JP6296126B2 - Engine exhaust silencer - Google Patents

Description

  The present invention relates to an exhaust silencer mounted on a vehicle equipped with an engine.

  Vehicles such as automobiles are provided with an exhaust silencer (muffler) in order to reduce engine exhaust noise. Generally, an exhaust silencer includes a silencer body that forms a silence space (expansion chamber), and an exhaust pipe that forms an exhaust path through which the exhaust passes in the silence space. The exhaust pipe includes an exhaust introduction pipe that introduces engine exhaust into the silencing space, and an exhaust outlet pipe that discharges the exhaust from the silencing space to the outside.

  As one of the measures to reduce the exhaust noise (air flow noise), a number of small holes are drilled in the pipe wall of the exhaust pipe arranged in the silencer body, and the outer periphery of the drilled portion of the small hole group is made of glass wool or the like. A structure covered with a sound absorbing material is known (for example, Patent Document 1). As a result, the airflow sound is released outside the pipe through the small hole and is absorbed by the sound absorbing material.

JP 2004-150310 A

  In order to face the sound absorbing material around the exhaust pipe, it is necessary to secure a corresponding space around the exhaust pipe. Usually, since the size of the silencer body is required to be as small as possible, there may be a case where the exhaust pipe must be disposed close to the wall portion of the silencer body. In this case, the sound absorbing material is inserted into a narrow space, which increases the difficulty in production technology, and causes a problem that the sound absorbing material cover that covers the sound absorbing material contacts the wall portion of the silencer body. In particular, when the exhaust pipe is meandered using a U-shaped curved pipe in order to increase the length of the exhaust pipe in the silencer body, the above problem becomes significant.

  An object of the present invention is to provide an engine exhaust in which a sound absorbing material can be arranged as much as possible on the outer periphery of the exhaust pipe even when there is a restriction that the wall portion of the silencer body and the exhaust pipe must be arranged adjacent to each other. The object is to provide a silencer.

  An engine exhaust silencer according to an aspect of the present invention includes a silencer body that forms a silencer space into which exhaust of a vehicle engine is introduced, and an exhaust path through which the exhaust passes in the silencer space. An exhaust pipe including a first straight pipe and a second straight pipe extending substantially in parallel, a first sound-absorbing material arranged on the outer circumference of the first straight pipe, and a second arranged on the outer circumference of the second straight pipe A silencer body, the silencer body includes a linearly extending wall section defining the silencing space, and the first and second straight pipes are first and second bored in the pipe wall, respectively. Two small hole groups, the first straight tube is disposed adjacent to the wall portion, while the second straight tube is disposed away from the wall portion, the second small hole group, A predetermined region in the tube axis direction of the second straight tube is perforated over the entire circumference of the tube wall. Both the second sound absorbing material is disposed on the outer periphery of the second straight tube so as to cover the entire circumference of the tube wall, and the first small hole group is formed in a predetermined region in the tube axis direction of the first straight tube. The first straight pipe is formed on the outer circumference of the first straight pipe so as to cover the pipe wall portion, and is perforated only in the pipe wall portion substantially opposite to the second straight pipe. Is arranged.

  According to this exhaust silencer, since the exhaust pipe includes the first and second straight pipes, the length of the exhaust pipe in the silence space can be increased. Thereby, the reduction degree of the exhaust noise in exhaust pipe itself can be raised. In addition, the silencing effect is enhanced by applying the first and second sound absorbing materials to the first and second straight tubes. That is, about the 2nd straight pipe arrange | positioned spaced apart from the wall part of a silencer main body, the 2nd small hole group and the 2nd sound absorption material are arrange | positioned over the perimeter of a pipe wall. In addition to this, for the first straight pipe disposed adjacent to the wall of the silencer body, the first small hole group and the first sound absorbing material are disposed on the pipe wall portion facing the second straight pipe. Yes. In other words, a space where the first sound absorbing material can be arranged cannot be secured on the side adjacent to the wall portion, but the space can be secured on the tube wall portion facing the second straight tube, so that the space is effectively utilized. And the 1st small hole group and the 1st sound-absorbing material are arrange | positioned. As described above, since the first straight pipe is adjacent to the wall portion, the arrangement of the sound absorbing material is not avoided, but the first straight pipe is provided with the sound absorbing material as much as possible. The silencing effect can be further enhanced.

  In the exhaust silencer described above, it is preferable that the exhaust pipe further includes a curved pipe connecting the first straight pipe and the second straight pipe.

  According to this exhaust silencer, it is possible to form an exhaust pipe having a long continuous pipe length by the first and second straight pipes and the curved pipe. Here, in order to make the exhaust flow smooth in the curved pipe, it is necessary to increase the curved diameter of the curved pipe accordingly. Accordingly, a corresponding space is naturally formed between the first and second straight tubes. Therefore, the first sound absorbing material can be arranged using the corresponding space.

  In the exhaust silencer, the first sound absorbing material cover covering the first sound absorbing material, the second sound absorbing material cover covering the second sound absorbing material, the first sound absorbing material cover, and the second sound absorbing material cover, It is desirable to further include a connecting member for connecting the two.

  According to this exhaust silencer, the shape retention of the first and second sound absorbing materials can be improved by installing the first and second sound absorbing material covers. Moreover, the support rigidity of a 1st, 2nd straight tube can be improved by connecting 1st, 2nd sound-absorbing material covers with a connection member.

  In the exhaust silencer, the first sound absorbing material cover that covers the first sound absorbing material, the second sound absorbing material cover that covers the second sound absorbing material, the first sound absorbing material cover, and the second sound absorbing material cover include: It is desirable to further include a set plate for supporting the first straight tube and the second straight tube with the silencer body at the arranged position.

  According to this exhaust silencer, the first and second sound absorbing material covers are connected to each other by the set plate, and these are also attached to the silencer body. Therefore, the support rigidity of the first and second straight pipes can be further increased. Moreover, the rigidity of the silencer body itself can be increased by adding a set plate.

  In the exhaust silencer, the silencer body includes, as walls defining the silence space, a front wall and a rear wall arranged in the front-rear direction of the vehicle, and a pair of side walls arranged in the vehicle width direction of the vehicle. The wall portion having a longitudinal shape in the vehicle width direction and the linearly extending wall portion is the front wall, and the exhaust pipe includes an exhaust introduction pipe for introducing engine exhaust into the silencing space, and the silencing space An exhaust lead pipe that discharges the exhaust to the outside, wherein the curved pipe, the first straight pipe, and the second straight pipe constitute at least a part of the exhaust lead pipe in the silencing space, It is desirable that the exhaust inlet pipe has an exhaust outlet disposed at a position near the rear wall, and the exhaust outlet pipe has an exhaust inlet disposed at a position near the front wall.

