TWI647382B - Exhaust device of straddle type vehicle - Google Patents

Abstract

Even if the exhaust pipe with a catalyst-built pipe at the downstream end of the exhaust pipe has an inclination angle ｣with respect to the vehicle's front-back direction when viewed from the top of the vehicle, the exhaust pipe can be suppressed from｢ and exhaust. The sharp bend near the upstream of the connection between the mufflers does not sacrifice the capacity of the expansion chamber of the exhaust muffler. An exhaust pipe (50) with an upstream end connected to the internal combustion engine (3) and an extended catalyst inner pipe (60) connected to the downstream end (50b) of the exhaust pipe connected to the ｢are provided. An exhaust muffler pipe (70) and an exhaust device of a straddle-type vehicle having an expansion chamber (90) in the exhaust muffler pipe are connected to an exhaust muffler pipe provided with a catalyst-integrated pipe and directed toward the front side of the vehicle The connecting surface (74A) is arranged to extend in the left-right direction (yy) of the vehicle, and the catalyst internal tube connected to the exhaust pipe has an inclined angle (θ) with respect to the vehicle front-rear direction (xx) in a plan view of the vehicle. The ground is connected to the connection surface, and at a position where the tube inside the catalyst is connected to the connection surface, a part of the tube inside the catalyst is arranged to enter the expansion chamber.

Description

Exhaust device of straddle type vehicle

[0001] The present invention relates to an exhaust device of a straddle-type vehicle including a catalyst-built-in pipe at the downstream ends of an exhaust pipe and an exhaust muffler pipe.

[0002] A technique of disposing a partition wall in an internal space of an exhaust muffler and dividing the internal space into a plurality of expansion chambers is described in, for example, Patent Document 1 below. In the exhaust muffler shown in Patent Document 1, an exhaust pipe that introduces exhaust gas from an internal combustion engine into the exhaust muffler, a connection surface of the exhaust muffler extending in the left-right direction of the vehicle, and a In the plan view, the entirety of the catalyst-integrated tube, which is connected vertically to the downstream end of the exhaust pipe, is housed inside the exhaust muffler. In order to satisfy the muffling function of the exhaust muffler, it is necessary to ensure the capacity of the expansion chamber. In the technology shown in Patent Document 1, the volume occupied by the catalyst tube inside the exhaust muffler increases, and there is a need to ensure expansion. The issue of room capacity. In addition, Patent Document 2 below discloses a technology of "exhaust pipe, which connects the exhaust muffler pipe to the left and right direction of the vehicle, and is connected vertically from the front in the vehicle's top view." The tube is offset in the vehicle width direction to form a sharp bend and is connected to the connection surface of the exhaust muffler tube. It is expected that the exhaust pipe is vertically connected to the connection surface of the exhaust muffler. Therefore, if the shape of the exhaust pipe that is bent sharply is used, there will be a problem of "influencing output". In addition, when the downstream end portion of the exhaust pipe has to be bent to the front-rear direction of the vehicle due to the arrangement of the vehicle, if the connection surface of the exhaust muffler pipe is made perpendicular to the exhaust pipe, the exhaust muffler pipe The connecting surface will be inclined with respect to the left and right directions of the vehicle and back, which will cause the capacity of the expansion chamber to decrease. [Prior Art Documents] [Patent Documents] [0003] Patent Document 1: Japanese Patent No. 5468921 (Figure 1, Figure 3, Figure 5, and Figure 7) Patent Document 2: Japanese Patent Application Laid-Open No. 2014-234750 Bulletin (Figures 1 to 3)

