Exhaust system

Abstract

To suppress a reduction in the output of an engine with the improvement of the warming-up performance of a catalyst by an exhaust resonator.SOLUTION: An exhaust system (40) purifies exhaust gas exhausted from exhaust ports (31L, 31R) of an engine (20). In the exhaust system, there are provided exhaust pipes (41L, 41R) into which the exhaust gas flows from the exhaust ports of the engine, a catalyst (45) arranged in front of the engine in the downstream parts of the exhaust pipes, and an exhaust resonator (42) connected to the exhaust pipes in the upstream part of the catalyst.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an exhaust system. [Background technology]

[0002] Conventionally, there has been known an exhaust system for a saddle-type vehicle in which an exhaust resonator is provided below the engine (see, for example, Patent Document 1). The exhaust resonator in Patent Document 1 is a Helmholm-type resonator, and is connected to a connecting pipe that branches off from the middle of the exhaust pipe. A silencer is connected downstream of the exhaust pipe, and the exhaust resonator is supported from below on the outer surface of the silencer. The exhaust resonator forms an expansion chamber in part of the exhaust pipe upstream of the silencer, thereby adjusting exhaust pulsation and obtaining the desired engine output without changing the length of the exhaust pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5899017 Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, by bringing the catalyst closer to the exhaust port, the warm-up performance of the catalyst can be improved by the high-temperature exhaust gas, but the engine output may decrease due to a mismatch between the exhaust pulsation and the exhaust timing. In this case, since the exhaust pipe length is shortened by bringing the catalyst closer to the exhaust port, it is difficult to adjust the exhaust pulsation by adjusting the exhaust pipe length. Countermeasures such as increasing the engine displacement or changing the intake system can be considered, but both of these will increase costs and require changes to the layout. In addition, the positional relationship between the exhaust resonator described in Patent Document 1 and the catalyst has not been considered.

[0005] The present invention has been made in consideration of the above-mentioned points, and has an object to provide an exhaust device that can suppress the decrease in engine output that accompanies the improvement of the warm-up performance of the catalyst by using an exhaust resonator. [Means for solving the problem]

[0006] An exhaust system according to one aspect of the present invention is an exhaust system that purifies exhaust gas discharged from an exhaust port of an engine, and includes an exhaust pipe into which exhaust gas flows from the exhaust port of the engine, a catalyst disposed in front of the engine downstream of the exhaust pipe, and an exhaust resonator connected to the exhaust pipe upstream of the catalyst. The catalyst is disposed on one side in the vehicle width direction from a center line extending in the vertical direction of the vehicle, and the exhaust resonator is connected to the exhaust pipe on the one side, and the exhaust pipe is an exhaust pipe on one side and the other side in the vehicle width direction across the center line, and the exhaust pipe on the other side extends in the vehicle width direction to one side, and the exhaust resonator extends from the exhaust pipe on the one side to the other side along the exhaust pipe on the other side. This solves the above problem. Effect of the Invention

[0007] According to the exhaust system of one aspect of the present invention, even if the exhaust pipe is shortened by moving the catalyst closer to the exhaust port to improve the catalyst warm-up performance, the exhaust pulsation can be adjusted by the exhaust resonator connected to the exhaust pipe. Therefore, it is possible to suppress the decrease in engine output due to the improvement of the catalyst warm-up performance without changing the exhaust pipe length. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of the engine according to the embodiment. [Diagram 2] FIG. 2 is a side view of the engine of the present embodiment. [Diagram 3] FIG. 2 is a front view of the engine of the present embodiment. [Figure 4] FIG. 2 is a rear view of the exhaust device of the present embodiment. [Diagram 5] FIG. 2 is a top view of the engine of the present embodiment. [Figure 6] FIG. 2 is a diagram showing an exhaust resonator according to a first modified example. [Figure 7] FIG. 11 is a diagram showing an exhaust resonator according to a second modified example. [Figure 8] FIG. 13 is a diagram showing an exhaust resonator according to a third modified example. [Figure 9]FIG. 13 is a diagram showing an exhaust resonator according to a fourth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An exhaust device according to one aspect of the present invention purifies exhaust gas discharged from an exhaust port of an engine. In the exhaust device, exhaust gas flows into an exhaust pipe from the exhaust port of the engine, a catalyst is disposed in front of the engine downstream of the exhaust pipe, and an exhaust resonator is connected to the exhaust pipe upstream of the catalyst. Even if the exhaust pipe is shortened by bringing the catalyst closer to the exhaust port to improve the warm-up performance of the catalyst, exhaust pulsation can be adjusted by the exhaust resonator connected to the exhaust pipe. Therefore, a decrease in engine output due to the improvement of the warm-up performance of the catalyst can be suppressed without changing the length of the exhaust pipe. EXAMPLES

