Secondary gas inlet arrangement

Abstract

Secondary gas inlet arrangement for introducing gas into an exhaust system of an internal combustion engine, comprising a tubular inlet body (28) with a circumferential wall (36) surrounding a gas receiving volume (54) and a longitudinal axis (K), wherein a gas passage opening formation (56) is provided in the circumferential wall (36) for the exit of gas from the gas receiving volume (54) into a volume (35) surrounding the circumferential wall (36), characterized in that - that the circumferential wall (36) is double-walled with an inner wall (40) and an outer wall (42), wherein a gas passage volume (57) is formed between the inner wall (40) and the outer wall (42), - that the gas passage opening formation (56) comprises inner openings (58) in the inner wall (40), wherein the gas intake volume (54) is connected to the gas passage volume (57) via the inner openings (58), - that the gas passage opening formation (56) comprises outer openings (60) in the outer wall (42), wherein the gas passage volume (57) is open to the volume (35) surrounding the circumferential wall (36) via the outer openings (60), and - that at least one inner opening (58) is not completely overlapped by an outer opening (60) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K), or / and that at least one outer opening (60) is not completely overlapped by an inner opening (58) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K).

Description

[0001] The present invention relates to a secondary gas inlet arrangement for introducing gas, in particular air, into the exhaust system of an internal combustion engine.

[0002] To quickly bring one or more exhaust gas treatment units, such as oxidation catalysts, SCR catalysts, or particulate filters, provided in the exhaust system of internal combustion engines, to the operating temperature required for a catalytic reaction at the start of operation, it is known to arrange electrically operated heating units upstream of such exhaust gas treatment units. The exhaust gas emitted by the internal combustion engine flows through these heating units. The exhaust gas absorbs heat from such a heating unit and transports it towards one or more exhaust gas treatment units located downstream.The heat provided by such heating units can be used even before an internal combustion engine starts operating to preheat one or more exhaust gas treatment units, provided that a secondary gas, generally air, is fed into the exhaust system upstream of these units. If there is no exhaust gas flow yet, the secondary gas flows through a heating unit located upstream of one or more exhaust gas treatment units and transports the absorbed heat to the exhaust gas treatment unit(s).

[0003] From DE 10 2018 108 592 A1 and DE 10 2019 134 859 A1, a secondary gas inlet arrangement is known, each with an elongated, essentially cylindrical inlet body extending in the direction of a longitudinal axis. The inlet body has a circumferential wall in which a gas passage opening formation with a plurality of openings is formed.

[0004] The object of the present invention is to provide a secondary gas inlet arrangement with which a uniform distribution of secondary gas introduced into an exhaust system is achieved in the flow cross-section of the exhaust system.

[0005] According to the invention, this problem is solved by a secondary gas inlet arrangement for introducing gas, in particular air, into an exhaust system of an internal combustion engine, comprising a tubular inlet body with a circumferential wall surrounding a gas receiving volume and a longitudinal axis of the body, wherein a gas passage opening formation is provided in the circumferential wall for the exit of gas from the gas receiving volume into a volume surrounding the circumferential wall.

[0006] In one embodiment of the present invention, the secondary gas inlet arrangement is characterized by the fact that - that the circumferential wall is double-walled with an inner wall and an outer wall, wherein a gas passage volume is formed between the inner wall and the outer wall, - that the gas passage opening formation includes inner openings in the inner wall, wherein the gas intake volume is related to the gas passage volume via the inner openings, - that the gas passage opening formation includes outer openings in the outer wall, wherein the gas passage volume is open to the volume surrounding the circumferential wall via the outer openings, and - that at least one inner opening in the circumferential direction around the longitudinal axis of the body and / or in the direction of the longitudinal axis of the body is not completely overlapped by an outer opening, and / or that at least one outer opening in the circumferential direction around the longitudinal axis of the body and / or in the direction of the longitudinal axis of the body is not completely overlapped by an inner opening.

[0007] This arrangement of outer and inner openings relative to each other prevents gas from passing through the circumferential wall in a direction essentially radial to the longitudinal axis of the body, and thus prevents gas from exiting into the volume surrounding the circumferential wall in a direction essentially radial to the longitudinal axis of the body. Because gas flowing into the volume surrounding the circumferential wall also has flow direction components in the circumferential direction around the longitudinal axis of the body, or in the direction of the longitudinal axis itself, this results in greater turbulence of the gas flow and thus a more uniform distribution across the entire cross-section of a flow volume inside an exhaust system. Consequently, a heating unit positioned downstream of the gas inlet, or...This also ensures that an exhaust gas treatment arrangement positioned downstream of the gas inlet, with one or more exhaust gas treatment units, is subjected to a more uniform flow across its cross-sections, thereby avoiding local thermal overload, particularly of such a heating unit, and achieving uniform heating of one or more exhaust gas treatment units across the entire cross-section.

