Supporting structure for heating disc or heating resistor, supporting system and electric waste gas heater

Abstract

The invention relates to a support structure (70) for a heating disc or a heating resistor (10) in an exhaust gas system, comprising: a housing (35) consisting of multiple parts; at least one first outer ring (40) made of fibrous material; and at least one second inner ring (80) made of a temperature-resistant material that is electrically non-conductive and is different from the fibrous material of the at least one first ring (40); wherein the at least one second inner ring (80) defines an accommodating space for the heating disc or the heating resistor (10).

Description

TECHNICAL FIELD

[0001] The present invention generally relates to support structures and systems for carrying heating elements, with particular application in the field of exhaust aftertreatment systems. BACKGROUND

[0002] In view of the upcoming emission regulations (e.g. Euro 7, CN 7, EU VII, CN VII), automobile manufacturers are constantly seeking technologies for active thermal management of exhaust aftertreatment systems, with a view to reducing cold start emissions while maintaining the operating temperature of the exhaust system-related components. In this context, electric exhaust heaters (also known as electric heaters or electric heating devices) are considered a very promising technology, not only to help achieve future emission targets, but also to actively extend the service life of the underlying system.

[0003] In this regard, a very promising application is the use of heating elements with a honeycomb structure (e.g. square or hexagonal), made of a high-temperature-resistant material (e.g. nickel-chromium or iron-chromium-aluminum alloy), which have very good heating properties and take up less installation space.

[0004] However, the integration of such heating elements into the metal housing of an exhaust aftertreatment system is a challenge, which mainly requires the following: The heating elements (e.g. heating discs or heating resistors) should be firmly fixed in the housing to meet the requirements during the entire service life of the vehicle, taking into account high exhaust gas temperatures and mass flows, as well as high values of axial and radial vibrations and accelerations. In addition, electrical insulation means should be provided to prevent short circuits or other malfunctions. Furthermore, it is necessary to thermally insulate the surrounding components and to simplify the manufacturing process as much as possible.

[0005] So far, the fixation of the heating discs has always used a pair of compression or pre-tightening rings, which are welded to the partition tube from both sides of the heating disc.

[0006] However, during internal tests on electric heaters manufactured in this way, it was found that the continuous operation of the thermoelectric leads to wear and erosion, especially with regard to the compression rings, which leads to a deterioration of the performance of the support structure and the superordinate support system and to damage to the electric heater itself, ultimately leading to failure. It is assumed that the wear is mainly caused by the relative movement between the heating disc and the compression ring. During the assembly of the electric heater, when the compression support means is tightened, certain parts of the ring are pressed into the honeycomb structure of the heating disc. During operation of the electric heater, these elements can break and gradually protrude from the metal ring of the housing as the heating disc expands and contracts.

[0007] In this context, please refer to US 2022 / 0186647 A1, which discloses a heating device and exhaust gas system with a stabilizing element. Furthermore, US 5597503 A shows an axially mounted electric heater housing for heating exhaust gas flow, the housing having a peripheral pressure ring capable of generating a diameter-balancing force. The heating element is mounted in a housing with an integral shell wall, wherein the heating element is secured by an annular support element and an annular pressure ring fixed to the shell wall. Additionally, US 6025578 A discloses an electrically insulating perforated part with an electro-corrosion protection device. Purpose of the invention

[0008] The purpose of this invention is to overcome one or more problems or disadvantages associated with the prior art. Summary of the Invention

[0009] The aforementioned objectives and other problems are solved by a support structure, support system, and electric exhaust gas heater as described in the main claim. The dependent claims relate to preferred embodiments of the invention.

[0010] This invention relates to a support structure for a heating plate or heating resistor in an exhaust gas system, comprising: a multi-part housing, at least one first outer ring made of a fibrous material, and at least one second inner ring made of a non-conductive material, the material of which differs from the fibrous material of the at least one first ring. The at least one second inner ring defines a receiving space for the heating plate or heating resistor. This arrangement of the support structure has the advantage of structurally separating the at least one first outer ring from the heating plate or heating resistor in the exhaust gas system. Such separation helps reduce wear on the support structure caused by thermal and / or mechanical stress during use in the exhaust gas system.

[0011] The support structure can optionally be designed such that at least one first ring is two rings, and / or at least one second ring is two rings, wherein the space for accommodating the heating plate or heating resistor is preferably defined between the two second rings. Depending on the specific application, this structure can simplify the assembly of the support structure and its installation in the superstructure.