[0010] Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. Fig. 1 is a perspective view of the engine of the present embodiment. Fig. 2 is a side view of the engine of the present embodiment. In the following drawings, the arrow FR indicates the front of the vehicle, the arrow RE indicates the rear of the vehicle, the arrow L indicates the left side of the vehicle, and the arrow R indicates the right side of the vehicle.

[0011] 1 and 2, a saddle-type vehicle is configured by mounting various parts such as an engine 20 and an electrical system on a double-cradle-type body frame 10. The body frame 10 has a pair of main frames 12L, 12R branching off to the left and right from a head pipe 11 and extending rearward, a down frame 13 extending downward from the head pipe 11, and a pair of lower frames 14L, 14R branching off to the left and right from a lower end of the down frame 13 and extending diagonally downward. The rear sides of the main frames 12L, 12R are bent downward, and the lower sides of the lower frames 14L, 14R are bent rearward and joined to the main frames 12L, 12R.

[0012] The engine 20 is a parallel two-cylinder engine with a cylinder 22 disposed above a crankcase 21. A cylinder head 23 is attached to the top of the cylinder 22, and a head cover 24 is attached to the top of the cylinder head 23. An oil pan 25 in which oil is stored is attached to the bottom of the crankcase 21. A magneto cover 26 that covers the magneto chamber inside the case is attached to the left side of the crankcase 21, and a clutch cover 27 that covers the clutch chamber inside the case is attached to the right side of the crankcase 21. An oil filter 28 that removes foreign matter from the oil is attached to the front of the crankcase 21.

[0013] A radiator 32 that dissipates heat from the cooling water in the engine 20 is attached to the front side of the down frame 13. An exhaust device 40 that purifies exhaust gas discharged from a pair of exhaust ports 31L, 31R (see FIG. 3) of the engine 20 is attached below the radiator 32. The exhaust device 40 is provided with a primary catalyst (catalyst) 45 and a secondary catalyst 53. The primary catalyst 45 is disposed in front of the engine 20, and the secondary catalyst 53 is disposed below the engine 20. The primary catalyst 45 is brought close to the exhaust ports 31L, 31R and activated early, and the secondary catalyst 53 is activated early by the exhaust gas heated by the catalytic reaction.

[0014] However, as a result of the primary catalyst 45 being brought closer to the exhaust ports 31L, 31R, the engine output may decrease due to a mismatch between the exhaust pulsation and the exhaust timing. In this case, since the exhaust pipes 41L, 41R between the exhaust ports 31L, 31R and the primary catalyst 45 are short, it is difficult to adjust the exhaust pulsation by adjusting the exhaust pipe length. It is possible to compensate for the decrease in engine output by changing the design of the engine 20 or the intake system, but this has the disadvantage of increasing costs and requiring changes to the layout. Therefore, in the exhaust device 40 of this embodiment, an exhaust resonator 42 is connected to the exhaust pipe 41L upstream of the primary catalyst 45 to adjust the exhaust pulsation.

[0015] The exhaust system will be described in detail below with reference to Figures 3 and 4. Figure 3 is a front view of the engine of this embodiment. Figure 4 is a rear view of the exhaust system of this embodiment.

