Device and method for discharging residual gas fuel in engine drive-type compressor with gas fuel engine unit

Abstract

To automatically discharge gas fuel remained in a fuel supply passage, and automatically create nitrogen gas for discharging the gas fuel, in an engine drive-type compressor with a gas fuel engine unit.SOLUTION: The device comprises a nitrogen gas supply flow path 30 communicated with an air tank 3 for storing compressed gas emitted from a compressor body 2, and capable of introducing nitrogen gas purified from the compressed air from the air tank 3 by a nitrogen gas purification device 32 provided at a middle of a flow path to the fuel supply path 22. After a gas fuel supply control mechanism 40 is operated by a control device 70 to execute gas fuel supply stop processing for blocking communication between a gas fuel source 20 and the fuel supply path 22, processing for controlling discharge of fuel in a supply path to introduce the nitrogen gas from the nitrogen gas supply flow path 30 to the fuel supply path 22 is executed by a nitrogen gas introduction control mechanism 60, while atmosphere is emitted in the fuel supply path 22 by an air emission mechanism 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a residual gaseous fuel discharge device and discharge method for an engine-driven compressor equipped with an engine, which is an internal combustion engine that operates by burning gaseous fuel such as hydrogen, and an engine unit (referred to as a "gaseous fuel engine unit" in the present invention) that is equipped with a fuel supply passage that supplies gaseous fuel to the engine, which automatically discharges the gaseous fuel so that no gaseous fuel remains in the fuel supply passage when the compressor is stopped.

[0002] In this invention, the term "gaseous fuel engine unit" broadly includes those equipped with a fuel supply line for supplying gaseous fuel such as hydrogen gas to an engine, and includes both engine units equipped with a gaseous fuel-only engine that can use only gaseous fuel as fuel, as well as engine units equipped with an engine that can use both gaseous fuel and liquid fuel selectively, or a mixture of gaseous fuel and liquid fuel as fuel. [Background technology]

[0003] In engine-driven compressors, diesel engines or gasoline engines are generally used as the engines that drive the compressor body.

[0004] However, as society becomes more concerned about environmental issues, the demand for decarbonization is growing in all sectors, and attention is now being paid to the use of gaseous fuels such as natural gas, which emits less CO2 when burned than petroleum fuels, and hydrogen gas, which does not produce CO2 when burned, in internal combustion engines (see Patent Document 1 below).

[0005] A gaseous fuel engine unit equipped with an engine that operates by burning such gaseous fuel is provided with a fuel supply passage for supplying high-pressure gaseous fuel to the engine from a gaseous fuel source such as a gaseous fuel-filled cylinder.However, if high-pressure gaseous fuel remains in the fuel supply passage even after the engine is stopped, the gaseous fuel remaining in the fuel supply passage will pass through the stopped engine and gradually leak into the engine compartment, creating a risk of the leaked gaseous fuel igniting.

[0006] Furthermore, if the gaseous fuel is hydrogen gas, if hydrogen gas remains in the fuel supply line, small hydrogen atoms can penetrate into metal materials such as piping in the fuel supply line, causing the material to become embrittled, a phenomenon known as "hydrogen embrittlement." This hydrogen embrittlement can lead to breakdowns in the gaseous fuel engine unit and subsequent accidents.

[0007] Therefore, when the engine is stopped, it is desirable to discharge the gaseous fuel remaining in the fuel supply passage to the gaseous fuel supply system or outside the engine, preferably to the engine room or outside the hood that houses the engine.

[0008] Regarding the automatic discharge of residual gaseous fuel in such a gaseous fuel engine unit, a gaseous fuel engine unit 100 equipped with a residual gaseous fuel discharge device 102 as shown in Figure 8, which has been filed as Patent Application No. 2024-008052 by the same applicant, can be considered.

[0009] In Figure 8, the symbol 100 denotes a gaseous fuel engine unit (hydrogen engine unit) that uses hydrogen gas as gaseous fuel, and this gaseous fuel engine unit 100 is equipped with an engine 110 as an internal combustion engine that operates by burning hydrogen gas, and a fuel supply path (hydrogen gas supply path) 122 that supplies hydrogen gas from a hydrogen cylinder (gaseous fuel source) 120 to the engine 110.

[0010] The hydrogen cylinder 120 is connected to a fuel supply path 122 via a check valve cv1' and a gas fuel supply valve 141 of a gas fuel supply control mechanism 140 described later, and the opening and closing of the gas fuel supply valve 141 controls the connection and blocking between the hydrogen cylinder 120 and the fuel supply path 122, while the check valve cv1' prevents gas in the fuel supply path 122 from flowing into the hydrogen cylinder 120.

[0011] 8, a gaseous fuel pressure regulator 124 that adjusts the pressure of hydrogen gas to a predetermined pressure is provided at an intermediate position of the aforementioned fuel supply path 122. The fuel supply path 122 on the primary side of the gaseous fuel pressure regulator 124 is referred to as a primary-side fuel supply path 122a, and the fuel supply path 122 on the secondary side of the gaseous fuel pressure regulator 124 is referred to as a secondary-side fuel supply path 122b.

[0012] The engine 110, which receives gaseous fuel via a fuel supply line 122, is provided with an engine control unit (ECU) 111 that controls the operation of the engine 110 and a starter motor 112 for starting the engine 110, and is configured so that the engine 110 can be started, stopped, and its speed controlled by a control device 170 consisting of an electronic control device such as a microcontroller provided in the gaseous fuel engine unit 100.

[0013] The gas fuel engine unit 100 configured as described above is provided with a residual gas fuel discharge device 102 that discharges hydrogen gas remaining in the fuel supply path 122 to the outside of the machine when the hydrogen supply from the hydrogen cylinder 120 is stopped, and replaces the hydrogen gas in the fuel supply path 122 with nitrogen gas.

[0014] The residual gaseous fuel discharge device 102 is composed of a nitrogen gas supply unit 130, a gaseous fuel supply control mechanism 140, an air release mechanism 150, a nitrogen gas introduction control mechanism 160, and a control device 170 that controls the operation of each mechanism.

[0015] The nitrogen gas supply unit 130 has a gas fuel supply valve 141 consisting of an air-operated on-off valve (air-operated valve) described later, a nitrogen cylinder 131 that stores nitrogen gas to be supplied as operating pressure to the air release valves 151 (primary side air release valve 151a, secondary side air release valve 151b) of the air release mechanism 150 (primary side air release mechanism 150a, secondary side air release mechanism 150b) described later, and to be introduced into the fuel supply path 122 (122a, 122b), and a nitrogen gas supply path 132 that is connected to the nitrogen cylinder 131. In addition, in the illustrated example, the nitrogen gas supply path 132 is provided with a nitrogen gas pressure regulator 133 that adjusts the nitrogen gas from the nitrogen cylinder 131 to a predetermined pressure, and on the secondary side of the nitrogen gas pressure regulator 133, it branches into four branches and is connected to a gas fuel supply control solenoid valve 143, a release valve control solenoid valve 153 (primary side release valve control solenoid valve 153a, secondary side release valve control solenoid valve 153b) and a nitrogen gas introduction control solenoid valve 161, which will be described later.

[0016] Next, the gaseous fuel supply control mechanism 140 controls the start and stop of supply of hydrogen gas to the fuel supply path 122 by connecting or blocking communication between the gaseous fuel source 120 and the fuel supply path 122 .

[0017] As shown in Figure 8, the gas fuel supply control mechanism 140 is composed of a gas fuel supply valve 141, which is an air-operated on-off valve (air valve) provided on the primary side 122a of the fuel supply path 122, a gas fuel supply valve control circuit 142 that introduces nitrogen gas as an operating pressure to the gas fuel supply valve 141, and a gas fuel supply control solenoid valve 143 that is composed of a solenoid valve (three-way solenoid valve) that connects the gas fuel supply valve control circuit 142 to the nitrogen gas supply path 132 or opens it to the atmosphere.

[0018] By providing the gaseous fuel supply control mechanism 140 having the above-described configuration, when the gaseous fuel supply control solenoid valve 143 is operated to connect the nitrogen gas supply path 132 to the gaseous fuel supply valve control circuit 142, nitrogen gas is introduced into the gaseous fuel supply valve 141, which opens the gaseous fuel supply valve 141 and introduces hydrogen gas, which is the gaseous fuel, into the fuel supply path 122.

[0019] On the other hand, when the gas fuel supply control solenoid valve 143 is operated to cut off communication between the nitrogen gas supply path 132 and the gas fuel supply valve control circuit 142 and open the gas fuel supply valve control circuit 142 to the atmosphere, the introduction of nitrogen gas into the gas fuel supply valve 141 is stopped, and the gas fuel supply valve 141 is closed by the force of the return spring, thereby stopping the introduction of hydrogen gas into the fuel supply path 122.

[0020] Next, the air release mechanism 150 controls the start and stop of opening the fuel supply passage 122 (122a, 122b) to the atmosphere.

[0021] In the gaseous fuel engine unit 100 shown in Figure 8, air discharge flow paths 154 (154a, 154b) are provided on the primary and secondary sides of the pressure regulator 124, branching off from the primary side fuel supply path 122a and the secondary side fuel supply path 122b, respectively, and the air discharge flow paths 154 (154a, 154b) are extended outside the aircraft.

[0022] The air release flow paths 154 (154a, 154b) are controlled to open and close by the air release mechanisms 150 (150a, 150b), respectively, so that opening of the fuel supply paths 122 (122a, 122b) to the atmosphere can be started or stopped.

[0023] The opening and closing of the air release flow path 154 (154a, 154b) through which hydrogen, a flammable gas, can flow is performed by an air release valve 151 (151a, 151b) consisting of an air-operated valve, and the aforementioned air release mechanism 150 (150a, 150b) is constituted by an air release valve control circuit 152 (primary side air release valve control circuit 152a, secondary side air release valve control circuit 152b) that introduces nitrogen gas as operating pressure to the air release valve 151 (151a, 151b), and an air release valve control solenoid valve 153 (153a, 153b) consisting of a three-way solenoid valve that connects this air release valve control circuit 152 (152a, 152b) to the nitrogen gas supply path 132 or opens it to the atmosphere.

[0024] With the above-described configuration, when the air release valve control solenoid valve 153 (153a, 153b) connects the air release valve control circuit 152 (152a, 152b) to the nitrogen gas supply path 132, nitrogen gas is introduced into the air release valve 151 (151a, 151b), and the air release valve 151 (151a, 151b) opens, thereby starting to open the fuel supply path 122 (122a, 122b) to the atmosphere.

[0025] On the other hand, when the air release valve control solenoid valve 153 (153a, 153b) cuts off the communication between the air release valve control circuit 152 (152a, 152b) and the nitrogen gas supply path 132 and opens the air release valve control circuit 152 (152a, 152b) to the atmosphere, the introduction of nitrogen gas stops, and the air release valve 151 (151a, 151b) closes due to the force of the return spring, and the opening of the fuel supply path 122 (122a, 122b) to the atmosphere is stopped.

[0026] Next, the nitrogen gas introduction control mechanism 160 controls the start and stop of introduction of nitrogen gas from the nitrogen cylinder 131 into the fuel supply path 122 (122a, 122b).

[0027] The nitrogen gas introduction control mechanism 160 in Figure 8 is composed of a nitrogen gas introduction flow path 162 that is connected to the nitrogen gas supply path 132 and introduces nitrogen gas from the nitrogen cylinder 131 into the fuel supply path 122, and a nitrogen gas introduction control solenoid valve (two-way solenoid valve) 161 that connects or disconnects this nitrogen gas introduction flow path 162 and the nitrogen gas supply path 132.

[0028] The nitrogen gas introduction flow path 162 branches into two on the secondary side, one of which is connected to the primary fuel supply path 122a via a check valve cv2', and the other of which is connected to the secondary fuel supply path 122b via a check valve cv3'. By connecting the nitrogen gas introduction flow path 162 to the fuel supply paths 122 (122a, 122b) via the check valves cv2' and cv3' in this way, hydrogen gas in the fuel supply paths is prevented from flowing into the nitrogen gas introduction flow path 162.

[0029] The control device 170 is composed of an electronic control device such as a microcontroller, and in addition to controlling the operation of the engine 110 described above, by executing a pre-stored program, it electrically controls the operation of each solenoid valve (gas fuel supply control solenoid valve 143, air release valve control solenoid valve 153 (153a, 153b), and nitrogen gas introduction control solenoid valve 161) provided in the gas fuel supply control mechanism 140, air release mechanism 150, and nitrogen gas introduction control mechanism 160 described above.

[0030] The operation of discharging residual gaseous fuel by the gaseous fuel engine unit 100 equipped with the residual gaseous fuel discharge device 102 configured as described above will be described.

[0031] When stopping the engine 110, in order to stop the supply of hydrogen gas to the engine 110, the control device 170 controls the gas fuel supply control solenoid valve 143 of the gas fuel supply control mechanism 140 to block communication between the nitrogen gas supply path 132 and the gas fuel supply valve control circuit 142 and open the gas fuel supply valve control circuit 142 to the atmosphere.

[0032] This stops the introduction of nitrogen gas into the gaseous fuel supply valve 141, and the gaseous fuel supply valve 141 closes due to the force of the return spring, stopping the supply of hydrogen gas from the hydrogen cylinder 120 to the fuel supply path 122 (122a, 122b).