  According to this exhaust silencer, the exhaust outlet of the exhaust introduction pipe is arranged in the vicinity of the rear wall of the silencer body, while the exhaust inlet of the exhaust outlet pipe is arranged in the vicinity of the front wall. As a result, the exhaust outlet and the exhaust inlet can be moved away from each other in the silencing space, and the exhaust noise of the exhaust inlet pipe can be made difficult to be transmitted to the exhaust outlet pipe.

  In this case, the end of the first straight pipe opposite to the end connected to the curved pipe is the exhaust inlet, and the exhaust inlet is disposed at a position close to one of the pair of side walls. More desirable structure. As a result, the exhaust outlet and the exhaust inlet can be further away.

  In the exhaust silencer, the exhaust introduction pipe is disposed at a central position in the vehicle width direction of the silencer main body, and the exhaust lead-out pipe is sandwiched between the exhaust introduction pipes and is out of the pair of side walls. It is desirable to include a first exhaust outlet pipe disposed on one side and a second exhaust outlet pipe disposed on the other side.

  According to this exhaust silencer, it becomes easy to construct a structure in which exhaust resistance hardly occurs in the exhaust introduction pipe. Further, the exhaust lead-out pipe has an advantage that it is easy to secure a required pipe length by effectively using the silencing space.

  According to the present invention, a sound absorbing material can be arranged on the outer periphery of the exhaust pipe as much as possible even when there is a restriction that the wall portion of the silencer body and the exhaust pipe must be arranged adjacent to each other. Therefore, it is possible to provide an engine exhaust silencer with improved noise reduction performance.

FIG. 1 is a schematic diagram of an exhaust system of a vehicle to which an engine exhaust silencer according to the present invention is applied. FIG. 2 is a top view of the main silencer (exhaust silencer) according to the first embodiment of the present invention with the upper plate removed. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a perspective view of the main muffler, and is a perspective view showing a portion on the right side of the cross section shown in FIG. 4. FIG. 6 is a perspective view mainly showing the first straight tube and the second straight tube. FIG. 7 is a perspective view of the bending tube. FIG. 8 is a perspective view of a state in which first and second sound absorbing material covers are attached to the first and second straight pipes shown in FIG. 6, respectively. FIG. 9 is a perspective view of the main muffler according to the second embodiment of the present invention with the upper plate removed. FIG. 10 is a perspective view of the main part of FIG. 11 is a cross-sectional view taken along line XI-XI in FIG.

[Vehicle exhaust system]
Hereinafter, an engine exhaust silencer according to an embodiment of the present invention will be described in detail with reference to the drawings. First, an exhaust system of a vehicle on which the exhaust silencer is mounted will be schematically described with reference to FIG. In FIG. 1 and other drawings, front / rear, left / right and up / down direction indications are attached. These directions are relative to the vehicle. That is, the front-rear, left-right, and up-down directions used in the following description are perpendicular to the front-rear direction (vehicle front-rear direction), left-right direction (vehicle width direction) shown in FIG. The direction is the same as the vertical direction. Further, when referring to upstream and downstream, the flow direction of the exhaust is used as a reference.

  The vehicle is, for example, a four-wheeled vehicle, and includes an engine 1 and an exhaust device 10 that constitutes an exhaust system of the engine 1. The engine 1 is, for example, an in-line four-cylinder turbocharged gasoline engine, and is installed horizontally in the engine compartment in front of the vehicle compartment, that is, with the cylinders arranged in the vehicle width direction. The exhaust device 10 is connected to the engine 1 and extends rearward along the lower surface of the vehicle.

  The exhaust device 10 includes an exhaust manifold 11, a turbocharger 12, an exhaust pipe 13, a first catalyst device 14, a second catalyst device 15, a pre-silencer 16, and a main silencer 2 (exhaust silencer). . The exhaust manifold 11 has a branch end connected to an exhaust port of each cylinder head of the engine 1 on the upstream side, and an exhaust passage having a collective end on the downstream side for collecting exhaust discharged from these exhaust ports into one flow path. Is provided inside. The turbocharger 12 is connected to the collective end of the exhaust manifold 11 and supercharges the intake air of the engine 1 using the energy of the exhaust discharged from the engine 1.

  The exhaust pipe line 13 is a pipe line serving as an exhaust passage, and is connected to the downstream end of the turbocharger 12 and extends rearward. A first catalyst device 14, a second catalyst device 15, and a pre-silencer device 16 are incorporated in the exhaust pipe line 13 in order from the upstream side, and the main silencer device 2 is connected to the end. The first and second catalytic devices 14 and 15 purify harmful components in the exhaust discharged from the engine 1, for example, a catalyst including a NOx storage reduction catalyst that temporarily stores NOx in the exhaust and then reduces it. It is comprised from the main body and the casing which accommodates this catalyst main body.

  The pre-silencer 16 and the main silencer 2 are incorporated in the exhaust system of the engine 1 to reduce exhaust noise. Of these silencers 16 and 2, the pre-muffler 16 disposed on the upstream side mainly has a function of reducing high-frequency components in the exhaust noise. The pre-silencer 16 can employ, for example, a sound-absorption-type silencer, and is filled between a porous inner cylinder pipe through which exhaust passes, an outer cylinder pipe covering the porous inner cylinder pipe, and the inner cylinder pipe and the outer cylinder pipe Sound absorbing material such as glass wool. On the other hand, the main silencer 2 mainly has a function of reducing low and medium frequency components in the exhaust noise. Hereinafter, the structure of the main silencer 2 will be described in detail.

[Overall structure of main muffler according to first embodiment]
2 is a top view of the main muffler 2 according to the first embodiment (a state in which an upper plate 20A described later is removed), FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2, and FIG. It is IV-IV sectional view. FIG. 5 is a perspective view of the main muffler 2, and is a perspective view showing a portion on the right side of the cross section shown in FIG. 4. The main silencer 2 is disposed below the rear floor at the rear end of the vehicle, and includes a silencer body 20, an exhaust introduction pipe 3, a first exhaust lead pipe 4A, and a second exhaust lead pipe 4B (exhaust pipe).

