GB2175641A - Exhaust silencer - Google Patents
Exhaust silencer Download PDFInfo
- Publication number
- GB2175641A GB2175641A GB08513299A GB8513299A GB2175641A GB 2175641 A GB2175641 A GB 2175641A GB 08513299 A GB08513299 A GB 08513299A GB 8513299 A GB8513299 A GB 8513299A GB 2175641 A GB2175641 A GB 2175641A
- Authority
- GB
- United Kingdom
- Prior art keywords
- exhaust silencer
- helical
- inclusive
- helical passage
- baffle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N1/00—Silencing apparatus characterised by method of silencing
- F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
- F01N1/12—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using spirally or helically shaped channels
- F01N1/125—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using spirally or helically shaped channels in combination with sound-absorbing materials
Abstract
An exhaust silencer includes a helical passage 10 whose outer periphery is defined by a foraminous cylindrical shell 11 forming the inner wall of a sound-insulating jacket 12 around the passage 10. A core 19 is open at its upstream end 30.1 and has perforations 30.3 near its downstream end. The axial pitch of a helical baffle 32 defining the helical passage 10 may decrease in the downstream direction. The baffle 32 may be corrugated and may be formed of axially spaced vanes 34, 36, Fig. 7, which may have openings 34.1, 36.1 and may be separated by sound insulating material in cavity 38. <IMAGE>
Description
SPECIFICATION
Exhaust silencer
This invention relates to the silencing of the exhaust of an internal combustion engine. It relates in particular to an exhaust silencer.
According to the invention, a method of silencing the exhaust of an internal combustion engine includes passing the exhaust gases from the engine along a helical passage whose outer periphery is defined by a foraminous cylindrical shell forming the inner wall of a sound-insulating jacket around the passage.
The helical passage may have at least one full turn, and may extend between an inlet chamber and an outlet chamber, the said chambers respectively having inlet and outlet openings which are axially aligned.
The invention extends also to an exhaust silencer, which includes
a core providing a helical passage within a foraminous cylindrical shell; and
an outer sound-insulating jacket around the foraminous cylindrical shell.
The sound-insulating jacket may be provided by a casing around and radially spaced from the foraminous cylindrical shell, and by a sound-insulating material contained in the space between the casing and the shell. The sound-insulating material may be glassfibre, or a material available in the trade under the name INSULWOOL.
The foraminous cylindrical shell may be of metal sheet with perforations.
The casing may be of sheet metal drawn tightly around the sound-insulating material in the space between the casing and the foraminous cylindrical shell, the casing sheet metal having longitudinal edges overlapping and forming a longitudinal seam.
In the silencer there may be provided an inlet chamber at the upstream end of the helical passage, and an outlet chamber at its downstream end. The inlet chamber has an inlet opening and the outlet chamber has an outlet opening, the said inlet and outlet openings being aligned. The inlet chamber may diverge in the downstream direction towards the upstream end of the helical passage.The inlet chamber may be funnel-shaped and may have an axial length which is equal to about half the overall diameter of the helical passage. The outlet chamber may converge in the downstream direction away from the downstream end of the helical passage. The outlet chamber may be funnel-shaped and may have an axial length which is equal to about half the overall diameter of the helical passage.
The core may include a central axial tube and at least one helical baffle arranged wormscrew fashion about the said tube. The axial pitch of the baffle may lie in the range of onehalf diameter to one and a half diameters of the cylindrical shell. The pitch may decrease in a downstream direction. The pitch of the baffle at the downstream end of the core may be about half the pitch at its upstream end.
The baffle may have a wrinkled or undulating surface.
The helical baffle may be provided by a pair of axially spaced vanes defining a helical cavity between them. If desired, sound-insulating material may be provided within the helical cavity. The upstream vane of the pair of axially spaced vanes may be foraminous.
The central axial tube may be open at its upstream end and closed at its downstream end, and may have transverse openings leading transversely out of it in its downstream half. The transverse openings may be arranged in a cluster and may have a total area exceeding the internal cross-sectional area of the tube, say, about three times the said area of the tube. The radial length of the vane may lie within the range of one transverse dimension to two transverse dimensions of the tube.
