Heating element having an integrated electrode
Patent Information
- Application Number
- EP2023762377
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-25
- Filing Date
- 2023-08-24
- Publication Date
- 2025-05-21
AI Technical Summary
Existing heating elements for exhaust pipes face issues with vibrations causing noise and the risk of short circuits due to the proximity of heating loops and electrodes, which existing designs fail to adequately address.
The integration of spacer elements between heating loop sections, which are electrically insulated, either as part of the electrode connection element or separate components, ensures electrical isolation and prevents short circuits, while also providing structural support to maintain distance and reduce resonance-induced noise.
This design effectively prevents short circuits and noise from resonance vibrations, ensuring reliable operation by maintaining electrical insulation between heating loops and electrodes, thereby enhancing the durability and performance of the heating element.
Smart Images
Figure 1.1
Abstract
Description
[0001] Heating element with integrated electrode
[0002] The invention relates to a heating element for insertion into an exhaust pipe, comprising a heating resistor and two electrodes. The heating resistor has two contact zones, each electrode having an electrode connection element with a contact surface that is electrically connected to the respective contact zone of the heating resistor. The heating resistor is formed in a shape with a plurality of adjacently arranged heating loops that form a basic shape G with a central axis, or the heating resistor has a basic shape G with a central axis in which a plurality of adjacently arranged heating loops are formed, each heating loop being formed from two sections. Thus, at least two or, as a rule, a plurality of adjacently arranged sections are formed.The heating resistor forms a heater with the heating loops for heating the exhaust gas, whereby the heating resistor preferably has the contact zones at the end.
[0003] A heating element with electrodes for insertion into an exhaust pipe is already known from US Pat. Nos. 5,614,155 A and 5,888,456 A. The one-piece heating element has a contact zone at each end and is formed into several adjacent heating loops that form a circular basic shape with a central axis. Two electrodes are also provided, which are electrically connected to the respective contact zone via an electrode connection element.
[0004] From US 5,501,842 A a heating element with heating loops is known in which the heating loops are kept at a distance from each other by spacer elements.
[0005] DE 10 2022 116 755 A1 discloses a heating element with spacer element bridges, which are used in addition to the actual electrical connections. In contrast, DE 10 2021 131 364 A1 describes the use of a partially circumferential connection electrode that is in contact with the heating element at its end.
[0006] The invention is based on the object of designing and arranging a heating element with electrodes in such a way that vibrations and short circuits within the heating element are avoided.
[0007] The object is achieved according to the invention in that spacer elements are provided which are positioned between adjacent sections of the heating loop or between adjacent sections of the heating loops, wherein the respective spacer element and the respective heating loop are electrically insulated from one another, wherein a) the spacer elements are an integral or one-piece component of the respective electrode connection element, wherein the respective electrode connection element has at least two spacer elements or b) the spacer elements form a plurality of separate components, wherein the electrode connection element can be placed against the spacer elements without short-circuiting or c) at least some of the spacer elements are designed in the form of a one-piece spacer element bridge, wherein the electrode connection element can be placed against the spacer element bridge without short-circuiting.
[0008] In case a), when the spacer elements are an integral or one-piece component of the respective electrode connection element, the electrode connection element has an insulating layer that ensures electrical insulation from the heating resistor. Alternatively, the heating resistor can also have the insulating layer.
[0009] In case b), when the spacer elements form several separate components, the spacer elements are preferably made of an insulating material or a non-electrically conductive material such as ceramic, so that the respective spacer element and the respective heating loop are electrically insulated from each other. The electrode connection element is formed separately. It rests against the respective spacer element.
[0010] In case c), if at least some of the spacer elements are designed in the form of a one-piece spacer element bridge, the spacer element bridge is preferably formed from an insulating material or a non-electrically conductive material, such as ceramic or ceramic fibers, so that the respective spacer element and the respective heating loop are electrically insulated from one another.
[0011] In all three cases, adjacent heating loops are also electrically insulated from each other by the respective spacer element. The respective spacer element ensures only the distance between heating loops, only the distance between the electrode connection element and the heating resistor, or both distances.
[0012] This ensures that no noise occurs during operation of the heating element, particularly due to resonance vibrations of the heating resistor or heating loops. Furthermore, a short circuit between the respective electrode connection element and the heating resistor or heating loops is prevented.
[0013] The electrode and the electrode connection element can be designed as a single piece or as a two-piece assembly. It is also possible for the electrode, the electrode connection element, and the heating disc to be designed as a single piece.