[0016] As shown in Figures 3 and 4, the exhaust system 40 includes exhaust pipes 41L and 41R, an exhaust resonator 42, a collecting pipe 43, a primary catalyst 45, a bent pipe 47, a chamber 51, a secondary catalyst 53, and a tail pipe 54. The exhaust system 40 forms an exhaust passage that wraps around from the front of the engine 20 downward and extends rearward. In the exhaust system 40, exhaust gas flows from the exhaust ports 31L and 31R of the engine 20 into the exhaust pipes 41L and 41R, and air pollutants such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen compounds (NOx) in the exhaust gas are purified by the primary catalyst 45 and the secondary catalyst 53. In the exhaust system 40, the exhaust noise is suppressed by the chamber 51.

[0017] The exhaust pipes 41L and 41R extend from one side (left side) and the other side (right side) in the vehicle width direction across a center line C extending in the vertical direction of the vehicle. The exhaust pipe 41L on one side extends forward from the exhaust port 31L and is connected to a collecting pipe 43, and the exhaust pipe 41R on the other side extends forward from the exhaust port 31R and then extends leftward and is connected to the collecting pipe 43. In this way, the exhaust pipe 41L is formed shorter than the exhaust pipe 41R, and a difference is provided between the exhaust pipe lengths of the exhaust pipes 41L and 41R. An exhaust resonator 42 is connected to the middle of the exhaust pipe 41L, and the exhaust pulsation is adjusted by the exhaust resonator 42. The details of the exhaust resonator 42 will be described later.

[0018] The upstream side of the collecting pipe 43 is bifurcated, and the downstream side of the collecting pipe 43 is formed in a cylindrical shape. The exhaust pipes 41L, 41R are connected to the upstream side of the collecting pipe 43, and a primary catalyst case 44 that houses a primary catalyst 45 is formed on the downstream side of the collecting pipe 43. Exhaust gas that passes through the exhaust pipes 41L, 41R is collected in the collecting pipe 43 and sent to the primary catalyst 45. A mounting boss 46 for an upstream exhaust gas sensor (not shown) is formed on the outer circumferential surface of the collecting pipe 43. The upstream exhaust gas sensor detects the average oxygen concentration of the exhaust gas flowing in from the exhaust pipes 41L, 41R. The detection result of the upstream exhaust gas sensor is used for feedback control of the fuel injection amount.

[0019] The primary catalyst 45 is a small catalyst that functions as a starter catalyst, and is disposed downstream of the exhaust pipes 41L and 41R and in front of the engine 20. As described above, since the exhaust pipe 41L is shorter than the exhaust pipe 41R, the collecting pipe 43 is located to the left of the center line C extending in the vertical direction of the vehicle (one side in the vehicle width direction), and the primary catalyst 45 is housed in the primary catalyst case 44 of the collecting pipe 43. The primary catalyst 45 is positioned at a height where it overlaps with the lower frame 14L in a front view. The primary catalyst 45 is formed by attaching a catalytic substance to the surface of a honeycomb- or lattice-shaped partition plate, and when the exhaust gas flowing in from the collecting pipe 43 passes through the primary catalyst 45, air pollutants react with oxygen and are purified.

[0020] Since the length of the exhaust pipe 41L is short, high-temperature exhaust gas flows from the exhaust port 31L into the primary catalyst 45, which warms up the primary catalyst 45 in a short time and improves the purification performance of the exhaust gas from the exhaust port 31L. In this case, the length of the exhaust pipe 41R is long and the temperature of the exhaust gas is likely to drop, but the high-temperature exhaust gas from the exhaust pipe 41L warms up the primary catalyst 45 in a short time, which improves the purification performance of the exhaust gas from the exhaust port 31R. In this way, by intentionally setting a difference in pipe length between the exhaust pipes 41L and 41R, early activation of the primary catalyst 45 is achieved.

