Exhaust heating arrangement for an exhaust system of an internal combustion engine

Abstract

An exhaust gas heating arrangement (10) for an exhaust system of an internal combustion engine, comprising a support structure (12) and at least one heating unit (14) supported on the support structure (12) and elongated in the direction of a heating unit longitudinal axis (H), having a plurality of plate-like heating elements (16) arranged successively at a distance from one another in the direction of the heating unit longitudinal axis (H), and a support rod (32), wherein the support rod (32) of the at least one heating unit (14) has an outer cross-sectional profile that is not rotationally symmetrical at least in some regions with respect to the heating unit longitudinal axis (H), and the heating elements (16) of the at least one heating unit (14) each have a heating element receiving opening (30) with a non-rotationally symmetrical opening cross-sectional profile,so that in at least one first relative rotational position of the support rod (32) with respect to the heating elements (16) about the heating unit longitudinal axis (H), the support rod (32) is movable in the direction of the heating unit longitudinal axis (H) through the heating element receiving openings (30) of the heating elements (16), and in at least one second relative rotational position of the support rod (32) with respect to the heating elements (16) about the heating unit longitudinal axis (H), the support rod (32) passing through the heating element receiving openings (30) is essentially immovable with respect to the heating elements (16) in the direction of the heating unit longitudinal axis (H).

Description

[0001] The present invention relates to an exhaust gas heating arrangement for an exhaust system of an internal combustion engine.

[0002] DE 10 2019 107 384 A1 discloses an exhaust gas heating arrangement for an exhaust system of an internal combustion engine in a vehicle, in which a spirally wound heating unit is arranged in a tubular heating unit housing with a substantially circular circumferential contour. The heating unit comprises a jacketed heating conductor with a jacket and a heating conductor element extending within the jacket. By applying an electrical voltage to the heating conductor element, an electrical current flows through it. The heat generated due to the electrical resistance is transferred via the jacket to a heat transfer formation surrounding the jacket on its outer side. The heat transfer formation has a meandering structure with heat transfer sections arranged essentially parallel to one another, connected to one another in connecting sections, and penetrated by the jacket in a respective central region.Exhaust gas flowing through the heating unit housing in a direction substantially corresponding to the direction of a housing longitudinal axis flows along the surfaces of the heat transfer sections or connecting sections and thereby absorbs heat.

[0003] With such an exhaust gas heating arrangement, the exhaust gas flow can be heated, particularly during a start-up phase of the operation of an internal combustion engine, in which the exhaust gas emitted by the internal combustion engine has a comparatively low temperature and the exhaust gas treatment arrangements provided in the exhaust system, in particular one or more catalytic converters, also still have a comparatively low temperature, thus making it impossible to efficiently reduce the pollutant content in the exhaust gas. This allows the exhaust gas flow to be heated and heat to be introduced into system regions located downstream of the exhaust gas heating arrangement, in particular exhaust gas treatment arrangements. As a result, the period during which efficient exhaust gas purification cannot take place at the start of operation of the internal combustion engine can be significantly shortened.

[0004] DE 10 2020 130 429 A1 discloses an exhaust heating arrangement for an exhaust system of an internal combustion engine. A plurality of heating units elongated in the direction of a respective heating unit longitudinal axis, with mutually parallel heating unit longitudinal axes and spaced apart transversely to the respective heating unit longitudinal axes, are arranged on a frame-like support structure. The heating units each comprise a jacketed heating conductor elongated in the direction of the respective heating unit longitudinal axis, on the outer surface of which a heat transfer formation with a meandering structure is arranged, absorbing heat from the jacketed heating conductor.

[0005] It is the object of the present invention to provide an exhaust gas heating arrangement for an exhaust system of an internal combustion engine, with which a reliable heating of exhaust gas flowing around the exhaust gas heating arrangement is achieved with high operational reliability.

[0006] According to the invention, this object is achieved by an exhaust gas heating arrangement for an exhaust system of an internal combustion engine, comprising a support structure and at least one heating unit carried on the support structure and elongated in the direction of a heating unit longitudinal axis, with a plurality of plate-like heating elements arranged one after the other at a distance from one another in the direction of the heating unit longitudinal axis, and a support rod, wherein the support rod of the at least one heating unit has an outer cross-sectional profile that is not rotationally symmetrical at least in some regions with respect to the heating unit longitudinal axis, and the heating elements of the at least one heating unit each have a heating element receiving opening with a non-rotationally symmetrical opening cross-sectional profile,so that in at least one first relative rotational position of the support rod with respect to the heating elements about the heating unit's longitudinal axis, the support rod is movable in the direction of the heating unit's longitudinal axis through the heating element receiving openings of the heating elements, and in at least one second relative rotational position of the support rod with respect to the heating elements about the heating unit's longitudinal axis, the support rod passing through the heating element receiving openings is essentially immovable with respect to the heating elements in the direction of the heating unit's longitudinal axis.

