GB2552060A

GB2552060A - Vehicle exhaust system

Info

Publication number: GB2552060A
Application number: GB1707611.8A
Authority: GB
Inventors: Petley Dean; Fletcher Simon; Mitchley Stephen; Pillinger Jacob
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2016-06-15
Filing date: 2017-05-12
Publication date: 2018-01-10
Anticipated expiration: 2037-05-12
Also published as: GB2553200A; WO2017216105A1; GB201707611D0; DE112017003009T5; GB201709295D0; GB2552060B; GB2553200B; GB201610407D0

Abstract

A vehicle exhaust system (14, Fig. 1) comprising an exhaust system component 18 and a pipe 20 together defining a channel for exhaust gases flowing through the vehicle exhaust system which further comprises a resiliently-biased sealing means 36 having a first sealing surface 44 and a second sealing surface 46; the exhaust system component 18 is physically separated from the pipe 20 by a gap, the sealing means 36 being positioned within said gap such that the first sealing surface 44 is in contact with the exhaust system component 18 and the second sealing surface 46 is in contact with the pipe 20, the sealing means 36 and pipe 20 being arranged with axial overlap, the sealing means 36 being positioned radially inwards of an extension portion of the pipe 20 .

Description

(54) Title of the Invention: Vehicle exhaust system

Abstract Title: Vehicle exhaust system with a resiliently biased sealing means (57) A vehicle exhaust system (14, Fig. 1) comprising an exhaust system component 18 and a pipe 20 together defining a channel for exhaust gases flowing through the vehicle exhaust system which further comprises a resilientlybiased sealing means 36 having a first sealing surface 44 and a second sealing surface 46; the exhaust system component 18 is physically separated from the pipe 20 by a gap, the sealing means 36 being positioned within said gap such that the first sealing surface 44 is in contact with the exhaust system component 18 and the second sealing surface 46 is in contact with the pipe 20, the sealing means 36 and pipe 20 being arranged with axial overlap, the sealing means 36 being positioned radially inwards of an extension portion of the pipe 20 .

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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VEHICLE EXHAUST SYSTEM

TECHNICAL FIELD

The present disclosure relates to a vehicle exhaust system, and particularly, to a sealing means for a vehicle exhaust system. Aspects of the invention relate to a vehicle exhaust system, to a vehicle comprising a vehicle exhaust system and to a method of preventing the escape of exhaust gases from a vehicle exhaust system.

BACKGROUND

Vehicle exhaust systems are configured to control the flow and treatment of exhaust gases that are expelled from a vehicle engine, before the exhaust gases are released into the atmosphere. Vehicle exhaust systems typically comprise an exhaust manifold that is configured to collect exhaust gases from the engine and directs the gases into downstream components of the exhaust system. In particular, the exhaust manifold may be connected to a turbocharger assembly, which, in turn, is connected to a hot end of the exhaust system. Exhaust gases pass through the hot end of the exhaust system, before passing through a cold end of the exhaust system, and the gases are then expelled through an exhaust outlet. The hot end of the exhaust system typically comprises aftertreatment devices, such as a catalytic converter and associated piping.

Typically, the turbocharger assembly and the hot end of the exhaust system are connected by way of a v-band clamp, which is positioned so as to join a flange of the turbocharger assembly to a flange of an adjoining downstream pipe. The two flanges abut one another, and the v-band clamp is arranged in a c-shape around the outside of the flanges such that the flanges are sandwiched between two arms of the clamp. In this way, the v-band clamp draws the turbocharger assembly and the pipe together, compressing the two flanges against one another to prevent the escape of exhaust gases between the turbocharger assembly and the pipe.

In recent years, it has become an objective of vehicle manufacturers to reduce the weight of vehicle components, in order to reduce the use of raw materials and to improve fuel efficiency for environmental and economic benefit. Among others, it is an industry goal to apply lightweighting technologies to components of vehicle exhaust systems.

One way in which the weight of exhaust system components may readily be reduced is by down-gauging the materials used to manufacture the components, such that the walls of the finished components are thinner. While reducing the material gauge of the components of a vehicle exhaust system can lead to significant weight savings, this can also reduce the structural rigidity of the components. In the event that the material gauge of the turbocharger assembly and the adjoining downstream pipe is reduced, for example, the lower structural rigidity of the components may mean that the turbocharger assembly and the pipe are more susceptible to vibrations while the vehicle is in use. Since the flange of the turbocharger and the flange of the pipe are rigidly connected by way of the v-band clamp, vibrations are directly transmitted from one component to the other. In addition, by virtue of the arrangement of the v-band clamp, there is minimal allowance for relative movement between the turbocharger and the pipe, and stresses created by thermal variations in the components may lead to undesirable deformation of the components.

