Exhaust gas heater and exhaust arrangement for an internal combustion engine

Abstract

The invention relates to an exhaust gas heater for an exhaust arrangement of an internal combustion engine, comprising a carrier device, a heating conductor device carried on the carrier device, which has heating conductors through which an electric current flows, the heating conductors being carried electrically insulated with respect to the carrier device by a carrier device support unit or / and with respect to one another by a heating conductor support unit, the carrier device support unit comprising an insulating coating applied to the carrier device or / and an insulating coating applied to the heating conductors, the heating conductors being supported on the carrier device by the carrier device support unit, or / and the heating conductor support unit comprising an insulating coating applied to one of the heating conductors supported with respect to one another by the heating conductor support unit and / or an insulating coating applied to the other of the heating conductors supported with respect to one another by the heating conductor support unit. The invention also relates to an exhaust arrangement for an internal combustion engine.

Description

Technical Field

[0001] The present invention relates to an exhaust gas heater that transfers heat to the exhaust gas flowing within the exhaust system of a motor vehicle, which is emitted by an internal combustion engine, thereby enabling downstream system areas, such as catalytic converters or particulate filters, to reach operating temperature more quickly, particularly during the initial stages of engine operation. Background Technology

[0002] A waste gas heater is known from the later-published German patent application DE102021109568, in which two heating conductors of a heating conductor device are arranged sequentially along the main flow direction of the waste gas, corresponding to the longitudinal direction of the waste gas heater, between two substantially plate-shaped carrier elements of a carrier device made of metallic material. The heating conductors are provided by being separated from the flat material and are substantially plate-shaped or planar. The layered structure of the carrier elements and the heating conductors disposed between them is held together by a connecting device having multiple bolt-shaped connecting elements. To achieve electrical insulation of the heating conductors with respect to the carrier elements or also with respect to each other, a plurality of support units made of electrically insulating material, such as ceramic material, are correspondingly provided between the heating conductors and the carrier elements. Summary of the Invention

[0003] The objective of this invention is to provide an exhaust gas heater in which one or more heating conductors are supported on a carrier device or on another heating conductor in a manner and method that remains stable even at high operating temperatures.

[0004] According to the present invention, this task is solved by an exhaust gas heater for an internal combustion engine exhaust system, the exhaust gas heater comprising:

[0005] Carrier device;

[0006] A heating conductor device supported on a carrier device, the heating conductor device having at least one heating conductor through which current flows, wherein at least one heating conductor is electrically insulated from the carrier device by at least one carrier device support unit, or / and at least one heating conductor is electrically insulated from another heating conductor by a heating conductor support unit.

[0007] Wherein, at least one carrier device support unit includes an insulating coating applied to the carrier device and / or an insulating coating applied to a heating conductor, the heating conductor being supported on the carrier device by the carrier device support unit; or / and at least one heating conductor support unit includes an insulating coating applied to one of the heating conductors supported by the heating conductor support unit with respect to each other and / or an insulating coating applied to another of the heating conductors supported by the heating conductor support unit with respect to each other.

[0008] In the exhaust gas heater constructed according to the invention, a corresponding insulating coating is fixedly connected only to one of two components that are electrically insulated from each other, on which the insulating coating is applied. There is no fixed connection with the other component, thereby enabling relative movement between the mutually supporting components, particularly by vibration or different thermal expansion, without generating mechanical stress.

[0009] The fixed connection between such insulating coatings and the components containing them can be achieved, for example, by applying at least one, preferably each, insulating coating by deposition, such as vapor deposition, or by coating in a flowable state.

[0010] To provide a mechanically stable, temperature-resistant yet still electrically insulating coating, at least one, preferably each, insulating coating may be made of an inorganic insulating material, preferably a ceramic material.

[0011] For a stable construction of the exhaust gas heater, the carrier device may include two carrier elements that house the heating conductor device between themselves along the longitudinal axis of the exhaust gas heater. Here, at least one, preferably each carrier device support unit may include an insulating coating applied to one of the carrier elements.