[0007] By coordinating the shape of the support rod on the one hand and the heating element receiving openings on the other, it is possible to guide the support rod through the heating unit and thus position it within the heating unit. After moving or rotating it into the second relative rotational position, the support rod can no longer be moved in the direction of the heating unit's longitudinal axis with respect to the heating elements, but is positively connected to them and simultaneously ensures that the heating elements following one another in the direction of the heating unit's longitudinal axis are held in a defined position and at a distance from one another.

[0008] In order to ensure in particular the defined positioning of the heating elements at a distance from one another, the support rod of the at least one heating unit can comprise a body region which is elongated in the direction of the heating unit's longitudinal axis and, in at least one circumferential region, a group of heating element engagement sections which are arranged at an axial distance from one another and project radially outwards from the body region with respect to the heating unit's longitudinal axis, wherein in the support rod which passes through the heating element receiving openings and is positioned in the at least one second relative rotational position, at least one heating element engagement section is positioned between at least two, preferably all, heating elements which follow one another directly in the direction of the heating unit's longitudinal axis.

[0009] A further increased stability in the axial positioning of the individual heating elements can be achieved, for example, by providing a group of heating element engagement sections on the support rod at two circumferential regions opposite one another with respect to the longitudinal axis of the heating unit.

[0010] The non-rotationally symmetrical shape of the support rod in those axial regions in which heating element engagement sections are provided thereon can be achieved in that in at least one, preferably each group of heating element engagement sections, the heating element engagement sections are formed with a cross-sectional profile tapering in the direction radially outward away from the body region.

[0011] Furthermore, the stable positioning of the heating elements in the axial direction can be supported in that, in at least one, preferably each group of heating element engagement sections, the distance between heating element engagement sections immediately adjacent to one another in the direction of the heating unit longitudinal axis essentially corresponds to a thickness of the heating element arranged between them.

[0012] In order to enable rotation of the support rod to move it into the second relative rotational position when the support rod is correctly positioned with respect to the heating elements of the at least one heating unit in the direction of the heating unit's longitudinal axis, it is proposed that the body region of the support rod has a substantially rotationally symmetrical, preferably substantially circular, outer cross-sectional profile in length sections lying between each two heating element engagement sections arranged in the direction of the heating unit's longitudinal axis.

[0013] In order to enable the support rod with the heating element engagement sections provided thereon to pass through the heating element receiving openings provided in the heating elements, on the one hand, and to achieve stable radial mounting of the heating elements on the support rod when the support rod is positioned in the second relative rotational position, on the other hand, it is proposed that the heating element receiving openings have a central receiving opening region which is shaped to match the outer cross-sectional profile of the support rod in longitudinal sections lying axially between each two heating element engagement sections arranged one after the other in the direction of the longitudinal axis of the heating unit, and, starting from the central receiving opening region, in association with each group of heating element engagement sections, an engagement section receiving opening region which is shaped to match the outer cross-sectional profile of the support rod in the axial region of the heating element engagement sections.

[0014] For electrical contacting of the at least one heating unit, a busbar can be arranged in at least one, preferably each axial end region of the at least one heating unit, following a last heating element in the direction of the longitudinal axis of the heating unit. A busbar receiving opening, through which the support rod of the at least one heating unit passes, can be provided in the busbar in association with the at least one heating unit. A configuration in which an opening cross-sectional profile of the busbar receiving opening substantially corresponds to the opening cross-sectional profile of the heating element receiving openings of the heating elements of the at least one heating unit is particularly preferred. This also ensures a defined positioning of the support rod in a respective busbar receiving opening.

[0015] A defined relative positioning between the support rod and the busbars can be supported in that on the support rod of the at least one heating unit, in at least one, preferably each axial end region of the heating unit, in association with at least one, preferably each group of heating element engagement sections, a busbar engagement section is arranged at an axial distance from a last heating element engagement section in the direction of the longitudinal axis of the heating unit, and in that in the case of the support rod which passes through the busbar receiving opening of a respective busbar and the heating element receiving openings of the heating elements and is positioned in the at least one second relative rotational position, a respective busbar is arranged in the direction of the longitudinal axis of the heating unit between the last heating element engagement section in the direction of the longitudinal axis of the heating unit and a busbar engagement section.

