Straddle-type vehicle

Abstract

To provide a straddle-type vehicle suitable for running with combustion energy of gas fuel.SOLUTION: A straddle-type vehicle runs with gas fuel. The straddle-type vehicle is provided with a gas tank (61) in which the gas fuel is stored; an engine (41) configured to operate with combustion energy of the gas fuel; an exhaust system component (56) through which exhaust gas discharged from the engine flows; and a relief valve (67) configured to open when pressure of the gas fuel increases to a predetermined pressure or more. The exhaust system component is disposed at one side in the vehicle width direction, and the relief valve is disposed with a discharge port (68) oriented downward at the other side in the vehicle width direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a saddle-type vehicle. [Background technology]

[0002] In recent years, fuel cell vehicles that run on electricity generated by fuel cells have been developed. In fuel cell vehicles, hydrogen gas in a hydrogen tank and oxygen in the air undergo a chemical reaction in the fuel cell to generate electricity, and the generated electricity is supplied to a motor to drive the wheels. As this type of fuel cell vehicle, one equipped with a relief valve that releases hydrogen gas when the pressure in the gas flow path rises above a predetermined pressure is known (see, for example, Patent Document 1). In addition to fuel cell vehicles, vehicles equipped with a gas fuel engine that burns hydrogen gas as gas fuel in the engine and runs using the combustion energy have also been developed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-235099 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in gas-fueled engines, the detailed structure of the gas fuel supply path from the gas tank to the engine has not been fully considered. For example, like fuel cell vehicles, gas-fueled engines are also provided with relief valves, but unlike fuel cell vehicles, gas-fueled engines are provided with exhaust system components. Since the exhaust system components become hot, depending on the location of the relief valve, there is a risk that gas fuel will be sprayed from the relief valve onto the hot exhaust system components.

[0005] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a saddle-type vehicle suitable for running using the combustion energy of gas fuel. [Means for solving the problem]

[0006] One embodiment of the saddle-type vehicle of the present invention is a saddle-type vehicle that runs on gas fuel, and is equipped with a gas tank for storing the gas fuel, an engine that is powered by the combustion energy of the gas fuel, exhaust system components through which exhaust gas discharged from the engine flows, and a relief valve that opens when the pressure of the gas fuel rises above a predetermined pressure, and the above-mentioned problem is solved by having the exhaust system components installed on one side in the vehicle width direction and the relief valve installed on the other side in the vehicle width direction with its outlet facing downward. Effect of the Invention

[0007] According to a straddle-type vehicle of one aspect of the present invention, the exhaust system components and the outlet of the relief valve are spaced apart in the vehicle width direction. Even if gaseous fuel is discharged downward from the outlet of the relief valve, the gaseous fuel is less likely to come into contact with the hot exhaust system components, thereby improving the safety of the vehicle. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a left side view of the vehicle internal structure of the present embodiment. [Diagram 2] FIG. 2 is a right side view of the vehicle internal structure of the present embodiment. [Diagram 3] FIG. 2 is a left side view of the center portion of the vehicle body of the present embodiment. [Figure 4] FIG. 2 is a right side view of the center portion of the vehicle body of the present embodiment. [Diagram 5] FIG. 2 is a left side view of the periphery of the relief valve of the present embodiment. [Figure 6] FIG. 4 is a bottom view of the periphery of the relief valve of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A saddle-type vehicle according to one embodiment of the present invention runs on gas fuel. The gas fuel is stored in a gas tank, and the engine is operated by the combustion energy of the gas fuel. Exhaust system components are installed on one side in the vehicle width direction, and exhaust gas discharged from the engine flows through the exhaust system components. A relief valve is installed on the other side in the vehicle width direction with its outlet facing downward, and the relief valve opens when the pressure of the gas fuel rises to or above a predetermined pressure. Since the exhaust system components and the outlet of the relief valve are separated in the vehicle width direction, even if the gas fuel is discharged downward from the outlet of the relief valve, the gas fuel is less likely to come into contact with the high-temperature exhaust system components, improving the safety of the vehicle. EXAMPLES

[0010] Hereinafter, a saddle-type vehicle of this embodiment will be described with reference to the accompanying drawings. Fig. 1 is a left side view of the internal structure of the vehicle of this embodiment. Fig. 2 is a right side view of the internal structure of the vehicle of this 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] As shown in Figures 1 and 2, a saddle-type vehicle 1 is configured by mounting various covers (not shown) as the exterior of the vehicle body to a body frame 10 made of steel or aluminum alloy. A head pipe 11 is provided at the front end of the body frame 10, and a support frame 12 extends diagonally rearward and downward from an upper portion of the head pipe 11. A pair of first down frames 13 branch off to the left and right and extend downward from a lower portion of the support frame 12, and a pair of second down frames 14 branch off to the left and right and extend downward from a lower portion of the head pipe 11. A pair of main frames 15 are connected to the lower portions of the pair of first and second down frames 13, 14.

[0012] The pair of main frames 15 extend toward the rear of the vehicle, and their middle portions are connected by an upper bridge 16. A pair of asymmetrical side frames 17 extend downward from the front ends of the pair of main frames 15. Each side frame 17 is bent rearward under the vehicle and then extends diagonally upward and rearward toward the rear portions of the pair of main frames 15. The pair of main frames 15 and the pair of side frames 17 form the front half of the body frame 10 into a cradle shape. A pair of footboards 18 are attached to the pair of side frames 17.

[0013] A pair of seat frames 19 extend rearward from the rear portions of the pair of main frames 15. The distance between the pair of seat frames 19 increases toward the middle of each frame and then decreases toward the rear ends of each frame. The pair of seat frames 19 are formed in an arch shape, and the rear ends of the pair of seat frames 19 are connected to each other. The front portions of the pair of seat frames 19 are connected by an upper bridge 21. The rear portions of the pair of side frames 17 are connected to the upper bridge 21, and the upper bridge 21 is supported from below by the pair of side frames 17.

[0014] A pair of asymmetric lower frames 22 extend rearward from the lower portions of the pair of side frames 17. The rear ends of the pair of lower frames 22 are connected by a lower bridge 23. A left subframe 28 extends diagonally upward and rearward from the left end of the lower bridge 23, and the left subframe 28 supports the seat frame 19 from below. A side bridge 25 connects the right end of the lower bridge 23 to an intermediate portion of the right side frame 17. A right subframe 29 extends diagonally upward and rearward from the intermediate portion of the side bridge 25, and the right subframe 29 supports the seat frame 19 from below.

[0015] A front fork 33 is supported on the head pipe 11 so as to be steerable, and a front wheel 34 is supported rotatably on the lower part of the front fork 33. A gas tank 61 is installed inside a cradle portion in the front half of the body frame 10, and a tank valve 63 is installed on the rear end part of the gas tank 61. Gas fuel such as hydrogen is stored in the gas tank 61, and the inflow and outflow of the gas fuel is controlled by the tank valve 63. The gas fuel is supplied from the tank valve 63 to an injector (not shown) above the unit swing engine 41 via gas fuel supply system parts such as multiple pipes and a fuel hose 71.

[0016] A unit swing engine (engine) 41 is supported swingably on the support plates 31 of the left and right subframes 28, 29. The unit swing engine 41 is operated by combustion energy of gas fuel supplied from a gas tank 61. The cylinder axis of the unit swing engine 41 is tilted forward and close to horizontal, and a cylinder assembly 43 extends toward the front of the vehicle from a crankcase 42. The cylinder assembly 43 is inserted between the left subframe 28 and the right subframe 29, and the front end of the cylinder assembly 43 is brought close to a tank valve 63 of the gas tank 61.

[0017] Intake system parts such as an air cleaner 51 are connected to the upper part of the cylinder assembly 43, and exhaust system parts such as an exhaust pipe 56 and a muffler 58 are connected to the lower part of the cylinder assembly 43. A CVT cover 47 is attached to the left side of the crankcase 42. The rear wheel 35 is rotatably supported at the rear part of the CVT cover 47. A belt-type continuously variable transmission (not shown) is housed inside the CVT cover 47, and the driving force of the unit swing engine 41 is transmitted to the rear wheel 35 via the belt. The muffler 58, CVT cover 47, rear wheel 35, and unit swing engine 41 are all swung together.

[0018] Incidentally, in the saddle riding type vehicle 1 that runs on gas fuel, a relief valve 67 is provided that injects gas fuel below the vehicle body in order to suppress a pressure rise in the gas fuel supply system components when the tank valve 63 of the gas tank 61 is damaged and cannot be closed. At this time, the exhaust system components such as the exhaust pipe 56 and the muffler 58 become hot, so it is necessary to prevent the gas fuel injected from the relief valve 67 from splashing on the exhaust system components. Therefore, in this embodiment, the exhaust system components are provided on one side in the vehicle width direction of the saddle riding type vehicle 1, and the relief valve 67 is provided on the other side in the vehicle width direction of the saddle riding type vehicle 1.

[0019] The peripheral structure of the unit swing engine will be described with reference to Figures 3 and 4. Figure 3 is a left side view of the center part of the vehicle body of this embodiment. Figure 4 is a right side view of the center part of the vehicle body of this embodiment. Note that Figures 3 and 4 omit the body frame.

[0020] 3 and 4, the cylinder assembly 43 of the unit swing engine 41 is formed by stacking a cylinder 44, a cylinder head 45, and a cylinder head cover 46. An air cleaner 51 is installed above the cylinder head 45. The air cleaner 51 is connected to an intake port at the top of the cylinder head 45 via a U-shaped outlet tube 52, a throttle body 53, and an intake pipe 54. Air is sent from the air cleaner 51 to the throttle body 53 via the outlet tube 52, and after the intake amount is adjusted by the throttle body 53, the air is supplied to the cylinder head 45 through the intake pipe 54.

[0021] An exhaust pipe 56 is connected to the exhaust port at the bottom of the cylinder head 45. A bent portion 57 that curves rearward from the cylinder head 45 is formed in the exhaust pipe 56, and the downstream side of the bent portion 57 of the exhaust pipe 56 passes to the right side of the crankcase 42 and extends toward the rear of the vehicle. A muffler 58 (see FIG. 2) that is inclined diagonally upward and rearward on the right side of the rear wheel 35 is connected to the rear end of the exhaust pipe 56. Exhaust gas discharged from the unit swing engine 41 flows through the exhaust pipe 56 and muffler 58, which are exhaust system components, and the exhaust gas warms the exhaust pipe 56 and muffler 58 to a high temperature.

[0022] A link mechanism (mounting member) 37 for mounting the suspension 36 to the vehicle body is provided below the cylinder head 45. The link mechanism 37 is provided with a link lever 38 that is arc-shaped in side view, and an intermediate portion of the link lever 38 is swingably connected to a bracket 32 ​​(see FIG. 5) of the vehicle body frame 10 (lower bridge 23). A lower portion of the crankcase 42 is swingably connected to an upper end of the link lever 38 via a link arm 39, and a rear end of the suspension 36 is swingably connected to a lower end of the link lever 38. The suspension 36 expands and contracts in accordance with the swing of the unit swing engine 41, thereby absorbing vibrations transmitted to the vehicle body.

[0023] A gas tank 61 is installed in front of the unit swing engine 41. The gas tank 61 is formed in a cylindrical shape, and both ends of the gas tank 61 are bulged out in a hemispherical shape. The longitudinal direction of the gas tank 61 is directed forward and backward, and the gas tank 61 is slightly tilted so that the front end of the gas tank 61 is higher than the rear end. A tank valve 63 is installed at the rear end of the gas tank 61, and a pipe joint 65 is connected to a relief valve pipe 64 that extends diagonally upward and rearward from the lower part of the tank valve 63. Therefore, the pipe joint 65 is positioned in the space between the tank valve 63 and the cylinder head 45 in a side view.

[0024] A pressure sensor 66 is attached to the upper part of the pipe joint 65, and a relief valve 67 is attached to the lower part of the pipe joint 65. The pressure in the gas flow path is detected by the pressure sensor 66, and when the pressure of the gas fuel rises to or exceeds a predetermined pressure, the relief valve 67 is opened. The gas fuel is released toward the ground from a downward-facing outlet 68 (see FIG. 6) of the relief valve 67. As will be described in detail later, the pipe joint 65 is positioned on the left side of the vehicle body (the other side in the vehicle width direction), so that the gas fuel released from the relief valve 67 is less likely to get into the exhaust pipe 56 on the right side of the vehicle body.

