JP6468445B2 - 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 a structure for reducing exhaust noise, there is known a structure in which a large number of small holes are formed in an exhaust introduction pipe and / or an exhaust lead-out pipe and the periphery thereof is covered with a sound absorbing material such as glass wool. Patent Document 1 discloses a silencer in which a sound absorbing material filling space is created with a partition plate in a silencer body, and an exhaust pipe with a small hole is disposed so as to pass through the filling space.

JP 2005-344640 A

  In order to reduce the exhaust noise, the exhaust pipe length in the silencing space is made longer, and the exhaust outlet of the exhaust inlet pipe and the exhaust inlet of the exhaust outlet pipe are arranged so that the noise of the exhaust inlet pipe is difficult to transmit to the exhaust outlet pipe. It is desirable to separate as much as possible. However, when the above-described separation arrangement is adopted, an exhaust flow is formed between the exhaust outlet and the exhaust inlet in the silencing space. In this case, since airflow sound due to the exhaust flow can be generated, a countermeasure against the airflow sound is required.

  The object of the present invention is to mute the noise of the air flow caused by the exhaust flow from the exhaust outlet of the exhaust inlet pipe to the exhaust inlet of the exhaust outlet pipe, while silencing the exhaust noise of the exhaust inlet pipe and / or the exhaust outlet pipe with the sound absorbing material. It is an object of the present invention to provide an exhaust silencer for an engine.

An engine exhaust silencer according to one aspect of the present invention includes a silencer body having a wall portion that forms a silence space into which exhaust of a vehicle engine is introduced, a sound absorber, and the sound absorber in the silence space. A frame member that partitions a sound absorption chamber to be filled, an exhaust outlet, an exhaust introduction pipe that introduces the exhaust into the silencing space, and an exhaust that has an exhaust inlet and discharges the exhaust to the outside from the silencing space An exhaust passage formed by a wall portion of the silencer body and the frame member between the exhaust pipe and the exhaust inlet, and at least of the exhaust introduction pipe or the exhaust exhaust pipe On the other hand but has a sound absorbing pipe section passing through the sound absorbing chamber, the frame member may have a plurality of small holes communicating with said exhaust passage and said acoustic chamber, the wall portion of the muffler main body, the vehicle Front and rear walls lined up in the front-rear direction; It includes a pair of side walls arranged in the width direction, and an upper wall and a lower wall arranged in the vehicle vertical direction, the exhaust introduction pipe passes through the front wall, and the exhaust outlet is oriented in a direction in which the exhaust is directed to the rear wall. The exhaust lead-out pipe passes through the side wall, and the exhaust inlet is disposed at a position near the front wall and close to the side wall.

  According to this exhaust silencer, since at least one of the exhaust introduction pipe or the exhaust outlet pipe has the sound absorbing pipe portion that passes through the sound absorbing chamber filled with the sound absorbing material, it is possible to obtain the noise reduction effect by the sound absorbing material. Furthermore, an exhaust passage formed by a wall portion of the silencer body and a frame member that partitions the sound absorbing chamber is provided between the exhaust outlet and the exhaust inlet, and the sound absorbing chamber and the exhaust passage are communicated with the frame member. A number of small holes are drilled. For this reason, even if airflow noise is generated in the exhaust gas passing through the exhaust passage, the sound absorbing material absorbs sound through the small hole. Therefore, it is possible to mute the airflow sound caused by the exhaust flow from the exhaust outlet to the exhaust inlet.

  In the exhaust silencer described above, the wall portion of the silencer body includes a front wall and a rear wall arranged in the vehicle front-rear direction, a pair of side walls arranged in the vehicle width direction, and an upper wall and a lower wall arranged in the vehicle vertical direction. The silencer main body has a flat shape in which the upper wall and the lower wall are adjacent to the exhaust introduction pipe and the exhaust lead-out pipe, respectively, and the frame member includes the upper wall and the lower wall. It is desirable to extend between.

  According to this exhaust silencer, the vertical rigidity of the silencer body having a flat shape can be increased by the frame member that partitions the sound absorption chamber.

  In this case, the sound absorbing pipe portion has a large number of small holes that allow the inside of the pipe and the sound absorbing chamber to communicate with each other only in a portion corresponding to the upper region of the sound absorbing chamber, and the sound absorbing material includes all of the sound absorbing chamber. It is desirable to fill the area.

  In general, water generated by combustion in an engine is discharged to the outside from an exhaust outlet pipe. However, in the structure in which the exhaust introduction pipe and the exhaust lead pipe are adjacent to the lower wall of the silencer body, there is a concern that the exhaust introduction pipe and the exhaust lead pipe are immersed in the water staying in the silencer space, and further, water is exhausted from the exhaust introduction pipe. There is a concern of regurgitation. However, according to the exhaust silencer described above, a small hole is drilled only in the upper part of the sound absorbing pipe section. For this reason, the staying water in the sound-absorbing space does not enter the sound-absorbing pipe part, and conversely, the water present in the pipe of the sound-absorbing pipe part does not leak into the sound-absorbing space. Therefore, the problem of water backflow can be prevented.