[0012] In the support structure, the multi-part housing optionally has at least two metal rings or two metal halves, preferably configured to apply a predefined clamping pressure of up to about 15 bar to the first and second rings. Depending on the specific application and / or foundation mounting dimensions, this pressure is particularly preferably 2 to 4 bar. The above values ​​do not include general tolerances for the metal housing components and catalyst support ceramic fiber materials used in the manufacture of the exhaust system.

[0013] The fiber material of the first ring of the support structure, which is at least one ring, can be a ceramic material, preferably Al2O3, SiO2, or mullite ceramic material, wherein the latter is a mixture of Al2O3 and SiO2, more specifically, Al2Al 2+2x Si 2-2x O 10-x , where x = oxygen vacancies in each basic unit.

[0014] Furthermore, the fiber material of the first ring, which is at least one of the supporting structures, optionally has fibers with a diameter of about 3µm to 12µm, preferably 5µm to 10µm. Additionally, or alternatively, the fiber aspect ratio of the fiber material is greater than 3:1.

[0015] Furthermore, the support structure may optionally consist of at least one or two first rings that are compressible, and the compression coefficient is preferably in the range of 2 to 5 in the installed state.

[0016] Further, the material of at least one or two second rings optionally has at least one of the following characteristics: a maximum temperature resistance of 1100 °C, preferably in the temperature range of -40 °C to 1100 °C. Alternatively, it may be compressible, flexible, and / or bendable, wherein the compressibility is particularly preferably lower than that of the material of at least one first ring, and in a lower percentage range, particularly preferably a maximum of 20%. Further, or alternatively, it is malleable, preferably annular, oval, or elliptical. Furthermore, it may optionally possess properties such as resistance to erosion, resistance to exhaust gases, and / or chemical resistance, preferably resistance to substances that may be present in the exhaust gas aftertreatment system.

[0017] The material of at least one or two second rings of the supporting structure may be mica, internationally known as "Mica". Preferably, the material of at least one or two second rings of the supporting structure is layered silicate, particularly preferably titanic mica, muscovite, potassium magnesium aluminum silicate containing optional fluoride or hydroxide ions, non-organic binders, or combinations thereof. Here, the material can be selected according to the application: due to its high temperature resistance, titanic mica is particularly suitable for applications involving extremely high-temperature exhaust gases, such as gasoline applications or internal combustion engines. In contrast, muscovite is more suitable for lower-temperature environments, such as the temperature environments that may occur in diesel applications.

[0018] At least one first ring and / or second ring of the support structure may optionally consist of at least two parts in the circumferential direction. Depending on the specific application, installation space, and / or whether pre-assembly of the support structure is required, symmetrical division is preferred, for example, division every 180°. Alternatively, asymmetrical or uneven division may be used, wherein only one of the aforementioned rings may be divided once or multiple times. For example, a potential influencing factor in this regard is the number and / or arrangement of electrodes on the heating plate or heating resistor used. An independent influencing factor, and also a technical advantage, is that existing support systems can be modified to conform to the support structure according to the present invention by appropriately adjusting the division of the existing rings.

[0019] Alternatively, at least one first ring and / or second ring may optionally have an L-shaped, U-shaped, circular, or rectangular cross-section. Any combination of rings and cross-sections is included herein, which has a corresponding impact on aspects such as the installability or reconfigurability of the support structure according to the invention, as well as economic aspects (e.g., in terms of the availability of the basic raw materials used).

[0020] The support structure, consisting of at least one second ring or two second rings, may optionally exist as a coating on the corresponding side of at least one first ring or a corresponding first ring. Simultaneously, or alternatively, the thickness of the at least one second ring or two second rings may optionally be from about 0.1 mm to 1.5 mm, preferably from about 0.1 mm to 0.8 mm.

[0021] In addition, at least one of the second rings or at least one of the two second rings may optionally have a metal mesh insert.

[0022] In addition, the support structure may optionally have at least one first ring or at least two first rings having a continuous outer contour or alternating grooves and / or protrusions.

[0023] The present invention also relates to a support system for an electric heating device, comprising: a support structure according to the present invention and a heating plate or heating resistor, preferably double-sided, having a honeycomb structure and / or multiple slits. The heating plate or heating resistor is located within the receiving space of at least one second ring or between two second rings.