[0025] An injector joint 91 is connected to the pipe joint 65 via an upstream pipe 69, a fuel hose 71, and a downstream pipe 72. The upstream pipe 69 and the downstream pipe 72 are formed of a hard pipe material such as metal, and the fuel hose 71 is formed of a soft rubber hose. The upstream pipe 69 crosses below the tank valve 63 and extends from the pipe joint 65 on the left side of the vehicle body to the right side of the vehicle body. On the right side of the vehicle body, the lower end of the fuel hose 71 is connected to the upstream pipe 69, and the fuel hose 71 extends upward through the right side of the gas tank 61. The upper end of the fuel hose 71 is connected to the injector joint 91 above the cylinder head 45 via the downstream pipe 72.

[0026] In this way, a gas flow path from the gas tank 61 to the unit swing engine 41 is formed by the relief valve pipe 64, the pipe joint 65, the upstream piping 69, the fuel hose 71, and the downstream piping 72. Because a part of the gas flow path is formed by the fuel hose 71, the unit swing engine 41 is allowed to swing due to bending deformation of the fuel hose 71. By attaching the relief valve 67 to the pipe joint 65, the relief valve 67 is interposed in the middle of the gas flow path. This increases the degree of freedom in installing the relief valve 67, and allows the relief valve 67 to be installed in a safer location.

[0027] As described above, the pipe joint 65 has an attachment portion for the pressure sensor 66, an attachment portion for the relief valve 67, a connection portion for the relief valve pipe 64, and a connection portion for the upstream piping 69 (fuel hose 71) formed integrally therewith. By forming each attachment portion and each connection portion in the pipe joint 65, the pressure sensor 66 and the relief valve 67 are installed compactly and the relief valve pipe 64 and the upstream piping 69 are connected compactly. The pipe joint 65 is supported via the bracket 27 on the side bridge 26 (see FIG. 5 ) that connects the side frame 17 on the left side of the vehicle body and the left subframe 28.

[0028] A PCV valve 81 is provided on the cylinder head cover 46, and the intake pipe 54 is connected to the PCV valve 81 via a PCV hose 82 (see FIG. 4 in particular). The PCV valve 81 opens when the intake pipe 54 becomes negative pressure. Blow-by gas in the cylinder head cover 46 is returned to the intake pipe 54 through the PCV hose 82, and is sent to the intake port of the cylinder head 45 and re-burned. Because the PCV hose 82 is made of a soft rubber hose, bending deformation of the PCV hose 82 allows the unit swing engine 41 to swing.

[0029] The layout of the relief valve will be described with reference to Figures 5 and 6. Figure 5 is a left side view of the relief valve and its periphery in this embodiment. Figure 6 is a bottom view of the relief valve and its periphery in this embodiment.

[0030] 5 and 6, the tank valve 63 of the gas tank 61 is positioned in front of the relief valve 67, and the cylinder head 45 of the unit swing engine 41 is positioned behind the relief valve 67. The suspension 36 is positioned below the gas tank 61, and the link lever 38 is positioned below the cylinder head 45. The front end of the suspension 36 is connected to the front lower bridge 24, and the rear end of the suspension 36 is connected to the rear lower bridge 23 via the link lever 38. An exhaust pipe 56 extends from the lower part of the cylinder head 45, curving rearward.

[0031] In bottom view, the exhaust pipe 56 extends rearward to the right from the cylinder head 45, and the relief valve 67 is supported by the left side bridge 26 via the bracket 27. That is, the exhaust system components are disposed to the right of the vehicle body center line C extending in the front-rear direction of the vehicle body, and the relief valve 67 is disposed to the left of the vehicle body center line C. In addition, the outlet 68 of the relief valve 67 is located forward of the bent portion 57 of the exhaust pipe 56. Since the exhaust pipe 56 and the relief valve 67 are separated in the left-right direction and the outlet 68 is located forward of the bent portion 57 at the front end of the exhaust pipe 56, the gas fuel discharged from the relief valve 67 is less likely to get into the exhaust pipe 56.

[0032] In a side view, the relief valve 67 is located between the tank valve 63 and the bent portion 57 of the exhaust pipe 56, and the outlet 68 of the relief valve 67 is positioned at the same height as the lower surface of the bent portion 57. Since the gas fuel is released downward from the outlet 68 of the relief valve 67, the bent portion 57 is out of the gas fuel release range, making it difficult for the gas fuel to directly hit the high-temperature bent portion 57. Note that the outlet 68 of the relief valve 67 and the lower surface of the bent portion 57 being at the same height does not necessarily mean that the outlet 68 of the relief valve 67 and the lower surface of the bent portion 57 are at exactly the same height, but it is sufficient that the outlet 68 of the relief valve 67 and the lower surface of the bent portion 57 are at approximately the same height.

