Heating device

Abstract

Heating device for an exhaust system of an internal combustion engine, comprising a support arrangement (18) and at least one heating conductor element (20) mounted on the support arrangement (18) so that gas can flow through it in the direction of a heating device longitudinal axis (L), wherein the support arrangement (18) comprises a first support element (37) arranged on a first axial side of the at least one heating conductor element (20), a second support element (41) arranged on a second axial side of the at least one heating conductor element (20) and a support element connection area (44) connecting the first support element (37) with the second support element (41) and extending radially outward and axially overlapping the at least one heating conductor element,wherein a first electrically insulating bearing material (47) is arranged between the first support element (37) and the at least one heating conductor element (20), and a second electrically insulating bearing material (48) is arranged between the second support element (41) and the at least one heating conductor element (20), characterized in that the first support element (37) extends radially within the first bearing material (47) axially towards the first axial side of the at least one heating conductor element (20), and / or that the second support element (41) extends radially within the second bearing material (48) axially towards the second axial side of the at least one heating conductor element (20).

Description

[0001] The present invention relates to a heating device for an exhaust system of an internal combustion engine according to the preamble of claim 1.

[0002] Such heating devices are used in exhaust systems to warm the gas flowing within the system, for example, the exhaust gas emitted by an internal combustion engine. Particularly during the start-up phase of an internal combustion engine's operation, when the exhaust gas has a comparatively low temperature, the heat absorbed by the heating device in the exhaust gas can be transferred to a downstream exhaust gas treatment system, such as a catalytic converter or particulate filter. This allows for rapid heating of the exhaust gas treatment system and significantly reduces the time during which exhaust gas is released into the environment without undergoing a cleaning process, such as a catalytic one.

[0003] From US Patent 5,597,503 A, a heating device according to the preamble of claim 1 is known, in which a substantially disc-shaped heating conductor element comprises a plurality of substantially parallel, elongated heating conductor sections. In one of their longitudinal end regions, the heating conductor sections connect to an adjacent heating conductor section in a heating conductor connection region. In the other of their longitudinal end regions, the heating conductor sections connect to another heating conductor section in a heating conductor section connection region, so that a substantially meandering structure of the heating conductor sections is generally obtained.The last two heating conductor sections of this meandering structure each provide a heating conductor element connection area, in which a contact element penetrating a housing-like exhaust gas guide element connects to the respective heating conductor element connection area and thus establishes an electrical connection with a voltage source.

[0004] The disc-shaped heating element is supported in its radially outer region by a support arrangement, which is generally designed with a ring-like structure. This support arrangement includes an upstream support ring on the upstream side of the heating element, which radially overlaps the heating element in its radially outer region. On the downstream side of the at least one heating element, a downstream support ring of the support arrangement is arranged, radially overlapping the heating element in its radially outer region. The two support rings are rigidly connected to each other by a support ring connection area formed by the exhaust gas routing component. Bearing material is arranged between the support rings and the radially outer region of the heating element, and also between the radially outer region of the heating element and the support ring connection area. This bearing material electrically insulates the heating element and holds it to the support arrangement.

[0005] From DE 10 2020 123 376 A1 a heating device is known in which ring-shaped insulating elements are positioned between the radially outer region of a heating conductor element and radially outer regions of the heating conductor element between receiving, disk-like support elements of a support arrangement.

[0006] DE 10 2008 040 476 A1 discloses a tubular component of an exhaust system. The tubular component is double-walled, consisting of an inner and an outer pipe. An insulating material is arranged between the inner and outer pipes. In the area of ​​an opening formed in the tubular component, a surrounding edge region of the outer pipe, covering the insulating material on its end face facing the opening, is drawn from the outside inwards into the opening.

[0007] EP 0 722 040 A2 discloses a double-walled component of an exhaust system. An insulating material is arranged between an inner pipe and an outer pipe. In the area of ​​an opening formed in the component, a surrounding edge region of the inner pipe, covering the insulating material on its end face facing the opening, is drawn into the opening from the inside out.

[0008] The object of the present invention is to provide a heating device for an exhaust system of an internal combustion engine, in which the at least one heating element mounted on the support arrangement is held in a defined position and protected.

[0009] According to the invention, this problem is solved by a heating device for an exhaust system of an internal combustion engine, comprising a support arrangement and at least one heating conductor element mounted on the support arrangement so that gas can flow through it in the direction of a heating device longitudinal axis, wherein the support arrangement comprises a first support element arranged on a first axial side of the at least one heating conductor element, a second support element arranged on a second axial side of the at least one heating conductor element and a support element connection area connecting the first support element to the second support element and radially overlapping the at least one heating conductor element axially on the outside.wherein a first electrically insulating bearing material is arranged between the first support element and the at least one heating conductor element, and a second electrically insulating bearing material is arranged between the second support element and the at least one heating conductor element.