  The silencer body 20 is a housing that forms a silencing space S (expansion chamber) into which exhaust of the engine 1 is introduced. The silencer body 20 has a relatively short shape in the front-rear direction and a relatively long shape in the left-right direction, that is, a shape that is long in the vehicle width direction and flat in the up-down direction, and has a rounded rectangular shape as a whole. . Thereby, the silencing space S in the silencer body 20 is also a long and flat space in the vehicle width direction.

  The silencer body 20 includes a front wall 21 and a rear wall 22 aligned in the front-rear direction of the vehicle, and a right wall 23 and a left wall 24 (a pair of side walls) aligned in the left-right direction (vehicle width direction) as walls that define the silence space S. ) And an upper wall 25 and a lower wall 26 arranged in the vertical direction (vehicle height direction). The front wall 21 is a wall that extends linearly in the left-right direction. The rear wall 22 is a wall that is curved so as to have a gentle convex shape toward the rear in a top view and extends in the left-right direction. The right wall 23 and the left wall 24 are short walls extending linearly in the front-rear direction, and connect the front wall 21 and the rear wall 22 on the right end side and the left end side, respectively. As shown in FIG. 3, the left wall 24 has a substantially semicircular curved shape in the left-right cross-sectional view (the same applies to the right wall 23). The upper wall 25 is a wall that seals the upper surface of the space surrounded by the side walls including the front wall 21, the rear wall 22, the right wall 23, and the left wall 24, and the lower wall 26 is a wall that seals the lower surface of the side wall. is there.

  The silencer body 20 is a joined body of an upper plate 20A and a bottom plate 20B, which is a half-cracked housing divided in the vertical direction. The upper plate 20A is a half-cracked housing having a cavity bulging upward, and has an upper flange portion 201 on the outer periphery of the lower edge thereof. The bottom plate 20B is a half-cracked housing having a cavity that bulges downward, and has a lower flange portion 202 on the outer periphery of its upper edge.

  The upper plate 20A forms the upper wall 25 and the upper half of the side wall, and the bottom plate 20B forms the lower wall 26 and the lower half of the side wall. The upper flange portion 201 and the lower flange portion 202 are overlaid and joined together so that the upper plate 20A and the bottom plate 20B are integrated, and the silencer body 20 having the silencing space S is formed. The upper wall 25 of the upper plate 20A and the lower wall 26 of the bottom plate 20B are provided with a plurality of beads 203 extending in the front-rear direction. The bead 203 is a groove-shaped portion that protrudes toward the silencing space S, and is provided for the purpose of increasing the rigidity of the silencer body 20.

  The exhaust introduction pipe 3, the first exhaust lead-out pipe 4 </ b> A, and the second exhaust lead-out pipe 4 </ b> B are exhaust pipes that constitute an exhaust path through which the exhaust passes in the silencing space S. That is, the pipe is arranged to flow the exhaust gas along a desired path in a closed space called the silencing space S. The exhaust introduction pipe 3, the first exhaust lead-out pipe 4A, and the second exhaust lead-out pipe 4B are pipes separated from each other. The exhaust introduction pipe 3 has an exhaust outlet A through which exhaust is blown out to the silencing space S. On the other hand, the first and second exhaust outlet pipes 4A and 4B each have a first exhaust inlet B1 and a second exhaust inlet B2 for taking in the exhaust in the silencing space S. Exhaust gas discharged from the exhaust outlet A enters the silencing space S, expands, and is then taken into the first and second exhaust inlets B1 and B2, and is discharged to the outside through the first and second outlet openings C1 and C2, respectively. Is done.

  The exhaust introduction pipe 3 is a linear hollow circular pipe that introduces exhaust of the engine 1 into the silencing space S. A relay pipe 31 is inserted on the upstream side of the exhaust introduction pipe 3. The upstream end of the relay pipe 31 is connected to the downstream end of the exhaust pipe 13. The downstream end of the exhaust introduction pipe 3 is the exhaust outlet A described above. The exhaust outlet A faces the rear wall 22.

  The exhaust introduction pipe 3 passes through the front wall 21 in the vicinity of the center in the left-right direction (the center position in the vehicle width direction), and is disposed in the silence space S so that the exhaust outlet A approaches the rear wall 22. That is, as shown in FIG. 2, the exhaust introduction pipe 3 is silenced from the front wall 21 side so that the exhaust outlet A is disposed closer to the rear wall 22 than the center of the silencer body 20 in the front-rear direction. It is inserted toward the space S. In the present embodiment, a later-described rectifying plate 6 is disposed between the exhaust outlet A and the rear wall 22. In another embodiment in which the current plate 6 is not used, the exhaust outlet A may be closer to the rear wall 22.

  The exhaust introduction pipe 3 is supported by a pipe receiving portion 204 (see FIGS. 6 and 8) which is a concave portion provided at the center in the left-right direction of the front wall 21 of the bottom plate 20B. Further, the vicinity of the exhaust outlet A of the exhaust introduction pipe 3 is supported by the support plate 32. The support plate 32 is a sheet metal member provided with a support hole that penetrates and supports the exhaust introduction pipe 3. The upper end side of the support plate 32 is fixed to the upper wall 25, and the lower end side is fixed to the lower wall 26. The exhaust introduction pipe 3 is attached to the silencer body 20 so as to rise rearward so that the exhaust outlet A faces slightly upward. This is because moisture (condensed water) in the exhaust gas condensed in the silencing space S may stay on the lower wall 26, and the retained water does not flow back to the exhaust introduction pipe 3 through the exhaust outlet A. It is.

  The first exhaust lead-out pipe 4A and the second exhaust lead-out pipe 4B are pipes for discharging the exhaust from the sound deadening space to the outside. The first and second exhaust lead-out pipes 4A and 4B have the same components, and are arranged in the silencing space S symmetrically to the left and right of the exhaust introduction pipe 3. That is, the first exhaust outlet pipe 4A is disposed on the right wall 23 side and the second exhaust outlet pipe 4B is disposed on the left wall 24 side with the exhaust inlet pipe 3 interposed therebetween. The first and second exhaust outlet pipes 4A and 4B each include a first straight pipe 41, a second straight pipe 42, and a curved pipe 43. The curved tube 43 is a tube curved in a U shape. The first straight tube 41 and the second straight tube 42 extend in parallel in the left-right direction from both ends of the bending tube 43 in a state of being close to each other. FIG. 6 is a perspective view of the first straight tube 41 and the second straight tube 42, and FIG. Note that the first and second straight tubes 41 and 42 may be arranged substantially in parallel even if they are not arranged in parallel.

  In the exhaust flow F of the first and second exhaust outlet pipes 4A and 4B, the first straight pipe 41 is an exhaust pipe disposed on the upstream side of the second straight pipe 42. The first straight pipe 41 is arranged so as to be adjacent to the front wall 21 extending linearly. That is, the distance in the front-rear direction between the front side portion of the first straight tube 41 and the front wall 21 is narrow. On the other hand, the second straight tube 42 is disposed at a substantially central position in the front-rear direction of the sound deadening space S, which is separated from the front wall 21 and also from the rear wall 22. The height positions in the vertical direction of the first straight tube 41 and the second straight tube 42 are substantially the same. The bending tube 43 connects the first and second straight tubes 41 and 42 to each other.

  FIG. 3 shows a cross section in the left-right direction of the first straight pipe 41 of the second exhaust lead-out pipe 4B and the exhaust flow F. The first straight tube 41 is a tube having a circular cross section that extends linearly in the left-right direction, and includes an upstream end 411 (the opposite end) and a downstream end 412 (a connection end to the curved tube). The upstream end 411 is a pipe end provided with an opening that becomes the above-described second exhaust inlet B2 (in the case of the first straight pipe 41 of the first exhaust outlet pipe 4A, the first exhaust inlet B1). The upstream end 411 is processed to increase the inner diameter in a bell mouth shape so that the exhaust gas can be smoothly taken into the second exhaust inlet B2. The downstream end 412 is a tube end portion that is inserted into the upstream end 431 of the bending tube 43.

  As described above, the exhaust outlet A is disposed in the vicinity of the rear wall 22 (in the present embodiment, in the vicinity of the rectifying plate 6 substantially corresponding to the rear wall 22), whereas the first and second The exhaust inlets B <b> 1 and B <b> 2 are disposed in the vicinity of the front wall 21 because the first straight pipe 41 is adjacent to the front wall 21. Further, the exhaust outlet A is disposed at a central position in the left-right direction, whereas the first and second exhaust inlets B1 and B2 are disposed on the right end side and the left end side of the front wall 21, respectively. Specifically, the first exhaust inlet B1 faces the right wall 23 near the front wall 21, the second exhaust inlet B2 faces the left wall 24 near the front wall 21, and is close to the right wall 23 and the left wall 24, respectively. Placed in position. In this way, by separating the exhaust outlet A from the first and second exhaust inlets B1 and B2, the exhaust noise of the exhaust introduction pipe 3 is hardly transmitted to the first and second exhaust lead-out pipes 4A and 4B. Yes.

  The second straight tube 42 is a tube having a circular cross section that extends linearly in the left-right direction, and is a tube having a longer left-right width than the first straight tube 41. The upstream end of the second straight tube 42 is inserted into the downstream end 432 (FIG. 7) of the bending tube 43. The downstream end of the second straight pipe 42 of the first exhaust outlet pipe 4A passes through the right wall 23. A first tail pipe 44A is connected to the penetrated downstream end. Further, the downstream end of the second straight pipe 42 of the second exhaust outlet pipe 4 </ b> B penetrates the left wall 24. A second tail pipe 44B is connected to the penetrated downstream end. The downstream end of the first tail pipe 44A is a first outlet opening C1, and the downstream end of the second tail pipe 44B is a second outlet opening C2. Exhaust gas is discharged to the outside through the first and second outlet openings C1 and C2.

  Referring to FIGS. 3 and 7, the curved tube 43 is a tube that forms an exhaust path that is substantially circular in cross section and curved in a U shape. As described above, the bending tube 43 includes the upstream end 431 to which the first straight tube 41 is connected and the downstream end 432 to which the second straight tube 42 is connected. The curved tube 43 is composed of a joined body of a first half-cracked tube 43A and a second half-cracked tube 43B that are half-cracked tubes divided in the vertical direction. 43 A of 1st half crack pipes and 43 B of 2nd half crack pipes are mutually joined by the outer peripheral flange part 433 and the inner peripheral flange part 434. FIG. The outer peripheral flange portion 433 extends outward from the outer curved portion L1 of the curved tube 43 curved in a U shape. On the other hand, the inner peripheral flange portion 434 extends inward from the inner curved portion L2 so as to fill a U-shaped space defined by the inner curved portion L2 of the curved tube 43.

  The first half-cracked tube 43A has a semicircular cross section bulging upward, has a U-shaped cavity in a bottom view, and has an upper flange portion 433A that forms the upper side of the outer peripheral flange portion 433 on the outer peripheral side. The upper flange portion 434A that forms the upper side of the peripheral flange portion 434 is provided on the inner peripheral side. The second half-cracked tube 43B has a semicircular cross-section that bulges downward, has a U-shaped cavity in top view, and has a lower flange portion 433B that forms the lower side of the outer peripheral flange portion 433 on the outer peripheral side. The lower flange portion 434B that forms the lower side of the inner peripheral flange portion 434 is provided on the inner peripheral side. The upper flange portion 433A and the lower flange portion 433B, and the upper flange portion 434A and the lower flange portion 434B are vertically overlapped and joined, whereby the bending tube 43 is formed.

  The bending tube 43 includes non-flange portions 435 at the upstream end 431 and the downstream end 432, respectively. The non-flange portion 435 is a cylindrical portion where the outer peripheral flange portion 433 and the inner peripheral flange portion 434 do not exist in the bending tube 43. In the non-flange portion 435, there are slits SL having an opening width corresponding to the thickness of the outer peripheral flange portion 433 and the inner peripheral flange portion 434 and the bending allowance thereof. As shown in FIG. 3, the downstream end 412 of the first straight pipe 41 is inserted into the non-flange portion 435. Although not shown, the upstream end of the second straight pipe 42 is also inserted into the non-flange portion 435 on the downstream end 432 side. The downstream end 412 of the first straight pipe 41 is inserted into the bending pipe 43 to a position that reaches the outer peripheral flange part 433 beyond the non-flange part 435. The same applies to the upstream end of the second straight pipe 42. As a result, the air leakage passage from the slit SL is blocked, and airflow noise is prevented from being generated.

  As shown in FIGS. 3 and 5, the bending tube 43 is supported by the silencer body 20 by the set plate 27. The set plate 27 is a flat plate member extending in the vertical direction, and has an upper flange portion 271 at the upper end side, a lower flange portion 272 at the lower end side, and two burring portions 273 at the center. In each burring portion 273, the upstream end 431 of the bending tube 43 and the non-flange portion 435 of the downstream end 432 are densely inserted. That is, the burring portion 273 supports the non-flange portion 435 into which one ends of the first and second straight pipes 41 and 42 are inserted.

