GB2600783A

GB2600783A - An Exhaust System

Info

Publication number: GB2600783A
Application number: GB2100602.8A
Authority: GB
Inventors: Shelke Kalpesh; Rajgopalan Ananthan; Arora Sanjeev
Original assignee: JC Bamford Excavators Ltd
Current assignee: JC Bamford Excavators Ltd
Priority date: 2020-11-09
Filing date: 2021-01-18
Publication date: 2022-05-11
Also published as: GB202100602D0

Abstract

An exhaust system (26, fig 2) for an internal combustion engine (24, fig 2) of a working machine (10, fig 1) has an exhaust gas treatment device (34, fig 2) comprising a housing 46 defining a device outlet opening 48. A tubular member 54 extends between the exhaust gas treatment device and an exhaust duct 50 downstream of the device outlet opening. A portion of the tubular member is received in the device outlet opening and is radially spaced apart therefrom for allowing exhaust gas to flow therebetween, to reduce exhaust resonance and therefore reduce noise. The tubular member may comprise a flow disruption member such as one or more apertures 55 on a side wall. The exhaust treatment device may be an SCR catalyst.

Description

An Exhaust System

FIELD

The present teachings relate to an exhaust system for an internal combustion engine, an engine system for a working machine and a working machine.

BACKGROUND

Working machines of various types such as excavators, backhoe loaders, wheel loading shovels, telescopic handlers, tractors, material handling and the like used in various applications in construction, agriculture, logistics and waste handling and recycling have historically been powered by internal combustion engines (ICEs), for example diesel engines.

In order to reduce atmospheric pollution caused by the emission of potentially harmful substances from ICEs, such working machines typically include exhaust gas treatment devices such as diesel particulate filters (DPFs) or a selective catalytic reduction (SCR). As exhaust gas flows from the internal combustion engine and through the exhaust treatment device, a pulsed flow is formed in the exhaust outlet which can result in high levels of exhaust noise.

Traditionally, a silencer may be included in the exhaust system, such as a sound absorbing material, e.g. fibreglass, and/or one or more exhaust baffles. However, these known arrangements are often complex and expensive, and can wear resulting in leakages.

The present teachings seek to overcome or at least mitigate one or more problems associated with the prior art.

SUMMARY

A first aspect of the teachings provides an exhaust system for an internal combustion engine of a working machine, the exhaust system comprising an exhaust gas flow path comprising an inlet configured to be coupled to an outlet of an internal combustion engine, and an exhaust gas treatment device positioned along the exhaust gas flow path, the exhaust gas treatment device comprising a housing defining a device outlet opening. The exhaust gas flow path comprises an exhaust duct downstream of the device outlet opening, and a tubular member extending between the exhaust gas treatment device and the exhaust duct. A portion of the tubular member is received in the device outlet opening and is radially spaced apart therefrom for allowing exhaust gas to flow therebetween.

Advantageously, this arrangement reduces exhaust resonance and therefore the level of noise, whilst still treating the exhaust gases produced during combustion.

The exhaust system may further comprise an outlet sleeve extending downstream from the device outlet opening, and the outlet sleeve may surround a portion of the tubular member.

Advantageously, this arrangement further reduces exhaust resonance and therefore the level of noise, by providing an annular cavity between the housing and the tubular member for exhaust gas to flow into.

The outlet sleeve may be radially spaced apart from the tubular member so as to device a cavity therebetween for allowing exhaust gas to flow therebetween.

Advantageously, the radial/annular cavity creates a space for the exhaust gas to occupy prior to entering the tubular member.

The outlet sleeve may be connected to the exhaust duct so as to enclose a downstream end of the cavity.

Advantageously, this has been found to further disrupt exhaust gas flow which further reduces exhaust resonance and therefore the level of noise.

The outlet sleeve may be at least partially formed as a downstream extension of the housing.

The outlet sleeve may be partially formed by an upstream extension of the exhaust duct secured to the downstream extension of the housing.

The outlet sleeve may comprise an enlarged inner diameter region.

Advantageously, this arrangement works to increase the volume of the cavity so as to increase the volume of exhaust gas can be contained within the cavity.