[Problems to be Solved by the Invention] [0004] The present invention is an invention developed in view of the above-mentioned conventional technology, and an object of the present invention is to provide an exhaust device having a catalyst-integrated pipe at a downstream end of the exhaust pipe. In addition, even if the exhaust pipe has an inclined angle with respect to the front-rear direction of the vehicle in a plan view of the vehicle due to a limitation of the vehicle configuration, the exhaust pipe can be suppressed from being "upstream of the connection portion with the exhaust muffler pipe." The "exhaust" of the straddle-type vehicle which sacrifice the capacity of the expansion chamber of the exhaust muffler can be avoided. [Means for Solving the Problem] [0005] In order to achieve the above-mentioned object, the exhaust device of the straddle-type vehicle of the present invention includes a power unit including an internal combustion engine mounted on the straddle-type vehicle and has an "upstream end connected to the aforementioned internal combustion engine, An exhaust pipe constituting an exhaust gas path for exhausting exhaust gas ", and an exhaust muffler pipe connected to" a downstream end of the exhaust pipe connected to a catalyst built-in pipe extending in its extending direction ", and The exhaust device of a straddle-type vehicle having an expansion chamber provided in the internal space of the exhaust muffler. The exhaust muffler has an outer shell composed of a plurality of structural surfaces, and is connected to the catalyst inner tube and faces the exhaust pipe. The aforementioned structural surface in front of the vehicle is arranged as a connecting surface extending in the left-right direction of the vehicle and the catalyst-integrated tube connected to the exhaust pipe is inclined at an angle with respect to the front-rear direction of the vehicle in a plan view of the vehicle. The ground is connected to the connecting surface, and at a position where the tube inside the catalyst is connected to the connection surface, a part of the tube inside the catalyst is arranged to enter the expansion chamber. According to the foregoing configuration, due to the limitation of the arrangement of the vehicle, the exhaust pipe has an inclined angle with respect to the front-rear direction of the vehicle in a top view of the vehicle, and the exhaust pipe is connected to the "exhaust muffler arranged to extend in the left-right direction of the vehicle" In the case of a connecting surface, the catalyst built-in pipe connected to the "extending direction of the downstream end of the exhaust pipe" protrudes from the connecting surface to the upstream side, and a part is arranged to enter the expansion chamber, and the vehicle is viewed from a plan view. The middle is connected to the connection surface at an oblique angle with respect to the front-rear direction of the vehicle, and it is possible to suppress the sharp bending of the exhaust pipe near the upstream of the catalyst-built pipe. In addition, since the inclination angle with respect to the exhaust pipe is formed perpendicularly, the front face of the housing of the exhaust muffler pipe, that is, the connection surface is inclined with respect to the left and right directions of the vehicle and backed up, it is possible to avoid sacrificing the expansion chamber of the exhaust muffler pipe. Capacity. [0006] In the aforementioned structure, the internal combustion engine is a multi-cylinder internal combustion engine in which a plurality of cylinders are arranged in the left-right direction of the vehicle, and the exhaust pipe has a confluence section where the exhaust pipes of the plurality of cylinders converge. The downstream end of the catalyst is connected to the catalyst inner tube in the same direction as the downstream end. In a vehicle top view, the catalyst inner tube may also be extended at an inclined angle with respect to the front-rear direction of the vehicle. According to this structure, since the merging portion of the exhaust pipe is connected to the catalyst internal pipe, and it is provided at an inclined angle in the "same direction as the downstream end of the merging portion", the pipe is provided in the exhaust pipe and the catalyst internal pipe. The connection portion between them will not be bent. As a result, the exhaust gas can be flowed to all the catalysts provided in the tubes inside the catalyst without biasing, and the purification performance can be fully exerted. [0007] In the aforementioned structure, the outer shell of the exhaust muffler is formed by welding the left and right divided bodies, and the catalyst is provided with a tube inside the connecting surface so that its center axis is in the vehicle ’s top view. The joints of the left and right divided bodies are formed uniformly, and are integrated with the exhaust muffler by being sandwiched and welded by the left and right divided bodies. The joints of the left and right divided bodies are along the front and rear of the vehicle. It is formed in a direction, and the end edge of the catalyst built-in tube is sandwiched to form a tube joint part which protrudes obliquely outward along the surface of the catalyst built-in tube toward the center axis direction of the catalyst built-in tube. According to this structure, since the housing of the exhaust muffler pipe is formed by the left and right divided bodies, the central axis of the tube provided in the catalyst is aligned with the joint portion of the left and right divided bodies at the connecting plane on the connection surface. The left and right divided bodies are sandwiched with the catalyst internal tube and welded together, so that the exhaust muffler pipe and the catalyst internally integrated tube are integrated, and the joint of the divided body is further along the front and rear directions of the vehicle, and the catalyst is sandwiched. The end edges of the left and right divisions of the built-in tube are formed at the pipe joint portion “protruding obliquely outward along the surface of the catalyst-installed tube toward the center axis of the catalyst-built tube”. There is a tube in the medium, and the welding bonding line of the left split body and the welding bonding line of the right split body are arranged in equal (equal division) to achieve: the bonding strength between the left and right parts of the catalyst internal tube and the exhaust muffler Of equilibrium. [0008] In the foregoing structure, the catalyst internal tube may also have a circular cross section, formed on the connection surface of the exhaust muffler tube, and the connection port connected to the catalyst internal tube is formed in an oval shape, and It is welded to the outer peripheral surface of the tube provided in the catalyst. According to this structure, since "the connection port provided on the connection surface of the exhaust muffler pipe and connected to the catalyst internal tube having a circular cross section" is formed in an oval shape, the connection port and the outer periphery of the tube internal to the catalyst are formed. Increasing the welding length between faces can improve the joint rigidity. [0009] In the aforementioned structure, the aforementioned exhaust muffler may also have an upper and lower partition wall that divides the expansion chamber into upper and lower parts in a side view of the vehicle, above the catalyst-installed pipe. According to this structure, in the case where a plurality of expansion chambers in the exhaust muffler pipe are configured, the expansion chambers can be divided into upper and lower portions so as not to interfere with the catalyst-installed tubes, and a part of the catalyst-installed tubes can be accommodated and arranged. In one expansion chamber and form another expansion chamber. [0010] In the above-mentioned structure, the above-mentioned upper and lower partition walls may be formed in such a manner that an end portion on a side of a tube provided in the catalyst is bent toward an upper portion of the tube provided in the catalyst. According to this structure, since the end on the catalyst-integrated tube side of the upper and lower partition walls is bent upward, the distance between the catalyst-integrated tube and the upper and lower partition walls is increased, and it is possible to suppress the catalyst-integrated tube from separating the upper and lower parts. The thermal influence of the partition wall and the thermal expansion deformation of the upper and lower partition walls are suppressed. [0011] In the foregoing structure, may also be provided with a tube in the catalyst, connected to a discharge duct on its downstream side, and the discharge duct may be extended along the upper and lower partition walls in a vehicle side view. According to this structure, since the exhaust duct extends along the upper and lower partition walls below the upper and lower partition walls, it is possible to prevent the interference between the exhaust duct and the upper and lower partition walls and increase the length of the exhaust duct. [0012] In the foregoing structure, the exhaust muffler may further include a front and rear partition wall that divides the expansion chamber into front and rear sides, and the front and rear partition walls are inclined such that the lower part is farther away from the catalyst inner tube than the upper part. According to this structure, the exhaust muffler has a front and rear partition wall that divides the expansion chamber into front and rear sides, and has an upper and lower partition wall that divides the expansion chamber into upper and lower positions in the vehicle side view above the catalyst-installed tube. Therefore, the upper part of the front and rear partition walls is closer to the catalyst inner tube than the lower part, and the lower part is inclined toward the "side away from the catalyst inner tube" than the upper part. Therefore, it can be more ensured from the installation of the tube in the catalyst to the front and rear partition walls. Distance to reduce the outflow resistance of the exhaust gas from the catalyst tube and improve the exhaust gas exhaust efficiency. [Effects of the Invention] 001 [0013] According to the exhaust device of the straddle-type vehicle of the present invention, due to the configuration limitation of the vehicle, the exhaust pipe has an inclined angle with respect to the front-rear direction of the vehicle in a plan view of the vehicle, and exhausts the exhaust gas. When the pipe is connected to the connection surface of the "exhaust muffler pipe arranged to extend in the left-right direction of the vehicle", the catalyst internal pipe connected to the "extend direction of the downstream end of the exhaust pipe" is connected from the connection surface to the upstream side. It protrudes and is partially arranged to extend into the expansion chamber. By being connected to the connection surface at an oblique angle with respect to the front-back direction of the vehicle in a plan view of the vehicle, it is possible to suppress a sharp bend of the exhaust pipe near the upstream of the catalyst-installed pipe. In addition, since the inclination angle with respect to the exhaust pipe is formed perpendicularly, the front face of the housing of the exhaust muffler pipe, that is, the connection surface is inclined with respect to the left and right directions of the vehicle and backed up, so that the expansion chamber of the exhaust muffler pipe can be avoided Capacity.