  In the exhaust silencer, the exhaust introduction pipe passes through the front wall, the exhaust outlet is oriented in a direction in which the exhaust is directed toward the rear wall, and the exhaust passage is formed between the rear wall and the frame member. Preferably, the exhaust inlet is disposed in the vicinity of the front wall.

  According to this exhaust silencer, the exhaust outlet of the exhaust inlet pipe and the exhaust inlet of the exhaust outlet pipe can be kept away from each other in the noise reduction space, making it difficult to transmit the exhaust noise of the exhaust inlet pipe to the exhaust outlet pipe. it can. Further, since the exhaust gas is directed to the exhaust inlet through the rear passage portion, it is possible to prevent the occurrence of a short-circuit exhaust flow from the exhaust outlet to the exhaust inlet. Furthermore, since the exhaust passage becomes longer as much as it passes through the rear passage portion, it is possible to further enhance the silencing effect by the sound absorbing material through the small hole of the frame member.

  In the exhaust silencer, the exhaust lead-out pipe includes a first exhaust lead-out pipe and a second exhaust lead-out pipe each having an exhaust inlet, and the exhaust introduction pipe penetrates the front wall in the vicinity of the center in the vehicle width direction. The frame member includes a first frame member disposed between the exhaust introduction pipe and one side wall, and a second frame member disposed between the exhaust introduction pipe and the other side wall, The exhaust passage includes a central passage portion between the first frame member and the second frame member, a first side passage portion formed by the one side wall and a part of the first frame member, It is desirable to further include a second side passage portion formed by the other side wall and a part of the second frame member.

  According to this exhaust silencer, since the exhaust passage further includes the central passage portion, the first side passage portion, and the second side passage portion, the noise reduction effect by the sound absorbing material through the small hole of the frame member is further enhanced. be able to.

  In this case, it is preferable that a connection member for connecting the first frame member and the second frame member in the vicinity of the front wall is further provided, and the exhaust introduction pipe is supported by the connection member.

  According to this exhaust silencer, the rigidity of both frame members can be increased by connecting the first frame member and the second frame member. Further, the number of parts can be reduced by providing the connecting member with a function of supporting the exhaust introduction pipe. Furthermore, by using the frame pieces on the front side of the first and second frame members as members that also serve as the connecting members, the number of parts can be further reduced.

  In the exhaust silencer, the first exhaust lead-out pipe is supported by the first frame member, the second exhaust lead-out pipe is supported by the second frame member, and the first frame member and the second frame member are supported. It is desirable to further include a coupling member that couples at a position close to the rear wall at a lower position.

  According to this exhaust silencer, the exhaust introduction pipe, the first and second exhaust lead-out pipes, and the first and second frame members can be integrated with each other by the connecting member and the coupling member. For this reason, after assembling these components in advance, it becomes possible to attach to the silencer body, and the manufacturing efficiency can be increased.

  In the exhaust silencer described above, it is preferable that the exhaust outlet of the exhaust introduction pipe is further provided with a shielding plate that opens upward and surrounds the periphery of the exhaust outlet.

  According to this exhaust silencer, the shielding plate can prevent the exhaust once directed to the exhaust inlet from returning to the vicinity of the exhaust outlet and recirculating through the exhaust passage.

  According to the present invention, the noise of the air flow caused by the exhaust flow from the exhaust outlet of the exhaust inlet pipe to the exhaust inlet of the exhaust outlet pipe is also silenced while the sound absorbing material silences the exhaust noise of the exhaust inlet pipe and / or the exhaust outlet pipe. Can do. Therefore, it is possible to provide an engine exhaust silencer with improved noise reduction effect.

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 perspective view of the main silencer (exhaust silencer) according to the embodiment of the present invention with the upper plate removed. FIG. 3 is a perspective view of the main silencer with the perspective direction changed. FIG. 4 is a horizontal cross-sectional view of the main silencer. 5 is a cross-sectional view taken along line VV in FIG. 6 is a sectional view taken along line VI-VI in FIG. 7 is a cross-sectional perspective view taken along line VII-VII in FIG. 8 is a cross-sectional view taken along line VIII-VIII 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 constituting 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.

[Detailed structure of main silencer]
Hereinafter, the main silencer 2 will be described in detail. 2 is a perspective view of the main silencer 2 (with the upper plate 20A described later removed), FIG. 3 is a perspective view of the main silencer 2 with the perspective direction changed, and FIG. It is sectional drawing of a horizontal direction. 5, 6, 7 and 8 are sectional views taken along lines VV, VI-VI, VII-VII and VIII-VIII in FIG. 4, respectively (FIG. 7 is a sectional perspective view).

  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 housed in the silencer body 20. The sound absorbing chamber frame 5 (frame member) and the sound absorbing material 6 and the exhaust passage 7 provided in the silencer body 20 are provided. Hereinafter, each of these members will be described in detail.

