JP2014196676A - Muffler of internal combustion engine - Google Patents

Abstract

To control the flow of exhaust flow and to ensure a silencing effect with a simple structure. A separator 30 divides the inside of a body cylinder portion 26 of a silencer into a first chamber 31 located upstream of exhaust and a second chamber 32 located downstream of exhaust. A separator forming punching hole 35 is formed in a portion of the separator 30 where the exhaust does not directly hit along the direction of the opening 21 </ b> A that is the downstream end opening of the exhaust pipe 14. [Selection] Figure 3

Description

  The present invention relates to a silencer for an internal combustion engine.

  In the silencer of the internal combustion engine, the silencer is partitioned into a plurality of expansion chambers by a separator, and a plurality of communication cylinders straddling the plurality of expansion chambers are provided so that the exhaust reaches the most downstream expansion chamber via the communication cylinders. 2. Description of the Related Art Conventionally, a configuration in which a tail pipe passes through a separator and is opened in the most downstream expansion chamber, and is opened outside and exhaust is discharged from the tail pipe to the outside (see Patent Document 1).

JP 2004-270572 A

  In the conventional silencer according to Patent Document 1, the exhaust gas flowing in from the exhaust pipe repeatedly expands and compresses in the expansion chamber, thereby obtaining a silencing effect. The structure was complicated and the structure was complicated. In addition, in the silencer disclosed in Patent Document 1, four expansion chambers are formed. However, many other conventional silencers of this type have a relatively large number of expansion chambers and many complicated structures. . For this reason, conventionally, it has been desired to make the structure as simple as possible while ensuring the silencing effect.

  Here, many of the conventional exhaust pipes including the conventional silencer according to Patent Document 1 described above do not have a special effect on the flow of exhaust to improve the silencing effect, and the silencing is performed efficiently. There are few things.

  Therefore, an object of the present invention is to provide a silencer for an internal combustion engine that can secure a silencing effect with a simple structure by controlling the flow of exhaust flow.

  As a means for solving the above-mentioned problems, the invention described in claim 1 includes a cylindrical tubular body (26), a disk-shaped separator (30) that is a partition partitioning the inside of the tubular body (26), and the tubular body. And a tail pipe (28) extending from the inside of the body (26) to the outside, connected to an exhaust pipe (14) for discharging exhaust from the internal combustion engine (4), and allowed to flow into the cylinder (26) The silencer of the internal combustion engine exhausts exhaust gas to the outside from the tail pipe (28), and the separator (30) exhausts the inside of the cylindrical body (26) in the axial direction of the cylindrical body (26). The first chamber (31) located on the upstream side of the exhaust gas and the second chamber (32) located on the downstream side of the exhaust gas are partitioned into the tail pipe (28) from the second chamber (32) side to the separator ( 30), one end is disposed in the first chamber (31) and the other end is A plurality of tail pipe forming punching holes (33) are formed on an outer peripheral surface of a portion that is arranged outside the silencer, closes the one end, and is located in the second chamber (32), A plurality of separator forming punching holes (35) are formed in a portion of the separator (30) where the exhaust does not directly hit along the direction of the downstream end opening (21A) of the exhaust pipe (14). It is characterized by that.

  According to a second aspect of the present invention, a through hole (30A) through which the tail pipe (28) passes is formed at the center of the separator (30), and the tail pipe (28) is formed through the through hole (30A). It is formed in a smaller diameter, and the other end portion side is welded and fixed to the cylindrical body (26).

  According to a third aspect of the present invention, the portion of the separator (30) that is directly exposed to the exhaust gas along the direction of the downstream end opening (21A) is the through hole (30A) in the separator (30). ) Is set in a region located outside in the radial direction.

  According to a fourth aspect of the present invention, when the vehicle is mounted, the vehicle is arranged so as to be offset along one side in the vehicle width direction with respect to the center in the vehicle width direction and extend along the front-rear direction. Of the two semicircular regions of the partitioned separator (30), in the semicircular region located on the inner side in the vehicle width direction, in the directing direction of the downstream end opening (21A) of the separator (30) A portion where the exhaust directly hits along is set.

The invention according to claim 5 is characterized in that the cylindrical body (26) is a single tube forming a silencer outer shape.
According to a sixth aspect of the present invention, the separator forming punching hole (35) in the separator (30) is larger than the tail pipe forming punching hole (33) in the tail pipe (28), and the separator forming punching is performed. The opening area of the hole (35) is substantially equal to the opening area of the tail pipe forming punching hole (33).
The invention described in claim 7 is characterized in that an opening area of the tail pipe forming punching hole (33) is larger than a cross-sectional area of an internal space of the tail pipe (28).

  In the first aspect of the invention, the exhaust gas greatly expands in the first chamber so that it bounces off at the portion of the separator where the punching hole is not formed, and then enters the second chamber through the separator. The flow of the exhaust gas is controlled so as to reach the punching hole on the surface, and the flow path length and the expansion volume of the exhaust gas are ensured, so that the silencing is effectively performed, and the silencing effect can be secured even though the structure is simple. Further, since the exhaust does not directly hit the inner peripheral surface of the cylinder, it is possible to prevent discoloration from occurring in the cylinder.

  In the invention according to claim 2, a gap is formed between the tail pipe and the separator, and the tail pipe and the separator can be prevented from being deformed and interfered by thermal expansion.

  In the third aspect of the present invention, the exhaust hitting the gap formed between the tail pipe and the separator can be reduced, and the exhaust can be suitably expanded in the first chamber.

  According to the fourth aspect of the present invention, the high temperature portion is located on the inner side in the vehicle width direction. Therefore, even if discoloration occurs in the cylindrical body, it becomes inconspicuous and the appearance can be suitably maintained.

In the invention according to claim 5, even if the cylindrical body forming the expansion chamber is a single pipe constituting the outer shape of the exhaust pipe, a sufficient silencing effect can be obtained. Can be achieved.
In the invention described in claim 6, it is possible to ensure a silencing effect while improving exhaust passage.
According to the seventh aspect of the present invention, exhaust passage can be improved.

1 is a right side view of a motorcycle equipped with a silencer according to an embodiment of the present invention. It is a right view of an exhaust pipe and the said silencer connected to this. It is a front view of the exhaust pipe and the silencer. It is a top view of the exhaust pipe and the silencer. It is the figure which looked at the said exhaust pipe and the said silencer along the arrow B direction of FIG. It is sectional drawing which follows the AA line of FIG. It is sectional drawing of the silencer along the direction orthogonal to the axial direction of the tail pipe provided in the said silencer. It is sectional drawing explaining the silencer which concerns on the modification of the said embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used for the following description, the arrow FR indicates the front of the vehicle, and the arrow UP indicates the upper side of the vehicle.

  FIG. 1 is a right side view of a main part of a motorcycle 1 equipped with an exhaust pipe of a saddle-ride type vehicle according to the present embodiment. In the motorcycle 1, an internal combustion engine 4 is disposed between a front wheel 2 and a rear wheel 3, and the internal combustion engine 4 is a cylinder portion 6 erected upward from an upper front side of the crankcase 5 and the crankcase 5. And.

  The body frame 7 of the motorcycle 1 includes a head pipe 8 located at the front end, a main frame 9 extending rearward from the head pipe 8, and extending downward from the head pipe 8, and a down frame 10 extending downward from the head pipe 8. . In the internal combustion engine 4, the rear portion of the crankcase 5 is supported by a pivot plate 11 provided at the lower end portion of the main frame 9, and the front portion of the crankcase 5 is supported by the lower end portion of the down frame 10.

  A swing arm 12 extending rearward is supported on the pivot plate 11. The swing arm 12 is supported by the pivot plate 11 so that the front end of the swing arm 12 can swing in the vertical direction, and the rear wheel 3 at the rear of the swing arm 12 can swing.