  The upper flange portion 271 is joined to the upper wall 25, and the lower flange portion 272 is joined to the lower wall 26. The upper wall 25 is provided with a welding hole (not shown), and the upper flange portion 271 is fixed to the upper wall 25 by plug welding. The lower flange portion 272 is fixed to the lower wall 26 by spot welding. In this way, by forming the non-flange portion 435, a simple support structure of the bending tube 43, that is, a structure in which the bending tube 43 is supported by the set plate 27 including the burring portion 273 having a simple round hole is realized. In addition, the first and second straight tubes 41 and 42 can also be supported by the set plate 27.

  The main silencer 2 includes a first silencer 51 applied to the first straight tube 41, a second silencer 52 applied to the second straight tube 42, and a curved silencer 53 applied to the curved tube 43. Is provided. These silencers 51 to 53 include a large number of small holes drilled in each tube wall, a sound absorbing material that covers the outer periphery of the tube wall portion having these small holes, and a sound absorbing material cover that covers the periphery of the sound absorbing material. Consists of. When airflow sound (exhaust noise) is generated in the exhaust gas passing through the first and second exhaust lead-out pipes 4A and 4B, the airflow sound is released outside the pipe through the small holes and is absorbed by the sound absorbing material. The sound absorbing material is, for example, glass wool. These silencers 51 to 53 will be described in detail later.

  The main silencer 2 further includes a current plate 6. The rectifying plate 6 is disposed at a position facing the exhaust outlet A, and includes a guide surface that guides exhaust from the exhaust outlet A toward the rear wall 22 in the left-right direction (both sides in the vehicle width direction). The rectifying plate 6 includes a tip portion that faces the central portion in the left-right direction of the exhaust outlet A, and the guide surface extends from the tip portion to the left and right rear. Exhaust gas blown out from the exhaust outlet A is diverted at the tip, and travels left and right along the left and right guide surfaces and the rear wall 22. Exhaust air that has been split to the left and right blows to the right wall 23 and the left wall 24, and the corners of the rear wall 22, the right wall 23, and the left wall 24 are rounded, It goes forward along the wall 23 and the left wall 24. Thereafter, the exhaust enters the first and second exhaust inlets B1 and B2 and passes through the first and second exhaust outlet pipes 4A and 4B.

  The rectifying plate 6 is supported by the upper wall 25 and the lower wall 26 of the silencer body 20. That is, a flange portion 61 is provided on the upper end side of the rectifying plate 6, and the flange portion 61 is fixed to the upper wall 25 by plug welding. On the other hand, the lower end side of the current plate 6 is attached to the lower wall 26 via the attachment plate 28. The mounting plate 28 extends in the left-right direction across the bead 203 and provides a seating surface for the rectifying plate 6. The flange portion on the lower end side of the rectifying plate 6 is fixed to the mounting plate 28 by spot welding, and the mounting plate 28 is fixed to the lower wall 26 by spot welding.

[Details of silencer]
Next, the first silencer 51 applied to the first straight tube 41, the second silencer 52 applied to the second straight tube 42, and the curved silencer 53 applied to the curved tube 43 will be described in detail. . In the description, FIG. 8 is referred to in addition to FIGS. FIG. 8 is a perspective view showing a state in which the first and second sound absorbing material covers 511 and 512 are attached to the first and second straight pipes 41 and 42 shown in FIG. 6, respectively.

  The first silencer 51 is provided in a part of the circumferential direction in a predetermined region of the first straight tube 41 in the tube axis direction. Referring mainly to FIGS. 4 to 6, the first silencer 51 includes a first small hole group H <b> 1 composed of a large number of small holes 41 </ b> H drilled in the tube wall of the first straight pipe 41, and the first straight pipe. 41, and a first sound absorbing material cover 511 attached to the first straight tube 41 so as to cover the first sound absorbing material 71.

  The small hole 41H is a hole that communicates the inside and outside of the first straight pipe 41 with each other. The first small hole group H1 is formed by drilling a large number of small holes 41H in a matrix shape on the tube wall. The first small hole group H <b> 1 is arranged (perforated) in substantially the entire region (predetermined region) excluding the region near the upstream end 411 and the downstream end 412 in the tube axis direction of the first straight tube 41. On the other hand, with respect to the circumferential direction of the first straight tube 41, it is perforated only in the rear tube wall portion substantially opposite to the second straight tube 42 in the entire circumference of the first straight tube 41.

  In the present embodiment, both pipes are arranged in the silencer body 20 so that the pipe axis P1 of the first straight pipe 41 and the pipe axis P2 of the second straight pipe 42 are substantially at the same height. Then, as shown in FIG. 4, in the cross-sectional view in the direction of the pipe axis P <b> 1, the arc near the center in the vertical direction among the side portions of the rear half of the first straight pipe 41 serving as the opposing pipe wall portion The tube wall portion (upper and lower circular arc regions centered on the line connecting P1 and P2) is the drilling range of the small hole 41H. FIG. 4 shows an example in which the arc tube wall portion having the central angle θ = 45 ° is the perforation range, but this is an example. For example, the perforation range of the small hole 41H can be selected from the range of the central angle θ = about 30 ° to 150 °.

  The first sound absorbing material 71 is partially arranged on the outer periphery of the first straight tube 41 so as to cover the tube wall portion in which the first small hole group H1 is perforated. In other words, the first sound absorbing material 71 has a predetermined thickness in the radial direction of the first straight tube 41 so as to be in contact with the outer peripheral surface of the tube wall portion of the first straight tube 41 in the drilling range of the small hole 41H. Is arranged.

  The first sound absorbing material cover 511 is attached to the outer peripheral surface of the first straight tube 41 so as to cover the first sound absorbing material 71. The first sound absorbing material cover 511 includes a bulging portion 512 serving as a cavity for housing the first sound absorbing material 71, and a flange-like joint portion 513 provided above and below the bulging portion 512. The bulging portion 512 has a size that completely covers the first small hole group H1 in both the first tube axis P1 direction and the circumferential direction. The pair of upper and lower joint portions 513 are joined to the outer peripheral surface of the first straight tube 41 by wire welding or the like.

  The first silencer 51 is partially arranged with respect to the first straight tube 41 as described above because the first sound absorbing material 71 and the first sound absorbing material cover 511 are arranged in the space of the first straight tube 41. This is because it cannot be secured on the front side. As shown in FIG. 4, since the first straight tube 41 is disposed adjacent to the front wall 21, the distance d in the front-rear direction between the front side portion of the first straight tube 41 and the front wall 21 is small. It is. For this reason, the sound-absorbing material 71 and the first sound-absorbing material cover 511 cannot be disposed with sufficient space on the front side portion. If these are forcibly arranged, the first sound-absorbing material cover 511 may come into contact with the front wall 21 due to running vibration of the vehicle and generate abnormal noise. On the other hand, an empty space corresponding to the front-rear width of the bending tube 43 can be secured on the side portion on the rear side of the first straight tube 41. That is, there is a space between the first straight tube 41 and the second straight tube 42 arranged in parallel via the curved tube 43, and there is no interfering member. For this reason, the first silencer 51 is provided only on the rear side of the first straight tube 41.

  The second silencer 52 is provided so as to cover the entire circumference of the tube wall in a predetermined region of the second straight tube 42 in the tube axis direction. The second silencer 52 includes a second small hole group H2 composed of a large number of small holes 42H perforated in the tube wall of the second straight tube 42, and a second sound absorbing material 72 disposed on the outer periphery of the second straight tube 42. And a second sound absorbing material cover 521 attached to the second straight tube 42 so as to cover the second sound absorbing material 72.

  The small hole 42H is a hole that allows the inside and outside of the second straight pipe 42 to communicate with each other. A large number of small holes 42H are drilled in a matrix on the tube wall, thereby forming the second small hole group H2. As shown in FIG. 6, the second small hole group H2 is perforated in a central region (predetermined region) of the second straight tube 42 in the second tube axis direction P2. Further, the circumferential direction of the second straight tube 42 is perforated over the entire circumference of the tube wall of the first straight tube 41.

  The second sound absorbing material 72 is disposed on the outer periphery of the second straight tube 42 so as to cover the entire circumference of the tube wall region in which the second small hole group H2 is perforated. That is, the second sound-absorbing material 72 has a predetermined thickness in the radial direction of the second straight tube 42, the entire perforation range of the small holes 42H in the second tube axis P2 direction of the second straight tube 42, and its It arrange | positions at a cylinder shape so that the outer peripheral surface of the pipe wall part of the whole range of the circumferential direction may be contact | connected.

  The second sound absorbing material cover 521 is attached to the outer peripheral surface of the second straight tube 42 so as to cover the outer periphery of the cylindrical second sound absorbing material 72. The second sound absorbing material cover 521 is composed of a joined body of a pair of half-cracked members. Each of the half-crack members includes a half-crack cover main body 522, an end joint portion 523, and a flange portion 524. The half-cracked cover main body 522 is a bulging portion serving as a cavity for accommodating the second sound absorbing material 72, and has an inner diameter larger than the outer diameter of the second straight tube 42 as shown in FIG. The half-cracked cover main body 522 has a size that completely covers the second small hole group H2 in the direction of the second tube axis P2.

  The end joints 523 are circumferential joints attached to the left and right ends of the half-cracked cover main body 522 and have a curved shape along the outer peripheral surface of the second straight tube 42. The end joints 523 are joined to the outer peripheral surface of the second straight tube 42 by spot welding or the like. The flange portion 524 is a joint surface for joining a pair of half-cracked cover main bodies 522 to form a cylindrical body. The flange portion 524 extends from the left and right end portions of the half-cracked cover body 522 in the direction of the second tube axis P2.

  The second straight tube 42 is disposed at a substantially central position in the front-rear direction of the silencer body 20. For this reason, the second straight tube 42 is separated from both the front wall 21 and the rear wall 22, and the first straight tube 41 is spaced from the first straight tube 41 according to the longitudinal width of the curved tube 43. Yes. Therefore, since there is a space margin, the second sound absorbing material 72 and the second sound absorbing material cover 521 can be attached so as to cover the entire circumference of the second straight tube 42.

  The first sound absorbing material cover 511 and the second sound absorbing material cover 521 are connected by a connecting member 54. The connecting member 54 is a sheet metal member extending in the front-rear direction, and includes a front joint portion 541 and a rear joint portion 542 (FIGS. 4 and 8). The front joint portion 541 is joined to the upper side surface of the bulging portion 512 of the first sound absorbing material cover 511 by wire welding. On the other hand, the rear joint portion 542 is joined by wire welding near the front upper side portion of the half-cracked cover main body 522 of the second sound absorbing material cover 521.

  As shown in FIGS. 3 and 7, the curved silencer 53 includes a large number of small holes 43H drilled in the vicinity of the bulging tops of the first half cracked tube 43A and the second half cracked tube 43B, and the small holes 43H. A third sound-absorbing material 73 that covers the outer peripheral surfaces of the first and second half-broken pipes 43A and 43B, and an upper cover 53A and a lower cover 53B (sound-absorbing material cover) that respectively cover the third sound absorbing material 73. Yes. The third sound absorbing material 73 is disposed along the substantially entire region of the outer peripheral surface of the bulging portion of the first and second half cracked tubes 43A and 43B in the portion excluding the non-flange portion 435 of the bending tube 43. . The small hole 43H drilled near the top of the bulging portion is completely covered with the third sound absorbing material 73.

  The upper cover 53A covers the third sound absorbing material 73 on the outer periphery of the first half cracked tube 43A, and the lower cover 53B covers the third sound absorbing material 73 on the outer periphery of the second half cracked tube 43B. Each of the upper cover 53A and the lower cover 53B has a partial flange 531 on the outer curved portion L1 side of the bending tube 43 and an attachment portion 532 on the inner curved portion L2 side. The partial flange 531 is a flange portion having a shape partially overlapping with the upper and lower flange portions 433A and 433B, respectively.

  The upper flange portion 433A of the first half cracked tube 43A and the partial flange 531 of the upper cover 53A, and the lower flange portion 433B of the second half cracked tube 43B and the partial flange 531 of the lower cover 53B are spotted in the respective overlapping portions. It is joined by welding. The upper and lower flange portions 433A and 433B are joined by spot welding at a non-overlapping portion of the partial flange 531. That is, in the outer peripheral flange portion 433, the upper and lower flange portions 433A and 433B and the upper and lower partial flanges 531 are overlapped with each other, but the respective joints are made by two-layer spot welding. The attachment portion 532 is a curved portion in contact with the outer peripheral surface of the bulging portion of each of the first and second half cracked tubes 43A and 43B in the vicinity of the upstream end 431 (downstream end 432) of the curved tube 43. For the inner curved portion L2 side, the upper and lower covers 53A and 53B can be joined to the outer peripheral surface of the curved tube 43, for example, by wire welding.