[0033] Furthermore, after the supply of hydrogen gas is stopped as described above, the control device 170 controls the air release valve control solenoid valve 153 (153a, 153b) provided in the air release mechanism 150 (150a, 150b) to connect the air release valve control circuit 152 (152a, 152b) to the nitrogen gas supply path 132, thereby introducing nitrogen gas into the air release valve 151 (151a, 151b) to open the air release valve 151 (151a, 151b) and opening the fuel supply path 122 (122a, 122b) to the atmosphere, and controls the nitrogen gas introduction control solenoid valve 161 of the nitrogen gas introduction control mechanism 160 to connect the nitrogen gas introduction path 162 to the nitrogen gas supply path 132, allowing nitrogen gas from the nitrogen cylinder 131 to be introduced into the fuel supply path 122 (122a, 122b). As a result, the hydrogen gas remaining in the fuel supply path 122 (122a, 122b) is pushed out by the introduced nitrogen gas and discharged outside the machine through the air discharge path 154 (154a, 154b), and the gas in the fuel supply path 122 (122a, 122b) is replaced with nitrogen gas. [Prior art documents] [Patent documents]

[0034] [Patent Document 1] Japanese Patent Publication No. 2022-149336 Summary of the Invention [Problem to be solved by the invention]

[0035] 8, after the operation of the gaseous fuel engine unit 100 described above is stopped, high-pressure (1.0 to 14.7 MPa) and flammable hydrogen gas remains in the fuel supply path 122 (122a, 122b), and since leaving the flammable hydrogen gas therein poses a risk of fire, it is desirable to release the remaining hydrogen gas to the atmosphere. In the conventional example shown in the above-mentioned Fig. 8, in order to completely release the remaining hydrogen gas to the atmosphere, a nitrogen cylinder 131 is used to introduce inert nitrogen gas, which has a pressure higher than atmospheric pressure, into the fuel supply path 122 (122a, 122b), thereby pushing out the remaining hydrogen gas and replacing the hydrogen gas in the fuel supply path 122 (122a, 122b) with nitrogen gas (hereinafter referred to as "nitrogen replacement").

[0036] Furthermore, as in the above-mentioned gaseous fuel engine unit 100, it is desirable to use pneumatic valves rather than solenoid valves for explosion prevention purposes for the gaseous fuel supply valve 141 that controls the opening and closing of the fuel supply path 122 through which hydrogen, a flammable gas, can flow, and the air release valves 151 (151a, 151b) that control the opening and closing of the air release path 154 (154a, 154b) through which hydrogen, a flammable gas, can also flow. In the conventional example shown in Figure 8 above, nitrogen gas is used as the operating pressure for the pneumatic valve, and a nitrogen cylinder 131 is used as the operating pressure supply source.

[0037] However, when using a nitrogen cylinder 131 as a nitrogen gas supply source for nitrogen substitution and also as an operating pressure supply source, as in the conventional example shown in Figure 8, nitrogen gas is consumed not only every time nitrogen substitution is performed but also every time the air valve is opened and closed, so it is necessary to frequently replace the nitrogen cylinder 131, and replacing the nitrogen cylinder 131 is very time-consuming and costly.

[0038] Therefore, the present invention has been made in consideration of the shortcomings of the above-mentioned conventional technology, and aims to provide an apparatus and method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit, which can automatically discharge gaseous fuel remaining in the fuel supply line in an engine-driven compressor equipped with a gaseous fuel engine unit, and which can automatically generate nitrogen gas for the above-mentioned nitrogen replacement, and also nitrogen gas (operating pressure) that operates an air-operated valve. [Means for solving the problem]

[0039] The means for solving the problems are described below together with the reference numerals used in the description of the embodiment of the invention. These reference numerals are used to clarify the correspondence between the description of the claims and the description of the embodiment of the invention, and needless to say, are not used to restrict the interpretation of the technical scope of the present invention.

[0040] In order to achieve the above object, the residual gas fuel discharge device 12 in the engine-driven compressor 1 equipped with the gas fuel engine unit 10 of the present invention comprises: In an engine-driven compressor 1, there is provided a gaseous fuel engine unit 10, which is made up of a compressor main body 2 that sucks in and compresses a fluid to be compressed, an engine 13 that can use gaseous fuel as fuel and drives the compressor main body 2, and a fuel supply path 22 (primary fuel supply path 22a, secondary fuel supply path 22b) that supplies gaseous fuel from a gaseous fuel source 20 to the engine 13, and an air tank 3 that stores compressed gas discharged from the compressor main body 2, The gaseous fuel engine unit 10 includes: a nitrogen gas supply flow path 30 that is connected to the air tank 3 and that allows nitrogen gas purified from compressed air from the air tank 3 by a nitrogen gas purification device 32 installed in the flow path to be introduced into the fuel supply path 22 (22a, 22b); a gas fuel supply control mechanism 40 that opens and closes the gas fuel source 20 and the fuel supply path 22 (22a, 22b); an air release mechanism 50 that starts and stops the release of the fuel supply passage 22 (22a, 22b) to the atmosphere; a nitrogen gas introduction control mechanism 60 that opens and closes the nitrogen gas supply passage 30 and the fuel supply passage 22 (22a, 22b); a residual gaseous fuel discharge device (12) configured by a control device (70) consisting of an electronic control device that controls the operations of the gaseous fuel supply control mechanism (40), the gas release mechanism (50), and the nitrogen gas introduction control mechanism (60); The residual gas fuel discharge device 12 is configured by the control device 70 as follows: a gas fuel supply stop control means (74) for operating the gas fuel supply control mechanism (40) to cut off communication between the gas fuel source (20) and the fuel supply path (22) (22a, 22b) when the engine (13) is stopped, thereby executing a gas fuel supply stop process for stopping the supply of gas fuel to the fuel supply path (22); a fuel supply path fuel discharge control means (75) for executing a fuel supply path fuel discharge process for discharging the gaseous fuel remaining in the fuel supply path (22) (22a, 22b) into the atmosphere after the gaseous fuel supply stop control means (74) executes the gaseous fuel supply stop process; The fuel supply path fuel discharge control means 75 The gas release mechanism 50 is operated to open the fuel supply path 22 (22a, 22b) to the atmosphere, and in this state of being open to the atmosphere, the nitrogen gas introduction control mechanism 60 is operated to introduce nitrogen gas from the nitrogen gas supply flow path 30 into the fuel supply path 22 (22a, 22b), thereby performing fuel discharge processing within the fuel supply path (Claim 1: see Figure 1).

[0041] In the residual gas fuel discharge device 12 having the above configuration, The engine-driven compressor 1 is provided with a purge valve 6 that can release the compressed air stored in the air tank 3 into the atmosphere, and The nitrogen gas supply passage 30 is provided with a check valve CV on the secondary side of the nitrogen gas purifier 32, The gaseous fuel supply control mechanism 40 is composed of a gaseous fuel supply valve 41, which is an air-operated valve and opens and closes between the gaseous fuel source 20 and the fuel supply passage 22 (22a, 22b), a gaseous fuel supply valve control circuit 42 that introduces nitrogen gas from the nitrogen gas supply passage 30 into the gaseous fuel supply valve 41 as an operating pressure, and a gaseous fuel supply control electromagnetic valve 43 that connects and disconnects the nitrogen gas supply passage 30 and the gaseous fuel supply valve control circuit 42, The air release mechanism 50 is composed of at least one of an air release valve 51 (primary side air release valve 51a, secondary side air release valve 51b) which is an air-operated valve and opens the fuel supply path 22 (22a, 22b) to the atmosphere, or a single air release valve which is provided on the secondary side of the joining position of the air release path 54 (54a, 54b) in a configuration in which air release path 54 (54a, 54b) branching off from the primary side fuel supply path 22a and the secondary side fuel supply path 22b respectively is provided and the air release path 54 (54a, 54b) is joined along the way. ], an air release valve control circuit 52 (consisting of at least one of a primary side air release valve control circuit 52a, a secondary side air release valve control circuit 52b, or an air release valve control circuit that introduces nitrogen gas into the single air release valve) that introduces nitrogen gas from the nitrogen gas supply flow path 30 into the air release valve 51 as an operating pressure, and an air release valve control solenoid valve 53 that connects and blocks the nitrogen gas supply flow path 30 to the air release valve control circuit 52 (consisting of at least one of a primary side air release valve control solenoid valve 53a, a secondary side air release valve control solenoid valve 53b, or a single air release valve control solenoid valve that connects and blocks the nitrogen gas supply flow path 30 to both the primary side and secondary side air release valve control circuits 52a, 52b, or an air release valve control solenoid valve that connects and blocks the nitrogen gas supply flow path 30 to the single air release valve), The nitrogen gas introduction control mechanism 60 is composed of a nitrogen gas introduction flow path 62 that communicates between the nitrogen gas supply flow path 30 and the fuel supply path 22 (22a, 22b), and a nitrogen gas introduction control electromagnetic valve 61 that is provided between the nitrogen gas introduction flow path 62 and the nitrogen gas supply flow path 30, The gas fuel supply control solenoid valve 43 is configured to be operable by the gas fuel supply stop control means 74 of the control device 70, The air release valve control solenoid valve 53 and the nitrogen gas introduction control solenoid valve 61 may be configured to be operable by the fuel supply passage fuel discharge control means 75 of the control device 70 (claim 2: see FIG. 1).

[0042] In the residual gas fuel discharge device 12 having the above configuration, The nitrogen gas supply passage 30 may be provided with a pressure regulating section 82 that regulates the pressure of the nitrogen gas supplied from the nitrogen gas supply passage 30 to within the range of the operating pressure required to operate the gaseous fuel supply valve 41 and the air release valve 51, and may also be configured to have a pressure regulating mechanism 80 in which the check valve CV is arranged on the secondary side of the pressure regulating section 82 (Claim 3: see Figure 7).

[0043] In this case, the pressure adjustment mechanism 80 branches the nitrogen gas supply flow path 30 into three flow paths, and is composed of a flow path 80a for pressure reduction, which is provided with a pressure reducing valve 82a as the pressure adjustment section 82 and has the check valve CV1 arranged on the secondary side of the pressure reducing valve 82a, a flow path 80b for pressure increase, which is provided with a pressure increase valve 82b as the pressure adjustment section 82 and has the check valve CV2 arranged on the secondary side of the pressure increase valve 82b, and a flow path 80c for pressure adjustment not required, which does not have the pressure adjustment section 82 and has the check valve CV3 arranged therein, and the flow path 80a for pressure reduction, the flow path 80b for pressure increase, and the flow path 80c for pressure adjustment not required are joined together on the secondary sides of the check valves CV1, CV2, and CV3 within the nitrogen gas supply flow path 30, and The pressure regulating mechanism 80 is provided with a purified nitrogen gas pressure sensor 86 that is disposed on the secondary side of the nitrogen gas purifying device 32, detects the pressure of the nitrogen gas immediately after purification, and transmits a detection signal to the control device 70. The control device 70 When the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor 86 exceeds the upper limit of the required operating pressure, the pressure regulating mechanism 80 is operated to pass the nitrogen gas purified by the nitrogen gas purifier 32 through the pressure reducing flow path 80a, and the pressure of the nitrogen gas is reduced by the pressure reducing valve 82a to adjust the pressure within the required operating pressure range, When the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor 86 falls below the lower limit of the required operating pressure, the pressure regulating mechanism 80 is operated to pass the nitrogen gas purified by the nitrogen gas purifier 32 through the pressure-increasing flow path 80b, and the pressure of the nitrogen gas is increased by the pressure-increasing valve 82b to adjust the pressure within the required operating pressure range, The pressure adjustment control means 76 may be configured to operate the pressure adjustment mechanism 80 when the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor 86 is within the required operating pressure range, thereby performing a nitrogen gas pressure adjustment process in which the nitrogen gas purified by the nitrogen gas purification device 32 passes through the flow path 80c for when pressure adjustment is not required (Claim 4: see Figure 4).

[0044] In addition, in the pressure adjusting mechanism 80 having the above configuration, a pressure reducing solenoid valve 83a on the upstream side of the pressure reducing valve 82a in the pressure reducing flow path 80a, a pressure increasing solenoid valve 83b on the upstream side of the pressure increasing valve 82b in the pressure increasing flow path 80b, and a pressure adjustment not required solenoid valve 83c on the upstream side of the check valve CV3 in the pressure adjustment not required flow path 80c, The pressure reducing solenoid valve 83a, the pressure increasing solenoid valve 83b, and the pressure regulation unnecessary solenoid valve 83c may be configured to be operable by the pressure regulation control means 76 (claim 5: see FIG. 4).

[0045] In addition, in the residual gas fuel discharge device 12, The purge valve 6 is configured as an electromagnetic valve and is operable by the control device 70, The control device 70 may also be configured to implement a purge control means 78 that opens the purge valve 6 to release the compressed gas in the air tank 3 (claim 6).