[0016] In order to simultaneously ensure defined electrical contact of a respective busbar with a directly following heating element when holding the respective busbar relative to the support rod, the axial distance between each busbar engagement section and the immediately following heating element engagement section can essentially correspond to a thickness of the busbar and heating element arranged therebetween. This means that the space provided to accommodate the assembly of busbar and heating element corresponds to the entire axial thickness of this assembly, and thus the heating element and the associated busbar are held in a defined contact with one another.

[0017] For example, in at least one axial end region of the heating unit, a cross-sectional profile of at least one, preferably each, busbar engagement section can substantially correspond to a cross-sectional profile of the heating element engagement sections of the associated group of heating element engagement sections.

[0018] To prevent an electrical short circuit via the support rod, the support rod of the at least one heating unit can be constructed of electrically insulating material, preferably ceramic material. Furthermore, in particular to provide a structure with the lowest possible weight, the support rod of the at least one heating unit can be tubular. The volume provided inside a support rod constructed in this way can also be used to connect the support rod to the support structure.

[0019] For this purpose, for example, the at least one heating unit can be supported on the support structure by means of at least one connecting rod which passes through the support rod of the few heating units at least in some areas.

[0020] In a simple-to-implement design that simultaneously ensures an electrically conductive connection between the heating elements arranged successively in the axial direction, the at least one heating unit can comprise a heating conductor with a meandering structure comprising the heating elements and the connecting sections connecting them. Such a heating conductor can be produced, for example, by bending a blank made of electrically conductive flat material, in particular metal material, into the meandering structure.

[0021] In order to achieve the most uniform possible heating of the exhaust gas flow or the flow of gas flowing around the exhaust gas heating arrangement in a cross section of an exhaust gas guide component through which exhaust gas flows, it is proposed that a plurality of heating units with heating unit longitudinal axes that are essentially parallel to one another and essentially transverse to the respective heating unit longitudinal axis are provided one after the other.

[0022] In this case, the closest and most defined positioning of the heating units can be ensured by at least one, preferably each heating unit having an engagement recess open transversely to the longitudinal axis of the heating unit in at least one, preferably each heating element, and an engagement projection protruding substantially transversely to the longitudinal axis of the heating unit and opposite the at least one engagement recess with respect to the longitudinal axis of the heating unit in at least one, preferably each heating element.

[0023] The invention further relates to an exhaust system for an internal combustion engine, comprising at least one exhaust gas heating arrangement constructed according to the invention.

[0024] The present invention is described in detail below with reference to the accompanying figures. They show: Fig. 1 is a perspective view of an exhaust gas heating arrangement constructed with a plurality of heating units arranged side by side; Fig. 2 a view of the exhaust gas heating arrangement of the Fig. 1, viewed in a main exhaust gas flow direction; Fig. 3 a sectional view of the exhaust gas heating arrangement of the Fig. 2, cut along a line III-III in Fig. 2; Fig. 4 the detail IV in Fig. 3 enlarged; Fig. 5 a sectional view of the exhaust gas heating arrangement of the Fig. 2, cut along a line VV in Fig. 2; Fig. 6 is a perspective view of a support rod of an exhaust gas heating unit; Fig. 7 a side view of the support rod of the Fig. 6 in view direction VII in Fig. 6; Fig. 8 a side view of the support rod of the Fig. 6 in direction VIII in Fig. 6; Fig. 9 an axial view of the support rod of the Fig. 6 in direction IX in Fig. 6; Fig. 10 a perspective view of a busbar of the exhaust gas heating arrangement of the Fig. 2; Fig. 11 is a perspective view of a heating conductor with a meandering structure providing a plurality of heating elements; Fig. 12 a connecting rod of the exhaust gas heating arrangement of the Fig. 2; Fig. 13 a plan view of a heating element of the heating conductor of the Fig. 11, Fig. 14 the detail XIV in Fig. 5 enlarged.

[0025] In the figures, an exhaust gas heating arrangement for an exhaust system of an internal combustion engine is generally designated by 10. The exhaust gas heating arrangement 10 serves to heat gas flowing in an exhaust system of an internal combustion engine, in particular the exhaust gas emitted by an internal combustion engine, in order to thereby achieve faster heating in system regions located downstream of the exhaust gas heating arrangement 10, such as a catalytic converter or a particulate filter or the like.

[0026] The exhaust gas heating arrangement 10 comprises a frame-like or box-like support structure 12, provided for example by forming a strip-like sheet metal blank, with a Fig. 2. In the illustrated embodiment, seven heating units 14 are arranged in the interior space surrounded by the frame-like support structure 12 and through which the gas or exhaust gas can flow.

