An assembly for an exhaust aftertreatment device, a heating system, the exhaust aftertreatment device, a method for using the assembly, and a method for replacing a heating element in the exhaust aftertreatment device.

Abstract

An assembly for an exhaust aftertreatment device comprising: an electric heating element with an exhaust gas flow direction; a housing element configured to accommodate the electric heating element interchangeably; wherein the housing element has a passage part in which the heating element is arranged; wherein the housing element has a hood part, the hood part having a wall in the exhaust gas flow direction, and wherein a cavity is formed between the wall and the heating element.

Description

Field of invention

[0001] The present invention relates generally to an assembly for an exhaust aftertreatment device and in particular to a replaceable heating element in the assembly. Background of the invention (and prior art)

[0002] The efficiency of exhaust aftertreatment systems depends heavily on the exhaust gas temperature itself, as well as on the temperature of any exhaust gas purification components present, such as a catalytic converter. Reaching a minimum operating temperature for the entire exhaust aftertreatment system therefore has a significant impact on its resulting exhaust gas purification performance. Consequently, the general goal is to reach this minimum operating temperature as quickly as possible in order to minimize the overall pollutant emissions of a vehicle. A suitable method for further reducing the necessary warm-up time is the use or installation of a heating element to heat the exhaust gas at the point of impact. Heated exhaust gas can be more easily treated, for example, to reduce the proportion of nitrogen oxides (NOx). xto minimize the costs associated with inspecting and / or replacing the heating element in conventional exhaust aftertreatment systems. Inspecting and / or replacing the heating element is difficult, time-consuming, and expensive. Often, the heating element is located in a hard-to-reach place. Numerous steps are required, and the available working space for the mechanic is limited. Furthermore, parts of the exhaust aftertreatment system may need to be damaged to access and / or replace the heating element. Therefore, a simple, cost-effective, and quick way to inspect and / or replace the heating element is desirable.

[0003] Document EP 1 484 481 A1 discloses an exhaust gas purification device comprising a tubular housing arranged in the exhaust ducts of an internal combustion engine. A heating element within a heating housing is also disclosed. The ends of the heating element extend through parts of the heating housing, thus making the heating element not individually replaceable.

[0004] Document EP 4 283 099 A1 discloses an exhaust aftertreatment system with an electric heating element and a cover. There is no cavity between these elements, making replacement of the heating element difficult. Furthermore, exhaust gas only partially flows through the heating element, as it is deflected laterally. Similarly, document US 2022 / 0 307 400 A1 discloses an exhaust aftertreatment unit for cleaning exhaust gases. Here, too, no cavity is disclosed between the heating element and the cover.

[0005] Furthermore, US 11,933,210 B2 teaches an exhaust aftertreatment unit for cleaning exhaust gases, comprising: an emission reduction module, which is a diesel particulate filter and / or a diesel oxidation catalyst; a selective catalyst; an electric heating element located upstream of the emission reduction module; a housing that accommodates the emission reduction module and the electric heating element; and a maintenance cover that is removable and covers a maintenance opening in the housing through which the emission reduction module can be accessed. The heating element is removable relative to the housing and is accessible after removing the maintenance cover and the emission reduction module. Object of the invention

[0006] The object of the present invention is to overcome one or more of the problems or disadvantages associated with the prior art. Summary of the invention

[0007] The above-mentioned problem and further problems are solved by an assembly for an exhaust aftertreatment device according to main claim 1. The dependent claims and the collateral claims relate to preferred embodiments of the invention.

[0008] The present invention relates to an assembly for an exhaust aftertreatment device comprising: an electric heating element with an exhaust gas flow direction; a housing element configured to receive the electric heating element interchangeably; the housing element having a passage in which the heating element is arranged; the housing element having a hood, the hood having a wall in or against the exhaust gas flow direction, and a cavity being formed between the wall and the heating element. The electric heating element can be subjected to flow in both directions, so that its function can be direction-independent.

