Connection unit for connecting an electrical supply line to a connection element of a heated exhaust system

Description

[0001] The present invention relates to a connection unit for detachably connecting an electrical supply line to a connection element of a heated exhaust system.

[0002] To quickly bring an exhaust aftertreatment unit, such as a particulate filter, catalytic converter (especially an oxidation catalyst or SCR catalyst), located in the exhaust system of a vehicle's internal combustion engine, to a temperature suitable for the exhaust aftertreatment process, particularly during the start-up phase of combustion, it is known to equip such exhaust aftertreatment units with electrically operated heating devices. These can, for example, be designed as an exhaust gas heater with a heating element located upstream of such an exhaust aftertreatment unit. This heating element heats the exhaust gas flowing towards the aftertreatment unit, and the heat absorbed in the exhaust gas is transferred to the exhaust aftertreatment unit located downstream.

[0003] To connect such heating devices to a source of electrical energy, generally a battery or on-board electrical system in a vehicle, connection elements are provided on the exhaust system component housing such a heating device. These connection elements allow for the connection of electrical supply lines. The connection of these supply lines to the corresponding connection elements is made on the outer surface of the exhaust system component housing the heating device, which is generally exposed to the environment. Therefore, the area where this connection is made is subject to environmental influences.

[0004] From EP 0 739 152 A1, a connection unit with a connection unit housing is known, which forms a substantially rectangular structure with the connection element receiving area and the supply line receiving area, as well as a connection element also designed with a substantially rectangular structure. In its section extending substantially within the supply line receiving area, the connection element is connected to a supply line extending into the supply line receiving area in the second axial end region of the supply line receiving area.With its section extending essentially within the connection element receiving area, the connection element protrudes from the connection element receiving area in the region of its second axial connection element receiving area end area from the connection unit housing and extends through an opening in a metal housing of a catalyst in order to contact an electric heater arranged in the metal housing.

[0005] From EP 3 229 599 A1, a connection unit according to the preamble of claim 1 is known, in which a first housing part is fixed to an outer circumferential side of an exhaust gas routing component of an exhaust system by welding in an area in which a connection element provided on an exhaust gas routing component projects outwards. A cap-like second housing part of the connection unit, constructed of electrically insulating material, is fixed to the first housing part by screwing and thus covers the connection element and a supply line electrically conductively fixed to the connection element by screwing.

[0006] From JP 2017 101642 A, a connection unit is known in which a connection unit housing made up of several parts is fixed to an edge area projecting radially outwards and surrounding a contact opening in an exhaust gas duct component and is thereby carried on the exhaust gas duct component.

[0007] The object of the present invention is to provide a connection unit for the detachable connection of an electrical supply line to a connection element of a heated exhaust system, with which, in a structurally simple design, a reliable shielding of the area in which an electrical connection between a supply line and a connection element is established is ensured.

[0008] According to the invention, this problem is solved by a connection unit for detachably connecting an electrical supply line to a connection element of a heated exhaust system according to claim 1, comprising a connection unit housing with a connection element receiving area extending in the direction of a first housing axis and a supply line receiving area extending in the direction of a second housing axis, wherein the connection element receiving area is open in a first axial connection element receiving area end area for receiving a connection element projecting from an exhaust system and is closed in a second axial connection element receiving area end area.wherein the supply line receiving area is open in a first axial supply line receiving area end area to the connection element receiving area and is open in a second supply line receiving area end area to receive an electrical supply line.

[0009] To allow access to the area where the electrical connection between a terminal element and an associated supply line is established, the terminal element receiving area at the second axial terminal element receiving area end area is closed off by a cover.

[0010] In order to provide both electrical and thermal insulation between the connection unit housing and the connection element, a first insulating element is arranged in the connection element receiving area, supporting the connection unit housing with respect to a connection element to be received in the connection element receiving area.

[0011] The connection unit housing, which encapsulates the two components to be electrically connected, i.e., the connection element and the supply line, shields the area in which the electrically conductive connection is made from the outside against environmental influences, so that in particular the risk of a short circuit caused by splashing water or the like is avoided.

[0012] In a design that is easy to implement even with a comparatively complex shape of the connection unit housing, it is proposed that the connection unit housing be constructed with two housing shells connected to each other in a connecting edge area, wherein each housing shell has a first housing shell section to provide the connection element receiving area and a second housing shell section to provide the supply line receiving area.

[0013] For reasons of mechanical strength and heat resistance, the connection unit housing can be made at least partially of sheet metal material.