[0015] An exhaust device of a straddle-type vehicle according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 6.方向 The directions such as front, back, left, right, up, down, etc. described in this specification and the scope of patent application are the directions of the straddle-type vehicle that are mounted on the exhaust device of the straddle-type vehicle of this embodiment. In this embodiment, the straddle type vehicle is a locomotive. In addition, the arrow FR in the figure indicates the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates above the vehicle. In the drawing, the small black arrow is a symbol that schematically shows the flow of exhaust gas. The second embodiment described in FIGS. 7 to 10 is also the same as the above-mentioned description of each point in FIG. 1. [0016] FIG. 1 is a right side view of a locomotive 1 according to an embodiment of the invention. As shown in FIG. 1, the vehicle body frame 2 of the locomotive 1 includes a head pipe 20 that supports a “fork 11 that supports the front wheel 10 pivotably” so as to be steerable; Frame 21; a single engine hanger 22 extending from the head pipe 20 to the lower rear at a more acute angle than the main frame 21; right and left paired left and right pivot frames 23 extending from the rear of the main frame 21 downward; from the main frame The seat cushion rail 24 extends rearward and upward at the rear portion of 21, and the main frame 21 and the pivot support frame 23 are integrated into one body. [0017] A power unit 4 is supported at a rear portion of the main frame 21 of the vehicle body frame 2, a lower portion of the engine hanger 22, and a lower portion of the pivot support frame 23. The power unit 4 includes an internal combustion engine 3 disposed below the main frame 21. . The internal combustion engine 3 is a 4-stroke internal combustion engine (engine) in which four cylinders are arranged in a line with four cylinders in the vehicle width direction. The cylinder axis is tilted forward and is formed at the cylinder block 32 at the upper end of the front portion 70a of the crank case 31; the cylinder head 33 fastened to the upper end of the cylinder block 32; and the head cover 34 fastened to the upper end of the cylinder head 33. The lower part is assembled with an oil receiving pan 35. [0018] In addition, the front end portion of the rocker arm 13 which pivotally supports the "rear wheel 12 driven by the power generated by the internal combustion engine 3" at the rear end portion is supported by the lower portion of the pivot support frame 23 in a swingable manner. Above the internal combustion engine 3, a fuel tank 14 is mounted on the main frame 21, and a seating seat 15 disposed behind the fuel tank 14 is supported by a seat rail 24. [0019] The head pipe 20 is covered by the front cover 16 from the front, the front lower portion of the fuel tank 14 and the front portion 70a of the vehicle body frame 2 are covered by the left and right front side covers 17 from both sides, and the fuel tank The lower portion of the rear portion 14 and the rear portion of the vehicle body frame 2 are covered by left and right rear side covers 18 arranged below the seating seat 15 from both sides. [0020] The exhaust device 5 according to this embodiment includes an exhaust pipe 50 which is connected to the upstream end 50a by the four exhaust ports 33a on the front side of the cylinder head 33 and constitutes an exhaust gas for deriving exhaust gas. Four primary exhaust pipes ("exhaust pipes" in the present invention) 50A "and" one collective exhaust pipe (commonly connected to the downstream ends of the four primary exhaust pipes 50A) (in the present invention "Exhaust pipe" "confluence unit") 50B "; and the catalyst built-in pipe 60, connected to the extension of the downstream end 50b of the collection exhaust pipe 50B extension direction; and an exhaust muffler pipe 70, connected to the contact MEDIA 内 管管 60. [0021] In the locomotive 1 of the present embodiment, since the internal combustion engine 3 is arranged horizontally with the crankshaft 31 pointing in the vehicle width direction, referring to FIG. 2 together, four primary exhaust pipes 50A correspond to each cylinder individually. Connected to the four exhaust ports 33a forming an opening on the front side of the cylinder head 33, bent and extended from the front to the bottom, and further bent to turn to the lower right side of the crank case 30, along the The right side extends rearward and is connected to the collection exhaust pipe 50B. [0022] A catalyst built-in pipe 60 is connected to the downstream end 50b of the collection exhaust pipe 50B in the extending direction, and an exhaust muffler pipe 70 connected to the catalyst built-in pipe 60 is arranged at the lower part of the internal combustion engine 3. The so-called underbody exhaust pipe (muffler) is formed behind the oil receiving pan 35 and in front of the rear wheels 12. The majority of the exhaust muffler pipe 70 is covered by the muffler protector 71 from the right side, and the tail pipe 72 of the exhaust muffler pipe 70 is arranged in the opening 71 a provided in the muffler protector 71. (2) FIG. 2 is a perspective view showing an exhaust device 5 including “four primary exhaust pipes 50A, a collective exhaust pipe 50B, a catalyst internal pipe 60, and an exhaust muffler pipe 70”. The muffler protector 71 is displayed in a state of "removed from the exhaust muffler 70". [0023] The exhaust muffler pipe 70 has a housing 73 composed of a plurality of types of structural surfaces 74, and a structural surface 74 connected to the "catalyst internal pipe 60 connected to the collective exhaust pipe 50B" and facing the front of the vehicle. Is arranged as the connection surface 74A to extend in the vehicle left-right direction yy. The catalyst built-in tube 60 is connected to the connection surface 74A in the vehicle's top view with an inclination angle θ relative to the vehicle front-rear direction xx (refer to Section 4). Figure). In the second figure, 75 is an assembly bracket for assembling the exhaust muffler pipe 70 to the vehicle body frame 2, and 76 is an assembly stay for assembling the muffler protector 71 to the exhaust muffler pipe 70. [0024] FIG. 3 is a left side view of the exhaust device 5 in which the muffler protector 71 and a part of the primary exhaust pipe 50A are omitted, and FIG. 4 is the exhaust gas shown in the direction of arrows IV-IV in FIG. 3. Top view of the device 5. As shown in FIG. 3, an expansion chamber 90 is provided in the internal space of the exhaust muffler pipe 70. As shown in FIG. 4, a tube 60 is provided in the