Exhaust stackpipe
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- AGCO INT GMBH
- Filing Date
- 2024-07-22
- Publication Date
- 2026-06-24
Smart Images
Figure IB2024057092_20022025_PF_FP_ABST
Abstract
Description
EXHAUST STACKPIPEFIELD
[0001] Embodiments of the present disclosure relate generally to an exhaust stackpipe for a vehicle, especially an agricultural vehicle.BACKGROUND
[0002] FIG.l illustrates an example agricultural vehicle in the form of a tractor 100. The tractor 100 comprises a chassis 101 on which are mounted front wheels 102 and rear wheels 103. An engine enclosure 104 towards the front of the tractor 100 encloses an engine and associated components. A cab 106 is located towards a rear of the tractor 100 behind the engine enclosure 104. The engine is connected to an exhaust stackpipe 105. The exhaust stackpipe 105 may serve a variety of purposes, such as controlling noise, directing exhaust fumes away from a driver or other occupant in the cab and improving the performance of the engine.
[0003] The exhaust stackpipe 105 is typically oriented vertically and located in front of and to one side of the cab 106. Since the engine is connected to the exhaust stackpipe 105, the engine may induce vibrations in the exhaust stackpipe 105. As the exhaust stackpipe 105 may be mounted adjacent the cab 106 of the tractor 100, vibrations from the exhaust stackpipe 105 may be transmitted to the cab 106, causing discomfort to a driver present in the cab 106.BRIEF SUMMARY
[0004] In a first aspect of the invention there is provided an exhaust stackpipe for a vehicle, comprising: an exhaust pipe; a heatshield surrounding the exhaust pipe; a plurality of connectors extending between the heatshield and an external surface of the exhaust pipe and connecting the heatshield to the exhaust pipe; and a mass-spring damper attached to the heatshield, wherein a damping frequency of the mass-spring damper is matched to a resonant frequency of the exhaust stackpipe.
[0005] In some embodiments, the mass-spring damper is attached to the heatshield between adjacent ones of the plurality of connectors.
[0006] In some embodiments, the mass-spring damper is contained within a recess in the heatshield.
[0007] In some embodiments, the mass-spring damper is contained within a relief structure extending from an exterior of the heatshield.
[0008] In some embodiments, the mass-spring damper comprises a mass coupled to the housing by first and second spring elements.
[0009] In some embodiments, the first and second spring elements comprise cables aligned parallel to a longitudinal axis of the exhaust pipe.
[0010] In some embodiments, the first and second spring elements comprise springs aligned parallel to a longitudinal axis of the exhaust pipe. The first and second spring elements may be compression springs. The first and second spring elements may be conical springs.
[0011] In some embodiments, the mass-spring damper comprises a third spring element coupling the mass to the housing, the third spring element aligned orthogonally to the first and second spring elements.
[0012] In some embodiments the third spring element comprises a cable.
[0013] In some embodiments the third spring element comprises a stack of Belleville washers compressible in a direction aligned orthogonally to the longitudinal axis of the exhaust Pipe.
[0014] In some embodiments, the mass-spring damper has a damping frequency of between 30 and 120 Hz.
[0015] In some embodiments, the exhaust stackpipe comprises a plurality of massspring dampers attached to the heatshield.
[0016] In some embodiments, each one of the plurality of mass-spring dampers is configured to damp a different resonant frequency.
[0017] According to a second aspect there is provided a vehicle comprising an exhaust stackpipe according to the first aspect.
[0018] In some embodiments, the exhaust stackpipe is mounted vertically relative to an upright orientation of the vehicle.
[0019] In some embodiments, the vehicle is an agricultural vehicle and may be a tractor comprising a cab adjacent the exhaust stackpipe.