An upstream end of the tubular member may extend into the housing of the exhaust gas treatment device.

Advantageously, this helps to direct a portion of the flow of exhaust gas directly through the tubular member.

The tubular member may extend into the housing of the exhaust gas treatment device by a distance up to the elongate length of the tubular member.

The tubular member may extend into the housing of the exhaust gas treatment device by a distance in the range 12mm to 22mm.

Advantageously, an insertion length within this range has been found to be optimal in reducing noise.

The tubular member may comprise a flow disruption feature configured to disrupt the flow of exhaust gas therethrough.

Advantageously, the flow disruption feature breaks up the formation of any vortices in the flow region and reduces the flow induced noise.

The flow disruption feature may comprise an inlet on a side wall of the tubular member.

Advantageously, this arrangement enables exhaust gas that has travelled between the tubular member and the device outlet opening to flow into the tubular member through the side wall inlet. This arrangement works to further disrupt exhaust gas flow through the tubular member.

The inlet may comprise one or more apertures in the side wall of the tubular member.

Advantageously, the apertures direct the flow of exhaust from the radial spacing and through the tubular member, allowing the exhaust gas to diffuse as it passes through the apertures. This breaks up the formation of any vortices in the flow region and reduces the flow induced noise. Additionally, providing apertures in combination with the radial spacing eliminates the need for additional noise reduction components, such as a baffle and/or shock absorbing material.

The one or more apertures may be arranged in an array, e.g. a regular repeating array.

A first portion of the tubular member positioned within the housing may comprise an array of first apertures, and a second portion of the tubular member downstream of the first portion may comprise an array of second apertures, wherein the first apertures are larger than the second apertures.

Advantageously, this enables a portion of the exhaust gas to diffuse through the first set of apertures prior to entering the device outlet opening, and a portion of the gas to diffuse from the radial spacing. This means there is diffusion happening across the entirety of the tubular member.

Each first aperture may comprise a diameter in the range 0.2mm to 64mm. Each first aperture may comprise a diameter in the range 16mm to 36mm.

Each second aperture may comprise a diameter in the range 0.2mm to 64mm. Each second aperture may comprise a diameter in the rangelmm to 15mm.

Advantageously, this size of aperture has been found optimal to reducing the level of noise by absorbing the specific frequencies responsible for high levels of exhaust noise.

The array or arrays of apertures may be arranged in a circumferentially spaced apart array.

The tubular member may define an internal flow path that is devoid of any obstruction.

Advantageously, providing a tubular members that defines a path or duct that has no obstructions has been found to prevent backflow of the exhaust gas.

The device outlet opening may be positioned substantially centrally on the housing.

The tubular member may be secured, e.g. welded, to the exhaust duct. The tubular member may be formed from sheet metal, e.g. sheet steel. The exhaust treatment device may be an SCR.

A second aspect of the teachings provides an engine system for a working machine, the engine system comprising an internal combustion engine comprising an outlet and an exhaust gas system of the first aspect. The exhaust gas flow path is coupled to the outlet of the internal combustion engine.

A third aspect of the teachings provides a working machine comprising an engine system of the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of a working machine according to an embodiment; Figure 2 is a schematic representation of an engine system of the working machine of Figure 1; Figure 3 is a perspective view of an exhaust system of the working machine of Figure 1; Figure 4 is a cross-sectional side view of a part of the exhaust system of Figure 3; and Figure 5 is perspective view of a tubular member of the exhaust system of Figure 3.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring firstly to Figure 1, there is illustrated a working machine 10 according to an embodiment of the present teachings. In the present embodiment, the working machine is a wheeled excavator, but in alternative embodiments, the working machine 10 may be a backhoe loader, telehandler, tractor, loading shovel or the like.

The working machine 10 includes a body. The body includes an undercarriage 12 and a superstructure 14 mounted to the undercarriage 12. The working machine 10 includes an operator structure 16 from which an operator is able to operate the working machine 10. In some arrangements, the working machine 10 may not include an undercarriage 12 and superstructure 14 and instead may include an operator structure 16 mounted onto a chassis.