catalyst, and is connected to the connection surface 74A at a position connected to the connection surface 74A. It protrudes toward the upstream side, and part of it reaches (enters) the expansion chamber 90. [0025] Therefore, as shown in FIG. 4, the exhaust pipe 50 in the present embodiment has a downstream end 50b of the collective exhaust pipe 50B with respect to the vehicle front-rear direction xx, as shown in FIG. In the case of having an inclination angle θ and connecting the collecting exhaust pipe 50B to the connection surface 74A of the “exhaust muffler pipe 70 arranged to extend in the vehicle left-right direction yy”, it is connected to the downstream of the “collecting exhaust pipe 50B” The extension tube 50 in the direction of the catalyst is provided with a tube 60 protruding from the connecting surface 74A toward the upstream side, and a part of the tube is arranged to enter the expansion chamber 90, and has an inclined angle with respect to the vehicle front-rear direction xx in a plan view of the vehicle. The θ ground is connected to the connection surface 74A, and it is possible to suppress sharp bending of the collecting exhaust pipe 50B near the upstream of the catalyst-installed pipe 60. In addition, since the inclination angle θ with respect to the collective exhaust pipe 50B is formed perpendicularly, the front face of the housing 73 of the exhaust muffler pipe 70, that is, the connection surface 74A, is inclined with respect to the left and right directions of the vehicle and backed up, so it can be avoided The capacity of the expansion chamber 90 of the exhaust muffler pipe 70 is sacrificed. [0026] In addition, the internal combustion engine 3 of this embodiment is a 4-cylinder internal combustion engine (engine) in which four cylinders are arranged in the vehicle left-right direction yy. As shown in FIG. 4, the exhaust pipe 50 has a single row of each cylinder. The air pipe 50A and the collective exhaust pipe 50B that can be merged with the primary exhaust pipe 50A of each cylinder are connected to the catalyst at the downstream end 50b of the collective exhaust pipe 50B in the same direction as the downstream end 50b. The pipe 60 is provided, and the catalyst inner pipe 60 is extended to have an inclination angle θ with respect to the vehicle front-rear direction xx in a plan view of the vehicle. Therefore, the connection portion between the collecting exhaust pipe 50B and the catalyst inner pipe 60 is not bent, and as a result, the exhaust gas can flow to the entire catalyst 65 provided in the catalyst inner pipe 60 without being biased. , Can make full use of purification performance. [0027] As shown in FIG. 4, the casing 73 of the exhaust muffler 70 is formed by welding the left and right divided bodies 73L and 73R together. A catalyst tube 60 is provided in the connecting surface 74A so that the central axis P thereof coincides with the joint portions 80 of the left and right divided bodies 73L and 73R in the vehicle top view, and is sandwiched by the left and right divided bodies 73L and 73R. And welded together to form an integration with the exhaust muffler. In addition, the joint portions 80 of the left and right divided bodies 73L and 73R are formed along the vehicle front-rear direction xx, and are formed so as to sandwich the end edge 81 of the catalyst inner tube 60: along the surface of the catalyst inner tube 60 In the catalyst, a tube joint portion 81 extending obliquely toward the outside is provided in the direction of the central axis P of the tube 60 in the catalyst. Therefore, with respect to the built-in catalyst tube 60, the welded bonding line of the left split body 73L and the right bonded body 73R is arranged in equal divisions (equivalent) to achieve the left and right of the catalyst built-in tube 60 and the exhaust muffler pipe. The balance of bonding strength between 70.的 The number 77 shown in Figures 4 and 3 is a heat shield. [0028] As in FIG. 4, the cross-sectional shape of the catalyst internal tube 60 is shown in a two-point lock line, and the catalyst internal tube 60 has a circular cross section. In addition, the exhaust muffler pipe 70 is formed on a connection surface 74A extending in the vehicle left-right direction yy and connected to a "catalyst built-in tube 60 having an inclined angle θ with respect to the vehicle front-rear direction xx". As its opening shape 82a is shown as a two-point lock line in FIG. 4, it passes through the circular cross-section body obliquely, so it forms an oval shape. The connection port 82 is welded to the tube 60 of the catalyst, and is connected to the tube 60 inside the catalyst. Peripheral surface. At this time, since the connection port 82 passing through the catalyst inner tube 60 is formed in an oval shape, the welding length between the connection port 82 and the outer peripheral surface of the catalyst inner tube 60 is increased, and the coupling rigidity can be improved. [0029] As shown in FIG. 3, the upper and lower heights of the front portion 70a of the exhaust muffler 70 are small, and the upper and lower heights of the rear portion 70b are large. In the first embodiment, the rear portion has a larger vertical height. 70b, the interior of the expansion chamber 90 is divided into upper and lower parts by the upper and lower partition walls 91 to form a lower expansion chamber 90A and an upper expansion chamber 90B. The upper and lower partition walls 91 are welded and fixed to the inner surface of the outer shell 73 of the exhaust muffler pipe 70 by welding flange portions 91a formed around the upper and lower partition walls 91 above the catalyst inner pipe 60 in a side view of the vehicle. [0030] That is, the exhaust muffler pipe 70 is located above the catalyst built-in pipe 60 in the side view of the vehicle, and has the upper and lower partition walls 91 that divide the expansion chamber 90 into upper and lower parts. In the case where a plurality of expansion chambers 90 are formed, the expansion chamber 90 can be divided into upper and lower portions so as not to interfere with the catalyst built-in tube 60, and a part of the catalyst built-in tube 60 can be accommodated and arranged in one expansion chamber 90. And form another expansion chamber. (1) Specifically, a part of the catalyst built-in tube 60 may be arranged in the lower expansion chamber 90A, and an upper expansion chamber 90B may be formed above the lower expansion chamber 90A. [0031] In addition, a catalyst internal pipe 60 is disposed in a portion of the lower expansion chamber 90A, and a discharge duct 61 is connected to a downstream side thereof. The discharge duct 61 extends along the upper and lower partition walls 91 in a vehicle side view. In this way, since the exhaust duct 61 extends along the upper and lower partition walls 91 below the upper and lower partition walls 91, it is possible to prevent interference between the exhaust duct 61 and the upper and lower partition walls 91, and to increase exhaust gas. The length of the duct 61. [0032] In addition, the upper and lower partition walls 91 are formed by bending at the end portion 91b of the catalyst-integrated tube 60 side toward the catalyst-integrated tube 60. Therefore, the catalyst-integrated tube 60 and the top-and-bottom partition wall 91 are formed. Increasing the interval can suppress the thermal influence of the tube 60 inside the catalyst on the upper and lower partition walls 91, and suppress the thermal expansion and deformation of the upper and lower partition walls 91. [0033] In addition, as shown in FIG. 3 and referring to FIG. 4, the communication tube 92 is provided to penetrate the upper and lower partition walls 91, and the inlet opening 92a of the communication tube 92 forms an opening toward the lower expansion chamber 90A. The outlet opening 61b of the discharge duct 61 of the lower expansion chamber 90A and the inlet opening 92a of the communication pipe 92 are arranged to maintain a certain space, so that the distance of the gas flow is increased, and the noise reduction effect is increased. In addition, the downstream side of the communication pipe 92 is bent rearward in the upper expansion chamber 90B, and the downstream end 92b is supported by a support pillar 93 erected on the upper and lower partition walls 91, and the communication pipe 92 in front of the downstream end 92b, A porous portion 92c is provided. [0034] In the upper expansion chamber 90B, an upstream side of the tail pipe 72 is provided to penetrate the housing 73 of the exhaust muffler pipe 70, and an inlet opening 72a thereof forms an opening. In addition, the downstream end 72b of the tail pipe 72 is opened to the outside gas (that is, the outside) and emits exhaust gas. In other words, the exhaust gas passes through the exhaust pipe 50 (50A, 50B) through the catalyst built-in pipe 60, is purified by the catalyst 65 in the catalyst built-in pipe 60, and then enters the lower part through the outlet opening 61b of the exhaust duct 61. The expansion chamber 90A passes through the communication pipe 92 from the lower expansion chamber 90A, passes through the porous portion 92c, and enters the upper expansion chamber 90B. After being silenced, it is discharged to the outside through the tail pipe 72. The lower diaphragm 90A may be referred to as a first inflation chamber, and the upper diaphragm 90B may be referred to as a second inflation chamber. [0035] FIG. 5 is a bottom view of the exhaust device 5 based on the direction of the arrow V-V in FIG. 3 and omitting the muffler protector 71 and a part of the primary exhaust pipe 50A. In FIG. 5, only the inside of the lower expansion chamber 90A is shown in the exhaust muffler pipe 70. The discharge duct 61 on the downstream side of the catalyst built-in pipe 60 is bent to the right, and the outlet opening 61b of the discharge duct 61 is formed to the right. The opening increases the distance of the gas flow from the "inlet opening 92a of the communication pipe 92 opening toward the lower expansion chamber 90A", thereby increasing the noise reduction effect.的 Figure No. 78 shown in Figures 5 and 3 is a protective reinforcing plate. [0036] FIG. 6 is a cross-sectional view of the collective exhaust pipe 50B, the catalyst built-in pipe 60, and the exhaust duct 61 shown in the VI-VI arrow direction in FIG. 5. A catalyst 65 is filled in the catalyst inner tube 60, and the catalyst 65 is an exhaust gas purification catalyst, such as a three-way catalyst carried by a honeycomb-shaped metal carrier. The internal tube 60 of the catalyst according to this embodiment forms a multiple tube structure as shown in FIG. 6. In FIGS. 3 to 5, and FIG. 7 to FIG. 9 of the second embodiment, the catalyst The tube 60 is provided in the medium, and the illustration of the outermost tube 60b in FIG. 6 is omitted. [0037] An exhaust device of a straddle-type vehicle according to a second embodiment of the present invention will be described with reference to FIGS. 1 and 7 to 10. In the second embodiment, the structure of the locomotive 1 as a straddle type vehicle, and the structural relationship between the exhaust pipe 50 (the primary exhaust pipe 50A and the collective exhaust pipe 50B) and the catalyst-built pipe 60 and the exhaust muffler pipe 70 The arrangement relationship is the same as that of the first embodiment except that the structure inside the exhaust muffler is different. In addition, the structure of the catalyst-installed tube 60 is also the same as that of the first embodiment. Therefore, the same parts as those in the first embodiment are denoted by the same drawing numbers, and the description of the same effects produced by the same structure is omitted and simplified. In the following, the differences will be mainly described. [0038] FIG. 7 is a left side view of the exhaust device 5 of the second embodiment in which the muffler protector 71 and the primary exhaust pipe 50A are partially omitted, and FIG. 8 is a view in the direction of arrows VII-VII in FIG. 7. A plan view of the exhaust device 5 is shown. As shown in FIG. 7, an expansion chamber 90 is provided in the internal space of the exhaust muffler pipe 70. As shown in FIG. 8, the catalyst-installed pipe 60 is connected at the same inclination angle θ as in the first embodiment. The position where the surface 74A is connected is arranged so as to protrude from the connection surface 74A toward the upstream side, and a part thereof reaches (enters) the expansion chamber 90. [0039] In addition, the front portion 70a of the exhaust muffler pipe 70 has a smaller vertical height and the rear portion 70b has a larger vertical height. In the second embodiment, the rear portion 70b has a large vertical height in front of the rear portion 70b. The expansion chamber 90 is divided into front and rear partition walls 95. The front and rear partition walls 95 are welded and fixed to the inner surface of the casing 73 of the exhaust muffler tube 70 by welding flange portions 95 a formed around the front and rear partition walls 95. [0040] In the exhaust muffler pipe 70, the inside of the expansion chamber 90 is divided into front and rear by a front-rear partition wall 95 extending in the front-rear direction, and a front expansion chamber 90C is formed in front of the front-rear partition