according to claim 11, characterized in that, At least one heating conductor support unit (42) includes at least one heating conductor support element constructed of an electrically insulating material, and / or includes a flat heating conductor support surface (44, 46) in correspondence with each heating conductor (14, 16) supported on the heating conductor support unit.

13. The exhaust heater according to claim 12, characterized in that, Each heating conductor support unit (42) includes at least one heating conductor support element constructed of an electrically insulating material, and / or includes a flat heating conductor support surface (44, 46) in conjunction with each heating conductor (14, 16) supported on the heating conductor support unit.

14. The exhaust heater according to claim 1 or 2, characterized in that, The heating conductor device (18) is connected to the carrier device (24) via at least one connecting element (32).

15. The exhaust heater according to claim 14, characterized in that, The heating conductor device (18) is connected to the carrier device (24) via multiple connecting elements (32).

16. The exhaust heater according to claim 15, characterized in that, At least one carrier device support unit (38, 40) is passed through by the connecting element (32).

17. The exhaust heater according to claim 16, characterized in that, Each carrier device support unit (38, 40) is passed through by a connecting element (32).

18. The exhaust heater according to claim 14, characterized in that, At least one carrier device support unit (38, 40) is not passed through by the connecting element (32).

19. The exhaust heater according to claim 18, characterized in that, Each carrier device support unit (38, 40) is not passed through by the connecting element (32).

20. An exhaust device for an internal combustion engine, the exhaust device comprising at least one exhaust heater (10) according to any one of claims 1 to 19.

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