CA1127975A - Muffler - Google Patents
MufflerInfo
- Publication number
- CA1127975A CA1127975A CA335,290A CA335290A CA1127975A CA 1127975 A CA1127975 A CA 1127975A CA 335290 A CA335290 A CA 335290A CA 1127975 A CA1127975 A CA 1127975A
- Authority
- CA
- Canada
- Prior art keywords
- muffler
- conduit
- diffusor
- shell
- tube
- 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.)
- Expired
Links
Landscapes
- Exhaust Silencers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a muffler for use in conjunction with an internal combustion engine for reducing the noise level of exhaust gases emitted by the engine, the muffler comprising an elongated diffusor having the shape of a truncated cone, a smaller diameter defining an upstream end of the diffusor and a larger diameter defining a downstream end of the diffusor;
a frustoconically shaped, perforated shell having an upstream, large diameter end coupled to the downstream end of the diffusor and a downstream, smaller diameter end, the shell including perforations; a generally cylindrical conduit having a first end attached to the downstream end of the shell, extending from the shell in a downstream direction, and including an opening adjacent a second end of the conduit; a housing surrounding the shell and the conduit and extending from the diffusor to a discharge end of the muffler; a sound absorbing material disposed between the shell and the housing; a baffle disposed within the housing to seal the opening and an annular space between the conduit and the housing from the discharge end and at least one tube oriented substantially parallel to the conduit, extending past the baffle and having a first, intake end proximate the first end of the conduit and a second, outlet end, communicating with the discharge end so that exhaust gas entering the diffusor can travel through the conduit tube, the opening therein, the annular space and thereafter through the tube to the discharge end of the muffler.
The present invention provides a muffler for use in conjunction with an internal combustion engine for reducing the noise level of exhaust gases emitted by the engine, the muffler comprising an elongated diffusor having the shape of a truncated cone, a smaller diameter defining an upstream end of the diffusor and a larger diameter defining a downstream end of the diffusor;
a frustoconically shaped, perforated shell having an upstream, large diameter end coupled to the downstream end of the diffusor and a downstream, smaller diameter end, the shell including perforations; a generally cylindrical conduit having a first end attached to the downstream end of the shell, extending from the shell in a downstream direction, and including an opening adjacent a second end of the conduit; a housing surrounding the shell and the conduit and extending from the diffusor to a discharge end of the muffler; a sound absorbing material disposed between the shell and the housing; a baffle disposed within the housing to seal the opening and an annular space between the conduit and the housing from the discharge end and at least one tube oriented substantially parallel to the conduit, extending past the baffle and having a first, intake end proximate the first end of the conduit and a second, outlet end, communicating with the discharge end so that exhaust gas entering the diffusor can travel through the conduit tube, the opening therein, the annular space and thereafter through the tube to the discharge end of the muffler.
Description
~.~.27975 The invention refers to a silencer or muffler for internal combustion engines, particularly for two-stroke or cycle internal combustion engines, comprising at its inlet an essentially frustoconical diffuser, a shell of a truncated cone immediately adjoining with its end having the greater diameter the end of the diffusor having the ~reater diameter, and deflecting means for the gas stream dcwnstream of said shell of a truncated cone.
There are already known mufflers for internal combus-tion engines in which the exhaust gases are first passed through a diffusor and in which subsequent to the diffusor insert com-ponents are provided within the muffler housing, said insert components being formed of reflecting elements having, for exam-ple, the shape of perforated reflecting plates, roof-like guide surfaces, choke appertures, frustoconical and perforated hollow bodies having one end closed and/or deflecting means for the gas stream. These known mufflers suffer, however, from substan-tial drawbacks. For instance, manufacture of the insert com-ponents and arranging same within the muffler housing requires a substantial time expenditure, so that the production costs for such known mufflers are very high. ~bove all, the known mufflers are not suitable to attenuate the particularly disturbing high frequencies generated above all when operating two-stroke inter-nal combustion engines.
In known mufflers of an other type, a throttle filter ;is adjoining the diffusor provided at the muffler inlet. Also with such known mufflers the disturbing noise particularly gen-erated when operating two stro~e internal combustlon engines can not be sufficiently attenuated.
It is an o~ect of the present invention to provide a muffler for internal com~ustion engines which is simple in con-struction, inexpensi~e in production and is suitable to give the desired attenuation even of high frequencies. The invention has 112797s as a base a muffler of the type initially described and essen-tially consists in that the shell of the truncated cone forms part of an absorbing filter known per se, is provided with holes and is surrounded by a sound-absorbing material, preferably steel wool, noting that a cylindrical sleeve is adjoining that end of the shell of the truncated cone having the smaller diam-eter and is forming part of the deflecting means. A silencer of such construction does not only allow a space-saving design providing a substantial advantage particularly for motor cycles but does also correspond to the requirements with respect to sound attenuation becoming still more severe in view of the steady progression in the construction of internal combustion engines of steadily increasing power and steadily increasing rotational speed. A further advantage of an inventive muffler resides in that this muffler provides optimal results also with respect to efficiency, so that the fuel consumption can be re-duced particularly for two-stroke internal combustion engines.