[0010] The heating device is characterized in that the first support element radially overlaps the first bearing material in the direction of the first axial side of the at least one heating conductor element, or / and that the second support element radially overlaps the second bearing material in the direction of the second axial side of the at least one heating conductor element.

[0011] The axial overlap ensures that displacement of the bearing material, leading to undefined bearing effects, cannot occur. Simultaneously, the bearing material is protected against external influences on its radially inner side, particularly in the phase prior to integrating such a heating device into an exhaust system.

[0012] In order to avoid impairing the flow through the heating device while maintaining a defined support effect, it is proposed that the support arrangement be arranged in a ring-like manner around the at least one heating conductor element in a radially outer area.

[0013] For a stable structure, the first support element can comprise a first support ring that essentially completely surrounds the longitudinal axis of the heating device, and the second support element can comprise a second support ring that essentially completely surrounds the longitudinal axis of the heating device.

[0014] In a design that particularly allows for the simple electrical contacting of the at least one heating conductor element and also facilitates the assembly of the support arrangement, it is proposed that the support element connection area comprises a plurality of support element connection sections arranged at a distance from each other in the circumferential direction.

[0015] The design can be further simplified by forming the support element connection area integrally with at least one of the support elements, preferably the first support element. It should be noted that, in the context of the present invention, "integrally" means that the support element connection area is provided as a single component with the support element in question, constructed from a single block of material, and is not assembled from different components through assembly processes.

[0016] For the defined interaction with the bearing material, the first support element can comprise a substantially radially extending first support element body, wherein a first axial projection extending axially beyond the first bearing material is provided at a radially inner end region of the first support element body, and / or the second support element can comprise a substantially radially extending second support element body, wherein a second axial projection extending axially beyond the second bearing material is provided at a radially inner end region of the second support element body.

[0017] A simple structure can be achieved by forming the first axial element in one piece with the first support element body, or / and by forming the second axial element in one piece with the second support element body.

[0018] In order to extensively cover the bearing material on its radially inner side, it is proposed that the first axial projection substantially completely surrounds the heating device longitudinal axis, or / and that the second axial projection substantially completely surrounds the heating device longitudinal axis.

[0019] To avoid a constraint on the at least one heating conductor element in the support arrangement and also to avoid an electrical short circuit between the support arrangement and the at least one heating conductor element, it can be provided that the first support element does not completely overlap the first bearing material radially inside axially, and / or that the second support element does not completely overlap the second bearing material radially inside axially.

[0020] In a design that is easy and inexpensive to manufacture and also corrosion-resistant, the first support element can be designed as a sheet metal forming part and / or the second support element can be designed as a sheet metal forming part.

[0021] For a fixed connection of the two support elements, the support element connection area of ​​one of the support elements can overlap radially on the outside axially and be connected to the other support element by material bonding, preferably welding or brazing.

[0022] In order to provide a defined support effect for the at least one heating element over its entire circumference by means of the bearing material, it is proposed that the first bearing material comprises a first bearing material ring that essentially completely surrounds the longitudinal axis of the heating device, or / and that the second bearing material comprises a second bearing material ring that essentially completely surrounds the longitudinal axis of the heating device.

[0023] The first bearing material can, for example, be composed of preferably ceramic fiber material. Similarly, the second bearing material can, for example, be composed of preferably ceramic fiber material.

[0024] The invention further relates to an exhaust system for an internal combustion engine, comprising an exhaust gas routing component through which exhaust gas flows in a main exhaust gas flow direction, wherein an exhaust gas treatment arrangement is located in the exhaust gas routing component and at least one heating device constructed according to the invention is located upstream of the exhaust gas treatment arrangement.

[0025] The present invention is described in detail below with reference to the accompanying figures. These show: Fig. 1. A perspective view of a heating device for an exhaust system, viewed from an inflow side; Fig. 2 a detailed longitudinal section view of the heating device of the Fig. 1; Fig. 3 An axial view of a disc-shaped heating conductor element of the heating device of the Fig. 1; Fig. 4 Another detailed sectional view of the heating device Fig. 1; Fig. 5 a perspective view of the heating device of the Fig. 1, viewed from an outflow side; Fig. 6 A schematic representation of an exhaust system with a heating device and an exhaust gas treatment arrangement downstream of the heating device.

[0026] The figures show a heating device for a Fig. Figure 6 shows a schematic representation of the exhaust system 10 of an internal combustion engine, generally designated by 12. The heating device 12 is arranged in the exhaust system 10 in an exhaust gas routing component 14, for example, a pipe-like or housing-like component, in the main exhaust gas flow direction A upstream with respect to an exhaust gas treatment arrangement generally designated by 16. The exhaust gas treatment arrangement 16 can, for example, comprise a catalyst unit, such as an SCR catalyst, a particulate filter unit, or the like. In such an exhaust gas treatment arrangement 16, the exhaust gas flowing towards the heating device 12 and the exhaust gas treatment arrangement 16 in the main exhaust gas flow direction A is cleaned of pollutants contained therein, for example, in a catalytic reaction.