[0046] Further, a pressure sensor 90 is provided on the secondary side of the check valve CV (CV1, CV2, CV3) to detect the pressure of the nitrogen gas in the nitrogen gas supply flow path 30 as a PV control pressure (PV: Pneumatic Valve) and transmit a detection signal to the control device 70, The purge control means 78 may be configured to open the purge valve 6 and perform the purge process when the PV control pressure is reduced by introducing nitrogen gas into the fuel supply path 22 (22a, 22b) during the fuel discharge process in the fuel supply path, and then when nitrogen gas is supplied from the air tank 3 via the nitrogen gas purification device 32 and the pressure sensor 90 detects that the PV control pressure has recovered (claim 7).

[0047] Furthermore, the method for discharging residual gaseous fuel in the engine-driven compressor 1 equipped with the gaseous fuel engine unit 10 of the present invention includes the following steps: In an engine-driven compressor 1, the compressor 1 is provided with a gaseous fuel engine unit 10, which is composed of a compressor main body 2 that sucks in and compresses a fluid to be compressed, an engine 13 that can use gaseous fuel as fuel and drives the compressor main body 2, and a fuel supply path 22 that supplies gaseous fuel from a gaseous fuel source 20 to the engine 13, and an air tank 3 that stores compressed gas discharged from the compressor main body 2. The gaseous fuel engine unit 10 is provided with a nitrogen gas supply flow path 30 that is connected to the air tank 3 and that allows nitrogen gas purified from compressed air from the air tank 3 by a nitrogen gas purification device 32 provided in the flow path to be introduced into the fuel supply path 22 (primary side fuel supply path 22a, secondary side fuel supply path 22b), a gas fuel supply stop process for stopping the supply of gas fuel from the gas fuel source 20 to the fuel supply path 22 (22a, 22b) when the engine 13 is stopped; After the gaseous fuel supply stop processing, a fuel discharge processing is performed in the fuel supply path to discharge the gaseous fuel remaining in the fuel supply path 22 (22a, 22b) into the atmosphere, The fuel discharge process in the fuel supply path is carried out by introducing nitrogen gas into the fuel supply path 22 (22a, 22b) through the nitrogen gas supply path 30 while the fuel supply path 22 (22a, 22b) is open to the atmosphere, thereby pushing out the gaseous fuel remaining in the fuel supply path 22 out of the fuel supply path 22 and replacing it with nitrogen gas (claim 8).

[0048] In the method for discharging residual gaseous fuel having the above configuration, The engine-driven compressor 1 is provided with a purge valve 6 that can release the compressed air stored in the air tank 3 into the atmosphere, The gaseous fuel engine unit 10 is equipped with a gaseous fuel supply valve 41 and an air release valve 51 (which are at least one of a primary side air release valve 51a, a secondary side air release valve 51b, or a single air release valve provided on the secondary side of the joining position of the air release flow path 54 (54a, 54b) in a configuration in which air release flow paths 54 (54a, 54b) branched from the primary side fuel supply path 22a and the secondary side fuel supply path 22b are provided and the air release flow paths 54 (54a, 54b) are joined midway), The nitrogen gas supply passage 30 is provided with a check valve CV on the secondary side of the nitrogen gas purifier 32, and is capable of supplying nitrogen gas as an operating pressure to the gas fuel supply valve 41 and the air release valve 51, The gaseous fuel supply stop processing stops the supply of gaseous fuel from the gaseous fuel source 20 to the fuel supply path 22 by stopping the introduction of nitrogen gas from the nitrogen gas supply flow path 30 to the gaseous fuel supply valve 41 and closing the gaseous fuel supply valve 41, and The fuel discharge process within the fuel supply path may be performed by starting the introduction of nitrogen gas from the nitrogen gas supply path 30 to the air release valve 51 and opening the air release valve 51, thereby discharging the gaseous fuel remaining within the fuel supply path 22 into the atmosphere (claim 9).

[0049] In addition, the method for discharging residual gaseous fuel of the present invention can include a nitrogen gas pressure adjustment process in the nitrogen gas supply passage 30, which adjusts the pressure of the nitrogen gas supplied from the nitrogen gas supply passage 30 to within the range of operating pressure required for the gaseous fuel supply valve 41 and the air release valve 51 to operate (Claim 10).

[0050] Furthermore, in the residual gas fuel discharge method of the present invention that includes the nitrogen gas pressure adjustment process, The pressure of the nitrogen gas immediately after purification on the secondary side of the nitrogen gas purification device 32 is detected, The nitrogen gas supply flow path 30 is branched into three flow paths, forming a flow path 80a for when pressure is reduced which is equipped with a pressure reducing valve 82a and the check valve CV1 is disposed on the secondary side of the pressure reducing valve 82a, a flow path 80b for when pressure is increased which is equipped with a pressure increasing valve 82b and the check valve CV2 is disposed on the secondary side of the pressure increasing valve 82b, and a flow path 80c for when pressure adjustment is not required which does not have a pressure adjusting unit 82 for adjusting the pressure of the nitrogen gas and in which the check valve CV3 is disposed within the flow path, and in this configuration the flow path 80a for when pressure is reduced, the flow path 80b for when pressure adjustment is not required and the flow path 80c for when pressure adjustment is not required are joined together on the secondary sides of the check valves CV1, CV2, and CV3 within the nitrogen gas supply flow path 30, The nitrogen gas pressure adjustment process is When the detected pressure of the nitrogen gas immediately after purification exceeds the upper limit of the required operating pressure, the nitrogen gas purified by the nitrogen gas purification device 32 is passed through the pressure reducing flow path 80a, and the pressure of the nitrogen gas is reduced by the pressure reducing valve 82a to adjust the pressure within the required operating pressure range, When the detected pressure of the nitrogen gas immediately after purification falls below the lower limit of the required operating pressure, the nitrogen gas purified by the nitrogen gas purification device 32 is passed through the pressure-increasing flow path 80b, and the pressure of the nitrogen gas is increased by the pressure-increasing valve 82b to adjust the pressure within the required operating pressure range, If the detected pressure of the nitrogen gas immediately after purification is within the range of the required operating pressure, the nitrogen gas purified by the nitrogen gas purification device 32 can be passed through the flow path 80c for when pressure adjustment is not required (Claim 11).

[0051] In addition, in the pressure adjusting mechanism 80 having the above configuration, a pressure reducing solenoid valve 83a on the upstream side of the pressure reducing valve 82a in the pressure reducing flow path 80a, a pressure increasing solenoid valve 83b on the upstream side of the pressure increasing valve 82b in the pressure increasing flow path 80b, and a pressure adjustment not required solenoid valve 83c on the upstream side of the check valve CV3 in the pressure adjustment not required flow path 80c, By operating the solenoid valve 83a for pressure reduction, the solenoid valve 83b for pressure increase, and the solenoid valve 83c for when pressure adjustment is not required, the nitrogen gas purified by the nitrogen gas purification device 32 can be passed through either the flow path 80a for pressure reduction, the flow path 80b for pressure increase, or the flow path 80c for when pressure adjustment is not required (Claim 12).

[0052] In addition, the method for discharging residual gaseous fuel of the present invention includes the following steps: It may also include a purging process in which the purge valve 6 is opened to release the compressed gas in the air tank 3 (claim 13).

[0053] In this case, in a configuration in which the pressure of nitrogen gas in the nitrogen gas supply passage 30 on the secondary side of the check valve CV (CV1, CV2, CV3) is detected as the PV control pressure, the purge process may be performed by introducing nitrogen gas into the fuel supply passage 22 (22a, 22b) during the fuel discharge process in the fuel supply passage, thereby reducing the PV control pressure, and then opening the purge valve 6 when nitrogen gas is supplied from the air tank 3 via the nitrogen gas purification device 32 and recovery of the PV control pressure is detected (Claim 14). [Effects of the Invention]

[0054] According to the configuration of the present invention described above, the residual gaseous fuel discharge device and discharge method in the engine-driven compressor 1 equipped with the gaseous fuel engine unit 10 of the present invention, in order to perform the nitrogen replacement described above, nitrogen gas is purified from the compressed air generated from the compressor main body 2 by the nitrogen gas purification device 32 and used, so there is no need to prepare a nitrogen cylinder.Furthermore, in the present invention, nitrogen gas is generated automatically at all times when the compressor is operating, so there is no need to go through the trouble of replacing the conventional nitrogen cylinder, and costs can be reduced.

[0055] Furthermore, in a configuration in which air-operated valves that operate by nitrogen gas pressure are used as the gas fuel supply valve 41 and the air release valve 51 that control the opening and closing of the flow path of gaseous fuel, which is a flammable gas, explosion prevention is improved compared to when solenoid valves are used, and by supplying nitrogen gas as the operating pressure to the air-operated valve through the nitrogen gas supply flow path 30, the nitrogen cylinder that was previously required as the operating pressure source is no longer necessary.

[0056] Furthermore, in the above configuration, since the nitrogen gas supply flow path 30 is equipped with a check valve CV, even after the purge valve 6 is opened to release the compressed air in the air tank 3 when operation is stopped, nitrogen gas remains in the nitrogen gas supply flow path 30 on the secondary side of the check valve CV (residual pressure is maintained), so that the remaining nitrogen gas can be used to operate the air valve the next time operation is started.

[0057] In addition, in a configuration in which the pressure of the nitrogen gas in the nitrogen gas supply passage 30 is adjusted to within the range of the required operating pressure to operate the air valves (gaseous fuel supply valve 41 and air release valve 51), even if the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 is not constant within the range of the required operating pressure, it is possible to supply a constant amount of nitrogen gas within the range of the required operating pressure to the air valve.

[0058] In particular, in a configuration in which the pressure of the nitrogen gas immediately after purification by the nitrogen gas purification device 32 is detected and the above-mentioned flow path 80a for pressure reduction, flow path 80b for pressure increase, and flow path 80c for when pressure adjustment is not required are provided, the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 can be adjusted to within the range of the operating pressure required to operate the air valve, even when the upper and lower limits of the required operating pressure of the air valve are set.

[0059] Furthermore, in a configuration in which purging is performed after detecting the recovery of the PV control pressure, sufficient operating pressure (nitrogen gas) was able to be maintained even after purging to operate the air valve the next time operation was started. [Brief explanation of the drawings]

[0060] [Figure 1]Fig. 1(a) is an explanatory diagram of an engine-driven compressor equipped with a gaseous fuel engine unit having a residual gaseous fuel discharge device of Example 1. Figs. 1(b) and 1(c) are cut-out views of a portion of Fig. 1(a). [Figure 2] 1 is a functional block diagram of a residual gaseous fuel discharge device of a gaseous fuel engine unit according to a first embodiment. [Figure 3] FIG. 3 is a flow chart showing the operation of the residual gaseous fuel discharge device of the gaseous fuel engine unit of the first embodiment. [Figure 4] Fig. 1(a) is an explanatory diagram of an engine-driven compressor equipped with a gaseous fuel engine unit having a residual gaseous fuel discharge device of Example 2. Fig. 1(b) is a cut-out diagram of a part of Fig. 1(a). [Figure 5] FIG. 10 is a functional block diagram of a residual gaseous fuel discharge device of a gaseous fuel engine unit according to a second embodiment. [Figure 6] 5 is a time chart showing the operation of each part of the engine-driven compressor of the second embodiment. [Figure 7] FIG. 10 is an explanatory diagram of an engine-driven compressor equipped with a gaseous fuel engine unit having a residual gaseous fuel discharge device according to a third embodiment. [Figure 8] An explanatory diagram (Fig. (a)) of a gaseous fuel engine unit equipped with a residual gaseous fuel discharge device according to the applicant's earlier application, and Figs. (b) and (c) are cut-outs of a portion of Fig. (a). DETAILED DESCRIPTION OF THE INVENTION

[0061] Hereinafter, the configuration of the residual gaseous fuel discharge device 12 in the engine-driven compressor 1 equipped with the gaseous fuel engine unit 10 of the present invention will be described with reference to the accompanying drawings.

[0062] In the following explanation, we will use an example of using hydrogen gas as gaseous fuel, but the application of the present invention is not limited to gaseous fuel engine units (hydrogen engine units) that use hydrogen gas as fuel, and it can also be applied to gaseous fuel engine units that use other known gaseous fuels such as natural gas as fuel.

[0063] [Overall configuration of engine-driven compressor] 1 is an engine-driven compressor of the present invention, and this engine-driven compressor 1 comprises a compressor main body 2 that sucks in and compresses the fluid to be compressed, a gaseous fuel engine unit 10 having an engine 13 that drives the compressor main body 2, an intake valve 4 that opens and closes the intake port of the compressor main body 2, and an air tank (receiver tank) 3 that stores the compressed gas discharged from the compressor main body 2, and is configured so that the compressed gas discharged from the compressor main body 2 can be stored in the air tank 3 and then supplied to a pneumatic work machine or the like (not shown) connected to a service valve 5. The engine-driven compressor 1 also comprises a purge valve 6 that can release the compressed air stored in the air tank 3 into the atmosphere.

[0064] [Overall configuration of gaseous fuel engine unit] With reference to FIG. 1, a gaseous fuel engine unit (hydrogen engine unit) 10 provided in an engine-driven compressor 1 will be described.

[0065] In Figure 1, the symbol 10 denotes a gaseous fuel engine unit (hydrogen engine unit) equipped with a residual gaseous fuel discharge device 12 described below, and this gaseous fuel engine unit 10 is equipped with an engine 13 as an internal combustion engine that operates by burning hydrogen gas, which is a gaseous fuel, and a fuel supply path (hydrogen gas supply path) 22 that supplies hydrogen gas from a gaseous fuel source (hydrogen source) 20 to the engine 13.