[0027] Each of the Fig. 3 and Fig. 4 more clearly visible heating units 14 is basically elongated in the direction of a heating unit longitudinal axis H. The heating units 14 arranged inside the support structure 12 are arranged with mutually parallel heating unit longitudinal axes H and transverse to these heating unit longitudinal axes H next to each other or one after the other, so that, for example, all heating unit longitudinal axes H of the heating units 14 are in a direction parallel to a main exhaust gas flow direction, which is to the plane of the drawing of the Fig. 2 can stand orthogonally, lying plane are positioned.

[0028] Each heating unit 14 comprises a plurality of plate-like heating elements 16, which are aligned substantially orthogonally to the respective heating unit longitudinal axis H and are arranged parallel to one another in the direction of the heating unit longitudinal axis H with preferably a substantially constant distance from one another. To provide this plurality of heating elements 16 following one another in the direction of the heating unit longitudinal axis H, each heating unit 14 can have a Fig. 11, which is bent from a strip-like blank into a meandering structure. In this meandering structure, the plate-like heating elements 16 are parallel to each other. Fig. 13 and Fig. 14, successive heating elements 16 are connected to one another in the direction of the heating unit's longitudinal axis H by connecting sections 20 and 22, 24, respectively, which are bent during the production of the meander-like structure. The connecting sections 20 formed at one of the lateral end regions each provide an engagement projection 26 projecting transversely to the heating unit's longitudinal axis H. At the other lateral end region, between the two connecting sections 22, 24 provided there, an engagement recess 28 is formed, which is open in the direction away from the heating unit's longitudinal axis H. The engagement recesses 28 and the engagement projections 26 are coordinated with one another in such a way that, as shown in Fig. 5 and 14, respectively, in the adjacent heating units 14, the engagement projections 26 provided on one of the heating units 14 engage in the engagement recesses 28 provided on an immediately adjacent heating unit 14. In this way, a defined positioning of the adjacent heating units 14 or the heating conductors 18 thereof is achieved, which at the same time also enables a very dense packing of the adjacent heating units 14.Since, during heating operation, current flows through the heating conductors 18 of the adjacent and interlocking heating units 14, it is advantageous, in order to avoid an electrical short circuit in the areas in which engagement projections 26 engage in engagement recesses 28, either to leave a gap between the heating conductors 18 of immediately adjacent heating units 14 or to arrange insulating material layers between the immediately adjacent heating units 14 in these areas.

[0029] A heating element receiving opening 30 is formed in each of the heating elements 16. The heating element receiving openings 30 formed in successive heating elements 16 of each heating conductor 18 in the direction of the respective heating unit longitudinal axis H are preferably of identical design and positioned congruently with one another. Fig. 13, that the heating element receiving openings 30 have an opening cross-sectional profile, which will be explained below, which is not rotationally symmetrical with respect to a respective heating element longitudinal axis H.

[0030] Each heating unit 14 further comprises a Fig. 6 to 9. The support rod 32, which is made of electrically insulating material, for example ceramic material, and / or coated therewith, has a body region 34 which is elongated in the direction of the respective heating unit longitudinal axis H. The body region 34 is preferably constructed with a rotationally symmetrical, for example essentially circular, outer cross-sectional profile. Two groups 36, 38 of heating element engagement sections 40, 42 extend from the body region 34 in regions which are diametrically opposite one another with respect to the heating unit longitudinal axis H, and are preferably arranged at the same distance from one another in the direction of the heating unit longitudinal axis H. In each of the two groups 36, 38, the immediately successive heating element engagement sections are arranged at a distance from one another which essentially corresponds to the thickness of the plate-like heating elements 16 and 18.of the heating conductor 18 in the area of ​​the plate-like heating elements 16 formed thereon.

[0031] The heating element engagement sections 40, 42 are shaped in such a way that, starting from the body region 34, they have a tapered shape in the direction away from the heating unit longitudinal axis H, so that, as in Fig. 9, in axial view, a non-rotationally symmetrical, for example approximately trapezoidal outer cross-sectional profile of the support rod 32 results in those length regions in which the heating element engagement sections 40, 42 of the two groups 36, 38, which are assigned to one another, for example, in pairs or opposite one another, are positioned.

[0032] Corresponding to this non-rotationally symmetrical shape of the support rod 32 in the axial regions of the heating element engagement sections, the heating element receiving openings 30 formed in the heating elements 16 are also formed with a central opening region 44 adapted to the rotationally symmetrical outer circumferential contour of the body region 34, to which engagement section receiving opening regions 46, 48 adjoin in opposite regions.