Tests have shown that particularly favourable results with respect to sound attenuation and overall efficiency can be obtained if the ratio of the smaller diameter of the diffusor to its greater diameter is within the range of 1:2 to 1:3, par-ticularly 1:2.3, if the ratio of the smaller diameter of the diffusor to the axial length of the diffusor is within the range of 1:8 to 1:12, prefera~ly 1:10, if the ratio of the greater diameter of the absorbing filter to its small dlameter is within the range of 1:0,2~ to 1:0.4, preferably 1:~ 33, and if the ratio of the greater diameter of the absorhing filter to its axial ~ength is within the range o~ 1:2.7 to 1:3, preferably 1:2 85.
Further features of the invention and ad~antages therefrom are set forth in the following description of embodi-ments shown in the drawings.
In the drawings ~igure 1 shows a first embodiment and
There are already known mufflers for internal combus-tion engines in which the exhaust gases are first passed through a diffusor and in which subsequent to the diffusor insert com-ponents are provided within the muffler housing, said insert components being formed of reflecting elements having, for exam-ple, the shape of perforated reflecting plates, roof-like guide surfaces, choke appertures, frustoconical and perforated hollow bodies having one end closed and/or deflecting means for the gas stream. These known mufflers suffer, however, from substan-tial drawbacks. For instance, manufacture of the insert com-ponents and arranging same within the muffler housing requires a substantial time expenditure, so that the production costs for such known mufflers are very high. ~bove all, the known mufflers are not suitable to attenuate the particularly disturbing high frequencies generated above all when operating two-stroke inter-nal combustion engines.
In known mufflers of an other type, a throttle filter ;is adjoining the diffusor provided at the muffler inlet. Also with such known mufflers the disturbing noise particularly gen-erated when operating two stro~e internal combustlon engines can not be sufficiently attenuated.
It is an o~ect of the present invention to provide a muffler for internal com~ustion engines which is simple in con-struction, inexpensi~e in production and is suitable to give the desired attenuation even of high frequencies. The invention has 112797s as a base a muffler of the type initially described and essen-tially consists in that the shell of the truncated cone forms part of an absorbing filter known per se, is provided with holes and is surrounded by a sound-absorbing material, preferably steel wool, noting that a cylindrical sleeve is adjoining that end of the shell of the truncated cone having the smaller diam-eter and is forming part of the deflecting means. A silencer of such construction does not only allow a space-saving design providing a substantial advantage particularly for motor cycles but does also correspond to the requirements with respect to sound attenuation becoming still more severe in view of the steady progression in the construction of internal combustion engines of steadily increasing power and steadily increasing rotational speed. A further advantage of an inventive muffler resides in that this muffler provides optimal results also with respect to efficiency, so that the fuel consumption can be re-duced particularly for two-stroke internal combustion engines.
Tests have shown that particularly favourable results with respect to sound attenuation and overall efficiency can be obtained if the ratio of the smaller diameter of the diffusor to its greater diameter is within the range of 1:2 to 1:3, par-ticularly 1:2.3, if the ratio of the smaller diameter of the diffusor to the axial length of the diffusor is within the range of 1:8 to 1:12, prefera~ly 1:10, if the ratio of the greater diameter of the absorbing filter to its small dlameter is within the range of 1:0,2~ to 1:0.4, preferably 1:~ 33, and if the ratio of the greater diameter of the absorhing filter to its axial ~ength is within the range o~ 1:2.7 to 1:3, preferably 1:2 85.
Further features of the invention and ad~antages therefrom are set forth in the following description of embodi-ments shown in the drawings.
In the drawings ~igure 1 shows a first embodiment and
2 --~27975 Figure 2 shows a second embodiment in section, of a muffler constructed according to the invention.
The muffler according to the invention comprises at its inlet end a diffusor 1 having the shape of a conical tube and belng connected to the exhaust gas conduit of an internal combustion engine with its end 2 having the smaller diameter.