[0066] In this embodiment, the engine 13 is configured as a hydrogen-only engine that operates using only hydrogen gas as fuel, but the present invention can also be applied to a gas fuel engine unit 10 that is configured with a liquid fuel supply passage (not shown) that supplies liquid fuel such as diesel or gasoline to the engine 13, allowing it to operate by selectively supplying hydrogen fuel and liquid fuel, or by simultaneously supplying hydrogen fuel and liquid fuel.

[0067] In the illustrated example, the gaseous fuel source 20 is constituted by a hydrogen gas cylinder, but instead of this configuration, a tank filled with liquefied hydrogen may be used as the hydrogen source, and in this case, the gaseous fuel source 20 may include, along with the liquefied hydrogen tank, a vaporizer for vaporizing the liquefied hydrogen to obtain hydrogen gas.

[0068] As shown in Figure 1, the fuel supply path 22 is provided with a gaseous fuel pressure regulator 24 at its intermediate position, which adjusts the pressure of the hydrogen gas to a predetermined pressure (reducing the pressure in this embodiment), and in this embodiment, the primary (high pressure) side of this gaseous fuel pressure regulator 24 is called the primary side fuel supply path 22a, and the secondary (low pressure) side is called the secondary side fuel supply path 22b.

[0069] Further, a gaseous fuel supply valve 41 of a gaseous fuel supply control mechanism 40, which will be described later, is provided in the fuel supply path 22. In the illustrated example, the gaseous fuel supply valve 41 (gaseous fuel control mechanism 40) is provided in the primary fuel supply path 22a, but it may also be provided in the secondary fuel supply path 22b, or further, it may be provided in both the primary fuel supply path 22a and the secondary fuel supply path 22b.

[0070] The gaseous fuel supply valve 41 is opened and closed to control communication between the gaseous fuel source 20 and the fuel supply path 22 .

[0071] As shown in FIG. 1, the fuel supply path 22 may be provided with a check valve cv1 on the primary side of the gas fuel supply valve 41, and the check valve cv1 may be used to prevent the gas in the fuel supply path 22 from flowing into the gas fuel source 20.

[0072] Furthermore, the gaseous fuel pressure regulator 24 may be provided at a position closer to the gaseous fuel source 20, and its placement is not limited to the position shown in the figure. If the gaseous fuel source 20 is provided with a pressure adjustment means such as a pressure regulator, the installation of the pressure regulator 24 on the fuel supply path 22 can be omitted.

[0073] Next, the engine 13, which receives gaseous fuel via the fuel supply path 22, is provided with an engine control unit (ECU) 14 (not shown) that controls the operation of the engine 13 and a starter motor (not shown) for starting the engine 13, and is configured so that the engine 13 can be started, stopped, and its speed controlled by a control device 70 consisting of an electronic control device such as a microcontroller provided in the gaseous fuel engine unit 10.

[0074] [Residual gas fuel discharge device] (Example 1) (1) Overall structure The gaseous fuel engine unit 10 configured as described above is provided with a residual gaseous fuel discharge device 12 that discharges hydrogen gas remaining in the fuel supply path 22 described above when the compressor is stopped, or discharges hydrogen gas remaining in the fuel supply path 22 to the outside of the machine. The residual gaseous fuel discharge device 12 introduces nitrogen gas purified from compressed air from the air tank 3 by a nitrogen gas purification device 32 provided midway through the path into the fuel supply path 22, and is also provided with a nitrogen gas supply path 30 that supplies nitrogen gas as operating pressure to an air valve described below.

[0075] Furthermore, the residual gaseous fuel discharge device 12 is composed of a gaseous fuel supply control mechanism 40 that opens and closes between the hydrogen source 20 and the fuel supply path 22 to control the start and stop of the introduction of hydrogen gas into the fuel supply path 22, an air release mechanism 50 (50a, 50b) that controls the start and stop of opening the fuel supply path 22 to the atmosphere, a nitrogen gas introduction control mechanism 60 that opens and closes between the nitrogen gas supply passage 30 and the fuel supply path 22 to control the start and stop of the introduction of nitrogen gas into the fuel supply path 22, and a control device 70 that controls the operation of the gaseous fuel supply control mechanism 40, the air release mechanism 50 (50a, 50b), and the nitrogen gas introduction control mechanism 60.

[0076] (2) Nitrogen gas supply channel 30 The nitrogen gas supply flow path 30 is a flow path that is connected to the air tank 3 and supplies nitrogen gas purified from compressed air from the air tank 3 by a nitrogen gas purification device 32 installed along the way to replace nitrogen in the fuel supply path 22, and also supplies it as operating pressure to the gas fuel supply valve 41 and air release valve 51 (primary side air release valve 51a, secondary side air release valve 51b) consisting of an air valve (air-operated opening / closing valve) described later.

[0077] As described above, the present invention utilizes nitrogen gas purified from compressed air generated by the compressor body 2 by the nitrogen gas purification device 32, which is used as nitrogen gas for replacing the inside of the fuel supply path 22 with nitrogen and as nitrogen gas for operating the air-operated valve. In the example shown in Fig. 1, the nitrogen gas supply path 30 is provided with a check valve CV on the secondary side of the nitrogen gas purification device 32 to maintain residual pressure, and is branched into four on the secondary side of the check valve CV, which are connected to a gas fuel supply control solenoid valve 43, an air release valve control solenoid valve 53 (53a, 53b), and a nitrogen gas introduction control solenoid valve 61, which will be described later.

[0078] Even after the compressed air in the air tank 3 is purged by the check valve CV, nitrogen gas remains in the nitrogen gas supply flow path 30 on the secondary side of the check valve CV (residual pressure is maintained).

[0079] Furthermore, the nitrogen gas purifier 32 may be a known nitrogen gas purifier that purifies nitrogen gas by separating it from components in compressed air using a molecular sieve.

[0080] (3) Gaseous fuel supply control mechanism 40 The reference numeral 40 in FIG. 1 denotes a gaseous fuel supply control mechanism, which controls the start and stop of supply of hydrogen gas to the fuel supply path 22 by connecting or blocking communication between the gaseous fuel source 20 and the fuel supply path 22.

[0081] In the illustrated embodiment, the gas fuel supply control mechanism 40 is composed of a gas fuel supply valve 41 consisting of an air-operated valve provided in the fuel supply path 22, a gas fuel supply valve control circuit 42 that introduces nitrogen gas from the nitrogen gas supply path 30 as operating pressure into this gas fuel supply valve 41, and a gas fuel supply control solenoid valve 43 consisting of a solenoid valve (three-way solenoid valve) that connects this gas fuel supply valve control circuit 42 to the nitrogen gas supply path 30 or opens it to the atmosphere.

[0082] In this way, explosion prevention is achieved by using an air-operated valve that operates by the pressure of nitrogen gas (inert gas) rather than a solenoid valve for the gas fuel supply valve 41 that controls the opening and closing of the flow path of gas fuel, which is a flammable gas, while a solenoid valve is used for the gas fuel supply control solenoid valve 43 that opens and closes the flow path of nitrogen gas, which does not require explosion prevention, making it easier to electrically control it using the control device 70, which will be described later.

[0083] By providing the gas fuel supply control mechanism 40 having the above-described configuration, when the gas fuel supply control solenoid valve 43 is operated to connect the nitrogen gas supply flow path 30 to the gas fuel supply valve control circuit 42, nitrogen gas is introduced into the gas fuel supply valve 41 as an operating pressure, causing the gas fuel supply valve 41 to open and introducing hydrogen gas, which is the gas fuel, into the fuel supply path 22.

[0084] On the other hand, when the gas fuel supply control solenoid valve 43 is operated to cut off communication between the nitrogen gas supply passage 30 and the gas fuel supply valve control circuit 42 and the gas fuel supply valve control circuit 42 is opened to the atmosphere, the introduction of operating pressure (nitrogen gas) to the gas fuel supply valve 41 is stopped, and the gas fuel supply valve 41 is closed by the force of the return spring, thereby stopping the introduction of hydrogen gas to the fuel supply passage 22.

[0085] (4) Air release mechanism 50 The air release mechanism 50 controls the start and stop of the opening of the fuel supply passage 22 (22a, 22b) to the atmosphere.

[0086] In the embodiment shown in FIG. 1, air discharge passages 54 (54a, 54b) branching off from the primary fuel supply passage 22a and the secondary fuel supply passage 22b are provided, and the air discharge passages 54 (54a, 54b) are extended to the outside of the aircraft.

[0087] Each air release flow path 54 (54a, 54b) is controlled to open and close by the air release mechanism 50 (primary side air release mechanism 50a, secondary side air release mechanism 50b), thereby making it possible to start or stop opening the fuel supply path 22 (22a, 22b) to the atmosphere.

[0088] The opening and closing of the air release flow path 54 (54a, 54b) through which hydrogen, a flammable gas, can flow is performed by an air release valve 51 (primary side air release valve 51a, secondary side air release valve 51b) which is composed of an air-operated valve that operates using nitrogen gas introduced from the nitrogen gas supply flow path 30 as its operating pressure for explosion prevention purposes, and the aforementioned air release mechanism 50 (primary side air release mechanism 50a, secondary side air release mechanism 50b) is constituted by an air release valve control circuit 52 (primary side air release valve control circuit 52a, secondary side air release valve control circuit 52b) which introduces nitrogen gas as the operating pressure to the air release valve 51 (51a, 51b), and an air release valve control solenoid valve 53 (primary side air release valve control solenoid valve 53a, secondary side air release valve control solenoid valve 53b) which is composed of a three-way solenoid valve that connects this air release valve control circuit 52 (52a, 52b) to the nitrogen gas supply flow path 30 or opens it to the atmosphere.

[0089] As a result, when the air release valve control solenoid valve 53 (53a, 53b) connects the air release valve control circuit 52 (52a, 52b) to the nitrogen gas supply flow path 30, nitrogen gas (operating pressure) is introduced into the air release valve 51 (51a, 51b), and the air release valve 51 (51a, 51b) opens, thereby starting to open the fuel supply path 22 (22a, 22b) to the atmosphere.

[0090] On the other hand, when the air release valve control solenoid valve 53 (53a, 53b) cuts off the communication between the air release valve control circuit 52 (52a, 52b) and the nitrogen gas supply flow path 30 and opens the air release valve control circuit 52 (52a, 52b) to the atmosphere, the introduction of nitrogen gas stops and the air release valve 51 (51a, 51b) closes due to the force of the return spring, thereby stopping the opening of the fuel supply path 22 (22a, 22b) to the atmosphere.

[0091] In the illustrated example, a primary side air release valve 51a and a secondary side air release valve 51b are provided in the air release flow path 54 (54a, 54b), respectively, and a primary side air release valve control solenoid valve 53a and a secondary side air release valve control solenoid valve 53b are provided to control the start and stop of the introduction of nitrogen gas into the primary side air release valve 51a and the secondary side air release valve 51b, respectively. However, instead of this configuration, for example, the start and stop of the introduction of nitrogen gas into both the primary side air release valve 51a and the secondary side air release valve 51b may be controlled by a single air release valve. It may be controlled by a control solenoid valve, or a single air release valve may be provided on the secondary side of the confluence of the air release flow paths 54 (54a, 54b), and a single air release valve control solenoid valve may be provided to control the start and stop of the introduction of nitrogen gas into this air release valve.The configuration of the air release mechanism 50 (50a, 50b) is not limited to the configuration shown in the figure, as long as it is configured to be able to control the start and stop of opening the primary side fuel supply path 22a and the secondary side fuel supply path 22b to the atmosphere.

[0092] (5) Nitrogen gas introduction control mechanism 60 The nitrogen gas introduction control mechanism 60 in the figure controls the start and stop of the introduction of nitrogen gas from the nitrogen gas supply flow path 30 to the fuel supply path 22 (22a, 22b), and is composed of a nitrogen gas introduction flow path 62 that introduces nitrogen gas from the nitrogen gas supply flow path 30 to the fuel supply path 22 (22a, 22b), and a nitrogen gas introduction control solenoid valve 61 that is located between this nitrogen gas introduction flow path 62 and the nitrogen gas supply flow path 30 and connects or blocks each other.

[0093] 1, the nitrogen gas introduction flow path 62 branches into two on the secondary side, one of which is connected to the primary-side fuel supply path 22a via a check valve cv2, and the other of which is connected to the secondary-side fuel supply path 22b via a check valve cv3. By connecting the nitrogen gas introduction flow path 62 to the fuel supply path 22 (22a, 22b) via the check valves cv2 and cv3 in this way, hydrogen gas in the fuel supply path 22 (22a, 22b) is prevented from flowing into the nitrogen gas introduction flow path 62.

[0094] In addition, the nitrogen gas introduction control solenoid valve 61, which controls the opening and closing of the nitrogen gas introduction flow path 62, is composed of an electromagnetic opening and closing valve (two-way solenoid valve) because there is no need for explosion protection, and by opening and closing the nitrogen gas introduction control solenoid valve 61, the introduction of nitrogen gas from the nitrogen gas supply flow path 30 to the fuel supply path 22 (22a, 22b) can be started and stopped via the nitrogen gas introduction flow path 62.