[0024] In the support structure or support system according to the present invention, the corresponding first ring and second ring are optionally pre-assembled, preferably glued or sewn together. Alternatively or simultaneously, heating plates or heating resistors are optionally pre-assembled on both sides with the corresponding sides of the corresponding second ring, preferably glued or sewn together. Therefore, in the assembled state, issues such as shape stability and assembly accuracy can be improved. Furthermore, the optional pre-assembly of individual components simplifies the assembly of the support structure or support system according to the present invention.

[0025] The support structure or support system may optionally have a plurality of pins for positioning, supporting, fixing the heating plate or heating resistor and / or providing electrical insulation between local areas of the heating plate or heating resistor (10), wherein the plurality of pins are preferably spacer elements, and particularly preferably, some of the spacer elements are designed as fixing devices located in corresponding grooves in the housing, wherein at least one end of the fixing device is directly mechanically connected to the housing; and / or at least some of the spacer elements are located between two second rings (80), preferably pre-tightened. The pins may optionally perform the function of electrical insulation between local areas of the heating plate (winding heating circuit).

[0026] Furthermore, the support system may optionally have at least one or two second rings that contact only the edge region of the heating plate or heating resistor in the circumferential direction, wherein the edge region is not actively heated. This bearing method of the heating plate or heating resistor also allows the heating plate or heating resistor to slide in the support system or be supported in a sliding seat during heating or cooling.

[0027] The present invention also relates to an electric exhaust gas heater having a support system according to the present invention and a heater housing, preferably made of metal, located in the exhaust gas duct of an exhaust gas aftertreatment system and provided for accommodating the support system. Attached Figure Description

[0028] The present invention, and its further details and advantages, will be described below with reference to preferred embodiments in the accompanying drawings, wherein like reference numerals denote like elements. Wherein: Figure 1 An isometric view of an electric exhaust gas heater with two electrodes; Figure 2 Partial cross-sectional side view and top view of an electric exhaust gas heater; Figure 3 According to Figure 2 A cross-sectional view of the electric exhaust gas heater drawn with section line AA in the middle, and a detail view B in the cross-sectional view; Figure 4 The component according to the invention, shown from different angles, consists of an L-shaped first ring and a flat second ring; Figure 5 According to Figure 2 A cross-sectional view of an electric exhaust gas heater drawn with the AA section line, and a detailed view of the cross-sectional view; Figure 6 Two views of the flat second ring according to the present invention; Figure 7 According to Figure 2 A cross-sectional view of an electric exhaust gas heater drawn with the AA section line, and a detailed view of the cross-section. Detailed Implementation

[0029] In this description, terms such as “above,” “below,” “right,” and “left,” as well as similar descriptions, refer to the orientation or arrangement shown in the figures and are used only to describe embodiments. These expressions may indicate a preferred arrangement but should not be construed as limiting.

[0030] Furthermore, expressions such as "basically", "approximately", and "roughly" imply that a deviation of + / -10% (preferably + / -5%) from the stated value is permissible.

[0031] The following describes the use of multiple rings, such as at least one first ring, at least one second ring, or a metal ring. The term "ring" is a general term for a type of element, which does not necessarily have to be circular. More precisely, it can be geometrically adjusted according to other structural parameters, and is still conceptually included, in particular considering the shape of the housing and / or the heating element used.

[0032] This specification describes the use or installation of the heating element in various embodiments of the invention, as illustrated in the accompanying drawings. The following features are equally applicable to all embodiments, even if they are only presented, shown, or specifically described, for example, in a circular and / or disc-shaped form.

[0033] Figure 1 An isometric view of electric exhaust gas heaters 1, 2, and 3 with two electrodes is shown. In this illustration, the heating element, more specifically the heating plate 10 and the multi-component heater housing, can also be seen from the outside; only the outer side 20 is visible here for the time being. The heating plate 10 has an exemplary configuration including multiple slits and two electrodes for power supply, which are preferably mounted on the heating plate 10, for example, directly by laser welding.

[0034] The heating element used in this invention, more specifically the heating plate or heating resistor, is preferably composed of a regular honeycomb or honeycomb structure, which has honeycomb with different shapes, such as square or hexagonal honeycombs; and / or is made of high-temperature resistant materials (e.g., nickel-chromium alloy or iron-chromium-aluminum alloy); and / or has very good heating performance while occupying little installation space. The heating element may have a circular cross-section and / or be disc-shaped.

[0035] The heating plate may have multiple slits, the width of which is preferably greater than 1 mm, and particularly preferably between 1 mm and 5 mm. Between the individual slits, 2 to 10, preferably 4 to 5, particularly preferably 3, or even only 2 honeycombs may be arranged side-by-side, wherein this number can vary depending on the specific application, the location of the multiple slits, and / or the required resistance. The width or aperture of each honeycomb may be selected between 1.2 mm and 1.3 mm, preferably 1.27 mm. Its wall thickness is in the range of 150 µm. In this invention, it is particularly preferred that the honeycomb structure used has a honeycomb density between 50 CPSI and 400 CPSI (CPSI = cells per square inch), i.e., 8 to 62 honeycombs per square centimeter. Depending on the arrangement of the individual slits on the heating plate, for example, interconnected honeycombs may be arranged into meandering heating loops, which are interconnected at their respective ends and located between adjacent slits. Such heating loops are particularly useful for preventing electrical short circuits.

[0036] According to the present invention, the heating plate used has sharp edges, such as circumferential sharp edges, due to manufacturing and / or shape reasons, depending on the honeycomb and adjacent slit structures. Preferred manufacturing processes belong to additive manufacturing, generative manufacturing, and rapid manufacturing technologies, hereinafter collectively referred to as 3D printing processes. However, the support structure, support system, and / or electric exhaust heater of the present invention are also compatible with heating plates or heating resistors produced by other manufacturers, which makes the present invention usable for retrofit systems as well. Examples of alternative manufacturing processes include extruded heating plates, heating plates made of welded, fused, or molded sheets, and cast or stamped heating plates. The thickness of the heating plate used in the present invention is preferably between 3 mm and 15 mm, particularly preferably between 4 mm and 8 mm, wherein other sizes may also be considered depending on the specific application.

[0037] Figure 2 The partial sectional side view and top view show the relationship with Figure 1 The electric exhaust gas heaters 1, 2, and 3 shown are basically identical in configuration. Figure 2In a partial cross-section of the electric exhaust gas heaters 1, 2, and 3 located in the upper right corner, a pin or bolt 60 embedded in the heating plate 10 is shown. This pin is one of a plurality of pins 60. The pin 60 is used to position, support, and / or secure the heating plate or heating resistor 10 within the housing of the supporting structure (not shown in detail here). The pin 60 is preferably a spacer element, which may have a metal core and preferably a ceramic coating, for maintaining spacing between local areas of the heating plate 10. Particularly preferred, at least a portion of the spacer element is designed as a fixing device located in a corresponding recess in the housing, wherein at least one end of the fixing device can be directly mechanically connected to the housing. Furthermore, they also function as spacers by maintaining a constant distance between the various parts of the overall structure, thereby preventing potential short circuits.

[0038] Below the cross-sectional view, the top view of the electric exhaust gas heaters 1, 2, and 3 again shows the outer side 20 of the heater housing and the cover plate 50 belonging to the heater housing. Combined with the internal structure (not shown here), a purely exemplary arrangement can be formed, which can be adjusted according to specific applications.

[0039] Figure 3 It shows that according to Figure 2 A cross-sectional view of the electric exhaust gas heater 1 drawn with section line AA in the middle, and a detail view B in the cross-sectional view. Figure 3 The electric exhaust gas heater 1 has a heating plate 10. In addition, due to factors such as installation space, assembly type and sequence of the overall structure, other housing components or corresponding partitions may be required.

[0040] Figure 3 The electric exhaust gas heater 1 has a support structure 70 for the heating plate 10 according to the invention, wherein the support structure 70 has the following elements: a multi-part housing 35, shown herein as a two-part form, preferably annular and / or made of metal. Figure 3 As shown, the shell 35, composed of multiple parts of the support structure 70, can be... Figure 1 The components of the heater housings of the electric exhaust gas heaters 1, 2, and 3 are shown. Accordingly, in Figure 3 In the middle, the inner side 30 of the heater housing coincides with one side of the housing 35 of the support structure 70.

[0041] Figure 3The support structure 70 also has two first outer rings 40 made of fibrous material and two second inner rings 80 made of a non-conductive material, different from the fibrous material of the first rings 40. Here, the two inner rings 80 define a receiving space for the heating plate 10. Within the receiving space of the support structure 70 of the electric exhaust gas heater 1, the heating plate 10 is located between the two second inner rings 80. The two second inner rings 80 are here implemented in a flattened manner. They, together with the heating plate 10, the two L-shaped outer rings 40, and the two-part housing 35, constitute the support system for the electric heating device according to the invention, including, for example, the heating plate 10. The support structure 70 clamps the heating plate 10 at its edge region, which is not actively heated.