[0008] For particularly efficient turbulence in the vicinity of the inlet body, it is proposed that a plurality of inner openings, preferably each inner opening, are not completely overlapped by an outer opening in the circumferential direction around the longitudinal axis of the body and / or in the direction of the longitudinal axis of the body, and / or that a plurality of outer openings, preferably each outer opening, are not completely overlapped by an inner opening in the circumferential direction around the longitudinal axis of the body and / or in the direction of the longitudinal axis of the body.

[0009] Furthermore, it may be provided that at least one inner opening in the circumferential direction around the longitudinal axis of the body and in the direction of the longitudinal axis of the body is not overlapped by any outer opening, or / and that at least one outer opening in the circumferential direction around the longitudinal axis of the body and in the direction of the longitudinal axis of the body is not overlapped by any inner opening.

[0010] To further enhance this effect, it can be provided that a plurality of inner openings, preferably each inner opening, are not overlapped by any outer opening in the circumferential direction around the longitudinal axis of the body and in the direction of the longitudinal axis of the body, or / and that a plurality of outer openings, preferably each outer opening, are not overlapped by any inner opening in the circumferential direction around the longitudinal axis of the body and in the direction of the longitudinal axis of the body.

[0011] In order to generate the lowest possible flow resistance through the gas passage opening formation on the one hand, and to achieve a gas discharge that is distributed as evenly as possible over the outer surface of the circumferential wall on the other hand, it is proposed that at least one inner opening, preferably several inner openings or each inner opening, has a larger opening cross-section than at least one outer opening, preferably several outer openings or each outer opening.

[0012] To achieve a large cross-sectional area for the gas to be introduced into an exhaust system, at least some of the inner openings, preferably each inner opening, can be designed in an elongated shape.

[0013] The elongated inner openings can be arranged with their longitudinal axis oriented towards the longitudinal axis of the body. Furthermore, the elongated inner openings can be arranged in a plurality of rows, preferably consecutive along the longitudinal axis, with essentially parallel longitudinal axes, or / and in a plurality of rings of consecutive inner openings circumferentially around the longitudinal axis of the body, with essentially parallel longitudinal axes. This ensures a uniform gas outflow pattern across the entire circumference and length of the inlet body.

[0014] To ensure a uniform gas flow with low flow resistance, the number of external openings can be greater than the number of internal openings.

[0015] In order to be able to influence the outflow behavior of the gas by means of different cross-sectional geometries of the various openings, it is proposed that at least some of the outer openings, preferably each outer opening, be designed with a substantially circular opening cross-section.

[0016] Here too, to achieve the densest possible packing of the outer openings, the outer openings, which are formed with a substantially circular cross-section, can be arranged in a plurality of rows of outer openings, preferably following one another substantially in the direction of the longitudinal axis of the body, or / and in a plurality of rings of outer openings following one another circumferentially around the longitudinal axis of the body.

[0017] A design that contributes to a strong flow deflection can be achieved if at least one row of inner openings is provided in the circumferential direction between at least two rows of outer openings that follow each other immediately in the circumferential direction, preferably between all rows of outer openings that follow each other immediately in the circumferential direction.

[0018] In a further embodiment of the present invention, the secondary gas introduction arrangement is characterized in that the gas passage opening formation comprises a plurality of gas passage openings, and that at least one gas passage opening is assigned a flow deflection element for deflecting gas flowing through the gas passage opening in the circumferential direction around the longitudinal axis of the body and / or in the direction of the longitudinal axis of the body.

[0019] It should be noted in this context that this design aspect can be implemented regardless of whether the circumferential wall is single-walled or double-walled. In the case of a double-walled design, such flow deflection elements can preferably be provided on the outer wall.

[0020] For efficient flow deflection, a flow deflection element can be assigned to a plurality of the gas passage openings, preferably to each gas passage opening.

[0021] For a structurally simple design, it is proposed that at least one flow deflection element, preferably each flow deflection element, is formed by deforming the circumferential wall, and / or that at least one flow deflection element, preferably each flow deflection element, is offset radially, preferably radially outwards, with respect to the circumferential wall.

[0022] In a configuration that contributes to strong turbulence of the gas in the area of ​​the gas-receiving volume, it can be provided that at least one flow deflection element, preferably each flow deflection element, connects to the circumferential wall at two flow deflection element end regions, and that a gas passage opening extending between the flow deflection element end regions is formed on both sides of the flow deflection element. With each flow deflection element designed in this way, a portion of the gas will therefore flow through one of the two gas passage openings associated with the flow deflection element and exit into the volume surrounding the inlet body with significantly different flow directions.

[0023] Such flow deflection elements can, for example, be oriented such that, in at least one flow deflection element, preferably each flow deflection element, the flow deflection element end regions are offset from each other in the direction of the longitudinal axis of the body and / or in the circumferential direction around the longitudinal axis of the body.

[0024] In an alternative embodiment of the flow deflection elements, it can be provided that at least one flow deflection element, preferably each flow deflection element, comprises a hood-like formation open circumferentially around the longitudinal axis of the body in one direction and / or in the direction of the longitudinal axis of the body in one direction to provide a gas passage opening. Such hood-like formations make it possible to define a flow direction for the gas in their respective areas, determined by the orientation of the hood-like formation.

[0025] To achieve a dense packing of the flow deflection elements, the flow deflection elements can be arranged in a plurality of rows of flow deflection elements, preferably following one another substantially in the direction of the longitudinal axis of the body, or / and in a plurality of rings of flow deflection elements following one another circumferentially around the longitudinal axis of the body.

[0026] To support strong turbulence in the vicinity of the inlet body, the flow deflection elements of at least one ring of flow deflection elements can be offset circumferentially with respect to the flow deflection elements of at least another ring of flow deflection elements, or / and the flow deflection elements of at least one series of flow deflection elements can be offset in the direction of the longitudinal axis of the body with respect to the flow deflection elements of at least another series of flow deflection elements.

[0027] This effect can be further supported by the fact that, in at least one series of flow deflection elements, the hood-like projections are open in the same direction as the hood-like projections of at least another series of flow deflection elements, or / and that, in at least one series of flow deflection elements, the hood-like projections are open in a first direction and, in at least another series of flow deflection elements, the hood-like projections are open in a second direction that is substantially opposite to the first direction.

[0028] To primarily achieve an outflow of gas through the gas passage opening formation provided in the circumferential wall, it is proposed that the gas intake volume in the direction of the longitudinal axis of the body be limited by a bottom wall adjoining the circumferential wall.

[0029] In particular, if the circumferential wall is double-walled, an essentially exclusive passage of gas through the gas passage volume can be ensured if the gas intake volume is closed off in the direction of the longitudinal axis of the body by the bottom wall.

[0030] The invention further relates to an exhaust gas treatment arrangement comprising at least one exhaust gas treatment unit arranged in a housing and at least one secondary gas inlet arrangement constructed according to the invention and carried on the housing in an area upstream of at least one exhaust gas treatment unit for introducing gas, in particular air, into the exhaust gas treatment arrangement.

[0031] Furthermore, the invention relates to an exhaust system comprising at least one exhaust treatment arrangement constructed in this manner.

[0032] The present invention is described in detail below with reference to the accompanying figures. These show: Fig. 1 a schematic sectional view of an exhaust gas treatment arrangement in an exhaust system of an internal combustion engine; Fig. 2 a perspective view of an inlet body of a secondary gas inlet arrangement of the exhaust system of the Fig. 1; Fig. 3 a partially transparent side view of the inlet body of the Fig. 2; Fig. 4 the inlet body of the Fig. 2 and Fig. 3 in exploded view; Fig. 5 the inlet body of the Fig. 2 and Fig. 3 with partially broken outer wall shown; Fig. 6 a perspective view of an alternative design of a secondary gas inlet arrangement for the exhaust system of the Fig. 1; Fig. 7 a cross-sectional view of the secondary gas inlet arrangement of the Fig. 6, cut along a line VII-VII in Fig. 6; Fig. 8 a basic partial cross-sectional view of an alternative design of an inlet body for a secondary gas inlet arrangement; Fig. 9 a radial view of the in Fig. 8 shown inlet body; Fig. 10 one of the Fig. 9. Corresponding representation of an alternatively designed inlet body; Fig. 11 another of the Fig. 9. Corresponding representation of an alternatively designed inlet body.

[0033] The Fig. Figure 1 shows a schematic representation of an exhaust gas treatment arrangement 10 of an exhaust system, generally designated 12, for an internal combustion engine. The exhaust gas treatment arrangement 10 comprises, within a housing 14, an exhaust gas treatment unit, generally designated 16, which may include, for example, an oxidation catalyst, an SCR catalyst, and / or a particulate filter. Such an exhaust gas treatment unit 16 may comprise a substrate 18, constructed or coated with catalytically active material and having flow channels for the exhaust gas A emitted by an internal combustion engine, which is held in the housing 14, for example, by means of a support mat 20 or the like.

[0034] A heating unit 22 is arranged upstream of the exhaust gas treatment unit 16. This unit can, for example, comprise one or more heating conductors that generate heat when an electrical voltage is applied. The exhaust gas A, flowing towards the heating unit 22 through a conical or funnel-shaped widening section 24 of the housing 14, can absorb heat at the heating unit 22 and release this heat in the area of ​​the substrate 18, thereby heating the substrate or the catalytically active material or maintaining it at a temperature suitable for operation.

[0035] On the housing 14, for example, a secondary gas inlet arrangement, generally designated 26, is mounted upstream of the heating unit 22 or the exhaust gas treatment unit 16 in the area of ​​the funnel-shaped section 24. Gas G, for example air, can be fed into the exhaust system 12 as a secondary gas via the secondary gas inlet arrangement 26. In this way, regardless of whether an internal combustion engine is in operation or not, and therefore whether exhaust gas A is flowing through the exhaust system 12, a gas can be introduced which can absorb heat generated in the area of ​​the heating arrangement 22 and transport it to the area of ​​the exhaust gas treatment unit 16.

[0036] The secondary gas inlet assembly 26, described in detail below with reference to various embodiments, comprises an inlet body 28, which may have a connecting flange 30 at its end region located outside the housing 14. A connecting flange 34 provided on a gas line 32 can be connected to the connecting flange 30, for example by means of a screw connection, in order to connect the secondary gas inlet assembly 26 via the gas line 32 to a source of such secondary gas, for example a blower or a compressor, for supplying air as gas G. The gas G introduced into the secondary gas inlet assembly 26 in this way is introduced via the secondary gas inlet assembly 26 into a volume 35 formed upstream of the heating unit 22.

[0037] The Fig. 2 and Fig. Figure 3 shows a first embodiment of such an exhaust gas treatment unit 26, which has a tubular inlet body 28 elongated in the direction of a longitudinal axis K and a circumferential wall 36. In the Fig. The end region 38 of the inlet body 28 shown above can, for example, be accessed via the inlet. Fig. 1. The connecting flange 30, which is shown in principle and provided at this end area 38, is connected to the gas line 32.

[0038] The circumferential wall 36 of the inlet body 28 is double-walled and comprises an inner wall 40 and an outer wall 42 surrounding the inner wall 40. In a region near the axial end region 38 of the inlet body 28, the outer wall 42 forms a bead-like extension 44, in the region of which the inlet body 28 can be fixed to the housing 14 by a material connection, for example, by welding. Adjoining this bead-like extension region 34, the outer wall 42 is firmly connected to the inner wall 40 in a connecting section 46, preferably by a material connection, for example, by welding. In an end region 48 of the inlet body 28 located inside the housing 14, the inner wall 40 and the outer wall 42 are firmly connected to each other and to a bottom wall 52 in a further connecting section 50 by a material connection, for example, by welding.

[0039] The inner wall 40 surrounds a gas receiving volume 54 for receiving gas G, and a gas passage volume 57 is formed between the inner wall 40 and the outer wall 42. To allow gas G to pass from the gas receiving volume 54 into the volume 35 surrounding the inlet body 28 inside the housing 14, a gas passage opening formation, generally designated 56, is provided. The gas passage opening formation 56 comprises a plurality of inner openings 58 in the inner wall 40 and a plurality of outer openings 60 in the outer wall 42. The gas G entering the gas receiving volume 54 can flow into the gas passage volume 57 via the inner openings 58. The gas G leaving the gas passage volume 57 can flow into the volume 35 surrounding the inlet body 28 inside the housing 14 via the outer openings 60.

[0040] In the Fig. In the embodiment shown in Figures 2-5, the inner openings 58 are elongated and each has a longitudinal axis L that is essentially parallel to the longitudinal axis K of the body. The inner openings 58 are arranged in a plurality of rows 62 of inner openings 58 that follow one another circumferentially around the longitudinal axis K of the body. In each such row 62, the inner openings 58 follow one another in the direction of the longitudinal axis K and are arranged with longitudinal axes L that are parallel to or continue one another. Furthermore, the elongated inner openings 58 are arranged such that several rings 64 of elongated inner openings 58 are formed successively in the direction of the longitudinal axis K.In each such ring 64, the longitudinal axes L of the inner openings 58, which are arranged circumferentially at preferably equal intervals, are essentially parallel to each other.

[0041] The outer openings 60 formed in the outer wall 42 have a substantially circular cross-section. The outer openings 60 are arranged in several circumferentially successive rows 66 of outer openings 60 extending substantially in the direction of the longitudinal axis K of the body, and are arranged in several successive rings 68 of outer openings 60 in the direction of the longitudinal axis K of the body.

[0042] It is in the Fig. Figures 2-5 show that, in both the inner openings 58 and the outer openings 60, the inner and outer openings 58 and 60 arranged in the circumferential direction adjacent to each other in the rows 62 and 66, respectively, are essentially not offset from one another. The same applies to the inner openings 58 and outer openings 60 arranged in different rings 64 and 68, respectively.

[0043] By providing the relatively large inner openings 58 on the inner wall 40 and a larger number of smaller outer openings 60 in the outer wall 42, the flow resistance for the gas G upon entering the gas passage volume 57 is kept low. Furthermore, the large number of outer openings 60 ensures a uniform distribution of gas G into the volume 35 around the circumference and length of the inlet body 28.

[0044] To ensure a uniform distribution of gas G across the entire flow cross-section of the exhaust system 12 or the exhaust gas treatment arrangement 10 during the discharge of gas G into volume 35, the inner openings 58 and the outer openings 60 are arranged relative to each other in such a way that a substantially straight, radially oriented passage of gas G through the gas passage volume 57 is prevented. For this purpose, the inner openings 58 and the outer openings 60 are positioned such that substantially no inner opening 58 completely overlaps one or more of the outer openings 60 in the axial direction and circumferential direction around the longitudinal axis K of the body. In particular, in the illustrated embodiment, the arrangement is such that substantially no inner opening 58 is even partially overlapped by an outer opening 60 in the axial direction and circumferential direction around the longitudinal axis K of the body.The rows 62 of the inner openings 58 are positioned such that they are offset in the circumferential direction with respect to the rows 66 of outer openings 60 such that each row 62 of the inner openings 58 is positioned in the circumferential direction between two rows 66 of the outer openings 60.

[0045] When gas G passes through the gas passage volume 56, not only is a flow deflection forced radially outwards with respect to the longitudinal axis K of the body, but also a deflection in the circumferential direction or in the axial direction, so that the gas G exiting from the inlet body 28 into the surrounding volume 35 will contribute to a comparatively strong turbulence in the vicinity of the inlet body 28 or in the volume 35, which in turn ensures that the gas G will distribute itself evenly in the volume 35 and therefore, despite the offset and inclined arrangement of the secondary gas inlet arrangement 26 with respect to a longitudinal center axis M of the exhaust gas treatment arrangement 10, contributes to an almost uniform flow towards the heating unit 22 and the exhaust gas treatment unit 16.Since the bottom wall 52 completely closes off the gas intake volume 64 in the direction of the longitudinal axis K of the body, it is further ensured that all the gas G introduced into the gas intake volume 54 is released via the gas passage opening formation 56 into the volume 35 surrounding the inlet body 28, generating turbulence.

[0046] It should be noted that variations are possible, particularly with regard to the arrangement of the inner openings 58 and the outer openings 60, as well as their shape, without deviating from the principle of generating turbulence through flow deflection. For example, the different rows 62 of inner openings 58 could differ from the one shown in Fig. The orientation shown in Figure 2, precisely aligned with the longitudinal axis K of the body, exhibits a helical course. The inner openings 58 and outer openings 60 arranged in the various rings 64 and 68 of inner openings 58 and outer openings 60, respectively, could be offset from one another in the direction of the longitudinal axis K, so that such rings 64, 68 could have a course angled with respect to the longitudinal axis K. Furthermore, openings of different dimensions or shapes could be provided in the various rows 62 or rings 64 of inner openings 58, which could likewise be the case for the various rows 66 and rings 68 of outer openings 60.

[0047] An alternative embodiment of a secondary gas inlet arrangement 26 is described in the Fig. 6 and Fig. Figure 7 shows that in this secondary gas inlet arrangement 26, the inlet body 28 has a single-walled circumferential wall 36. The circumferential wall 36 provides the bead-like expanded area 44, which forms the area of ​​the largest radial dimension of the inlet body 28 and in which the inlet body 28 can be fixed to the housing 14. Fig. Figure 6 shows the connecting flange 30 fixed to the inlet body 28. In its area to be positioned inside the housing 14, the inlet body 28 has a plurality of flow deflection elements 70. Each of the flow deflection elements 70 is formed by creating two slots in the circumferential wall 36 that are parallel to each other and extend essentially in the direction of the longitudinal axis K of the body, and by deforming the length between these slots radially outwards. In this way, each flow deflection element 70, which is essentially formed integrally with the circumferential wall 36, is connected to the circumferential wall 36 at its two flow deflection element end regions 72, 74.By deforming radially outwards, elongated gas passage openings 76 of the gas passage opening formation 56 are created on both sides of each flow deflection element 70 in the direction of the flow deflection element 70 and thus also in the direction of the longitudinal axis K of the body.

[0048] In Fig. Figure 6 shows that the flow deflection elements 70 are arranged in successive rings 78 in the direction of the longitudinal axis K of the body. In the illustrated embodiment, the flow deflection elements 70 assigned to the different rings 78 are arranged offset from one another in the circumferential direction, so that each flow deflection element 70 from one of the rings 78 is positioned circumferentially between two flow deflection elements 70 of the other ring 78. In this way, a very dense packing of the flow deflection elements 70 and, consequently, of the gas passage openings 76 can be achieved both in the direction of the longitudinal axis K and in the circumferential direction, without impairing the stability of the circumferential wall 36.

[0049] By providing the flow deflection elements 70, this embodiment of a secondary gas inlet arrangement 26 also ensures that a precisely radial exit of the gas G from the gas receiving volume 54 is not possible. Rather, the gas exiting the gas receiving volume 54 is deflected circumferentially in both directions at each of the flow deflection elements 70, so that a comparatively strong turbulence of the gas G in the vicinity of the inlet body 28 is generated.

[0050] In Fig. Figure 6 shows that openings 80 can be formed in the bottom wall 52, which limits the gas intake volume 54 in the direction of the longitudinal axis K of the body, allowing a portion of the gas G to escape in the direction of the longitudinal axis K, which can contribute to a more uniform flow of gas G to the heating unit 22 or the exhaust gas treatment unit 16, particularly in the case of a single-walled design of the circumferential wall 36.