[0095] (6) Control device 70 The control device 70 is composed of an electronic control device such as a microcontroller, and in addition to controlling the operation of each part of the engine-driven compressor 1 and the operation of the engine 13 described above, by executing a pre-stored program, the control device 70 realizes each means shown in the functional block diagram of Figure 2, thereby controlling the operation of the gas fuel supply control mechanism 40, the air release mechanism 50 (50a, 50b), and the nitrogen gas introduction control mechanism 60 described above.

[0096] In the embodiment shown in Figures 1 and 2, the operation of each solenoid valve (gaseous fuel supply control solenoid valve 43, air release valve control solenoid valve 53 (53a, 53b), nitrogen gas introduction control solenoid valve 61) provided in the aforementioned gas fuel supply control mechanism 40, air release mechanism 50 (50a, 50b), and nitrogen gas introduction control mechanism 60 is electrically controlled by the following means, and the following processes are executed.

[0097] (6-1) Gaseous fuel supply stop control means 74 (gaseous fuel supply stop processing) In response to a command to stop the engine 13 (for example, by an operator operating an operation stop switch), the control device 70 activates the gas fuel supply stop control means 74 to stop the supply of hydrogen gas to the engine 13 in order to stop the engine 13.

[0098] The gaseous fuel supply stop control means 74 controls the operation of the gaseous fuel supply control mechanism 40 to stop the supply of gaseous fuel from the gaseous fuel source 20 to the fuel supply path 22, thereby executing a gaseous fuel supply stop process.

[0099] In the configuration of the embodiment shown in Figure 1, when executing the gas fuel supply stop processing, the gas fuel supply stop control means 74 controls the gas fuel supply control solenoid valve 43 of the gas fuel supply control mechanism 40 to block communication between the nitrogen gas supply flow path 30 and the gas fuel supply valve control circuit 42.

[0100] This stops the introduction of nitrogen gas (operating pressure) into the gaseous fuel supply valve 41, causes the gaseous fuel supply valve 41 to close due to the force of the return spring, and stops the supply of hydrogen gas, which is the gaseous fuel, from the gaseous fuel source 20 to the fuel supply path 22.

[0101] The gas fuel supply stop control means 74 maintains the operation of the gas fuel supply control mechanism 40, i.e., the position of the gas fuel supply control solenoid valve 43, in a state in which the supply of hydrogen gas to the fuel supply path 22 is stopped until a new command to start the engine 13 is received.

[0102] (6-2) Fuel supply path fuel discharge control means 75 (fuel supply path fuel discharge processing) Simultaneously with or after the execution of the gas fuel supply stop processing described above, the control device 70 activates the fuel discharge control means 75 in the fuel supply path to execute a fuel discharge processing in the fuel supply path, which discharges the gas fuel remaining in the fuel supply path 22 (22a, 22b) into the atmosphere.

[0103] In this embodiment, the fuel discharge control means 75 in the fuel supply path controls the air release valve control solenoid valves 53 (53a, 53b) provided in the air release mechanisms 50 (50a, 50b) to connect the air release valve control circuits 52 (52a, 52b) to the nitrogen gas supply flow path 30, thereby introducing nitrogen gas as an operating pressure into the air release valves 51 (51a, 51b), thereby opening the air release valves 51 (51a, 51b) and opening the fuel supply path 22 (22a, 22b) to the atmosphere.

[0104] Furthermore, the fuel supply path fuel discharge control means 75 controls and opens the nitrogen gas introduction control electromagnetic valve 61 that constitutes the nitrogen gas introduction control mechanism 60, thereby introducing nitrogen gas from the nitrogen gas supply path 30 into the fuel supply path 22 (22a, 22b) via the nitrogen gas introduction path 62. The timing for opening the nitrogen gas introduction control electromagnetic valve 61 only needs to be such that the air release valves 51 (51a, 51b) are open (the fuel supply path 22 is open to the atmosphere), and therefore it can be any time after the air release valves 51 (51a, 51b) are opened.

[0105] By introducing nitrogen gas into the above-mentioned fuel supply passage 22 (22a, 22b), the hydrogen gas, which is the gaseous fuel remaining in the fuel supply passage 22 (22a, 22b), is pushed out by the introduced nitrogen gas and discharged outside the aircraft through the air discharge flow passage 54 (54a, 54b), and the gas in the fuel supply passage 22 (22a, 22b) is replaced with nitrogen gas (nitrogen replacement).

[0106] When a predetermined discharge termination condition is satisfied, the fuel supply path fuel discharge control means 75 operates the air release mechanism 50 (50a, 50b) to terminate the opening of the fuel supply path 22 to the atmosphere, thereby completing the fuel supply path fuel discharge process.

[0107] For example, when a preset discharge time has elapsed since the start of the introduction of nitrogen gas into the fuel supply path 22 (22a, 22b) has been counted by a timer (not shown) provided in the control device 70, the fuel discharge control means 75 in the fuel supply path operates the air release valve control solenoid valve 53 (53a, 53b) provided in the air release mechanism 50 (50a, 50b) to block communication between the air release valve control circuit 52 (52a, 52b) and the nitrogen gas supply flow path 30, and opens the air release valve control circuit 52 (52a, 52b) to the atmosphere, thereby closing the air release valve 51 (51a, 51b) and terminating the opening of the fuel supply path 22 (22a, 22b) to the atmosphere, and closes the nitrogen gas introduction control solenoid valve 61 to stop the introduction of nitrogen gas into the fuel supply path 22 (22a, 22b), thereby terminating the fuel discharge process in the fuel supply path.

[0108] Furthermore, instead of the timer, a hydrogen concentration detector (not shown) may be provided to detect the hydrogen concentration in the fuel supply path 22 (22a, 22b) or the hydrogen concentration in the air discharge flow path 54 (54a, 54b) communicating with the fuel supply path 22 (22a, 22b), and when the hydrogen concentration in the fuel supply path 22 (22a, 22b) or the air discharge flow path 54 (54a, 54b) becomes less than a predetermined threshold value C1 (for example, a hydrogen concentration less than 4%), the fuel supply path fuel discharge process (opening the fuel supply path 22 (22a, 22b) to the atmosphere and introducing nitrogen gas into the fuel supply path 22 (22a, 22b)) by the fuel supply path fuel discharge control means 75 may be terminated.

[0109] (6-3) Other measures In addition, the stop condition determination means 71 in Figure 2 monitors and determines whether the conditions for stopping the engine 13 are met (for example, whether the operator has operated the stop switch) while the engine 13 is operating.

[0110] Furthermore, when the stop condition determination means 71 determines that the stop condition is satisfied, the engine stop control means 72 outputs a stop command to the engine 13 (ECU 14 of the engine 13) and executes processing to stop the engine 13.

[0111] In addition, if the purge valve 6 is an electromagnetic valve, the purge control means 78 electrically controls the operation of the purge valve 6, opens the purge valve 6 when the engine-driven compressor 1 is stopped, etc., and performs a purge process to release the compressed gas in the air tank 3.

[0112] [Operation of the residual gas fuel discharge device, etc.] The operation of the gaseous fuel engine unit 10 equipped with the residual gaseous fuel discharge device 12 configured as above will be described with reference to FIG.

[0113] While the engine 13 is operating, the stop condition determination means 71 of the control device 70 monitors and determines whether or not the conditions for stopping the engine 13 (stop conditions) are met (S1 in FIG. 3).

[0114] As an example, the stop condition determination means 71 may determine that the above-mentioned stop condition is satisfied when the operation stop switch is operated by the operator, or, if the gas fuel engine unit 10 requires cooling operation when the engine 13 is stopped, may determine that the above-mentioned stop condition is satisfied when the operation stop switch is operated by the operator and the specified cooling operation is completed, and the above-mentioned stop condition can be set in various ways depending on the specifications of the gas fuel engine unit 10.

[0115] If the stop condition is not satisfied (No in S1 of FIG. 3), the stop condition determination means 71 continues to monitor whether or not the stop condition is satisfied.

[0116] On the other hand, when the stop condition determination means 71 determines that the stop condition is satisfied (Yes in S1 of Figure 3), the engine stop control means 72 outputs a stop command for the engine 13 to the ECU 14 of the engine 13 to execute the stop processing for the engine 13 (S2 of Figure 3), and the following processing is performed by the gas fuel supply stop control means 74 and the fuel discharge control means 75 in the fuel supply path.

[0117] The gas fuel supply stop control means 74 stops the introduction of gas fuel into the fuel supply path 22 (22a, 22b) by closing the gas fuel supply control solenoid valve 43 to stop the introduction of nitrogen gas into the gas fuel supply valve 41 and closing the gas fuel supply valve 41 (S3 in Figure 3).

[0118] In addition, the fuel discharge control means 75 in the fuel supply path opens the air release valve control solenoid valve 53 (53a, 53b) to start the introduction of nitrogen gas into the air release valve 51 (51a, 51b), and by opening the air release valve 51 (51a, 51b), opens the fuel supply path 22 (22a, 22b) to the atmosphere via the air release flow path 54 (54a, 54b) (S4 in Figure 3), and also opens the nitrogen gas introduction control solenoid valve 61 to start the introduction of nitrogen gas into the fuel supply path 22 (22a, 22b) (S5 in Figure 3).

[0119] In this way, with the supply of hydrogen gas to the fuel supply path 22 stopped and with the fuel supply path 22 (22a, 22b) open to the atmosphere via the air release flow path 54 (54a, 54b), nitrogen gas is introduced into the fuel supply path 22 (22a, 22b), so that the hydrogen gas remaining in the fuel supply path 22 (22a, 22b) is pushed out by the nitrogen gas and released into the atmosphere, and the gas in the fuel supply path 22 (22a, 22b) is replaced from hydrogen gas to nitrogen gas, which is an inert gas.

[0120] If the control device 70 is provided with the timer described above, it continues counting from the start of the introduction of nitrogen gas into the fuel supply path 22 (22a, 22b) (S5 in FIG. 3) until a predetermined discharge time t1 has elapsed (loop of No in S6 in FIG. 3), and when the predetermined discharge time t1 has elapsed (Yes in S6 in FIG. 3), the fuel supply path fuel discharge control means 75 terminates the fuel discharge process in the fuel supply path.

[0121] In addition, if a hydrogen concentration detector is provided instead of a timer to detect the hydrogen concentration in the fuel supply path 22 (22a, 22b) or the hydrogen concentration in the air discharge flow path 54 (54a, 54b) connected to the fuel supply path 22 (22a, 22b), the fuel discharge process in the fuel supply path by the fuel supply path fuel discharge control means 75 (opening the fuel supply path 22 (22a, 22b) to the atmosphere and introducing nitrogen gas into the fuel supply path 22 (22a, 22b)) is terminated when the hydrogen concentration in the fuel supply path 22 or the air discharge flow path 54 (54a, 54b) becomes less than a predetermined threshold C1 (for example, a hydrogen concentration of less than 4%) (not shown).

[0122] This fuel discharge process within the fuel supply path is terminated when the fuel supply path fuel discharge control means 75 closes the air release valve control solenoid valve 53 (53a, 53b) to cut off communication between the nitrogen gas supply flow path 30 and the air release valve control circuit 52 (52a, 52b), opens the air release valve control circuit 52 (52a, 52b) to the atmosphere, and closes the air release valve 51 (51a, 51b), thereby terminating the opening of the fuel supply path 22 (22a, 22b) to the atmosphere and closing the nitrogen gas introduction control solenoid valve 61 to terminate the introduction of nitrogen gas into the fuel supply path 22 (22a, 22b) (S7 in Figure 3).

[0123] This completes the process of discharging the remaining gaseous fuel (END in FIG. 3).

[0124] Furthermore, upon completion of the above-mentioned process of discharging the residual gaseous fuel, the purge control means 78 opens the purge valve 6, and the compressed air in the air tank 3 is released to complete the purge process (not shown in Figure 3).Even after this, nitrogen gas remains in the nitrogen gas supply passage 30 on the secondary side of the check valve CV due to the check valve CV.

[0125] Therefore, the next time the engine-driven compressor 1 is started, the gas fuel supply control solenoid valve 43 is controlled to connect the nitrogen gas supply passage 30 to the gas fuel supply valve control circuit 42, and the remaining nitrogen gas mentioned above is introduced into the gas fuel supply valve 41 to open the gas fuel supply valve 41, thereby starting the introduction of gas fuel into the fuel supply passage 22 and making it possible to supply gas fuel (hydrogen gas) to the engine 13.

[0126] In addition, the purge control means 78 may be provided with a pressure sensor 90 (not shown in Figure 1) that detects the pressure of nitrogen gas in the nitrogen gas supply passage 30 on the secondary side of the check valve CV (hereinafter referred to as the "PV control pressure"; PV: Pneumatic Valve) and transmits a detection signal to the control device 70, so that after the PV control pressure decreases by introducing nitrogen gas into the fuel supply passage 22 during the fuel discharge process in the fuel supply passage, nitrogen gas is supplied from the air tank 3 via the nitrogen gas purification device 32, and the pressure sensor 90 detects the recovery of the PV control pressure, causing the purge control means 78 to open the purge valve 6 and perform a purge process to release the compressed air in the air tank 3.