The diffusor 1 is with its end 3 having the greater diameter directly connected to the end 4 of greater diameter of the frus-toconical absorbing filter 5 being surrounded by a muffler housing 6. The shell 7 of the truncated cone is provided with perforations 8 and surrounded by a sound-absorbing material 9, preferably steel wool, being arran~ed within the interior of the muffler housing 6. The end 10 of smaller diameter of the absorbing filter 5 is connected to one end of a tubular sleeve 11, the other end of which is closed by a ~ront wall 12 extending to the muffler housing 6. The front wall 12 is, together with art of the muffler housing 6 and an intermediate wall 13, de-limiting a chamber 14 surrounding the tubular sleeve 11. At that area of the tubular sleeve 11 which is located adjacent the front wall 12, i.e. approximately within the last third of this tubular sleeve, openings 15 are provided through which the exhaust gases can escape from the tubular sleeve 11 into the chamber 14. In view of the chambe~ 14 being closed by the front wall 12, the gases escaping through the openings 15 are ~eflected through an angle of 18~ and are passed to that area of the chamber which is located adjacent the intermediate wall 13 and into which tubes 16, preferably four such t~bes, are opening which e~tend in parallel relation to the tubul.ar sleeve 11 and penetrate through the front wall ~2. The cnds of the tu~es 1~ which are remote from tl~e front wall 12 are sup~orted, for example, by a per~orated inter~ediate wall 17.
~he ~ases flowing i~ backward dircction ~hrough t-he
The muffler according to the invention comprises at its inlet end a diffusor 1 having the shape of a conical tube and belng connected to the exhaust gas conduit of an internal combustion engine with its end 2 having the smaller diameter.
The diffusor 1 is with its end 3 having the greater diameter directly connected to the end 4 of greater diameter of the frus-toconical absorbing filter 5 being surrounded by a muffler housing 6. The shell 7 of the truncated cone is provided with perforations 8 and surrounded by a sound-absorbing material 9, preferably steel wool, being arran~ed within the interior of the muffler housing 6. The end 10 of smaller diameter of the absorbing filter 5 is connected to one end of a tubular sleeve 11, the other end of which is closed by a ~ront wall 12 extending to the muffler housing 6. The front wall 12 is, together with art of the muffler housing 6 and an intermediate wall 13, de-limiting a chamber 14 surrounding the tubular sleeve 11. At that area of the tubular sleeve 11 which is located adjacent the front wall 12, i.e. approximately within the last third of this tubular sleeve, openings 15 are provided through which the exhaust gases can escape from the tubular sleeve 11 into the chamber 14. In view of the chambe~ 14 being closed by the front wall 12, the gases escaping through the openings 15 are ~eflected through an angle of 18~ and are passed to that area of the chamber which is located adjacent the intermediate wall 13 and into which tubes 16, preferably four such t~bes, are opening which e~tend in parallel relation to the tubul.ar sleeve 11 and penetrate through the front wall ~2. The cnds of the tu~es 1~ which are remote from tl~e front wall 12 are sup~orted, for example, by a per~orated inter~ediate wall 17.
~he ~ases flowing i~ backward dircction ~hrough t-he
- 3 ~iz7s7s _hamber 14 flow via tubes 16, which form a flow equalizer, into the chamber 18 and are from there exhausted to atmosphere via exhaust openings 19.
The intermediate wall 13 is preferably formed of per-forated sheet metal. The tubular sleeve 11 can also have a varying diameter instead of a constant diameter.
The ratio of the diameter dl to the diameter Dl of the diffusor 1 is approximately 1:2.3. The ratio of the diameter dl of the diffusor 1 to the axial length ~1 of the diffusor 1 is approximately 1:10. The ratio of the diameter D5 of the ab-sorbing filter 5 to the diameter d5 of the absorbing filter 5 is approximately 1:0.33. The ratio of the diameter D~ of the absorbing filter to the axial length L5 of the absorbing filter is approximately 1:2.85. The axial length Lll of the tubular sleeve 11 is approximately one half of the axial length L5 of the absorbing filter 5. The ratio of the sum of the cross sec-tions of the openings 15 to the cross section of the diffusor 1 at the area of its smallest diameter dl is approximately 0.2:1.
In the embodiment shown in Figure 1, the axis 20 of the diffusor and the axis 21 of the absorbing filter form one single straight line. The embodiment according to Figure 2 dif-fers from the embodiment according to Figure 1 only in that the axis 20 of the diffusor is including with the axis 21 of the absorbing filter an angle ~ which is smaller than lB0 . This provides a space-saving construction.
The intermediate wall 13 is preferably formed of per-forated sheet metal. The tubular sleeve 11 can also have a varying diameter instead of a constant diameter.
The ratio of the diameter dl to the diameter Dl of the diffusor 1 is approximately 1:2.3. The ratio of the diameter dl of the diffusor 1 to the axial length ~1 of the diffusor 1 is approximately 1:10. The ratio of the diameter D5 of the ab-sorbing filter 5 to the diameter d5 of the absorbing filter 5 is approximately 1:0.33. The ratio of the diameter D~ of the absorbing filter to the axial length L5 of the absorbing filter is approximately 1:2.85. The axial length Lll of the tubular sleeve 11 is approximately one half of the axial length L5 of the absorbing filter 5. The ratio of the sum of the cross sec-tions of the openings 15 to the cross section of the diffusor 1 at the area of its smallest diameter dl is approximately 0.2:1.
