Exhaust treatment device

Abstract

The invention relates to an exhaust treatment device for an exhaust system of an internal combustion engine, comprising a housing (14) which extends elongated in the direction of a housing longitudinal axis (L) and at least one exhaust treatment unit (20, 22) with a housing shell (24) arranged in the housing (14), wherein at least one bearing / sealing unit (34) is arranged in a radial gap (36) formed between the housing shell (24) and the housing (14), the bearing / sealing unit having at least two radially following one another, nested and each interrupted in the circumferential direction in a circumferential interruption region (46, 48), wherein the circumferential interruption region (46) of at least one of the bearing / sealing rings (42, 44) is offset in the circumferential direction relative to the circumferential interruption region (48) of the other of the bearing / sealing rings (42, 44).

Description

TECHNICAL FIELD

[0001] The invention relates to an exhaust-gas treatment device for an exhaust system of an internal combustion engine. BACKGROUND

[0002] In exhaust-gas treatment devices for exhaust systems of internal combustion engines it is known for one or more exhaust-gas treatment units, for example catalysts or particle filters, to be inserted as prefabricated structures into a housing of such an exhaust-gas treatment unit which is elongated in the direction of the longitudinal axis of the housing in order to guide the entire exhaust-gas flow substantially through the exhaust-gas treatment unit. In order to be held in the housing with defined play and in order to prevent a leakage flow, at least one support / seal unit which is annularly encompassing the housing shell, for example constructed with a wire mesh, is provided in the radial gap formed between the housing shell and the housing. SUMMARY

[0003] It is an object of the invention to provide an exhaust-gas treatment device for an exhaust system of an internal combustion engine in which the formation of a leakage flow is avoided by simple structural measures.

[0004] According to the invention, this object is achieved by an exhaust-gas treatment device for an exhaust system of an internal combustion engine comprising a housing which is elongated in the direction of the longitudinal axis of the housing and at least one exhaust-gas treatment unit with a housing shell arranged in the housing, wherein at least one support / seal unit is arranged in the radial gap formed between the housing shell and the housing, the support / seal unit having at least two support / seal rings which follow one another radially, are nested with one another and are interrupted in the circumferential direction in a circumferential interruption region each, wherein the circumferential interruption region of at least one of the support / seal rings is offset in the circumferential direction relative to the circumferential interruption region of the other support / seal ring.

[0005] By providing a plurality of support / seal rings which are interrupted in the circumferential direction, on the one hand a very good adaptability of the support / seal unit to the two components which are supported relative to one another and sealed relative to one another in order to avoid a leakage flow is achieved. In particular, unavoidable dimensional tolerances do not adversely affect the functionality of the support and the sealing. Since the circumferential interruptions of the different support / seal rings of the support / seal unit which enable the adaptability are offset from one another in the circumferential direction, a leakage flow can also not substantially form in these circumferential regions.

[0006] In order to achieve an optimum interaction of the support / seal rings of the support / seal unit for a very good sealing effect, it is proposed that at least two support / seal rings, preferably all support / seal rings, of the at least one support / seal unit are constructed identically to one another in structure.

[0007] A very good sealing effect can be supported in that in at least two support / sealing rings of the at least one support / sealing unit the circumferential interruption regions are offset from one another in the circumferential direction by approximately 180°.

[0008] In order to also take into account mechanical stability design in view of the thermal loads occurring when the exhaust system is in operation, at least two support / sealing rings, preferably all support / sealing rings, of the at least one support / sealing unit can be composed of a metallic material.

[0009] For this purpose, for example, at least two support / sealing rings, preferably all support / sealing rings, of the at least one support / sealing unit can be configured as metallic formed parts, i.e. for example as so-called metal flanged seals.

[0010] In order to be able to nest the radially stepped (staggered) support / sealing rings of the support / sealing unit well into one another in order to achieve an effective sealing effect and here to realize a substantially gas-tight closure in the mutually bridging circumferential interruption regions, it is proposed that the support / sealing rings of the at least one support / sealing unit have a substantially U-shaped or substantially V-shaped or substantially W-shaped or substantially M-shaped or substantially wave-shaped cross-sectional profile.

