EXHAUST ENGINEERING UNIT AND VEHICLE

Description

[0001] The invention relates to an exhaust gas treatment device for a motor vehicle, comprising a housing that defines an exhaust gas channel through which the exhaust gas flows, a separate electric heating device extending through the exhaust gas channel and through which exhaust gas flows, configured to heat the exhaust gas separately from an exhaust gas purification device, and which does not perform a purification function, and comprising a heating component and a support structure, wherein the heating component is attached to the support structure, and a first and a second electrode attached to the heating device and electrically contacting the heating device. The invention further relates to a vehicle with an exhaust gas treatment device.

[0002] To limit pollutant emissions from motor vehicle combustion engines, it is known to use exhaust gas purification devices, such as catalysts, particulate filters or the like.

[0003] To ensure catalytically assisted conversion of pollutants, the exhaust gas or the exhaust gas purification system must reach a specified minimum temperature. This minimum temperature is often not reached, particularly after a cold start or restart of the combustion engine.

[0004] According to one embodiment, the exhaust gas purification devices themselves are electrically heated in exhaust gas treatment systems to reach or maintain the specified minimum temperature. These exhaust gas treatment systems are not related to the present invention.

[0005] Alternatively, and this relates to the present invention, separate heating devices are used which are associated with the exhaust gas purification device but are positioned upstream of it in terms of flow. In these separate heating devices, electrodes provide the power supply and additionally provided fastening means provide the mounting.

[0006] US 5,744,104 A shows a main converter to which a heating converter in the form of an electrically contacted, self-heating monolith is connected.

[0007] German patent application DE 10 2013 217 009 A1 discloses a heated catalyst with a monolith divided into multiple segments and heated by an electric heating element. The monolith is wound, forming two separate resistance paths, and is held by a metal-based inner casing.

[0008] US Patent 5,672,324 A shows an exhaust pipe with an electric heater located upstream of a separator filter. The heater consists of a central electrode, a ring electrode, and a multi-layered heat source in the form of flat and corrugated foil sheets bonded together.

[0009] DE 10 2018 107 825 A1 describes a heater in which three sheets insulated against each other with insulating sheets are wound together, with each of the sheets being contacted with an electrode in the middle and an electrode in a radially outer edge region.

[0010] German patent application DE 10 2005 011 657 A1 discloses an evaporator tube designed as a heat conductor, which is arranged in an exhaust gas line upstream of a catalyst. Fluid can flow inside the evaporator tube. The evaporator tube can be electrically heated to evaporate the fluid flowing within it.

[0011] The object of the invention is to provide a simple, reliable and separate heating device for an exhaust gas treatment system.

[0012] The object of the invention is achieved by the first electrode extending into a central region of the heating device and the second electrode extending into an edge region of the heating device, as seen in the exhaust gas flow direction in the exhaust gas duct, wherein either the support structure has at least one support frame surrounding the heating device on the outside, which is attached to the housing insulated from the housing by at least one fastening element and / or is attached to the housing insulated from the housing by at least one second electrode, or the heating component is attached directly to the first electrode and the second electrode(s) and / or to fastening elements, wherein the electrodes and the fastening elements are insulated from the housing.

[0013] Since the first electrode extends into the central area of ​​the heating device and the heating component is attached to the first electrode, deformation of the heating device can be reduced or avoided. Furthermore, the central current input or output allows for a more uniform heating of the device across the flow cross-section.

[0014] Because the heating device is a separate, independent component from the exhaust gas cleaning system, serving only to heat the exhaust gas and not performing any cleaning function, and is therefore located upstream of the cleaning unit, the exhaust gas treatment system can be designed modularly. This simplifies assembly and disassembly. Furthermore, more efficient heating of the exhaust gas is ensured, as no material from the associated exhaust gas cleaning system is heated concurrently. Additionally, the heating device can be positioned anywhere upstream of the exhaust gas cleaning system, as it is not integrated into it.