[0051] Also with reference to the in the Fig. 6 and Fig. Regarding the embodiment shown in Figure 7, it should be noted that other structures and positions of the flow deflection elements 70 are of course possible. For example, the generally elongated, strip-like flow deflection elements 70 could have an orientation that deviates from their orientation essentially along the longitudinal axis K of the body and, for instance, define a helical structure along the circumferential wall 36 or extend circumferentially. The flow deflection elements 70 could also be shorter, so that, for example, their length between the two end regions 72, 74 of the flow deflection elements could approximately correspond to their length perpendicular to this. This allows for a larger number of rings 78 along the longitudinal axis K of the body.

[0052] Another embodiment of an inlet body 28 constructed with a single-walled circumferential wall 36 is described in the Fig. 8 and Fig. Figure 9 is shown in principle. In this embodiment, the flow deflection elements 70 are designed as hood-like projections 77, which can be created, for example, by producing a slot in the circumferential wall 36 and by shaping the circumferential wall 36 radially outwards in an area adjacent to such a slot. The hood-shaped flow deflection elements 70 can, for example, have the form of a spherical cap section and each provide a gas passage opening 76 from which the gas G introduced into the gas receiving volume 54 can flow out approximately in the circumferential direction.

[0053] As the Fig. As illustrated in Figure 9, the hood-shaped flow deflection elements 70 can be arranged in rows 82 of deflection elements 70 extending in the direction of the longitudinal axis K and positioned at intervals around the longitudinal axis K, or in rings 78 of flow deflection elements 70 surrounding the longitudinal axis K. As shown in Figure 9, the two upper ones in Fig. The 9 depicted rows 82 of flow deflection elements 70 illustrate that the flow deflection elements 70 of immediately adjacent rows are not offset from each other in the direction of the longitudinal axis K of the body, or, as the two lower ones in Fig. The rows 82 shown in Figure 9 illustrate that the flow deflection elements 70 arranged in immediately adjacent rows 82 are offset from one another in the direction of the longitudinal axis K of the body. A correspondingly aligned or circumferentially offset positioning of the flow deflection elements 70 can also be provided for rings 78 of flow deflection elements 70 that are immediately adjacent to one another in the direction of the longitudinal axis K of the body.

[0054] Furthermore, the Fig. 9, that the various rows 82 of flow deflection elements 70 assigned to the flow deflection elements 70 can be oriented such that the gas G flowing out of them in the circumferential direction exits the flow deflection elements 70 in opposite directions to each other, as is the case with the two upper ones in Fig. The 7 rows shown are 82. The two lower ones in Fig. The 9 depicted rows 82 show that in adjacent rows 82, the flow deflection elements 70 can be oriented such that the gas G flowing out of them, essentially in the circumferential direction, is released essentially in the same direction. It is also possible that different orientations are provided in a row 82 or a ring 78 of such flow deflection elements 70, so that the gas G exiting from some of the flow deflection elements 70 is released in one circumferential direction, while from the remaining portion of the flow deflection elements 70, the gas G exiting from them is released in the other circumferential direction. Furthermore, some or all of the flow deflection elements 70, designed as hood-like projections 77, could be arranged or oriented such that the gas exiting from them exits essentially in the direction of the longitudinal axis K of the body or at an angle to it.

[0055] Examples of such flow deflection elements 70 with a hood-like structure are in the Fig. 10 and Fig. 11 shown. Fig. Figure 10 shows a plurality of rows 82 hood-shaped flow deflection elements 70 extending in the direction of the longitudinal axis K of the body, wherein all flow deflection elements 70 have the same orientation and thus the gas is released circumferentially in the same direction from all flow deflection elements 70. Furthermore, in Fig. 10 to recognize that the flow deflection elements 70 arranged in adjacent rows 82 are offset from each other, so that the flow deflection elements 70 assigned to the different rings 78 alternately overlap each other in the direction of the longitudinal axis K of the body.

[0056] At the in Fig.In the illustrated embodiment 11, in each pair of immediately adjacent rows 82 of flow deflection elements 70, the flow deflection elements 70 are oriented such that the gas exiting them is released circumferentially in opposite directions. Furthermore, it can be seen that several such paired rows 82 can be provided, with immediately adjacent pairs of such rows 82 being offset from each other in the direction of the longitudinal axis K of the body.