In the illustrated embodiment, the superstructure 14 is rotatably mounted to the undercarriage 12, and the operator structure 16 is rotatably mounted to the superstructure 14. In alternative arrangements of the working machine 10, it will be appreciated that the operator structure 16 may not be rotatable relative to the superstructure 14 and/or that the superstructure 14 may not be rotatable relative to the undercarriage 12.

A working arm 18 is rotatably mounted to the superstructure 14 for performing working operations. The working arm 18 is mounted via kingpost arrangement 20.

The working arm 18 has a working implement 19 mounted at the distal end thereof. In the illustrated embodiment, the working implement 19 is a bucket, but in alternative arrangements any suitable working implement may be used such as forks, a shovel, a sweeper, a grapple etc. The undercarriage 12 is connected to a ground engaging structure. The ground engaging structure includes wheels 22a, 22b. The wheels 22a, 22b are mounted to the undercarriage 12 via first and second drive axle assemblies. The second drive axle assembly is fixed with respect to the undercarriage 12, whereas the first drive axle assembly is capable of limited articulation, thereby permitting the wheels to remain in ground contact, even if the ground is uneven. The wheels 22a, 22b are typically provided with off-road pneumatic tyres. In this embodiment, both drive axle assemblies are steer axles, but this may not always be the case. In alternative arrangements, the ground engaging structure may include a pair of endless tracks.

The working machine 10 includes a prime mover. The prime mover is provided in the form of a diesel internal combustion engine 24. The engine 24 is mounted to the undercarriage 12. A heat exchanger and cooling fan are housed in the undercarriage 12 adjacent the engine 24. A fuel tank providing a fuel supply to the engine is positioned on an opposite side of undercarriage to the engine 24.

Referring now to Figure 2, there is shown an engine system 26. The engine system 26 includes an exhaust system 28 and the internal combustion engine 24. The exhaust system 28 defines an exhaust gas flow path. The exhaust gas flow path is coupled to an outlet (not shown) of the internal combustion engine 24.

An exhaust treatment device 34 is positioned along the exhaust flow path. The exhaust treatment device 34 of this embodiment is an SCR, however alternative exhaust treatment devices may be used, for example a NOx absorber catalyst. In this embodiment, the engine system 26 further includes a supply module 36 and a dosing control unit 38. The supply module 36 is connected to a tank 40, which has a solution of urea contained within it.

The engine system 26 includes an exhaust mixer 42 and a dosing module 44.The internal combustion engine 24 is connected to the exhaust mixer 42 and the exhaust mixer 42 is connected to the selective catalytic reducer 34. In this way, exhaust gas can pass from the internal combustion engine 24 to the selective catalytic reducer 34. The tank 40 is connected to the supply module 36 and the supply module is connected to the dosing module 44. In this way, urea solution can pass from the urea tank 40 through the supply module 36 to the dosing module 44. The dosing module 44 is connected to the exhaust mixer 42. In this way, urea solution can be transferred from the dosing module 44 to the exhaust mixer 42 when required.

Although the engine system 26 has been described including an exhaust mixer, a supply module, a dosing control unit and a dosing module, it shall be appreciated that in alternative embodiments these components may be omitted and/or alternative components may be used.

Referring to Figure 3, the exhaust system 28 is illustrated. The exhaust system 28 includes an exhaust gas treatment device 34 and an exhaust gas flow path.

The exhaust gas treatment device 34 has a housing 46. The housing 46 defines a device outlet opening 48. The exhaust gas flow path includes an exhaust duct 50 positioned downstream of the device outlet opening 48. The exhaust treatment device 34 and the device outlet opening 48 are positioned along the exhaust gas flow path such that exhaust gas flows from housing 46 of the exhaust gas treatment device 34 and through the device outlet opening 48 to the exhaust duct 50.

The exhaust gas flow path includes a tubular member 54 extends between the exhaust gas treatment device 34 and the exhaust duct 50 (i.e. between the housing 46 and the exhaust duct 50).