[0042] Even if not Figure 3 In the detailed view of section B, in the support structure 70 or the support system, such as Figure 2 As described above, alternatively, multiple pins 60 may be installed at this location. One end of these pins 60 may optionally be located in a metal ring of the support structure 70, or as described above. Figure 3 As shown, the other end is pre-tightened between the second rings. In the axial direction, they are held in position by means of the first and second rings 40, 80. At the other end, they are clamped between the wire portion of the heating plate 10 and the second ring 80, and are in axial contact. The optional combination of the support structure 70 and the plurality of pins 60 according to the invention can synergistically improve the overall device's resistance to external influences. Only a few aspects, such as shape stability, wear resistance, and temperature resistance, are cited as examples here.

[0043] Figure 4 The assembly, shown from different angles, consists of an L-shaped first ring 40 and a flat second ring 80. To the right of the ring assembly, half of the housing space for the heating plate 10 is shown.

[0044] Figure 5 A cross-sectional view of the second electric exhaust gas heater 2 is shown, its basic configuration being similar to... Figure 1 Same, also based on Figure 2 The AA section view is drawn. In addition, there is a detailed view B derived from the section view.

[0045] Specifically Figure 5 The second electric exhaust gas heater 2 in Figure 3The difference between the first electric exhaust gas heater 1 and the second electric exhaust gas heater 2 lies in the different shape of the components of the support structure 70 for the heating plate 10. Firstly, the multi-part housing 35 is also a component of the heater housings 20, 30, and 50 of the electric exhaust gas heater 2, but other variations (not shown) may also be used, in which the housing 35 is separate from the heater housings 20, 30, and 50. Furthermore, the cross-section of the two first outer rings 40 is not L-shaped, but I-shaped. In addition, the two second inner rings 80 are L-shaped in cross-section, with the L-shape opening outwards toward their respective first rings 40, forming corresponding components together with the first rings. Accordingly, in the electric exhaust gas heater 2, a receiving space for the heating plate 10 is also formed between the two second inner rings 80, where the heating plate 10 is also installed.

[0046] Figure 6 A second inner ring 80 according to the invention is shown. For example, the ring shown here is flattened compared to the associated (not shown) outer ring 40. Ring 80 has a circular outer peripheral edge. Furthermore, it also has an inner peripheral edge with a varying diameter, i.e., having an oval to elliptical portion. The ring 80 shown is point-symmetric with respect to the center of the circular outer peripheral edge. As shown in the accompanying detailed views A and B, ring 80 has a rectangular cross-section and an optional groove at the outer periphery for circumferential positioning. However, if ring 80 has a circular inner peripheral edge and the radius is the same in all locations, such positioning aids are unnecessary. Although such a structure is not shown here, it represents an alternative embodiment of ring 80 according to the invention.

[0047] Figure 7 A cross-sectional view of the third electric exhaust gas heater 3 is shown, its basic configuration being similar to... Figure 1 Same, also based on Figure 2 The AA section view is drawn. In addition, there is a detailed view B derived from the section view.

[0048] Specifically Figure 7 The third electric exhaust gas heater 3 and Figure 3 and Figure 5 The first and second electric exhaust gas heaters 1 and 2 differ in some respects from each other in the shape, number, and arrangement of components in the support structure 70 for the heating plate 10. Figure 3 Similarly, two flattened second inner rings 80 are shown here again. Between the two second inner rings 80 and the two first outer rings 40, Figure 7 An embodiment with an optional L-shaped ring 90, preferably made of metal, is now shown. The advantage of this structure is that it prevents fibers from the first ring 40 from entering the heating area of ​​the heating plate 10. Furthermore, such an L-shaped ring 90 can be produced at low cost using manufacturing processes commonly used in the metalworking industry. Features that are generally applicable or not shown

[0049] about Figure 3 , 5 Regarding the variations of the housing 35 shown in Figure 7, and the number and shape of the inner ring 40 and outer ring 80, it should be noted that other embodiments are also conceivable, wherein any combination of a one-piece or multi-part housing, a one-piece or multi-part first ring 40, and a one-piece or multi-part second ring 80 can be employed. In this case, the cross-section and shape of each ring can also differ; for example, the outer ring perimeter can be annular while the inner ring perimeter can be elliptical, or vice versa. The rings do not necessarily have to be circular, especially when the internal heating element or the outer heater housing is not circular or elliptical.