[Effects]
The main silencer 2 according to the first embodiment described above has the following operational effects. First, since the first exhaust lead-out pipe 4A and the second exhaust lead-out pipe 4B, which are exhaust pipes arranged in the silencing space S, include the first, second straight pipes 41 and 42 and the curved pipe 43, respectively, the silencing space The length of the exhaust pipe in S can be increased. Thereby, the reduction degree of the exhaust noise in 1st, 2nd exhaust derivation | leading-out pipe | tube 4A, 4B itself can be raised.

  Furthermore, the silencing effect is enhanced by the application of the first and second sound absorbing materials 71 and 72 to the first and second straight tubes 41 and 42 and the application of the third sound absorbing material 73 to the curved tube 43. ing. That is, with respect to the second straight pipe 42 disposed away from the front wall 21 and the rear wall 22 of the silencer main body 20, the second small hole group H2 and the second sound absorbing material are arranged over the entire circumference of the pipe wall. 72 is arranged. As for the bending tube 43, a third sound absorbing material 73 is attached to the outer peripheral surface of both the first and second half-breaking tubes 43A and 43B.

  In addition to this, the first straight tube 41 disposed adjacent to the front wall 21 of the silencer body 20 also has the first small hole group H1 and the first sound absorption in the tube wall portion facing the second straight tube 42. A material 73 is arranged. That is, a space where the first sound absorbing material 73 can be arranged cannot be secured on the front side of the first straight tube 41 adjacent to the front wall 21, but the space can be secured on a tube wall portion facing the second straight tube 42. Therefore, the first small hole group H1 and the first sound absorbing material 71 are arranged using the space effectively. In this way, because the first straight pipe 41 avoids the arrangement of the sound absorbing material because it is adjacent to the front wall 21, the sound absorbing material is attached to the first straight pipe 41 as much as possible. The silencing effect in the first and second exhaust outlet pipes 4A and 4B is further enhanced.

  In addition, in the case where an exhaust pipe having a long continuous pipe length is formed by the first and second straight pipes 41 and 42 and the curved pipe 43, in order to make the exhaust flow smooth in the curved pipe 43, the curved diameter of the curved pipe 43 is set. It needs to be increased accordingly. Accordingly, a corresponding space is naturally formed between the first and second straight pipes 41 and 42. The structure in which the first and second straight tubes 41 and 42 are connected by the bending tube 43 according to the present embodiment is advantageous because the corresponding space can be used as the arrangement space for the first sound absorbing material 71.

  The main silencer 2 includes a first sound absorbing material cover 511 that covers the first sound absorbing material 71, a second sound absorbing material cover 521 that covers the second sound absorbing material 72, a first sound absorbing material cover 511, and a second sound absorbing material cover 521. And a connecting member 54 for connecting the two. By providing the first and second sound absorbing material covers 511 and 521, the shape retention of the first and second sound absorbing materials 71 and 72 can be improved. Further, by connecting the first and second sound absorbing material covers 511 and 521 with the connecting member 54, the first and second straight lines of the first and second exhaust outlet pipes 4 </ b> A and 4 </ b> B that are largely curved in a U shape. The pipes 41 and 42 are connected to each other, and the support rigidity is increased.

  Further, the exhaust outlet A of the exhaust introduction pipe 3 is disposed in the vicinity of the rear wall 22 of the silencer main body 20, while the first and second exhaust inlets B1, B2 of the first and second exhaust outlet pipes 4A, 4B. Is disposed in the vicinity of the front wall 21. As a result, the exhaust outlet A and the first and second exhaust inlets B1 and B2 can be moved away from each other in the silence space S, and the exhaust noise of the exhaust introduction pipe 3 is transmitted to the first and second exhaust inlets B1 and B2. Can be difficult. In particular, since the first exhaust inlet B1 and the second exhaust inlet B2 are arranged close to each other on the right wall 23 and the left wall 24, the exhaust outlet A and the first and second exhaust inlets are arranged. B1 and B2 are further away from each other, and the silencing effect is enhanced.

  Further, the exhaust introduction pipe 3 is disposed at a central position in the vehicle width direction of the silencer body 20, and the first and second exhaust lead-out pipes 4 </ b> A and 4 </ b> B sandwich the exhaust introduction pipe 3 with the right wall 23 side and the left side. They are arranged on the wall 24 side. For this reason, exhaust resistance hardly occurs in the exhaust introduction pipe 3. Further, the first and second exhaust outlet pipes 4A and 4B have an advantage that it is easy to ensure a required pipe length by effectively using the silencing space S.

[Main Silencer According to Second Embodiment]
9 is a perspective view of the main silencer 2A according to the second embodiment with the upper plate 20A removed, FIG. 10 is a perspective view of the main part of FIG. 9, and FIG. 11 is XI-XI of FIG. It is line sectional drawing. The main silencer 2A is different from the first embodiment in that a silencer set plate 29 (set plate) is used in place of the connecting member 54. Since the other points of the main silencer 2A are the same as those of the first embodiment, description thereof will be omitted.

  The silencer set plate 29 is arranged at the position where the first sound absorbing material cover 511 and the second sound absorbing material cover 521 are disposed, and the first and second straight pipes 41 and 42 of the first and second exhaust outlet pipes 4A and 4B. Is arranged to be supported by the silencer body 20. The pair of set plates 27 described above respectively support the non-flange portion 435 of the bending tube 43 into which one ends of the first and second straight tubes 41 and 42 are inserted. The pair of silencer set plates 29 are each arranged in parallel with the set plate 27 and are positioned closer to the right wall 23 and the left wall 24 than the set plate 27 (substantially the arrangement position of the connecting member 54 in the first embodiment). At the same position), the first and second straight tubes 41 and 42 are supported.

  The silencer set plate 29 is a flat plate member extending in the vertical direction, and includes a first support hole 291, a second support hole 292, an upper flange part 293, and a lower flange part 294. The first support hole 291 is a hole through which the first straight tube 41 to which the first sound absorbing material cover 511 is attached is inserted. A burring portion 291 </ b> A is formed on the inner peripheral edge of substantially the front half of the first support hole 291. The burring portion 291A supports a portion of the first straight tube 41 where the first sound absorbing material cover 511 is not mounted (see FIG. 11). There is a gap between the first sound absorbing material cover 511 and the inner periphery of the first support hole 291. The second support hole 292 is a hole through which the second straight tube 42 to which the cylindrical second sound absorbing material cover 521 is attached is inserted. A burring portion is provided over the entire inner periphery of the second support hole 292, and the second straight tube 42 is supported via the second sound absorbing material cover 521.