There remains a need to provide a vehicle exhaust system having an improved connection between a turbocharger assembly and a downstream pipe. The present invention has been devised to mitigate or overcome at least some of the abovementioned problems.

SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a vehicle exhaust system comprising an exhaust system component and a pipe, the exhaust system component and the pipe together defining a channel for exhaust gases flowing through the vehicle exhaust system. The vehicle exhaust system further comprises a resiliently-biased sealing means, having a first sealing surface and a second sealing surface, wherein the exhaust system component is physically separated from the pipe by a gap. The sealing means is positioned within said gap such that the first sealing surface is in contact with the exhaust system component about an outlet in the exhaust system component and the second sealing surface is in contact with the pipe, the sealing means being configured to prevent the escape of the exhaust gases from the vehicle exhaust system. The sealing means and the pipe are arranged with axial overlap along the direction of exhaust gas flow, the sealing means being positioned radially inwards of an extension portion of the pipe with which the sealing means has axial overlap.

The exhaust system component may be a turbocharger assembly. Alternatively, the exhaust system component may be an exhaust manifold. The following paragraphs explain the benefits of the present technique principally in terms of a turbocharger assembly, but it should be understood that the same principles and advantages apply to an exhaust manifold, or other exhaust system components.

An arrangement in which a sealing means is positioned between a turbocharger assembly and a pipe allows for some relative movement between the two parts. The sealing means thus permits some thermal expansion of the turbocharger assembly and the pipe, without the creation of undesirable stresses in the components. In addition, such an arrangement advantageously reduces the transmission of vibrations between the turbocharger assembly and the pipe.

In one embodiment, said gap may extend between the turbocharger assembly and the pipe in an axial direction along the direction of exhaust gas flow. Such an arrangement permits relative movement between the turbocharger assembly and the pipe in an axial direction. The axial direction is defined as being a direction parallel to the longitudinal axis of the channel in the region of the sealing means. The entirety of the sealing means may be positioned within said gap.

Advantageously, the sealing means may be a spring-biased sealing means.

The pipe may be an inlet to a hot end of the vehicle exhaust system, the pipe being positioned downstream of the turbocharger assembly. Optionally, the pipe forms part of a catalytic converter assembly of the vehicle exhaust system.

In an embodiment, the vehicle exhaust system comprises at least one additional gap between the turbocharger assembly and the pipe. The at least one additional gap may be between an extension portion of the turbocharger assembly and an inner contact portion of the pipe. This allows for exhaust gases to contact an inner surface of the sealing means.

The turbocharger assembly and the pipe may be arranged with axial overlap along the direction of exhaust gas flow. In an embodiment, the extension portion of the turbocharger assembly is arranged with axial overlap with an extension portion of the pipe.

Optionally, the sealing means and the turbocharger assembly are arranged with axial overlap along the direction of exhaust gas flow. In this case, the sealing means may be positioned radially outwards of the extension portion of the turbocharger assembly, with which the sealing means has axial overlap.

In an embodiment, the sealing means and the pipe are arranged with axial overlap along the direction of exhaust gas flow. In this case, the sealing means may be positioned radially inwards of the extension portion of the pipe, with which the sealing means has an axial overlap. The sealing means may be positioned between the extension portion of the turbocharger assembly and the extension portion of the pipe.

The sealing means may be a seal. In an embodiment, the seal may have a bellows configuration. For example, the seal may have a bellows configuration in radial crosssection. Advantageously, a seal having a bellows configuration is able to deform from an original shape under pressure, and to recover the original shape on release of that pressure.

In the event that the seal has a bellows configuration, the seal may have a radial cross-section comprising two or more opposed c-shaped portions connected to one another. In this case, the orientation of the c-shaped portions may alternate so that adjacent c-shaped portions are facing in opposed directions.

Advantageously, the c-shaped portions at the first sealing surface and at the second sealing surface may be oriented such that the first and second sealing surfaces are compressed against the turbocharger assembly and the pipe, respectively, by the exhaust gases, in use. This assists in increasing the effectiveness of the seal between the first sealing surface and the turbocharger assembly, and between the second sealing surface and the pipe.