[0021] The bent pipe 47 is formed into a generally L-shaped pipe with a vertical cylinder section on the upstream side and a horizontal cylinder section on the downstream side connected together. The collector pipe 43 is connected to the upstream side of the bent pipe 47, and a chamber 51 is connected to the downstream side of the bent pipe 47. Exhaust gas that has passed through the primary catalyst 45 in the collector pipe 43 is led to the chamber 51 below the engine 20 by the bent pipe 47. A mounting boss 48 for a downstream exhaust gas sensor (not shown) is formed on the outer circumferential surface of the bent pipe 47. The average oxygen concentration of the exhaust gas that has passed through the primary catalyst 45 is detected by the downstream exhaust gas sensor. The detection result of the downstream exhaust gas sensor is used for feedback control of the fuel injection amount and for diagnosing catalyst deterioration.

[0022] A secondary catalyst case 52 that houses a secondary catalyst 53 is formed on the upstream side of the chamber 51. The secondary catalyst case 52 extends diagonally rearward from the left side to the right side (from one side to the other side in the vehicle width direction). The secondary catalyst 53 is a large catalyst that functions as a main catalyst, and is disposed below the engine 20 downstream of the bent pipe 47. The secondary catalyst 53 is located to the right of the center line C (the other side in the vehicle width direction). The secondary catalyst 53 is formed by attaching a catalytic substance to the surface of a honeycomb- or lattice-shaped partition plate, and when the exhaust gas flowing in from the bent pipe 47 passes through the secondary catalyst 53, air pollutants react with oxygen and are purified.

[0023] A muffler chamber (not shown) for reducing exhaust noise is formed downstream of the chamber 51. The chamber 51 extends in the front-rear direction to the right of the center line C. When exhaust gas enters the muffler chamber from the secondary catalyst 53, the exhaust gas expands in the muffler chamber, thereby reducing the exhaust noise. The outer wall of the chamber 51 has a double-cylinder structure, and sound-absorbing glass wool is packed in the gap between the inner and outer cylinders. A tail pipe 54 extends rearward from the downstream side of the chamber 51, and a muffler (not shown) is connected downstream of the tail pipe 54. In this way, the exhaust noise of the exhaust device 40 is reduced in two stages by the chamber 51 and the muffler.

[0024] The exhaust resonator will be described with reference to Figures 3 and 5. Figure 5 is a top view of the engine of this embodiment. For ease of explanation, the vehicle body frame is omitted in Figure 5.

[0025] As shown in Fig. 3, a cylindrical exhaust resonator 42 with a bottom is connected to the middle of the exhaust pipe 41L upstream of the primary catalyst 45, and the exhaust resonator 42 extends from the exhaust pipe 41L along the exhaust pipe 41R, over the down frame 13, to the right exhaust port 31R. The exhaust resonator 42 is positioned above the collecting pipe 43 and forward and above the crankshaft 33 (see Fig. 2). The outer diameter of the exhaust resonator 42 is formed to be approximately the same as the outer diameter of the exhaust pipe 41L, and the passages in the exhaust resonator 42 and the passages in the exhaust pipe 41L are connected through a communication hole. The diameter of the communication hole is adjusted to a size that obtains an optimal exhaust pulsation effect, with the inner diameter of the exhaust resonator 42 as the maximum diameter.

[0026] Exhaust resonator 42 is disposed between exhaust pipes 41L, 41R, and the existing free space in front of engine 20 is effectively utilized to adjust the volume of exhaust resonator 42. Because exhaust resonator 42 is disposed in the free space, the impact of exhaust resonator 42 on the layout of other components is minimized. Also, because exhaust resonator 42 is formed as a long straight pipe in the vehicle width direction, the volume can be easily adjusted by the length of exhaust resonator 42. The length (volume) of exhaust resonator 42 is adjusted to a size that fits between exhaust pipes 41L, 41R and provides an optimal exhaust pulsation effect.