[0011] For an effective sealing effect, the circumferential interruption region can extend over less than 5%, preferably less than 2%, of the total circumference of the support / sealing ring in at least one support / sealing ring, preferably in each support / sealing ring, of the at least one support / sealing unit. For example, a configuration can be realized in which such a support / sealing ring extends over a circumferential region of 355° to 359°.

[0012] At least one exhaust treatment element, preferably a catalyst assembly and / or a particulate filter assembly, can be arranged in the housing of the at least one exhaust treatment unit.

[0013] The invention also relates to an exhaust system for an internal combustion engine, comprising at least one exhaust treatment device according to the invention. BRIEF DESCRIPTION OF DRAWINGS

[0014] The invention is described below with reference to the drawings. In the drawings,

[0015] Figure 1 A sectional view of an exhaust treatment device in an exhaust system for an internal combustion engine is shown, with an exhaust treatment unit embedded in a housing;

[0016] Figure 2 An enlarged detail II of Figure 1 is shown;

[0017] Figure 3 A schematic view of a support / sealing unit used in the exhaust treatment device of Figure 1 is shown, which, in the region of thethe observation direction III-III in Figure 6

[0018] Figure 4 shown side by side Figure 3 two support / seal rings of the sealing unit of

[0019] Figure 5 shown side by side Figure 3 two support / seal rings of the support / seal unit of

[0020] Figure 6 showing the arrangement of two support / seal rings nested into each other when viewed in the observation direction VI in Figure 3 Figure 5

[0021] Figure 7 showing an alternative cross-sectional geometry for a support / seal ring. DETAILED DESCRIPTION

[0022] In Figure 1 , an exhaust treatment device, generally designated 10, for an exhaust system 12 of an internal combustion engine is shown, for example, in a vehicle. The exhaust treatment device 10 comprises a tubular and, for example, sheet metal formed housing 14 which is elongated in the direction of a housing longitudinal axis L and has an as far as possible substantially cylindrical structure. At an upstream end region 16, a deflection housing, generally designated 18, is connected to the housing 14. The deflection housing deflects an exhaust flow A flowing through the exhaust system 12 towards the upstream end region 16 of the housing 14.

[0023] In the shown embodiment, two exhaust treatment units 20, 22 are arranged axially following in the housing 14. Each of these exhaust treatment units 20, 22 comprises, as explained in more detail by way of the exhaust treatment unit 22, a substantially tubular casing 24, for example made of sheet metal, in which two exhaust treatment elements 26, 28 are arranged following each other in the exhaust flow direction or housing longitudinal axis L. As such exhaust treatment elements 26, 28, catalytic converters, for example oxidation catalytic converters or SCR catalytic converters, particulate filters, etc. can be used. Of course, more than two or even only a single exhaust treatment element can be provided inside such a casing 24 and can be held therein, for example, by a fiber mat or the like surrounding the exhaust treatment element.

[0024] ​​In the assembly of the exhaust treatment device 10, the exhaust treatment units 20, 22 to be received in the housing 14 are inserted into the housing 14 in the direction of the housing longitudinal axis L from the downstream end of the housing 14. Here, the exhaust treatment unit 22 further positioned upstream can be moved up to the point at which it abuts against the radially inwardly curved edge region 30 of the housing 14, thereby defining a defined axial positioning. In order to also achieve a defined radial positioning of the exhaust treatment units 20, 22, in particular of the exhaust treatment unit 22 further positioned upstream, a bearing / sealing unit 32, 34 is provided in at least one axial region, preferably in both axial end regions of the exhaust treatment unit 22, which on the one hand ensures that the exhaust treatment unit 22 is supported in a defined manner in the radial direction relative to the housing 14 and on the other hand ensures that the exhaust gas A flowing into the upstream end region 16 of the housing 14 substantially completely enters the interior of the housing 24 and thus can be subjected to a catalytic reaction, for example, in the exhaust treatment elements, while substantially no exhaust gas flows through the annular intermediate space 36 formed between the housing 24 and the housing 14.

[0025] The design of such a bearing / sealing unit is described below with reference to the bearing / sealing unit 34 further positioned upstream in the exhaust treatment unit 22. Of course, the bearing / sealing unit 32 at the region further positioned downstream of the exhaust treatment unit 22 can also be configured in the manner described below. The bearing / sealing unit assigned to the further exhaust treatment unit 20 arranged in the housing 14, if any, can also be configured in the manner described below.

[0026] The sealing unit 34 arranged between the two, for example slightly radially inwardly shaped but at the same time substantially cylindrical, end sections 38, 40 of the housing 14 or the housing 24, which in principle surrounds the housing longitudinal axis L or the housing 24 annularly or over the entire circumference, comprises two bearing / sealing rings 42, 44 which are arranged radially following one another relative to the housing longitudinal axis L and are nested in one another. The two bearing / sealing rings 42, 44 are substantially identically configured to one another and are configured in the embodiment shown as having a substantially U-shaped cross-sectional geometry. The bearing / sealing rings 42, 44 are preferably configured as metal formed parts made of a relatively thin and thus flexible sheet metal, for example having a thickness of approximately 0.2 mm, and can be configured in the form of so-called metal flanged seals.

[0027] As can be gathered from Figure 5 and Figure 6 , the two bearing / sealing rings 42, 44 are not configured as rings which are closed in the circumferential direction, i.e. which extend over a circumferential range of 360°. Each of the two bearing / sealing rings 42, 44 has a circumferential interruption region 46, 48 in the circumferential region and is thus configured as an open ring. For example, each bearing / sealing ring can extend over a circumferential range of 355° to 359°.

[0028] In the assembled configuration of the support / seal unit 34 comprising the two support / seal rings 42, 44, the support / seal rings 42, 44 are positioned or rotated relative to each other such that their circumferential interruption regions 46, 48 are offset from each other in the circumferential direction. Preferably, the arrangement is such that the circumferential interruption region 46 of the support / seal ring 42, which is further positioned radially inward, is offset by approximately 180° relative to the circumferential interruption region 48 of the support / seal ring 44, which is further positioned radially outward, so that the two circumferential interruption regions 46, 48 are essentially diametrically opposite relative to the housing longitudinal axis L.

[0029] In the combined state of the two support / seal rings 42, 44, they are nested in each other such that, in principle, the two U-shaped legs 50, 52 of the support / seal ring 44, which is further positioned radially outward, lie against the outside of the two U-shaped legs 54, 56 of the support / seal ring 42, which is further positioned radially inward. The tabs 58, 60, which connect the two U-shaped legs 50, 52 or 54, 56 to each other, of the two support / seal rings 44, 42 can in principle have a small radial distance relative to each other before the exhaust treatment device 10 is assembled.

[0030] When assembling and in particular when integrating such a support / seal unit 34 into the exhaust treatment device 10, the support / seal unit 34 comprising the two support / seal rings 42, 44, which are arranged nested in each other, is pushed onto the end section 40 of the housing 24 before the exhaust treatment device unit 22 is inserted, so that the free ends of the U-shaped legs 54, 56 of the support / seal ring 42, which is further positioned radially inward, rest on the outside of the housing 24. Subsequently, the exhaust treatment unit 22, which is equipped with the support / seal unit 34, is inserted into the housing 14. At the latest when the support / seal unit 34 reaches the transition to the radially inwardly offset end section 38 of the housing 14, the support / seal ring 44, which is further positioned radially outward, lies with its tabs 58 against the inner surface of the housing 14 and is pressed radially inward onto the support / seal ring 42, which is further positioned radially inward. Due to the support / seal rings 42, 44, which are constructed with a relatively thin material and are therefore flexible, they can be slightly deformed when loaded in this way, so that on the one hand the two support / seal rings 42, 44 are pressed radially against each other and on the other hand they are pressed against the housing 14 or the housing 24 and thus essentially over the entire circumference provide a defined radial holding effect for the exhaust treatment unit 22 on the one hand and also produce an essentially gas-tight closure of the gap 36 on the other hand.