[0012] Alternatively or additionally, it may be specified that at least one, preferably each carrier device support unit, includes an insulating coating applied to one of the heating conductors of the heating conductor device.

[0013] To achieve a fixed but still electrically insulated connection between the carrier device and the heating conductor device, the heating conductor device can be connected to the carrier device by means of a plurality of bolt-like connecting elements, wherein at least one, preferably each, connecting element passes through at least one, preferably each, heating conductor of the heating conductor device in the region of the connecting element opening. Here, at least one, preferably each, connecting element is surrounded by an insulating element in the longitudinal region of its passage through the connecting element opening.

[0014] The present invention also relates to an exhaust device for an internal combustion engine, the exhaust device comprising at least one exhaust gas heater constructed according to the invention. Attached Figure Description

[0015] The invention will now be described in detail with reference to the accompanying drawings. Wherein:

[0016] Figure 1 A perspective view of the exhaust gas heater is shown;

[0017] Figure 2 Show Figure 1 A longitudinal sectional view of the exhaust gas heater;

[0018] Figure 3 A detailed diagram of the exhaust gas heater is shown, in which the heating conductor of the heating conductor device is disposed between two carrier elements of the carrier device and supported about the two carrier elements by an insulating coating;

[0019] Figure 4 This illustrates an alternative design scheme corresponding to Figure 3 The view. Detailed Implementation

[0020] In reference Figure 3 and Figure 4 Before describing in detail the manner and method according to the invention, which electrically and insulate the heating conductor device on the waste gas heater carrier device, refer to... Figure 1 and Figure 2 The basic construction of such an exhaust gas heater 10 for use in an internal combustion engine exhaust system 12 (e.g., in a motor vehicle) is described.

[0021] The exhaust gas heater 10 has two heating conductors 14 and 16 in the exhaust device 12, through which exhaust gas flows in the main exhaust gas direction H, and which are generally identified as 18. These heating conductors are arranged to be sequentially arranged along the longitudinal axis L of the exhaust gas heater and thus can be circulated in turn by the exhaust gas flowing substantially in the main exhaust gas direction H. The heating conductors 14 and 16 are substantially plate-shaped or made of flat material, and their structure can be produced by separating them from a flat material blank, particularly a metal blank, using multiple segments extending in a curved structure.

[0022] On the sides of the two heating conductors 14 and 16 that are opposite to each other along the longitudinal axis L of the exhaust gas heater, there are carrier elements 20 and 22, generally identified as 24, which are basically plate-shaped. The plate-shaped carrier elements 20 and 22 are fixed to the basically columnar carrier housing 26 in their outer circumferential region.

[0023] The two heating conductors 14 and 16 can be connected in series or in parallel. For electrical connection to the power supply, two connection units 28 and 30 are provided that pass through the carrier housing 26. The connection units are electrically connected to the heating conductors 14 and 16 in the internal space surrounded by the carrier housing 26.

[0024] To achieve a stable connection, the two carrier elements 20, 22 and the heating conductors 14, 16 disposed between them and directly adjacent to each other are fixedly connected to each other by a plurality of bolt-like connecting elements 32. The connecting elements 32 may, for example, be configured as bolts having a rod 34 and a head 36. For example, a nut element 37 may be screwed onto the rod 34 to clamp the layered structure consisting of the carrier elements 20, 22 and the heating conductors 14, 16 between the head 36 and the nut element 37.

[0025] To achieve electrical insulation between the heating conductors 14 and 16 and the carrier elements 20 and 22, which are typically made of metallic material, the carrier device 24 is provided with a carrier device support unit 38, for example, in conjunction with each connecting element 32, between the heating conductor 14 and the carrier element 20. This carrier device support unit is made of an electrically insulating material, such as ceramic, and is essentially plate-shaped, with the connecting element 32 passing through an opening therein. Similarly, a carrier element support unit 40 is provided, for example, in conjunction with each connecting element 32, between the heating conductor 16 and the carrier element 22.

[0026] To ensure that the two side-by-side heating conductors 14, 16 are electrically insulated from each other, a heating conductor support unit 42 is provided, for example, in conjunction with each connecting element 32. Each heating conductor support unit 42 is also substantially plate-shaped and has one or more disc-shaped components and is made of ceramic material.

[0027] Where the heating conductors 14 and 16 are passed through by the connecting element 32 in the areas of the corresponding connecting element openings 44 and 46, a sleeve-shaped insulating element 48, for example made of ceramic material, is embedded in the connecting element openings 44 and 46 (formed in the heating conductors 14 and 16) to achieve a defined positioning of the connecting element 32 in the openings (provided in the heating conductors 14 and 16).

[0028] Next, refer to Figure 3 and Figure 4 In detail, according to the principles of the present invention, in the exhaust gas heater 10, by means of the aforementioned construction described regarding its basic structure, it is possible to electrically and insulately support the heating conductor device 18 along the longitudinal axis L of the exhaust gas heater by means of different support units 38, 40, 42, without having to use support units inserted as separate components between different parts of the exhaust gas heater.

[0029] In the exhaust gas heater 10 Figure 3In the partial illustration of the invention, the heating conductor device 18 includes a single heating conductor 14 disposed between the two carrier elements 20, 22 of the carrier device 24. This heating conductor is electrically and insulated with respect to the two carrier elements 20, 22 by carrier device support units 38, 40 provided in the form of an insulating coating. As will be described below, different design variations are shown here when the heating conductor 14 is supported with respect to the carrier element 20 and when it is supported with respect to the carrier element 22. These variations can be interchanged accordingly or implemented individually in each of the two support regions.

[0030] Carrier device support unit 38 in Figure 3 The illustrated example includes an insulating coating 50 applied to the carrier element 20. The insulating coating 50 may substantially cover the entire surface of the carrier element 20 facing the heating conductor 14, or it may cover only the area of ​​the carrier element 20 over which the carrier element 20 is supported. There is no fixed connection of the insulating coating 50 with respect to the heating conductor 14, thereby enabling relative movement, in principle, between the heating conductor 14 and the carrier element or the insulating coating 50 disposed on the carrier element, for example, due to heat or vibration. In a variation, the insulating coating 50 may substantially completely cover, for example, the heating conductor on the side of the heating conductor 14 facing the carrier element 20, or it may be disposed only in the area of ​​the heating conductor 14 that interacts with the support of the carrier element 20.

[0031] In the support path from the heating conductor 14 to the carrier element 22, the carrier device support unit 40 includes two insulating coatings 52 and 54. Insulating coating 52 is applied to the side of the heating conductor 14 facing the carrier element 22, while insulating coating 54 is applied to the side of the carrier element 22 facing the heating conductor 14. The insulating coatings 52 and 54 may also be configured to substantially completely cover the respective components bearing the insulating coating, i.e., the heating conductor 14 or the carrier element 22, or they may be provided only in the areas where the heating conductor 14 and the carrier element 22 support and interact with each other or begin to support and interact with each other.

[0032] To also achieve insulation of the connecting element 32 that holds the carrier device 24 together with the heating conductor device 18, the connecting element may be surrounded in the longitudinal region by a sleeve-shaped insulating element 48, such as an insulating element made of ceramic material, which extends through the connecting element opening 44 disposed in the heating conductor 14. To avoid interference between the insulating coatings 50, 52, or 54, the insulating coating may be interrupted in the heating conductor 14 where the connecting element opening 44 is formed, to provide space for accommodating the axially protruding portion of the corresponding insulating element 48 extending beyond the heating conductor 14.

[0033] Figure 4 This illustration shows a design in which the heating conductor device 18 includes two heating conductors 14 and 16 that are sequentially arranged along the longitudinal axis L of the exhaust gas heater. In the exhaust gas heater 10... Figure 4 In the illustrated design, the first carrier device support unit 38 disposed between the carrier element 20 and the heating conductor 14 also includes an insulating coating 50 applied to either the carrier element 20 or the heating conductor 14. Alternatively, the insulating coating may be applied to each element of the carrier element 20 and the heating conductor 14.

[0034] In this example, the heating conductor 16 is electrically insulated from the carrier element 22 by the two insulating coatings 52 and 54, wherein insulating coating 52 is applied to the heating conductor 16 and insulating coating 54 is applied to the carrier element 22. Alternatively, in this region, a single insulating coating may be applied, for example, to either the carrier element 22 or the heating conductor 16.

[0035] The heating conductor support unit 42, which provides electrical insulation and axial support for the two heating conductors 14, 16 about each other, includes an insulating coating 56 that can be applied to either the heating conductor 14 or the heating conductor 16. Alternatively, in this region, an insulating coating may also be applied to each of the heating conductors 14, 16, wherein, using the two insulating coatings, the two heating conductors 14, 16 are then axially supported against each other with electrical insulation about each other.

[0036] The rod portion 34 of each of the connecting elements 32 is surrounded in the longitudinal region by a sleeve-shaped insulating element 48, for example an insulating element made of ceramic material, and is therefore electrically insulated with respect to the heating conductors 14, 16 in this longitudinal region, which passes through the connecting element openings 44, 46 of the heating conductors 14, 16.

[0037] Insulating coatings 50, 52, 54, and 56 can be applied to the corresponding components, i.e., carrier elements 20 and 22 or heating conductors 14 and 16, using methods known in the art. For example, this application can be performed by vapor deposition. Alternatively, the structural material of insulating coatings 50, 52, 54, and 56 can be applied in a flowable state to the area to be coated on the surface of the relevant component and subsequently thermally and / or chemically cured. The insulating material can be, for example, a ceramic material, which on the one hand has relatively high mechanical stability, and on the other hand provides very good electrical insulation even when using relatively thin insulating coatings, especially under high heat resistance.

[0038] Because in the exhaust gas heater constructed according to the invention, not only electrical insulation but also axial support of the different components of the exhaust gas heater is achieved through an insulating coating, which accordingly has a fixed connection only with one of the components that support each other (i.e., the component where the insulating coating is applied), the relative mobility of the components with respect to each other is ensured in the components that support each other, thereby avoiding excessive mechanical load on the support unit provided by the coating. Nevertheless, by using high-temperature resistant construction materials, such as inorganic insulating materials based on ceramic substrates, mechanically stable electrical insulation can be provided even at high temperatures.

[0039] Because the insulating coatings 50, 52, 54, and 56 can be applied substantially to any surface area of ​​the component to be coated, it is also possible, for example, to coat the one or more heating conductors 14 and 16 in the areas of the respective connecting element openings 44 and 46, so as to also obtain electrical insulation with respect to the connecting element 32 passing through the connecting element openings 44 and 46 in this way and by this method. The insulating element 48, which also provides electrical insulation, can then be omitted, or a more cost-effective, non-electrically insulating sleeve, whose primary function is to radially center the connecting element 32 in the respective connecting element openings 44 and 46, can be used instead.