<The silencer body>
The silencer body 20 is a housing having a wall portion that forms a silence 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 aligned in the left-right direction (vehicle width direction) as wall portions that define the silence space S. Side wall), and an upper wall 25 and a lower wall 26 arranged in the vertical direction (vehicle height direction). As shown in FIG. 4, the front wall 21 is a wall that linearly extends 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 relatively short walls that linearly extend 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. The distance between the right wall 23 and the left wall 24 is slightly narrower toward the rear. 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 flat housing in which the distance between the upper wall 25 and the lower wall 26 is considerably shorter than the distance between the front wall 21 and the rear wall 22 and the distance between the right wall 23 and the left wall 24. . Therefore, the upper wall 25 and the lower wall 26 are adjacent to the exhaust introduction pipe 3 and the first and second exhaust lead-out pipes 4A accommodated in the silencer body 20, as shown in FIGS. ing. As described above, the lower wall 26 of the silencer body 20 is gently inclined upward and rearward, and the rear wall 22 is formed by giving a larger inclination from the rear end of the lower wall 26. . For this reason, the wind can be peeled off at the rear end of the lower wall 26 and is not caught in the bumper face, so that the running resistance of the vehicle can be suppressed.

  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.

<Exhaust inlet pipe and exhaust outlet pipe>
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. In the present embodiment, a relatively short exhaust introduction pipe 3 is used. A relay pipe (not shown) is inserted into the upstream end 31 of the exhaust introduction pipe 3, and the upstream end of the relay pipe is connected to the downstream end of the exhaust pipe 13. The downstream end 32 of the exhaust introduction pipe 3 is the exhaust outlet A described above. The exhaust outlet A is oriented in the direction in which the exhaust discharged from the exhaust outlet A is directed to the rear wall 22.

  The exhaust introduction pipe 3 penetrates the front wall 21 near the center in the left-right direction (center position in the vehicle width direction). Since the exhaust introduction pipe 3 is short, the exhaust outlet A is located in the vicinity of the front wall 21. Referring to FIG. 6, the exhaust introduction pipe 3 is attached to the silencer body 20 so as to rise rearward so that the exhaust outlet A faces obliquely upward. The downstream end 32 of the exhaust introduction pipe 3 is not perpendicular to the pipe axis, but is an end face that is obliquely cut by a predetermined angle so that the lower side of the exhaust introduction pipe 3 becomes long. For this reason, the exhaust introduction pipe 3 is inserted into the front wall 21 toward the rear wall 22, but the exhaust outlet A opens toward the upper wall 25 (upward). The exhaust gas blown out from the exhaust outlet A blows against the upper wall 25 and then moves toward the rear wall 22.

  The exhaust inlet pipe 3 is tilted as described above and attached to the silencer main body 20 because moisture (condensed water) in the exhaust gas condensed in the silencer space S may stay on the lower wall 26 and stay there. This is to prevent water from flowing back to the exhaust introduction pipe 3 through the exhaust outlet A. Since the silencer body 20 of the present embodiment is a flat housing in the vertical direction, when the exhaust introduction pipe 3 is mounted horizontally, the distance between the lower side of the exhaust introduction pipe 3 and the lower wall 26 is reduced. In this case, the problem of the backflow may occur even if a little water stays on the lower wall 26. Therefore, the exhaust introduction pipe 3 is attached to the silencer main body 20 so as to rise rearward, and the downstream end 32 is obliquely cut so that the distance between the lower side of the exhaust introduction pipe 3 and the lower wall 26 is increased, whereby the reverse flow of the water Is preventing.

  The upstream end 31 of the exhaust introduction pipe 3 is supported so as to be sandwiched from above and below by a pair of pipe receiving portions 204 and 205 which are concave portions respectively provided in the center in the left-right direction of the front wall 21 of the upper plate 20A and the bottom plate 20B. Has been. Further, the vicinity of the center of the exhaust introduction pipe 3 in the pipe axis direction is supported by a connecting member 55 described later.

  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 downstream end of the first exhaust outlet pipe 4A passes through the right wall 23, and the downstream end of the second exhaust outlet pipe 4B passes through the left wall 24.

  Referring mainly to FIG. 4, each of the first and second exhaust outlet pipes 4A and 4B includes a first straight pipe 41, a second straight pipe 42, and a curved pipe 43 (sound absorbing pipe portion). The curved pipe 43 is a U-shaped curved pipe and includes an upstream end 431 on the upstream side of the exhaust flow and a downstream end 432 on the downstream side. The first straight tube 41 and the second straight tube 42 extend from both ends of the bending tube 43 in parallel in the left-right direction. That is, one end of the first straight tube 41 is connected to the upstream end 431 of the bending tube 43, and one end of the second straight tube 42 is connected to the downstream end 432.

  In the exhaust flows F1 and F2 in the first and second exhaust lead-out 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 tube 41 is disposed at a position relatively close to the front wall 21. 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.

  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 and a downstream end 412. The upstream end 411 is a pipe end portion provided with openings serving as the first and second exhaust inlets B1 and B2. 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 first and second exhaust inlets B1 and B2. The downstream end 412 is a tube end portion that is inserted into the upstream end 431 of the bending tube 43.

  The first and second exhaust inlets B <b> 1 and B <b> 2 are disposed near the front wall 21 and 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. On the other hand, the exhaust outlet A is disposed at the center position of the front wall 21 in the left-right direction. 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 421 of the second straight pipe 42 is inserted into the downstream end 432 of the bending pipe 43. The downstream end 422 of the second straight pipe 42 of the first exhaust outlet pipe 4A passes through the right wall 23 and is continuous with the first outlet opening C1. The first tail pipe 44A (FIG. 1) is connected to the penetrated downstream end. Further, the downstream end 422 of the second straight pipe 42 of the second exhaust outlet pipe 4B passes through the left wall 24 and continues to the second outlet opening C2. The 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.