[0014] In order to achieve a reliable shielding effect in the area adjacent to the outer circumference of an exhaust system, it is proposed that the connection unit housing in the first axial connection element receiving area end area has an exhaust system connection edge projecting radially outwards with respect to the first housing axis, with an exhaust system connection surface that surrounds the first housing axis in a ring-like manner and is to be positioned facing a counter-connection surface of an exhaust system.

[0015] For a structurally simple design of the connection unit housing, the exhaust system connection surface can lie in a plane orthogonal to the first housing axis.

[0016] Particularly when an exhaust system component, from which an electrically connected terminal protrudes, is tubular and thus has a curved outer circumferential surface, it is advantageous for achieving good shielding if the exhaust system connection surface is curved, preferably about an axis of curvature orthogonal to the first housing axis. This axis of curvature can, for example, correspond to a longitudinal center axis of the tubular exhaust system component.

[0017] Preferably, the cover is held on the connection unit housing by a positive fit, so that it can be easily and repeatedly removed from or attached to the connection unit housing to establish or disconnect the connection.

[0018] Since the insulating element and the connection unit housing are generally made of different materials, it is proposed that the first insulating element be held to the connection unit housing by positive locking.

[0019] To create a support interaction with respect to the connecting element, the first insulating element can have a connecting element receiving opening.

[0020] If the first insulating element is made of ceramic material, it provides excellent electrical insulation, and therefore excellent thermal insulation. Other materials, such as mica, can also be used to construct such an insulating element.

[0021] In order to introduce electrical and thermal insulation between the connection unit housing and the supply line, it is proposed that a second insulating element be arranged in the supply line receiving area to support the connection unit housing with respect to a supply line to be received in the supply line receiving area.

[0022] Here too, it is advantageous for the use of different materials if the second insulating element is held to the connection unit housing by a positive fit. The second insulating element can have a supply line opening for support against the connection element. The second insulating element can also be made of ceramic material or a similar material, such as mica.

[0023] For a compact design of the connection unit, it is proposed that the second housing axis be essentially orthogonal to the first housing axis.

[0024] The present invention further relates to an exhaust system for an internal combustion engine, comprising an exhaust gas routing component, at least one connection element carried on the exhaust gas routing component for connecting an electrical supply line and, in association with the at least one connection element, a connection unit constructed according to the invention for connecting the electrical supply line associated with the at least one connection element to this termination element.

[0025] To establish electrical contact between the connection element and the supply line inside the connection unit housing, the at least one connection element can be received in the connection element receiving area of ​​the connection unit associated with that connection element, and the supply line associated with the at least one connection element can be received in the supply line receiving area of ​​the connection unit associated with that connection element such that one end of this supply line extends into the connection element receiving area and is electrically connected to the connection element. The electrical contact is thus essentially established in the connection element receiving area.

[0026] For an easy-to-implement, yet stable electrical connection, a connecting eyelet can be provided at the connection end of the supply line, which is pushed onto the connection element and fixed to it by screwing.

[0027] To ensure stable mounting of the connection unit on the exhaust system, it is proposed that the connection unit be supported by the first insulating element with respect to the exhaust system, preferably with respect to the connection element. In particular, it can be provided that the first insulating element is held on the exhaust system by means of a screw device that secures the supply line to the connection element.

[0028] The exhaust system connection surface can be opposite a curved outer circumferential surface of the exhaust system component that provides the counter-connection surface and can thus be adapted to the curved outer circumferential surface of the exhaust system component.

[0029] In an alternative design, it can be provided that the exhaust system connection surface is opposite the uncurved counter-connection surface on the connection element or on the exhaust guide component.

[0030] The present invention is described in detail below with reference to the accompanying figures. These show: Fig. 1 a sectional view of an exhaust system with a connection unit for connecting a supply line to a connection element of the exhaust system; Fig. 2 one of the Fig. 1 corresponding representation of an alternative design; Fig. 3 a top view of the connection unit of the Fig. 1 in direction III in Fig. 1 .