[0033] Moreover, in bottom view, the exhaust pipe 56 is disposed to the right of the suspension 36, and the relief valve 67 is disposed to the left of the suspension 36. Even if gas fuel is released from an outlet 68 of the relief valve 67, the gas fuel is partially blocked by the suspension 36, making it difficult for the gas fuel to reach the exhaust pipe 56. In this case, the suspension 36 is disposed to the right of the vehicle body center line C. By bringing the suspension 36 closer to the relief valve 67, the gas fuel flowing from the relief valve 67 toward the right side of the vehicle body is effectively blocked by the suspension 36.

[0034] In a side view, the bent portion 57 of the exhaust pipe 56 is covered by the link lever 38 (mounting member) and the link arm 39 from the inside in the vehicle width direction. In addition, in a side view, the link lever 38 is located forward of the bent portion 57 of the exhaust pipe 56, and the outlet 68 of the relief valve 67 is located forward of the link lever 38. In other words, in a bottom view, the link lever 38 is located on a straight line L connecting the outlet 68 of the relief valve 67 and the bent portion 57 of the exhaust pipe 56. As a result, the gas fuel flowing from the outlet 68 of the relief valve 67 toward the bent portion 57 is blocked by the link lever 38 and the link arm 39, making it difficult for it to reach the bent portion 57 of the exhaust pipe 56.

[0035] As described above, according to the saddle riding type vehicle 1 of this embodiment, the exhaust pipe 56 and the relief valve 67 are separated in the left-right direction. Even if gaseous fuel is discharged downward from the discharge port 68 of the relief valve 67, the gaseous fuel is less likely to come into contact with the high-temperature exhaust pipe 56, improving the safety of the vehicle.

[0036] In this embodiment, the exhaust pipe is installed on the right side of the vehicle body and the relief valve is installed on the left side of the vehicle body, but the exhaust pipe may be installed on the left side of the vehicle body and the relief valve may be installed on the right side of the vehicle body.

[0037] In addition, in this embodiment, a unit swing engine is exemplified as the engine, but the engine is not limited to a unit swing engine as long as it is operated by the combustion energy of gas fuel.

[0038] Further, in this embodiment, the engine is a hydrogen engine using hydrogen gas, but it may be another gas fuel engine using other gas fuel such as methane gas or propane gas.

[0039] Further, in this embodiment, the cylinder axis of the unit swing engine is inclined forward and close to horizontal, but the cylinder axis of the unit swing engine may be horizontal.

[0040] Further, in this embodiment, a single gas tank is provided in the saddle riding type vehicle, but a plurality of gas tanks may be provided in the saddle riding type vehicle.

[0041] In addition, in this embodiment, the gas tank is formed in a cylindrical shape with both ends bulging out into a hemisphere, but the shape of the gas tank is not limited as long as the gas tank has a shape capable of storing gas fuel.

[0042] In the present embodiment, the relief valve is provided at the pipe joint, but the relief valve may be provided anywhere in the fuel gas flow path. The relief valve may also be provided at the tank valve.

[0043] The layout of the relief valve in this embodiment is not limited to the above-mentioned saddle-ride type vehicle, and may be adopted in other types of saddle-ride type vehicles. Note that the saddle-ride type vehicle is not limited to all vehicles in which the rider sits astride the seat, but also includes scooter-type vehicles in which the rider does not sit astride the seat.

[0044] As described above, the first embodiment is a saddle-type vehicle (1) that runs on gas fuel, and includes a gas tank (61) that stores gas fuel, an engine (unit swing engine 41) that operates by the combustion energy of the gas fuel, exhaust system components (exhaust pipe 56) through which exhaust gas discharged from the engine flows, and a relief valve (67) that opens when the pressure of the gas fuel rises to a predetermined pressure or higher, and the exhaust system components are installed on one side in the vehicle width direction, and the relief valve is installed on the other side in the vehicle width direction with its outlet (68) facing downward. With this configuration, the exhaust system components and the outlet of the relief valve are separated in the vehicle width direction. Even if the gas fuel is discharged downward from the outlet of the relief valve, the gas fuel is less likely to come into contact with the high-temperature exhaust system components, improving the safety of the vehicle.