  The second straight tube 42 is provided with a silencer. In a predetermined range in the tube axis direction of the second straight tube 42, a large number of small holes (not shown) are drilled over the entire circumference of the tube wall. A sound absorbing material 61 made of glass wool or the like is disposed so as to cover the entire circumference of the tube wall having the small holes. Further, a cylindrical sound absorbing material cover 44 capable of covering the sound absorbing material 61 is attached to the outer peripheral surface of the second straight tube 42.

  Referring mainly to FIGS. 4, 5, and 7, the curved pipe 43 (sound absorbing pipe portion) is a pipe that forms an exhaust path that is substantially circular in cross section and curved in a U shape. As will be described in detail later, the bending tube 43 is disposed in the sound absorbing chamber R defined by the sound absorbing chamber frame 5. 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 fitting part 433 of the outer peripheral side of U-shaped curve, and the inner flange part 434 of the inner peripheral side.

  The first half-cracked tube 43A has a semicircular cross-section bulging upward, has a U-shaped cavity in bottom view, and has an upper fitting piece 433A forming a fitting portion 433 on the outer peripheral side and an inner flange. The upper flange 434A that forms the upper side of the 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 fitting piece 433B that forms a fitting portion 433 on the outer peripheral side. A lower flange 434B that forms the lower side of the flange portion 434 is provided on the inner peripheral side. A large number of small holes 43H penetrating the tube wall are perforated on the upper surface which is the bulging top surface of the first half cracked tube 43A. On the other hand, such a small hole is not perforated in the second half cracked tube 43B.

  The upper fitting piece 433A and the lower fitting piece 433B are fitted together, and the upper flange 434A and the lower flange 434B are overlapped and joined together to form the bending tube 43. The fitting portion 433 has a structure in which the upper fitting piece 433A is fitted into the outer side of the lower fitting piece 433B from above. Thereby, when an article (sound-absorbing material 6) is inserted around the bending tube 43 from the upper surface side, it is difficult to cause the fitting portion 433 to be caught.

<Sound absorption room frame>
The sound absorbing chamber frame 5 is a frame member that partitions the sound absorbing chamber R filled with the sound absorbing material 6 in the sound deadening space S. The sound absorbing chamber frame 5 includes a first frame 5A (first frame member) disposed between the exhaust introduction pipe 3 and the right wall 23 (one side wall), an exhaust introduction pipe 3 and the left wall 24 (the other side). 2nd frame frame 5B (2nd frame member) arrange | positioned between these. The first and second frame frames 5A and 5B are rectangular frames that are long in the front-rear direction when viewed from above, and each include a front frame 51, a rear frame 52, an inner frame 53, and an outer frame 54. A rectangular space defined by the frames 51 to 54 is a sound absorption chamber R.

  Each of the frames 51 to 54 is a flat plate-like member extending between the upper wall 25 and the lower wall 26 of the silencer body 20. That is, the first and second frame frames 5 </ b> A and 5 </ b> B partition the space between the upper wall 25 and the lower wall 26, and create a space (sound absorbing chamber R) that is substantially closed by the sound deadening space S. The frames 51 to 54 are provided with a large number of small holes (51H, 52H, 53H, 54H) that allow the sound absorption chamber R and an exhaust passage 7 described later to communicate with each other on the wall surfaces. In FIG. 2 and FIG. 3, for the sake of easy viewing, small holes are drawn only in a part of the frames 51 to 54. However, as shown in FIG. Small holes are drilled in almost all areas of the wall surfaces 51 to 54.

  The front frame 51 is disposed close to the front wall 21 of the silencer body 20 and extends in the left-right direction substantially parallel to the front wall 21. A large number of small holes 51 </ b> H are formed in the wall surface of the front frame 51. In addition, a recess 511 is provided at the upper end edge of the front frame 51 to be fitted with the bead 203 of the upper wall 25. Further, a reinforcing portion 512 formed of a constriction recess extending in the left-right direction is provided near the center of the front frame 51 in the vertical direction.

  The rear frame 52 extends in the left-right direction in parallel to the front frame 51 at a position spaced apart from the rear wall 22 by a predetermined distance. A large number of small holes 52 </ b> H are formed in the wall surface of the rear frame 52. An upper flange portion 521 extending in the rearward direction is provided at the upper end edge of the rear frame 52, and a lower flange portion 522 extending in the rearward direction is provided at the lower end edge. The upper flange portion 521 is fixed to the upper wall 25 by, for example, plug welding, and the lower flange portion 522 is fixed to the lower wall 26 by, for example, spot welding. A recess 523 that fits with the bead 203 of the lower wall 26 is provided at the lower end edge of the rear frame 52.

  The inner frame 53 extends in the front-rear direction so as to connect inner end edges (end edges on the exhaust introduction pipe 3 side) of the front frame 51 and the rear frame 52. The inner frame 53 of the first frame 5A is adjacent to the right side of the exhaust introduction pipe 3, and the inner frame 53 of the second frame frame 5B is adjacent to the left side of the exhaust introduction pipe 3. A large number of small holes 53 </ b> H are formed in the wall surface of the inner frame 53.