[0050] The first ring, or both first rings used in this invention, are made of a fibrous material, preferably a ceramic material. This ceramic material is particularly preferably Al2O3, SiO2, or a mullite ceramic material based on a mixture of Al2O3 and SiO2. The first ring, or both first rings, is used for positioning or aligning the heating plate and preferably has at least one flat surface, which, in the assembly with the second ring described below, preferably has suitable adhesive-friction properties, wherein the corresponding coefficient of friction is between 0.1 and 0.8. The material used preferably has good compressibility. Depending on the specific application, the fibrous ring can be compressed to one-half (coefficient 2) to one-fifth (coefficient 5) of its original thickness after installation, preferably to one-third (coefficient 3). For example, before installation, the preferred fibrous ring thickness is about 10 mm to 12 mm, which is compressed, pre-tightened, shrunken, and / or compressed to about 4 mm during installation.

[0051] In addition, at least one or two first outer rings are required to ensure that the heating plate maintains its original position even when subjected to external influences (such as exhaust gas in the exhaust duct of an exhaust aftertreatment system). Such influences particularly include high operating temperatures (typically between 900°C and 1100°C) and high gas pressures, which can sometimes result in accelerations of approximately 60 g to 70 g (1 g = 9.80665 m / s²). 2 Furthermore, due to their special material properties, they act as thermal insulation between the heating plate and the housing. This not only helps protect the housing from the heat of the heating plate but also helps reduce relative movement between the components caused by heat. Despite the presence of axial preload, relative movement between the heating plate and the bearing area is specifically permitted. In this case, it is preferable to employ at least one first or two first outer rings to prevent the heating plate from contacting the housing.

[0052] In applications using a support system for a heating plate, at least one or both first rings come into direct contact with the heating plate over time, causing the base fibers to wear and / or break. This results in corresponding damage to at least one or both first outer rings, ultimately leading to damage to the entire system due to wear and / or erosion. Wear may be caused by thermal abrasion, as the heating plate undergoes multiple heating and cooling processes during use, causing it to expand and contract. Here, it should be particularly assumed that the heating plate expands radially from its center point by a maximum of 1.5 mm, which is applicable to the heating plate of the present invention within the aforementioned parameter range. Potential expansion of the heating plate in the thickness direction is negligible.

[0053] Wear of at least one or both first outer rings may also be caused by the shape of the heating plate, or solely by the shape of the heating plate. For example, sharp edges and / or particularly thin wall elements (such as the individual honeycomb walls of the heating structure) can exacerbate wear on both first rings.

[0054] To prevent premature wear and / or damage to the entire system, the present invention is designed to include at least one or two additional second inner rings made of a different material than the at least one or two first outer rings. Preferably, the thickness of the at least one or two second inner rings is approximately 0.1 mm to 0.8 mm. The material of the at least one or two second inner rings meets the standards for electrical insulators, for example, to prevent electrical short circuits. Furthermore, it optionally has a temperature resistance up to about 1100 °C, preferably about -40 °C to 1100 °C. In high-temperature applications, particularly in the temperature range of 900 °C to 1100 °C, this is especially relevant, for example, when the support structure according to the invention is installed in an electric exhaust gas heater for a gasoline engine.

[0055] Furthermore, it possesses significantly higher wear resistance and mechanical strength. This enhanced wear resistance can be 10 times greater or more compared to applications without at least one or two second inner rings. Internal comparative testing showed that electric exhaust gas heaters without inner rings failed after approximately 3,000 test cycles, while electric exhaust gas heaters with inner rings failed after approximately 50,000 test cycles.

[0056] In addition, it should possess general and / or chemical resistance to exhaust gases, preferably resistance to substances that may appear in the exhaust gas after-treatment system. Furthermore, it may optionally have good plasticity, preferably annular, oval, or elliptical in shape, and / or be erosion resistant.