  An intake system member 13 is connected to the rear part of the cylinder part 6, and an exhaust pipe 14 is connected to the front part of the cylinder part 6. Specifically, the cylinder portion 6 includes a cylinder block that is directly coupled to the crankcase 5, a cylinder head that is coupled to the cylinder block and in which a combustion chamber and the like are formed, and a head cover that covers the cylinder head. The intake system member 13 and the exhaust pipe 14 are coupled to the cylinder head of the cylinder portion 6 and can communicate with the combustion chamber.

  In a side view, the exhaust pipe 14 extends from the front portion of the cylinder portion 6 obliquely downward to the front, then curves obliquely downward to the rear, and extends substantially straight rearward below the crankcase 5. Further, the exhaust pipe 14 changes its angle at a position on the outer side in the vehicle width direction of the front end of the rear wheel 3 and is bent obliquely rearward and upward, and a silencer 15 is connected to the rear end thereof. The silencer 15 extends obliquely rearward and upward from the rear end portion of the exhaust pipe 14 and is located on the outer side in the vehicle width direction of the rear wheel 3. That is, when mounted on the vehicle, the silencer 15 is arranged offset to one side in the vehicle width direction with respect to the center in the vehicle width direction. The exhaust pipe 14 and the silencer 15 constitute an exhaust device Ex for the motorcycle 1.

  The exhaust pipe 14 is welded to the bracket 16 protruding upward on the outer peripheral portion of the portion extending in the front-rear direction below the crankcase 5, and the upper portion of the bracket 16 is fixed to the lower portion of the pivot plate 11, thereby It is supported by. A catalyst 50 is housed inside a portion of the exhaust pipe 14 that extends in the front-rear direction below the crankcase 5.

  Further, the silencer 15 is welded with a bracket 17 at a position substantially in the center in the front-rear direction, and the upper portion of the bracket 17 is fixed and supported at an appropriate position of the vehicle body frame 7.

  FIG. 2 is a right side view of only the exhaust pipe 14 and the silencer 15, and the orientation of the exhaust pipe 14 and the silencer 15 in the figure is in a state when mounted on a vehicle (note that the figure used in the description below) 3 and FIG. 4 are also states when the vehicle is mounted).

  The exhaust pipe 14 includes a connecting portion 20 with the cylinder portion 6, an inner tube 21 indicated by a broken line in the drawing extending from the connecting portion 20, and an outer tube 22 extending from the connecting portion 20 and covering the inner tube 21 from the outside. It has a double tube structure. The catalyst 50 is provided in the middle of the inner pipe 21. Further, in the present embodiment, the outer tube 22 has a shape that expands in front of the accommodating portion of the catalyst 50, but it does not have to be such a shape.

  The exhaust gas flows from the cylinder part 6 through the connecting part 20 and the inner pipe 21 to the silencer 15 and is discharged from the silencer 15. Hereinafter, in the exhaust pipe 14, in the exhaust flow direction, the connecting portion 20 side may be referred to as an upstream side, and the silencer 15 side may be referred to as a downstream side. In the silencer 15, the exhaust inflow side may be referred to as the upstream side, and the exhaust side may be referred to as the downstream side.

  In the present embodiment, the inner tube 21 and the outer tube 22 are formed of a pipe material having a circular cross section, and the downstream side end portion of the outer tube 22 indicated by reference numeral 22E in the drawing and the downstream side of the inner tube 21 indicated by reference numeral 21E. As referred to by the end portion, the inner tube 21 extends rearward longer than the outer tube 22.

  Referring also to FIGS. 3 and 4, a cylindrical joint tube 23 is fixed to the inner peripheral surface of the downstream end portion 22 </ b> E that is the rear end portion of the outer tube 22. It protrudes rearward (downstream) from the downstream end 22E of the outer tube 22.

A through hole 23A (see FIGS. 2 and 3) through which the inner tube 21 passes is formed in the central region of the joint tube 23, and a portion of the inner tube 21 that passes through the through hole 23A hits the through hole 23A over the entire circumference. It touches.
3 and 4, in this embodiment, the downstream portion of the inner tube 21 and the outer tube 22 extends outward in the vehicle width direction as it extends rearward, and as shown in FIG. 2 in a side view. The downstream portion of the inner tube 21 and the outer tube 22 extends obliquely rearward and upward.

  The silencer 15 is connected to the exhaust pipe 14 by fitting a cylindrical connecting tube portion 24 located at the front end portion (upstream end portion) to the outer peripheral surface of the joint tube 23 and performing welding or the like. Has been. The downstream end portion 21 </ b> E of the inner pipe 21 is located and opened inside the connecting cylinder portion 24, and communicates with the silencer 15. It should be noted that such a mode of connection between the silencer 15 and the exhaust pipe 14 may be any known means such as clamping with a clamp.

The silencer 15 includes the connecting tube portion 24 that extends coaxially with the portion on the outer peripheral side of the portion that extends downstream from the portion that penetrates the through hole 23A in the inner tube 21, and the rear end portion of the connecting tube portion 24 ( From the downstream end portion, the introduction cylinder extends outward in the vehicle width direction as it extends rearward (see FIGS. 3 and 4), extends obliquely rearward and upward in a side view (see FIG. 2), and increases in diameter toward the downstream side. Portion 25, a cylindrical main body tube portion 26 that is bent inward in the vehicle width direction from the rear end portion (downstream end portion) of the introduction tube portion 25 and extends substantially straight in the front-rear direction, and the rear of the main body tube portion 26 A disc-shaped end cap 27 that closes the end portion (downstream end portion), and a cylindrical tail that has one end portion disposed in the silencer 15 and the other end portion protruding from the end cap 27 to the outside. And a pipe 28. The tail pipe 28 extends along the axial direction of the main body cylinder portion 26.
The connecting cylinder part 24 is connected to the exhaust pipe 14 in a state along the central axis of the downstream end 21E of the inner pipe 21. The main body cylinder portion 26 extends in a direction different from the central axis lines of the connection cylinder portion 24 and the introduction cylinder portion 25 and bends with respect to the connection cylinder portion 24 and the introduction cylinder portion 25 along the center axis line. Thus, the central axis of the connecting cylinder part 24 enters the main body cylinder part 26 from the inside of the upstream opening of the main body cylinder part 26 and extends rearward.

  With reference to FIGS. 5 to 7, in the present embodiment, the main body cylinder portion 26 includes a cylindrical inner cylinder 26 </ b> A and a cylindrical outer cylinder 26 </ b> B that covers the outer side of the inner cylinder 26 </ b> A. The front end portion (upstream end portion) of 26A is connected to the introduction tube portion 25, and the rear end portion (downstream end portion) of the inner tube 26A is closed by the end cap 27. Further, the outer cylinder 26 </ b> B forms the outer shape of the silencer 15 across the outer peripheral surface of the introduction cylinder portion 25 and the end cap 27.

  Here, a single disc-shaped separator 30 is disposed in the inner cylinder 26A, and this separator 30 is located in the inner cylinder 26A in the axial direction of the inner cylinder 26A and on the upstream side of the exhaust. The chamber is divided into two expansion chambers: a first chamber 31 and a second chamber 32 located on the downstream side of the exhaust.

  The above-described tail pipe 28 penetrates the separator 30 from the second chamber 32 side, and has one end portion disposed in the first chamber 31 and the other end portion disposed outside the silencer 15, and the one end portion at the one end portion. The plug 28B is inserted and closed. Further, as shown in FIG. 6, a plurality of tail pipe forming punching holes 33 are formed on the outer peripheral surface of the portion located in the second chamber 32 of the tail pipe 28.

  The tail pipe 28 passes through a through hole 30A formed in the central portion of the separator 30. The tail pipe 28 is formed to have a smaller diameter than the through hole 30A, and between the outer peripheral surface of the tail pipe 28 and the through hole 30A. A gap is formed in. The tail pipe 28 passes through a through hole 28A formed at the center of the end cap 27 and is welded to the inner peripheral surface of the through hole 28A, so that the tail pipe 28 is indirectly fixed to the main body cylinder portion 26.

  Further, of the portions of the tail pipe 28 located in the second chamber 32, the portion located on the end cap 27 side covers the entire outer circumferential surface of the portion located on the end cap 27 side, A cylindrical covering cylinder 34 that forms a closed space is welded.

  In the present embodiment, the tail pipe forming punching hole 33 is formed with a predetermined density over the entire region of the tail pipe 28 located in the second chamber 32, but is located in the second chamber 32 of the tail pipe 28. Of the portions, the portion covered with the covering cylinder 34 located on the end cap 27 side has a lower density of forming the tail pipe forming punching holes 33 than the portion not covered with the covering tube 34. In this embodiment, by providing the covering cylinder 34, a part of the exhaust can flow into a closed space formed by the covering cylinder 34 and the tail pipe 28.

  3 to 5 and FIG. 7, in the present embodiment, the silencer 15 is a surface in which the opening 21 </ b> A of the downstream end 21 </ b> E of the inner pipe 21 of the exhaust pipe 14 faces the first chamber 31 side in the separator 30. It is connected to the exhaust pipe 14 so as to be oriented. Specifically, the central axis L1 of the linearly extending portion including the downstream end portion 21E located on the downstream side in the inner tube 21 is directed to the surface facing the first chamber 31 side in the separator 30, and from the opening 21A. The exhaust gas flowing into the first chamber 31 hits the surface of the separator 30 facing the first chamber 31 side along the central axis L1.

More specifically, in FIGS. 3 to 5 and FIG. 7, the symbol P <b> 1 indicates an intersection where the central axis L <b> 1 intersects the surface of the separator 30 facing the first chamber 31, and flows into the first chamber 31 from the opening 21 </ b> A. The exhaust gas flows so as to hit the intersection P1.
Referring to FIG. 7, the intersection point P1 is a region radially outside the center point C1 of the separator 30 and is in a region radially outside the through hole 30A. In the following, the direction of the opening 21A refers to a direction extending toward the separator 30 along the central axis L1.

  In the present embodiment, as shown in FIG. 7, a plurality of separator forming punching holes 35 for allowing the exhaust gas to flow from the first chamber 31 to the second chamber 32 are formed in the separator 30. The separator forming punching hole 35 is not formed at the intersection P1 of the separator 30 where the exhaust directly hits along the directing direction of the opening 21A, and the portion where the exhaust does not hit directly along the directing direction of the opening 21A. Is formed.

  Specifically, in the present embodiment, the two semicircular regions 40A and 40B in the separator 30 partitioned by the straight line L2 orthogonal to the straight line connecting the intersection point P1 and the central point C1 of the separator 30 and passing through the central point C1. The separator forming punching hole 35 is not formed in the semicircular region 40A where the intersection point P1 is located, and the separator forming punching hole 35 is formed at a predetermined density over most of the other semicircular region 40B.

In the present embodiment, the straight line L2 extends substantially along the vertical direction, and the semicircular area 40A is located on the outer side in the vehicle width direction than the semicircular area 40B. The intersection point P <b> 1 is located in the vicinity of the outer end portion of the separator 30 in the vehicle width direction.
In this embodiment, the separator forming punching hole 35 in the separator 30 is larger than the tail pipe forming punching hole 33 in the tail pipe 28. That is, the diameter of the separator forming punching hole 35 is larger than the diameter of the tail pipe forming punching hole 33. On the other hand, the opening area of the separator forming punching hole 35 is substantially equal to the opening area of the tail pipe forming punching hole 33 exposed to the second chamber 32 (not covered by the covering cylinder 34). That is, the sum of the opening areas of the plurality of separator forming punching holes 35 is substantially equal to the sum of the opening areas of the plurality of tail pipe forming punching holes 33 exposed to the second chamber 32. In addition, the aspect of such a diameter and opening area is a preferable aspect, and is not limited to this.
Further, in the present embodiment, the tail pipe forming punching hole 33 exposed to the second chamber 32 (not covered by the covering cylinder 34) is exposed rather than the cross sectional area of the internal space of the tail pipe 28 (the cross sectional area of the circular portion forming the passage). The opening area of is larger. That is, the sum of the opening areas of the plurality of tail pipe forming punching holes 33 that are exposed to the second chamber 32 is larger than the cross-sectional area of the internal space of the tail pipe 28.
Note that the relationship between the cross-sectional area of the internal space in the tail pipe 28 and the opening area of the tail pipe forming punching hole 33 is also a preferable aspect, and is not limited thereto.

As described above, the silencer 15 according to the present embodiment includes the main body cylinder portion 26 that is a cylindrical cylinder, the disk-shaped separator 30 that is a partition wall that partitions the main body cylinder portion 26, and the inside of the main body cylinder portion 26. And a tail pipe 28 extending from the outside to the outside, connected to the exhaust pipe 14 for discharging the exhaust from the internal combustion engine 4, and exhausted into the main body cylinder portion 26 is discharged from the tail pipe 28 to the outside.
In the silencer 15, the separator 30 is disposed in the main body cylinder portion 26 in the axial direction of the main body cylinder portion 26. The first chamber 31 is located upstream of the exhaust, and the second chamber 31 is located downstream of the exhaust. The tail pipe 28 penetrates through the separator 30 from the second chamber 32 side, one end portion is disposed in the first chamber 31 and the other end portion of the silencer. A plurality of tail pipe forming punching holes 33 are formed on the outer peripheral surface of a portion that is arranged outside, closes the one end, and is located in the second chamber 32.
Further, in the silencer 15 of the present embodiment, a plurality of separator forming punching holes 35 are formed in a portion where the exhaust does not directly hit along the directing direction of the opening 21 </ b> A which is the downstream end opening of the exhaust pipe 14. .

  In such a silencer 15, the exhaust gas greatly expands in the first chamber 31 so as to bounce off the portion of the separator 30 where the separator forming punching hole 35 is not formed, and then enters the second chamber 32 through the separator 30. Thereafter, the flow of the exhaust gas is controlled so as to reach the tail pipe forming punching hole 33 on the outer peripheral surface of the tail pipe 28, and the flow path length and the expansion volume of the exhaust gas are secured, so that silencing is effectively performed. While having a simple structure, it is possible to ensure a silencing effect. Further, since the exhaust does not directly hit the inner peripheral surface of the main body cylinder portion 26, it is possible to prevent discoloration from occurring in the main body cylinder portion 26.

Further, in the silencer 15 of the present embodiment, a through hole 30A through which the tail pipe 28 penetrates is formed at the center of the separator 30, the tail pipe 28 is formed with a smaller diameter than the through hole 30A, and the tail pipe 28 is exposed to the outside. The exposed other end side is welded and fixed to the main body cylinder portion 26 via the end cap 27.
In this configuration, a gap is formed between the tail pipe 28 and the separator 30, and the tail pipe 28 and the separator 30 can be prevented from being deformed and interfered by thermal expansion.

Further, in the silencer 15 of the present embodiment, the portion of the separator 30 that is directly exposed to the exhaust is set in a region located on the outer side in the radial direction than the through hole 30A in the separator 30.
In this configuration, the exhaust that impinges on the gap formed between the tail pipe 28 and the separator 30 can be reduced, and the exhaust can be suitably expanded in the first chamber 31.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the present invention is mounted on the motorcycle 1, but the vehicle is not limited to a motorcycle but may be a tricycle or a four-wheel vehicle. The engine is not limited to a single cylinder engine, and may be connected to an exhaust pipe extending from a multi-cylinder engine.

  Further, in the above-described embodiment, the main body cylinder portion 26 has a double pipe structure including the inner cylinder 26A and the outer cylinder 26B. However, as shown in FIG. 8, the main body cylinder portion 26 includes only the inner cylinder 26A. It is good also as a structure. With the configuration according to the present invention, the flow of exhaust gas is controlled and the flow path length and expansion volume of the exhaust gas are ensured, so that silencing is effectively performed. A silencing effect is obtained. For this reason, even if it is a single tube structure like this modification, it can mute suitably, In this case, productivity and weight reduction can be achieved.