wall 95. At the rear of the front and rear partition walls 95, the upper and lower partition walls 96 are further divided into upper and lower parts to form a rear upper expansion chamber 90D and a rear lower expansion chamber 90E. The upper and lower partition walls 96 are welded and fixed to the inner surface of the casing 73 of the exhaust muffler pipe 70 by welding the flange 96a formed around the upper and lower partition walls 96 above the catalyst inner pipe 60 in the side view of the vehicle. In the second embodiment, although the catalyst-installed tube 60 is connected to the front expansion chamber 90C in the same configuration as in the first embodiment, the exhaust duct 61 as in the first embodiment is not provided. [0041] In this way, since the exhaust muffler pipe 70 is higher than the catalyst built-in pipe 60 in the side view of the vehicle, and has the upper and lower partition walls 96 that divide the expansion chamber 90 into upper and lower parts, the exhaust muffler pipe 70 When multiple expansion chambers 90 are formed inside, the expansion chamber 90 can be divided into upper and lower parts so as not to interfere with the catalyst built-in tube 60, and a part of the catalyst built-in tube 60 can be accommodated and arranged in one expansion chamber 90. Inside and form another expansion chamber. [0042] As shown in FIG. 7, in the second embodiment, the exhaust muffler 70 has a front and rear partition wall 95 that divides the expansion chamber 90 into front and rear sides, and the front and rear partition walls 95 are inclined so that the lower portion 95b is more than the upper portion 95c. Keep the tube 60 away from the catalyst. The exhaust muffler has an upper and lower partition wall 96 that divides the expansion chamber 90 into upper and lower portions in the vehicle side view above the catalyst inner tube 60. Therefore, the upper portion 95c of the front and rear partition walls 95 is closer to the lower portion 95b. The inner tube 60 is provided in the catalyst, and the lower portion 95b is inclined toward the "side away from the inner catalyst tube 60" than the upper portion 95c. Therefore, the distance from the inner tube 60 to the front and rear partition walls 95 can be more ensured and reduced. The outflow resistance of the exhaust gas from the catalyst built-in pipe 60 improves the exhaust gas exhaust efficiency. [0043] In the exhaust muffler pipe 70 of the second embodiment, as shown in FIG. 7 and also with reference to FIG. 8, the catalyst built-in pipe 60 is connected to the connection surface 74A of the exhaust muffler pipe 70 and faces An opening is formed in the front expansion chamber 90C, and a first communication pipe 97 penetrating the front and rear partition walls 95 from the front expansion chamber 90C side to the rear upper expansion chamber 90D side and the rear lower expansion chamber 90E are provided from the rear upper expansion chamber 90D side. The second communication pipe 98 which passes through the upper and lower partition walls 96 on its side. In the rear lower expansion chamber 90E, the upstream side of the tail pipe 72 is provided to penetrate the casing 73 of the exhaust muffler tube 70 and the upper and lower partition walls 96, and passes through the rear upper expansion chamber 90D, and the inlet opening 72a thereof forms an opening. In addition, the downstream end 72b of the tail pipe 72 is opened to the outside gas (that is, the outside) and emits exhaust gas. [0044] That is, the exhaust gas passes from the exhaust pipe 50 (50A, 50B) through the catalyst built-in pipe 60, is purified by the catalyst 65 in the catalyst built-in pipe 60, and enters the front expansion chamber 90C. The internal expansion chamber 90C enters the upper rear expansion chamber 90D through the first communication pipe 97, and further enters the upper rear expansion chamber 90D through the second communication pipe 98. After being silenced, it is discharged to the outside through the tail pipe 72. The front expansion chamber 90C may be referred to as a first expansion chamber, the rear upper expansion chamber 90D may be referred to as a second expansion chamber, and the lower rear expansion chamber 90E may be referred to as a third expansion chamber. [0045] FIG. 9 is a bottom view of the exhaust device 5 based on the direction of arrows IX-IX in FIG. 7 and omitting the muffler protector 71 and the primary exhaust pipe 50A. In FIG. 9, only the inside of the front expansion chamber 90C and the inside of the rear lower expansion chamber 90E are shown in the exhaust muffler pipe 70, and the discharge of Embodiment 1 is not provided on the downstream side of the catalyst built-in pipe 60. The catheter 61 is opened toward the inside of the front expansion chamber 90C.图 Figures 79 and 7 shown in Figure 9 and Figure 7 are soundproof material storage sections. [0046] FIG. 10 is a rear cross-sectional view of the rear portion 70B of the exhaust muffler tube 70 shown in the direction of arrows X-X in FIG. 7. The rear portion 70b is divided into a rear upper expansion chamber 90D and a rear lower expansion chamber 90E, and an outlet opening 97b of the first communication pipe 97 of the rear upper expansion chamber 90D by dividing the expansion chamber 90 into upper and lower upper and lower partition walls 96. The inlet opening 98a connected to the second communication pipe 98 is arranged to maintain a certain space, so that the distance of the gas flow is increased, and the noise reduction effect is further increased. The outlet opening 98b of the second communication pipe 98 is bent to the right in the lower rear expansion chamber 90E. As shown in FIG. 8, the outlet opening 98b of the second communication pipe 98 in the rear lower expansion chamber 90E and the tail pipe 72 The inlet openings 72a are also arranged to increase the gas flow distance. [0047] Although the first embodiment and the second embodiment of the present invention have been described above, the aspects of the present invention are not limited to the above-mentioned embodiments. Of course, the invention can be modified in various ways without departing from the scope of the present invention. State implementation constructs. For example, internal combustion engines (engines) are not limited to in-line 4-cylinders, and straddle-type vehicles are not limited to locomotives, but also include buggy cars.为了 Although the internal combustion engine arranged on the left and right in the drawing is described in the embodiment for the convenience of explanation, even the arrangement other than the left and right arrangement is included in the present invention.