  An upper flange portion 531 extending leftward (rightward) is provided at the upper end edge of the inner frame 53, and a lower flange portion 532 extending rightward (leftward) is provided at the lower end edge. The upper flange portion 531 is fixed to the upper wall 25 by, for example, plug welding, and the lower flange portion 532 is fixed to the lower wall 26, for example, by spot welding. Further, at the front end and the rear end of the inner frame 53, horizontal flange portions 533 that are respectively joined to the front frame 51 and the rear frame 52 are provided.

  The outer frame 54 extends in the front-rear direction so as to connect the outer edges of the front frame 51 and the rear frame 52. The outer frame 54 of the first frame 5A is at a position spaced apart from the right wall 23, and the outer frame 54 of the second frame 5B is located at a position spaced apart from the left wall 24, Each is arranged. A large number of small holes 54 </ b> H are formed in the wall surface of the outer frame 54.

  An upper flange portion 541 extending in the right direction (left direction) is provided at the upper end edge of the outer frame 54, and a lower flange portion 542 (FIG. 7) extending in the left direction (right direction) is provided at the lower end edge. The upper flange portion 541 is fixed to the upper wall 25 by, for example, plug welding, and the lower flange portion 542 is fixed to the lower wall 26, for example, by spot welding. Further, at the front end and the rear end of the outer frame 54, joint portions for the front frame 51 and the rear frame 52 are provided.

  Further, the outer frame 54 includes two through holes, and has a burring portion 543 formed on the periphery of these through holes. As shown in FIG. 4, the two through holes are drilled in alignment with the upstream end 431 and the downstream end 432 of the bending tube 43. The two burring portions 543 support the upstream end 431 into which the first straight pipe 41 is inserted and the downstream end 432 into which the second straight pipe 42 is inserted. Thus, the first exhaust lead-out pipe 4A is supported by the first frame 5A, and the second exhaust lead-out pipe 4B is supported by the second frame frame 5B.

  As schematically shown in FIG. 2, the sound absorbing chamber R partitioned by the frames 51 to 54 is filled with a sound absorbing material 6. As the sound absorbing material 6, for example, a glass wool bag in which glass wool is packed in a bag can be used. The sound absorbing material 6 is filled in the sound absorbing chamber R so as to fill almost the entire area of the sound absorbing chamber R in the upper, lower, left, and right sides. In FIG. 2, the sound absorbing material 6 filled in each sound absorbing chamber R is drawn like a single glass wool bag, but a plurality of small glass wool bags may be filled in each sound absorbing chamber R. good.

  The first exhaust lead-out pipe 4A is piped in the sound deadening space S so as to have a sound absorption pipe section that passes through the sound absorption chamber R defined by the first frame 5A. Further, the second exhaust lead-out pipe 4B is piped in the sound deadening space S so as to have a sound absorption pipe section that passes through the sound absorption chamber R defined by the second frame 5B. In the present embodiment, the sound absorbing pipe portion is the curved pipe 43 in both the first and second exhaust outlet pipes 4A and 4B. That is, the bending tube 43 is disposed in the sound absorption chamber R. Accordingly, the periphery of the bending tube 43 is surrounded by the sound absorbing material 6.

  As described above, the bending tube 43 has a large number of small holes 43H. The small hole 43H allows the inside of the bending tube 43 and the sound absorption chamber R to communicate with each other. Therefore, when airflow sound (exhaust noise) is generated in the exhaust gas passing through the curved tube 43, the airflow sound is released to the sound absorbing chamber R through the small holes 43H and is absorbed by the sound absorbing material 6. Here, the small hole 43H is drilled only in the bulging top portion of the first half cracked tube 43A located on the upper side of the bending tube 43. That is, in a state where the bending tube 43 is installed in the sound absorbing chamber R, the small hole 43H is drilled only in a portion corresponding to the upper region of the sound absorbing chamber R. This is to prevent water that may stay on the lower wall 26 of the silencer body 20 from entering the bending tube 43.

<Accessory of sound absorption room frame>
The silencer body 20 is provided with a connecting member 55 and a connecting member 56 as accessories of the sound absorbing chamber frame 5. The connecting member 55 is a plate-like member that connects the first frame frame 5 </ b> A and the second frame frame 5 </ b> B in the vicinity of the front wall 21 of the silencer body 20. Specifically, the connecting member 55 is erected between the front frame 51 of the first frame 5A and the front frame 51 of the second frame 5B, that is, at a position where the exhaust introduction pipe 3 is inserted. Yes. The connecting member 55 connects the left and right front frames 51 in the left-right direction and supports the exhaust introduction pipe 3.

  In the present embodiment, an example is shown in which the left and right front frames 51 and the connecting member 55 are formed of an integral plate member. That is, the integrated plate-like member has a left and right length extending from the right outer frame 54 to the left outer frame 54, the central portion thereof is the connecting member 55, and the right portion is the front frame 51 of the first frame 5A. The left portion serves as the front frame 51 of the second frame 5B. Of course, the connecting member 55 may be a separate member from the left and right front frames 51.