[0027] As shown in FIG. 5, the exhaust resonator 42 extends along the left and right extensions of the exhaust pipe 41R, making the exhaust resonator 42 less noticeable and improving the appearance. Furthermore, the exhaust resonator 42 is positioned above and behind the left and right extensions of the exhaust pipe 41R. By positioning the exhaust resonator 42 above the left and right extensions of the exhaust pipe 41R, the primary catalyst 45 can be brought closer to the exhaust port 31L, and the primary catalyst 45 does not interfere with the front wheel (not shown). By positioning the exhaust resonator 42 behind the exhaust pipe 41R, the exhaust resonator 42 is hidden behind the exhaust pipe 41R, improving the appearance. Furthermore, contact between the rider and the exhaust resonator 42 is avoided, ensuring safety.

[0028] In a side view of the vehicle, exhaust resonator 42 overlaps exhaust pipes 41L, 41R (see FIG. 2), and is positioned so as not to protrude forward of exhaust pipes 41L, 41R. Radiator 32 is positioned above exhaust resonator 42 (see FIG. 2), and exhaust resonator 42 is positioned rearward of the front of radiator 32. In this way, exhaust resonator 42 is disposed in a space surrounded by radiator 32, exhaust pipes 41L, 41R, and down frame 13, and these members protect exhaust resonator 42 from external impacts and the like.

[0029] Exhaust resonator 42 branches the exhaust passage of exhaust pipe 41L, creating a flow of exhaust gas that heads toward exhaust resonator 42. Even if exhaust pipe 41L is shortened to improve warm-up performance as described above, exhaust resonator 42 appropriately adjusts exhaust pulsation to match the exhaust timing. Because exhaust resonator 42 is connected to short exhaust pipe 41L, even if a large deviation in exhaust pulsation occurs due to differences in the exhaust pipe lengths of exhaust pipes 41L, 41R, this deviation in exhaust pulsation is corrected by exhaust resonator 42. Therefore, exhaust resonator 42 suppresses a decrease in engine output.

[0030] More specifically, the pressure wave in the exhaust pipe 41L enters the exhaust resonator 42, is reflected at the closed end of the exhaust resonator 42, and is propagated toward the collecting pipe 43. The pressure wave is inverted and reflected at the downstream open end of the exhaust pipe 41L, and is propagated to the upstream side of the exhaust pipe 41L. The part with low pressure density at this time is adjusted to the opening and closing timing of the exhaust valve by the volume of the exhaust resonator 42, etc., to adjust the exhaust pulsation. By connecting the exhaust resonator 42 to the exhaust pipe 41L upstream of the primary catalyst 45 in front of the engine 20, the warm-up performance of the primary catalyst 45 in front of the engine 20 is improved and a sufficient exhaust pulsation effect is obtained.

[0031] As described above, according to this embodiment, even if the exhaust pipe 41L is shortened by bringing the primary catalyst 45 closer to the exhaust port 31L to improve the warm-up performance of the catalyst, the exhaust pulsation is adjusted by the exhaust resonator 42 connected to the exhaust pipe 41L. Therefore, the decrease in engine output due to the improvement of the warm-up performance of the primary catalyst 45 is suppressed without changing the length of the exhaust pipe 41L.

[0032] In this embodiment, the exhaust resonator is supported by a cantilever on the left exhaust pipe, but the exhaust resonator may be fixed to the down frame or the right exhaust pipe via a bracket or the like. Also, as shown in the first modified example in Fig. 6, the exhaust resonator 62 may extend from the exhaust pipe 61L along the exhaust pipe 61R, and the exhaust resonator 62 may be welded to the outer peripheral surfaces of the left and right extending portions of the exhaust pipe 61R. This allows the exhaust resonator 62 to be stably supported.

[0033] In addition, in this embodiment, the exhaust resonator is directly connected to the left exhaust pipe, but the exhaust resonator may be connected to the left exhaust pipe via a connecting pipe. For example, as shown in the second modified example of Fig. 7, a thin-diameter connecting pipe 66 may extend from the left exhaust pipe 65L toward the right side, and a thick-diameter exhaust resonator 67 may be connected to the tip of the connecting pipe 66. The volume of the exhaust resonator 67 can be adjusted by effectively utilizing the empty space on the opposite side of the center line C from the primary catalyst 68.