[0014] It can also be advantageous for the electrode connection element to have an inner side facing the heating resistor and a front side, with an insulating layer being provided on the inner side that rests against the heating resistor, and with the contact surface being provided optionally on the front side. The electrode connection element with the integral spacer elements is insulated from the heating resistor by the insulating layer on the inner side. By placing the contact surface optionally on the front side, a spatial separation of the two functional surfaces, i.e. the insulating surface and the contact surface, is possible. The contact surface of the electrode connection element can in principle be placed on the inner side and / or the back side. The contact zone of the heating resistor can in principle be placed on the peripheral edge, the front side and / or the back side of the heating resistor.
[0015] Furthermore, it may be advantageous if the heating resistor has a surface, wherein at least some of the spacer elements protrude beyond the surface of the heating resistor by a distance m, wherein the electrode connection element can be placed against the protruding part of the respective spacer element without short circuits. At least some of the spacer elements protrude relative to the surface of the heating resistor in the area between the heating resistor and the electrode connection element. This enables the electrode connection element to be placed against the respective spacer element without short circuits.
[0016] It can also be advantageous if adjacent sections or heating loops define a groove with a central axis that serves to accommodate a spacer element, with a stop being provided against which the respective spacer element can be placed in the direction of the central axis. The stop is in contact at least when the spacer element is loaded by the electrode connection element and experiences a force directed toward the central axis. The groove or the central axis can be curved, for example, in an S-shape.
[0017] In this case, it can advantageously be provided that the heating resistor has an even number a of groove pairs in the area of the electrode connection elements, which pairs are occupied by spacer elements. A number a of four, six, or eight grooves is advantageous. This means that the required spacer elements of the number a can be distributed between two electrode connection elements or between two spacer element bridges. Both electrode connection elements or both spacer element bridges can thus be designed as identical parts. The one electrode connection element or the one spacer element bridge can thus be used for the left and right side. Opposite the electrode connection element, the heating resistor therefore has an odd number of grooves.
[0018] It may be advantageous for the present invention if the respective electrode connection element or the respective spacer element bridge has a number of a / 2 spacer elements. Thus, two identical electrode connection elements or two identical spacer element bridges can be used.
[0019] In connection with the design and arrangement according to the invention, it can be advantageous if the heating resistor has an axis of symmetry arranged at right angles to the central axis, wherein the heating resistor has a folding symmetry with respect to the two contact zones, wherein both electrode connection elements or both spacer element bridges are of identical design and can be used for both contact zones. With folding symmetry, both contact zones are mapped to one another when folded by 180° around the axis of symmetry. Thus, the two electrode connection elements or the two spacer element bridges can be identical components. The contact zone can in principle be located on the peripheral edge, the front side, and / or the back side of the heating resistor or the heating disc.
[0020] It may also be advantageous if the electrical insulation is formed as an insulating layer with a thickness between 0.5 mm and 3.0 mm. Alternatively, an insulating coating with a thickness of approximately 200 μm to 300 μm is also possible. The insulating layer or the insulating coating is preferably arranged on the electrode connection element or on the spacer element bridge.
[0021] Furthermore, it may be advantageous if the electrode connection element is made of a Ni-Cr-Mo alloy or an Fe-Cr-Al alloy or another high-temperature-resistant steel. Thus, the electrode connection element is temperature- and corrosion-resistant.
[0022] Furthermore, it can be advantageous if the electrode connection element is designed as a cast or sintered part. This makes manufacturing very cost-effective, especially when there is folding symmetry and two identical electrode connection elements are used for the right and left sides. The electrode connection element can also be manufactured as a single piece with the electrode or with the electrode and the heating disk.
[0023] It may be advantageous if the heating resistor has a ceramic or metallic honeycomb structure, with the ceramic honeycomb structure having an electrically conductive coating and / or with the electrically conductive coating or metallic honeycomb structure having a catalytic coating. In addition to heating, the heating element can also achieve catalytic purification of the exhaust gas.
[0024] Finally, a system may be advantageous, consisting of a heating element as described above and at least part of an exhaust system in the form of an exhaust pipe, wherein the heating element is arranged inside the exhaust pipe and the electrodes are led outwards outside the exhaust pipe.
[0025] Further advantages and details of the invention are explained in the claims and the description, and illustrated in the figures. It shows:
[0026] Figure 1a shows a heating element in perspective view;
[0027] Figure 1 b an electrode connection element;
[0028] Figure 2 shows a radiator according to Figure 1 a;
[0029] Figure 3 shows an alternative embodiment of the heating element;
[0030] Figure 4 shows a further embodiment of the heating element;
[0031] Figure 4a shows the heating element according to Figure 4 mounted in an exhaust pipe;
[0032] Figure 5 shows a further embodiment of the heating element;
[0033] Figure 6 shows a further embodiment of the electrode connection element;
[0034] Figure 7 shows an alternative embodiment of the heating element; Figure 7a shows an alternative embodiment of the spacer element;
[0035] Figures 8a, 8b show different embodiments of the honeycomb structure.