[0027] The heating device 12 comprises a support arrangement, generally designated 18, which surrounds a heating device longitudinal axis L in a ring-like manner. A [missing information] is attached to the support arrangement 18. Fig. Figure 3 shows the heating element 20 in axial view, mounted such that exhaust gas flowing in the main exhaust gas flow direction A or in the direction of the heating device's longitudinal axis L can pass through it. The heating element 20 is cut from an electrically conductive flat material, for example by laser cutting or the like, and has a fundamentally disc-like structure.

[0028] The heating conductor element 20 has a plurality of heating conductor sections 22 extending essentially parallel to one another, between which gap-like spaces 24 are formed through which the exhaust gas can flow. In their longitudinal end regions, the heating conductor sections 22 connect to one another in respective heating conductor section connection regions 26, which are integrally formed with them, resulting in a generally meandering structure of the adjacent heating conductor sections 22.

[0029] The heating conductor sections 28, 30, located at the ends of this meandering structure, connect to an adjacent heating conductor section 22 only at one of their longitudinal end regions in a heating conductor section connection area 26, and each provides a heating conductor section connection area 32, 34. In the heating conductor element connection areas 32, 34, the heating conductor element 20, which is heated when an electric current is applied to it, is connected to a voltage source in a vehicle, for example the vehicle's electrical system or a battery, via connection elements 50, 52 and contact elements 86, 88 of a feedthrough 84.

[0030] The carrier arrangement 18 comprises a Fig. 1. A first support element 37, recognizable at the front and, in the illustrated embodiment, providing an upstream first support ring 36, which attaches the heating conductor element 20 to its Fig.The frontally visible upstream side 38 is covered in its radially outer region. The support arrangement 18 further comprises a second support element 41 providing a downstream second support ring 40, which overlaps the heating conductor element 20 on its downstream side 42 in its radially outer region. For connecting the two support elements 37, 41, a support element connection area, generally designated 44, is provided on the first support element 37, which provides the upstream first support ring 36. This connection area comprises a plurality of support element connection sections 46, spaced apart from one another and extending substantially axially, which overlap the downstream second support ring 40 or the second support element 41 radially outwards in the axial direction and are firmly connected to it, for example, by welding or soldering.The two support elements 37, 41 can be formed, for example, by punching out and forming a respective sheet metal blank.

[0031] For the stable and electrically insulated mounting of the heating element 20 between the two support elements 37, 41, a first bearing material 47 or a second bearing material 48 is arranged between the radially outer region of the heating element 20 and each of the support elements 37, 41. This bearing material is provided, for example, by a first bearing material ring 49 or a second bearing material ring 51, respectively, and extends, for example, along the entire edge region of the heating element 20. The bearing material 47, 48 can, for example, be made of electrically insulating fiber material, such as ceramic material like silicon dioxide or aluminum oxide, and is held under axial preload between each of the support elements 37, 41 and the upstream side 38 or the downstream side 42 of the heating element 20, respectively.

[0032] The support elements 37, 41, designed as support rings 36, 40 in the illustrated embodiment, are constructed with a first support element body 54 and a second support element body 56, respectively, extending essentially radially and circumferentially. Radially on the outside of the first support element body 54, the support element connecting sections 46, which are integrally formed with it (i.e., formed in one piece), are attached. These connecting sections overlap the second support element body 54 of the second support element 41 radially on the outside and are firmly connected to it. Radially on the inside of each of the two support element bodies 54, 56, an axial projection 58, 60 extending towards the heating conductor element 20 is attached. The first axial projection 58 of the first support element 37 overlaps or...The first bearing material 47 partially overlaps axially on its radial inner side, so that a gap-like space 62 is formed between the first axial projection 58 and the upstream side 38 of the heating conductor element 20. Similarly, the second axial projection 60 of the second support element 41 partially overlaps axially on its radial inner side the second bearing material 48, so that a gap-like space 64 is formed between the second axial projection 60 and the downstream side 42 of the heating conductor element 20.

[0033] The two axial projections 58, 60 are integrally formed with their respective support element bodies 54, 56 by bending the latter at its radially inner end region and ensure a defined positioning of the first bearing material 47 and the second bearing material 48 relative to the heating conductor element 20. Simultaneously, the two axial projections 58, 60 shield the first bearing material 47 and the second bearing material 48 radially inwards and protect them from external influences, particularly before the heating device 10 is installed in an exhaust system. The gap-like spaces 62, 64 nevertheless ensure that an electrical short circuit cannot occur between the heating conductor element 20, through which current flows during heating operation, and the support arrangement 18.