In the embodiment shown in Figure 1, the axis 20 of the diffusor and the axis 21 of the absorbing filter form one single straight line. The embodiment according to Figure 2 dif-fers from the embodiment according to Figure 1 only in that the axis 20 of the diffusor is including with the axis 21 of the absorbing filter an angle ~ which is smaller than lB0 . This provides a space-saving construction.
Claims (19)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A muffler for use in conjunction with an internal combustion engine for reducing the noise level of exhaust gases emitted by the engine, the muffler comprising an elongated diffusor having the shape of a truncated cone, a smaller diameter defining an upstream end of the diffusor and a larger diameter defining a downstream end of the diffusor; a frustoconically shaped, perforated shell having an upstream, large diameter end coupled to the downstream end of the diffusor and a downstream, smaller diameter end, the shell including perforations; a general-ly cylindrical conduit having a first end attached to the down-stream end of the shell, extending from the shell in a downstream direction, and including an opening adjacent a second end of the conduit; a housing surrounding the shell and the conduit and extending from the diffusor to a discharge end of the muffler; a sound absorbing material disposed between the shell and the housing; a baffle disposed within the housing to seal the opening and an annular space between the conduit and the housing from the discharge end and at least one tube oriented substantially paral-lel to the conduit, extending past the baffle and having a first, intake end proximate the first end of the conduit and a second, outlet end, communicating with the discharge end so that exhaust gas entering the diffusor can travel through the conduit tube, the opening therein, the annular space and thereafter through the tube to the discharge end of the muffler.
2. A muffler as claimed in claim 1 in which the ratio between the smaller diameter of the diffusor and its larger diameter is in the range of 1:2 to 1:3.
3. A muffler according to claim 2, wherein said ratio is 1:2.3.
4. A muffler as claimed in claim 2, in which the ratio between the smaller diameter of the diffusor and the axial length of the diffusor is in the range of 1:8 to 1:12.
5. A muffler as claimed in claim 4, wherein the last mentioned ratio is 1:10.
6. A muffler as claimed in claim 1, in which the ratio between the larger diameter of the shell and its smaller diameter is in the range of 1:0.25 to 1:0.4.
7. A muffler as claimed in claim 6, wherein the last mentioned ratio is 1:0.33.
8. A muffler as claimed in claim 1, in which the ratio between the larger diameter of the shell and its axial length is in the range of 1:2.7 to 1:3.
9. A muffler as claimed in claim 8, wherein the last mentioned ratio is 1:2.85.
10. A muffler as claimed in claim 1, in which the axial length of the conduit is approximately one half of the axial length of the shell.
11. A muffler as claimed in claim 6, in which the second end of the conduit is closed, and wherein the opening of the conduit comprises a plurality of holes extending generally radially through the conduit and located in a portion of the conduit extending over about one third of its axial length from the second end of the conduit.
12. A muffler according to claim 11, wherein the baffle is defined by a plate extending transversely across the housing, the plate being positioned and arranged to close the second, downstream end of the conduit.
13. A muffler according to claim 12, including an intermediate plate spaced from the first mentioned plate and disposed proximate the first end of the conduit, and wherein the tube is supported by the plates.
14. A muffler according to claim 13, wherein the second tubes extend over a major portion of the length of the annular space, and wherein the intermediate plate includes perforations to permit the passage of exhaust gases from the radial openings in the first tube to an upstream end of the second tube.
15. A muffler according to claim 12, wherein the second tubes extend over a major portion of the length of the annular space.
16. A muffler as claimed in claim 11, in which the ratio between the sum of the cross sections of the holes and the cross section of the diffusor at its smaller diameter is in the range of 0.15:1 and 0.25:1.
17. A muffler according to claim 16, wherein the last mentioned ratio is 0.2:1.
18. A muffler according to claim 17, in which the length of said tube is at least one third of the axial length of the diffusor.
19. A muffler as claimed in claim 1, in which the axis of the diffusor is inclined relative to the axis of the shell by an angle of less than 180°.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA335,290A CA1127975A (en) | 1979-09-07 | 1979-09-07 | Muffler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA335,290A CA1127975A (en) | 1979-09-07 | 1979-09-07 | Muffler |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1127975A true CA1127975A (en) | 1982-07-20 |
Family
ID=4115111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA335,290A Expired CA1127975A (en) | 1979-09-07 | 1979-09-07 | Muffler |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1127975A (en) |
-
1979
- 1979-09-07 CA CA335,290A patent/CA1127975A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |