Fuel supply system

Abstract

This fuel supply system comprises: a fuel supply tank which holds liquefied hydrogen; a fuel pump which is disposed on a fuel supply flow path; a branch flow path; a gas-liquid separator which is installed on the branch flow path; a gas reservoir into which hydrogen gas which has been separated off in the gas-liquid separator is introduced and temporarily stored, and which supplies the hydrogen gas to a predetermined device which uses the hydrogen gas as fuel; a first control valve which is disposed on the fuel supply flow path; a second control valve which is disposed on the branch flow path; and a controller. At engine startup time, the controller opens the first control valve while in a state where the second control valve is closed, initiates driving of the fuel pump. At engine shutdown time, the controller closes the first control valve, halts driving of the fuel pump, and temporarily opens the second control valve.

Description

Fuel supply system

[0001] The present disclosure relates to a fuel supply system for an engine using hydrogen as fuel.

[0002] For example, an engine using hydrogen as fuel is known in ships and the like. Patent Document 1 discloses a fuel supply system for a liquefied gas carrier. This fuel supply system includes a fuel supply line that supplies liquefied gas from a fuel supply tank to an in-ship engine, and a return line that recirculates the liquefied gas remaining unused in the in-ship engine upstream of the in-ship engine. And, a transfer pump for transporting the liquefied gas and a pressurizing pump for pressurizing the liquefied gas to the pressure required by the in-ship engine are provided in the fuel supply line. Further, a separator for gas-liquid separation of the liquefied gas is provided in the return line. And, the fuel supply system further includes a liquid line that supplies the liquid liquefied gas separated by the separator downstream of the transfer pump in the fuel supply line. Also, the fuel supply system includes a vapor line that recovers the gas separated by the separator to the fuel supply tank.

[0003] Japanese Patent Publication No. 2023-538058

[0004] In the configuration of Patent Document 1 above, by returning the liquid liquefied gas separated by the separator to the fuel supply line through the liquid line and recovering the gas separated by the separator to the fuel supply tank, waste of fuel is prevented and effective utilization of fuel is achieved.

[0005] In the configuration of this Patent Document 1, the gas separated by the separator is recovered to the fuel supply tank. Further, a re-liquefaction unit for re-liquefying the evaporated gas generated in the cargo tank for storing the liquefied gas transported to the ship is provided in the ship. And, by providing a cooling line that returns the liquefied gas re-liquefied by the re-liquefaction unit to the cargo tank via the inside of the fuel supply tank, an increase in the pressure inside the fuel supply tank and the like is suppressed.

[0006] However, for example, if the liquefied gas stored in the fuel supply tank is liquefied hydrogen, its volume increases by approximately 800 times when it turns into a gas. Therefore, in a configuration where the hydrogen gas separated by the separator is constantly recovered into the fuel supply tank, there is a concern that the pressure inside the fuel supply tank will rise.

[0007] This disclosure was made to solve the above-mentioned problems and aims to provide a fuel supply system that can effectively utilize the fuel used in hydrogen-powered engines and minimize the rise in pressure inside the fuel supply tank.

[0008] To achieve the above objective, a fuel supply system according to one aspect of the present disclosure includes: a fuel supply tank for storing liquefied hydrogen; a fuel pump located in a fuel supply channel that supplies the liquefied hydrogen from the fuel supply tank to an engine as hydrogen fuel, which pressurizes the hydrogen fuel and sends it toward the direction of the engine; a branch channel branched from the fuel supply channel downstream of the fuel pump; a gas-liquid separation structure installed in the branch channel that separates the hydrogen fuel flowing into the branch channel into hydrogen gas and liquefied hydrogen; and a system for introducing and temporarily storing the hydrogen gas separated by the gas-liquid separation structure, and discharging the stored hydrogen gas at a predetermined timing with water. The system comprises a gas storage unit that supplies a gas to predetermined equipment other than the engine that uses a primary gas as fuel, a first control valve located downstream of the connection point with the branch passage in the fuel supply passage, a second control valve located upstream of the gas-liquid separation structure in the branch passage, and a controller. The controller opens the first control valve with the second control valve closed when hydrogen fuel supply to the engine is started, thereby starting the operation of the fuel pump, and closes the first control valve to stop the operation of the fuel pump and temporarily opens the second control valve when hydrogen fuel supply to the engine is stopped.

[0009] This disclosure provides a fuel supply system having the configuration described above, which can effectively utilize the fuel used in a hydrogen-fueled engine and minimize the rise in pressure within the fuel supply tank.