[0009] The electric heating element (or simply heating element) can be a permeable heating element. This allows exhaust gas to flow through the heating element (this is also facilitated by the cavity), which in turn enables the transfer of heat energy from the heating element to the flowing medium (e.g., air or exhaust gas). This results in more efficient heating of the exhaust gas. The heating element can be a heating coil, in which the temperature increase preferably occurs due to electrical resistance. The heating element has a defined exhaust gas flow direction. This means that the exhaust gas can flow through the heating element in at least this direction. In some embodiments, the exhaust gas can also flow through the heating element in a different direction (e.g., the opposite direction) if the rest of the system and the gas pressure permit it.For example, the exhaust gas flow direction in the embodiments shown in the figures can be identified by arrows (for example, for an exhaust gas flow 28).

[0010] The housing element comprises the through-hole section and the cover section. The housing element can accommodate the heating element using the through-hole section.

[0011] The heating element is located within the through-passage section. The heating element can be interchangeably positioned within the through-passage section, for example, by means of a screw, clamp, flange, threaded, or welded connection.

[0012] The hood section is designed to redirect the incoming exhaust gas, i.e., to change the direction of gas flow (outside the heating element), from approximately 45° up to 180° or even beyond. Because the hood section has a wall oriented in the direction of exhaust gas flow within the heating element (exhaust gas passage direction), it is not a straight pipe. The exhaust gas flows both through the heating element and through an opening. From the perspective of the cavity, the exhaust gas can flow in through the heating element and out through the opening, or out through the heating element and in through the opening. The wall is spaced away from the heating element, thus forming the cavity.

[0013] This design places the cover on the outside of the system, making it easier to access for assembly and disassembly. This easy access allows for inspection and / or replacement of the heating element. This process is quick, cost-effective, and simple.

[0014] In some embodiments, the parts of the assembly according to the invention are circularly symmetrical and / or have a common central axis. In some embodiments, the parts of the assembly are circularly symmetrical with the exception of the hood part.

[0015] Furthermore, the mounting can be non-destructively replaceable. This means that the heating element can be replaced without damaging the housing. "Non-destructive" can mean that no damage occurs to the housing, preferably to all affected parts. Examples of non-destructive connections include at least one of the following: screw, clamp, flange, and threaded connections. Alternatively, the electric heating element can be mounted in the housing in such a way that the housing is cut and / or broken at a predetermined point and can be reassembled after replacement. This predetermined point can be a separation point and / or a point where nothing else is damaged. Reassembly can be achieved by welding.

[0016] Furthermore, the housing element can be configured to redirect exhaust gas flowing in through the heating element into the cavity. In addition, the housing element can be configured to redirect exhaust gas flowing out through the heating element into the cavity before it flows out through the heating element.

[0017] Furthermore, the cross-section of the heating element can be smaller than the cross-section of the through-flow section. This can create an annular gap between the heating element and the inner diameter / cross-section of the hood section, which can, for example, allow a reversal of the flow direction.

[0018] For example, the cross-sectional area of ​​the heating element can correspond to at least 50% of the cross-sectional area of ​​the through-pass part, preferably 30 to 70%, particularly preferably 50 to 60%.

[0019] Furthermore, the heating element can be positioned in the passage section in such a way that an area of ​​the passage section not covered by the heating element remains free. This can also create an annular gap between the heating element and the inner diameter / cross-section of the hood section, which can, for example, allow a reversal of the flow direction.

[0020] The uncovered area of ​​the passage section can be the opening described earlier, through which the exhaust gas also flows. In this case, the exhaust gas also flows around the heating element, in the opposite direction to the direction in which it flows through the heating element. To separate the flow directions, a dividing element can be arranged directly around the heating element. The dividing element can be a wall, part of an exhaust housing or exhaust pipe, and / or similar.

[0021] Alternatively, the heating element can completely fill the passage, meaning it can have the same cross-section as the inner cross-section of the passage. In this case, the opening can be positioned elsewhere, for example, in the hood section. The opening can be located at any aerodynamically favorable point on the hood section. Preferably, the opening is located at a central point on the hood section, which is also referred to as an axial inlet or axial inlet position.

[0022] Furthermore, the heating element can be a heating disc. Depending on the design, this can advantageously provide a particularly good heat exchange surface due to its relatively short length and simultaneously relatively large diameter.

[0023] Furthermore, the heating element and the through-pass part can each have a round cross-section.

[0024] The heating element can be disc-shaped, i.e., cylindrical with a height less than its diameter. In this case, the height is not zero. The height can be parallel to the exhaust gas flow direction. The passage section can be ring-shaped. The disc-shaped heating element and the ring-shaped passage section can have parallel axes of circular symmetry. The axes of circular symmetry can be identical. Examples of this are described directly below. These optional features can also advantageously contribute to ensuring the largest possible heat exchange surface, even in limited installation space.

[0025] Furthermore, the heating element can be positioned centrally in the passage section, and a free area of ​​the passage section can be ring-shaped.

[0026] The unobstructed area of ​​the passage is the opening through which the exhaust gas flows. This opening can be ring-shaped. This makes the exhaust gas flow more uniform and thus improves it.

[0027] Furthermore, the hood component can serve as a cover. The cover can be easily removed and reattached. The cover (thus the hood component) can be connected to the rest of the assembly using screws, clamps, flanges, or threaded connections. Removing the cover allows easier access to the heating element during servicing or repairs.

[0028] Furthermore, the housing element can have an additional through-passage section, separate from the first through-passage section. This additional through-passage section can be positioned towards the cover section relative to the first through-passage section. The additional through-passage section can secure the cover (and thus the cover section) by means of a screw, clamp, flange, or threaded connection.

[0029] Furthermore, the housing element can have a fastening component designed for attaching the assembly to an exhaust housing of the exhaust aftertreatment device by means of at least one of the following: screw, clamp, flange, or threaded connection. The exhaust housing can, as required, accommodate several components (side by side and / or one behind the other in the direction of flow). The exhaust housing can also be in the form of an exhaust pipe.

[0030] The present invention further relates to a heating system for an exhaust aftertreatment device, comprising: the assembly according to the invention as described above; and a fastening device configured for fastening the assembly to an exhaust housing of the exhaust aftertreatment device by means of at least one of the following: screw, clamp, flange and threaded connection.

[0031] The fastening device can be the same as the fastening part.

[0032] Alternatively, the assembly can be welded to an exhaust housing. The heating system can have a designated separation point for servicing and / or a marking for any necessary separation cut. At this separation point / marking, the heating system can be selectively separated, for example, by cutting, and then reassembled, for example, by welding, after maintenance and / or replacement of the heating element. This prevents damage to other parts. Optionally, the separation point has properties that differ from the surrounding material to facilitate separation (for example, a reduced material thickness). However, these different material properties do not negatively affect the durability and / or function of the overall system. Alternatively, the through-flow section can be part of the exhaust housing. The exhaust housing containing the through-flow section can be formed in one piece.This can result in fewer individual parts being required overall, and potentially necessary subsequent joining (such as welding, etc.) can also be eliminated. Furthermore, it becomes possible to manufacture an assembly with a lower overall weight if, for example, a flange connection can be omitted.

[0033] The assembly can be attached in the direction of exhaust flow at the end of the exhaust housing, at the beginning of the exhaust housing, or between two parts of the exhaust housing.

[0034] The present invention further relates to an exhaust aftertreatment device comprising: a heating system as previously described; and an exhaust housing with at least one exhaust aftertreatment element.

[0035] Furthermore, at least one exhaust aftertreatment element can be a (diesel) particulate filter, a catalytic converter and / or an injector.

[0036] At least one exhaust aftertreatment element can be positioned downstream of the heating element. The assembly can be positioned at an inflow downstream of the exhaust aftertreatment element. Alternatively, the assembly can also be positioned downstream of the exhaust aftertreatment element. Since exhaust aftertreatment systems can consist of several individual exhaust aftertreatment elements, a single element, out of a total of several, can also be functionally and / or from a flow perspective located upstream of a subsequent exhaust aftertreatment element and heat it up.

[0037] Furthermore, the hood part can be attached to the exhaust housing in such a way that a cross-section of the exhaust housing overlaps with a cross-section of the heating element and that preferably the heating element closes off the exhaust housing.