[0034] It should be noted that in the heating device, the support elements positioned axially on both sides of the at least one heating conductor element do not necessarily have to have the continuous ring structure shown in the figures. For example, the support elements can also be provided by several support element sections arranged successively in the circumferential direction, spaced apart from one another, and thus forming a ring-like shape in their entirety, with an axial projection being formed on at least some of the support element sections. Furthermore, in the heating device shown in the figures, for example, more than one heating conductor element may be provided, and the single or possibly several heating conductor elements may have a differently wound path, for example, a spirally wound path of the respective heating conductor sections.

Claims

[1] Heating device for an exhaust system of an internal combustion engine, comprising a support arrangement (18) and at least one heating conductor element (20) supported on the support arrangement (18) so that gas can flow through it in the direction of a heating device longitudinal axis (L), wherein the support arrangement (18) comprises a first support element (37) arranged on a first axial side of the at least one heating conductor element (20), a second support element (41) arranged on a second axial side of the at least one heating conductor element (20) and a support element connection area (44) connecting the first support element (37) with the second support element (41) and extending radially outward and axially overlapping the at least one heating conductor element,wherein a first electrically insulating bearing material (47) is arranged between the first support element (37) and the at least one heating conductor element (20) and a second electrically insulating bearing material (48) is arranged between the second support element (41) and the at least one heating conductor element (20), characterized by , that the first support element (37) radially overlaps the first bearing material (47) axially within the first bearing material (47) in the direction of the first axial side of the at least one heating conductor element (20), or / and that the second support element (41) radially overlaps the second bearing material (40) axially within the second bearing material (48) in the direction of the second axial side of the at least one heating conductor element (20). [2] Heating device according to claim 1, characterized by , that the support arrangement (18) is arranged in a ring-like manner to surround the at least one heating conductor element (20) in a radially outer area. [3] Heating device according to claim 1 or 2, characterized by , that the first support element (37) comprises a first support ring (36) substantially completely surrounding the longitudinal axis (L) of the heating device, or / and that the second support element (41) comprises a second support ring (40) substantially completely surrounding the longitudinal axis (L) of the heating device. [4] Heating device according to one of claims 1-3, characterized by , that the support element connection area (44) comprises a plurality of support element connection sections (46) arranged at intervals from each other in the circumferential direction. [5] Heating device according to one of claims 1-4, characterized by , that the support element connection area (44) is formed integrally with at least one of the support elements (37, 41), preferably the first support element (37). [6] Heating device according to one of claims 1-5, characterized by, that the first support element (37) comprises a substantially radially extending first support element body (54), wherein a first axial projection (58) extending axially beyond the first bearing material (47) is provided at a radially inner end region of the first support element body (54), or / and that the second support element (41) comprises a substantially radially extending second support element body (56), wherein a second axial projection (60) extending axially beyond the second bearing material (48) is provided at a radially inner end region of the second support element body (56). [7] Heating device according to claim 6, characterized by , that the first axial projection (58) is formed in one piece with the first support element body (54), or / and that the second axial projection (60) is formed in one piece with the second support element body (56). [8] Heating device according to claim 3 and claim 6 or 7, characterized by, that the first axial projection (58) substantially completely surrounds the heating device longitudinal axis (L), or / and that the second axial projection (60) substantially completely surrounds the heating device longitudinal axis (L). [9] Heating device according to one of claims 1-8, characterized by that the first support element (37) does not fully overlap the first bearing material (47) radially inside axially, or / and that the second support element (41) does not fully overlap the second bearing material (48) radially inside axially. [10] Heating device according to one of claims 1-9, characterized by , that the first support element (37) is designed as a sheet metal forming part, or / and that the second support element (41) is designed as a sheet metal forming part. [11] Heating device according to one of claims 1-10, characterized by, that the support element connection area (44) of one of the support elements (37, 41) overlaps radially outside axially and is connected to the other support element (37, 41) by material connection, preferably by welding or brazing. [12] Heating device according to one of claims 1-11, characterized by , that the first bearing material (47) comprises a first bearing material ring (49) substantially completely surrounding the heating device longitudinal axis (L), or / and that the second bearing material (48) comprises a second bearing material ring (51) substantially completely surrounding the heating device longitudinal axis (L). [13] Heating device according to one of claims 1-12, characterized by , that the first bearing material (47) is composed of preferably ceramic fiber material, or / and that the second bearing material (48) is composed of preferably ceramic fiber material. [14] Exhaust system for an internal combustion engine, comprising an exhaust gas routing component (14) through which exhaust gas flows in a main exhaust gas flow direction (A), wherein an exhaust gas treatment arrangement (16) is arranged in the exhaust gas routing component (14) and at least one heating device (12) according to one of the preceding claims is arranged upstream of the exhaust gas treatment arrangement (16).

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