[0010] Figure 1 is a diagram showing a schematic configuration of a fuel supply system according to an embodiment of the present disclosure. Figure 2 is a diagram showing the open and closed states of each valve when hydrogen gas is stored in the hydrogen storage container in the schematic configuration of the fuel supply system. Figure 3 is a diagram showing the open and closed states of each valve when hydrogen gas is released from the hydrogen storage container in the schematic configuration of the fuel supply system. Figure 4 is a diagram showing a schematic configuration of a modified example of the fuel supply system according to an embodiment of the present disclosure.

[0011] Preferred embodiments of this disclosure will be described below with reference to the drawings. In the following description, identical or corresponding elements will be denoted by the same reference numerals throughout all drawings, and redundant descriptions may be omitted.

[0012] (Embodiment) Figure 1 is a diagram showing a schematic configuration of a fuel supply system according to an embodiment of the present disclosure. The fuel supply system 1 in this embodiment is a system that supplies fuel to an engine 11 that uses hydrogen as fuel. This fuel supply system 1 is installed, for example, in a ship, and the engine 11 is used as a drive source for the ship's propulsion system or the like. In Figure 1, the engine 11 is exemplified as a hydrogen-only engine, but the engine 11 may be a dual-fuel engine that operates by co-firing hydrogen and fuel oil, or a dual-fuel engine that operates by switching between hydrogen and fuel oil.

[0013] The fuel supply system 1 includes a fuel supply tank 2, a suction pump 3, a fuel pump 4, a gas-liquid separator 5 which is an example of a gas-liquid separation structure, a hydrogen storage container 6 as a gas storage container 6A, a heat source 7, valves V1 to V6, pressure sensors P1 and P2, and a controller 10, etc.

[0014] The fuel supply tank 2 stores liquefied hydrogen, which will be used as fuel for the engine 11. A fuel supply passage R1, which serves as the fuel flow path, is connected between the fuel supply tank 2 and the engine 11. In the fuel supply passage R1, a suction pump 3, a fuel pump 4, and a first control valve V1 are arranged in order from upstream. The suction pump 3 draws fuel from the fuel supply tank 2 into the fuel supply passage R1. The fuel pump 4 increases the pressure of the fuel drawn into the fuel supply passage R1 by the suction pump 3 to a predetermined pressure and sends it in the direction of the engine 11. Note that if the fuel pump 4 can smoothly draw fuel from the fuel supply tank 2 into the fuel supply passage R1 even without the suction pump 3, the suction pump 3 may be omitted.

[0015] The base end of a branch passage R2 is connected to the fuel supply passage R1 between the fuel pump 4 and the first control valve V1, and a gas-liquid separator 5 is connected to the tip of the branch passage R2. A second control valve V2 is located in the middle of the branch passage R2. The base end of a return passage R3 and the base end of a hydrogen gas introduction passage R4 are connected to the gas-liquid separator 5. The tip of the return passage R3 is located inside the fuel supply tank 2. The tip of the hydrogen gas introduction passage R4 is connected to the hydrogen storage container 6. A third control valve, a pressure regulating valve V3, is located in the middle of the hydrogen gas introduction passage R4. The pressure regulating valve V3 is a valve that adjusts the supply pressure of hydrogen gas supplied to the hydrogen storage container 6.

[0016] When the second control valve V2 is opened, the gas-liquid separator 5 separates the fuel flowing in from the fuel supply passage R1 through the branch passage R2 into liquefied hydrogen and hydrogen gas. The liquefied hydrogen is supplied to the fuel supply tank 2 through the return passage R3. The hydrogen gas is introduced to the hydrogen storage container 6 through the hydrogen gas introduction passage R4. A pump for transferring liquefied hydrogen from the gas-liquid separator 5 to the fuel supply tank 2 may be placed in the return passage R3.

[0017] The hydrogen storage container 6 is a container that houses a hydrogen storage material capable of absorbing and releasing hydrogen gas introduced through the hydrogen gas introduction channel R4. The hydrogen storage material can be a hydrogen storage alloy, as well as magnesium hydride, NaAlH ４ Or LiAlH４ Alkali metal alanates such as LiNH ２ or Li ３ Nonmetals such as metal amides (e.g., N), boron compounds, activated carbon, carbon nanotubes, and carbon nanofibers can be used. Examples of the boron compounds include alkali metal or alkaline earth metal boron hydride compounds and complexes of borane and ammonia.