[0127] [Modification 1 of the residual gas fuel discharge device] (Embodiment 2) Next, another embodiment (embodiment 2) of the engine-driven compressor 1 will be described, but the configuration of the engine-driven compressor in this embodiment is the same as that of embodiment 1 described with reference to Figures 1 to 3 except for the configuration described below, and therefore description thereof will be omitted. Furthermore, parts corresponding to embodiment 1 will be described with the same reference numerals.

[0128] In this embodiment, the air-operated valves constituting the gaseous fuel supply valve 41 and the air release valve 51 (51a, 51b) have a set operating pressure, i.e., a range of required operating pressure (in this embodiment, upper and lower limits of the required operating pressure are set. For example, they operate in a range of 0.4 to 0.6 MPa). In order to deal with cases where the pressure in the air tank 3 is not constant within the range of required operating pressure, for example, due to large fluctuations in the amount of compressed air consumed by the pneumatic work machine or the use of a compressor whose rated pressure can be changed as appropriate, the residual gaseous fuel discharge device 12 in this embodiment is equipped with a pressure regulating mechanism 80 that can adjust the pressure of the nitrogen gas in the nitrogen gas supply passage 30 to within the range of required operating pressure and constantly supply nitrogen gas (operating pressure) within the range of required operating pressure to the gaseous fuel supply valve 41 and the air release valve 51 (51a, 51b) which are air-operated valves.

[0129] (1) Pressure adjusting mechanism 80 The pressure adjustment mechanism 80 of the present invention is provided on the secondary side of the nitrogen gas purification device 32 of the nitrogen gas supply flow path 30, and is equipped with a pressure adjustment section 82 that adjusts the pressure of the passing nitrogen gas to within the required operating pressure range, and a check valve CV is arranged on the secondary side of the pressure adjustment section 82.The pressure adjustment mechanism 80 illustrated in Figure 4 branches into three flow paths midway along the nitrogen gas supply flow path 30, and is composed of a first flow path, a pressure reduction flow path 80a that controls the pressure reduction of the introduced nitrogen gas using the pressure adjustment section 82 (pressure reduction valve 82a), a second flow path, a pressure increase flow path 80b that controls the pressure increase of the introduced nitrogen gas using the pressure adjustment section 82 (pressure increase valve 82b), and a third flow path, a pressure adjustment not required flow path 80c, into which nitrogen gas that does not have a pressure adjustment section 82 and does not require pressure adjustment is introduced.

[0130] The pressure reducing flow path 80a is provided with a pressure reducing solenoid valve 83a, a pressure reducing valve (regulator) 82a, and a check valve CV1 in this order from upstream to downstream. The pressure reducing valve 82a used as the pressure adjusting unit 82 is a known one, which reduces the pressure of nitrogen gas that exceeds the upper limit of the required operating pressure, and adjusts the pressure of the nitrogen gas after pressure adjustment to within the required operating pressure range.

[0131] The pressure-increasing flow path 80b is provided with, in this order from upstream, a pressure-increasing solenoid valve 83b, a pressure-increasing valve (regulator) 82b, and a check valve CV2. A known pressure-increasing valve 82b is used as the pressure adjusting unit 82, and increases the pressure of nitrogen gas that is below the lower limit of the required operating pressure, and adjusts the pressure of the nitrogen gas after pressure adjustment to within the range of the required operating pressure.

[0132] The flow path 80c for when pressure regulation is not required is provided with an electromagnetic valve 83c for when pressure regulation is not required and a check valve CV3 in this order from upstream.

[0133] The pressure reducing flow path 80a, the pressure increasing flow path 80b, and the pressure adjusting unnecessary flow path 80c join together in the nitrogen gas supply flow path 30 on the secondary side of each of the check valves CV1, CV2, and CV3.

[0134] Each check valve CV1, CV2, and CV3 prevents nitrogen gas after pressure adjustment or nitrogen gas that has passed through the flow path 80c for when pressure adjustment is not required from flowing back through the flow path 80a for when pressure is reduced, the flow path 80b for when pressure is increased, and the flow path 80c for when pressure adjustment is not required.

[0135] Furthermore, even after the purging process of releasing the compressed air in the air tank 3 is performed by each check valve CV1, CV2, and CV3, the nitrogen gas pressure (PV control pressure) will remain in the nitrogen gas supply passage 30 on the secondary side of each check valve CV1, CV2, and CV3.

[0136] As a result, the next time the engine-driven compressor 1 is started, the gas fuel supply control solenoid valve 43 is controlled to connect the nitrogen gas supply passage 30 to the gas fuel supply valve control circuit 42, and the remaining nitrogen gas (operating pressure) described above is introduced into the gas fuel supply valve 41 to open the gas fuel supply valve 41, thereby starting the introduction of gas fuel (hydrogen gas) into the fuel supply passage 22 and making it possible to supply the gas fuel to the engine 13.

[0137] In addition, the pressure regulating mechanism 80 is equipped with an air tank pressure sensor 85 that detects the pressure in the air tank 3 and transmits a detection signal to the control device 70, and is also equipped with a purified nitrogen gas pressure sensor 86 that is arranged on the secondary side of the nitrogen gas purification device 32 and detects the pressure of the nitrogen gas immediately after purification and transmits a detection signal to the control device 70.

[0138] Furthermore, in this embodiment, a pressure sensor 90 is provided on the secondary side of the check valves (CV1, CV2, CV3) to detect the pressure (PV control pressure) in the nitrogen gas supply flow path 30 and transmit a detection signal to the control device 70. In this embodiment, the pressure sensor 90 is provided on the secondary side of the confluence of the flow path for pressure reduction 80a, the flow path for pressure increase 80b, and the flow path for when pressure adjustment is not required 80c. However, in the present invention, which has a configuration in which the above-mentioned flow path for pressure reduction 80a, the flow path for pressure increase 80b, and the flow path for when pressure adjustment is not required 80c converge on the secondary side of each check valve CV1, CV2, CV3 within the nitrogen gas supply flow path 30, there is no difference in the measurement results as long as the pressure sensor 90 is provided within the nitrogen gas supply flow path 30 on the secondary side of any of the check valves CV1, CV2, CV3. Therefore, for example, the pressure sensor 90 may be provided on the secondary side of any of the check valves CV1, CV2, CV3 before the confluence of the flow path for pressure reduction 80a, the flow path for pressure increase 80b, and the flow path for when pressure adjustment is not required 80c, and the arrangement of the pressure sensor 90 is not limited to the example of Figure 4.

[0139] (2) Control device 70 In the control device 70 of this embodiment, the operation of the above-mentioned pressure adjustment mechanism 80 is controlled by executing a pre-stored program to realize the pressure adjustment control means 76 added in this embodiment, which is shown in the functional block diagram of Figure 5.

[0140] In addition, in this embodiment, the pressure adjustment control means 76 realized in the control device 70 electrically controls the operation of the pressure adjustment control solenoid valves 83 (solenoid valve 83a for pressure reduction, solenoid valve 83b for pressure increase, solenoid valve 83c for when pressure adjustment is not required) provided in the above-mentioned pressure adjustment mechanism 80, thereby performing the following nitrogen gas pressure adjustment process.

[0141] Pressure regulation control means 76 (nitrogen gas pressure regulation process) After the engine-driven compressor 1 starts, the control device 70 activates the pressure regulation control means 76 .

[0142] The pressure adjustment control means 76 controls the operation of the pressure adjustment mechanism 80 to perform nitrogen gas pressure adjustment processing to keep constant the pressure of the nitrogen gas in the nitrogen gas supply flow path 30 supplied to the gaseous fuel supply valve 41, which is an air valve, and the air release valve 51 (51a, 51b), within the range of required operating pressure. In this embodiment, as described above, the gaseous fuel supply valve 41 and the air release valve 51 (51a, 51b) have upper and lower limit values ​​set for the required operating pressure.

[0143] When the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor 86 exceeds the upper limit of the required operating pressure for the gas fuel supply valve 41a and the air release valve 51 (51a, 51b), the pressure adjustment control means 76 opens the pressure reduction solenoid valve 80a, while closing the pressure increase solenoid valve 80b and the pressure adjustment no-required solenoid valve 83c.

[0144] As a result, the nitrogen gas purified by the nitrogen gas purification device 32 passes through the pressure reducing flow path 80a, and the pressure of the nitrogen gas is reduced by the pressure reducing valve 82a to adjust the pressure within the required operating pressure range.

[0145] In addition, when the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor 86 falls below the lower limit of the required operating pressure for the gas fuel supply valve 41 and the air release valve 51 (51a, 51b), the pressure adjustment control means 76 opens the pressure increase solenoid valve 80b, while closing the pressure reduction solenoid valve 80a and the pressure no adjustment required solenoid valve 83c.

[0146] As a result, the nitrogen gas purified by the nitrogen gas purification device 32 passes through the pressure-increasing flow path 80b, and the pressure of the nitrogen gas is increased by the pressure-increasing valve 82b and adjusted to within the required operating pressure range.

[0147] Furthermore, when the nitrogen gas pressure immediately after purification detected by the purified nitrogen gas pressure sensor 86 is within the range of the required operating pressure for the gas fuel supply valve 41 and the air release valve 51 (51a, 51b), the solenoid valve 83c for when pressure adjustment is not required is opened, while the solenoid valve 80a for when pressure is reduced and the solenoid valve 80b for when pressure is increased are closed.

[0148] As a result, the nitrogen gas purified by the nitrogen gas purification device 32 passes through the flow path 80c for when pressure adjustment is not required.

[0149] (3) Operation, etc. The operation of the engine-driven compressor 1 having the residual gaseous fuel discharge device 12 equipped with the pressure regulation mechanism 80 and the pressure regulation control means 76 configured as above will be described with reference to FIG.

[0150] When the operator turns on the main switch of the engine-driven compressor 1, electricity is supplied to each part of the engine-driven compressor 1, and the control device 70 starts up.

[0151] Then, when the operator turns the start switch to "ON", the control device 70 starts the engine 13 and controls the gas fuel supply control solenoid valve 43 to introduce nitrogen gas (operating pressure) into the gas fuel supply valve 41 to open the gas fuel supply valve 41 in order to supply hydrogen gas to the engine 13, thereby starting the introduction of gas fuel into the fuel supply path 22 (22a, 22b) (T1 in the figure).

[0152] At this time, the nitrogen gas (operating pressure) remaining on the secondary side of the check valves CV1, CV2, and CV3 is introduced into the gas fuel supply valve 41, causing the PV control pressure to drop slightly (T2 in the figure), but since nitrogen gas is constantly supplied via either the pressure reduction solenoid valve 83a, the pressure increase solenoid valve 83b, or the pressure adjustment not required solenoid valve 83c while the engine-driven compressor 1 is operating after the engine 13 starts, the PV control pressure quickly recovers.

[0153] Also, immediately after starting the engine 13, the pressure in the air tank 3 and the pressure of the nitrogen gas refined by the nitrogen gas refiner 32 are below the lower limit of the required operating pressure, so the pressure adjustment control means 76 opens the pressure increase solenoid valve 83b, while closing the pressure reduction solenoid valve 83a and the pressure adjustment not required solenoid valve 83c, and increases the pressure of the nitrogen gas refined by the nitrogen gas refiner 32 by passing it through the pressure increase flow path 80b (T1 in the figure).

[0154] After the engine 13 starts and during no-load operation (when compressed air is not being used by pneumatic work machines or the like connected to the service valve 5), as the rotation speed of the engine 13 increases, the amount of compressed air produced increases, and the pressure in the air tank 3 and the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 increase, and when the pressure of the nitrogen gas exceeds the lower limit of the required operating pressure, the pressure adjustment control means 76 opens the solenoid valve 83c for when pressure adjustment is not required, while closing the solenoid valve 83a for when pressure is reduced and the solenoid valve 83b for when pressure is increased, and causes the nitrogen gas purified by the nitrogen gas purification device 32 to pass through the flow path 80c for when pressure adjustment is not required (T2 in the figure).

[0155] Furthermore, during no-load operation, the amount of compressed air produced increases, and the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 rises along with the pressure in the air tank 3. When the pressure of the nitrogen gas exceeds the upper limit of the required operating pressure, the pressure adjustment control means 76 opens the pressure reduction solenoid valve 83a, while closing the pressure increase solenoid valve 83b and the pressure adjustment not required solenoid valve 83c, and reduces the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 through the pressure reduction flow path 80a (T3 in the figure).

[0156] After a while of transitioning from no-load operation to full-load operation (T4 in the figure), the pressure of the nitrogen gas refined by the nitrogen gas refiner 32 decreases along with the pressure inside the air tank 3, and when the pressure of the nitrogen gas falls below the upper limit of the required operating pressure, the pressure adjustment control means 76 opens the solenoid valve 83c for when pressure adjustment is not required, while closing the solenoid valve 83a for when pressure is reduced and the solenoid valve 83b for when pressure is increased, and causes the nitrogen gas refined by the nitrogen gas refiner 32 to pass through the flow path 80c for when pressure adjustment is not required (T5 in the figure).

[0157] Furthermore, due to an increase in the consumption of compressed air (T6 in the figure), after a while, the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 decreases along with the pressure in the air tank 3, and when the pressure of the nitrogen gas falls below the lower limit of the required operating pressure, the pressure adjustment control means 76 opens the pressure increase solenoid valve 83b, while closing the pressure reduction solenoid valve 83a and the pressure adjustment not required solenoid valve 83c, and increases the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 by passing it through the pressure increase flow path 80b (T7 in the figure).

[0158] The consumption of compressed air begins to decrease (T8 in the figure), and after a while, the pressure of the nitrogen gas refined by the nitrogen gas refiner 32 increases along with the pressure inside the air tank 3, and when the pressure of the nitrogen gas exceeds the lower limit of the required operating pressure, the pressure adjustment control means 76 opens the solenoid valve 83c for when pressure adjustment is not required, and closes the solenoid valve 83a for when pressure is reduced and the solenoid valve 83b for when pressure is increased, so that the nitrogen gas refined by the nitrogen gas refiner 32 passes through the flow path 80c for when pressure adjustment is not required (T9 in the figure).

[0159] At the end of full load operation (T10 in the figure), the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 is still within the required operating pressure range, so the pressure adjustment control means 76 opens the solenoid valve 83c for when pressure adjustment is not required, while closing the solenoid valve 83a for when pressure is reduced and the solenoid valve 83b for when pressure is increased, and causes the nitrogen gas purified by the nitrogen gas purification device 32 to pass through the flow path 80c for when pressure adjustment is not required (T10 in the figure).

[0160] After the full load operation is completed, the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 increases together with the pressure in the air tank 3, and when the pressure of the nitrogen gas exceeds the upper limit of the required operating pressure, the pressure adjustment control means 76 opens the pressure reduction solenoid valve 83a, while closing the pressure increase solenoid valve 83b and the pressure adjustment unnecessary solenoid valve 83c, and reduces the pressure of the nitrogen gas purified by the nitrogen gas purification device 32 through the pressure reduction flow path 80a (T11 in the figure).

[0161] Then, for example, after the operation stop switch is operated by an operator, if the stop condition determination means 71 determines that the stop condition has been met, the engine stop control means 72 outputs a stop command for the engine 13 to the ECU 14 of the engine 13 to execute the stop process for the engine 13, and the gas fuel supply stop control means 74 closes the gas fuel supply control solenoid valve 43 to stop the introduction of nitrogen gas (operating pressure) into the gas fuel supply valve 41 and closes the gas fuel supply valve 41, thereby stopping the introduction of gas fuel into the fuel supply path 22 (T12 in the figure).

[0162] At the same time, the fuel supply path fuel discharge control means 75 opens the air release valve control solenoid valves 53 (53a, 53b) to start introducing nitrogen gas (at operating pressure) into the air release valves 51 (51a, 51b) and opens the air release valves 51 (51a, 51b), thereby opening the fuel supply paths 22 (22a, 22b) to the atmosphere via the air release flow paths 54 (54a, 54b) (T12 in the figure). In this way, with the supply of hydrogen gas to the fuel supply paths 22 (22a, 22b) stopped and the fuel supply paths 22 (22a, 22b) being opened to the atmosphere via the air release flow paths 54 (54a, 54b), the hydrogen gas remaining in the fuel supply paths 22 (22a, 22b) is released to the atmosphere.

[0163] In addition, in order to open the air release valve 51 (51a, 51b), nitrogen gas is introduced into the air release valve (51a, 51b), which causes the PV control pressure to decrease slightly. However, during this time, the pressure reducing solenoid valve 83a remains open, so nitrogen gas continues to be supplied and the PV control pressure recovers.

[0164] Then, when the release of hydrogen gas to the atmosphere from the fuel supply path 22 (22a, 22b) is completed (for example, the aforementioned timer provided in the control device 70 continues counting from the start of the release of hydrogen gas to the atmosphere until a predetermined discharge time t2 has elapsed, and after the predetermined discharge time t2 has been counted), the fuel supply path fuel discharge control means 75 starts nitrogen replacement to introduce nitrogen gas into the fuel supply path 22 (22a, 22b) by opening the nitrogen gas introduction control solenoid valve 61 while keeping the air release valve 51 (51a, 51b) open (T13 in the figure). During nitrogen replacement, the PV control pressure decreases to introduce nitrogen gas into the fuel supply path 22 (22a, 22b), but during this time the pressure reduction solenoid valve 83a remains open and nitrogen gas continues to be supplied.

[0165] When the nitrogen replacement in the fuel supply path 22 (22a, 22b) is completed (for example, the aforementioned timer provided in the control device 70 continues counting from the start of nitrogen gas introduction until a predetermined introduction time t3 has elapsed, and after the predetermined introduction time t3 has elapsed), the fuel supply path fuel discharge control means 75 ends the fuel supply path fuel discharge process (T14 in the figure).

[0166] This fuel discharge process within the fuel supply path is terminated by the fuel supply path fuel discharge control means 75 closing the air release valve control solenoid valve 53 (53a, 53b) and closing the air release valve 51 (51a, 51b), thereby terminating the opening of the fuel supply path 22 (22a, 22b) to the atmosphere, and by closing the nitrogen gas introduction control solenoid valve 61 to stop the introduction of nitrogen gas into the fuel supply path 22 (22a, 22b) (T14 in the figure).

[0167] Furthermore, after the fuel discharge process in the fuel supply line is completed, when the pressure sensor 90 detects that the PV control pressure has recovered, the pressure adjustment control means 76 closes all of the solenoid valve 83a for pressure reduction, the solenoid valve 83b for pressure increase, and the solenoid valve 83c for when pressure adjustment is not required, thereby ending the nitrogen gas pressure adjustment process, and the purge control means 78 opens the purge valve 6 and performs a purge process to release the compressed air in the air tank 3 (T15 in the figure).

[0168] This completes the process of discharging the remaining gaseous fuel.

[0169] Furthermore, after the completion of the above-mentioned residual gaseous fuel discharge process and the completion of the purging process, the pressure of the nitrogen gas (PV control pressure) in the nitrogen gas supply passage 30 on the secondary side of each check valve CV1, CV2, CV3 remains, so that the next time the engine-driven compressor 1 is started, the remaining nitrogen gas can open the gaseous fuel supply valve 41, allowing hydrogen gas to be supplied to the engine 13.

[0170] 4, the pressure regulating mechanism 80 is disposed on the secondary side of the nitrogen gas purifier 32, but if the pressure of the nitrogen gas purified by the nitrogen gas purifier 32 is the same as the pressure of the compressed air introduced into the nitrogen gas purifier 32, the pressure regulating mechanism 80 may be disposed on the primary side of the nitrogen gas purifier 32. In this case, the pressure regulation control means 76 controls to open one of the pressure reducing solenoid valve 83a, the pressure increasing solenoid valve 83b, and the pressure regulation not required solenoid valve 83c and close the remaining two, as described above, depending on whether the pressure of the compressed air in the air tank 3 detected by the air tank pressure sensor 85 is within the range of the required operating pressure for the gaseous fuel supply valve 41 and the air release valve 51 (51a, 51b), is below the lower limit of the required operating pressure, or is above the upper limit of the required operating pressure.

[0171] [Modification 2 of the Residual Gaseous Fuel Discharge Device] (Embodiment 3) Next, another embodiment (Embodiment 3) of the engine-driven compressor 1 will be described, but the configuration of the engine-driven compressor 1 in this embodiment is the same as that of Embodiment 1 described with reference to Figures 1 to 3 and that of Embodiment 2 described with reference to Figures 4 to 6, except for the configuration described below, and therefore description thereof will be omitted. Furthermore, parts corresponding to those in Embodiments 1 and 2 will be described using the same reference numerals.

[0172] In this embodiment shown in FIG. 7, the gas fuel supply valve 41 and the air release valve 51 (51a, 51b) which are air operated valves have only a lower limit value of the required operating pressure.

[0173] The pressure adjustment mechanism 80 shown in Figure 7 is provided with a pressure adjustment section 82 that is arranged in the nitrogen gas supply flow path 30 and adjusts the pressure of the nitrogen gas passing through it to within the required operating pressure range, and a check valve CV is arranged on the secondary side of the pressure adjustment section 82.

[0174] In this embodiment, a known pressure booster valve is used as the pressure regulating unit 82, and the pressure of the nitrogen gas in the nitrogen gas supply passage 30 is kept constant by the pressure regulating unit (pressure booster valve) 82 at or above the lower limit of the required operating pressure so that it does not fall below the lower limit of the required operating pressure for the gas fuel supply valve 41 and the air release valve 51 (51a, 51b).

[0175] In the illustrated example, the above-mentioned pressure regulating mechanism 80 (pressure regulating section 82) is arranged on the secondary side of the nitrogen gas purifying device 32, but if the pressure of the nitrogen gas purified by the nitrogen gas purifying device 32 is the same as the pressure of the compressed air introduced into the nitrogen gas purifying device 32, the pressure regulating mechanism 80 may also be arranged on the primary side of the nitrogen gas purifying device.

[0176] In addition, the check valve CV prevents the nitrogen gas from flowing back after pressure adjustment, and even after the compressed air in the air tank 3 is released (purging process) upon completion of the discharge process of the residual gaseous fuel, the nitrogen gas pressure (PV control pressure) remains in the nitrogen gas supply passage 30 on the secondary side of the check valve CV.

[0177] In the pressure regulating mechanism 80 of this embodiment described above, unlike the previously described embodiment 2, there is no need to branch the nitrogen gas supply flow path 30 into multiple flow paths along the way, and furthermore, the solenoid valve can be omitted and there is no need to control the solenoid valve using the control device 70, thereby simplifying the device configuration.

[0178] In this embodiment and the above-mentioned embodiment 2, a pressure reducing valve or a pressure increasing valve is used as the pressure adjusting section 82 that adjusts the pressure of the nitrogen gas in the nitrogen gas supply flow path 30, but in the present invention, other pressure adjusting devices or pressure adjusting means can be used as the pressure adjusting section 82 as long as they can adjust the pressure of the nitrogen gas in the flow path. [Explanation of symbols]

[0179] 1. Engine-driven compressor 2 Compressor body 3. Air tank 4 intake valves 5 Service valve 6 Purge valve 10 Gaseous fuel engine unit (hydrogen engine unit) 12 Residual gaseous fuel exhaust device 13 Engine 14 Engine Control Unit (ECU) 20 Gaseous fuel source (hydrogen source) 22 Fuel supply line (hydrogen gas supply line) 22a Primary side fuel supply path 22b Secondary fuel supply path 24 Pressure regulator (for gaseous fuel) 30 Nitrogen gas supply channel 32 Nitrogen gas purification equipment 40 Gaseous fuel supply control mechanism 41 Gaseous fuel supply valve (air valve) 42 Gaseous fuel supply valve control circuit 43 Gaseous fuel supply control solenoid valve 50 Air release mechanism 50a Primary side air release mechanism 50b Secondary air release mechanism 51 Air release valve (air valve) 51a Primary side air release valve 51b Secondary side air release valve 52 Air release valve control circuit 52a Primary side air release valve control circuit 52b Secondary side air release valve control circuit 53 Solenoid valve for controlling air release valve 53a Primary side air release valve control solenoid valve 53b Secondary side air release valve control solenoid valve 54(54a,54b) Air discharge channel 60 Nitrogen gas introduction control mechanism 61 Nitrogen gas introduction control solenoid valve 62 Nitrogen gas inlet channel 70 Control device 71 Stop condition determination means 72 Engine stop control means 74 Gaseous fuel supply stop control means 75 Fuel discharge control means in fuel supply path 76 Pressure regulation control means 78 Purge control means 80 Pressure Regulating Mechanism 80a Pressure reduction flow path 80b Pressure increase flow path 80c Flow path when pressure regulation is not required 82 Pressure adjustment section 82a Pressure reducing valve 82b Pressure booster valve 83 Pressure regulation solenoid valve 83a Pressure reducing solenoid valve 83b Pressure boost solenoid valve 83c Solenoid valve for when pressure regulation is not required 85 Air tank pressure sensor 86 Purified nitrogen gas pressure sensor 90 Pressure Sensor CV (CV1, CV2, CV3) check valve cv1, cv2, cv3 check valves 100 Gaseous fuel engine unit (hydrogen engine unit) 102 Residual gas fuel exhaust device 110 Engine 111 Engine Control Unit (ECU) 112 Starter motor 120 Hydrogen Cylinder (Gaseous Fuel Source) 122 Fuel supply line (hydrogen gas supply line) 122a Primary side fuel supply path 122b Secondary fuel supply path 124 Pressure regulator (for gaseous fuel) 130 Nitrogen gas supply unit 131 Nitrogen Cylinder 132 Nitrogen gas supply line 133 Nitrogen gas pressure regulator 140 Gaseous fuel supply control mechanism 141 Gaseous fuel supply valve 142 Gaseous fuel supply valve control circuit 143 Gaseous fuel supply control solenoid valve 150 Air release mechanism 150a Primary side air release mechanism 150b Secondary air release mechanism 151 Air release valve 151a Primary side air release valve 151b Secondary side air release valve 152 Air release valve control circuit 152a Primary side air release valve control circuit 152b Secondary side air release valve control circuit 153 Solenoid valve for controlling air release valve 153a Primary side air release valve control solenoid valve 153b Secondary side air release valve control solenoid valve 154(154a,154b) Air discharge channel 160 Nitrogen gas introduction control mechanism 161 Nitrogen gas introduction control solenoid valve 162 Nitrogen gas inlet channel 170 Control device (electronic control device) cv1', cv2', cv3' check valves