[0015] In particular, the two electrodes serve as mechanical fasteners by which the heating device is attached to the housing. The two electrodes provide the power supply and also secure the heating device. In other words, the electrodes are part of the support structure. The housing serves as a common enclosure for both the exhaust gas purification system and the heating device.

[0016] Optionally, the heating device and the exhaust gas cleaning device can each have a separate housing.

[0017] In particular, the heating device is arranged upstream of the exhaust gas cleaning device in the direction of exhaust gas flow.

[0018] The support frame serves to stabilize the heating component across its entire circumference.

[0019] The support frame may have a recess in the area of ​​a connection point between the second electrode and the heating component, particularly in the edge area.

[0020] Optionally, the support frame can be completely enclosed.

[0021] In particular, the support frame can be made of an electrically conductive or an electrically insulating material and form part of the second electrode.

[0022] An electrically conductive support frame has the advantage that the heating component can be contacted over a larger area. This increases the reliability of the contact and improves the current flow in the heating component.

[0023] The stability of the support frame, and therefore of the heating device, can be increased by using at least one fastening element. Using multiple secondary electrodes for fastening can further improve the reliability of the contact and the current flow in the heating component.

[0024] Preferably, the edge region is a circumferentially closed frame area whose radial extent is defined by the radial extension of the second electrode and / or the support structure, and / or the edge region circumferentially encloses the central region. Depending on how far the second electrode extends radially into the heating device towards the central region, the radial width of the edge region is larger or smaller. This directly influences the extent of the central region.

[0025] In particular, the current flows between the two electrodes in a radial direction, especially from the central region to the edge region or vice versa. Therefore, there is (essentially) no current flow in an axial direction, viewed in or against the exhaust gas flow direction.

[0026] One embodiment provides that the two electrodes are coupled only to the heating component on the heating device side and to the housing and / or a mounting sleeve attached to an outer surface of the housing on the housing side. The electrodes must necessarily be coupled to the heating component to establish electrical contact. Since they are coupled only to the heating component on the heating device side and do not come into contact with any other component in this area that is not intended to be electrically connected, the need for a complex insulated connection point is eliminated. The housing-side mounting makes the electrodes easily accessible. Furthermore, this housing-side mounting is easy to implement.

[0027] Another aspect stipulates that the first electrode and / or the second electrode and / or the mounting element extend through the housing towards the heating device and are each received in a mounting sleeve attached to the housing. The mounting sleeve serves to protect the through-hole as well as the electrodes and / or the mounting element from dirt, moisture, or the like. Furthermore, the mounting sleeve ensures the airtightness of the exhaust gas treatment device.

[0028] Preferably, the first electrode and / or the second electrode and / or the fastening element are insulated in the area of ​​the housing and / or the fastening sleeve, in particular by glass and / or ceramic insulation.

[0029] In another embodiment, the support frame is electrically conductive and thus forms part of the first electrode and / or the second electrode. This significantly increases the area in which the heating component is supplied with current, thereby increasing the reliability of the contact and improving the current flow in the heating component.

[0030] According to another aspect, the heating component is a rigid heating grid that is contacted by the first electrode in the central area and coupled to the second electrode at the edges. Such a heating grid is easy to manufacture, as it can be electrolytically machined or stamped from a sheet of metal, for example. Depending on the size of the openings, the exhaust gas flow resistance caused by the heating device, as well as the heating intensity, can be influenced. Such a heating grid can also be easily installed in the heating device or the exhaust gas treatment system.

[0031] In particular, the heating grid is preferably mounted on the outside of the support frame, especially at the edges. This increases the stability of the heating grid.

[0032] The support frame can comprise electrically conductive material and be contacted by the electrodes. In this way, the support frame can form part of the electrodes, increasing the contact area available to the heating component. This can improve the reliability of the contact and the current flow in the heating component.