[0034] In addition, in this embodiment, the exhaust resonator is connected to the left exhaust pipe, but the exhaust resonators may be connected to the left and right exhaust pipes. For example, as shown in a third modified example in Fig. 8, the left and right exhaust pipes 71L, 71R may be connected via an exhaust resonator 72, and the inner space of the exhaust resonator 72 may be divided into any volume by a partition wall 73. This allows one exhaust resonator 72 to be used by multiple exhaust pipes 71L, 71R (cylinders).

[0035] In this embodiment, the exhaust resonator is formed in a straight pipe shape, but the shape of the exhaust resonator is not particularly limited. For example, as shown in the fourth modified example of Fig. 9, a plate material 75 bent by pressing may be attached to the outer peripheral surface of the exhaust pipe 76, thereby forming an exhaust resonator 77 by the outer peripheral surface of the exhaust pipe 76 and the plate material 75. In particular, by attaching the plate material 75 to the back surface of the exhaust pipe 76, the empty space on the back surface side of the exhaust pipe 76 can be used for the exhaust resonator 77.

[0036] In addition, in the present embodiment, the engine is an in-line two-cylinder engine, but the type of engine is not particularly limited, and the engine may be a single-cylinder engine or a multi-cylinder engine having two or more cylinders. In the case of a multi-cylinder engine, an exhaust resonator with a different volume for each cylinder may be provided.

[0037] In this embodiment, the left exhaust pipe is shorter than the right exhaust pipe, but the right exhaust pipe may be shorter than the left exhaust pipe. In this case, an exhaust resonator may be connected to the right exhaust pipe.

[0038] Further, in this embodiment, the exhaust resonator extends along the left and right extending portions of the right exhaust pipe, but the exhaust resonator may intersect with the left and right extending portions of the right exhaust pipe.

[0039] Further, in this embodiment, the exhaust resonator is positioned above and to the rear of the right exhaust pipe, but the positional relationship between the exhaust pipe and the exhaust resonator is not particularly limited.

[0040] Furthermore, in this embodiment, the exhaust system is provided with a primary catalyst and a secondary catalyst, but it is sufficient that the exhaust system is provided with at least one catalyst.

[0041] The exhaust system of the present embodiment may be used not only in the engine of the saddle-ride vehicle described above, but also in engines of other types of saddle-ride vehicles. The saddle-ride vehicle is not limited to a motorcycle, but may be any vehicle equipped with an engine. The saddle-ride vehicle is not limited to vehicles in general on which the rider sits astride the seat, but also includes scooter-type vehicles on which the rider does not sit astride the seat.

[0042] As described above, the exhaust system (40) of this embodiment is an exhaust system that purifies exhaust gas discharged from the exhaust ports (31L, 31R) of the engine (20), and includes an exhaust pipe (41L, 41R) into which exhaust gas flows from the exhaust ports of the engine, a catalyst (primary catalyst 45) disposed in front of the engine downstream of the exhaust pipe, and an exhaust resonator (42) connected to the exhaust pipe (41L) upstream of the catalyst. With this configuration, even if the exhaust pipe is shortened by bringing the catalyst closer to the exhaust port to improve the warm-up performance of the catalyst, exhaust pulsation can be adjusted by the exhaust resonator connected to the exhaust pipe. Therefore, a decrease in engine output due to improved warm-up performance of the catalyst can be suppressed without changing the length of the exhaust pipe.

[0043] In the exhaust system of this embodiment, the catalyst is disposed on one side of the center line (C) extending in the vertical direction of the vehicle in the vehicle width direction, and the exhaust resonator is connected to the exhaust pipe on that side. With this configuration, the catalyst is disposed on one side of the center line, and free space is secured on the other side. The free space can be effectively utilized to adjust the volume of the exhaust resonator.