Claims

[1] Secondary gas inlet arrangement for introducing gas into an exhaust system of an internal combustion engine, comprising a tubular inlet body (28) with a circumferential wall (36) surrounding a gas receiving volume (54) and a longitudinal axis (K), wherein a gas passage opening formation (56) is provided in the circumferential wall (36) for the exit of gas from the gas receiving volume (54) into a volume (35) surrounding the circumferential wall (36), characterized by , - that the circumferential wall (36) is double-walled with an inner wall (40) and an outer wall (42), wherein a gas passage volume (57) is formed between the inner wall (40) and the outer wall (42), - that the gas passage opening formation (56) comprises inner openings (58) in the inner wall (40), wherein the gas intake volume (54) is connected to the gas passage volume (57) via the inner openings (58), - that the gas passage opening formation (56) comprises outer openings (60) in the outer wall (42), wherein the gas passage volume (57) is open to the volume (35) surrounding the circumferential wall (36) via the outer openings (60), and - that at least one inner opening (58) is not completely overlapped by an outer opening (60) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K), or / and that at least one outer opening (60) is not completely overlapped by an inner opening (58) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K). [2] Secondary gas inlet arrangement according to claim 1, characterized by, that a plurality of inner openings (58) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K) is not completely overlapped by an outer opening (60), or / and that a plurality of outer openings (60) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K) is not completely overlapped by an inner opening (58). [3] Secondary gas inlet arrangement according to claim 2, characterized by , that each inner opening (58) is not completely overlapped by an outer opening (60) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K), or / and that each outer opening (60) is not completely overlapped by an inner opening (58) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K). [4] Secondary gas inlet arrangement according to claim 1, 2 or 3, characterized by, that at least one inner opening (58) is not overlapped by any outer opening (60) in the circumferential direction around the longitudinal axis (K) of the body and in the direction of the longitudinal axis (K), or / and that at least one outer opening (60) is not overlapped by any inner opening (58) in the circumferential direction around the longitudinal axis (K) of the body and in the direction of the longitudinal axis (K). [5] Secondary gas inlet arrangement according to claim 4, characterized by , that a plurality of inner openings (58) in the circumferential direction around the longitudinal axis (K) of the body and in the direction of the longitudinal axis (K) are not overlapped by any outer opening (60), or / and that a plurality of outer openings (60) in the circumferential direction around the longitudinal axis (K) of the body and in the direction of the longitudinal axis (K) are not overlapped by any inner opening (58). [6] Secondary gas inlet arrangement according to claim 5, characterized by, that each inner opening (58) is not overlapped by any outer opening (60) in the circumferential direction around the longitudinal axis (K) of the body and in the direction of the longitudinal axis (K), or / and each outer opening (60) is not overlapped by any inner opening (58) in the circumferential direction around the longitudinal axis (K) of the body and in the direction of the longitudinal axis (K). [7] Secondary gas inlet arrangement according to one of claims 1-6, characterized by , that at least one inner opening (58) has a larger opening cross-section than at least one outer opening (60) and / or that at least part of the inner openings (58) are shaped like elongated holes. [8] Secondary gas inlet arrangement according to claim 7, characterized by , that several internal openings (58) or each internal opening (58) has a larger opening cross-section than several external openings (60) or each external opening (60), and / or that each internal opening (58) is shaped like an elongated hole. [9] Secondary gas inlet arrangement according to claim 7 or 8, characterized by , that the elongated inner openings (58) are arranged with an opening longitudinal axis (L) oriented in the direction of the body longitudinal axis (K), or / and that the elongated inner openings (58) are arranged in a plurality of rows (62) of successive inner openings (58) with opening longitudinal axes (L) parallel to each other, or / and in a plurality of rings (64) of inner openings (58) arranged circumferentially around the body longitudinal axis (K) with opening longitudinal axes (L) parallel to each other. [10] Secondary gas inlet arrangement according to claim 9, characterized by , that in the rows (62) of successive inner openings (58) the inner openings (58) follow one another in the direction of the longitudinal axis (L) of the opening. [11] Secondary gas inlet arrangement according to one of claims 1-10, characterized by, that the number of outer openings (60) is greater than the number of inner openings (58), or / and that at least some of the outer openings (60) have a circular cross-section. [12] Secondary gas inlet arrangement according to claim 11, characterized by , that each outer opening (60) is designed with a circular opening cross-section. [13] Secondary gas inlet arrangement according to claim 11 or 12, characterized by , that the outer openings (60) having a circular cross-section are arranged in a plurality of rows (66) of successive outer openings (60) or / and in a plurality of rings (68) of outer openings (60) arranged in a circumferential direction around the longitudinal axis (K) of the body. [14] Secondary gas inlet arrangement according to claim 13, characterized by, that in the rows (66) of successive outer openings (60) the outer openings (60) follow one another in the direction of the longitudinal axis (K) of the body. [15] Secondary gas inlet arrangement according to claim 9 and claim 13 or 14, characterized by , that in the circumferential direction at least one row (62) of inner openings (58) is provided between at least two circumferentially consecutive rows (66) of outer openings (60). [16] Secondary gas inlet arrangement according to claim 15, characterized by , that in the circumferential direction at least one row (62) of inner openings (58) is provided between all the