  The upper flange portion 293 is a flange portion provided on the upper end side of the silencer set plate 29, and the lower flange portion 294 is a flange portion provided on the lower end side. The upper flange portion 293 is joined to the upper wall 25 of the silencer body 20, and the lower flange portion 294 is joined to the lower wall 26. By adding such a silencer set plate 29, the support rigidity of the first and second straight pipes 41 and 42 can be further increased. Further, since the upper and lower flange portions 293 and 294 are joined to the upper wall 25 and the lower wall 26, respectively, the rigidity of the silencer body 20 itself can be increased.

[Description of Other Modified Embodiments]
As mentioned above, although two embodiment of this invention was described, this invention is not limited to these, A various deformation | transformation embodiment can be taken.

  (1) In the above embodiment, as an example of the exhaust pipe, the exhaust introduction pipe 3 and the first and second exhaust lead-out pipes 4A and 4B are arranged symmetrically on the left and right sides thereof, and the first and second exhaust lead-out pipes 4A 4B shows an example in which the first and second straight tubes 41 and 42 and the bending tube 43 are provided. This is an example, and one exhaust outlet pipe may be used. The first and second straight pipes 41 and 42 and the curved pipe 43 may be provided in the exhaust introduction pipe 3. Furthermore, in the present embodiment, the curved pipe 43 that changes the exhaust path by 180 ° is exemplified, but it is sufficient that the exhaust pipe is curved in a U shape, and the curve is slightly looser than 180 °, or slightly curved beyond 180 °. Also good. Further, the bent pipe 43 may not be present, and only the first and second straight pipes 41 and 42 may be an exhaust introduction pipe or an exhaust lead pipe that extends in close proximity and in parallel.

  (2) In the above embodiment, an example in which the front wall 21 is a linearly extending wall portion and the first straight pipe 41 is disposed adjacent to the front wall 21 of the silencer body 20 has been described. Alternatively, the first straight tube 41 may be disposed adjacent to the rear wall 22, the right wall 23, or the left wall 24, and the second straight tube 42 may be disposed apart from these walls. it can.

1 Engine 10 Exhaust device 2, 2A Main silencer (exhaust silencer)
20 Silencer body 21 Front wall (straightly extending wall)
22 Rear wall 23 Right wall (side wall)
24 Left wall (side wall)
29 Silencer set plate (set plate)
3 Exhaust pipe (exhaust pipe)
4A First exhaust outlet pipe (exhaust pipe)
4B Second exhaust outlet pipe (exhaust pipe)
41 First straight pipe 42 Second straight pipe 43 Curved pipe 511 First sound absorbing material cover 521 Second sound absorbing material cover 54 Connecting member 71 First sound absorbing material 72 Second sound absorbing material A Exhaust outlet B1 First exhaust inlet B2 Second exhaust Entrance S Silencing space H1 First small hole group H2 Second small hole group P1 First tube axis (tube axis of the first straight tube)
P2 2nd tube axis (tube axis of 2nd straight tube)

Claims (7)

A silencer body that forms a silencing space in which the exhaust of the vehicle engine is introduced;
An exhaust pipe that constitutes an exhaust path through which the exhaust passes in the silencing space, and includes a first straight pipe and a second straight pipe that extend substantially parallel to each other;
A first sound absorbing material disposed on the outer periphery of the first straight tube, and a second sound absorbing material disposed on the outer periphery of the second straight tube,
The silencer body includes a linearly extending wall that partitions the silencer space,
Each of the first and second straight pipes includes first and second small hole groups drilled in a pipe wall,
The first straight tube is disposed adjacent to the wall portion, while the second straight tube is disposed away from the wall portion,
The second small hole group is perforated over the entire circumference of the tube wall in a predetermined region in the tube axis direction of the second straight tube, and the second sound absorbing material covers the entire circumference of the tube wall. Arranged on the outer circumference of the second straight tube,
The first small hole group is perforated only in a tube wall portion substantially opposed to the second straight tube, of the entire circumference in a predetermined region in the tube axis direction of the first straight tube, An exhaust silencer for an engine, wherein the first sound absorbing material is disposed on an outer periphery of the first straight pipe so as to cover the pipe wall portion. The engine exhaust silencer according to claim 1,
The exhaust pipe silencer device further includes a curved pipe connecting the first straight pipe and the second straight pipe. The engine exhaust silencer according to claim 1 or 2,
A first sound absorbing material cover covering the first sound absorbing material, and a second sound absorbing material cover covering the second sound absorbing material;
An exhaust exhaust silencer for an engine, further comprising: a connecting member that connects the first sound absorbing material cover and the second sound absorbing material cover. The engine exhaust silencer according to claim 1 or 2,
A first sound absorbing material cover covering the first sound absorbing material, and a second sound absorbing material cover covering the second sound absorbing material;
An engine further comprising a set plate for supporting the first straight pipe and the second straight pipe with the silencer body at a position where the first sound absorbing material cover and the second sound absorbing material cover are disposed. Exhaust silencer. The engine exhaust silencer according to any one of claims 2 to 4,
The silencer body includes front and rear walls aligned in the front-rear direction of the vehicle and a pair of side walls aligned in the vehicle width direction of the vehicle as walls that define the silencer space, and is long in the vehicle width direction. And the linearly extending wall is the front wall,
The exhaust pipe includes an exhaust introduction pipe that introduces engine exhaust into the silencing space, and an exhaust outlet pipe that discharges the exhaust from the silencing space to the outside. The curved pipe, the first straight pipe, and the second straight pipe A pipe constitutes at least a part of the exhaust outlet pipe in the silencing space;
The exhaust inlet pipe has an exhaust outlet disposed at a position near the rear wall,
The exhaust exhaust pipe is an exhaust silencer for an engine, the exhaust inlet of which is disposed in the vicinity of the front wall. The engine exhaust silencer according to claim 5,
The exhaust pipe has an end opposite to the connection end of the first straight pipe to the curved pipe,
An exhaust silencer for an engine, wherein the exhaust inlet is disposed at a position close to one of the pair of side walls. The engine exhaust silencer according to claim 5 or 6,
The exhaust introduction pipe is disposed at a central position in the vehicle width direction of the silencer body,
The exhaust outlet pipe includes an engine exhaust pipe including a first exhaust outlet pipe disposed on one side of the pair of side walls and a second exhaust outlet pipe disposed on the other side across the exhaust inlet pipe. Exhaust silencer.

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