The entirety of the turbocharger assembly may be physically separated from the entirety of the pipe in a region defining the channel. The turbocharger assembly may be in contact with the pipe elsewhere (i.e. other than in the channel region). Alternatively, the turbocharger assembly and the pipe may be physically separated in their entirety.

Optionally, the sealing means forms a closed ring. The sealing means may be in a state of compression. Advantageously, the first sealing surface of the seal thus applies pressure to the turbocharger assembly, and the second sealing surface of the seal applies pressure to the pipe.

According to another aspect of the invention, there is provided a method of preventing the escape of exhaust gases from a vehicle exhaust system, the method comprising the step of arranging a turbocharger assembly and a pipe such that the turbocharger assembly and the pipe together define a channel for the exhaust gases flowing through the vehicle exhaust system. A resiliently-biased sealing means is positioned within a gap that physically separates the turbocharger assembly and the pipe, the sealing means having a first sealing surface and a second sealing surface. The sealing means is positioned such that the first sealing surface is in contact with the turbocharger assembly and the second sealing surface is in contact with the pipe.

According to another aspect of the invention, there is provided a vehicle comprising a vehicle exhaust system in accordance with a previous aspect of the invention.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic plan view of a vehicle having a vehicle exhaust system of an embodiment of the invention;

Figure 2 is a perspective view of the vehicle exhaust system of Figure 1;

Figure 3 is a perspective view of a sealing means of the vehicle exhaust system of Figure 1;

Figure 4a is a side view of a turbocharger assembly of the vehicle exhaust system of Figure 1;

Figure 4b is a side view of the sealing means of Figure 3, in an ‘in use’ position with respect to the turbocharger assembly of Figure 4a;

Figure 5 is a perspective view of a pipe of the vehicle exhaust system of Figure 1;

Figure 6 is a schematic section view of the sealing means of Figure 3, in an ‘in use’ position with respect to the turbocharger assembly of Figure 4a and the pipe of Figure 5; and

Figure 7 is a side view of the sealing means of Figure 3, in an ‘in use’ position with respect to the turbocharger assembly of Figure 4a and the pipe of Figure 5.

DETAILED DESCRIPTION

Figure 1 is a schematic view of a vehicle 10, comprising an engine 12 that is connected to a vehicle exhaust system 14. Referring to both Figure 1 and Figure 2, as is conventional, the vehicle exhaust system 14 comprises an exhaust gas manifold 16 that is fluidly connected to a turbocharger assembly 18. The turbocharger assembly 18 is itself connected to a pipe 20, or inlet of a hot end 22 of the exhaust system 14, which transitions into a cold end 24 of the vehicle exhaust system 14. The hot end 22 of the vehicle exhaust system 14 comprises a catalytic converter assembly 26, a resonator 28 and a chamber 30 for selective catalytic reduction (SCR). The cold end 24 of the vehicle exhaust system 14 comprises two mufflers 32 and a number of connecting pipes, including two tail pipes 34. In the present invention, the turbocharger assembly 18 and the catalytic converter assembly 26 are arranged so as to define a channel 35 (shown in Figure 6) for exhaust gases flowing through the vehicle exhaust system 14.

When the vehicle 10 is in use, exhaust gases are produced in the engine 12. These exhaust gases are expelled from the engine 12 and are collected in the exhaust gas manifold 16, before passing through the downstream components of the vehicle exhaust system 14 and being released through the tail pipes 34 into the atmosphere. The vehicle exhaust system 14 is configured so as to guard against the release of exhaust gases before the exhaust gases have passed through the entirety of the vehicle exhaust system 14, to ensure that the exhaust gases are treated prior to their discharge into the atmosphere.

For this purpose, the vehicle exhaust system 14 comprises a number of sealing means that are configured to guard against the release of exhaust gases between adjoining components of the vehicle exhaust system 14. In particular, referring to Figures 1 to 3, the vehicle exhaust system 14 comprises a resiliently-biased seal 36, that is positioned between the turbocharger assembly 18 and the catalytic converter assembly 26 of the vehicle exhaust system 14, to guard against the escape of exhaust gases therebetween.