[0045] In the second aspect, in the first aspect, the exhaust system component has a bent portion (57) that curves rearward from the engine, and the outlet of the relief valve is located forward of the bent portion. With this configuration, the outlet of the relief valve is located forward of the bent portion at the front end of the exhaust system component, so that even if gas fuel is released from the outlet of the relief valve, the gas fuel is less likely to get into the exhaust pipe.

[0046] In the third aspect, in the second aspect, the outlet of the relief valve is at the same height as the lower surface of the bent portion. With this configuration, the gas fuel is discharged downward from the outlet of the relief valve, so that the bent portion is out of the range of the gas fuel discharge, making it difficult for the gas fuel to directly contact the bent portion.

[0047] A fourth aspect is any one of the first to third aspects, further comprising a suspension (36) that absorbs vibrations transmitted to the vehicle body, the exhaust system components are disposed on one side of the suspension in the vehicle width direction, and the relief valve is disposed on the other side of the suspension in the vehicle width direction. With this configuration, even if gas fuel is discharged from the outlet of the relief valve, the gas fuel is blocked by the suspension and is less likely to get on the exhaust system components.

[0048] In the fifth aspect, in the fourth aspect, a mounting member (link lever 38) for mounting the suspension to the vehicle body is provided, and the exhaust system components are covered by the mounting member from the inside in the vehicle width direction in a side view. With this configuration, even if gas fuel is discharged from the outlet of the relief valve, the gas fuel heading toward the exhaust system components from the inside in the vehicle width direction is blocked by the mounting member, making it difficult for it to get on the exhaust system components.

[0049] In a sixth aspect, in the fourth or fifth aspect, a mounting member for mounting the suspension to the vehicle body is provided, the mounting member is located forward of the exhaust system components in a side view, and the outlet of the relief valve is located forward of the mounting member. With this configuration, even if gas fuel is released from the outlet of the relief valve, the gas fuel heading toward the exhaust system components from the front is blocked by the mounting member, making it difficult for it to get on the exhaust system components.

[0050] A seventh aspect is any one of the first to sixth aspects, in which a gas flow path extends from the gas tank to the engine, and a relief valve is interposed in the middle of the gas flow path. According to this configuration, compared to a configuration in which the relief valve is attached to a tank valve of the gas tank, the degree of freedom in installing the relief valve is increased, and the relief valve can be installed in a safer location.

[0051] 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.

[0052] 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]

[0053] 1: Saddle-type vehicle 36: Suspension 37: Link mechanism (mounting member) 41: Unit Swing Engine (Engine) 56: Exhaust pipe (exhaust system parts) 57: Bending section 61: Gas tank 67: Relief valve 68: Outlet

Claims

1. A saddle-type vehicle that runs on gas fuel, A gas tank for storing gas fuel; an engine operated by the combustion energy of gas fuel; an exhaust system component through which exhaust gas discharged from the engine flows; a relief valve that opens when the pressure of the gas fuel rises to or exceeds a predetermined pressure; 13. A saddle-type vehicle, wherein the exhaust system components are disposed on one side in a vehicle width direction, and the relief valve is disposed on the other side in the vehicle width direction with its outlet facing downward.

2. the exhaust system component has a bent portion that curves rearward from the engine, 2. The straddle-type vehicle according to claim 1, wherein the relief valve has an outlet located forward of the bent portion.

3. 3. The straddle-type vehicle according to claim 2, wherein the outlet of the relief valve is at the same height as a lower surface of the bent portion.

4. Equipped with a suspension that absorbs vibrations transmitted to the vehicle body, the exhaust system component is disposed on one side of the suspension in a vehicle width direction, 3. The straddle-type vehicle according to claim 1, wherein the relief valve is disposed on the other side of the suspension in the vehicle width direction.

5. A mounting member is provided for mounting the suspension to a vehicle body, 5. The straddle-type vehicle according to claim 4, wherein the exhaust system component is covered by the mounting member from an inner side in the vehicle width direction in a side view.

6. A mounting member is provided for mounting the suspension to a vehicle body, The mounting member is located forward of the exhaust system component in a side view, 5. The straddle-type vehicle according to claim 4, wherein the outlet of the relief valve is located forward of the mounting member.

7. A gas flow path extends from the gas tank toward the engine, 3. The straddle-type vehicle according to claim 1, wherein the relief valve is disposed midway along the gas flow passage.

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