Vehicle and exhaust component

Abstract

To prevent unburned gas included in exhaust gas of a lightweight fuel gas internal combustion engine from staying in an exhaust component.SOLUTION: A vehicle comprises a lightweight fuel gas internal combustion engine and an exhaust component. The lightweight fuel gas internal combustion engine outputs a driving force obtained by burning lightweight gas fuel that is lighter than air. The exhaust component is connected to an exhaust pipe of the lightweight fuel gas internal combustion engine. The exhaust component includes a housing that bulges at least more upward than the exhaust pipe. An unburned gas outlet connecting an upper part of an internal space of the housing to an external space at a higher position is provided in the exhaust component.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to exhaust from a light fuel gas internal combustion engine in a vehicle having such an engine. [Background technology]

[0002] Patent Document 1 discloses a moving body that obtains propulsion energy by receiving a supply of gas containing hydrogen. A pipe is formed in a passage for exhaust gas from an energy source to discharge water generated with the generation of energy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-137505 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although a pipe for discharging water is formed in the exhaust gas passage of Patent Document 1, there are cases in which exhaust gas is not sufficiently discharged.

[0005] The present disclosure has been made in view of the above circumstances, and has an object to enhance exhaust gas discharge from exhaust components in a light fuel gas internal combustion engine. [Means for solving the problem]

[0006] The problem to be solved by the present disclosure is as described above. Next, the means for solving this problem and the effects thereof will be described.

[0007] According to a first aspect of the present disclosure, there is provided a vehicle having the following configuration. That is, the vehicle includes a lightweight fuel gas internal combustion engine and an exhaust component. The lightweight fuel gas internal combustion engine outputs a driving force obtained by burning a lightweight gas fuel that is lighter than air. The exhaust component is connected to an exhaust pipe of the lightweight fuel gas internal combustion engine. The exhaust component includes a housing that bulges at least upwardly from the exhaust pipe. The exhaust component is provided with an unburned gas outlet that connects an upper portion of an internal space of the housing with an external space at a higher position.

[0008] According to a second aspect of the present disclosure, there is provided an exhaust part having the following configuration. That is, this exhaust part is used in a vehicle equipped with a lightweight fuel gas internal combustion engine that outputs driving force obtained by burning a lightweight gas fuel that is lighter than air. The exhaust part is connected to an exhaust pipe of the lightweight fuel gas internal combustion engine. The exhaust part includes a housing that bulges at least upward from the exhaust pipe. The exhaust part is provided with an unburned gas outlet that connects an upper portion of an internal space of the housing with an external space at a higher position.

[0009] As a result, the unburned gas contained in the gas discharged from the internal combustion engine moves from the exhaust pipe to the upper space in the housing due to a buoyancy effect. The unburned gas in the housing moves to the outside of the housing through the unburned gas outlet. This can promote the discharge of exhaust gas from exhaust components, for example, the housing, through the unburned gas outlet. By promoting exhaust in this way, for example, it can prevent the exhaust gas containing unburned gas from accumulating in the housing. Effect of the Invention

[0010] The present disclosure provides for enhanced emission of exhaust gases from exhaust components in light fuel gas internal combustion engines. [Brief description of the drawings]

[0011] [Figure 1] 1 is a side view showing an overall configuration of a motorcycle according to an embodiment of the present disclosure. [Diagram 2]FIG. 1 is a perspective view showing a muffler according to a first embodiment. [Diagram 3] FIG. 4 is a perspective view showing a muffler according to a second embodiment. [Figure 4] FIG. 11 is a perspective view showing a muffler according to a third embodiment. [Diagram 5] FIG. 13 is a perspective view showing a muffler according to a fourth embodiment. [Figure 6] FIG. 13 is a schematic diagram showing a muffler according to a fifth embodiment. [Figure 7] FIG. 13 is a schematic diagram showing a muffler according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a side view showing an overall configuration of a motorcycle 1 according to an embodiment of the present disclosure. Fig. 2 is a perspective view showing a muffler 23 of the first embodiment.

[0013] The motorcycle (saddle-type vehicle, vehicle) 1 of this embodiment includes a frame 3, a front wheel 6, a rear wheel 7, and a steering handle 8. The frame 3, the front wheel 6, the rear wheel 7, and the steering handle 8 form a part of a vehicle body 2.

[0014] A driver drives the motorcycle 1 while straddling the body 2. In the following description, unless otherwise specified, the terms front, rear, left, and right mean the front, rear, left, and right as seen by the driver while riding the motorcycle 1. The left-right direction corresponds to the vehicle width direction, and the front-rear direction corresponds to the vehicle length direction.

[0015] The frame 3 is a strength component that serves as the framework of the vehicle body 2, and is made of, for example, metal pipes. The frame 3 supports an engine (lightweight fuel gas internal combustion engine) 22 that serves as a drive source for propelling the motorcycle 1.

[0016] The engine 22 functions as a power unit that drives the rear wheels 7, which are driving wheels. The engine 22 burns a lightweight gas fuel to rotate a crankshaft (not shown) to obtain power. In this specification, lightweight gas means a gas that is lighter per unit volume than air at room temperature. In this embodiment, hydrogen is used as the fuel for the engine 22, but light gases such as methane and ammonia may also be used. The number of cylinders in the engine 22 is arbitrary, but in this embodiment, a multiple-cylinder engine 22 is used. The driving force generated by the engine 22 is changed in speed by a transmission (not shown) and transmitted to the rear wheels 7 via the drive chain 12.

[0017] A seat 14 for a driver to sit in is provided on the upper part of the vehicle body 2. A steering wheel 8 operated by the driver is provided on the upper front part of the vehicle body 2.

[0018] A head pipe 15 is provided at the front of the frame 3. A front wheel 6 is supported on the head pipe 15 via a front fork 16. The rider can turn the front wheel 6 by operating a steering handle 8. A swing arm 17 is supported at the lower part of the central front-rear portion of the frame 3 so as to protrude rearward. The rear wheel 7 is rotatably supported at the tip of the swing arm 17.

[0019] A gas tank 21 is attached to the rear of the frame 3. Hydrogen gas, which is fuel, is stored in a compressed state in the gas tank 21. In this embodiment, a pair of gas tanks 21 are provided on the left and right, but the number of gas tanks 21 is arbitrary. Each gas tank 21 is formed in a cylindrical shape and is disposed with its axial direction facing the front-rear direction. A fuel supply pipe 26 is connected to the gas tank 21 via a valve device (not shown). Hydrogen gas is supplied from the gas tank 21 to the engine 22 via the fuel supply pipe 26.

[0020] A tank cover 25 is attached to the frame 3 so as to cover the gas tank 21. The tank cover 25 is formed to be hollow, and protects the internal gas tank 21 from external impacts.

[0021] Depending on the layout of each part of the vehicle body 2, other vehicle-mounted parts may be arranged above exhaust parts such as a muffler 23 described later, and a recess that is open downward and recessed upward may be formed in the vehicle-mounted part. Examples of places where such a recess is formed include, but are not limited to, the lower surface of the rear cowl, the bottom surface of the pannier case, and the lower surface of the tank cover 25. Fig. 1 shows an example in which a non-penetrating recess 30 is formed in the lower surface of the tank cover 25.

[0022] The recess may be formed as a through hole formed in the lower surface of a hollow member. Examples of hollow members include, but are not limited to, a tank cover, a rear cowl, a seat cowl, or a pannier case. In this case, the upper part of the internal space of the hollow member is closed, and the internal space and the lower space are connected via the through hole. A small gap connecting the internal space and the upper space may be formed in the hollow member.

[0023] A muffler 23, which is an example of an exhaust component, is disposed on one of the left and right sides of the rear wheel 7. The muffler 23 is connected to the engine 22 via an exhaust pipe 27. Exhaust gas generated by burning hydrogen gas in the engine 22 is discharged to the outside via the exhaust pipe 27 and the muffler 23. A sound absorbing structure is configured inside the muffler 23, which reduces the exhaust noise generated when the exhaust gas is discharged to the outside. In this way, the muffler 23 functions as an exhaust sound absorbing device.

[0024] An expansion chamber is formed inside the muffler 23, where the exhaust gas expands compared to the connected exhaust pipe 27. In this expansion chamber, the cross-sectional area in the direction perpendicular to the exhaust gas flow direction is larger than that of the upstream exhaust pipe 27. The expansion of the exhaust gas in the muffler 23 consumes the energy of the exhaust gas, and as a result, the exhaust noise is silenced. The expansion chamber may be configured so that the expansion is repeated multiple times in the muffler 23, or a resonance structure or a sound-absorbing structure may be used in combination.

[0025] The muffler 23 includes a hollow housing 41. The housing 41 is configured, for example, in an elongated shape, and is disposed so that its longitudinal direction is generally along the front-rear direction in a plan view. The housing 41 is located below one of the pair of tank covers 25 disposed on the left and right.

[0026] As shown in FIG. 2, the exhaust pipe 27 is inserted from the front into the front part of the housing 41. In FIG. 2, the internal structure of the housing 41 is omitted. An exhaust inlet 43 is formed at the rear end of the exhaust pipe 27. The exhaust pipe 27 is connected to the internal space 42 of the housing 41 through the exhaust inlet 43. The axis of the exhaust pipe 27 is inclined upward as it approaches the exhaust inlet 43. An outlet pipe 44 is connected to the rear end of the housing 41, and an exhaust outlet 45 is formed at the rear end of the outlet pipe 44. The exhaust gas introduced from the exhaust pipe 27 into the internal space 42 of the housing 41 through the exhaust inlet 43 flows rearward and is discharged from the exhaust outlet 45 of the outlet pipe 44.

[0027] An expansion chamber (muffling chamber) is formed inside the housing 41. Therefore, the housing 41 is formed to have an outer diameter larger than the exhaust pipe 27 and also larger than the outlet pipe 44. As a result, the housing 41 and its internal space 42 expand at least one of the upper, lower, left, and right directions from the exhaust pipe 27 and the outlet pipe 44. In other words, the exhaust pipe 27 and the outlet pipe 44 are recessed toward the center position of the housing 41 relative to the housing 41. Specifically, the upper surfaces of the exhaust pipe 27 and the outlet pipe 44 are disposed below the upper surface of the housing 41.

[0028] A sound deadening material such as metal wool or glass wool may be placed in the internal space 42 of the housing 41 .

[0029] In this embodiment, a guide pipe 46 is provided at the upper rear part of the housing 41 in addition to the outlet pipe 44. The guide pipe 46 is arranged so as to protrude obliquely upward and rearward from the housing 41. A degassing passage (exhaust passage) 47 is formed inside the guide pipe 46. An unburned gas outlet 48 is formed at the end of the guide pipe 46 farther from the housing 41. The unburned gas outlet 48 is located at the downstream end of the degassing passage 47. The degassing passage 47 and the unburned gas outlet 48 are provided so as to connect an upper part (preferably the top) of the internal space 42 of the housing 41 to an external space at a higher position.

[0030] In this embodiment, the unburned gas outlet 48 is formed to have a smaller passage cross-sectional area than the exhaust outlet 45. The guide pipe 46 protrudes upward from the upper surface of the housing 41. More specifically, the guide pipe 46 protrudes upward from the top surface of the housing 41.

[0031] In motorcycle 1 equipped with hydrogen gas engine 22, unburned hydrogen gas is discharged from engine 22 and may be introduced into muffler 23 through exhaust pipe 27. If hydrogen gas accumulates in internal space 42 of housing 41 in which muffler 23 is provided, the hydrogen gas may burn within muffler 23, causing abnormal noise. In this regard, in this embodiment, hydrogen gas, which is lighter than air, is promoted to be exhausted from the upper part of internal space 42 of housing 41 through unburned gas outlet 48. This makes it possible to prevent unburned hydrogen gas from accumulating in muffler 23 and problems resulting from such accumulation.

[0032] The ceiling surface of the inner wall surfaces constituting the internal space 42 of the housing 41 is inclined from the horizontal so that the downstream side in the direction of exhaust gas flow is higher. For reference, a horizontal imaginary plane H1 is shown in FIG. 2. Due to this inclined arrangement, the unburned hydrogen gas in the internal space 42 flows rearward along the ceiling surface. Therefore, it can be said that the vicinity of the upper part of the rear end of the internal space 42 is a retention part where the unburned hydrogen gas is likely to remain. The unburned gas outlet 48 is configured to guide the unburned hydrogen gas from the upper part of the rear end (the retention part described above) of the internal space 42 of the housing 41 to the external space. Therefore, it is possible to effectively prevent the unburned hydrogen gas from remaining in the upper part of the rear end part of the housing 41. As in the third embodiment described later, the ceiling surface of the inner wall surfaces of the housing 41 may be arranged substantially horizontally.

[0033] The opening area of ​​the exhaust outlet 45 is larger than the opening area of ​​the unburned gas outlet 48. Therefore, it is possible to prevent the flow path resistance of the exhaust outlet 45 from becoming excessively large while preventing the unburned hydrogen gas from stagnation.

[0034] In this embodiment, a pair of tank covers 25 are arranged on the left and right. Therefore, the bottom surface 32 of the tank cover 25 arranged on one of the left and right sides and the unburned gas outlet 48 of the muffler 23 may be arranged to roughly correspond to each other in the up-down direction. In this case, unburned hydrogen gas discharged from the unburned gas outlet 48 may enter the recess 30 of the bottom surface 32 from below, or enter the internal space of the tank cover 25 from below through the through-hole from the bottom surface 32, and may remain there for a long time.

[0035] To prevent this, as shown in Fig. 1, a guide portion 51 is disposed above the unburned gas outlet 48. The guide portion 51 is, for example, a plate-shaped member, and is disposed so as to block the gap between the unburned gas outlet 48 and the tank cover 25. This makes it possible to guide the unburned hydrogen gas so that it does not enter the recess 30 on the lower surface of the tank cover 25 or the inside of the tank cover 25, thereby preventing the unburned hydrogen gas from accumulating in the tank cover 25. In the example of Fig. 1, the guide portion 51 is attached to the frame 3, but it may also be attached, for example, to the upper portion of the muffler 23 or the lower portion of the tank cover 25.

[0036] As described above, the motorcycle 1 of this embodiment includes the engine 22 and the muffler 23. The engine 22 outputs driving force obtained by burning hydrogen gas fuel, which is lighter than air. The muffler 23 is connected to the exhaust pipe 27 of the engine 22. The muffler 23 includes a housing 41 that bulges at least upward from the exhaust pipe 27. The muffler 23 is provided with an unburned gas outlet 48 that connects an upper portion of the internal space 42 of the housing 41 to an external space at a higher position.

[0037] This allows the buoyancy of unburned hydrogen gas to allow it to be discharged from unburned gas outlet 48 without stagnation of unburned hydrogen gas within housing 41 of muffler 23. Therefore, while motorcycle 1 is in operation, discharge of unburned hydrogen gas in muffler 23 is promoted, and stagnation within muffler 23 can be prevented.

[0038] In the motorcycle 1 of this embodiment, the muffler 23 includes a gas vent passage 47 connected to the internal space 42. The gas vent passage 47 is inclined upward as it advances downstream in the exhaust direction. The unburned gas outlet 48 is disposed at the downstream end of the gas vent passage 47.

[0039] As a result, the inclined gas vent passage 47 can be used to smoothly guide the unburned hydrogen gas to the unburned gas outlet 48 and discharged.

[0040] In the present embodiment, in the housing 41, the ceiling surface of the inner wall surfaces that form the internal space 42 is inclined so as to become higher toward the rear. The unburned gas outlet 48 connects an upper part of the ceiling surface to the external space.

[0041] This allows gas that tends to accumulate near the ceiling surface of the housing 41 to be collected at the unburned gas outlet 48 and effectively discharged.

[0042] In the motorcycle 1 of this embodiment, the muffler 23 includes an exhaust outlet 45 that discharges exhaust gas introduced into the muffler 23. The exhaust outlet 45 is formed at a position different from the unburned gas outlet 48.

[0043] As a result, the unburned gas outlet 48 is provided separately from the exhaust outlet 45, which mainly exhausts gas after combustion, so that appropriate outlets can be realized for each, taking into account the differences in the characteristics of the exhausted gas.

[0044] In the motorcycle 1 of this embodiment, the opening area of ​​the exhaust outlet 45 is larger than the opening area of ​​the unburned gas outlet .

[0045] This makes it possible to reduce the flow resistance of the combustion gas at the exhaust outlet 45, thereby maintaining exhaust performance, while preventing the accumulation of unburned hydrogen gas.

[0046] In the motorcycle 1 of this embodiment, a guide portion 51 that guides the unburned hydrogen gas that flows out from the unburned gas outlet 48 into the external space of the housing 41 is provided above the unburned gas outlet 48.

[0047] This makes it possible to prevent the unburned hydrogen gas discharged from the unburned gas outlet 48 from staying in a particular location on the motorcycle 1, for example.

[0048] In the motorcycle 1 of this embodiment, the internal space 42 of the housing 41 is a sound-absorbing chamber that reduces the exhaust noise of the engine 22.

[0049] This makes it possible to prevent unintentional combustion of unburned hydrogen gas in the muffler 23.

[0050] Next, a second embodiment will be described with reference to Fig. 3. In the following description of this embodiment, the same or similar members as those in the previous embodiment are denoted by the same reference numerals in the drawings, and descriptions thereof may be omitted.

[0051] 3, the muffler 23a of this embodiment does not include the outlet pipe 44 and the exhaust outlet 45. The guide pipe 46 is configured to have a large diameter similar to that of the outlet pipe 44 of the first embodiment. In this embodiment, an unburned gas outlet 48 formed in the guide pipe 46 serves as both an outlet for combusted exhaust gas and an outlet for unburned hydrogen gas.

[0052] Even in this configuration, the unburned hydrogen gas remaining in the internal space 42 of the housing 41 can be smoothly discharged from the unburned gas outlet 48.

[0053] Next, a third embodiment will be described with reference to FIG.

[0054] In the muffler 23b of this embodiment shown in Fig. 4, the housing 41 is disposed substantially horizontally. Therefore, among the inner wall surfaces that form the internal space 42 in the housing 41, the ceiling surface is approximately horizontal. In Fig. 4, the housing 41, the guide pipe 46, etc. are drawn see-through with dashed lines to explain the inside of the housing 41.

[0055] Two ring-shaped partitions 49 are provided to divide the internal space 42 of the housing 41 into a plurality of spaces in the longitudinal direction. The longitudinal direction of the housing 41 can also be referred to as the direction in which the exhaust gas flows in the muffler 23b. Each partition 49 is disposed outside the outlet pipe 44, which is disposed elongated as described below. The number of partitions 49 into which the internal space 42 is divided is arbitrary, but in this embodiment, the internal space 42 is divided into three spaces. Hereinafter, the three spaces may be referred to as the first space 42a, the second space 42b, and the third space 42c, in order from the front. Dividing the internal space 42 unequally is preferable because it is possible to effectively suppress noise over a wide range of frequencies.

[0056] A guide pipe 46 is provided on the upper surface of the housing 41. A degassing passage 47 formed in the guide pipe 46 forms an opening in a ceiling surface at the longitudinal center of the housing 41. Therefore, the degassing passage 47 is connected to the second space 42b located at the longitudinal center of the housing 41, among the three spaces divided by the partition 49.

[0057] In the muffler 23b of the present embodiment, the outlet pipe 44 extends forward so as to penetrate the partition 49, and is directly connected to the exhaust pipe 27. A large number of small through holes are formed in a portion of the outlet pipe 44 that is located in the internal space 42 of the housing 41.

[0058] Each partition 49 is disposed so as to form a gap (flow passage) 50 between it and the ceiling surface. This gap 50 connects the partitioned spaces together. As a result, the flow of unburned hydrogen gas introduced into the inside of the housing 41 and floated near the ceiling surface is not blocked by the partitions 49, so that the unburned hydrogen gas can be smoothly guided to the unburned gas outlet 48. In the example of FIG. 4, the gap 50 is configured by forming a flat recess in the uppermost part of the circular outer edge of the partition 49. However, the configuration of the flow passage is not limited to this, and for example, a circular through hole for circulating the unburned hydrogen gas may be formed in the upper part of the partition 49.

[0059] As described above, in the motorcycle 1 of this embodiment, the internal space 42 of the housing 41 is divided into a plurality of spaces (first space 42a, second space 42b, and third space 42c) by the partitions 49. The unburned gas outlet 48 is connected to an upper portion of the second space 42b, which is located in the longitudinal center of the housing 41, among the plurality of spaces. A gap 50 that connects the divided spaces to each other is formed at the upper portion of the partition 49 located between adjacent spaces.

[0060] This allows the unburned hydrogen gas in each of the multiple partitioned spaces to be efficiently discharged from the unburned gas outlet 48.

[0061] Next, a fourth embodiment will be described with reference to FIG.

[0062] 5, a muffler 23c of the present embodiment does not include the outlet pipe 44 and the exhaust outlet 45. As in the third embodiment, the internal space 42 of the housing 41 is divided by two partitions 49 to form a first space 42a, a second space 42b, and a third space 42c.

[0063] An exhaust inlet 43, which is the downstream end of the exhaust pipe 27, is located in the first space 42a, which is the frontmost space of the three spaces. The rear end of the housing 41 is closed.

[0064] A cylindrical first passing pipe 53 is disposed inside the housing 41 so as to penetrate the two partitions 49. An opening on one side of the first passing pipe 53 is located in the first space 42a, and an opening on the opposite side is located in the third space 42c.

[0065] A cylindrical second passing pipe 54 is disposed inside the housing 41 so as to penetrate the partition 49 located between the second space 42b and the third space 42c. An opening on one side of the second passing pipe 54 is located in the third space 42c, and an opening on the opposite side is located in the second space 42b.

[0066] A guide pipe 46 having a configuration similar to that of the third embodiment is provided on the upper surface of the housing 41. A gas vent passage 47 and an unburned gas outlet 48 are formed in the guide pipe 46. The gas vent passage 47 is connected to the second space 42b.

[0067] In this embodiment, the exhaust gas flowing through the exhaust pipe 27 is first introduced into the first space 42a. The exhaust gas from the first space 42a passes through the first passage pipe 53 and flows into the third space 42c. The exhaust gas from the third space 42c reverses its flow direction and flows into the second space 42b through the second passage pipe 54. As the exhaust gas flows through each space, the energy of the exhaust gas is attenuated, and a sound absorbing effect can be obtained. Finally, the exhaust gas from the second space 42b passes through the gas vent passage 47 and is discharged to the outside of the housing 41.

[0068] In this manner, in this embodiment, similarly to the third embodiment, the unburned gas outlet 48 formed in the guide pipe 46 serves both as an outlet for combusted exhaust gas and an outlet for unburned hydrogen gas.

[0069] In this embodiment, similarly to the third embodiment, a gap 50 is formed in the upper part of each partition 49. Therefore, unburned hydrogen gas remaining in the internal space 42 of the housing 41 can be smoothly discharged from the unburned gas outlet 48.

[0070] Next, a fifth embodiment will be described with reference to FIG.

[0071] In the muffler 23d of this embodiment shown in Fig. 6, the guide pipe 46 is omitted. A gas vent hole 52 is formed in the rear part of the upper surface of the housing 41 in a penetrating manner. The gas vent hole 52 essentially functions as a short exhaust flow path. In this manner, the unburned gas outlet can also be the outlet of a through hole simply formed in the housing 41.

[0072] Next, a sixth embodiment will be described with reference to FIG.

[0073] 7, an on-off valve 55 is disposed midway through the gas vent passage 47. The on-off valve 55 is configured as, for example, a solenoid valve.

[0074] The on-off valve 55 is electrically connected to a control device 56. The control device 56 is a known computer equipped with a CPU, ROM, RAM, etc. The control device 56 may be realized by the same hardware as the ECU provided in the motorcycle 1, or may be realized by different hardware.

[0075] As an example, the control device 56 monitors the traveling speed of the motorcycle 1, and controls the on-off valve 55 to close when the body 2 is substantially stopped, and to open when the body 2 is traveling. Information on the traveling speed can be obtained based on the detection results of a wheel speed sensor 57 provided on either the front wheel 6 or the rear wheel 7. However, this is not limiting, and information on the traveling state of the body 2 can be obtained, for example, from an IMU sensor provided at an appropriate position on the body 2. IMU is an abbreviation for inertial measurement unit.

[0076] When the motorcycle 1 is traveling, the area around the vehicle body 2 is usually open, but when the vehicle is stopped, the vehicle body 2 may be in a closed, narrow space, such as indoors. In this case, the control device 56 controls the on-off valve 55 to close. This makes it possible to prevent unburned hydrogen gas from being released into a closed space.

[0077] The control of opening and closing of the on-off valve 55 is not limited to the above, and can be performed by detecting various conditions of the vehicle body 2 and the engine 22. For example, the control device 56 can be configured to switch the on-off valve 55 between opening and closing in response to the driver operating an operation switch provided on the steering wheel 8.

[0078] The on-off valve 55 can be disposed at any position in the vent passage 47. For example, the on-off valve 55 can be disposed at a connection portion between the internal space 42 of the housing 41 and the vent passage 47, at a midway portion of the vent passage 47, or at the unburned gas outlet 48.

[0079] The on-off valve 55 is not limited to an electrically operated on-off valve (for example, a solenoid valve), but may be configured as a manually operated on-off valve.

[0080] As described above, in the motorcycle 1 of this embodiment, the gas vent passage 47 connecting the unburned gas outlet 48 and the internal space 42 of the housing 41 can be opened and closed.

[0081] This makes it possible to prevent the unburned hydrogen gas discharged from the unburned gas outlet 48 from floating around the motorcycle 1 for long periods of time, for example, by allowing the discharge of unburned hydrogen gas from the unburned gas outlet 48 only when the motorcycle 1 is traveling.

[0082] The motorcycle 1 of this embodiment includes an on-off valve 55 and a control device 56. The on-off valve 55 opens and closes a flow path that connects the unburned gas outlet 48 and the internal space 42. The control device 56 controls the opening and closing of the on-off valve 55 in accordance with the traveling state of the vehicle body 2.

[0083] This makes it possible to control whether or not unburned hydrogen gas is discharged depending on the situation.

[0084] Although the preferred embodiment of the present disclosure has been described above, the above configuration can be modified, for example, as follows. A single modification may be made, or multiple modifications may be made in any combination.

[0085] Of the inner wall surfaces of the housing 41 that form the internal space 42, an opening may be provided on the upper part of the rear surface instead of the ceiling surface. In this case, the guide pipe 46 can be provided so as to protrude rearward from the upper part of the rear end surface of the housing 41, and the above opening and the unburned gas outlet 48 can be connected by a gas vent flow path 47.

[0086] In the first, second and fifth embodiments, the ceiling surface of the housing 41 may be arranged horizontally without being inclined.

[0087] The partition 49 shown in the third embodiment may be applied to the first embodiment. In this case, the outlet pipe 44 and the guide pipe 46 are provided so as to connect the space at the downstream end (rearmost part) of the multiple spaces divided by the partition 49 in the internal space 42 of the housing 41 to the outside. The partition 49 may be applied to the second or fifth embodiment.

[0088] In the third and fourth embodiments, the gas vent passage 47 may be connected to any one of the spaces divided by the partitions 49 .

[0089] The housing 41 may have a shape that bulges, for example, only upward with respect to the exhaust pipe 27 or the outlet pipe 44 .

[0090] The opening area of ​​the exhaust outlet 45 may be smaller than the opening area of ​​the unburned gas outlet 48. The two opening areas may be equal.

[0091] The guide portion 51 may be omitted.

[0092] Unburned gas outlet 48 may be connected to engine 22 to return light unburned gases to the intake side of engine 22 .

[0093] The inner wall surfaces of the housing 41, particularly the ceiling surface, may be made of a material having a function of suppressing hydrogen embrittlement, or may be coated with such a material.

[0094] The exhaust structure for unburned light gas described in each embodiment may be applied to an exhaust part having a large cross-sectional area of ​​an exhaust passage, and may be applied to an exhaust part other than a muffler, for example, a secondary silencer provided upstream of a muffler. For example, in the case of a motorcycle, the exhaust structure for unburned light gas may be applied to an exhaust chamber disposed in a space between a rear wheel and a body frame in the front-rear direction.

[0095] Some vehicles may be provided with multiple mufflers, such as a muffler and a secondary muffler. In this case, both mufflers may have an unburned gas outlet, or only one of the mufflers may have an unburned gas outlet. When only one of the mufflers has an unburned gas outlet, it is preferable to form the unburned gas outlet in the downstream muffler where the exhaust gas flow velocity is relatively slow. This can promote the discharge of unburned gas that accumulates due to the slow flow velocity.

[0096] The above-mentioned exhaust structure for the unburned light gas may be used in a sound deadening structure utilizing Helmholtz type resonance. In this case, an unburned gas outlet may be formed in the upper wall of the resonance chamber.