The exhaust flow path is arranged such that exhaust gas flows from the internal combustion engine 24, through the exhaust flow path inlet, into the exhaust gas treatment device 34 to be treated, through the device outlet opening 48, through the tubular member 54, and into the exhaust duct 50 so as to be expelled.

The device outlet opening 48 is arranged substantially centrally on the housing 46. The housing 46 is substantially cylindrical in shape, and defines an internal chamber where the exhaust gas is treated.

The device outlet opening 48 is substantially circular in cross-section. The device outlet opening 48 receives a portion of the tubular member 54 therein. The device outlet opening 48 is arranged so as to surround a part of the tubular member 54 and to be radially spaced apart therefrom.

Referring now to Figures 4 and 5, the device outlet opening 48 defines an outlet sleeve 56. The outlet sleeve 56 extends downstream from the housing 46 of the exhaust gas treatment device 34. Put another way, the outlet sleeve 56 extends downstream from the device outlet opening 48. The outlet sleeve 56 is arranged to surround a portion of the tubular member 54. The outlet sleeve 56 is spaced apart from the tubular member 54 such that a cavity 58 is defined therebetween (i.e. between an outer surface of the tubular member 54 and an inner surface of the outlet sleeve 56). Exhaust gas flowing along the exhaust gas flow path is able to flow into the cavity 58. As will be discussed in more detail below, the exhaust gas that flows into the cavity 58 is able to flow into the tubular member 54 via an inlet provided in a wall of the tubular member 54.

The tubular member 54 is arranged substantially centrally in the device outlet opening 48. Put another way, the tubular member 54 is arranged substantially centrally within the outlet sleeve 56. A central longitudinal axis of the tubular member 54 and a central longitudinal axis of the outlet sleeve 56 are co axially aligned. This central arrangement of the tubular member 54 helps to promote a uniform flow distribution into the tubular member 54.

The outlet sleeve 56 is connected to the exhaust duct 50 so as to enclose the downstream end of the cavity 58. This arrangement ensures all of the exhaust gas diffuses through the inlet on the side wall of the tubular member 54. Enclosing the

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downstream end of the cavity 58 also works to prevent backflow of exhaust gas from the exhaust duct 50 into the cavity 58.

The outlet sleeve 56 is partially formed as a downstream extension 56a of the housing 46. In the illustrated embodiment, the downstream extension 56a of the housing 46 is welded to the housing 46 (i.e. to the device outlet opening 48). In alternative arrangements, however, it will be appreciated that the downstream extension 56b may be integrally formed with the housing 46. The outlet sleeve 56 is partially formed by an upstream extension 56b of the exhaust duct 50. In the illustrated embodiment, the upstream extension 56b of the outlet sleeve 56 is welded to the exhaust duct 50. In alternative arrangements, however, it will be appreciated that the upstream extension 56b may be integrally formed with the exhaust duct 50. The upstream extension of the exhaust duct 50 is secured, e.g. by a clamp or welding etc., to the downstream extension of the housing 46.

The upstream section 56a and the downstream section 56b are mechanically fastened together using a clamp assembly 62, however any suitable fastening may be used. The clamp assembly 62 is secured to an outer surface of the upstream section 56a and an outer surface of the downstream section 56b in order to retain the outlet sleeve 56 in the required position and prevent leakage of exhaust gas to the atmosphere. In alternative embodiments, the outlet sleeve may be an integral component extending from either the housing or the exhaust duct. Alternatively, the sleeve may be made up of any suitable number of sections. The radial protrusion and clamp assembly may be positioned at any location on the outlet sleeve, for example in the centre or towards the upstream end.

The outlet sleeve 56 has a radial protrusion 60 located towards a downstream end of the sleeve. The radial protrusion 60 increases the volume of the radial cavity 58 towards the downstream end. The radial protrusion 60 has a substantially trapezoid cross sectional profile, however it shall be appreciated that any suitable cross sectional shape may be used.

The exhaust duct 50 converges at an upstream end so as define a reduced diameter section. The reduced diameter section connects to the tubular member 54. The reduced diameter section has substantially the same diameter as the tubular member 54.

A portion of the tubular member 54 extends into the housing 46 of the exhaust gas treatment device 34. Put another way, an upstream end of the tubular member 54 extends into the housing 46. In this embodiment, the tubular member 54 extends into the housing 46 by a distance in a range lOmm to 24mm, 12mm to 22mm, for example 15mm to 19mm. In alternative arrangements, the distance the tubular member 54 extends into the housing 46 may be reduced in order to improve the packing. The tubular member may extend into the housing by any distance in a range Omm to the total length of the tubular member.

The tubular member 54 includes a flow disruption feature 55 configured to disrupt the flow of exhaust gas therethrough. The flow disruption feature 55 is provided in the form of an inlet on a side wall of the tubular member 54.The inlet enables exhaust gas within the cavity 58 to flow into the tubular member 54. The inlet is provided in the form of apertures 55 on the side wall of the tubular member 54.

The apertures 55 extend over an entirety of the side wall of the tubular member 54. Providing the apertures 55 extending over the side wall help to increase the volume of exhaust gas that is able to flow from the cavity 58 into the tubular member 54.

The apertures 55 are arranged in an array, e.g. a regular repeating array, on the side wall of the tubular member 54. The array of apertures includes a first array 55a of first apertures and a second array 55b second apertures. However, in alternative embodiments, the apertures may be arranged in a single repeating array (i.e. all of the apertures may be uniformly located over the side wall of the tubular member 54), or any other suitable number of arrays may be provided.

The first array 55a is disposed within the housing 56 of the exhaust gas treatment device 34. This arrangement helps to diffuse a portion of the exhaust gas from the exhaust treatment device 34 straight through the tubular member 54. The second array 55b is arranged downstream from the first array 55a. The second array 55b is surrounded by the outlet sleeve 56. The second array 55b of apertures enable exhaust gas to flow from the cavity 58 into the tubular member 54.

The first array of apertures 55a are arranged in a single circumferentially spaced apart array. However, in alternative embodiments the first array of apertures may be arranged in any number of circumferentially spaced apart rows, similar to the second array of apertures. The second array of apertures 55b are arranged in a series of circumferentially spaced apart uniform rows. There may be any suitable number of rows, for example in the range 6 to 26 rows, or optionally in the range 11 to 21 rows. Whilst the apertures of the first and second arrays 55a, 55b are illustrated to be aligned in rows, in some alternative arrangements the rows of apertures of the first array 55a and/or second array 55b may be rotational offset or staggered.

The apertures of the first array 55a are larger than the apertures of the second array 55b. In alternative embodiments, the apertures of the first array 55a may be the same size as the apertures of the second array 55b. The apertures of the first array 55a and the apertures of the second array 55b may have a diameter in the range of 0.2mm to 64mm.

The apertures of the first array 55a have a diameter in the range of 0.2mm to 64mm. In this embodiment, the apertures of the first array 55a have a diameter in the range 16mm to 36mm, optionally in the range 22mm to 30mm.

The apertures of the second array 55b have a diameter in the range of 0.2mm to 64mm. In this embodiment, the apertures of the second array 55b have a diameter in the range 0.1mm to 15mm, optionally in the range of lmm to 7mm. Whilst the illustrated arrangement provides aperture of the first array 55a that are larger than the apertures of the second array 55b, in some alternative embodiments, the apertures of the first and second arrays 55a, 55b may have diameters that are substantially the same.

The apertures of the first and second arrays 55a, 55b have a circular profile, but it will be appreciated that any suitable shape may be used, such as square hexagonal or any other suitable profile.

The tubular member 54 defines an internal channel 64 that is devoid of any obstruction, for example an exhaust baffle or sound absorbing material. This simplifies the manufacturing and assembly process of the exhaust system 28.

The tubular member 54 is manufactured from a metallic material, for example steel. The tubular member is formed from sheet metal, e.g. sheet steel.

In order to manufacture the tubular member 54, a rectangular metallic sheet is provided with a width corresponding to a required diameter of the tubular member 54. The first and second arrays of apertures 55a, 55b are machined into the outer surface of the sheet. The sheet is subsequently bent into the required tubular shape and welded together along connecting edges.

Although the teachings have been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope as defined in the appended claims.

Claims

Claims 1. An exhaust system for an internal combustion engine of a working machine, the exhaust system comprising: an exhaust gas flow path comprising an inlet configured to be coupled to an outlet of an internal combustion engine; and an exhaust gas treatment device positioned along the exhaust gas flow path, the exhaust gas treatment device comprising a housing defining a device outlet opening; wherein the exhaust gas flow path comprises an exhaust duct downstream of the device outlet opening, and a tubular member extending between the exhaust gas treatment device and the exhaust duct, wherein a portion of the tubular member is received in the device outlet opening and is radially spaced apart therefrom for allowing exhaust gas to flow therebetween.
2. The exhaust system of claim 1, comprising an outlet sleeve extending downstream from the device outlet opening, and wherein the outlet sleeve surrounds a portion of the tubular member.
3. The exhaust system of claim 2, wherein the outlet sleeve is radially spaced apart from the tubular member so as to device a cavity therebetween for allowing exhaust gas to flow therebetween.
4. The exhaust system of claim 3, wherein the outlet sleeve is connected to the exhaust duct so as to enclose a downstream end of the cavity.
5. The exhaust system of any of claims 2 to 4, wherein the outlet sleeve is at least partially formed as a downstream extension of the housing.
6. The exhaust system of claim 5, wherein the outlet sleeve is partially formed by an upstream extension of the exhaust duct secured to the downstream extension of the housing.
7. The exhaust system of any of claims 2 to 6, wherein the outlet sleeve comprises an enlarged inner diameter region.
8. The exhaust system of any preceding claim, wherein an upstream end of the tubular member extends into the housing of the exhaust gas treatment device.
9. The exhaust system of claim 8, wherein the tubular member extends into the housing of the exhaust gas treatment device by a distance up to the elongate length of the tubular member.
10.The exhaust system of claim 9, wherein the tubular member extends into the housing of the exhaust gas treatment device by a distance in the range 12mm to 22mm.
11. The exhaust system of any preceding claim, wherein the tubular member comprises a flow disruption feature configured to disrupt the flow of exhaust gas therethrough.
12.The exhaust system of claim 11, wherein the flow disruption feature comprises an inlet on side wall of the tubular member.
13.The exhaust system of claim 12, wherein the inlet comprises one or more apertures in the side wall of the tubular member.
14. The exhaust system of claim 13, wherein the one or more apertures are arranged in an array, e.g. a regular repeating array.
15.The exhaust system of claim 14, wherein a first portion of the tubular member positioned within the housing comprises an array of first apertures, and a second portion of the tubular member downstream of the first portion comprises an array of second apertures, wherein the first apertures are larger than the second apertures.
16.The exhaust system of claim 15, wherein each first aperture comprises a diameter in the range 0.2mm to 64mm, optionally in the range 16mm to 36mm, and/or wherein each second aperture comprises a diameter in the range 0.2mm to 64mm, optionally in the range lmm to 15mm.
17.The exhaust system of claim 16, wherein each first aperture comprises a diameter in the range 16mm to 36mm, and/or wherein each second aperture comprises a diameter in the range lmm to 15mm.
18.The exhaust system of any one of claims 15 to 17, wherein the array or arrays of apertures are arranged in a circumferentially spaced apart array.
19.The exhaust system of any preceding claim, wherein the tubular member defines an internal flow path that is devoid of any obstruction.
20.The exhaust system of any preceding claim, wherein the device outlet opening is positioned substantially centrally on the housing.
21.The exhaust system of any preceding claim, wherein the tubular member is provided is secured, e.g. welded, to the exhaust dud.
22.The exhaust system of any preceding claim, wherein the tubular member is formed from sheet metal, e.g. sheet steel.
23.The exhaust system of any preceding claim, wherein the exhaust treatment device is an SCR.
24. An engine system for a working machine, the engine system comprising: an internal combustion engine comprising an outlet; an exhaust gas system according to any preceding claim, wherein the exhaust gas flow path is coupled to the outlet of the internal combustion engine.
25.A working machine comprising an engine system according to claim 24.