[0038] The assembly can be attached directly to the end (outlet) of the exhaust housing. Another exhaust housing, or even a further section of the exhaust housing, can be attached downstream of the assembly and possibly even downstream of the exhaust aftertreatment element. The exhaust housing can direct exhaust gas directly to the heating element or the opening, and the other exhaust housing can direct exhaust gas directly from the heating element and opening of the other housing. Alternatively, the exhaust housing can direct exhaust gas directly from the heating element or the opening, and the other exhaust housing can direct exhaust gas directly to the heating element and opening of the other housing.

[0039] The assembly can be integrated into systems with a combustion engine. Depending on the application, the combustion engine can be an engine, such as an internal combustion engine (ICE), a hydrogen fuel cell or a hydrogen-based engine, a generator, a coal-fired power plant, a combination of these, or similar. The system could be, for example, a passenger car or a truck.

[0040] The present invention further relates to a method for using the assembly according to the invention as described above, which comprises: heating exhaust gas which flows through the heating element, preferably in the exhaust gas flow direction; and redirecting a gas flow direction of the exhaust gas in the cavity.

[0041] The redirection within the cavity is caused by the wall. This redirection is a change in the exhaust gas flow direction within the cavity relative to an upstream exhaust gas flow direction. Therefore, the exhaust gas flows in a different direction behind the assembly than it did in front of it.

[0042] Furthermore, the method can be a method for using the assembly according to the invention as described above. It can also include the following: diverting the heated, redirected exhaust gas from the cavity via a free area of ​​the passage section, preferably after redirection by 180°; or directing the as yet unredirected and unheated exhaust gas into the cavity via a further passage section.

[0043] The exhaust gas flow direction can be redirected by an angle of 45° or 70° up to 270°, preferably 90° to 270° or 100° to 270°, and particularly preferably by at least 180°. In particular, an angle of 180° represents a complete reversal of the exhaust gas flow direction. The redirection angle can be achieved by the geometry of the assembly, preferably the hood section.

[0044] The present invention further relates to a method for replacing the heating element in the exhaust aftertreatment device, comprising: removing the assembly from the exhaust housing; replacing the heating element, preferably non-destructively, in the assembly; and reassembling the assembly on the exhaust housing. Brief description of the drawings

[0045] The invention, as well as further details and advantages thereof, are explained below with reference to preferred embodiments and the figures, where identical designations denote identical elements. The figures show: Fig. 1 a schematic view of an exhaust aftertreatment device; Fig. 2 a cross-section of an assembly in an exhaust aftertreatment device; Fig. 3a a view of an assembly in an exhaust aftertreatment device; Fig. 3b a cross-section of an assembly in an exhaust aftertreatment device; Fig. 4 a method for using an assembly; Fig. 5 a method for replacing a heating element in the exhaust aftertreatment device. Fig. 6a to 6c different configurations of exhaust aftertreatment devices with different arrangements of the exhaust aftertreatment elements and heating element positions. Detailed description of the invention

[0046] In this description, the terms top, bottom, right, and left, as well as similar terms, refer to the orientations or arrangements shown in the figures and serve only to describe the exemplary embodiments. These terms may indicate preferred arrangements but are not to be understood in a restrictive sense.

[0047] Furthermore, the terms “essentially”, “approximately”, “about”, and similar expressions mean that deviations of + / -10%, preferably + / -5%, from the stated value are permissible.

[0048] Unless explicitly excluded, the value ranges mentioned herein are always understood to include lower bounds marked with "≥" (greater than or equal to) and upper bounds marked with "≤" (less than or equal to) within the specified value range. Thus, the bounds themselves are either included in the respective range or may alternatively be (unilaterally) excluded.

[0049] Fig. Figure 1 shows a schematic view of an exhaust aftertreatment device 10. The exhaust aftertreatment device 10 comprises a heating system 12 and an exhaust housing 14 (only one end shown) with an exhaust aftertreatment element 16 (which may be and / or include a substrate, catalyst, and / or exhaust filter). The heating system 12 comprises an assembly 18 and a mounting device 20. The assembly 18 is shown outlined by dashed lines. The assembly 18 comprises an electric heating element 22 and a housing element 24. The housing element 24 comprises a passage section 26 and a hood section 28. The hood section 28 comprises a wall 30 (since the wall 30 is enclosed by the hood section 28, these reference numerals point to the same) and side walls 32. A cavity 34 is located between the heating element 22 and the wall. An optional exhaust mixing element 36 is also shown. Arrows schematically show the course of an exhaust gas flow 38 (thick arrows).Furthermore, an opening 40 is shown.