[0057] For example, the material used for one or both second inner rings can be mica (internationally known as Mica), preferably layered silicates, particularly preferably titanic mica, muscovite, potassium magnesium aluminum silicates containing optional fluoride or hydroxide ions, non-organic binders, or combinations thereof. The material used can be of natural origin or artificially manufactured through appropriate processes. The advantage of artificially manufactured materials is that the desired material properties can be specifically achieved while avoiding contamination from impurities. In this regard, it is particularly worth mentioning that synthetic mica materials have higher temperature resistance than natural mica, meaning they can be used for extended periods at temperatures up to 1000°C.

[0058] Against this backdrop, Table 1 illustrates various specifications, standards to be met, and some corresponding numerical ranges through examples:

[0059] Table 1 Table 1 shows a specific example of a material with at least one or two second inner rings, but other materials are also feasible, especially when it comes to temperature resistance above 1000 °C, particularly under continuous operation conditions.

[0060] By employing specific positioning, for example, a first outer ring or ring portion is arranged between the outer portion of the housing and a second inner ring or ring portion, the second ring or its ring portion interacts with the heating plate and the first ring or both first rings (parts) in the support structure according to the invention, acting as a separation layer or separation element to improve the wear resistance of the entire device. Improved wear resistance of the support structure reduces wear on the entire device, thereby extending its service life and expanding its applicability.

[0061] Alternatively, the two second rings may not be separate components, but rather exist as coatings on corresponding sides of the two first rings. Furthermore, all rings (i.e., one, two, three, or all four rings) may optionally be composed of multiple components. Additionally, all rings or portions thereof may optionally have L-shaped, U-shaped, circular, or rectangular cross-sections, rather than true annular rings. Any combination of rings and cross-sections is included herein, which has a corresponding impact on aspects such as the installability or reconfigurability of the support structure according to the invention, as well as economic aspects (e.g., in terms of the availability of the basic raw materials used). For example, the choice of ring shape may depend on whether the edge regions of the first ring also require protection from the second ring, and / or whether the edge regions of the heating plate contact areas or portions of the first ring and require protection from the second ring to prevent wear / heat. In addition to the embodiments already described and shown, one variation is worth mentioning: the first outer ring is U-shaped and integral. This results in either combination with two inner rings, which may be of different shapes, or only combination with one integral inner ring, also U-shaped.

[0062] During assembly, the first ring and the second ring can be installed as separate components. Alternatively, the first ring and the second ring can be pre-assembled, preferably by means of adhesive or stitching. Alternatively, the second ring can be pre-assembled with the corresponding side of the heating plate, preferably by means of adhesive or stitching.

[0063] In all the described embodiments, the rings, particularly at least one or both first outer rings, are optionally pre-loaded with a predetermined preload or compressive force in the axial direction to withstand external operating conditions. In this case, it must be ensured that the heating plate is subjected to uniform pressure and / or fixation across its entire circumference. The base pressure here preferably reaches a maximum of 15 bar. Depending on the specific application and / or base mounting dimensions, and considering generally applicable tolerances, this pressure is particularly preferably between 2 and 4 bar.

[0064] In addition to the wear mechanisms described above, creep was observed in the fibers of the two first rings towards the center of the heating plate due to expansion and stretching. To further reduce this creep risk, the outer contours of the two first rings can be altered, thereby creating more space between the housing and the support structure. Besides a constant outer diameter, the two first rings can, for example, have alternating grooves and protrusions. The number of protrusions can optionally vary and depends on the size or diameter of the heating plate. Compared to known solutions, this structure can optionally further improve durability, thereby extending product life and preventing customer complaints.

[0065] The invention has been described according to preferred embodiments, wherein the various features of the embodiments can be freely combined and / or interchanged, provided they are compatible. Similarly, certain features of the embodiments may be omitted if not necessary. Many obvious changes and designs can be made by those skilled in the art without departing from the spirit of the invention.

Claims

1. A supporting structure (70) for the heating plate or heating resistor (10) in the exhaust gas system, comprising: A multi-part shell (35); At least one first outer ring (40) made of fibrous material; and At least one second inner ring (80) is made of a non-conductive and heat-resistant material, which is different from the fibrous material of at least one of the first rings (40); Among them, at least one of the second inner rings (80) defines a receiving space for the heating plate or the heating resistor (10).

2. The support structure (70) according to claim 1, wherein, The first ring (40), which is at least one, is two rings, and / or the second ring (80), which is at least one, is two rings; Preferably, a receiving space for the heating plate or the heating resistor (10) is defined between the two second rings (80).

3. The support structure (70) according to claim 1 or 2, wherein, The multi-part housing (35) has at least two metal rings or two metal halves, which are preferably configured to apply a predefined clamping pressure of up to about 15 bar to the first ring and the second ring (40, 80).

4. The support structure (70) according to any one of the preceding claims, wherein, The fiber material is a ceramic material, preferably Al2O3, SiO2, or a mullite ceramic material composed of Al2O3 and SiO2.

5. The support structure (70) according to any one of the preceding claims, wherein, The fiber material has fibers with a diameter of approximately 3µm to 12µm, preferably 5µm to 10µm; and / or The aspect ratio of the fibers in the fiber material is greater than 3:

1.

6. The support structure (70) according to any one of the preceding claims, wherein, At least one of the first rings (40) is compressible, or both of the first rings (40) are compressible, and the compression factor is preferably in the range of 2 to 5 in the installed state.

7. The support structure (70) according to any one of the preceding claims, wherein, The material of at least one or both of the second rings (80) has at least one of the following characteristics: Maximum temperature resistance is 1100 ℃, with a preferred temperature range of -40 ℃ to 1100 ℃; Compressible, flexible and / or bendable; It is malleable, preferably ring-shaped, oval, or elliptical; Resistant to corrosion; Resistant to exhaust gases; and It has chemical resistance, and preferably resistance to substances that may appear in the waste gas after-treatment system.

8. The support structure (70) according to any one of the preceding claims, wherein, The material of at least one of the second rings (80) or both of the second rings (80) is mica, preferably layered silicate, particularly preferably titanic mica, muscovite, potassium magnesium aluminum silicate containing optional fluoride or hydroxide ions, non-organic binder or a combination thereof.

9. The support structure (70) according to any one of the preceding claims, wherein, At least one of the first rings and / or the second ring (40, 80) consists of at least two parts in the circumferential direction; and / or At least one of the first rings and / or the second ring (40, 80) has an L-shaped, U-shaped, circular or rectangular cross-section.

10. The support structure (70) according to any one of the preceding claims, wherein, At least one of the second rings (80) or two of the second rings (80) are present as a coating on the corresponding side of at least one of the first rings (40) or the corresponding first ring (40); and / or The thickness of at least one or both of the second rings (80) is about 0.1 mm to 1.5 mm, preferably about 0.1 mm to 0.8 mm.

11. The support structure (70) according to any one of the preceding claims, wherein, At least one of the second rings (80) or at least one of the two second rings (80) has a metal mesh insert.

12. The support structure (70) according to any one of the preceding claims, wherein, At least one of the first rings (40) or at least two of the first rings (40) have a continuous outer contour; or At least one of the first rings (40) or both of the first rings (40) have alternating grooves and / or protrusions.

13. A support system for an electric heating device, comprising: The support structure (70) according to any one of the preceding claims; and The heating plate or heating resistor (10) is preferably double-sided and has a honeycomb structure and / or multiple slits; in, The heating plate or the heating resistor (10) is located within the receiving space of at least one of the second rings (80) or between two of the second rings (80).

14. The support structure (70) according to any one of claims 1 to 12 or the support system according to claim 13, in, The corresponding first and second rings (40, 80) are pre-assembled, preferably glued or sewn together; and / or The heating plate or the heating resistor (10) is pre-assembled on both sides with the corresponding sides of the second ring (80), preferably by bonding or sewing.

15. The support structure (70) according to any one of claims 1 to 12 or claim 14, or the support system according to any one of claims 13 or 14, further comprising: Multiple pins (60) for positioning, supporting, fixing the heating plate or the heating resistor (10) and / or for electrical insulation between local areas of the heating plate or the heating resistor (10). in, The plurality of said pins (10) are preferably spacer elements; Particularly preferred is that some of the spacer elements are designed as fixing devices located in corresponding recesses in the housing (35), wherein at least one end of the fixing device is directly mechanically connected to the housing (35); and / or At least a portion of the spacer element is located between the two second rings (80), preferably pre-tightened.

16. The support system according to any one of claims 12 to 15, wherein, At least one of the second rings (80) or both of the second rings (80) only contact the edge region of the heating plate or the heating resistor (80) in the circumferential direction, wherein the edge region is not actively heated.

17. An electric exhaust gas heater, having the following features: The support system according to any one of claims 12 to 16; The heater housing (20, 30, 50), preferably made of metal, is located in the exhaust gas duct of the exhaust gas aftertreatment system and is provided to accommodate the support system (70).

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