[0033] When assembling a respective heating conductor 14 with an associated support rod 32, the support rod 32 is first positioned in a first relative rotational position with respect to the heating conductor 18 or the heating elements 16 thereof such that the heating element engagement sections 40, 42 are aligned with the engagement section receiving opening areas 46, 48 and thus the support rod 32 can be guided through the heating conductor 18 in the direction of the heating unit's longitudinal axis H. Once the support rod 32 has been fully inserted into the heating conductor 18 or into all of the heating elements 16 thereof, the heating element engagement sections 40, 42 are positioned such that, in the direction of the heating unit's longitudinal axis H, they are each located between two directly successive heating elements 16. The support rod 32 can then be rotated about the heating unit's longitudinal axis H, for example by 90°, into a second rotational position with respect to the heating conductor 18 or the heating elements 16.the heating elements 16 thereof are rotated so that, as the . Fig. 14 illustrates that the heating element engagement sections are also rotated by 90° with respect to the engagement section receiving opening regions 46, 48 and thus each engage between two immediately adjacent heating elements 16. In this way, the heating elements 16 are held in a defined axial position and at a distance from one another. At the same time, each heating element 16 is supported in the radial direction by the shape of the central receiving opening region 40, which is adapted to the outer cross-sectional profile of the support rod 32 in the regions between the respective heating element engagement sections 40, 42. Thus, the individual heating elements 16 can move neither in the axial nor in the radial direction with respect to the support rod 32, so that a substantially fixed connection between the support rod 32 and the heating conductor 18 or heating elements 16 is achieved.

[0034] At the two axial ends of the heating units 14 or the heating conductor 18 thereof, there is a Fig. 10, is arranged on a substantially L-shaped busbar 50, 52. As shown in Fig. 10 using the busbar 50 as an example, this busbar has a busbar receiving opening 54 associated with each heating unit 14 or each support rod 32. The busbar receiving openings 54 have essentially the same shape as the heating element receiving openings 30. This allows the busbars 50, 52 to be connected to a respective support rod 32 in the same manner as is the case with the heating elements 16.

[0035] The Fig. 6 to 8 show that in the two axial end regions of the support rod 32, respective busbar engagement sections 56, 58 and 60, 62 are formed in association with the two groups 36, 38 of heating element engagement sections 40, 42. While the Fig. 7 at the right axial end region of the support rod 32 are adapted in terms of their positioning and shape to the heating element engagement sections 40, 42 of the two groups 36, 38 and are also positioned congruently with them, are on the in Fig. 7, the busbar engagement sections 60, 62 are formed on a head 64 of the support rod 32, which is shaped like a plate, for example, in the axial end region of the support rod 32 on the left.

[0036] The busbar engagement sections 56, 58 and 60, 62 provided in the two axial end regions are spaced axially from the last heating element engagement sections 40', 42' and 40", 42" of the two groups 36, 38 in the two axial end regions by an axial distance which corresponds to the thickness of the respective busbar 50, 52 in the leg 66 thereof providing the busbar receiving openings 54, plus the thickness of a respective last heating element 16' or 16" of the heating conductor 18 in the direction of the heating unit's longitudinal axis H. The assembly, each comprising a busbar 50, 52 and a respective last heating element 16', 16" in the axial direction, is thus firmly connected in the axial direction between the busbar engagement sections 56, 58 and 60, 62 and the immediately following Heating element engagement sections 40', 42' or 40" and 42".In this way, a stable electrically conductive contact between the axial end regions of a respective heating conductor 18 and the associated busbars 50, 52 can be achieved at the same time.

[0037] During assembly of the heating units 14 or the exhaust gas heating arrangement 10, the individual heating conductors 18 of the heating units 14 are positioned next to one another such that they can be covered by the busbars 50, 52 at their axial end regions. The busbar receiving openings 54 formed in the busbars 50, 52 are positioned congruently with the heating element receiving openings 30 formed in the individual heating conductors 18 or the heating elements 16 thereof. The support rods 32 are then guided through the busbars 50, 52 or the heating conductors 18 positioned therebetween in the respective first relative rotational position until the head 64 of a respective support rod 32 rests against the L-shaped leg 66 of the busbar 50.In this state, each support rod 32 extends through both busbars 50, 52 and the heating conductors 18 positioned therebetween, such that the busbar engagement sections 56, 58 are located on the side of the L-leg 68 of the busbar 52 facing away from the heating conductors 18. By rotating the support rods 32 into the respective second relative rotational position with respect to the associated heating conductors 18, the heating element engagement sections 40, 42 are positioned so as to engage between two heating elements 16. Furthermore, the busbar engagement sections 56, 58 and 60, 62 on the head 64 engage behind the L-legs 66, 68 of the busbars 50, 52 on their sides facing away from the heating conductors 18. This creates a solid connection between the support rods 32, the busbars 50, 52, and all heating conductors 18 or heating elements 16. This solid connection can then be inserted into the frame-like support structure 12.