  The connecting member 55 includes a support hole 55H, an upper flange portion 551, and a shielding plate 552. The support hole 55H is a hole for penetrating the exhaust introduction pipe 3 and supporting it. As shown in FIG. 6, the support hole 55 </ b> H is a hole subjected to burring, and supports the vicinity of the center of the exhaust introduction pipe 3 in the front-rear direction. The upper flange portion 551 is a flange portion to which the connecting member 55 is joined and fixed to the upper wall 25 (FIG. 8). The lower end edge of the connecting member 55 is in contact with the lower wall 26 (FIG. 7).

  The shielding plate 552 is a plate portion located between the main body portion of the connecting member 55 and the upper flange portion 551. As shown in FIGS. 6 and 7, the shielding plate 552 extends obliquely upward and rearward from the upper end of the main body portion of the connecting member 55 and covers the exhaust outlet A of the exhaust introduction pipe 3 from above. Since the upper flange portion 551 connected to the rear end of the connecting member 55 is joined to the upper wall 25, the shielding plate 552 has a space above the exhaust outlet A and a space on the front side of the connecting member 55 (front frame 51). Serves as a barrier to block. The shielding plate 552 can block the exhaust flow that attempts to return to the exhaust outlet A through the passage between the front frame 51 and the front wall 21. In the vicinity of the front end of the inner frame 53, a flat plate portion 53F in which the small holes 53H are not drilled is provided. For this reason, the upper side of the exhaust outlet A is surrounded by the shielding plate 552 and the left and right sides are surrounded by the flat plate portion 53F, so that the effect of blocking the exhaust flow is further enhanced.

  The coupling member 56 is a member that couples the first frame frame 5 </ b> A and the second frame frame 5 </ b> B at positions below the both in a portion close to the rear wall 22. The coupling member 56 connects the vicinity of the lower ends of the left and right inner frames 53 at a position near the rear wall 22. The coupling member 56 is disposed so as to contact the lower wall 26 (FIG. 6). This is to prevent the coupling member 56 from resisting the exhaust flow discharged from the exhaust outlet A.

  The first frame 5A and the second frame 5B are connected and integrated in the vicinity of the front side by the connecting member 55 and in the vicinity of the rear side by the connecting member 56, respectively. The exhaust introduction pipe 3 is supported by a connecting member 55, and the first and second exhaust lead-out pipes 4A and 4B are supported by first and second frame frames 5A and 5B. Therefore, the exhaust introduction pipe 3, the first and second exhaust lead-out pipes 4A and 4B, and the first and second frame frames 5A and 5B can be integrated with the connecting member 55 and the coupling member 56. For this reason, it becomes possible to attach these components to the silencer main body 20 after assembling in advance, and to improve manufacturing efficiency.

<Exhaust passage>
The exhaust passage 7 is a silence space formed by the wall portion of the silencer body 20 and the first and second frame frames 5A and 5B between the exhaust outlet A and the first and second exhaust inlets B1 and B2. This is an exhaust passage in S. Most of the exhaust discharged from the exhaust outlet A passes through the exhaust passage 7 and reaches the first and second exhaust inlets B1 and B2. Referring mainly to FIG. 4, the exhaust passage 7 includes a central passage 71 (a central passage portion), a rear passage 72 (a rear passage portion), a right side passage 73A (a first side passage portion), and a left side passage 73B ( Second side passage portion).

  The central passage 71 is a passage formed between the first and second frame frames 5A and 5B. Specifically, the central passage 71 is a passage formed between the left and right inner frames 53 facing each other with the exhaust introduction pipe 3 interposed therebetween and extending in the front-rear direction. The rear passage 72 is a passage formed between the rear wall 22 of the silencer body 20 and the left and right rear frames 52 (part of the frame member) and extending in the left-right direction. Both passages 71 and 72 intersect in a T shape so that the downstream end of the central passage 71 joins the center of the rear passage 72 in the left-right direction.

  The right side passage 73A is a passage formed between the right wall 23 and the outer frame 54 (a part of the first frame member) of the first frame 5A and extending in the front-rear direction. The left side passage 73B is a passage formed between the left wall 24 and the outer frame 54 (a part of the second frame member) of the second frame 5B and extending in the front-rear direction. The upstream end of the right side passage 73A is connected to the right downstream end of the rear passage 72, and the upstream end of the left side passage 73B is connected to the left downstream end of the rear passage 72. On the other hand, a first exhaust inlet B1 is opened near the downstream end of the right side passage 73A, and a second exhaust inlet B2 is opened near the downstream end of the left side passage 73B.

  Exhaust gas discharged from the exhaust outlet A blows against the upper wall 25 (FIG. 6), but is guided by the central passage 71 to form an exhaust flow F toward the rear wall 22. Thereafter, the exhaust flow F is divided into a first exhaust flow F1 directed to the right and a second exhaust flow F2 directed to the left by being blown against the rear wall 22. The first exhaust flow F <b> 1 passes through the right half of the rear passage 72 and travels toward the right wall 23. The first exhaust flow F1 smoothly enters the right side passage 73A in combination with the round shape at the corner where the rear wall 22 and the right wall 23 intersect. Thereafter, the first exhaust flow F1 advances forward in the right side passage 73A and reaches the first exhaust inlet B1. Similarly, the second exhaust flow F2 passes through the left half of the rear passage 72 toward the left wall 24 and enters the left side passage 73B. Then, the second exhaust flow F2 advances forward in the left side passage 73B and reaches the second exhaust inlet B2. Thereafter, the exhaust gas passes through the first and second exhaust outlet pipes 4A and 4B and is discharged to the outside from the first and second outlet openings C1 and C2, respectively.