[0031] Due to the fact that the two circumferential interruption regions 46, 48 are offset from one another and thus bridged by the support / seal rings 42, 44 in these circumferential interruption regions 46, 48, a substantially gas-tight closure of the intermediate space 36 is also ensured in these circumferential interruption regions 46, 48. This also contributes in particular to the fact that the two support / seal rings 42, 44 are not completely rigid, but are deformed by the radial loading exerted by means of the housing 14 and the cover 24 and thus can adapt to their outer or inner circumferential contour. In particular in this way, shape tolerances or dimensional tolerances of the housing 14 or the exhaust treatment unit 22 and changes in the radial distance between these components resulting from thermal expansion of these components can also be compensated.

[0032] By using such a support / seal unit 34 with two support / seal rings 42, 44 made of a relatively thin-walled and thus slightly deformed metal material, on the one hand it is ensured that a tight closure, which particularly excludes leakage flows in the upstream end region of the housing 14, is achieved due to the shape adaptation of the support / seal unit 34 when inserting the exhaust treatment unit 22 into the housing 14 at a relatively low resistance. Since the support / seal rings 42, 44, which are identically constructed with respect to one another, can be used for the support / seal unit 34, it can be produced with a minimum number of different or differently designed structural components and is particularly also shape-stable under the influence of temperature and is able to adapt to shape changes of the components to be sealed with respect to one another triggered thereby in the event of temperature changes.

[0033] Since the occurrence of leakage flows is practically excluded by using such a support / seal unit 34, particularly in the upstream end region of the exhaust treatment unit 22 or the housing 14 receiving the exhaust treatment unit, and thus the exhaust gas A to be freed of harmful substances flows substantially completely through the interior of the cover 24 and thus through the exhaust treatment elements 26, 28 arranged therein, it is possible, for example, to select a different, as far as possible more cost-effective or more easily realizable structure for the support / seal device 32, which necessarily does not have to ensure the same degree of tightness. If a further exhaust treatment unit 20 follows downstream of the exhaust treatment unit 22, it can also be supported and sealed with respect to the housing 14, for example at least in its upstream end region, with a support / seal unit which corresponds to the support / seal unit 34 in its structure.

[0034] It should be noted that in the design of such bearing / sealing units 34 various variations are possible. Thus, for example, more than two bearing / sealing rings can also be arranged nested into one another, which can be particularly advantageous if the radially intermediate space 36 formed between the housing 24 and the casing 14 has a relatively large radial extension. In the case of the use of more than two bearing / sealing rings, it can be provided in order to achieve an effective sealing effect that the circumferential distance of the circumferentially interrupted regions of the bearing / sealing rings corresponds to an angular distance which corresponds to a division of 360° by (divided by) the number of bearing / sealing rings used. If there are three bearing / sealing rings in one bearing / sealing unit, this circumferential distance of the circumferentially interrupted regions can be in the range of 120°. In the case of four bearing / sealing rings in one bearing / sealing unit, this circumferential distance of the circumferentially interrupted regions can be in the range of 90°.