[0020] Within the scope of this application it should be understood that the various aspects, embodiments, examples and alternatives set out herein, and individual features thereof may be taken independently or in any possible and compatible combination. Where features are described with reference to a single aspect or embodiment, it should be understood that such features are applicable to all aspects and embodiments unless otherwise stated or where such features are incompatible.BRIEF DESCRIPTION OF THE DRAWINGS
[0021] One or more embodiments of the invention / disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0022] FIG. 1 is a schematic drawing of an example agricultural vehicle;
[0023] FIG. 2 is a schematic drawing of an exhaust stackpipe adjacent a cab of an agricultural vehicle;
[0024] FIGs. 3a and 3b illustrate schematically alternative solutions to reducing vibrations in an exhaust stackpipe;
[0025] FIG. 4 is a schematic drawing of an example exhaust stackpipe comprising massspring dampers;
[0026] FIG. 5 is a schematic drawing of an example mass-spring damper for the exhaust stackpipe of FIG. 4; and
[0027] FIG. 6 is a schematic drawing of an alternative example mass-spring damper for the exhaust stackpipe of FIG. 4.DETAILED DESCRIPTION
[0028] FIG. 2 illustrates an example exhaust stackpipe 200 for an agricultural vehicle. The exhaust stackpipe comprises an exhaust pipe 201 and a heatshield 204 surrounding the exhaust pipe 201 between an inlet 202 and an outlet 203 of the exhaust pipe 201. The heatshield 204 may be formed from sheet metal capable of withstanding extended periods at temperaturesin excess of 100°C and acts to partially insulate the exhaust pipe 201, operating at higher temperatures. A plurality of connectors 205a-d extend between the heatshield 204 and an external surface of the exhaust pipe 201 and connect the heatshield 204 to the exhaust pipe 201. An inlet 202 of the exhaust pipe 201 is connected to an exhaust system 207. The exhaust system 207 may comprise an exhaust gas aftertreatment system configured to reduce pollutant levels in the exhaust gas.
[0029] The exhaust stackpipe 200 may be mounted adjacent to a cab 106 of the agricultural vehicle, for example as shown in FIG. 1. Other mounting positions of the exhaust assembly 200 relative to other components of the vehicle are also possible. Similarly, in the example of FIG.2 the exhaust stackpipe 200 is mounted with an axis 206 of the exhaust pipe 201 oriented substantially vertically relative to an upright orientation of the vehicle. Other orientations are also possible.
[0030] The exhaust stackpipe 200 is generally only connected to the exhaust system 207 at a single point around the inlet 202 of the exhaust pipe 201. During operation of the vehicle, multiple modes of vibration 209 may be set up along the stackpipe 200 by the engine and by movement of the vehicle. This may result in resonant frequencies being excited within the heatshield 204. Lower frequency vibrations (e.g. less than 30 Hz) may cause visible movement of the stackpipe 200 to the driver 208. Higher frequency vibrations (e.g. around 80 Hz to 120 Hz) may result in increased audible noise to the driver 208.
[0031] One possible solution is to increase the number of connectors 205a-d joining the exhaust pipe 201 to the heatshield 204, which will have the effect of stiffening the assembly and raising the resonant frequencies of the exhaust stackpipe 200. An example stackpipe 300a is illustrated schematically in FIG. 3a, in which the number of connectors 305 joining the exhaust pipe 201 to the heatshield is increased. Multiple fixing points along the length of the stackpipe 300a are provided, in which the inner exhaust pipe 201 is connected to the outer heatshield 204 with brackets and welded nuts forming the connectors 305. The heatshield 204 is connected to the nuts by screws passing through multiple holes in the heatshield 204 that are screwed into the nuts. This arrangement will, however, increase the number of parts and processes required in manufacturing the stackpipe 300a.
[0032] Another solution is to attach higher density panels 310 to the heatshield 204 between adjacent connectors 305, as illustrated schematically in FIG. 3b. The panels 310 may for example be provided using bituminous material affixed to the inner or outer surface of the heatshield 204. The bituminous material may for example be self-adhesive, magnetic or affixed to the heatshield 204 with screws. The effect of this will be to stiffen the heatshield and raise the fundamental resonant frequencies of the heatshield, while also lowering the fundamental flexural frequency of the stackpipe 300b through the increased mass. This approach will, however, inevitably add unnecessary weight to the exhaust stackpipe 200.
[0033] FIG. 4 illustrates an example exhaust stackpipe 400 for an agricultural vehicle. Similar to the exhaust stackpipe 200 of FIG. 2, the exhaust stackpipe 400 comprises an exhaust pipe 201 and a heatshield 204 surrounding the exhaust pipe 201 between an inlet 202 and an outlet 203 of the exhaust pipe 201. The exhaust stackpipe 400 also comprises a plurality of connectors 205a-d extending between the heatshield 204 and an external surface of the exhaust pipe 201 and connecting the heatshield 204 to the exhaust pipe 201. The exhaust stackpipe 400 further comprises a plurality of mass-spring dampers 401a-d attached to the heatshield 204. One or more of the mass-spring dampers, e.g. dampers 401b, 401c, may be attached to the heatshield 204 between adjacent connectors 205a-d. In some examples the exhaust stackpipe 400 may comprise a single mass spring damper. Each mass-spring damper 401a-d has a resonant frequency matched to a resonant frequency of the exhaust stackpipe 400.