[0097] A catalyst that utilizes an oxidation-reduction reaction is sometimes used as an exhaust component to purify nitrogen oxides (NOx), which are formed by oxidizing nitrogen contained in the air due to the combustion of a fuel mixture. In order to improve purification performance, the catalyst may be formed with a passage cross-sectional area larger than the exhaust passage upstream of the catalyst. In this configuration, the unburned gas outlet described in each of the above embodiments may be formed in the space in which the catalyst is housed or in another space communicating with that space. This promotes the discharge of unburned gas in the catalyst space, and makes it possible to suppress unburned gas remaining in the catalyst space.

[0098] The above-mentioned unburned light gas emission structure can be applied not only to two-wheeled motor vehicles 1 (saddle-riding vehicles, lean vehicles), but also to a wide range of vehicles such as three-wheeled vehicles, four-wheeled vehicles, ships, aircraft, etc. Vehicles include moving bodies that move without a human on board.

[0099] The application of the unburned light gas exhaust structure of the present disclosure is not limited to a moving body. That is, the unburned light gas exhaust structure can be applied to exhaust parts of a fixed type lightweight fuel gas internal combustion engine. For example, the unburned light gas exhaust structure may be applied to exhaust parts provided in a power generation device or an internal combustion engine as a hydraulic drive device that does not have a moving propulsion source. [Explanation of symbols]

[0100] 1. Motorbike (vehicle) 2. Body 22 Engine (lightweight fuel gas internal combustion engine) 23 Muffler (exhaust parts) 27 Exhaust pipe 41 Housing 42 Interior Space 45 Exhaust outlet 47 Gas vent passage (exhaust passage) 48 Unburned gas outlet 49 Partition 50 Gap (circulation passage) 51 Information Department 55 On-off valve 56 Control device

Claims

1. a lightweight fuel gas internal combustion engine that outputs a driving force obtained by burning a lightweight gas fuel that is lighter than air; an exhaust component connected to an exhaust pipe of the light fuel gas internal combustion engine; A vehicle comprising: The exhaust component includes a housing that extends at least upwardly beyond the exhaust pipe, A vehicle, wherein the exhaust component is provided with an unburned gas outlet that connects an upper portion of the interior space of the housing with a higher exterior space.

2. 2. The vehicle of claim 1, The exhaust component includes an exhaust passage connected to the internal space, The exhaust flow path is inclined upward as it proceeds downstream in the exhaust direction, The unburned gas outlet is disposed at a downstream end of the exhaust flowpath.

3. 2. The vehicle of claim 1, In the housing, a ceiling surface of an inner wall surface that defines the internal space is inclined, The unburned gas outlet is connected to an upper portion of the ceiling surface.

4. 2. The vehicle of claim 1, the exhaust component includes an exhaust outlet for discharging exhaust gas introduced into the exhaust component; The exhaust outlet is formed at a different location from the unburned gas outlet.

5. 5. A vehicle as claimed in claim 4, The opening area of ​​the exhaust outlet is larger than the opening area of ​​the unburned gas outlet.

6. 2. The vehicle of claim 1, The unburned gas outlet or a flow path connecting the unburned gas outlet and the internal space is openable and closable.

7. 7. A vehicle as claimed in claim 6, an on-off valve that opens and closes the unburned gas outlet or a flow path that connects the unburned gas outlet and the internal space; a control device that controls the opening and closing of the on-off valve in response to at least one of the conditions of the lightweight fuel gas internal combustion engine and the vehicle body; A vehicle equipped with:

8. 2. The vehicle of claim 1, The internal space of the housing is divided into a plurality of spaces by partitions, The unburned gas outlet is connected to an upper portion of any one of the plurality of spaces, A vehicle, wherein a flow passageway connecting the partitioned spaces is formed in an upper portion of the partition located between adjacent spaces.

9. 9. A vehicle as claimed in claim 8, A guide portion is provided above the unburned gas outlet, for guiding the unburned gas that has flowed out from the unburned gas outlet into the external space.

10. 2. The vehicle of claim 1, The interior space of the housing is a sound-absorbing chamber that reduces exhaust noise from the light fuel gas internal combustion engine.

11. An exhaust part for use in a vehicle equipped with a lightweight fuel gas internal combustion engine that outputs a driving force obtained by burning a lightweight gas fuel that is lighter than air, the exhaust part being connected to an exhaust pipe of the lightweight fuel gas internal combustion engine, a housing that bulges at least upward from the exhaust pipe, An exhaust component having an unburned gas outlet formed therein that connects an upper portion of the interior space of the housing with an exterior space at a higher position.

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