[0036] A heating element 10 shown in Figure 1a comprises a heating element in the form of a heating resistor 1. The heating resistor 1 has a plurality of heating loops 1.3a to 1.3c, wherein the heating resistor 1 has a contact zone 1.1, 1.2 at each end, to which an electrode connection element 2.3, 2.4 is electrically connected. The respective electrode connection element 2.3, 2.4 is in turn provided with an electrode 2.1, 2.2 for connection to an on-board electrical system. Each heating loop 1.3a - 1.3c has two sections or legs 1.3, which are separated from one another by a groove 1.6. Adjacent heating loops 1.3a, 1.3b or their legs 1.3 are also separated from one another by a groove 1.6. In the end area of the groove 1.6, a spacer element 3a to 3c is provided, which ensures the distance between adjacent heating loops 1.3a, 1.3b.
[0037] According to the embodiment shown in Figure 1a, the respective spacer element 3a to 3c is an integral component of the respective electrode connection element 2.3, 2.4. Three spacer elements 3a to 3c are provided. To prevent a short circuit between adjacent heating loops 1.3a, 1.3b or adjacent legs 1.3, the respective electrode connection element 2.3, 2.4 has an insulating layer 2.8, which is provided in particular where the respective spacer element 3a to 3c or the electrode connection element 2.3, 2.4 makes contact with the heating resistor 1. However, the spacer elements 3a to 3c can also be made of an electrically insulating material, such as ceramic.
[0038] Opposite the heating electrodes 2.1, 2.2, a spacer 5 designed as a bridge is provided, which also has corresponding spacer elements arranged in the end region of the respective groove 1.6.
[0039] Figure 1b shows an electrode connection element 2.3 as used in the exemplary embodiment shown in Figure 1a. The electrode connection element 2.3 has an inner side 2.6 on which the three respective spacer elements 3a, 3b, 3c protrude. The insulation layer 2.8 is applied to this inner side. In addition, the electrode connection element 2.3 has a front side 2.7 adjacent to the inner side 2.6. The front side 2.7 adjacent to the inner side 2.6 is stepped in the end region, with at least part of this step forming the contact surface 2.5, which can be brought into electrical contact with the respective contact zone 1.1, 1.2 of the heating resistor 1.
[0040] Figure 2 shows the heating resistor 1 itself. The heating resistor 1 has a round basic shape_G, which ensures installation in a likewise round exhaust pipe 4 according to Figure 4a. The heating resistor 1 has an axis of symmetry 1.5, which is arranged at right angles to a central axis 1.4. The contact zone 1.1 is provided on the left side according to Figure 2, with the contact zone 1.2 being provided on the right side. With reference to the respective contact zone 1.1, 1.2, the heating resistor 1 has a folding symmetry K, so that the contact zone 1.1 can be transferred into the contact zone 1.2 by folding around the axis of symmetry 1.5. Due to this folding symmetry of the two contact zones 1.1, 1.2, it is possible to use two electrode connection elements 2.3 that are identical in terms of symmetry in order to electrically connect both the contact zone 1.1 and the contact zone 1.2 to the respective electrode 2.1, 2.2, as shown in Figure 1a.
[0041] The embodiment shown in Figure 3 differs from that shown in Figure 1a in that the folding symmetry of the two contact zones 1.1, 1.2 shown in Figure 2 is not present. According to the embodiment shown in Figure 3, two electrode connection elements 2.3, 2.4 are used. As in the embodiment shown in Figure 1a and Figure 2, each connection element 2.3, 2.4 has three spacer elements 3a to 3c, so that a total of six spacer elements are provided, each in one of the six grooves 1.6, which terminate at the end in the area of the electrodes 2.1, 2.2.
[0042] In contrast, the bridge 5 has seven spacer elements, thus an odd number of spacer elements for a corresponding number of grooves 1.6, which open at the lower end opposite the electrodes 2.1, 2.2. According to the embodiment in Figure 4, in contrast to Figure 3, the bridge 5 has an even number of spacer elements, here eight spacer elements, while in the upper area of the electrodes 2.1, 2.2, two electrode connection elements 2.3, 2.4 are provided, which have a total of five odd number of spacer elements. The left electrode connection element 2.3 has three spacer elements 3a to 3c, while the right electrode connection element 2.4 has only two spacer elements 3a, 3b. According to the embodiment shown in Figure 4, both electrode connection elements 2.3, 2.4 are different both with regard to the respective contact surface 2.5 and with regard to the number of spacer elements 3a to 3c.