[0050] The exhaust gas aftertreatment device 10 is configured such that an exhaust gas stream 38 first flows through an exhaust gas aftertreatment element 16, then through the heating element 22 into the cavity 34. Thus, the exhaust gas flow direction of the heating element 22 is from right to left, as indicated by the arrow. In the cavity 34, the exhaust gas stream 38 is redirected at the wall 30, changing its direction. The exhaust gas stream 38 then exits the cavity 34 through the opening 40. Afterward, the exhaust gas stream 38 enters the exhaust gas mixing element 36. An exhaust gas flow opposite to the arrows is possible.

[0051] The opening 40 is positioned next to the heating element 22. Here, the opening 40 is asymmetrical. This redirects and reverses the exhaust gas flow 38 upwards. Alternatively, the opening 40 can be located in a side wall 32.

[0052] The fastening device 20 secures the assembly 18 to the exhaust housing 14. The fastening device 20 can comprise at least one of the following: screw, clamp, flange, and threaded connection. Fig. Figure 1 shows the fastening device 20 at an exemplary location above. However, the fastening device 20 can also fasten the assembly 18 to the exhaust housing 14 at several locations (not shown). For example, the fastening device 20 can extend around the exhaust housing 14. The fastening device 20 can contact the exhaust housing 14 and / or fasten it indirectly (via at least one other element) to the exhaust housing 14. Fig. Figure 1 shows that the fastening device 20 fastens indirectly. The fastening device 20 secures the hood part 28 with an outlet, which in turn can be attached to the exhaust housing 14.

[0053] The assembly 18 (or just the hood part 28) can be removed from the exhaust housing 14 using the fastening device 20. Either the heating element 22 is removed along with the assembly, or the heating element 22 remains attached to the exhaust housing, for example, by means of the through-passage part 26. In both alternatives, the heating element 22 is easily accessible. The heating element 22 can be replaced (non-destructively) by the through-passage part 26. This applies to both alternatives mentioned above: removing the heating element 22 with the assembly 18 or leaving the heating element 22 in place. A new heating element can then be installed in the through-passage part 26. Afterward, the assembly 18 can be reattached to the exhaust housing 14. The heating element 22 can also be attached to the through-passage part 26 by means of a further fastening device (not shown in the figure).

[0054] Fig. Figure 2 shows a cross-section of another assembly 18 in an exhaust aftertreatment device 10. The exhaust aftertreatment device 10 in Fig. Figure 2 shows an alternative to the exhaust aftertreatment device 10 in Fig. 1. Not all the same characteristics exist between Fig. 1 and Fig. Section 2 is repeated. Here, differences are primarily described.

[0055] The opening 40 runs in a ring shape around the heating element 22. Thus, the exhaust gas flow 38 also flows through the opening 40 around the heating element 22 in all circular segments (after it has flowed through the heating element 22).

[0056] An electrode 42 is shown, which supplies the heating element 22 with electrical current. The electrode 42 can be installed in the assembly 18 such that either the heating element 22 can be easily separated from the electrode 42, or the electrode 42 can be easily separated from the rest of the assembly 18. If the heating element 22 can be easily separated from the electrode 42, the heating element 22 can be connected to the electrode 42 by means of a plug connection, a push button, a screw connection, a bolt and pin connection, a clamp connection, or spring contacts. In some embodiments, the electrode 42 can hold and / or support the heating element 22. The electrode 42 can serve to secure the heating element 22. The electrode 42 can supply the heating element 22 with power. The electrode 42 is electrically insulated from the housing element 24 to prevent an electrical short circuit.It is preferably integrated in a gas-tight manner to prevent leakage to the outside. If the heating element 22 needs to be replaced, the following options are available: The heating element 22 is replaced together with the electrode 42 and the housing element 24. The other components of the exhaust system can then continue to be used without any further action. Alternatively, a detachable connection is provided between the electrode 42 and the heating element 22, for example, a screw (in ). Fig. 2 not shown, but in Fig. 3a and Fig. (as shown in Figure 3b), so that only the heating element 22 is replaced and the electrode 42 can continue to be used together with the housing element 24. In another alternative, the electrode 42 is permanently connected to the heating element 22. A passage through a wall of the housing element 24 is achieved, for example, by a screw connection.