[0033] Another aspect involves a gap between the heating element and the housing, which is optionally filled with insulating material. This gap serves to reduce or prevent interactions between the heating element and the housing and to compensate for manufacturing inaccuracies. Using insulating material reliably prevents such interactions.

[0034] Furthermore, the task is solved by a vehicle with an internal combustion engine and an exhaust gas treatment system.

[0035] The described advantages and properties of the exhaust gas treatment device according to the invention apply equally to the vehicle and vice versa.

[0036] Further advantages and features of the invention will become apparent from the following description and the drawings, to which reference is made. The drawings show: Figure 1 a schematic longitudinal section of an exhaust gas treatment device according to the invention, Figure 2 a further schematic longitudinal section of the exhaust gas treatment device according to the invention, Figure 3 a top view of a first embodiment of a heating device according to the invention of the exhaust gas treatment device according to the invention Figure 1 or Figure 2 , Figure 4 a top view of a second embodiment of the heating device of the exhaust gas treatment device according to the invention Figure 1 or Figure 2 , Figure 5 a sectional view of the heating device according to the invention Figure 3 or Figure 4, with a first embodiment of a connection of a heating component to a housing, Figure 6 a sectional view of the heating device according to the invention Figure 3 or Figure 4 , with a second embodiment of connecting the heating component to the housing, Figure 7 a sectional view of the heating device according to the invention Figure 3 or Figure 4 , with a third embodiment of connecting the heating component to the housing,

[0037] In Figures 1 and 2 Two exemplary embodiments of an exhaust gas treatment device 10 are shown schematically in a longitudinal section. The exhaust gas treatment device 10 is provided in an exhaust gas duct 13 and comprises a heating device 12, an exhaust gas cleaning device 15, and a housing 14.

[0038] In both embodiments, the heating device 12 is arranged upstream of the exhaust gas purification device 15, spaced apart in the exhaust gas flow direction 11.

[0039] The heating device 12 is therefore a separate component independent of the exhaust gas purification device 15, which serves only to heat the exhaust gas and has no cleaning function and is not integrated into it.

[0040] In Figure 1 The housing 14 is a common housing 14 that is assigned to the heating device 12 and the exhaust gas cleaning device 15.

[0041] In Figure 2 The housing 14 is designed as a separate housing 14, each assigned to the heating device 12 and the exhaust gas purification device 15.

[0042] In Figure 3 The exhaust gas treatment device 10 is shown in cross-section with a view in the direction of exhaust gas flow 11. The exhaust gas treatment device 10 comprises the heating device 12 and the housing 14.

[0043] The heating device 12 consists of a heating component 20 and a support structure, wherein the support structure has a first electrode 16, a second electrode 18, two fastening elements 22 and a support frame 24 surrounding the heating component 20 on the outside.

[0044] Optionally, the heating device 12 can also have several or fewer second electrodes 18 and / or fastening elements 22.

[0045] The heating component 20 is made of an electrically conductive material and in this embodiment is designed as a self-rigid heating grid.

[0046] The heating grid can, for example, be made of a sheet of metal.

[0047] The heating device 12 is arranged in the exhaust duct 13 via the support structure and is attached to the housing 14 in such a way that a gap 26 is present between the housing 14 and the heating device 12.

[0048] The gap 26 reduces or prevents interactions between the heating device 12 and the housing 14. In addition, manufacturing inaccuracies can be compensated for by the gap 26.

[0049] The gap 26 can also be filled with a filling material, such as insulation.

[0050] The first electrode 16 extends through the housing 14 into a central area 28 of the heating device 12 and is electrically and mechanically connected to the heating component 20 in this area.

[0051] The first electrode 16 can be attached, for example, by external welding to the housing 14.

[0052] The support frame 24 is provided at an edge area 29 of the heating component 20.

[0053] The radial extent of the edge region 29 in the direction of the central region 28 is determined by the radial extent of the second electrode 18 and / or the support structure.

[0054] The second electrode 18 and the fastening elements 22 are indirectly or directly connected to the support frame 24 and thereby secure the heating device 12 in the housing 14.