[Effects]
According to the main silencer 2 described above, the following operational effects are obtained. First, the first and second exhaust exhaust pipes 4 </ b> A and 4 </ b> B have a curved pipe 43 that is a sound absorbing pipe portion that passes through a sound absorbing chamber R filled with the sound absorbing material 6. For this reason, even if an airflow sound is generated in the first and second exhaust flows F1 and F2 passing through the bending tube 43, the airflow sound is absorbed by the sound absorbing material 6, so that a silencing effect can be obtained.

  Further, the exhaust passage 7 through which the first and second exhaust flows F1 and F2 flow from the exhaust outlet A to the first and second exhaust inlets B1 and B2, that is, the central passage 71, the rear passage 72, and the right side passage 73A. The rear frame 52, the inner frame 53, the outer frame 54, and the front frame 51 that define the left-side passage 73B are connected to the sound absorption chamber R and the exhaust passage 7 through substantially the entire area of the respective wall surfaces. Small holes 52H, 53H, 54H, 51H are perforated. For this reason, even if airflow noise is generated in the first and second exhaust flows F1 and F2 passing through the exhaust passage 7, the sound is absorbed by the sound absorbing material 6 in the sound absorbing chamber R through the small holes 51H to 54H. Therefore, it is possible to mute the airflow sound caused by the exhaust flow from the exhaust outlet A toward the first and second exhaust inlets B1 and B2.

  The silencer body 20 has a flat shape in which the upper wall 25 and the lower wall 26 are adjacent to the exhaust introduction pipe 3 and the first and second exhaust lead-out pipes 4A and 4B, respectively. The first and second frame frames 5 </ b> A and 5 </ b> B are formed by frames 51 to 54 extending between the upper wall 25 and the lower wall 26. Therefore, the exhaust can be guided from the exhaust outlet A to the first and second exhaust inlets B1 and B2 without leaking the exhaust passage 7 so much. Therefore, the sound absorbing effect of the sound absorbing material 6 through the small holes 51H to 54H can be surely enjoyed. In addition to this, the vertical rigidity of the silencer body 20 having a flat shape can be increased by the first and second frame frames 5A and 5B that define the sound absorption chamber R.

  The curved tube 43 has a small hole 43H only in the upper surface portion corresponding to the upper region of the sound absorbing chamber R. On the other hand, the small holes 51H to 54H of the first and second frame frames 5A and 5B are perforated in substantially the entire upper and lower regions of the frames 51 to 54, and the sound absorbing material 6 is disposed in the entire region of the sound absorbing chamber R. Filled. For this reason, even if the water generated by the combustion in the engine 1 stays in the lower wall 26 of the silencer body 20, the staying water does not enter the curved pipe 43. Conversely, the water present in the tube of the curved tube 43 does not leak into the silencing space S. Therefore, the problem of water backflow can be prevented. On the other hand, since the small holes 51H to 54H are perforated by making full use of the vertical width of the frames 51 to 54, the sound of the airflows of the first and second exhaust flows F1 and F2 can be satisfactorily taken into the sound absorption chamber R. Can do.

  The exhaust outlet A is disposed in the vicinity of the front wall 21, the first and second exhaust inlets B1 and B2 are disposed in the vicinity of the front wall 21 and in the vicinity of the right wall 23 and the left wall 24, and the exhaust passage is a central passage. 71, a large passage including a rear passage 72, a right side passage 73A and a left side passage 73B. For this reason, the exhaust outlet A and the first and second exhaust inlets B1 and B2 are kept away from each other in the flow path of the first and second exhaust flows F1 and F2, and the exhaust noise of the exhaust introduction pipe 3 is reduced to the first and second. 2 It is possible to make it difficult to transmit to the exhaust exhaust pipes 4A and 4B. Further, since the exhaust gas is directed to the first and second exhaust inlets B1 and B2 via the rear passage 72, occurrence of a short-circuited exhaust flow to the exhaust outlet A and the first and second exhaust inlets B1 and B2 is prevented. can do. Furthermore, since the exhaust passage 7 becomes longer as much as it passes through the rear passage 72, the noise reduction effect by the sound absorbing material 6 through the small holes 51H to 54H of the first and second frame frames 5A and 5B can be further enhanced.

  The main silencer 2 includes a connecting member 55 that connects the first frame frame 5A and the second frame frame 5B in the vicinity of the front wall 21 of the silencer body 20. The exhaust introduction pipe 3 is supported by the connecting member 3. Thus, by connecting the first and second frame frames 5A and 5B, the support rigidity of both frame frames can be increased. Moreover, the number of parts can be reduced by providing the connecting member 55 with a function of supporting the exhaust introduction pipe 3. Furthermore, the front frame 51 of the first and second frame frames 5A and 5B can be integrated with the connecting member 55, thereby contributing to further reduction in the number of parts.