[0048]

1‧‧‧ locomotive

3‧‧‧ Engine

4‧‧‧power unit

5‧‧‧Exhaust

30‧‧‧Crank case

33‧‧‧Cylinder head

33a‧‧‧Exhaust port

35‧‧‧oil pan

50‧‧‧ exhaust pipe

50a‧‧‧upstream

50b‧‧‧ downstream

50A‧‧‧Primary exhaust pipe ("exhaust pipe" in the present invention)

50B‧‧‧collection exhaust pipe (the "merging part" of the "exhaust pipe" in the present invention)

60‧‧‧Built in catalyst

60a‧‧‧cross section shape

61‧‧‧Exhaust catheter

61b‧‧‧Exit opening

65‧‧‧ catalyst

70‧‧‧Exhaust Silencer

70a‧‧‧front

70b‧‧‧ rear

72‧‧‧ tailpipe

72a‧‧‧ entrance opening

72b‧‧‧ downstream

73‧‧‧shell

73L‧‧‧left split

73R‧‧‧Right split

74‧‧‧ constituting surface

74A‧‧‧Connecting surface

80‧‧‧ junction

81‧‧‧End edge, pipe joint

82‧‧‧Connector

82a‧‧‧ opening shape

90‧‧‧ Expansion chamber

90A‧‧‧lower expansion chamber

90B‧‧‧Upper expansion chamber

90C‧‧‧Front expansion chamber

90D‧‧‧ Rear upper expansion chamber

90E‧‧‧Rear lower expansion chamber

91‧‧‧ next door

91b‧‧‧ tip

92‧‧‧ connecting pipe

95‧‧‧ next door

95a‧‧‧lower

95b‧‧‧upper

96‧‧‧ next door

97‧‧‧The first communication pipe

98‧‧‧ 2nd connecting pipe

x-x‧‧‧ vehicle front and rear direction

y-y‧‧‧ Vehicle left and right

P‧‧‧ (center tube 60 in the catalyst)