[0055] The support frame 24 and its connection with the second electrode 18 and the fastening elements 22 will be described further below ( Figures 5-7 ) discussed in more detail.

[0056] The heating component 20 is electrically and mechanically connected to the second electrode 18.

[0057] The second electrode 18 and the fastening elements 22 extend through the housing 14 and are received in a fastening sleeve 30 attached to the outside of the housing 14.

[0058] The fastening of the fastening sleeves 30 can be done, for example, by external welding to the housing 14.

[0059] The housing 14 and the mounting sleeves 30 are electrically or galvanically decoupled from the second electrode 18 and the mounting elements 22 by means of insulation 32. This prevents electrical interactions between the second electrode 18 or the mounting elements 22 and the housing 14 or the mounting sleeve 30.

[0060] The insulation 32 of the second electrode 18 and the second electrode 18 extend through the housing 14 and the mounting sleeve 30. Cables or wires, for example, which are needed to create an electrical circuit, can be connected to the outer end of the second electrode 18.

[0061] When current flows, current flows via the first electrode 16 into the central area 28 of the heating component 20 and further (essentially) in a radial direction and, according to the course of the heating component, also partly in a circumferential direction to the edge area 29 to the second electrode 18.

[0062] Alternatively, the current can also flow in reverse.

[0063] The heating component 20 heats up when current flows, which also heats the exhaust gas flowing through the heating device 12.

[0064] The heated exhaust gas then flows into the exhaust gas cleaning device 15 and heats it up in the process. This significantly increases the efficiency of the exhaust gas cleaning.

[0065] Figure 4 shows a second embodiment of the heating device 12, which is based on the first embodiment described above. Figure 3 similar. Accordingly, similar or identical components are provided with the same reference numerals, and reference is made to the explanations above.

[0066] Instead of the fastening elements 22 in the first embodiment of the heating device 12, the second embodiment provides two further second electrodes 18'. The design and function of the additional second electrodes 18' and their attachment to the housing 14 are almost identical to those of the second electrode 18.

[0067] The second electrodes 18, 18' are connected to each other via a connecting cable 34.

[0068] In this embodiment, the second electrode 18 is extended and projects further towards the central region 28 of the heating device 12. Accordingly, the radial extent of the edge region 29 is larger and consequently of the central region 28 smaller than in the first embodiment according to Figure 3 .

[0069] Due to the extended second electrode 18 and the two further second electrodes 18', the deformation stress of the heating device 12 can be reduced and the contact area can be increased, which increases the reliability of the contact and improves the current flow in the heating component.

[0070] In the Figures 5, 6 and 7 The exhaust gas treatment device 10 is shown in a longitudinal section. The focus here is on the various connection types of the second electrode 18 or the fastening elements 22 with the support frame 24 or the heating component 20.

[0071] In Figure 5 The heating component 20 is attached directly to the first electrode 16 and the second electrode(s) 18, 18' and / or the mounting elements 22. This is possible because the second electrodes 18, 18' and the mounting elements 22 are each insulated from the housing 14 and the mounting sleeve 30.

[0072] Figure 6 Figure 1 shows another embodiment in which the support frame 24 is arranged between the second electrode(s) 18, 18' and / or the fastening elements 22 and the heating component 20.

[0073] Such a connection is only possible at the second electrodes 18, 18' if the support frame 24 comprises electrically conductive material.

[0074] In this embodiment, too, the support frame 24 can be completely enclosed.

[0075] It would of course be conceivable to provide such a connection only at the fastening elements 22 and at the electrodes 18, 18' a connection according to the embodiment shown Figure 5 to apply.

[0076] The support frame 24 cannot be completely closed, but would have to have a recess in the area of ​​the second electrodes 18, 18'.

[0077] In Figure 7 is a to Figure 6 A similar embodiment is shown.