[0035] Furthermore, the bearing / sealing rings of such bearing / sealing units can have a cross-sectional geometry which differs from the U-shaped cross-sectional geometry visible in Figures 2 to 4 This is shown, for example, in Figure 7 The bearing / sealing rings used in such bearing / sealing units 34 can thus be configured, for example, with a D-shaped cross-sectional geometry, wherein the free ends of the two W legs located on the outside and the connecting region located therebetween can be oriented radially outwards, while the two Figure 7 a) connecting regions visible below can be oriented radially inwards. As shown in Figure 7 b), an M-shaped cross-sectional geometry of the bearing / sealing rings is also possible, which essentially reverses the arrangement of the support regions with respect to the W-shaped form in relation to the provision of the casing 14 and the housing 24. Furthermore, a V-shaped form in principle is possible, as shown in Figure 7 c), wherein the two free ends of the V legs can also be further oriented radially outwards or radially inwards here. Finally, Figure 7 d) shows a generally undulating cross-sectional geometry of such bearing / sealing rings, wherein the wave crests follow one another in the axial direction, which alternately support radially outwards and radially inwards. Here, the number of wave crests supporting radially outwards or radially inwards can be the same, or for example the wave crests supporting radially outwards can be more or less than the wave crests supporting radially inwards.

Claims

1. An exhaust treatment device for an exhaust system of an internal combustion engine, the exhaust treatment device comprising a housing (14) extending elongated in the longitudinal axis (L) direction of the housing and at least one exhaust treatment unit (20, 22) having a cover (24) disposed in the housing (14), wherein, At least one support / sealing unit (34) is arranged in a radial intermediate space (36) formed between the cover (24) and the housing (14), the support / sealing unit having at least two radially following and nested support / sealing rings (42, 44), each support / sealing ring (42, 44) being interrupted in a circumferential interruption region (46, 48), in which the circumferential ends of each support / sealing ring (42, 44) being circumferentially opposite each other have a circumferential distance from each other, wherein at least two support / sealing rings (42, 44) of the at least one support / sealing unit (34) are configured as metal forming parts, wherein the circumferential interruption region (46) of at least one support / sealing ring (42, 44) is offset in the circumferential direction from the circumferential interruption region (48) of the other support / sealing ring (42, 44).

2. The exhaust gas treatment device according to claim 1, characterized in that, The at least two support / sealing rings (42, 44) of the at least one support / sealing unit (34) are constructed identically to each other.

3. The exhaust gas treatment device according to claim 1 or 2, characterized in that, In at least two support / sealing rings (42, 44) of the at least one support / sealing unit (34), the circumferential interruption regions (46, 48) are offset from each other by about 180° in the circumferential direction.

4. The exhaust gas treatment device according to claim 1 or 2, characterized in that, All support / sealing rings (42, 44) of the at least one support / sealing unit (34) are constructed as metal-formed components.

5. The exhaust gas treatment device according to claim 1 or 2, characterized in that, The support / sealing ring (42, 44) of the at least one support / sealing unit has a U-shaped, V-shaped, W-shaped, M-shaped or wavy cross-sectional profile.

6. The exhaust gas treatment device according to claim 1 or 2, characterized in that, In at least one support / sealing ring (42, 44) of the at least one support / sealing unit (34), the circumferential interruption region (46, 48) extends over less than 5% of the total circumference of the support / sealing ring (42, 44).

7. The exhaust gas treatment device according to claim 6, characterized in that, In each support / sealing ring (42, 44) of the at least one support / sealing unit (34), the circumferential interruption region (46, 48) extends over less than 5% of the total circumference of the support / sealing ring (42, 44).

8. The exhaust gas treatment device according to claim 6, characterized in that, In at least one support / sealing ring (42, 44) of the at least one support / sealing unit (34), the circumferential interruption region (46, 48) extends over less than 2% of the total circumference of the support / sealing ring (42, 44).

9. The exhaust gas treatment device according to claim 1 or 2, characterized in that, At least one exhaust treatment element (26, 28) is arranged in the housing (24).

10. The exhaust gas treatment device according to claim 9, characterized in that, The at least one exhaust treatment element (26, 28) includes a catalyst assembly and / or a particulate filter assembly.

11. The exhaust gas treatment device according to claim 2, characterized in that, All the support / sealing rings (42, 44) of the at least one support / sealing unit (34) are constructed identically to each other.

12. An exhaust system for an internal combustion engine, the exhaust system comprising at least one exhaust treatment device (10) according to any one of claims 1 to 11.

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