[0057] Furthermore, it shows Fig. 2 a detachable connection 72 (for example, a clamp). The detachable connection 72 holds the hood part 28 to the exhaust housing 14. Furthermore, it shows Fig. 2 a holder 74 (dashed lines). The holder 74 can be a mechanical / fixed connection between the heating element 22 and the housing element 24. Furthermore, it shows Fig. 2 a metal housing 76. The metal housing 76 can be configured to accommodate the substrate (and / or the exhaust aftertreatment element 16).

[0058] A separation between the inlet to the heating element 22 and the outlet is in Fig. The passage section 26 is shown in a conical shape. It can be a cone and / or cone-shaped. In this illustration, the cone is fixedly connected to the metal housing 76 of the exhaust aftertreatment element 16. However, it is not fixedly connected to the heating element 22, so that the latter, together with the housing element 24, can be removed or disassembled after loosening the clamp. The connection between the heating element 22 and the housing element 24 is achieved here by retaining connecting elements, which can be, for example, narrow struts. Thus, sufficient cross-sectional area remains between the heating element 22 and the metal housing 76 for the exhaust gas to flow past. This is essentially the connection between the heating element 22 and the housing element 24 in the passage section 26.

[0059] Fig. Figure 3a shows a view of another assembly in an exhaust aftertreatment device 10. The exhaust aftertreatment device 10 in Fig. Figure 3a shows an alternative to the exhaust aftertreatment devices 10 in Fig. 1 and Fig. 2. Not all the previous figures share the same characteristics. Fig. Section 3a is repeated. Here, differences are mainly described. Fig. Figure 3b shows a cross-section of an assembly in an exhaust aftertreatment device 10. Fig. Figure 3b shows the same exhaust aftertreatment device 10 as Fig. 3a. Thus, Fig. 3a and Fig. 3b is described together here.

[0060] The exhaust gas flow 38 flows through the opening 40 (of an inlet 46 or inlet pipe 46) into the cavity 34 (through an inlet hood 48 of the hood part 28). There, the exhaust gas flow 38 is altered by less than 180° as in Fig. 2 is shown, diverted by approximately 45° and flows through the heating element 22. Thus, the exhaust gas flow direction of the heating element 22 runs from left to right. The wall 30 is positioned opposite the exhaust gas flow direction to the heating element 22 (since the wall 30 is enclosed by the hood part 28, these reference symbols point to the same in Fig. 3b). After the heating element 22, the exhaust gas flow 38 flows into the exhaust gas aftertreatment element 16. A reverse flow is possible. The shape of the hood part 28 allows easy access to the installed assembly.

[0061] The fastening device 20 of the Fig. 3a and Fig. 3b includes screws. By loosening these screws, assembly 18 can be removed. The heating element 22 can then be easily inspected and / or replaced in the removed assembly 18. Reassembly is also easily possible using the screws.

[0062] The heating element 22 is attached to the hood part 28 by means of a flange 44. This also simplifies the replacement of the heating element 22.

[0063] Fig. Figure 4 shows a method 50 for using the assembly 18. The method 50 for using the assembly 18 comprises several steps 52 to 58. In step 52, exhaust gas is heated, which flows through the heating element 22, preferably in the exhaust gas flow direction (38). In step 54, the gas flow direction (exhaust gas stream 38) of the exhaust gas in the cavity 34 is redirected. Furthermore, the method 50 can comprise either step 56 or step 58. In step 56, the heated, redirected exhaust gas is discharged from the cavity 34 via a free area (opening 40) of the passage section 26 (for example, as in the system in Figure 4). Fig. 2 to be seen), preferably after redirection by 180°. In step 58, the exhaust gas, which has not yet been redirected and is still unheated, is fed into the cavity 34 via a further passage (opening 40) (for example, as in the system in Fig. 3a and Fig. 3b can be seen).