  Further, the main silencer 2 includes a shielding plate 552 that surrounds the exhaust outlet A. By this shielding plate 552, it is possible to prevent the exhaust once directed to the first and second exhaust inlets B1 and B2 via the exhaust passage 7 from returning to the vicinity of the exhaust outlet A and recirculating through the exhaust passage 7. . That is, an increase in exhaust pressure can be suppressed.

[Description of Modified Embodiment]
As mentioned above, although embodiment of this invention was described, this invention is not limited to this, The various deformation | transformation embodiment as shown below can be taken.

  (1) In the above-described embodiment, an example in which the curved pipe 43 constituting a part of the first and second exhaust outlet pipes 4A and 4B is a sound absorbing pipe portion passing through the sound absorbing chamber R has been described. The sound absorbing pipe section may be another pipe section of the first and second exhaust outlet pipes 4A and 4B, that is, the first straight pipe 41 or the second straight pipe 42. Alternatively, a part of the exhaust introduction pipe 3 may be used as a sound absorbing pipe part.

  (2) In the above embodiment, 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 and 4B are the first, The example provided with the 2nd straight tubes 41 and 42 and the bending tube 43 was shown. 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. Alternatively, the first and second exhaust lead-out pipes 4A, 4B or the exhaust introduction pipe 3 may not include the curved pipe 43.

  (3) The small holes 51H to 54H of the first and second frame frames 5A and 5B may be formed in a part of the frames 51 to 54, rather than the entire upper and lower regions. Moreover, if the problem of the backflow of water does not arise, it is good also as an aspect which perforates the small hole 43H in the perimeter of the bending tube 43. FIG.

1 Engine 10 Exhaust device 2 Main silencer (Exhaust silencer)
20 Silencer body 21 Front wall 21
22 Rear wall 22
23 Right wall 23 (side wall)
24 Left wall 24 (side wall)
25 Upper wall 25
26 Lower wall 26
3 Exhaust lead pipe 4A First exhaust lead pipe 4B Second exhaust lead pipe 43 Curved pipe (sound absorbing pipe section)
43H small hole 5 sound absorbing chamber frame 5A first frame frame 5B second frame frame 55 connecting member 552 shielding plate 56 coupling member 6 sound absorbing material 7 exhaust passage 7
71 Central passage (Central passage part)
72 Rear passage (rear passage part)
73A Right side passage (first side passage part)
73B Left side passage (second side passage part)
S Silencing space R Sound absorption chamber A Exhaust outlet B1 First exhaust inlet B2 Second exhaust inlet

Claims (4)

A silencer body having a wall part that forms a silencing space into which exhaust of the engine of the vehicle is introduced;
A sound absorbing material,
A frame member defining a sound absorbing chamber filled with the sound absorbing material in the sound deadening space;
An exhaust introduction pipe having an exhaust outlet and introducing the exhaust into the silencing space;
An exhaust outlet pipe that has an exhaust inlet and discharges the exhaust from the silencing space to the outside;
An exhaust passage formed by the wall of the silencer body and the frame member between the exhaust outlet and the exhaust inlet;
At least one of the exhaust introduction pipe or the exhaust lead-out pipe has a sound absorption pipe portion passing through the sound absorption chamber,
The frame member has a large number of small holes for communicating the sound absorption chamber and the exhaust passage,
The wall portion of the silencer body includes a front wall and a rear wall arranged in the vehicle longitudinal direction, a pair of side walls arranged in the vehicle width direction, and an upper wall and a lower wall arranged in the vehicle vertical direction,
The silencer body has a flat shape in which the upper wall and the lower wall are adjacent to the exhaust inlet pipe and the exhaust outlet pipe, respectively.
The frame member extends between the upper wall and the lower wall;
The exhaust introduction pipe passes through the front wall, and the exhaust outlet is oriented in a direction in which the exhaust is directed to the rear wall;
The exhaust passage includes a rear passage portion formed by the rear wall and a part of the frame member,
The exhaust inlet is disposed in the vicinity of the front wall;
The exhaust outlet pipe includes a first exhaust outlet pipe and a second exhaust outlet pipe each having an exhaust inlet,
The exhaust introduction pipe passes through the front wall near the center in the vehicle width direction,
The frame member includes a first frame member disposed between the exhaust introduction pipe and one side wall, and a second frame member disposed between the exhaust introduction pipe and the other side wall,
The exhaust passage includes a central passage portion between the first frame member and the second frame member, a first side passage portion formed by the one side wall and a part of the first frame member, An exhaust silencer for an engine, further comprising: a second side passage portion formed by the other side wall and a part of the second frame member. The engine exhaust silencer according to claim 1 ,
A connecting member that connects the first frame member and the second frame member in the vicinity of the front wall;
The exhaust exhaust pipe of the engine is supported by the connecting member. The engine exhaust silencer according to claim 2 ,
The first exhaust lead-out pipe is supported by the first frame member, the second exhaust lead-out pipe is supported by the second frame member,
An exhaust silencer for an engine, further comprising a coupling member that couples the first frame member and the second frame member at a lower position in a portion close to the rear wall. The engine exhaust silencer according to any one of claims 1 to 3 ,
The exhaust outlet of the exhaust introduction pipe opens upward,
An exhaust exhaust silencer for an engine, further comprising a shielding plate surrounding the exhaust outlet.

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