As is shown most clearly in Figure 3, the seal 36 is in the form of an annular ring, having a bellows configuration in radial cross-section, such that the seal 36 is springbiased. The cross-section of the seal comprises two or more opposed c-shaped portions 38 connected to one another, such that the orientation of the c-shaped portions 38 alternates. Typically, the seal 36 comprises five opposed c-shaped portions 38 in a ‘multiple bellows’ configuration, although the skilled person would appreciate that the number of opposed c-shaped portions 38 could be less than or greater than five, depending on the desired dimensions and properties of the seal 36. Referring to Figure 6, the seal 36 comprises an inner surface 40, an outer surface 42, a first sealing surface 44 and a second sealing surface 46. In use, the inner surface 40 of the seal 36 is exposed to exhaust gases passing through the vehicle exhaust system 14, and the outer surface 42 of the seal 36 is exposed to the external environment.

The seal 36 is typically manufactured using a nickel alloy, such as Inconel®, and may be subjected to a heat treatment process to increase the ability of the seal 36 to recover its shape after deformation. Alternatively, the seal 36 may be manufactured from Waspaloy® or any other suitable nickel alloy, or from stainless steel. The seal 36 is capable of cyclic use, and can be used at high temperatures and pressures. A coating, such as silver, may also be applied to the seal 36 to improve the sealing performance of the seal 36.

Referring to Figures 4a and 4b, the turbocharger assembly 18 comprises an outer contact portion 48 and an extension portion 50. The extension portion 50 takes the form of an annular ring and extends from the outer contact portion 48 in an axial direction, so as to define an outlet 52 for exhaust gases from the turbocharger assembly 18. In an example, the outer contact portion 48 and the extension portion 50 may be manufactured by means of a casting process. Alternatively, the outer contact portion 48 and the extension portion 50 may be manufactured by way of machining. As can be seen in Figure 4b, which shows the seal 36 in situ, the diameter of the seal 36 is greater than the diameter of the extension portion 50 so that the extension portion 50 can be received within the seal 36, i.e. allowing the seal 36 to be located around the extension portion 50. In use, the seal 36 is thus positioned radially outwards of the extension portion 50 of the turbocharger assembly 18.

As shown in Figure 5, in the present invention the inlet 20 of the hot end 22 of the vehicle exhaust system 14 forms part of the catalytic converter assembly 26 of the vehicle exhaust system 14. The inlet 20 comprises a main body 53, an inner contact portion 54 in the form of an annulus, and an extension portion 56. The extension portion 56 of the inlet 20 extends from the inner contact portion 54 in an axial direction, forming a lip. The diameter of the seal 36 (shown in Figure 6) is smaller than the diameter of the extension portion 56 of the inlet 20, such that the seal 36 can be received within and hence positioned radially inwards of the extension portion 56 of the inlet 20.

Referring to Figures 6 and 7 the turbocharger assembly 18 and the catalytic converter assembly 26 are arranged with a gap or space 58 therebetween so that they are physically separated. Typically, the turbocharger assembly 18 and the inlet 20 of the catalytic converter assembly 26 are arranged such that the gap 58 extends axially between the outer contact portion 48 of the turbocharger assembly 18 and the inner contact portion 54 of the inlet 20 of the catalytic converter assembly 26, along the direction of exhaust gas flow. The seal 36 is positioned in the gap 58, such that the first sealing surface 44 of the seal 36 is in contact with the outer contact portion 48 of the turbocharger assembly 18 and the second sealing surface 46 of the seal 36 is in contact with the inner contact portion 54 of the inlet 20. In this way, the seal 36 bridges the gap 58 between the turbocharger assembly 18 and the catalytic converter assembly 26, but importantly the turbocharger assembly 18 and the catalytic converter assembly 26 do not make contact.

The seal 36 is positioned in the gap 58 between the extension portion 50 of the turbocharger assembly 18 and the extension portion 56 of the inlet 20 of the catalytic converter assembly 26. By virtue of the extension portion 50 of the turbocharger assembly 18 and the extension portion 56 of the inlet 20, the turbocharger assembly 18, the inlet 20 and the seal 36 are arranged with axial overlap along the direction of exhaust gas flow. In particular: a portion of the seal 36 has axial overlap with the extension portion 50 of the turbocharger assembly 18; a portion of the seal 36 has axial overlap with the extension portion 56 of the inlet 20; and, at least a portion of the extension portion 56 of the inlet 20 has axial overlap with at least a portion of the extension portion 50 of the turbocharger assembly 18. In other words, the extension portion 56 lies radially outward of the seal 36 and the extension portion 50 lies radially inward of the seal 36.