[0044] In the exhaust system of this embodiment, the exhaust pipe is a plurality of exhaust pipes, and the exhaust resonator is disposed between adjacent exhaust pipes. With this configuration, the volume of the exhaust resonator can be adjusted by effectively utilizing the existing free space in front of the engine. Also, the influence of the exhaust resonator on the layout of other components can be minimized.

[0045] In the exhaust system of this embodiment, the exhaust pipe is a plurality of exhaust pipes of different lengths, and the exhaust resonator is connected to the shortest exhaust pipe. With this configuration, even if a large deviation in exhaust pulsation occurs due to a difference in the exhaust pipe length, the deviation in exhaust pulsation can be corrected by the exhaust resonator.

[0046] In the exhaust system of this embodiment, the exhaust pipes are exhaust pipes on one side and the other side in the vehicle width direction across the center line, the other side exhaust pipe extends in the vehicle width direction to one side, and the exhaust resonator extends from the exhaust pipe on one side to the other side along the exhaust pipe on the other side. With this configuration, the exhaust pipe length of the other side exhaust pipe can be secured, while the exhaust resonator connected to the exhaust pipe on one side can adjust the exhaust pulsation. In addition, by extending the exhaust resonator in the vehicle width direction, it is easy to secure the required volume, and by arranging the exhaust resonator along the exhaust pipe on the other side, the exhaust resonator can be made less noticeable, improving the appearance.

[0047] In the exhaust system of this embodiment, the exhaust resonator is located above the exhaust pipe on the other side, and extends from the exhaust pipe on one side to the exhaust port on the other side when viewed from the front. With this configuration, the volume of the exhaust resonator can be adjusted by effectively utilizing the empty space between the exhaust pipe on one side and the exhaust pipe on the other side. In addition, since the exhaust resonator is located above the other exhaust pipe, the catalyst can be brought closer to the exhaust port, and the catalyst does not interfere with the front wheels.

[0048] In the exhaust system of this embodiment, the exhaust resonator is located behind the other exhaust pipe. With this configuration, the exhaust resonator is hidden behind the other exhaust pipe, improving the appearance. In addition, contact between the rider and the exhaust resonator is avoided, ensuring safety. Since the exhaust resonator is surrounded by the exhaust pipe, the exhaust resonator can be protected from external impacts and the like.

[0049] Although the present embodiment has been described, other embodiments may be made by combining the above-described embodiments and modifications in whole or in part.

[0050] In addition, the technology of the present invention is not limited to the above examples, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to the progress of technology or a different technology derived therefrom, the invention may be implemented using that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0051] 20: Engine 31L: Exhaust port 31R: Exhaust port 40: Exhaust system 41L: Exhaust pipe 41R: Exhaust pipe 42: Exhaust resonator 45: Primary catalyst (catalyst)

Claims

1. An exhaust device that purifies exhaust gas discharged from an exhaust port of an engine, an exhaust pipe into which exhaust gas flows from an exhaust port of the engine; a catalyst disposed downstream of the exhaust pipe and forward of the engine; an exhaust resonator connected to the exhaust pipe upstream of the catalyst; The catalyst is disposed on one side in a vehicle width direction from a center line extending in a vertical direction of the vehicle, and the exhaust resonator is connected to the exhaust pipe on the one side. The exhaust pipes are exhaust pipes on one side and the other side in a vehicle width direction across a center line, an exhaust pipe on the other side extending in a vehicle width direction on one side, and an exhaust resonator extending from the exhaust pipe on one side along the exhaust pipe on the other side to the other side,

2. An exhaust device as described in claim 1, characterized in that the exhaust resonator is arranged between the exhaust pipes on one side and the exhaust pipes on the other side.

3. An exhaust device as described in claim 1 or claim 2, characterized in that the exhaust pipe on one side is formed shorter than the exhaust pipe on the other side.

4. 4. The exhaust system according to claim 1, wherein the exhaust resonator is located above the other exhaust pipe and extends from the one exhaust pipe to an exhaust port on the other side when viewed from the front.

5. 5. The exhaust system according to claim 1, wherein the exhaust resonator is located rearward of the other exhaust pipe.

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