Claims

1. An exhaust gas heater for an exhaust system of an internal combustion engine, the exhaust gas heater comprising: Carrier device (24); A heating conductor device (18) supported on a carrier device (24) has at least one heating conductor (14, 16) through which current flows, said heating conductor being produced by separation from a flat material metal blank, wherein at least one heating conductor (14, 16) is electrically insulated from the carrier device (24) along the longitudinal axis (L) of the exhaust gas heater extending in the direction of the main exhaust gas flow (H) by at least one carrier device support unit (38, 40), or / and at least one heating conductor is electrically insulated from another heating conductor along the longitudinal axis (L) of the exhaust gas heater by a heating conductor support unit (42); Multiple connecting elements (32), wherein the heating conductor device (18) is connected to the carrier device (24) by means of the multiple connecting elements (32), The feature is that at least one carrier device support unit (38, 40) includes an insulating coating (50, 54) applied to the carrier device (24) and / or an insulating coating (52) applied to the heating conductors (14, 16) supported on the carrier device (24) by the carrier device support unit (38, 40); or / and at least one heating conductor support unit (42) includes an insulating coating (56) applied to one of the heating conductors (14, 16) supported by the heating conductor support unit (42) with respect to each other and / or an insulating coating applied to the other heating conductor (14, 16) supported by the heating conductor support unit (42), and At least one connecting element (32) is bolt-shaped and passes through at least one heating conductor (14, 16) of the heating conductor device (18) along the longitudinal axis (L) of the exhaust gas heater in the region of the connecting element opening (44, 46), and At least one bolt-shaped connecting element (32) is surrounded by an insulating element (48) in the longitudinal region through the opening (44, 46) of the connecting element.

2. The waste gas heater according to claim 1, characterized in that, The insulating element (48) is configured as an insulating material sleeve.

3. The waste gas heater according to claim 2, characterized in that, The insulating sleeve is made of ceramic material.

4. The waste gas heater according to any one of claims 1 to 3, characterized in that, At least one insulating coating is applied in a flowable state by deposition or coating.

5. The waste gas heater according to claim 4, characterized in that, Each insulating coating is applied in a flowable state by deposition or coating.

6. The waste gas heater according to any one of claims 1 to 3, characterized in that, At least one insulating coating is made of inorganic insulating material.

7. The waste gas heater according to claim 6, characterized in that, Each insulating coating is made of inorganic insulating materials.

8. The waste gas heater according to claim 6, characterized in that, At least one insulating coating is made of ceramic material.

9. The waste gas heater according to any one of claims 1 to 3, characterized in that, The carrier device (24) includes two carrier elements (20, 22) that house the heating conductor device (18) between themselves along the longitudinal axis (L) of the exhaust gas heater; and at least one carrier device support unit (38, 40) includes an insulating coating (50, 54) applied to one of the carrier elements (20, 22).

10. The waste gas heater according to claim 9, characterized in that, Each carrier device support unit (38, 40) includes an insulating coating (50, 54) applied to one of the carrier elements (20, 22).

11. The waste gas heater according to any one of claims 1 to 3, characterized in that, At least one carrier device support unit (38, 40) includes an insulating coating (52) applied to a heating conductor (14, 16) of the heating conductor device (18).

12. The waste gas heater according to claim 11, characterized in that, Each carrier device support unit (38, 40) includes an insulating coating (52) applied to one of the heating conductors (14, 16) of the heating conductor device (18).

13. The waste gas heater according to any one of claims 1 to 3, characterized in that, Each connecting element (32) passes through at least one heating conductor (14, 16) of the heating conductor device (18) in the region of the connecting element opening (44, 46) and is surrounded by an insulating element (48) in the longitudinal region of its passage through the connecting element opening (44, 46).

14. The waste gas heater according to any one of claims 1 to 3, characterized in that, At least one connecting element (32) passes through each heating conductor (14, 16) of the heating conductor device (18) in the region of the connecting element opening (44, 46) and is surrounded by an insulating element (48) in the longitudinal region of its passage through the connecting element opening (44, 46).

15. The waste gas heater according to any one of claims 1 to 3, characterized in that, Each connecting element (32) passes through each heating conductor (14, 16) of the heating conductor device (18) in the region of the connecting element opening (44, 46), and each connecting element is surrounded by an insulating element (48) in the longitudinal region of its passage through the connecting element opening (44, 46).

16. An exhaust system for an internal combustion engine, the exhaust system comprising at least one exhaust gas heater (10) according to any one of claims 1 to 15.

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