circumferentially consecutive rows (66) of outer openings (60). [17] Secondary gas inlet arrangement according to any one of claims 1-16 or the preamble of claim 1, characterized by, that the gas passage opening formation (56) comprises a plurality of gas passage openings (76), and that at least one gas passage opening (76) is associated with a flow deflecting element (70) for deflecting gas (G) flowing through the gas passage opening (76) in the circumferential direction around the longitudinal axis (K) of the body or / and in the direction of the longitudinal axis (K). [18] Secondary gas inlet arrangement according to claim 17, characterized by , that a majority of the gas passage openings (76) are each assigned a flow deflection element (70). [19] Secondary gas inlet arrangement according to claim 18, characterized by , that each gas passage opening (76) is assigned a flow deflection element (70). [20] Secondary gas inlet arrangement according to claim 17, 18 or 19, characterized by, that at least one flow deflection element (70) is formed by reshaping the circumferential wall (36), or / and that at least one flow deflection element (70) is radially offset with respect to the circumferential wall (36). [21] Secondary gas inlet arrangement according to claim 20, characterized by , that each flow deflection element (70) is formed by reshaping the circumferential wall (36), or / and that each flow deflection element (70) is radially offset with respect to the circumferential wall (36), or / and that at least one flow deflection element (70) is radially offset outwards with respect to the circumferential wall (36). [22] Secondary gas inlet arrangement according to claim 21, characterized by, that at least one flow deflection element (70) connects to the circumferential wall (36) in two flow deflection element end regions (72, 74), and that on both sides of the flow deflection element (70) a gas passage opening (76) extending between the flow deflection element end regions (72, 74) is formed. [23] Secondary gas inlet arrangement according to claim 22, characterized by , that each flow deflection element (70) connects to the circumferential wall (36) in two flow deflection element end regions (72, 74). [24] Secondary gas inlet arrangement according to claim 22 or 23, characterized by , that in at least one flow deflection element (70) the flow deflection element end regions (72, 74) are offset from each other in the direction of the longitudinal axis of the body (K) and / or in the circumferential direction around the longitudinal axis of the body (K). [25] Secondary gas inlet arrangement according to claim 24, characterized by, that in each flow deflection element (70) the flow deflection element end regions (72, 74) are offset from each other in the direction of the longitudinal axis of the body (K) and / or in the circumferential direction around the longitudinal axis of the body (K). [26] Secondary gas inlet arrangement according to one of claims 17-25, characterized by , that at least one flow deflection element (70) comprises a hood-like formation (77) open in a circumferential direction around the longitudinal axis (K) of the body and / or in a direction around the longitudinal axis (K) of the body to provide a gas passage opening (76). [27] Secondary gas inlet arrangement according to claim 26, characterized by , that each flow deflection element (70) comprises a hood-like formation (77) open in a circumferential direction around the longitudinal axis (K) of the body and / or in a direction around the longitudinal axis (K) of the body to provide a gas passage opening (76). [28] Secondary gas inlet arrangement according to one of claims 17-27, characterized by , that the flow deflection elements (70) are arranged in a plurality of rows (82) of successive flow deflection elements (70) or / and in a plurality of rings (78) of flow deflection elements (70) arranged in a circumferential direction around the longitudinal axis (K) of the body. [29] Secondary gas inlet arrangement according to claim 28, characterized by , that in the rows (82) of flow deflection elements (70) following one another in the direction of the longitudinal axis (K) of the body, the flow deflection elements (70) follow one another in the direction of the longitudinal axis (K). [30] Secondary gas inlet arrangement according to claim 28 or 29, characterized by, that the flow deflection elements (70) of at least one ring (78) of flow deflection elements (70) are offset in the circumferential direction with respect to the flow deflection elements (70) of at least one other ring (78) of flow deflection elements (70), or / and that the flow deflection elements (70) of at least one row (82) of flow deflection elements (70) are offset in the direction of the longitudinal axis of the body with respect to the flow deflection elements (70) of at least one other row (82) of flow deflection elements (70). [31] Secondary gas inlet arrangement according to claim 26 and one of claims 27-30, characterized by, that in at least one row (82) of flow deflection elements (70) the hood-like projections (77) are open in the same direction as the hood-like projections of at least one other row (82) of flow deflection elements (70), or / and that in at least one row (82) of flow deflection elements (70) the hood-like projections (77) are open in a first direction and in at least one other row (82) of flow deflection elements (70) the hood-like projections (77) are open in a second direction opposite to the first direction. [32] Secondary gas inlet arrangement according to one of claims 1-31, characterized by , that the gas absorption volume (54) in the direction of the longitudinal axis (K) of the body is limited by a bottom wall (52) adjoining the circumferential wall (36). [33] Secondary gas inlet arrangement according to claim 1 or any one of claims 2-32, insofar as it relates back to claim 1, characterized by, that the gas absorption volume (54) is closed off in the direction of the longitudinal axis of the body (K) by the bottom wall (52). [34] Exhaust gas treatment arrangement comprising at least one exhaust gas treatment unit (16) arranged in a housing (14) and at least one secondary gas inlet arrangement (26) carried on the housing (14) in an area upstream of at least one exhaust gas treatment unit (16) according to one of claims 1-33 for inleting gas into the exhaust gas treatment arrangement (10). [35] Exhaust system comprising at least one exhaust treatment arrangement (10) according to claim 34.

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