[0031] The Fig. 1 Figure 1 shows a first embodiment of a connection unit, generally designated 10, with which an electrical supply line 12 can be connected to a connection element 14 of an exhaust system, generally designated 16. The exhaust system 16 can comprise a pipe-like exhaust gas routing component 18, in which exhaust gas flows towards an exhaust gas treatment unit, for example a particulate filter, an oxidation catalyst or an SCR catalyst. In The exhaust gas routing component 18 can be equipped with an electrically operated heating device to heat the exhaust gas flowing towards the exhaust gas treatment unit or the exhaust gas treatment unit itself. This heating device can include a heating conductor which heats up when an electrical voltage is applied and thus emits heat to its surroundings. The two terminal ends of the heating conductor are each electrically connected to a connection element 14 mounted on the exhaust gas routing component 18. Each such connection element 14 can, for example, comprise a sheath element 20, which is gas-tightly fixed to the exhaust gas routing component 18, for example by welding, and a conductor element 22 held therein in an electrically insulated manner. The end 24 of the conductor element 22, which projects outwards beyond the exhaust gas routing component 18 or the sheath element 20, is to be electrically connected to the supply line 12.

[0032] For this purpose, the supply line 12 has a connecting eyelet 28 at a connection end 26, which is pushed over the externally threaded end 24 of the conductor element 22 and is fixed to it on the connection element 14 by a screw element 30, in the illustrated embodiment a nut, in the manner described below to establish the electrical connection.

[0033] The connection unit 10 comprises a connection unit housing 32, which in the illustrated embodiment is designed with two housing shells 34, 36, each constructed as sheet metal forming parts. The two housing shells 34, 36, which are complementary to each other or essentially mirror-symmetrical, together provide a connection element receiving area 38 extending in the direction of a first housing axis G 1 and a supply line receiving area 40 extending along a second housing axis G 2. For this purpose, each of the two housing shells 34, 36 has a first housing shell section 34', 36' for providing the connection element receiving area 38 and a second housing shell section 34", 36" for providing the supply line receiving area 40. The connection element receiving area 38 and the supply line receiving area 40, respectively, are connected by a first housing shell section 34', 36' for providing the connection element receiving area 38 and a second housing shell section 34", 36", for providing the supply line receiving area 40.whose respective longitudinal axes provided by the housing axes G 1 , G 2 are preferably arranged essentially orthogonally to each other, so that the connection unit housing 32 basically has an approximately rectangular shape.

[0034] The two housing shells 34, 36, provided as sheet metal forming parts, can be firmly connected to each other in a connecting edge area 42, where they adjoin each other, for example by flanging and / or by material joining, i.e. for example by welding.

[0035] At a first axial connection element receiving area end region 44, the connection unit housing 32 or the connection element receiving area 38 is axially open to receive the connection element 14 therein. In this first axial connection element receiving area end region 44, an exhaust system connection edge 46 projecting radially outwards with respect to the first housing axis G 2 is provided on the connection unit housing 32, with an exhaust system connection surface 50 facing an outer circumferential surface 48 of the exhaust system component 18 or the exhaust system 16. In the case of a tubular, i.e., substantially circular, design of the exhaust system component 18, the connection edge 46 is preferablyThe exhaust system connection surface provided thereon, which basically surrounds the first housing axis G 1 in a ring-like manner, is curved about an axis of curvature K, whereby this axis of curvature K can essentially correspond to the longitudinal center axis of the exhaust system component 18 and thus also provides the axis of curvature of the outer circumferential surface of the exhaust system component 18, which provides a counter-connection surface 52 in the area of ​​the connection unit housing 32. Thus, a close connection of the connection edge 46 to the exhaust system component 18 is achieved when the connection unit housing 32 is fixed to the exhaust system 16, whereby in this state the connection edge 46 can, for example, touch the exhaust system component 18 or leave a small, gap-like space between it and the exhaust system component 18.

[0036] At a second axial connection element receiving area end region 54, the connection element receiving area 38 is closed off by a cover 56, which is also made of sheet metal, for example. The cover 56 can be fixed to the connection unit housing 32, for example by positive locking, in particular by snap-fit, so that it can be removed from and reattached to the connection unit housing 32 for repeated establishment and disconnection of the electrically conductive connection between the supply line 12 and the connection element 14.

[0037] The supply line receiving area 40 is open to the connection element receiving area 38 in a first axial supply line receiving area end area 58. In a second axial supply line receiving area end area 60, the supply line receiving area 40 or the connection unit housing 32 forms a feedthrough 62 adapted to the outer dimensions of the supply line 12, so that in this area a connection of the connection unit housing 32 to the supply line 12 is realized that is essentially sealed against the ingress of splashing water or contaminants.