The internal cross-sectional area of the tube may lie within the range of one-eighth and one and a half times the cross-sectional flow area of the helical passage. Preferably, however, it lies within the range of one-fifth and two-thirds of the cross-sectional flow area of the helical passage.
The axial length of the silencer core may lie within the range of two to five overall diameters of the core.
Various embodiments of the invention will now be described by way of example with reference to the accompanying drawings.
In the drawings,
Figure 1 shows a longitudinal section through one embodiment of the invention;
Figures 2, 3, 4 and 5 show a cross-section as at ll-ll in Fig. 1, of the various stages in the formation of the casing in forming an insulating jacket for the silencer;
Figure 6 shows a longitudinal section through another embodiment of the invention;
Figure 7 shows two other embodiments of the invention, in longitudinal section; and
Figure 8 shows the downstream end of yet another embodiment according to the invention.
Referring to the drawings, a method of silencing the exhaust of an internal combustion engine (not shown), includes passing the exhaust gases from the engine in the direction of arrow 9 along a helical passage 10 whose outer periphery is defined by a foraminous cylindrical shell 11 forming the inner wall of a sound-insulating jacket 12 around the passage 10. The helical passage has at least one full turn and extends between an inlet chamber 14 at its upstream end 10.1 and an outlet chamber 16 at its downstream end 10.2. The inlet chamber has an inlet opening 14.1, and the outlet chamber 16 has an outlet opening 16.1 which is axially aligned with the inlet opening 14.1.
An exhaust silencer in accordance with the invention is referred to generally by reference numeral 18. It includes a core 19 providing the helical passage 10 within the foraminous cylindrical shell 11, and inside the outer sound-insulating jacket 12 around the foramt- nous cylindrical shell 11.
The sound-insulating jacket 12 is provided by a casing 20 around and radially spaced from the foraminous cylindrical shell 11, and by a sound-insulating material 22 in the form of INSULWOOL, contained in the space between the casing 20 and the shell 11.
The foraminous cylindrical shell 11 is of sheet metal and has perforations 24. The casing 20 is of sheet metal drawn tightly around the sound-insulating material 22 in the space between the casing 20 and the foraminous cylindrical shell 11.
The inlet chamber 14 diverges in the downstream direction towards the upstream end 10.1 of the helical passage 10. The inlet chamber 14 is funnel-shaped and has an axial length 14.2 which is equal to about half the overall diameter of the helical passage 10.
The outlet chamber converges in the downstream direction, away from the downstream end 10.2 of the helical passage 10. The outlet chamber 16 is funnel-shaped and has an axial length 16.2 which is equal to about half the overall diameter of the helical passage 10.
The core 19 includes a central axial tube 30 and at least one helical baffle 32 arranged worm-screw fashion about the said tube to define the helical passage 10.
The axial pitch 34 of the baffle 32 may be constant, as seen in Figs. 1, 6 and 7. But it may decrease in a downstream direction, as shown by pitches 34.1 and 34.2 in Fig. 6.
Thus, in Fig. 6, the pitch 34.2 of the baffle at the downstream end 10.2 of the core 19 is about half the pitch 34.1 at its upstream end 10.1. The baffle 32 may have a smooth surface, as shown in Fig. 1. But it may have a wrinkled or undulating surface provided by wrinkles or undulations 32.1 (see Figs. 6, 7 and 8). The uneven surface provided by the wrinkles or undulations to the impinging gases from the exhaust of the engine, will dissipate the pressure energy in the flowing gases.
The helical baffle 32 may be provided by a pair of axially spaced vanes 34 and 36 defining a helical cavity 38 between them (see Fig.
7). Sound-insulating material may be provided within the helical cavity 38. The upstream vane can be foraminous by having openings 34.1. The downstream vane 36 may also have openings 36.1. The radial length 32.2 of the baffle lies within the range of one transverse dimension to two transverse dimensions of the tube 30.
The central axial tube 30 is open at its upstream end 30.1 and closed at its downstream end 30.2, and has transverse openings 30.3 leading transversly out of it in its downstream half. The transverse openings 30.3 are arranged in a cluster and have a total area exceeding the internal cross-sectional area of the tube. The total area of the openings 30.3 may be as much as three times the said area.
The internal cross-sectional area of the tube 30 lies within the range of one-eighth and one and a half times the cross-sectional flow area of the helical passage 10. Preferably, the said cross-sectional area of the tube lies within the range of one-fifth and two-thirds of the crosssectional flow area of the helical passage 10.
The cross-sectional area of the helical passage may be equal to the area of the inlet opening, but is preferably larger. Likewise, the area of the outlet opening is preferably larger than the cross-sectional area of the helical passage.
Referring now to Figs. 2 to 5 of the drawings, there is shown the method in which the outer casing 20 is wrapped tightly around the cylindrical shell 11 with insulating layer 22 around it. In Fig. 2, a partly formed outer casing 20 of sheet metal is shown. It has a partly formed seam 40 having a longitudinal flange 42 overlapped by a hooked formation 44 at the other longitudinal edge of the sheet metal. The hooked formation 44 has limbs 44.1 and 44.2. The casing 20 is then wrapped around the cylindrical shell 11 with a layer of insulating material 22, into the form shown in Fig. 2 of the drawings. At this stage, the layer of insulating material 22 will already have been compressed to some extent.While the seam 40 is in its partly-formed state, as shown in Fig. 2 of the drawings, the limbs 44.1 and 44.2 are folded over onto the flange 42, and pressed tightly together, as shown in Fig. 3 of the drawings. In doing so, the casing 20 is drawn around the periphery of the insulating layer 22 and the cylindrical shell 11. The shell 11 and insulating layer 22 are thereby gripped tightly.
The folding over of the limbs 44.1 and 44.2 onto the flange 42, forms the next stage of the seam 40, as shown in Fig. 3 of the drawings. At this stage, the partly-formed seam 40 may be spot-welded at intervals along its length by means of electrodes 46. The spacing between adjacent spot-welds may be of the order of 25-30 mm. After the partlyformed seam 40 has been spot-welded, it is given an initial bend by gripping in a press brake and bending it so that it lies at an angle, as shown at 47 in Fig. 4, relatively to the outer periphery of the casing 20. The partly-formed seam 40, as shown in Fig. 4, is then further pressed flat by the platens 48, until it lies flat against the periphery, as shown in Fig. 5 of the drawings. The pressing together of the limbs 44.1 and 44.2 and the flange 42, and the final pressing flat of the seam 40, causes the casing 20 to be drawn tightly around the outer periphery of the insu lating layer 22 and shell 11, thereby gripping it firmly frictionally. The same procedure is adopted in wrapping the cylindrical shell 11 around the baffle 32 when making the longitudinal seam 50.
In the embodiment of Fig. 8, a sound-insulation jacket 50 may be provided around the funnel-shaped outlet chamber. The inner wall 52 may be provided with perforations 52.1.
Insulating material 54 is provided in the cavity 56, between the inner wall 52 and the outer wall 58.
Generally, the silencer will be made of mild steel plate and tubing. If a corrosion-resistant silencer is required then it can be made of stainless steel plate and tubing.
Claims (1)
1. A method of silencing the exhaust of an internal combustion engine, which includes passing the exhaust gases from the engine along a helical passage whose outer periphery is defined by a foraminous cylindrical shell forming the inner wall of a sound-insulating jacket around the passage.
2. A method as claimed in Claim 1, in which the helical passage has at least one full turn.
3. A method as claimed in Claim 1 or
Claim 2, in which the helical passage extends between an inlet chamber and an outlet chamber, the said chambers respectively having inlet and outlet openings which are axially aligned.
4. An exhaust silencer, which includes
a core providing a helical passage within a foraminous cylindrical shell: and
an outer sound-insulating jacket around the foraminous cylindrical shell.