[0043] According to the embodiment shown in Figure 4a, the heating element 10 is arranged or mounted within an exhaust pipe 4. The electrodes 2.1, 2.2 are led to the outside via the two electrode connection elements 2.3, 2.4.
[0044] According to the embodiment shown in Figure 5, the electrodes are at an angle of approximately 160° to each other. In contrast to the embodiment shown in Figure 4a, the two electrodes 2.1, 2.2 are provided at the opposite ends of the respective electrode connection elements 2.3, 2.4.
[0045] According to the exemplary embodiment in Figure 6, each electrode connection element 2.3, 2.4 has two spacer elements 3b, 3c, supplemented by a single spacer element 3a. The spacer element 3a is positioned separately from the two electrode connection elements 2.3, 2.4 in the central groove 1.6 and only ensures the distance between the heating loops 1.3a, 1.3b and the legs 1.3. In this way, despite the electrode connection elements 2.3, 2.4 being of identical design, an odd number of grooves 1.6 can be supplied with corresponding spacer elements 3a to 3c. In the left half of the figure, the spacer element bridge 3 is a one-piece or integral component of the electrode connection element 2.4. The insulation layer 2.8 is provided on the inner side 2.6 of the electrode connection element 2.3, as explained with reference to Figure 1a. According to the right half of Figure 6, an alternative to the electrode connection element 2.4, a spacer bridge 3 may be provided. The spacer bridge 3 is not a one-piece or integral part of the electrode connection element 2.4, but rather a separate component. The electrode connection element 2.4 is positioned adjacent to the spacer bridge 3. Alternatively, the insulation layer 2.8' can also be positioned on the side between the spacer bridge 3 and the electrode connection element 2.4.
[0046] According to the exemplary embodiment in Figure 7, three individual or separate spacer elements 3a to 3c are provided between the respective electrode connection element 2.3, 2.4 and the heating resistor 1. According to a detailed view of an end region of a groove 1.6 between two adjacent heating loops 1.3a, 1.3b or legs 1.3, it can be seen that the respective spacer element 3a - 3c protrudes by a dimension m from a surface 1a of the heating resistor 1. The respective electrode connection element 2.4 rests against the spacer element 3c from above, thus preventing contact between the electrode connection element 2.4 and the respective heating loop 1.3a, 1.3b. The groove 1.6 has a central axis 1.6a and a recess 1.6b that extends transversely to the central axis 1.6a. The groove 1.6 forms a stop 1.9 in the respective heating loop 1.3a, 1.3b, against which the spacer element 3c can be brought into contact in the direction of the central axis 1.6a.This ensures that the respective spacer element 3a to 3c rests against the heating resistor 1 or the respective heating loop 1.3a, 1.3b in the direction of the central axis 1.6a. The spacer element 3c only ensures the distance between the electrode connection element 2.4 and the heating resistor 1 without influencing the distance between the heating loops 1.3a. All spacer elements 3a - 3c are thus designed separately from the respective electrode connection element 2.3, 2.4 or separately from the spacer element bridge 3.
[0047] According to the embodiment shown in Figure 7a, the stop 1.9 is formed by the spacer element 3c itself. The spacer element 3c has a shoulder that bears against the surface 1a of the respective heating loop 1.3a, 1.3b or the leg 1.3 or the heating resistor 1. In the embodiment shown in Figures 8a, 8b, a honeycomb structure 11 of the heating resistor 1 is shown. According to Figure 8a, the honeycomb structure 11 is formed from ceramic material and has an electrically conductive coating 1.7. In the embodiment shown in Figure 8b, in addition to the electrical coating 1.7 or, in the case of a honeycomb structure made of metal, in addition to this honeycomb structure, a catalytic coating 1.8 for catalytically purifying the exhaust gas is provided.