[0038] Openings are formed in opposing frame sections 70, 72 of the support structure 18 in association with the support rods 32. The support rods 32 are tubular in design, so that after the assembly of heating units 14 and busbars 50, 52 has been inserted into the support structure 12, connecting rods 74 can be guided through the openings formed in the frame sections 70, 72 and through the tubular support rods 32 and can be firmly connected to the support structure 12 in the region of their axial ends by forming and / or by material bonding. The connecting rods 74, like the support structure 12, can be constructed of metal material, so that the firm connection can be achieved, for example, by soldering or welding.Since the support rods 32 are constructed and / or coated with electrically insulating material and since the busbar engagement sections 56, 58 or the head 64 with the busbar engagement sections 60, 62 formed thereon are positioned between each busbar 50, 52 and the respective adjacent region of the support structure 12, an electrically insulated mounting of all heating units 14 on the frame-like support structure 12 is also ensured.

[0039] After connecting all support units 14 to the support structure 12 by means of the connecting rods 74, connection units 80, 82 can be connected to the respective shorter L-legs 76, 78 of the busbars 50, 52, which penetrate the support structure 12. Connection units 80, 82 can be used to connect the axial ends of the heating conductors 18 of all heating units 14, which are thus electrically connected in parallel, to a voltage source. These connection units 80, 82 can, in particular, be passed in a gas-tight manner through an exhaust gas routing component of an exhaust system of an internal combustion engine, for example, a tubular or housing-like structure.

[0040] With the structure of an exhaust gas heating arrangement described above and shown in the figures, a structure is provided which is easy to implement and has a large number of identical parts and is therefore cost-effective to manufacture, which at the same time ensures that, through defined positioning of the heating conductors of the individual heating units and also of the individual heating elements of the individual heating conductors, on the one hand a uniform flow of gas or exhaust gas is guaranteed, and on the other hand an electrical short circuit within a respective heating conductor or between the heating conductors of different heating units is avoided.The shape of the support rods on the one hand and the heating element receiving openings that accommodate them on the other hand make it possible to position the support rods in the individual heating conductors in such a way that the defined positioning of the individual heating elements can be specified and maintained without the need to create a material bond between the support rods and the heating conductors. Forming processes to achieve a defined positioning of the heating elements using the support rods are also not required during or after inserting the support rods into the respective heating conductors.

[0041] Finally, it should be noted that, of course, deviating from the above statements or the representations contained in the figures, the heating element engagement sections or the busbar engagement sections in particular may have a different shape, and the various receiving openings may also have different shapes, which do not necessarily have to be exactly complementary to the outer cross-sectional profile of the respective support rods in the axial region of the heating element engagement sections. For example, the engagement section receiving opening areas could have an approximately rectangular or square cross-sectional profile.The body region 34 could also, for example, have an approximately square cross-sectional profile, so that when positioned in the second relative rotational position, it can be supported essentially not over extended circumferential regions, but only in edge regions in the central receiving opening region. The central receiving opening region can have or provide a substantially circular cross-sectional contour and thus be shaped to the cross-sectional contour of the body region of a respective support rod, which is equally suitable for radial support. List of reference symbols 10 Exhaust gas heating arrangement 12 Support structure 14 Heating unit 16 Heating element 16' heating element 16" heating element 18 heating conductors 20 connecting section 22 connecting section 24 connecting section 26 engagement projection 28 Recess 30 Heating element receiving opening 32 support rod 34 Body area 36 Group of heating element engaging sections 38 Group of heating element engaging sections 40 Heating element engagement section 40' heating element engagement section 40" heating element engagement section 42 Heating element engagement section 42' heating element engagement section 42" heating element engagement section 44 Opening area 46 Engagement section receiving opening area 48 engagement section receiving opening area 50 busbar 52 Busbar 54 Busbar mounting opening 56 Busbar engagement section 58 Busbar engagement section 60 busbar engagement section 62 Busbar engagement section 64 heads 66 L-legs 68 L-legs 70 frame section 72 frame section 74 Connecting rod 76 L-legs 78 L-legs 80 connection unit 82 connection unit H Heating unit longitudinal axis

Claims

[1] An exhaust gas heating arrangement (10) for an exhaust system of an internal combustion engine, comprising a support structure (12) and at least one heating unit (14) supported on the support structure (12) and elongated in the direction of a heating unit longitudinal axis (H), having a plurality of plate-like heating elements (16) arranged one after the other at a distance from one another in the direction of the heating unit longitudinal axis (H), and a support rod (32), wherein the support rod (32) of the at least one heating unit (14) has an outer cross-sectional profile that is not rotationally symmetrical at least in some regions with respect to the heating unit longitudinal axis (H), and the heating elements (16) of the at least one heating unit (14) each have a heating element receiving opening (30) with a non-rotationally symmetrical opening cross-sectional profile,so that in at least one first relative rotational position of the support rod (32) with respect to the heating elements (16) about the heating unit longitudinal axis (H), the support rod (32) is movable in the direction of the heating unit longitudinal axis (H) through the heating element receiving openings (30) of the heating elements (16), and in at least one second relative rotational position of the support rod (32) with respect to the heating elements (16) about the heating unit longitudinal axis (H), the support rod (32) passing through the heating element receiving openings (30) is essentially immovable with respect to the heating elements (16) in the direction of the heating unit longitudinal axis (H). [2] Exhaust gas heating arrangement (10) according to claim 1, characterized byin that the support rod (32) of the at least one heating unit (14) comprises a body region (34) which is elongated in the direction of the heating unit longitudinal axis (H) and, in at least one circumferential region, a group (36, 38) of heating element engagement sections (40, 42) which are arranged at an axial distance from one another and project radially outwards from the body region (34) with respect to the heating unit longitudinal axis (H), wherein in the support rod (32) which passes through the heating element receiving openings (30) and is positioned in the at least one second relative rotational position, at least one heating element engagement section (40, 42) is positioned between at least two heating elements (16) which follow one another directly in the direction of the heating unit longitudinal axis (H). [3] Exhaust gas heating arrangement (10) according to claim 2, characterized bythat at least one heating element engagement section (40, 42) is positioned between all heating elements (16) which immediately follow one another in the direction of the longitudinal axis (H) of the heating unit. [4] Exhaust gas heating arrangement (10) according to claim 2 or 3, characterized bythat a group (36, 38) of heating element engagement sections (40, 42) is provided on the support rod (32) on two circumferential regions opposite one another with respect to the longitudinal axis (H) of the heating unit, and / or that in at least one group (36, 38) of heating element engagement sections (40, 42), the heating element engagement sections (40, 42) are designed with a cross-sectional profile that tapers radially outwards away from the body region (34), and / or that in at least one group (36, 38) of heating element engagement sections (40, 42), the distance between heating element engagement sections (40, 42) that are immediately adjacent to one another in the direction of the longitudinal axis (H) of the heating unit essentially corresponds to a thickness of the heating element (16) arranged between them. [5] Exhaust gas heating arrangement (10) according to claim 4, characterized bythat in each group (36, 38) of heating element engagement sections (40, 42), the heating element engagement sections (40, 42) are designed with a cross-sectional profile that tapers radially outwards away from the body region (34), and / or that in each group (36, 38) of heating element engagement sections (40, 42), the distance between heating element engagement sections (40, 42) that are immediately adjacent to one another in the direction of the heating unit longitudinal axis (H) essentially corresponds to a thickness of the heating element (16) arranged between them. [6] Exhaust gas heating arrangement (10) according to one of claims 2-5, characterized by that the body region (34) of the support rod (32) has a substantially rotationally symmetrical outer cross-sectional profile in each longitudinal section lying between two heating element engagement sections (40, 42) arranged one after the other in the direction of the heating unit longitudinal axis (H). [7] Exhaust gas heating arrangement (10) according to claim 6, characterized by that the body region (34) of the support rod (32) has a circular outer cross-sectional profile in the length sections lying between two heating element engagement sections (40, 42) arranged one after the other in the direction of the heating unit longitudinal axis (H). [8] Exhaust gas heating arrangement (10) according to one of claims 2-7, characterized bythat the heating element receiving openings (30) have a central receiving opening region (44) which is shaped to match the outer cross-sectional profile of the support rod (32) in longitudinal sections lying axially between each two heating element engagement sections (40, 42) arranged one after the other in the direction of the heating unit longitudinal axis (H) and, starting from the central receiving opening region (44), in association with each group (36, 38) of heating element engagement sections (40, 42), an engagement section receiving opening region (46, 48) which is shaped to match the outer cross-sectional profile of the support rod (32) in the axial region of the heating element engagement sections (40, 42). [9] Exhaust gas heating arrangement (10) according to one of claims 2-8, characterized in that in at least one axial end region of the at least one heating unit (14) a busbar (50, 52) is arranged following a last heating element (16', 16") in the direction of the longitudinal axis (H) of the heating unit, and in that in association with the at least one heating unit (14) in the busbar (50, 52) a busbar receiving opening (54) through which the support rod (32) of the at least one heating unit (14) passes is provided. [10] Exhaust gas heating arrangement (10) according to claim 9, characterized by that an opening cross-sectional profile of the busbar receiving opening (54) substantially corresponds to the opening cross-sectional profile of the heating element receiving openings (30) of the heating elements (16) of the at least one heating unit (14). [11] Exhaust gas heating arrangement (10) according to claim 9 or 10, characterized bythat in each axial end region of the at least one heating unit (14) a busbar (50, 52) is arranged following a last heating element (16', 16") in the direction of the heating unit longitudinal axis (H). [12] Exhaust gas heating arrangement (10) according to one of claims 9-11, characterized bythat on the support rod (32) of the at least one heating unit (14) in at least one axial end region of the heating unit (14) in association with at least one group (36, 38) of heating element engagement sections (40, 42), a busbar engagement section (56, 58, 60, 62) is arranged at an axial distance from a heating element engagement section (40', 42', 40", 42") that is last in the direction of the heating unit longitudinal axis (H), and that when the support rod (32) passes through the busbar receiving opening (54) of a respective busbar (50, 52) and the heating element receiving openings (30) of the heating elements (16) and is positioned in the at least one second relative rotational position, a respective busbar (50, 52) is arranged in the direction of the heating unit longitudinal axis (H) between the last in the direction of the heating unit longitudinal axis (H) Heating element engagement portion (40', 42, 40", 42") and a busbar engagement portion (56, 58, 60, 62). [13] Exhaust gas heating arrangement (10) according to claim 12, characterized by that on the support rod (32) of the at least one heating unit (14) in each axial end region of the heating unit (14) in association with each group (36, 38) of heating element engagement sections (40, 42), a busbar engagement section (56, 58, 60, 62) is arranged at an axial distance from a last heating element engagement section (40', 42', 40", 42") in the direction of the heating unit longitudinal axis (H). [14] Exhaust gas heating arrangement (10) according to claim 12 or 13, characterized bythat the axial distance between each busbar engagement section (56, 58, 60, 62) and the immediately following heating element engagement section (40', 42', 40", 42") substantially corresponds to a thickness of the busbar (50, 52) arranged therebetween and of the heating element (16', 16") arranged therebetween, and / or that in at least one axial end region of the at least one heating unit (14), a cross-sectional profile of at least one busbar engagement section (56, 58) substantially corresponds to a cross-sectional profile of the heating element engagement sections (40, 42) of the associated group (36, 38) of heating element engagement sections (40, 42). [15] Exhaust gas heating arrangement (10) according to claim 14, characterized byin that in at least one axial end region of the at least one heating unit (14), the cross-sectional profile of each busbar engagement section (56, 58) substantially corresponds to the cross-sectional profile of the heating element engagement sections (40, 42) of the associated group (36, 38) of heating element engagement sections (40, 42). [16] Exhaust gas heating arrangement (10) according to one of claims 1-15, characterized by that the support rod (32) of the at least one heating unit (14) is constructed with electrically insulating material, and / or that the support rod (32) of the at least one heating unit (14) is tubular. [17] Exhaust gas heating arrangement (10) according to claim 16, characterized by that the support rod (32) of the at least one heating unit (14) is constructed with ceramic material. [18] Exhaust gas heating arrangement (10) according to one of claims 1-17, characterized bythat the at least one heating unit (14) is supported on the support structure (12) by means of at least one connecting rod (74) which passes through the support rod (32) of the at least one heating unit (14) at least in some regions. [19] Exhaust gas heating arrangement (10) according to one of claims 1-18, characterized by that the at least one heating unit (14) comprises a heating conductor (18) with a meander-like structure comprising the heating elements (16) and connecting sections (20, 22, 24) connecting them. [20] Exhaust gas heating arrangement (10) according to one of claims 1-19, characterized by that a plurality of heating units (14) are provided with heating unit longitudinal axes (H) that are substantially parallel to one another and substantially transverse to the respective heating unit longitudinal axis (H) in succession. [21] Exhaust gas heating arrangement (10) according to claim 20, characterized bythat at least one heating unit (14) has, in at least one heating element (16), an engagement recess (28) open transversely to the heating unit longitudinal axis (H), and in at least one heating element (16), an engagement projection (26) projecting substantially transversely to the heating unit longitudinal axis (H) and opposite the at least one engagement recess (28) with respect to the heating unit longitudinal axis (H). [22] Exhaust gas heating arrangement (10) according to claim 21, characterized by that each heating unit (14) has, in each heating element (16), the engagement recess (28) open transversely to the heating unit longitudinal axis (H), and in each heating element (16), the engagement projection (26) projecting substantially transversely to the heating unit longitudinal axis (H) and lying opposite the at least one engagement recess (28) with respect to the heating unit longitudinal axis (H). [23] Exhaust system for an internal combustion engine, comprising at least one exhaust gas heating arrangement (10) according to one of the preceding claims.

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