5. An exhaust silencer as claimed in Claim 4, in which the sound-insulating jacket is provided by a casing around and radially spaced from the foraminous cylindrical shell, and by a sound-insulating material contained in the space between the casing and the shell.
6. An exhaust silencer as claimed in Claim 4 or Claim 5, in which the foraminous cylindrical shell is of sheet metal with perforations.
7. An exhaust silencer as claimed in Claim 5, in which the casing is of sheet metal drawn tightly around the sound-insulating material in the space between the casing and the foraminous cylindrical shell, the casing sheet metal having longitudinal edges overlapping and forming a longitudinal seam.
8. An exhaust silencer as claimed in any one of Claims 4 to 7 inclusive, in which there is provided an inlet chamber at the upstream end of the helical passage, and an outlet chamber at its downstream end, and in which the inlet chamber has an inlet opening and the outlet chamber has an outlet opening, the inlet and outlet openings being aligned.
9. An exhaust silencer as claimed in Claim 8, in which the inlet chamber diverges in the downstream direction towards the upstream end of the helical passage.
10. An exhaust silencer as claimed in
Claim 9, in which the inlet chamber is funnelshaped and has an axial length which is equal to about half the overall diameter of the helical passage.
11. An exhaust silencer as claimed in any one of Claims 8 to 10 inclusive, in which the outlet chamber converges in the downstream direction away from the downstream end of the helical passage.
12. An exhaust silencer as claimed in
Claim 11, in which the outlet chamber is funnel-shaped and has an axial length which is equal to about half the overall diameter of the helical passage.
13. An exhaust silencer as claimed in any one of Claims 4 to 12 inclusive, in which the core includes a central axial tube, and at least one helical baffle arranged worm-screw fashion about the said tube.
14. An exhaust silencer as claimed in any one of Claims 4 to 13 inclusive, in which the axial pitch of the baffle lies in the range of one-half diameter to one and a half diameters of the cylindrical sheil.
15. An exhaust silencer as claimed in
Claim 13, in which the axial pitch of the baffle decreases in a downstream direction.
16. An exhaust silencer as claimed in
Claim 15, in which the pitch of the baffle at the downstream end of the core is about half the pitch at its upstream end.
17. An exhaust silencer as claimed in any one of Claims 13 to 16 inclusive, in which the baffle has a wrinkled or undulating surface.
18. An exhaust silencer as claimed in any one of Claims 13 to 1 7 inclusive, in which the helical baffle is provided by a pair of axially spaced vanes defining a helical cavity between them.
19. An exhaust silencer as claimed in
Claim 18, in which sound-insulating material is provided within the helical cavity.
20. An exhaust silencer as claimed in
Claim 18 or Claim 19, in which the upstream vane is foraminous.
21. An exhaust silencer as claimed in any one of Claims 13 to 20 inclusive, in which the central axial tube is open at its upstream end and closed at its downstream end, and has transverse openings leading transversely out of it in its downstream half.
21. An exhaust silencer as claimed in
Claim 21, in which the transverse openings are arranged in a cluster and have a total area exceeding the internal cross-sectional area of the tube.
23. An exhaust silencer as claimed in any one of Claims 13 to 22 inclusive, in which the radial length of the baffle lies within the range of one transverse dimension to two transverse dimensions of the tube.
24. An exhaust silencer as claimed in any one of Claims 13 to 23 inclusive, in which the internal cross-sectional area of the tube lies within the range of one-eighth and one and a half times the cross-sectional flow area of the helical passage.
25. An exhaust silencer as claimed in
Claim 24, in which the internal cross-sectional area of the tube lies within the range of onefifth and two-thirds of the cross-sectional flow area of the helical passage.
26. An exhaust silencer as claimed in any one of Claims 4 to 25 inclusive, in which the axial length of the core lies within the range of two to five overall diameters of the core.
27. A novel exhaust silencer, substantially as described and illustrated herein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08513299A GB2175641A (en) | 1985-05-28 | 1985-05-28 | Exhaust silencer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08513299A GB2175641A (en) | 1985-05-28 | 1985-05-28 | Exhaust silencer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8513299D0 GB8513299D0 (en) | 1985-07-03 |
| GB2175641A true GB2175641A (en) | 1986-12-03 |
Family
ID=10579703
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08513299A Withdrawn GB2175641A (en) | 1985-05-28 | 1985-05-28 | Exhaust silencer |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2175641A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104500254A (en) * | 2014-12-11 | 2015-04-08 | 成都育芽科技有限公司 | Dust reduction and noise reduction air passage structure |
| US20170074288A1 (en) * | 2015-09-16 | 2017-03-16 | General Electric Company | Silencer duct having silencing element extending therethrough |
| CN107100706A (en) * | 2017-04-28 | 2017-08-29 | 江苏东泽环保科技有限公司 | New type purification silencer |
| CN111140721A (en) * | 2020-01-17 | 2020-05-12 | 浙江大学 | Spiral noise reduction device and method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115198672B (en) * | 2022-07-05 | 2023-11-24 | 交通运输部公路科学研究所 | Low-frequency noise reduction enhancement type noise elimination device and sound barrier with noise elimination structure |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB358970A (en) * | 1929-11-23 | 1931-10-12 | Zygmunt Wilman | Improvements relating to exhaust silencers |
| GB460148A (en) * | 1934-07-19 | 1937-01-18 | Zygmunt Wilman | Improvements relating to exhaust gas mufflers |
| GB482694A (en) * | 1936-09-07 | 1938-04-04 | Richard Goehler | Improvements relating to silencers for internal combustion engines |
| GB694376A (en) * | 1950-11-10 | 1953-07-22 | Birmingham Small Arms Co Ltd | Improvements in or relating to exhaust silencers |
| GB829012A (en) * | 1955-05-11 | 1960-02-24 | J R Andersson & Co A B | Improvements in or relating to fluid flow mufflers |
| GB1093630A (en) * | 1965-11-23 | 1967-12-06 | Cloyd Daniel Smith | Spiral flow baffle system |
| GB1228582A (en) * | 1967-02-23 | 1971-04-15 | ||
| GB1512297A (en) * | 1975-09-10 | 1978-06-01 | Scovill Manufacturing Co | Silencers |
-
1985
- 1985-05-28 GB GB08513299A patent/GB2175641A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB358970A (en) * | 1929-11-23 | 1931-10-12 | Zygmunt Wilman | Improvements relating to exhaust silencers |
| GB460148A (en) * | 1934-07-19 | 1937-01-18 | Zygmunt Wilman | Improvements relating to exhaust gas mufflers |
| GB482694A (en) * | 1936-09-07 | 1938-04-04 | Richard Goehler | Improvements relating to silencers for internal combustion engines |
| GB694376A (en) * | 1950-11-10 | 1953-07-22 | Birmingham Small Arms Co Ltd | Improvements in or relating to exhaust silencers |
| GB829012A (en) * | 1955-05-11 | 1960-02-24 | J R Andersson & Co A B | Improvements in or relating to fluid flow mufflers |
| GB1093630A (en) * | 1965-11-23 | 1967-12-06 | Cloyd Daniel Smith | Spiral flow baffle system |
| GB1228582A (en) * | 1967-02-23 | 1971-04-15 | ||
| GB1512297A (en) * | 1975-09-10 | 1978-06-01 | Scovill Manufacturing Co | Silencers |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104500254A (en) * | 2014-12-11 | 2015-04-08 | 成都育芽科技有限公司 | Dust reduction and noise reduction air passage structure |
| US20170074288A1 (en) * | 2015-09-16 | 2017-03-16 | General Electric Company | Silencer duct having silencing element extending therethrough |
| CN107100706A (en) * | 2017-04-28 | 2017-08-29 | 江苏东泽环保科技有限公司 | New type purification silencer |
| CN111140721A (en) * | 2020-01-17 | 2020-05-12 | 浙江大学 | Spiral noise reduction device and method thereof |
| CN111140721B (en) * | 2020-01-17 | 2021-01-01 | 浙江大学 | Spiral noise reduction device and method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8513299D0 (en) | 1985-07-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |