Exhaust structure for leaked gaseous fuel in gaseous-fuel engine mounting unit

Abstract

Provided is an exhaust structure for exhausting leaked gaseous fuel. A gaseous-fuel engine mounting unit 1 is constructed by partitioning the inside of a soundproof box 10 into two compartments, namely an engine compartment 14 and an exhaust compartment 16, by means of a partition wall 12, and housing a gaseous-fuel engine 50, a fuel supply passage 60 for introducing gaseous fuel into the engine 50, and non-waterproof equipment in the engine compartment 14. A housing box 20 is disposed in the engine compartment 14, an internal space 21 through which cooling air generated by a cooling fan 51 for the gaseous-fuel engine 50 does not pass is formed in the housing box 20, the fuel supply passage 60 is housed in the internal space 21, any gaseous fuel that has leaked into the internal space 21 is arranged to be naturally exhausted or forcibly exhausted into the exhaust compartment 16 through an exhaust duct 30, and an exhaust guard 40 for preventing the cooling air from entering an outlet port 32 of the exhaust duct 30 is provided in front of the outlet port 32.

Description

Exhaust Structure for Leaked Gas Fuel of Gas Fuel Engine Mounted Unit

[0001] The present invention relates to an exhaust structure for exhausting leaked gas fuel in a unitized device (referred to as a "gas fuel engine mounted unit" in the present invention) that houses a gas fuel engine (referred to as a "gas fuel engine" in the present invention), which is an internal combustion engine using a combustible gas such as hydrogen gas as fuel, a fuel supply path that supplies fuel from a fuel source to the gas fuel engine, and other component devices in a soundproof box.

[0002] In the present invention, the "gas fuel engine" widely includes engines that can use gas fuel as fuel, such as gas fuel dedicated combustion engines that can only use gas fuel as fuel, and engines that can selectively or mix both gas fuel and liquid fuel for use as fuel.

[0003] As the society's interest in environmental issues has increased, the demand for decarbonization has been required in all fields, and the civil engineering and construction fields are no exception.

[0004] Therefore, as part of the response to such decarbonization, engines mounted on engine-driven work machines such as engine-driven generators and engine-driven compressors, which are frequently used at civil engineering and construction sites, etc., are also being considered to shift to gas fuel engines that use natural gas with a lower CO2 emission during combustion compared to petroleum fuel, or hydrogen gas that does not generate CO2 during combustion, etc. as fuel.

[0005] Here, as shown in Figure 6, in a soundproof box 110 in which the interior is divided into two rooms by a vertically erected partition wall 112, one of which is an engine room 114 housing a gaseous fuel engine 150, and the other is an exhaust room 116 for discharging cooling air that has cooled the engine room to the outside of the machine, in addition to the gaseous fuel engine 150, the engine room 114 also houses a fuel supply passage 160 for supplying fuel from a fuel source 170 to the gaseous fuel engine 150, a work machine (not shown) driven by the gaseous fuel engine 150, an intake air cleaner (not shown), a battery (not shown), and various other electrical components (not shown), etc., and the equipment is formed by integrating these into a unit, there is a risk of fuel leakage in the engine room 114 due to deterioration of the piping constituting the aforementioned fuel supply passage 160, or deterioration of the sealing material provided at the connection points between the piping and joints, various valves 163, 164, 166, and other equipment.

[0006] If leaked gaseous fuel accumulates inside the soundproof box 110, there is a risk of accidents such as ignition, so it is desirable to allow leaked gaseous fuel from the fuel supply passage 160 to be exhausted outside the aircraft.

[0007] Although this invention is not related to a gaseous fuel engine unit, Patent Documents 1 and 2, listed below, propose an exhaust structure for a fuel cell power generation device in which a fuel cell body and a fuel gas supply system (fuel supply piping, etc.) for the fuel cell body are housed inside a soundproof box. This exhaust structure involves providing an exhaust port in the soundproof box, and in the event of a leak of flammable fuel gas inside the soundproof box, the leaked fuel gas is discharged through the exhaust port.

[0008] Japanese Patent Publication No. 11-86891 Japanese Patent Publication No. 2016-143624

[0009] Here, following the exhaust structure of the fuel cell power generation device described in the aforementioned Patent Documents 1 and 2, and considering the need to allow natural exhaust in the event of leakage of gaseous fuels such as hydrogen gas, which is lighter than air, it is conceivable to provide an exhaust port 200 leading to the outside of the machine at the upper end of the engine chamber 114 of the gaseous fuel engine mounting unit 100, as shown in Figure 6.

[0010] However, if an exhaust structure is adopted in which an exhaust port 200 is provided at the upper end of the engine compartment 114, when the soundproof box 110 is installed outdoors, rainwater can easily enter the engine compartment 114 through the exhaust port 200 during rainy weather. This can cause problems as rainwater can come into contact with the engine 150, as well as other water-sensitive, non-water-resistant equipment housed in the engine compartment 114, such as the intake air cleaner and electrical components, leading to malfunctions.

[0011] Furthermore, in the central part of the partition wall 112 of the soundproof box 110 shown in Figure 6, a communication port 113 is provided that connects the engine room 114 and the exhaust room 116, and an air guide plate 119 is attached to guide the cooling air toward the communication port 113. In the exhaust room 116, an air-cooled heat exchanger 152, such as an engine radiator or an oil cooler provided on a work machine, is installed facing the communication port 113.

[0012] Because a large amount of cooling air is required to cool this air-cooled heat exchanger 152, the gaseous fuel engine 150 is equipped with a relatively large cooling fan 151.

[0013] Furthermore, while the gaseous fuel engine 150 is operating, the cooling fan 151 generates a strong flow of cooling air inside the soundproof box 110, from the air intake 117 provided on the side of the engine compartment 114, through the communication port 113, toward the exhaust port 118 provided on the upper surface of the exhaust chamber 116. As a result, this cooling air creates negative pressure at the exhaust port 200, which can cause rainwater to be drawn in through the exhaust port 200.

[0014] Therefore, in view of the above-mentioned problems, the present invention aims to provide an exhaust structure for leaked gaseous fuel in a gaseous fuel engine-equipped unit that can prevent rainwater from entering the engine compartment while discharging gaseous fuel leaked in the engine compartment to the exhaust chamber.

[0015] The means for solving the problem are described below, along with the reference numerals used in the embodiments for carrying out the invention. These reference numerals are included to clarify the correspondence between the claims and the descriptions of the embodiments for carrying out the invention, and needless to say, they are not used restrictively to interpret the technical scope of the present invention.

[0016] To achieve the above objective, the exhaust structure for leaked gaseous fuel of the gaseous fuel engine mounted unit 1 of the present invention divides the inside of the soundproof box 10 into two chambers by a partition wall 12. One chamber is an engine chamber 14 that houses a gaseous fuel engine 50 that uses a flammable gas as fuel and is equipped with a cooling fan 51, a fuel supply passage 60 that supplies gaseous fuel from a fuel source 70 to the gaseous fuel engine 50, and non-waterproof equipment (for example, intake air cleaner and electrical components). The other chamber is an exhaust chamber 16 that communicates with the engine chamber 14 via a communication opening 13 provided in the partition wall 12. In a gaseous fuel engine mounted unit 1, an exhaust port 18 communicating with the outside is provided at the upper end of the chamber 16, and an air-cooled heat exchanger 52 is arranged in the exhaust chamber 16 so as to face the communication port 13, and when the gaseous fuel engine 50 is operating, cooling air for the air-cooled heat exchanger 52 generated by the rotation of the cooling fan 51 is introduced from the engine chamber 14 to the exhaust chamber 16 via the communication port 13 and discharged from the exhaust port 18, A housing box 20 for the fuel supply passage 60 is placed inside the engine compartment 14, forming an internal space 21 inside the housing box 20 that does not allow the cooling air generated by the cooling fan 51 to pass through, housing the fuel supply passage 60 inside the internal space 21, and connecting the internal space 21 to the outside through an exhaust port 23 provided in the housing box 20, an exhaust duct 30 is provided that penetrates the partition wall 12 and is placed between the engine compartment 14 and the exhaust chamber 16, having an inlet 31 at one end that communicates with the exhaust port 23 and an outlet 32 ​​at the other end that opens vertically downward in the exhaust chamber 16, and the configuration is such that gaseous fuel leaked in the internal space 21 is naturally or forcibly exhausted into the exhaust chamber 16 via the exhaust duct 30, and an exhaust guard 40 is provided in front of the outlet 32 ​​of the exhaust duct 30 in the exhaust direction to prevent the cooling air from entering the outlet 32. The exhaust guard 40 is configured such that rainwater that enters the exhaust guard 40 can be drained downward through the drainage section 44 (Claim 1).

[0017] In order to configure the system so that the gaseous fuel leaked in the aforementioned internal space 21 is naturally exhausted into the exhaust chamber 16 via the exhaust duct 30, the present invention uses a gaseous fuel lighter than air (for example, hydrogen gas) as the gaseous fuel from the fuel source 70, and the exhaust port 23 is provided at the upper end of the housing box 20, and the outlet 32 ​​of the exhaust duct 30 may open above the upper end of the housing box 20 (Claim 2).

[0018] Furthermore, in order to forcibly exhaust the gaseous fuel that has leaked in the aforementioned internal space 21 into the exhaust chamber 16 via the exhaust duct 30, the present invention may also include a ventilation fan 24 in the storage box 20 that generates a ventilation flow toward the exhaust port 23 (Claim 3).

[0019] Furthermore, it is preferable that the exhaust guard 40 has a guard surface 42 that blocks the cooling air flowing toward the outlet 32 ​​of the exhaust duct 30 and guides it to flow toward the exhaust port 18 (Claim 4).

[0020] With the configuration of the present invention described above, the following remarkable effects can be obtained in the exhaust structure for leaked gaseous fuel of the gaseous fuel engine-mounted unit of the present invention.

[0021] In the exhaust structure for leaked gaseous fuel in the gaseous fuel engine-mounted unit of the present invention, the gaseous fuel leaking from the fuel supply passage 60 can be contained within the internal space 21 of the containment box 20 and naturally or forcibly exhausted to the exhaust chamber 16 via the exhaust duct 30. This eliminates the need to form the aforementioned exhaust port 200 at the upper end of the engine compartment 14, thereby preventing the engine, non-waterproof equipment, etc., housed in the engine compartment 14 from malfunctioning due to rainwater entering through the aforementioned exhaust port 200.

[0022] Furthermore, by opening the outlet 32 ​​of the exhaust duct 30 vertically downward within the exhaust chamber 16, it was possible to prevent rainwater from entering the exhaust duct 30 from the outlet 32.

[0023] Furthermore, by configuring the exhaust guard 40 to allow water that enters it to drain through drainage sections 44, which consist of holes or grooves formed in the exhaust guard 40, it was possible to prevent rainwater from entering the exhaust duct 30 from the exhaust guard 40 through the outlet 32.

[0024] As described above, the exhaust structure for leaked gaseous fuel in the gaseous fuel engine unit of the present invention prevents rainwater from entering the engine compartment 14.

[0025] Furthermore, because the exhaust guard 40 has the guard surface 42, the flow of the cooling air was not obstructed by the exhaust guard 40, and the flow to the exhaust port 18 was maintained smoothly.

[0026] An explanatory diagram showing an example configuration of the gaseous fuel engine mounted unit of the present invention. An enlarged view of the exhaust guard 40 portion of the gaseous fuel engine mounted unit of Figure 1. A diagram showing a modified example of the exhaust guard 40. An explanatory diagram showing another example configuration of the gaseous fuel engine mounted unit of the present invention. An explanatory diagram showing yet another example configuration of the gaseous fuel engine mounted unit of the present invention. An explanatory diagram of the basic structure of the gaseous fuel engine mounted unit.

[0027] The gaseous fuel engine mounting unit of the present invention will be described below with reference to the attached drawings.

[0028] In the following explanation, we will use the case where the gaseous fuel is hydrogen gas as an example. However, the application of the present invention is not limited to gaseous fuel engine units (hydrogen engine units) that use hydrogen gas as fuel, but is also applicable to gaseous fuel engine units that use other known gaseous fuels such as natural gas.

[0029] [Basic Structure of Gas Fuel Engine Mounted Unit] Figure 1 shows the overall configuration of the exhaust structure for leaked gaseous fuel in the gas fuel engine mounted unit of the present invention.

[0030] First, the basic structure of the gaseous fuel engine-mounted unit relating to the exhaust structure for leaked gaseous fuel of the gaseous fuel engine-mounted unit of the present invention will be described.

[0031] In Figure 1, reference numeral 1 denotes a gaseous fuel engine mounted unit (hydrogen engine mounted unit). This gaseous fuel engine mounted unit 1 comprises a gaseous fuel engine 50, which is an internal combustion engine that uses hydrogen gas as fuel, and a fuel supply passage 60 that supplies hydrogen gas from a fuel source (hydrogen source) 70 to the gaseous fuel engine 50, as well as a soundproof box 10 that houses these components.

[0032] In this embodiment, the gaseous fuel engine 50 is described as a hydrogen-only engine that operates using only hydrogen gas as fuel. However, the present invention may also be applied to a gaseous fuel engine unit 1 that is configured to include a liquid fuel supply passage (not shown) for supplying liquid fuel such as diesel or gasoline to the gaseous fuel engine 50, allowing for selective supply of hydrogen fuel and liquid fuel, or simultaneous supply of hydrogen fuel and liquid fuel.

[0033] The aforementioned fuel source 70 may be a hydrogen gas cylinder, or it may be a tank filled with liquefied hydrogen. In the latter case, a vaporizer for vaporizing liquefied hydrogen to obtain hydrogen gas may be included in the configuration of the fuel source 70 along with the liquefied hydrogen tank.

[0034] The fuel supply line 60 connected to the aforementioned fuel source 70 is for supplying hydrogen gas from the fuel source 70 to the gaseous fuel engine 50.

[0035] In the illustrated embodiment, the fuel supply line 60 includes a check valve 63, a fuel shut-off valve 64, a manual auxiliary fuel shut-off valve 65, and a pressure regulating valve 66 in the piping, and pressure sensors 67a and 67b are provided on the primary and secondary sides of the pressure regulating valve 66, respectively.

[0036] The aforementioned check valve 63 prevents gas in the fuel supply passage 60 from flowing back to the fuel source 70, and various known check valves can be used.

[0037] The fuel shut-off valve 64 controls the start and stop of hydrogen gas supply to the gaseous fuel engine 50 by opening and closing the fuel supply passage 60, and in the illustrated embodiment, it is configured as a solenoid valve.

[0038] The manual auxiliary fuel shut-off valve 65 is provided as an auxiliary to the aforementioned fuel shut-off valve (solenoid valve) 64. It is used when the fuel shut-off valve (solenoid valve) 64 fails to operate due to a malfunction or other reason, making it impossible to stop the fuel supply, or when it is necessary to emergency stop the fuel supply. The operator can manually operate the auxiliary fuel shut-off valve 65, and it can be configured using various known manual on-off valves.

[0039] The pressure regulating valve 66 is used to regulate the gaseous fuel from the fuel source 70 to the pressure required by the gaseous fuel engine 50, and can be configured using a known pressure regulator or the like.

[0040] In this embodiment, for example, high-pressure hydrogen gas (for example, up to 14.7 MPa) from a hydrogen gas cylinder, which is the fuel source 70, is reduced to the pressure required by the gaseous fuel engine 50 (1 MPa or less) and supplied to the gaseous fuel engine 50.

[0041] In the above explanation, the case in which the pressure adjustment of the gaseous fuel by the pressure regulating valve 66 is performed by "reducing pressure" was used as an example. However, if the pressure of the fuel required by the gaseous fuel engine 50 is higher than the pressure of the gaseous fuel supplied from the fuel source 70, the pressure regulating valve 66 may be used to "increase the pressure" of the gaseous fuel before introducing it into the gaseous fuel engine 50.

[0042] Furthermore, in the illustrated configuration, the aforementioned pressure regulating valve 66 is located in the fuel supply passage 60 closer to the gaseous fuel engine 50. However, the pressure regulating valve 66 may also be located in the fuel supply passage 60 closer to the fuel source 70, and is not limited to the illustrated arrangement.

[0043] Furthermore, if the fuel source 70 is equipped with a pressure regulating valve such as a pressure regulator, and hydrogen gas that has been adjusted to the required pressure on the gaseous fuel engine 50 side can be introduced into the fuel supply line 60, then it is not necessary to provide a pressure regulating valve 66 in the fuel supply line 60.

[0044] Incidentally, in the illustrated configuration, the pressure sensor 67a provided on the primary side of the pressure regulating valve 66 monitors whether the pressure of the gaseous fuel before pressure regulation by the pressure regulating valve 66 is a high pressure (for example, up to 14.7 MPa at maximum) from the hydrogen gas cylinder which is the fuel source 70, and the pressure sensor 67b provided on the secondary side monitors whether the pressure of the gaseous fuel after pressure regulation by the pressure regulating valve 66 is regulated to a predetermined pressure (1 MPa or less in this embodiment).

[0045] Also, in the illustrated embodiment, the configuration in which the check valve 63, the fuel cut-off valve 64, the manual auxiliary fuel cut-off valve 65, the pressure regulating valve 66, and the pressure sensors 67a and 67b are provided in the fuel supply passage 60 has been described. However, the devices provided in the fuel supply passage 60 are not limited to these, and some of these may be omitted, or more devices may be provided.

[0046] Incidentally, in the present invention, the fuel supply passage 60 may have a configuration including a purge passage (not shown) branched from the supply passage for purging the hydrogen gas in the supply passage in addition to the supply passage connecting the above-described fuel source 70 and the gaseous fuel engine 50.

[0047] A working machine such as a generator or a compressor (not shown) is connected to the gaseous fuel engine 50 that receives the supply of gaseous fuel from the fuel source 70 via the above-described fuel supply passage 60, and the gaseous fuel engine 50 is configured to be able to drive these working machines.

[0048] Further, as shown in FIG. 1, the soundproof box 10 that houses the gas fuel engine 50 and the fuel supply passage 60 described above is partitioned into two chambers by a partition wall 12 disposed in a direction orthogonal to the longitudinal direction of the soundproof box 10. In one of the partitioned spaces, in addition to the fuel supply passage 60 and the gas fuel engine 50 described above, a non-waterproof equipment such as a work machine body (not shown), an intake air cleaner (not shown), a battery (not shown), and various other electrical components (not shown) is housed, and an engine room 14 is formed. In the other space, an air-cooled heat exchanger (for example, a radiator of the engine or an oil cooler provided in the work machine) 52 and a muffler 54 that forms an exhaust system of the gas fuel engine 50 are housed, and an exhaust chamber 16 for discharging the cooling air that has cooled the engine room 14 to the outside of the machine is formed.

[0049] As described above, it is necessary to avoid the intrusion of rainwater into the engine room 14 that houses the gas fuel engine 50 and non-waterproof equipment such as electrical components. On the other hand, there is no problem even if rainwater intrudes into the exhaust chamber 16.

[0050] Further, as shown in FIG. 1, a communication port 13 that communicates the engine room 14 and the exhaust chamber 16 is provided in the central portion of the partition wall 12, and a wind guide plate 19 that guides the cooling air toward the communication port 13 is attached.

[0051] Further, the gas fuel engine 50 is provided with a cooling fan 51 for introducing cooling air to the air-cooled heat exchanger 52. The cooling fan 51 faces the communication port 13 in the engine room 14. During the operation of the gas fuel engine 50, the cooling fan 51 rotates to introduce cooling air to the air-cooled heat exchanger 52 disposed facing the communication port 13 in the exhaust chamber 16.

[0052] Further, an air guide port 17 for introducing cooling air into the engine room 14 from the outside of the machine is provided at one end of the engine room 14, and an exhaust port 18 for discharging the cooling air that has cooled the engine room 14 and the air-cooled heat exchanger 52 to the outside of the machine is provided at the upper end of the exhaust chamber 16.

[0053] While the gaseous fuel engine 50 is operating, the cooling fan 51 rotates, generating a flow of cooling air from the air intake 17 through the communication port 13 towards the exhaust port 18 (see Figure 1). That is, the cooling air introduced into the engine compartment 14 via the air intake 17 cools the inside of the engine compartment 14, then passes through the air-cooled heat exchanger 52 to the exhaust chamber 16, and is discharged outside the machine via the exhaust port 18.

[0054] [Housing Box] In the exhaust structure for leaked gaseous fuel of the gaseous fuel engine mounted unit of the present invention, a housing box 20 for housing the aforementioned fuel supply passage 60 is further arranged inside the engine compartment 14 of the soundproof box 10 of the gaseous fuel engine mounted unit 1, which has the basic structure described above.

[0055] Then, within this housing box 20, an internal space 21 is formed that does not allow the cooling air generated by the cooling fan 51 of the gaseous fuel engine 50 to pass through, and the aforementioned fuel supply passage 60 is housed within this internal space 21.

[0056] The material of the storage box 20 is not particularly limited as long as it can form a space inside that does not allow the cooling air generated by the cooling fan 51 to pass through. For example, it can be made of metal, resin, or various other materials, and a combination of these materials may also be used.

[0057] If the fuel supply line 60 is equipped with equipment that can be operated manually by an operator, such as a manual auxiliary fuel shut-off valve 65, the housing box 20 is provided with a door (not shown) so that the operator can access this equipment.

[0058] Furthermore, by applying a sealant to the door stopper, etc., the internal space 21 of the storage box 20 is prevented from being affected by the cooling air when the door is closed, and the operator can operate the manual auxiliary fuel shut-off valve 65 housed in the internal space 21 by opening the door.

[0059] A portion of the containment box 20 (for example, the door mentioned above) may be made of a transparent material such as glass or acrylic, so that the operator can visually check the equipment inside the containment box 20 (for example, the switching position of a manual valve).

[0060] While the fuel supply line 60 may be housed in the housing box 20, hydrogen gas leakage overwhelmingly occurs at the connections between the piping and fittings, valves, sensors, etc., rather than at the piping itself. Therefore, even if a portion of the piping is located outside the housing box 20, it is preferable that fittings, valves (63-66), pressure sensors (67a, 67b), and other equipment are housed inside the housing box 20.

[0061] Furthermore, parts of the fuel supply line 60 that are difficult to house within the storage box 20, such as the connection point to the gaseous fuel engine 50 or its vicinity, do not necessarily need to be housed within the storage box 20.

[0062] In the embodiment shown in Figure 1, the housing box 20 is formed to have a longitudinal shape with the fuel source 70 side and the gaseous fuel engine 50 side as its ends (20a, 20b), respectively. The internal space 21 of the housing box 20 is connected to the outside of the internal space 21 only by an intake port 22 provided at the lower end of one end 20a (fuel source 70 side in the illustrated example) and an exhaust port 23 provided at the upper end of the other end 20b (gaseous fuel engine 50 side in the illustrated example). The intake port 22 opens within the engine chamber 14 and communicates directly with the engine chamber 14, while the exhaust port 23 communicates with the exhaust chamber 16 in order to connect to the exhaust duct 30, which will be described later.

[0063] Furthermore, a ventilation fan 24 is provided at either the intake port 22 or the exhaust port 23 (in the illustrated embodiment, the intake port 22) to generate a ventilation flow within the internal space 21 from the intake port 22 to the exhaust port 23, thereby enabling ventilation inside the housing box 20 by the operation of the ventilation fan 24.

[0064] In this embodiment, when the intake port 22 is open inside the engine compartment 14, the cooling fan 51 rotates as the gaseous fuel engine 50 operates, creating negative pressure inside the engine compartment 14. This negative pressure causes the air inside the housing box 20 to try to flow back into the engine compartment 14 through the intake port 22. However, by operating the ventilation fan 24 mentioned above at least while the gaseous fuel engine 50 is operating, and creating a ventilation flow from the intake port 22 to the exhaust port 23 inside the housing box 20, the internal space 21 of the housing box 20 is not affected by the cooling fan 51 of the gaseous fuel engine 50.

[0065] On the other hand, on the exhaust port 23 side, as will be described later, the front of the other end (outlet 32, described later) of the exhaust duct 30, one end (inlet 31, described later) which is connected to the exhaust port 23, is covered with an exhaust guard 40. This prevents the cooling air generated by the cooling fan 51 from entering the exhaust duct 30 in the exhaust chamber 16 and flowing into the storage box 20 via the exhaust duct 30.

[0066] This configuration ensures that the internal space 21 of the housing box 20 is maintained as a space through which cooling air generated by the cooling fan 51 of the gaseous fuel engine 50 does not pass.

[0067] Furthermore, in this embodiment, the exhaust port 23 is provided at the upper end of the housing box 20. For example, when the engine is stopped and the gaseous fuel engine 50 and ventilation fan 24 are not operating, hydrogen gas leaked into the internal space 21 moves to the upper end of the housing box 20 because it is lighter than air, and is discharged (natural exhaust) to the exhaust duct 30 via the exhaust port 23.

[0068] Thus, in the configuration of the exhaust structure for leaked gaseous fuel in the gaseous fuel engine-equipped unit of this embodiment shown in Figure 1, if the gaseous fuel is a gas lighter than air, such as hydrogen gas, the ventilation fan 24 does not need to be operated at all times. It may be operated only when the gaseous fuel engine 50 is operating and cooling air is being generated by the cooling fan 51 to prevent the aforementioned backflow and to ventilate the inside of the housing box 20.

[0069] However, even when using a gas lighter than air, such as hydrogen gas, as the fuel in the configuration shown in Figure 1, it is possible to use the system with the ventilation fan 24 operating continuously.

[0070] Furthermore, in the exhaust structure for leaked gaseous fuel of the gaseous fuel engine-equipped unit of this embodiment shown in Figure 1, even if the gaseous fuel used is a gas heavier than air, such as propane, when the ventilation fan 24 is operating, a ventilation flow is generated in the containment box 20 toward the exhaust port 23, so that the gaseous fuel leaked into the containment box 20 can be discharged (forced exhaust) to the exhaust duct 30 via the exhaust port 23.

[0071] Furthermore, regarding the ventilation fan 24, if the ventilation fan 24 is installed at the intake port 22 as in the embodiment shown in Figure 1, the motor of the ventilation fan 24 comes into contact with the air introduced from outside the soundproof box 10 and hardly comes into contact with the hydrogen gas. Therefore, it is not necessary to use an explosion-proof motor for the ventilation fan 24, and costs can be reduced.

[0072] On the other hand, if a ventilation fan 24 is installed in the exhaust port 23 instead of this configuration, it is preferable to use an explosion-proof motor for the ventilation fan 24, as leaked hydrogen gas comes into contact with the motor portion (not shown) of the ventilation fan 24 when it is discharged into the exhaust duct through the exhaust port 23.

[0073] As described above, by forming an internal space 21 within the housing box 20 that the cooling air generated by the cooling fan 51 does not pass through, and housing the fuel supply passage 60 within this internal space 21, it is possible to retain the hydrogen gas leaking from the fuel supply passage 60 within the housing box 20, both when the unit is stopped and when it is in operation, without being affected by the cooling air generated inside the soundproof box 10 by the cooling fan 51, and to exhaust it naturally or forcibly into the exhaust duct 30.

[0074] In addition, although the internal space 21 of the storage box 20 described above was formed as a single chamber, instead of this configuration, for example, the internal space 21 of the storage box 20 may be divided into multiple chambers (not shown) along the longitudinal direction of the storage box, and a predetermined section of the fuel supply passage 60 may be accommodated in each of these multiple chambers.

[0075] In this case, for example, a partition wall (not shown) may be provided in the internal space 21 of the storage box 20, dividing the internal space 21 into multiple rooms with this partition wall as the boundary. Alternatively, although not shown in the diagram, a storage box 20 may be formed by connecting multiple boxes, thereby creating independent rooms within each box.

[0076] Although not shown in the diagram, for example, each chamber formed within the storage box 20 may be provided with an intake port 22 and an exhaust port 23, and a ventilation fan 24 may be provided for each chamber, thereby enabling independent ventilation for each chamber.

[0077] [Exhaust Duct] In the exhaust structure for leaked gaseous fuel of the gaseous fuel engine-mounted unit of the present invention, an exhaust duct 30 is provided to guide the fuel gas that has leaked in the internal space 21 of the containment box 20 from the containment box 20 to the exhaust chamber 16.

[0078] As shown in Figure 1, the exhaust duct 30 penetrates the partition wall 13 and is positioned between the engine compartment 14 and the exhaust chamber 16. It has an inlet 31 at one end that communicates with the exhaust port 23 of the housing box 20, and an outlet 32 ​​at the other end that opens vertically downward in the exhaust chamber 16.

[0079] Since rainwater can enter the exhaust chamber 16 through the exhaust port 18 located on its upper surface, the outlet 32 ​​is opened vertically downwards as described above to prevent rainwater from entering the exhaust duct 30 through the outlet 32. This prevents rainwater from entering the storage box 20 via the exhaust duct 30.

[0080] Furthermore, in the exhaust structure for leaked gaseous fuel of the gaseous fuel engine-equipped unit of this embodiment, which uses hydrogen gas, a gaseous fuel lighter than air, as described above, an exhaust port 23 is provided at the upper end of the containment box 20, and the leaked hydrogen gas is configured to be naturally exhausted from the internal space 21 of the containment box 20 through the exhaust port 23 to the exhaust duct 30. In addition, as shown in Figure 1, an outlet 32 ​​is opened at the upper end of the containment box 20, so that the hydrogen gas in the exhaust duct 30 is naturally exhausted to the exhaust chamber 16 through the outlet 32.

[0081] The hydrogen gas discharged into the exhaust chamber 16 is then discharged outside the machine through the exhaust port 18.

[0082] With the above configuration, even when the ventilation fan 24 is stopped, hydrogen gas leaked into the internal space 21 of the storage box 20 can be naturally exhausted to the exhaust chamber 16 via the exhaust duct 30.

[0083] On the other hand, even if the gaseous fuel used is a gas heavier than air, such as propane, in the exhaust structure for leaked gaseous fuel of the gaseous fuel engine-equipped unit of this embodiment, as described above, when the ventilation fan 24 is in operation, a ventilation flow is generated in the housing box 20 toward the exhaust port 23, and this ventilation flow further flows from the exhaust port 23 into the exhaust duct 30 and out from the outlet 32. As a result, this ventilation flow allows the gaseous fuel, which is heavier than air and has leaked into the internal space 21 of the housing box 20, to be discharged (forced exhaust) to the exhaust chamber 16 via the exhaust duct 30.

[0084] Furthermore, when using a gas heavier than air as the gaseous fuel, an exhaust fan (not shown) may be provided at the exhaust port 18 so that the cooling air can be discharged outside the machine through the exhaust port 18 even when the cooling fan 51 is not generating cooling air. This exhaust fan may be used to generate an exhaust flow that flows from the exhaust chamber 16 through the exhaust port 18 to the outside of the machine.

[0085] The exhaust duct 30 is not particularly limited and can be a rectangular duct, a cylindrical duct, or the like. Furthermore, the exhaust duct 30 can be made of resin, metal, or various other materials, and a combination of these materials may also be used.

[0086] Furthermore, as mentioned above, when the internal space 21 is divided into multiple rooms, it is preferable to use an exhaust duct 30 formed in a manifold shape, which has multiple inlets 31 that branch off from a single outlet 32 ​​and connect to exhaust ports 23 provided for each room, although this is not shown in the diagram.

[0087] [Exhaust Guard] The exhaust structure for leaked gaseous fuel in the gaseous fuel engine-mounted unit of the present invention includes an exhaust guard 40 located in front of the outlet 32 ​​of the exhaust duct 30 to prevent the cooling air generated by the cooling fan 51 from entering the outlet 32 ​​(see Figure 1).

[0088] As shown in Figure 2, the exhaust guard 40 of this embodiment has a flat plate-like structure comprising an inclined portion 40a that slopes downward toward the partition wall 12, a first vertical portion 40b that extends the upper end of the inclined portion 40a vertically upward to a position higher than the outlet 32, and a second vertical portion 40c that extends the lower end of the inclined portion 40a vertically downward.

[0089] Furthermore, the exhaust guard 40 shown in the figure is positioned such that the inclined portion 40a covers the front of the outlet 32 ​​(located on the extension of the opening direction of the outlet 32), and the second vertical portion 40c is positioned with a small gap between it and the partition wall 12 without contacting it.

[0090] The method of attaching the exhaust guard 40 is not particularly limited. For example, in the exhaust guard 40 shown in Figures 1 and 2, it may be detachably fixed by a bracket (not shown) attached to the inner wall or partition wall 12 of the bonnet that constitutes the exhaust chamber 16.

[0091] While the gaseous fuel engine 50 is in operation, the cooling fan 51 generates a strong flow of cooling air from the air intake 17 through the communication port 13 toward the exhaust port 18. There is a risk that this cooling air may flow into the housing box 20 through the outlet 32 ​​of the exhaust duct 30. In this embodiment, as shown in Figure 2, the exhaust guard 40 has an inclined portion 40a and a first vertical portion 40b that form a guard surface 42 that blocks the cooling air flowing toward the outlet 32 ​​and guides it toward the exhaust port 18. This guard surface 42 prevents the cooling air from flowing into the housing box 20 through the outlet 32, and also maintains a smooth flow toward the exhaust port 18 without causing stagnation of the cooling air flow.

[0092] Furthermore, since rainwater enters through the exhaust port 18 provided on the upper surface of the exhaust chamber 16, there is a risk that rainwater will accumulate on the exhaust guard 40, causing it to enter the exhaust duct 30 from the opposing outlet 32 ​​and flow into the storage box 20. However, as shown in Figure 2, the exhaust guard 40 of this embodiment has an inclined portion 40a and a second vertical portion 40c, and a small gap is provided between the second vertical portion 40c and the partition wall 12, and a drainage portion 44 is provided in this gap, so that water that enters on the exhaust guard 40 can be drained downward without accumulating.

[0093] Furthermore, the exhaust air guard 40 of the present invention is configured to be located in front of the outlet 32 ​​of the exhaust duct 30, preventing the cooling air from entering the outlet 32, and to allow water that enters the exhaust air guard 40 to be drained downward without accumulating. However, its dimensions, shape, and placement are not limited.

[0094] For example, if the inclined portion 40a of the exhaust guard 40 shown in Figures 1 and 2 is designed to be only slightly larger than the area of ​​the outlet 32, and there is a risk that cooling air may flow around to the outlet 32 ​​from both ends in the direction perpendicular to the inclination direction of the inclined portion 40a, then vertical portions (not shown) may be provided extending vertically upward from both ends in the direction perpendicular to the inclination direction of the inclined portion 40a to a position higher than the outlet, and the three vertical portions, including the first vertical portion 40b, may be designed to surround three sides of the inclined portion 40a. In this configuration, the inclined portion 40a and the three vertical portions surrounding the inclined portion 40a form a guard surface 42 that blocks the cooling air flowing toward the outlet 32 ​​and guides it toward the exhaust port.

[0095] On the other hand, if the inclined portion 40a of the exhaust guard 40 shown in Figures 1 and 2 is designed to be sufficiently larger than the area of ​​the outlet 32, for example, so that both ends in the direction perpendicular to the inclination direction are in contact with the inner wall of the exhaust chamber 16, and there is no risk of cooling air circulating from both ends in the direction perpendicular to the inclination direction, then it is not necessary to provide vertical portions that extend vertically upward from both ends of the inclined portion 40a in the direction perpendicular to the inclination direction.

[0096] In addition to the above, to prevent cooling air from flowing back from the inclined section 40a to the outlet 32, the distance between the exhaust guard and the outlet may also be adjusted.

[0097] In addition, as a modification of the exhaust guard 40 of the present invention, as shown in Figure 3, it may have a structure that includes vertical sections extending vertically upward from three sides of a rectangular horizontal section 40d in plan view to a position higher than the outlet 32 ​​(of the three vertical sections, only the vertical section 40e facing the partition wall 12 is shown, and the other two vertical sections are not shown).

[0098] As shown in Figure 3, this exhaust guard 40 is installed so as to be in contact with the partition wall 12.

[0099] The exhaust guard 40 shown in Figure 3 consists of a horizontal section 40d and the three vertical sections (40e) surrounding the horizontal section 40d on three sides, forming a guard surface 42 that blocks the cooling air flowing toward the outlet 32 ​​and guides it toward the exhaust port.

[0100] Furthermore, by providing drainage sections 44 consisting of small drainage holes at appropriate locations (preferably at both ends) on one side of the horizontal section 40d that connects to the vertical section 40e facing the partition wall 12, the system is configured to allow water that enters the exhaust guard 40 to be drained downward without accumulating.

[0101] [Modification 1] In the exhaust structure for leaked gaseous fuel of a gaseous fuel engine-equipped unit described with reference to Figure 1, a configuration was described in which the intake port 22 of the containment box 20 is opened inside the engine room 14, i.e., the soundproof box 10.

[0102] In contrast, the exhaust structure for leaked gaseous fuel in the gaseous fuel engine-equipped unit shown in Figure 4 employs a configuration in which the intake port 22 of the containment box 20 is opened outside the soundproof box 10, while the other configurations are the same as those of the exhaust structure for leaked gaseous fuel in the gaseous fuel engine-equipped unit described with reference to Figure 1.

[0103] As a result, even when the cooling fan 51 rotates in conjunction with the operation of the gaseous fuel engine 50, creating negative pressure inside the engine compartment 14, there is no risk of air from inside the storage box 20 flowing back into the engine compartment 14 through the intake port 22 due to this negative pressure.

[0104] Therefore, in order to prevent this backflow, it is no longer necessary to operate the ventilation fan 24 while the gaseous fuel engine 50 is running to generate a ventilation flow from the intake port 22 to the exhaust port 23 inside the housing box 20.

[0105] [Modification 2] The exhaust structure for leaked gaseous fuel in a gaseous fuel engine unit, as described above with reference to Figure 1, describes a configuration in which a gas detector is not installed.

[0106] In contrast, the exhaust structure for leaked gaseous fuel in the gaseous fuel engine-equipped unit shown in Figure 5 employs a configuration in which a gas detector is installed inside the containment box 20, while the other configurations are the same as those of the gaseous fuel engine-equipped unit 1 described with reference to Figure 1.

[0107] The exhaust structure for leaked gaseous fuel in the gaseous fuel engine-mounted unit of the present invention may be configured such that a gas detector 25 for detecting hydrogen gas, which is a gaseous fuel, is installed in the internal space 21 of the containment box 20, as shown in Figure 5.

[0108] In this way, by installing the gas detector 25 in the internal space 21 of the containment box 20, which is not through which the cooling air generated by the cooling fan 51 of the gaseous fuel engine 50 passes, and detecting hydrogen gas leaking inside the containment box 20, it becomes possible to detect hydrogen gas leaking from the fuel supply passage 60 without being affected by the cooling air generated inside the soundproof box 10 by the cooling fan 51 of the gaseous fuel engine 50.

[0109] In the illustrated example, the gas detector 25 itself is placed in the exhaust port 23, but it is sufficient that at least the sensing part of the gas detector 25 is placed near the exhaust port 23. For example, the sensing part of the gas detector 25 may be placed inside the exhaust duct 30, or it may be provided on the top or side wall of the housing box 20 near the inlet 31 of the exhaust duct 30.

[0110] By positioning the sensing element of the gas detector 25 near the exhaust port 23 located at the upper end of the containment box 20, when using a gaseous fuel lighter than air, such as hydrogen gas, leaked hydrogen gas can move towards the upper end of the containment box 20 even when the system is stopped and the ventilation fan 24 is not operating along with the gaseous fuel engine 50, and can therefore be detected by the aforementioned gas detector 25.

[0111] Furthermore, by positioning the sensing element of the gas detector 25 near the exhaust port 23, even if the gaseous fuel is a gas heavier than air, such as propane, when the ventilation fan 24 is operating, the gaseous fuel leaked into the storage box 20 will always pass through the exhaust port 23, allowing the gas detector 25 to reliably detect the leakage of gaseous fuel.

[0112] Furthermore, the exhaust structure for leaked gaseous fuel in the gaseous fuel engine unit shown in Figure 5 may also include an additional gas detector (not shown) located inside the engine compartment 14 outside the containment box 20.

[0113] As shown in Figure 5, the main portion of the fuel supply passage 60 is housed in the containment box 20. However, there are parts of the fuel supply passage 60, such as the end connected to the gaseous fuel engine 50, that are difficult to house in the containment box 20. On the other hand, hydrogen gas can leak from the portion of the fuel supply passage 60 that is located outside the containment box 20.

[0114] Therefore, an additional gas detector may be installed near the ceiling of the engine compartment 14 to detect hydrogen gas that has leaked into the engine compartment 14.

[0115] In this embodiment, where the gaseous fuel is hydrogen gas, which is lighter than air, the gas detector is preferably placed near the ceiling of the engine compartment 14, and more preferably near the ceiling above the portion of the fuel supply passage 60 that could not be accommodated in the storage box 20.

[0116] Thus, the gas detector installed in the engine compartment 14 outside the containment box 20 has difficulty detecting hydrogen gas leakage while the gaseous fuel engine 50 is operating, and therefore while cooling air is being generated by the cooling fan 51. However, it can detect leaked hydrogen gas when the cooling fan 51 stops and no cooling air is being generated inside the soundproof box 10.

[0117] In addition to the above, if the internal space 21 of the containment box 20 is divided into multiple chambers as described above, a gas detector may be installed in each chamber.

[0118] [Other Modifications] In the embodiments described above, the case in which hydrogen gas is used as a gaseous fuel has been described. However, the configuration of the present invention can be widely adopted not only as a configuration of a gaseous fuel engine equipped unit that uses hydrogen gas as fuel, but also as a configuration of a gaseous fuel engine equipped unit that has an engine driven by other gaseous fuels such as natural gas.

[0119] Furthermore, this configuration may be adopted as part of a gaseous fuel engine unit 1 equipped with a gaseous fuel engine that uses not only gaseous fuels lighter than air, such as hydrogen gas, but also gaseous fuels heavier than air, such as propane.

[0120] Thus, when using a gaseous fuel heavier than air, it is preferable to operate the ventilation fan 24 installed in the storage box 20 at all times. Furthermore, as mentioned above, it is preferable to install an exhaust fan (not shown) at the exhaust port 18 so that the cooling air can be discharged outside the machine through the exhaust port 18 even when the cooling fan 51 is not generating cooling air, and to operate the exhaust fan at least when the gaseous fuel engine 50 is stopped.

[0121] 1,100 Gas fuel engine mounted unit (hydrogen engine mounted unit) 10,110 Soundproof box 12,112 Partition wall 13,113 Communication port 14,114 Engine room 16,116 Exhaust chamber 17,117 Air guide port 18,118 Exhaust port 19,119 Air guide plate 20 Housing box 20a One end (of housing box) 20b Other end (of housing box) 21 Internal space 22 Intake port 23 Exhaust port 24 Ventilation fan 25 Gas detector 30 Exhaust duct 31 Inlet port 32 Outlet port 40 Exhaust guard 40a Inclined section 40b First vertical section 40c Second vertical section 40d Horizontal section 40e Vertical section 42 Guard surface 44 Drainage section (groove or hole) 50,150 Gas fuel engine 51,151 Cooling fan 52,152 Air-cooled heat exchanger 54 Muffler 60,160 Fuel supply line 63,163 Check valve 64,164 Fuel shut-off valve 65 Manual auxiliary fuel shut-off valve 66,166 Pressure regulating valve 67a,67b Pressure sensor 70,170 Fuel source 200 Exhaust port

Claims

1. In a gas fuel engine mounting unit, the inside of a soundproof box is divided into two rooms by a partition wall, one room is an engine room housing a gas fuel engine that uses a flammable gas as fuel and is equipped with a cooling fan, a fuel supply passage that supplies gas fuel from a fuel source to the gas fuel engine, and non-waterproof equipment, and the other room is an exhaust room that communicates with the engine room through a communication opening provided in the partition wall, an exhaust port that communicates with the outside of the machine is provided at the upper end of the exhaust room, and an air-cooled heat exchanger is arranged inside the exhaust room so as to face the communication opening, and cooling air for the air-cooled heat exchanger generated by the rotation of the cooling fan when the gas fuel engine is operating is introduced from the engine room into the exhaust room through the communication opening and discharged from the exhaust port, A gaseous fuel engine mounting unit is characterized by the following: a housing box for the fuel supply passage is placed in the engine compartment, forming an internal space in the housing box that does not allow the cooling air generated by the cooling fan to pass through; the fuel supply passage is housed in the internal space, and the internal space is connected to the outside of the internal space through an exhaust port provided in the housing box; an exhaust duct is provided that penetrates the partition wall and is placed between the engine compartment and the exhaust chamber, having an inlet at one end that communicates with the exhaust port and an outlet at the other end that opens vertically downward in the exhaust chamber; the gaseous fuel leaked in the internal space is configured to be naturally or forcibly exhausted into the exhaust chamber via the exhaust duct; an exhaust guard is provided in front of the outlet of the exhaust duct in the direction of exhaust to prevent the cooling air from entering the outlet; and the exhaust guard is configured so that rainwater that enters the exhaust guard can be drained downward through a drainage section.

2. The exhaust structure for leaked gaseous fuel of a gaseous fuel engine mounted unit according to claim 1, characterized in that a gaseous fuel lighter than air is used as the gaseous fuel from the fuel source, the exhaust port is provided at the upper end of the housing box, and the outlet of the exhaust duct opens above the upper end of the housing box.

3. The exhaust structure for leaked gaseous fuel of a gaseous fuel engine-mounted unit according to claim 1, characterized in that a ventilation fan is provided inside the housing box to generate a ventilation flow toward the exhaust port.

4. The exhaust structure for leaked gaseous fuel in a gaseous fuel engine-mounted unit according to any one of claims 1 to 3, characterized in that the exhaust guard has a guard surface that blocks the cooling air flowing toward the outlet of the exhaust duct and guides it to flow toward the exhaust port.

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