[0038] In the connection element receiving area 38 of the connection unit housing 32, a ring-shaped first insulating element 64, for example made of ceramic material, is arranged. This is held in a form-fitting manner on the connection unit housing 32 by two axially formed, bead-like indentations 66, 68 on either side of it, so that a stable connection between these two components is achieved despite the different construction materials for the first insulating element 64 and the connection unit housing 32. The conductor element 22 of the connection element 14 passes through a connection element receiving opening 70 in the first insulating element 64. The first insulating element 64 is axially supported on the connection element 14, for example by the sheathing element 20 thereof.The connecting eyelet 28 is pushed onto the section of the conductor element 22 that projects beyond the first insulating element 64 and pressed against the first insulating element 64 by the screw element 30, thereby pressing the latter against the connecting element 14, or more generally, the exhaust system 16, and thus holding the connecting unit 10 in a defined position relative to the exhaust system 16. As already mentioned, in this state the end edge 46 can either rest against the outer circumferential surface 48 of the exhaust system component 18 or have a gap-like distance from this outer circumferential surface.

[0039] A second insulating element 72 is received in the supply line receiving area 40. This element is also held in place by a positive fit between two corrugated indentations 74, 76 on the connection unit housing 32 and provides a supply line receiving opening 78 through which the supply line 12 extends and is thus held in relation to the connection unit housing 32 in the length range passing through the supply line receiving area 40.

[0040] The two insulating elements 64, 72 provide stable electrical and thermal insulation to the connection unit 10 with respect to the connection element 14 and the electrically conductive supply line 12 connected to it. Therefore, any unavoidable heating of the connection element 14 during operation, and consequently of the supply line 12, does not lead to excessive heating of the connection unit 10.

[0041] An alternative design option is in Fig. 2 The structure of connection unit 10 is shown. In this diagram, the structure basically corresponds to the structure described above, so reference can be made to those explanations.

[0042] A base 80 providing the counter-connection surface 52 is provided in association with the connection element 14. This can, for example, form part of the connection element 14, in particular of the sheathing element 20 thereof, and thus be integrally formed or connected, or alternatively, it can also be provided on the exhaust gas routing component 18.

[0043] The counter-connection surface 52 provided at the base 80 surrounds the first housing axis G 1 in a ring-like manner and is essentially orthogonal to it. Correspondingly, the exhaust system connection surface 50 provided at the connection edge 46 is also essentially orthogonal to the first housing axis G 1, so that, as in Fig. 2 shown, which is opposite the counter-connection surface 52 with a small, slit-like distance or is supported on it.

[0044] Due to the essentially orthogonal orientation of the exhaust system connection surface 50 with respect to the first housing axis G 1, the construction of the connection unit housing 32 or of the two housing shells 34, 36 which essentially provide it is easy to implement.

[0045] The connection unit constructed according to the invention shields the area where a supply line is electrically connected to a connection element of an exhaust system from external environmental influences, particularly splashing water. The risk of an electrical short circuit caused by splashing water is thus eliminated. Furthermore, the risk of excessive corrosion in the area where the supply line is connected to an associated connection element of the exhaust system is largely eliminated, so that even after extended periods of operation, the connection unit according to the invention provides access to this connection area, allowing the supply line to be electrically or mechanically decoupled from the associated connection element.The risk that, during cleaning or maintenance work with the heating device activated, a connection element might be accidentally touched or that a short circuit to one of the connection elements or between the two connection elements of a heating device might be created by a tool, does not exist due to the sheathing of this area of ​​the electrical connection realized by the termination unit constructed according to the invention.

[0046] Alternatively or in addition to providing thermal and electrical insulation by means of the two insulating elements, it is possible to coat the inside of the connection unit housing, at least in some areas, with an electrically insulating coating, for example a ceramic coating, in order to avoid direct physical contact between the construction material of the connection unit housing, e.g. a sheet metal material, and the supply line or the connection element.

[0047] In the connection unit according to the invention, as an alternative to the essentially straight-line design of the connection element receiving area or the supply line receiving area shown in the figures, at least one of these two receiving areas can be curved and thus extend along a curved longitudinal axis, wherein such a curved receiving area has the two axial end areas described above.

Claims

1. A connection unit for the connection of an electrical supply line (12) to a connection element (14) arranged protrudingly at a heatable exhaust gas system (16), comprising a connection unit housing (32) having a connection element receiving region (38) extending in the direction of a first housing axis (G1) and a supply line receiving region (40) extending in the direction of a second housing axis (G2), wherein the connection element receiving region (38) has a first axial connection element receiving region end region (44) and a second axial connection element receiving region end region (54), wherein the connection element receiving region (38) is open in its first axial connection element receiving region end region (44) for receiving the connection element (14) protruding from the exhaust gas system (16) and is closed off in its second axial connection element receiving region end region (54), wherein the supply line receiving region (40) is open to the connection element receiving region (38) in a first axial supply line receiving region end region (58) and is open in a second supply line receiving region end region (60) for receiving an electrical supply line (12), characterized in that the connection element receiving region (38) is closed off in the second axial connection element receiving region end region (54) by a cover (56), and in that there is arranged in the connection element receiving region (38) a first insulating element (64) which supports the connection unit housing (32) with respect to the connection element (14) that is to be received in the connection element receiving region (38) and is arranged protrudingly at the exhaust gas system (16).

2. The connection unit as claimed in claim 1, characterized in that the connection unit housing (32) is constructed with two housing shells (34, 36) connected together in a connection edge region (42), wherein each housing shell (34, 36) has a first housing shell portion (34', 36') for providing the connection element receiving region (38) and a second housing shell portion (34", 36") for providing the supply line receiving region (40), or / and in that the connection unit housing (32) is constructed at least partially from sheet-metal material.

3. The connection unit as claimed in one of the preceding claims, characterized in that the connection unit housing (32) has in the first axial connection element receiving region end region (44) an exhaust gas system connection edge (46) which protrudes radially outwards with respect to the first housing axis (G1) and has an exhaust gas system connection surface (50) which surrounds the first housing axis (G1) in an annular manner and is to be positioned facing a counter connection surface (52) of an exhaust gas system (16), preferably wherein the exhaust gas system connection surface (50) lies in a plane orthogonal to the first housing axis (G1) or the exhaust gas system connection surface (50) is curved, preferably about an axis of curvature (K) which is orthogonal to the first housing axis (G1).

4. The connection unit according to one of the preceding claims, characterized in that the cover (56) is held on the connection unit housing (32) by positive engagement.

5. The connection unit characterized in that the first insulating element (64) is held on the connection unit housing (32) by positive engagement, or / and in that the first insulating element (64) has a connection element receiving opening (70), or / and in that the first insulating element (64) is constructed with ceramics material.

6. The connection unit as claimed in one of the preceding claims, characterized in that there is arranged in the supply line receiving region (40) a second insulating element (72) which supports the connection unit housing (32) with respect to a supply line (12) that is to be received in the supply line receiving region (40).

7. The connection unit as claimed in claim 6, characterized in that the second insulating element (72) is held on the connection unit housing (32) by positive engagement, or / and in that the second insulating element (72) has a supply line receiving opening (78), or / and in that the second insulating element (72) is constructed with ceramics material.

8. The connection unit as claimed in one of the preceding claims, characterized in that the second housing axis (G2) is substantially orthogonal to the first housing axis (G1).

9. An exhaust gas system for a combustion engine, comprising an exhaust gas routing component (18), at least one connection element (14), carried on the exhaust gas routing component (18), for the connection of an electrical supply line (12) and, in association with the at least one connection element (14), a connection unit (10) as claimed in one of the preceding claims for the connection of the electrical supply line (12) associated with the at least one connection element (14) to that connection element (14).

10. The exhaust gas system as claimed in claim 9, characterized in that the at least one connection element (14) is received in the connection element receiving region (38) of the connection unit (10) associated with that connection element (14), and in that the supply line (12) associated with the at least one connection element (14) is received in the supply line receiving region (40) of the connection unit (10) associated with that connection element (14) in such a manner that a connection end (26) of that supply line (12) extends into the connection element receiving region (38) and is electrically conductively connected to the connection element (14).

11. The exhaust gas system as claimed in claim 10, characterized in that there is provided at the connection end (26) of the supply line (12) a connection eyelet (28) which is pushed onto the connection element (14) and fixed thereon by screwing.

12. The exhaust gas system as claimed in one of claims 9-11, where dependent on claim 5, characterized in that the connection unit (10) is supported with respect to the exhaust gas system (16), preferably with respect to the connection element (14), by the first insulating element (64).

13. The exhaust gas system as claimed in claim 11 and claim 12, characterized in that the first insulating element (64) is held on the exhaust gas system (16) by means of a screw member (30) which fixes the supply line (12) to the connection element (14).

14. The exhaust gas system as claimed in one of claims 9-13, where dependent on claim 3, characterized in that the exhaust gas system connection surface (50) is located opposite a curved outer circumferential surface (48), providing the counter connection surface (52), of the exhaust gas routing component (18).

15. The exhaust gas system as claimed in one of claims 9-13, where dependent on claim 3, characterized in that the exhaust gas system connection surface (50) is located opposite the non-curved counter connection surface (52) on the connection element (14) or on the exhaust gas routing component (18).