Claims

1. a compressor body that sucks in and compresses a fluid to be compressed; a gaseous fuel engine unit configured with an engine capable of using gaseous fuel as fuel and driving the compressor body, and a fuel supply passage for supplying gaseous fuel from a gaseous fuel source to the engine; an air tank for storing compressed gas discharged from the compressor body, The gaseous fuel engine unit comprises: a nitrogen gas supply flow path that is connected to the air tank and that allows nitrogen gas purified from compressed air from the air tank by a nitrogen gas purification device provided in the flow path to be introduced into the fuel supply path; a gaseous fuel supply control mechanism that opens and closes between the gaseous fuel source and the fuel supply path; an air release mechanism that starts and stops opening the fuel supply passage to the atmosphere; a nitrogen gas introduction control mechanism that opens and closes the nitrogen gas supply passage and the fuel supply passage; a residual gaseous fuel discharge device configured by a control device including an electronic control device that controls operations of the gaseous fuel supply control mechanism, the air release mechanism, and the nitrogen gas introduction control mechanism, The residual gas fuel discharge device is configured by the control device. a gaseous fuel supply stop control means that, when stopping the engine, operates the gaseous fuel supply control mechanism to cut off communication between the gaseous fuel source and the fuel supply path, thereby executing a gaseous fuel supply stop process to stop the supply of gaseous fuel to the fuel supply path; and a fuel supply passage fuel discharge control means for performing a fuel supply passage fuel discharge process for discharging the gaseous fuel remaining in the fuel supply passage into the atmosphere after the gaseous fuel supply stop control means executes the gaseous fuel supply stop process; The fuel discharge control means in the fuel supply path A residual gaseous fuel discharge device in an engine-driven compressor equipped with a gaseous fuel engine unit, characterized in that the device is configured to operate the air release mechanism to open the fuel supply path to the atmosphere, and while open to the atmosphere, operate the nitrogen gas introduction control mechanism to introduce nitrogen gas from the nitrogen gas supply flow path into the fuel supply path, thereby performing a fuel discharge process within the fuel supply path.

2. The engine-driven compressor includes a purge valve that can release the compressed air stored in the air tank to the atmosphere, and the nitrogen gas supply passage is provided with a check valve on the secondary side of the nitrogen gas purifier; the gaseous fuel supply control mechanism comprises a gaseous fuel supply valve which is an air-operated valve and opens and closes between the gaseous fuel source and the fuel supply path, a gaseous fuel supply valve control circuit which introduces nitrogen gas from the nitrogen gas supply path into the gaseous fuel supply valve as an operating pressure, and a gaseous fuel supply control electromagnetic valve which establishes and cuts communication between the nitrogen gas supply path and the gaseous fuel supply valve control circuit, the air release mechanism is composed of an air release valve which is an air-operated valve and which opens the fuel supply passage to the atmosphere, an air release valve control circuit which introduces nitrogen gas from the nitrogen gas supply passage into the air release valve as an operating pressure, and an air release valve control solenoid valve which establishes and blocks communication between the nitrogen gas supply passage and the air release valve control circuit, the nitrogen gas introduction control mechanism is composed of a nitrogen gas introduction flow path that communicates between the nitrogen gas supply flow path and the fuel supply path, and a nitrogen gas introduction control electromagnetic valve that is provided between the nitrogen gas introduction flow path and the nitrogen gas supply flow path, The gas fuel supply control solenoid valve is configured to be operable by the gas fuel supply stop control means of the control device, 2. A residual gas fuel discharge device in an engine-driven compressor equipped with a gas fuel engine unit according to claim 1, wherein the air release valve control solenoid valve and the nitrogen gas introduction control solenoid valve are configured to be operable by the fuel discharge control means in the fuel supply passage of the control device.

3. 3. A residual gaseous fuel discharge device in an engine-driven compressor equipped with a gaseous fuel engine unit as described in claim 2, characterized in that the nitrogen gas supply passage is provided with a pressure regulating unit that regulates the pressure of the nitrogen gas supplied from the nitrogen gas supply passage to within a range of operating pressure required to operate the gaseous fuel supply valve and the air release valve, and a pressure regulating mechanism is provided in which the check valve is arranged on the secondary side of the pressure regulating unit.

4. The pressure regulating mechanism branches the nitrogen gas supply flow path into three flow paths, and is composed of a flow path for pressure reduction which is provided with a pressure reducing valve as the pressure regulating section and the check valve is arranged on the secondary side of the pressure reducing valve, a flow path for pressure increase which is provided with a pressure increasing valve as the pressure regulating section and the check valve is arranged on the secondary side of the pressure increasing valve, and a flow path for when pressure regulation is not required which does not have the pressure regulating section and is arranged with the check valve, and the flow path for pressure reduction which is provided with the pressure increasing flow path and the flow path for when pressure regulation is not required are joined on the secondary side of each check valve within the nitrogen gas supply flow path, and the pressure regulating mechanism includes a purified nitrogen gas pressure sensor disposed on the secondary side of the nitrogen gas purifier, which detects the pressure of the nitrogen gas immediately after purification and transmits a detection signal to a control device; By the control device, When the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor exceeds the upper limit value of the required operating pressure, the pressure regulating mechanism is operated to cause the nitrogen gas purified by the nitrogen gas purifier to pass through the pressure reducing flow path, and the pressure of the nitrogen gas is reduced by the pressure reducing valve to regulate the pressure within the required operating pressure range, When the pressure of the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor falls below the lower limit of the required operating pressure, the pressure regulating mechanism is operated to cause the nitrogen gas purified by the nitrogen gas purification device to pass through the pressure-increasing flow path, and the pressure of the nitrogen gas is increased by the pressure-increasing valve to adjust the pressure within the required operating pressure range, 4. A residual gaseous fuel discharge device in an engine-driven compressor equipped with a gaseous fuel engine unit as described in claim 3, characterized in that the device is configured to realize a pressure adjustment control means that, when the nitrogen gas immediately after purification detected by the purified nitrogen gas pressure sensor is within the required operating pressure range, operates the pressure adjustment mechanism to perform a nitrogen gas pressure adjustment process by causing the nitrogen gas purified by the nitrogen gas purification device to pass through the flow path for when pressure adjustment is not required.

5. a pressure reducing solenoid valve on the primary side of the pressure reducing valve in the pressure reducing flow path, a pressure increasing solenoid valve on the primary side of the pressure increasing valve in the pressure increasing flow path, and a pressure adjustment not required solenoid valve on the primary side of the check valve in the pressure adjustment not required flow path, 5. A residual gas fuel discharge device in an engine-driven compressor equipped with a gas fuel engine unit as claimed in claim 4, characterized in that the pressure reduction solenoid valve, the pressure increase solenoid valve, and the pressure regulation non-requiring solenoid valve are configured to be operable by the pressure regulation control means.

6. The purge valve is configured as an electromagnetic valve and is operable by the control device, A residual gaseous fuel discharge device in an engine-driven compressor equipped with a gaseous fuel engine unit as described in any one of claims 2 to 5, characterized in that the control device realizes a purge control means that opens the purge valve to perform a purge process to release the compressed gas in the air tank.

7. A pressure sensor is provided on the secondary side of the check valve to detect the pressure of the nitrogen gas in the nitrogen gas supply flow path as a PV control pressure and transmit a detection signal to the control device; 7. A residual gaseous fuel discharge device in an engine-driven compressor equipped with a gaseous fuel engine unit as described in claim 6, wherein the purge control means opens the purge valve and executes the purge process when the pressure sensor detects that the PV control pressure has recovered after the PV control pressure has decreased by introducing nitrogen gas into the fuel supply line during the fuel discharge process within the fuel supply line, and nitrogen gas is supplied from the air tank via the nitrogen gas purification device.

8. An engine-driven compressor including a compressor main body that sucks in and compresses a fluid to be compressed, an engine that can use gaseous fuel as fuel and drives the compressor main body, and a gaseous fuel engine unit that includes a fuel supply path that supplies gaseous fuel from a gaseous fuel source to the engine, and an air tank that stores compressed gas discharged from the compressor main body, a nitrogen gas supply flow path in the gaseous fuel engine unit, the nitrogen gas supply flow path being connected to the air tank and configured to introduce nitrogen gas purified from compressed air from the air tank by a nitrogen gas purification device provided midway through the flow path into the fuel supply path; a gaseous fuel supply stop process for stopping the supply of gaseous fuel from the gaseous fuel source to the fuel supply passage when the engine is stopped; After the gaseous fuel supply stop processing, a fuel discharge processing is performed in the fuel supply path to discharge the gaseous fuel remaining in the fuel supply path to the atmosphere. A method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit, characterized in that the fuel discharge process within the fuel supply passage is carried out by introducing nitrogen gas into the fuel supply passage through the nitrogen gas supply passage while the fuel supply passage is open to the atmosphere, thereby pushing out the gaseous fuel remaining in the fuel supply passage and replacing it with the nitrogen gas.

9. the engine-driven compressor is provided with a purge valve capable of releasing the compressed air stored in the air tank to the atmosphere, The gaseous fuel engine unit includes a gaseous fuel supply valve and an air release valve, each of which is an air-operated valve; the nitrogen gas supply passage is provided with a check valve on the secondary side of a nitrogen gas purification device, and is capable of supplying nitrogen gas as an operating pressure to the gaseous fuel supply valve and the air release valve; The gaseous fuel supply stopping process stops the supply of gaseous fuel from the gaseous fuel source to the fuel supply path by stopping the introduction of nitrogen gas from the nitrogen gas supply passage to the gaseous fuel supply valve and closing the gaseous fuel supply valve, and 9. The method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit according to claim 8, wherein the process of discharging fuel in the fuel supply passage comprises starting the introduction of nitrogen gas from the nitrogen gas supply passage to the air release valve and opening the air release valve to release the gaseous fuel remaining in the fuel supply passage into the atmosphere.

10. 10. The method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit according to claim 9, further comprising a nitrogen gas pressure adjustment process for adjusting the pressure of the nitrogen gas supplied from the nitrogen gas supply passage to within a range of operating pressure required for operating the gaseous fuel supply valve and the air release valve.

11. Detecting the pressure of the nitrogen gas immediately after purification on the secondary side of the nitrogen gas purification device, The nitrogen gas supply flow path is branched into three flow paths, forming a flow path for when pressure is reduced which is equipped with a pressure reducing valve and the check valve is disposed on the secondary side of the pressure reducing valve, a flow path for when pressure is increased which is equipped with a pressure increasing valve and the check valve is disposed on the secondary side of the pressure increasing valve, and a flow path for when pressure adjustment is not required which does not have a pressure adjustment unit for adjusting the pressure of the nitrogen gas and in which the check valve is disposed within the flow path, and the flow path for when pressure reduction is required, the flow path for when pressure increase is required, and the flow path for when pressure adjustment is not required are merged on the secondary side of each check valve within the nitrogen gas supply flow path, The nitrogen gas pressure adjustment process is When the detected pressure of the nitrogen gas immediately after purification exceeds an upper limit of the required operating pressure, the nitrogen gas purified by the nitrogen gas purification device is passed through the pressure reducing flow path, and the pressure of the nitrogen gas is reduced by the pressure reducing valve to adjust the pressure within the required operating pressure range; When the detected pressure of the nitrogen gas immediately after purification falls below the lower limit of the required operating pressure, the nitrogen gas purified by the nitrogen gas purification device is passed through the pressure-increasing flow path, and the pressure of the nitrogen gas is increased by the pressure-increasing valve to adjust the pressure to within the required operating pressure range; A method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit as described in claim 10, characterized in that, when the detected pressure of the nitrogen gas immediately after purification is within the required operating pressure range, the nitrogen gas purified by the nitrogen gas purification device is passed through the flow path for when pressure adjustment is not required.

12. a pressure reducing solenoid valve on the primary side of the pressure reducing valve in the pressure reducing flow path, a pressure increasing solenoid valve on the primary side of the pressure increasing valve in the pressure increasing flow path, and a pressure adjustment not required solenoid valve on the primary side of the check valve in the pressure adjustment not required flow path, A method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit as described in claim 11, characterized in that the nitrogen gas purified by the nitrogen gas purification device is passed through any of the pressure reduction flow path, the pressure increase flow path, and the pressure adjustment non-requiring flow path by operating the pressure reduction solenoid valve, the pressure increase solenoid valve, and the pressure adjustment non-requiring solenoid valve.

13. A method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit according to any one of claims 9 to 12, comprising a purging process of opening the purge valve to release the compressed gas in the air tank.

14. The pressure of the nitrogen gas in the nitrogen gas supply passage on the secondary side of the check valve is detected as a PV control pressure, 14. The method for discharging residual gaseous fuel in an engine-driven compressor equipped with a gaseous fuel engine unit according to claim 13, wherein the purging process comprises: introducing nitrogen gas into the fuel supply line during a process for discharging fuel from the fuel supply line, thereby reducing the PV control pressure; supplying nitrogen gas from the air tank via the nitrogen gas purifier; and opening the purge valve when recovery of the PV control pressure is detected.

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