[0078] The use of such a connection at the second electrodes 18, 18' can be ensured on the one hand by an electrically conductive support frame 24 and on the other hand by the second electrodes 18, 18' extending through the support frame 24, in particular through the part of the support frame 24 perpendicular to the second electrodes 18, 18', and being directly connected to the heating component 20.

[0079] In this embodiment, the support frame 24 can be completely closed.

[0080] Here too, it would of course be conceivable to provide such a connection only at the fastening elements 22 and at the electrodes 18, 18' a connection according to the embodiment shown. Figure 5 to apply.

[0081] Of course, other types of connections and combinations of the connection types mentioned above are also possible.

Claims

1. An exhaust gas treatment device for a motor vehicle, comprising a housing (14) which defines an exhaust gas duct (13) through which the exhaust gas flows, a separate electric heating device (12) which extends through the exhaust gas duct (13) and through which exhaust gas flows and which is configured to only heat the exhaust gas at a distance from a separate exhaust gas purification device (15), and which does not perform a purification function and which comprises a heating component (20) and a carrier structure, the heating component (20) being attached to the carrier structure, and first and second electrodes (16, 18), which are attached to the heating device (12) and make electrical contact with the heating device (12), wherein the first electrode (16) extends as far as into a central region (28) of the heating device (12), and the second electrode (18) extends as far as into an edge region (29) of the heating device (12), as viewed in the exhaust gas flow direction (11) in the exhaust gas duct (13), characterized in that either the carrier structure has at least one support frame (24) which surrounds the heating device (12) on the outside and which is attached to the housing (14) by means of at least one fastener (22) so as to be insulated from the housing (14) and / or is attached to the housing (14) by means of at least one second electrode (18') so as to be insulated, or the heating component (20) is directly attached to the first electrode (16) and the second electrode(s) (18, 18') and / or to fasteners (22), the electrodes (16, 18, 18') and the fasteners being insulated from the housing (14).

2. The exhaust gas treatment device according to claim 1, characterized in that the edge region (29) is a circumferentially closed frame region the radial extension of which is defined by the radial extent of at least one of the second electrode (18) and the carrier structure, and / or in that the edge region (29) circumferentially encloses the central region (28).

3. The exhaust gas treatment device according to either of the preceding claims, characterized in that the current flow between the two electrodes (16, 18) takes place in the radial direction, from the central region (28) to the edge region (29), or vice versa.

4. The exhaust gas treatment device according to any of the preceding claims, characterized in that, on the heating device side, the two electrodes (16, 18) are coupled only to the heating component (12) and, on the housing side, they are coupled to at least one of the housing (14) and a fastening sleeve (30) attached to an outside of the housing (14).

5. The exhaust gas treatment device according to any of the preceding claims, characterized in that at least one of the first electrode (16), the second electrode (18) and the fastener (22) extends through the housing (14) toward the heating device (12) and each is received in a fastening sleeve (30) attached to the housing (14).

6. The exhaust gas treatment device according to any of the preceding claims, characterized in that the support frame (24) is electrically conductive, thereby forming part of the first electrode (16) and / or the second electrode (18).

7. The exhaust gas treatment device according to any of the preceding claims, characterized in that the heating component (20) is an inherently stiff heating grid, which is contacted by the first electrode (16) in the central region (28) and is coupled to the second electrode (18) in the edge region (29).

8. The exhaust gas treatment device according to any of the preceding claims, characterized in that the heating grid, in particular in the edge region (29), is mounted on its outside to the support frame (24).

9. The exhaust gas treatment device according to any of the preceding claims, characterized in that between the heating device (12) and the housing (14) there is a gap (26) which in particular is filled by an insulating material.

10. The exhaust gas treatment device according to any of the preceding claims, characterized in that an exhaust gas purification device (15) is provided downstream of the heating device (12) and spaced apart therefrom in the flow direction.

11. A vehicle comprising an internal combustion engine and an exhaust gas treatment device according to any of the preceding claims.