[0034] In the example of FIG. 4, each mass spring damper 401a-d is contained within a recess 402a-d in the heatshield 204. The outward appearance of the exhaust stackpipe 400 may therefore be similar to a conventional stackpipe. In alternative examples, each mass-spring damper 401a-d may be contained within a relief structure extending from the exterior of the heatshield 204, which may for example be advantageous for retro-fitting to an existing stackpipe. Where a plurality of mass-spring dampers 401a-d is used, each may be configured to damp a different resonant frequency. For example, any one of the plurality of mass spring dampers 401a- d may have a damping frequency of between around 30 and 120 Hz. The resonant frequencies of the heatshield 204 may be determined by analysing the mass and stiffness of the heatshield 204, along with the position of the connectors 205a-d. Tuning each of the mass-spring dampers401a-d to damp a particular resonant frequency of the heatshield 204 allows targeted damping of resonant frequencies excited within the heatshield 204.
[0035] FIG. 5 illustrates a more detailed schematic cutaway view of an example massspring damper 401 mounted within a recess 402 of the housing 204. The mass-spring damper 401 comprises a mass 402 coupled to the housing 204 of the exhaust stackpipe by first and second spring elements, which in this example comprises first and second cables 404a, 404b aligned parallel to the longitudinal axis 206 of the exhaust pipe 201. The first and second spring elements 404a, 404b may alternatively be described as being aligned parallel with a general direction of flow of exhaust gas through the exhaust pipe. Where the exhaust stackpipe is aligned vertically, the first and second spring elements 404a, 404b may alternatively be described as being aligned vertically. The first and second cables 404a, 404b are connected to the housing 204 at respective first and second connection points 403a, 403b. The connection points 403a, 403b may be provided by crimped or welded connectors at an end of each cable 404b.
[0036] The mass-spring damper 401 in this example further comprises a third spring element coupling the mass 402 to the housing 204, the third spring element comprising a third cable 404c aligned orthogonally to the first and second spring elements. The third cable 404c is connected to the housing 204 at a third connection point 403c, which may also be provided by a crimped or welded connector at an end of the cable 404c. In other examples, any or all of the spring elements 404a-c may comprise springs instead of cables 404a-c. Examples of springs for the spring elements 404a-c include helical compression springs, which may have a uniform or tapered (e.g. conical) section. The spring elements 404a-c may alternatively comprise stacks of Belleville washers. Having the third spring element aligned orthogonally to the first and second spring elements allows the mass spring damper 301a to damp resonant frequencies vibrating in both the direction parallel to the external surface of the exhaust pipe 201 and the direction orthogonal to the longitudinal axis 206 of the exhaust pipe 201. Further spring elements may be provided to connect the mass 402 to the housing in other directions. The mass 402 may be provided by a metallic sphere or another metallic shape. The mass may be different for different mass-spring dampers 401 to cover different specific frequencies. The mass 402 may have apassage through which a fixing element passes, securing the spring elements 404a, 404b to the mass 402.
[0037] Depending on the number and orientation of the spring elements 404a-c the mass-spring damper 401 may have various different modes of vibration where the mass oscillates in different directions at different frequencies. The frequency and direction of oscillation can be selected by selecting the number and stiffness of the spring elements 404a-c. Having two spring elements, e.g. spring elements 404a, 404b, allows the mass 402 to oscillate along a first axis 501 substantially orthogonal to the longitudinal axis 206 of the exhaust pipe 201, thereby damping vibrations at a resonant frequency of this oscillation corresponding to flexural resonant modes of the stackpipe. Adding the third spring element 404c or further spring elements will restrict these oscillations further.
[0038] Each of the plurality of mass-spring dampers 401a-d may be configured to damp a different resonant frequency. The resonant frequency of each of the plurality of mass-spring dampers 401a-d may be tuned by, for example, changing the mass value of the mass 402 or the stiffness of each of the first, second and third spring elements 404a-c. The resonant frequency of each of the plurality of mass-spring dampers 401a-d may each be tuned to correspond to a different resonant frequency. Alternatively, the resonant frequency of each of the plurality of mass-spring dampers 401a-d may each be tuned to correspond to substantially the same resonant frequency.