[0064] Fig. Figure 5 shows a method 60 for replacing a heating element 22 in the exhaust aftertreatment device 10. The method 60 comprises several steps 62 to 66. In step 62, the assembly 18 is removed from the exhaust housing 14. In step 64, the heating element 22 is replaced, preferably non-destructively, in the assembly 18. In step 66, the assembly 18 is reassembled on the exhaust housing 14.

[0065] The Fig. Figures 6a to 6c show exemplary exhaust aftertreatment systems, depicted here in boxes formed by dashed lines. The exhaust aftertreatment systems shown may include and / or consist of an exhaust aftertreatment device 10 as described above. The exhaust aftertreatment systems of Fig. Sections 6a to 6c are shown schematically, illustrating the sequence of individual components in the order in which the exhaust gas flows through them (functional flow directions from left to right). The exhaust gas aftertreatment systems Fig. Figures 6a to 6c, for example, do not show the diversion in cavity 34 through wall 30. However, diversions as described above are possible. Thick arrows in the Fig. Figures 6a to 6c each show the injection of a reducing agent into a mixer 80. The mixer 80 can be an exhaust gas mixing device.

[0066] Fig. Figure 6a shows an exemplary sequence of elements through which the exhaust gas passes in the direction of flow, namely: first through the electric heating element 22, then through the catalyst 78 (for example, a diesel oxidation catalyst), then through the exhaust aftertreatment element 16, then through the mixer 80, then through the device for selective catalytic reduction 82.

[0067] Fig. Figure 6b shows another exemplary sequence of elements through which the exhaust gas passes in the direction of flow, namely: first through the catalyst 78 (for example, a diesel oxidation catalyst), then through the exhaust aftertreatment element 16, then through the electric heating element 22, then through the mixer 80, then through the device for selective catalytic reduction 82.

[0068] Fig.Figure 6c shows another exemplary sequence of elements through which the exhaust gas passes in the direction of flow, namely: first through the catalyst 78 (for example, a diesel oxidation catalyst), then through the exhaust aftertreatment element 16, then through the mixer 80, then through the electric heating element 22, and then through the device for selective catalytic reduction 82.

[0069] The assembly described here is shaped and mounted in such a way that a mechanic can easily access the assembly and the heating element it contains. This allows for simple, quick, cost-effective, and non-destructive testing and / or replacement of the heating element. These heating elements are installed and maintained in large numbers, particularly in passenger cars and trucks. Therefore, even a small improvement in this area can have a significant impact. If even a small amount of time and money is saved during each maintenance check, this adds up over the large number of maintenance tasks performed on passenger cars and trucks.

[0070] The invention has been described with reference to preferred embodiments, whereby the individual features of the described embodiments can be freely combined and / or exchanged, provided they are compatible. Likewise, individual features of the described embodiments can be omitted if they are not essential. Numerous modifications and embodiments are possible and obvious to a person skilled in the art without departing from the inventive concept. Reference symbol list 10 Exhaust aftertreatment device 12 Heating system 14 Exhaust housings 16 Exhaust aftertreatment element 18 assembly 20 Fastening device 22 electric heating element 24 Housing element 26 through section 28 Hood part 30 wall 32 side wall 34 Cavity 36 Exhaust gas mixing element 38 Exhaust gas flow 40 Opening 42 electrode 44 flange 46 Inlet or inlet pipe 48 Entrance hood 50, 60 procedures 72 Detachable Connections 74 holders 76 metal cases 78 Catalyst or diesel oxidation catalyst (DOC) 80 mixers 82 Device for selective catalytic reduction (SCR)