θ‧‧‧ tilt angle

[0014] FIG. 1: A right side view of a locomotive according to an embodiment of the present invention. FIG. 2 is a perspective view showing an exhaust device of Embodiment 1 including “four primary exhaust pipes, a collective exhaust pipe, a catalyst-integrated pipe, and an exhaust muffler pipe”. FIG. 3: A left side view of the exhaust device of the first embodiment in which a muffler protector and a part of the primary exhaust pipe are omitted. Figure 4: A plan view of the exhaust device shown in the direction of arrows IV-IV in Figure 3. Figure 5: The bottom view of the exhaust device of the muffler protector and the primary exhaust pipe is shown in the direction of the arrow V-V in Figure 3. Figure 6: Sectional view of the collective exhaust pipe, catalyst internal pipe, and discharge duct shown in the VI-VI arrow direction in Figure 5. FIG. 7 is a left side view of the exhaust device of Embodiment 2 in which the muffler protector and the primary exhaust pipe are partially omitted. Figure 8: A plan view of the exhaust device shown in the direction of arrows VIII-VIII in Figure 7. Figure 9: The bottom view of the exhaust device of the muffler protector and the primary exhaust pipe is omitted as shown in the direction of arrows IX-IX in Figure 7. Figure 10: A rear cross-sectional view of the rear part of the exhaust muffler shown in the direction of the arrow X-X in Figure 7.

Claims (8)

An exhaust device for a straddle type vehicle is a power unit (4) including an internal combustion engine (3) is mounted on a straddle type vehicle (1), and has an exhaust pipe (50), and an upstream end is connected to the internal combustion engine ( 3) constituting an exhaust gas passage for discharging exhaust gas; and an exhaust muffler pipe (70) connected to a downstream end (50b) of the exhaust pipe (50) in a catalyst provided in an extension direction thereof An exhaust device for a straddle-type vehicle having a pipe (60) and an expansion chamber (90) provided in an internal space of the exhaust muffler (70), wherein the exhaust muffler (70) is provided with The casing (73) composed of a plurality of types of structural surfaces (74) is connected to the aforementioned structural surface (74) of the catalyst inner tube (60) and faces the front of the vehicle, and is arranged as a connecting surface (74A) to face The vehicle's left-right direction (yy) extends, and the catalyst built-in tube (60) connected to the exhaust pipe (50) has an inclination angle (θ) with respect to the vehicle front-rear direction (xx) in a plan view of the vehicle. ) Ground is connected to the connection surface (74A), and a position where the tube (60) and the connection surface (74A) are connected in the catalyst is disposed, and a part of the tube (60) is disposed in the catalyst, and is arranged Into the expansion chamber (90); the casing (73) of the exhaust muffler (70) is composed of a plurality of divided bodies (73L, 73R) divided in the left-right direction of the vehicle, and the plurality of divided bodies The coupling portion (80) in the front-rear direction of the vehicle between (73L, 73R) extends so as to form an inclination angle with respect to the central axis (P) of the catalyst built-in tube (60). The exhaust device for a straddle-type vehicle according to claim 1, wherein the internal combustion engine (3) is a multi-cylinder internal combustion engine in which a plurality of cylinders are arranged in the left-right direction (yy) of the vehicle, and the exhaust pipe (50) has The merging section (50B) where the exhaust pipes (50A) of the plurality of cylinders can be merged. The downstream end (50b) of the merging section (50B) is connected with the catalyst internal pipe (60), and the vehicle is viewed from a plan view In the above, the catalyst built-in tube (60) has an inclination angle (θ) with respect to the vehicle front-rear direction (xx) and extends toward the same direction as the downstream end (50b). The exhaust device for a straddle-type vehicle as described in claim 1 or claim 2, wherein the outer shell (73) of the exhaust muffler pipe (70) is made by welding the left and right divided bodies (73L, 73R) together. In the structure, a tube (60) is provided in the catalyst, and a central axis (P) of the connecting surface (74A) is aligned with a joint portion (80) of the left and right divided bodies (73L, 73R) in a vehicle top view. It is integrated with the exhaust muffler pipe (70) by being sandwiched and welded by the left and right divided bodies (73L, 73R), and the joint portion (80 of the left and right divided bodies (73L, 73R)) ) Is formed along the front-rear direction (xx) of the vehicle, and is formed by sandwiching the end edge (81) of the catalyst inner tube (60): along the surface of the catalyst inner tube (60), facing The catalyst is provided with a tube joint portion (81) extending obliquely outward in the center axis (P) direction of the tube (60). The exhaust device for a straddle-type vehicle as described in claim 1 or claim 2, wherein the catalyst built-in pipe (60) has a circular cross section and is formed on the connection surface (70) of the exhaust muffler pipe (70) ( 74A), and the connection port (82) connected to the catalyst inner tube (60) is formed in an oval shape, and is welded to the outer peripheral surface of the catalyst inner tube (60). The exhaust device for a straddle-type vehicle as described in claim 1 or claim 2, wherein the exhaust muffler pipe (70) is located above the catalyst inner pipe (60) in a side view of the vehicle, The expansion chamber (90) is divided into upper and lower partition walls (91, 96). The exhaust device for a straddle-type vehicle according to claim 5, wherein the upper and lower partition walls (91) are provided with an end on the catalyst (60) side in the catalyst, and a pipe (60) is provided toward the catalyst. The upper part is bent. The exhaust device for a straddle-type vehicle according to claim 5, wherein a tube (60) is provided in the catalyst, a discharge duct (61) is connected to a downstream side thereof, and the discharge duct is viewed from the side of the vehicle (61) It extends along the said upper and lower partition wall (91). The exhaust device for a straddle-type vehicle according to claim 5, wherein the exhaust muffler pipe (70) has a front and rear partition wall (95) that divides the expansion chamber (90) into front and rear partitions (95) 95) Tilt so that the lower part (95b) is farther away than the upper part (95c) from the catalyst inner tube (60).