In the depicted embodiment, a second gap 60 is defined between the extension portion 56 of the inlet 20 and a facing portion of the outer contact portion 48 of the turbocharger assembly 18, such that the second gap 60 extends in an axial direction along the direction of exhaust gas flow. In addition, a third gap 62 is defined between the extension portion 50 of the turbocharger assembly 18 and a transition region between the main body 53 and the inner contact portion 54 of the inlet 20, such that the third gap 62 also extends in an axial direction along the direction of exhaust gas flow. The third gap 62 defines an inlet to the gap 58 between the turbocharger assembly 18 and the inlet 20 and permits exhaust gases to be diverted from the channel 35 to pass between the turbocharger assembly 18 and the inlet 20 of the catalytic converter assembly 26. This creates a region of high pressure exhaust gases at the inner surface 40 of the seal 36, such that a pressure gradient exists across the seal 36.

Typically, the c-shaped portions 38 of the seal 36 are oriented such that pressure applied to the inner surface 40 of the seal 36 by the exhaust gases compresses the first and second sealing surfaces 44, 46 against the turbocharger assembly 18 and the inlet 20 of the catalytic converter assembly 26, respectively. Such an arrangement improves the effectiveness of the seal 36 as a mechanism for preventing the escape of exhaust gases between the turbocharger assembly 18 and the catalytic converter assembly 26.

As in a conventional assembly, the turbocharger assembly 18 is rigidly bolted to the engine 12 of the vehicle 10, and the catalytic converter assembly 26 is similarly rigidly fixed in position in the vehicle 10. In the present invention, the turbocharger assembly 18 and catalytic converter assembly 26 are typically physically separated in their entirely, such that the only connection between the turbocharger assembly 18 and the catalytic converter assembly 26 is by way of the seal 36. Since the seal 36 is positioned between the turbocharger assembly 18 and the catalytic converter assembly 26, the seal 36 does not constrain the turbocharger assembly 18 and the catalytic converter assembly 26 to a fixed position relative to one another. In fact, the bellows configuration of the seal 36 allows the seal 36 to deform under compressive loads, such that the seal 36 can accommodate relative movement between the turbocharger assembly 18 and the catalytic converter assembly 26 without compromising the integrity of the seal 36.

The seal 36 thus allows for some thermal expansion of the turbocharger assembly 18 and catalytic converter assembly 26 without risk of distortion of the components of the assemblies 18, 26 or the creation of undesirable stresses in the vehicle exhaust system 14. If anything, expansion of the components and the resultant reduction in the size of the gap 58 between the outer contact portion 48 of the turbocharger assembly 18 and the inner contact portion 54 of the catalytic converter assembly 26 increases the sealing strength of the seal 36, by increasing the force applied by the first and second sealing surfaces 44, 46 to the outer contact portion 48 and inner contact portion 54, respectively. In addition, the seal 36 has a damping effect, reducing the transmission of vibrations between the turbocharger assembly 18 and the catalytic converter assembly 26.

The ability of the seal 36 to change shape without being permanently deformed allows for relatively low, or loose, machining tolerances to be applied during the manufacture and assembly of the turbocharger assembly 18 and the catalytic converter assembly 26. In other words, the seal 36 compensates for some variation in the size of the components of the turbocharger assembly 18 and the catalytic converter assembly 26. In this way, the seal 36 accommodates tolerance stacks that may result from the manufacture and assembly of components of the vehicle exhaust system 14.

Many modifications may be made to the above examples without departing from the scope of the present invention as defined in the accompanying claims.

For example, the skilled person would appreciate that the seal 36 may be positioned between any two adjacent components of the vehicle exhaust system 14, where the adjacent components define a gap therebetween. In addition, it would be appreciated by the skilled person that the seal 36 may be positioned in a gap between the turbocharger assembly 18 and any adjacent downstream inlet, and that the invention is not intended to be restricted to an inlet 20 of a catalytic converter assembly 26.

In addition, the skilled person would understand that the third gap 62 is not restricted to a position between the extension portion 50 of the turbocharger assembly 18 and the inner contact portion 54 of the catalytic converter assembly 26. The third gap 62 may be in any suitable position so as to allow for exhaust gases to flow towards and impinge upon the inner surface 40 of the seal 36. Further, the second gap 60 and the third gap 62 may extend in a direction that is transverse to the axial direction, for example, if the extension portion 56 of the inlet 20 of the catalytic converter assembly 26 is offset from the outer contact portion 48 of the turbocharger assembly 18, or if the extension portion 50 of the turbocharger assembly 18 is offset from the inner contact portion 54 of the catalytic converter assembly 26.