Claims

[1] An assembly (18) for an exhaust aftertreatment device (10) comprising the following: an electric heating element (22) with an exhaust gas flow direction (38); a housing element (24) which is designed to accommodate the electrical heating element (22) in an interchangeable manner; wherein the housing element (24) has a through-pass (26) in which the heating element (22) is arranged; wherein the housing element (24) has a hood part (28), wherein the hood part (28) has a wall (30) in or against the exhaust gas flow direction (38), and wherein a cavity (34) is formed between the wall (30) and the heating element (22). [2] The assembly (18) according to claim 1, wherein the housing element (24) is configured to accommodate the electrical heating element (22) in a non-destructively replaceable manner. [3] The assembly (18) according to claim 1 or 2, wherein the housing element (24) is configured to redirect exhaust gas flowing in through the heating element (22) into the cavity (34). [4] The assembly (18) according to one of the preceding claims, wherein a cross-section of the heating element (22) is smaller than a cross-section of the through-pass part (26). [5] The assembly (18) according to claim 4, wherein the cross-section of the heating element (22) comprises at least 50%, 30 to 70%, or 50 to 60% of the area of ​​the cross-section of the through-part. [6] The assembly (18) according to claim 4 or 5, wherein the heating element (22) is positioned in the passage part (26) such that an area of ​​the passage part (26) which is not covered by the heating element (22) remains free. [7] The assembly according to claim 6, wherein the area has an opening (40). [8] The assembly (18) according to one of the preceding claims, wherein the heating element (22) is a heating disc; and / or wherein the heating element (22) and the through-pass part (26) each have a round cross-section. [9] The assembly (18) according to one of the preceding claims, wherein the heating element (22) is positioned centrally in the passage part (26) and wherein a free area of ​​the passage part (26) is annular. [10] The assembly (18) according to claim 1 or 2, wherein the hood part (28) is a cover; and / or wherein the housing element (24) has a further passage part which is separate from the passage part (26). [11] The assembly (18) according to one of the preceding claims, wherein the housing element (24) further comprises a fastening part which is configured to fasten the assembly (18) to an exhaust housing (14) of the exhaust aftertreatment device (10) by means of at least one of the following: screw, clamp, flange and threaded connection. [12] A heating system (12) for an exhaust gas aftertreatment device (10) comprising the following: the assembly (18) according to any one of claims 1 to 11; and a fastening device (20) which is designed to fasten the assembly (18) to an exhaust housing (14) of the exhaust aftertreatment device (10) by means of at least one of the following: screw, clamp, flange, thread and welded joint. [13] An exhaust aftertreatment device (10) comprising the following: a heating system (12) according to claim 12; and an exhaust housing (14) with at least one Exhaust aftertreatment element (16). [14] The exhaust aftertreatment device (10) according to claim 13, wherein the at least one exhaust aftertreatment element (16) is a diesel particulate filter, a catalyst and / or an injector. [15] The exhaust aftertreatment device (10) according to claim 13 or 14, again depending on claim 8 or 9, wherein the hood part (28) is attached to the exhaust housing (14) in such a way that a cross-section of the exhaust housing (14) overlaps with a cross-section of the heating element (22). [16] The exhaust aftertreatment device (10) according to claim 15, wherein the hood part (28) is further attached to the exhaust housing (14) in such a way that the heating element (22) closes off the exhaust housing (14). [17] A method (50, 60) for using the assembly (18) according to any one of claims 1 to 11, comprising the following: Heating (52) of exhaust gas flowing through the heating element (22); and redirecting (54) a gas flow direction of the exhaust gas in the cavity (34). [18] The method (50, 60) according to claim 17, wherein the step of heating (52) exhaust gas flowing through the heating element (22) takes place in the exhaust gas flow direction (38). [19] The method (50, 60) according to claim 17 or 18, further comprising: Discharge (56) of the heated, redirected exhaust gas via a free area of ​​the passage part (26) from the cavity (34); or The exhaust gas, which has not yet been diverted and is still unheated, is directed into the cavity (34) via a further passage section. [20] The method (50, 60) according to claim 19, wherein the step of diverting (56) is carried out after redirection by an angle of 45° to 270°, from 90° to 270°, from 100° to 270° or by at least 180°. [21] A method (60) for replacing a heating element (22) in the exhaust aftertreatment device (10) according to any one of claims 13 to 16, comprising the following: Disassembly (62) of the assembly (18) from the exhaust housing (14); Replacing (64) the heating element (22) in the assembly (18); and Reassembling (66) the assembly (18) on the exhaust housing (14). [22] The method according to claim 21, wherein the step of replacing (64) the heating element (22) in the assembly (18) is non-destructive.

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