  Further, in the present embodiment, the straight line L2 described above extends substantially along the vertical direction, the semicircular region 40A is located on the outer side in the vehicle width direction than the semicircular region 40B, and the intersection P1 is at the separator 30. Although the structure located in the vicinity of the vehicle width direction outer end portion has been described, the silencer is changed after changing the shape of the exhaust pipe so that the intersection P1 is located in the semicircular region 40B located on the vehicle width direction inner side. You may connect. In this case, in the silencer, the high temperature portion is located on the inner side in the vehicle width direction, so that even if discoloration occurs in the main body cylindrical portion 26 that is a cylindrical body, the appearance can be suitably maintained.

1 Motorcycle (saddle-ride type vehicle)
4 Internal combustion engine 14 Exhaust pipe 21A Opening (downstream end opening)
26 Body cylinder (cylinder)
28 Tail pipe 30 Separator 30A Through hole 31 First chamber 32 Second chamber 33 Tail pipe forming punching hole 35 Separator forming punching hole

Claims (7)

A cylindrical tube (26);
A disc-shaped separator (30) which is a partition wall for partitioning the inside of the cylindrical body (26);
A tail pipe (28) extending from the inside of the cylindrical body (26) to the outside,
A silencer for an internal combustion engine that is connected to an exhaust pipe (14) that exhausts exhaust from the internal combustion engine (4) and that exhausts the exhaust that has flowed into the cylindrical body (26) to the outside through the tail pipe (28). And
The separator (30) includes a first chamber (31) positioned upstream of the exhaust in the axial direction of the cylinder (26) and a first chamber (31) positioned downstream of the exhaust. Divided into two rooms (32),
The tail pipe (28) penetrates the separator (30) from the second chamber (32) side, and has one end portion disposed in the first chamber (31) and the other end portion outside the silencer. A silencer for an internal combustion engine in which a plurality of tail pipe forming punching holes (33) are formed in an outer peripheral surface of a portion located in the second chamber (32) and closed at the one end. ,
A plurality of separator forming punching holes (35) are formed in a portion of the separator (30) where the exhaust does not directly hit along the direction of the downstream end opening (21A) of the exhaust pipe (14). A muffler for an internal combustion engine. A through hole (30A) through which the tail pipe (28) passes is formed at the center of the separator (30),
The said tail pipe (28) is formed in a diameter smaller than the said through-hole (30A), The said other end part side is welded and fixed to the said cylinder (26), The fixed body of Claim 1 characterized by the above-mentioned. A silencer for internal combustion engines.   A portion of the separator (30) that is directly exposed to the exhaust gas along the direction of the downstream end opening (21A) is radially outward from the through hole (30A) in the separator (30). The muffler for an internal combustion engine according to claim 2, wherein the silencer is set in a region where it is located. At the time of vehicle mounting, it is arranged to extend along the front-rear direction offset to one side in the vehicle width direction relative to the center in the vehicle width direction,
The downstream end of the separator (30) is disposed in a semicircular region located on the inner side in the vehicle width direction of two semicircular regions of the separator (30) partitioned by a straight line extending in the vertical direction when viewed from the front. The silencer for an internal combustion engine according to claim 3, characterized in that a portion to which exhaust directly hits is set along the directivity direction of the portion opening (21A).   The silencer for an internal combustion engine according to any one of claims 1 to 4, wherein the cylindrical body (26) is a single pipe that forms a silencer outer shape.   The separator forming punching hole (35) in the separator (30) is larger than the tail pipe forming punching hole (33) in the tail pipe (28), and the opening area of the separator forming punching hole (35) is: 6. The silencer for an internal combustion engine according to claim 1, wherein the silencer is substantially equal to an opening area of the tail pipe forming punching hole (33).   The internal combustion engine according to any one of claims 1 to 6, wherein an opening area of the tail pipe forming punching hole (33) is larger than a cross-sectional area of an internal space of the tail pipe (28). Silencer.

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