[0039] The mass 402 may be a sphere. The mass 402 may be constructed from metal. The mass 402 may also be constructed from other materials. The material choice for the mass 402 may be based on temperature requirements, such as the ability to withstand heat transferred from the exhaust pipe 201 to any one of the plurality of mass-spring dampers 301a- d. For example, the mass 402 may be constructed of a material capable of withstanding extended exposure to a temperature of 100°C or above.
[0040] FIG. 6 illustrates an example arrangement for a mass-spring damper 601, in which the first and second spring elements 604a, 604b are conical helical springs connected between connectors 603a, 603b and a mass 602. A fixing element 606, which may be in the form of a threaded bolt, extends between the connectors 603a, 603b and passes through a passage606 through the mass 602. The mass is able to oscillate in a direction parallel to the longitudinal axis of the exhaust pipe, which in this case is vertically, between the connectors, sliding along the fixing element 605. The third spring 604c is in the form of a stack of Belleville springs connected between a third connector 603c and the mass 602. Other arrangements and combinations of springs are also envisaged, depending on the application and damping requirements and it should be appreciated that elements from one embodiment may be adopted in another.
[0041] Whilst embodiments of the disclosure have been described with reference to an agricultural vehicle in the form of a tractor, the teaching herein can be applied to a range of vehicles, including other agricultural vehicles, other utility vehicles such as are used in the construction industry and road trucks.
[0042] All references cited herein are incorporated herein in their entireties. If there is a conflict between definitions herein and in an incorporated reference, the definition herein shall control.
Claims
CLAIMS1. An exhaust stackpipe (400) for a vehicle (100), comprising: an exhaust pipe (201); a heatshield (204) surrounding the exhaust pipe (201); a plurality of connectors (205a-d) extending between the heatshield (204) and an external surface of the exhaust pipe (201) and connecting the heatshield (204) to the exhaust pipe (201); and a mass-spring damper (401a-d) attached to the heatshield (204), wherein a damping frequency of the mass-spring damper (401a-d) is matched to a resonant frequency of the exhaust stackpipe (400).
2. The exhaust stackpipe (400) of claim 1, wherein the mass-spring damper (401a-d) is attached to the heatshield (204) between adjacent ones of the plurality of connectors (205a-d).
3. The exhaust stackpipe (400) of claim 1 or claim 2, wherein the mass-spring damper (401a-d) is contained within a recess (402a-d) in the heatshield (204).
4. The exhaust stackpipe (400) of claim 1 or claim 2, wherein the mass-spring damper (401a-d) is contained within a relief structure extending from an exterior of the heatshield (204).
5. The exhaust stackpipe (400) of any preceding claim, wherein the mass-spring damper (401a-d) comprises a mass (402) coupled to the housing (204) by first and second spring elements (404a, 404b).
6. The exhaust stackpipe (400) of claim 5, wherein the first and second spring elements are aligned parallel to a longitudinal axis (206) of the exhaust pipe (201).
7. The exhaust stackpipe (400) of claim 5 or claim 6, wherein the mass-spring damper (401a-d) comprises a third spring element (404c) coupling the mass (402) to the housing (204), the third spring element aligned orthogonally to the first and second spring elements (404a, 404b).
8. The exhaust stackpipe (400) of claim 5 or claims 6 wherein the first and second spring elements are selected from the group comprising cables (404a, 404b) and springs (604a, 604b).
9. The exhaust stackpipe (400) of claim 8, wherein the third spring element is selected from the group comprising: a cable (404c) and a stack of Bellville washers (604c).
10. The exhaust stackpipe (400) of any preceding claim, wherein the mass-spring damper (401a-d) has a damping frequency of between 30 and 120 Hz.
11. The exhaust stackpipe (400) of any preceding claim comprising a plurality of mass-spring dampers (401a-d) attached to the heatshield (204).
12. The exhaust stackpipe (400) of claim 11, wherein each one of the plurality of massspring dampers (401a-d) is configured to damp a different resonant frequency.
13. A vehicle (100) comprising an exhaust stackpipe (400) according to any preceding claim.
14. The vehicle (100) of claim 13, wherein the exhaust stackpipe (400) is mounted vertically relative to an upright orientation of the vehicle (100).
15. The vehicle (100) of claim 13 or claim 14, wherein the vehicle is an agricultural vehicle and wherein, optionally, the vehicle is an agricultural tractor comprising a cab (106) adjacent the exhaust stackpipe (400).