It would be appreciated by the skilled person that the sealing means can take one of a number of forms. For example, the sealing means may be a seal having a radial crosssection in the form of a u-shape, or in the form of a circle. Alternatively, the sealing means may be in the form of a compressible sealant. The bellows configuration shown in the accompanying figures is therefore just one example.

Claims

1. A vehicle exhaust system comprising:

an exhaust system component and a pipe, the exhaust system component and the pipe together defining a channel for exhaust gases flowing through the vehicle exhaust system; and a resiliently-biased sealing means, having a first sealing surface and a second sealing surface, wherein the exhaust system component is physically separated from the pipe by a gap, the sealing means being positioned within said gap such that the first sealing surface is in contact with the exhaust system component about an outlet in the exhaust system component and the second sealing surface is in contact with the pipe, the sealing means being configured to prevent the escape of the exhaust gases from the vehicle exhaust system; and wherein the sealing means and the pipe are arranged with axial overlap along the direction of exhaust gas flow, the sealing means being positioned radially inwards of an extension portion of the pipe with which the sealing means has axial overlap.

2. A vehicle exhaust system according to claim 1, wherein the exhaust system component is a turbocharger assembly.

3. A vehicle exhaust system according to claim 1, wherein the exhaust system component is an exhaust manifold.

4. The vehicle exhaust system of any preceding Claim, wherein said gap extends between the exhaust system component and the pipe in an axial direction along the direction of exhaust gas flow.

5. The vehicle exhaust system of any preceding Claim 1, wherein the entirety of the sealing means is positioned within said gap.

6. The vehicle exhaust system of any preceding claim, wherein the sealing means is a spring-biased sealing means.

7. The vehicle exhaust system of any preceding claim, wherein the pipe is an inlet to a hot end of the vehicle exhaust system, the pipe being positioned downstream of the exhaust system component.

8. The vehicle exhaust system of Claim 7, wherein the pipe forms part of a catalytic converter assembly of the vehicle exhaust system.

9. The vehicle exhaust system of any preceding claim, further comprising at least one additional gap between the exhaust system component and the pipe.

10. The vehicle exhaust system of any preceding claim, wherein the exhaust system component and the pipe are arranged with axial overlap along the direction of exhaust gas flow.

11. The vehicle exhaust system of any preceding claim, wherein the sealing means and the exhaust system component are arranged with axial overlap along the direction of exhaust gas flow.

12. The vehicle exhaust system of Claim 11, wherein the sealing means is positioned radially outwards of an extension portion of the exhaust system component with which the sealing means has axial overlap.

13. The vehicle exhaust system of any preceding claim, wherein the sealing means is a seal having a bellows configuration.

14. The vehicle exhaust system of Claim 13, wherein the seal has a radial crosssection comprising two or more opposed c-shaped portions connected to one another.

15. The vehicle exhaust system of Claim 14, wherein the c-shaped portions at the first sealing surface and at the second sealing surface are oriented such that the first and second sealing surfaces are compressed against the exhaust system component and the pipe, respectively, by the exhaust gases flowing through the vehicle exhaust system, in use.

16. The vehicle exhaust system of any preceding claim, wherein the entirety of the exhaust system component is physically separated from the entirety of the pipe in a region defining the channel.

17. The vehicle exhaust system of any preceding claim, wherein the sealing means forms a closed ring surrounding the channel.

18. The vehicle exhaust system of any preceding claim, wherein the sealing means is in a state of compression.

19. A method of preventing the escape of exhaust gases from a vehicle exhaust system, the method comprising the steps of:

arranging an exhaust system component and a pipe such that the exhaust system component and the pipe together define a channel for the exhaust gases flowing through the vehicle exhaust system; and positioning a resiliently-biased sealing means, having a first sealing surface and a second sealing surface, within a gap that physically separates the exhaust system component and the pipe, such that the first sealing surface is in contact with the exhaust system component and the second sealing surface is in contact with the Pipe, wherein the sealing means and the pipe are arranged with axial overlap along the direction of exhaust gas flow, the sealing means being positioned radially inwards of an extension portion of the pipe with which the sealing means has axial overlap..

20. A vehicle comprising the vehicle exhaust system as claimed in any of Claims 1 to 18.

Intellectual

Property

Office

Application No: GB1707611.8