[0048] List of reference symbols Heater, heating resistor a Surface .1 Contact zone .2 Contact zone .3a Heating loop .3b Heating loop .3c Heating loop .3 Section or leg of 1 ,3a-1 ,3c.4 Central axis .5 Axis of symmetry .6 Groove .6' Groove .6a Central axis .6b Recess .7 Electrical coating .8 Catalytic coating .9 Stop .1 Electrode .2 Electrode .3 Electrode connection element .4 Electrode connection element .5 Contact surface .6 Inside .7 Front .8 Insulation layer .8' Insulation layer Spacer bridge a Spacer b Spacer c Spacer Exhaust pipe 5 Spacer, bridge
[0049] 10 Heating element
[0050] 11 Honeycomb structure m dimension, overhang
[0051] G basic form
[0052] K Folding symmetry
Claims
Heating element (10) for insertion into an exhaust pipe (4) with a heating resistor (1) and with two electrodes (2.1, 2.2), wherein the heating resistor (1) has two contact zones (1.1, 1.2), wherein the respective electrode (2.1, 2.2) has an electrode connection element (2.3, 2.4) with a contact surface (2.5) which is electrically connected to the respective contact zone (1.1, 1.2) of the heating resistor (1), wherein the heating resistor (1) has a basic shape_G with a central axis (1.4), wherein one or more heating loops (1.3a, 1.3b, 1.3c) arranged next to one another are formed, wherein the respective heating loop (1.3a, 1.3b) is formed from two adjacent sections (1.3), characterized in that spacer elements (3a, 3b, 3c) are provided, which can be positioned between adjacent sections (1.3), wherein the respective spacer element (3a, 3b, 3c) and the respective heating loop (1.3a, 1.3b) are electrically insulated from one another, wherein a) the spacer elements (3a, 3b, 3c) are an integral or one-piece component of the respective electrode connection element (2.3, 2.4), wherein the respective electrode connection element (2.3, 2.4) has at least two spacer elements (3a, 3b, 3c) or b) the spacer elements (3a, 3b, 3c) form a plurality of separate components, wherein the electrode connection element (2.3, 2.4) can be placed against the spacer elements (3a, 3b, 3c) without short-circuiting or c) at least some of the spacer elements (3a, 3b, 3c) are designed in the form of a one-piece spacer element bridge (3), wherein the electrode connection element (2.3, 2.4) can be placed against the spacer element bridge (3) without short-circuiting. Heating element (10) according to claim 1a, characterized in that the electrode connection element (2.3, 2.4) has an inner side (2.6) facing the heating resistor (1) and a front side (2.7), wherein an insulating layer (2.8) is provided on the inner side (2.6), which layer rests against the heating resistor (1), and wherein the contact surface (2.5) is optionally provided on the front side (2.7). Heating element (10) according to claim 1b, characterized in that the heating resistor (1) has a surface (1a), wherein at least some of the spacer elements (3a, 3b, 3c) protrude beyond the surface (1a) of the heating resistor (1) by a dimension m, wherein the electrode connection element (2.3, 2.4) can be placed against the protruding part of the respective spacer element (3a, 3b, 3c) without causing a short circuit. Heating element (10) according to one of the preceding claims, characterized in that adjacent sections (1.3) have a groove (1.6) with a central axis (1, 6a) that serves to receive a spacer element (3a, 3b, 3c), wherein a stop (1.9) is provided against which the respective spacer element (3a, 3b, 3c) can be placed in the direction of the central axis (1.6a). Heating element (10) according to one of claims 1a, 1c, 2 or 4, characterized in that the heating resistor (1) has an even number a of grooves (1.6) in the region of the electrode connection elements (2.3, 2.4), which are occupied by spacer elements (3a, 3b, 3c). Heating element (10) according to claim 5, characterized in that the respective electrode connection element (2.3, 2.4) or the respective spacer element bridge (3) has a / 2 spacer elements (3a, 3b, 3c). Heating element (10) according to one of the preceding claims, characterized in that the heating resistor (1) has an axis of symmetry (1.5) arranged at right angles to the central axis (1.4), wherein the heating resistor (1) has a folding symmetry (K) with respect to the two contact zones (1.1, 1.2), wherein both electrode connection elements (2.3, 2.4) or both spacer element bridges (3) are of identical design and can be used for both contact zones (1.1, 1.2). Heating element (10) according to claim 7, characterized in that the electrical insulation is designed as an insulating layer (2.8) and has a thickness between 0.5 mm and 3.0 mm. Heating element (10) according to one of the preceding claims, characterized in that the electrode connection element (2.3, 2.4) is formed from a Ni-Cr-Mo alloy or an Fe-Cr-Al alloy. Heating element (10) according to one of the preceding claims, characterized in that the electrode connection element (2.3, 2.4) is formed as a cast or sintered part. Heating element (10) according to one of the preceding claims, characterized in that the heating resistor (1) has a ceramic or a metallic honeycomb structure (11), wherein the ceramic honeycomb structure (11) has an electrically conductive coating (1.7) and / or wherein the electrically conductive coating (1.7) or the metallic honeycomb structure (11) has a catalytic coating (1.8). System consisting of a heating element (10) according to one of the preceding claims and at least part of an exhaust system in the form of an exhaust pipe (4), wherein the heating element (10) is arranged within the exhaust pipe (4) and the electrodes (2.1, 2.2) are guided to the outside.