[0018] Furthermore, a heat source 7 is connected to the hydrogen storage container 6. The heat source 7 can supply heat to the hydrogen storage material inside the hydrogen storage container 6 through heat exchange, thereby heating the hydrogen storage material.

[0019] A hydrogen gas supply channel R5 is connected to the hydrogen storage vessel 6 for supplying hydrogen gas to a predetermined device 12. A fourth control valve V4 is located in the middle of the hydrogen gas supply channel R5. The predetermined device 12 is a device that uses hydrogen gas as fuel, and examples include fuel cells, gas engine generators, hydrogen boilers, etc. The predetermined device 12 is also connected to a fuel supply main channel to which hydrogen gas is supplied in addition to the hydrogen gas supply channel R5. When hydrogen gas is not supplied from the hydrogen gas supply channel R5, the predetermined device 12 can be operated by the supply of hydrogen gas from the fuel supply main channel. Multiple such predetermined devices 12 may be provided.

[0020] Furthermore, a hydrogen gas discharge channel R7, which has a fifth control valve V5 positioned in the middle, is connected to the hydrogen storage vessel 6. The hydrogen gas discharge channel R7 merges with the hydrogen gas discharge channel R6, which is connected to the hydrogen gas introduction channel R4, and is connected to the hydrogen gas discharge channel R8. A sixth control valve V6 is positioned in the hydrogen gas discharge channel R8.

[0021] Furthermore, a pressure sensor P1 is positioned in the hydrogen gas introduction channel R4, and a pressure sensor P2 is positioned in the fuel supply channel R1. Pressure sensor P1 is a hydrogen gas pressure sensor that detects the supply pressure of hydrogen gas supplied to the hydrogen storage container 6. Pressure sensor P2 is an engine supply pressure sensor that detects the supply pressure of fuel supplied to the engine 11. The detection values ​​of these pressure sensors P1 and P2 are transmitted to the controller 10.

[0022] The controller 10 includes a computer such as a microcontroller, personal computer, or PLC (Programmable Logic Controller). More specifically, the controller 10 includes a processor, memory, and peripheral circuits. The processor includes, for example, a CPU or MPU. The memory includes ROM, RAM, registers, non-volatile storage, etc. The peripheral circuits include input / output interfaces, etc.

[0023] The memory of the controller 10 stores the control program. The controller 10 reads the control program from the memory and generates control signals to control the controlled object based on the control program. In other words, the controller 10 controls the suction pump 3, fuel pump 4, heat source 7, and valves V1 to V6. The controller 10 may be composed of a single controller for centralized control, or it may be composed of multiple controllers that cooperate with each other for distributed control. The controller 10 is also connected to the controller of the engine 11 in a communicative manner. Some or all of the circuits that make up the controller 10 may be configured as the controller of the engine 11.

[0024] With respect to the controller 10, the functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0025] Next, an example of control operation in the fuel supply system 1 will be described. In this example, when the engine 11 is started, a fuel supply command is transmitted from the engine 11 controller to the fuel supply system 1 controller 10, and when the engine 11 is stopped, a fuel supply stop command is transmitted from the engine 11 controller to the fuel supply system 1 controller 10. The fuel supply stop command includes a fuel supply stop command transmitted from the engine 11 controller when the engine 11 controller receives an emergency stop signal from a safety device, and a fuel supply stop command transmitted from the engine 11 controller when the operator performs an engine stop operation. In the following description, we will use the case where all valves V1 to V6 are in the closed state before the engine 11 is started as an example.

[0026] When the engine 11 is started, the controller 10 receives a fuel supply command and opens the first control valve V1 to drive pumps 3 and 4. As a result, liquefied hydrogen from the fuel supply tank 2 is supplied to the engine 11 through the fuel supply passage R1. Here, the liquefied hydrogen is pressurized to a predetermined pressure by the fuel pump 4, becoming supercritical before being supplied to the engine 11.

[0027] When the engine 11 is stopped, the controller 10 receives a fuel supply stop command and closes the first control valve V1 to stop the operation of pumps 3 and 4, while temporarily opening the second control valve V2 and the pressure regulating valve V3. However, when the first control valve V1 is closed and the operation of pumps 3 and 4 is stopped, it is not possible to immediately shut off the fuel supplied from the fuel pump 4. Therefore, the pressure in the passage between the fuel pump 4 and the first control valve V1 in the fuel supply passage R1 rises. By opening the second control valve V2, fuel is introduced to the gas-liquid separator 5 through the branch passage R2, and the rise in pressure in the passage can be eliminated. The open and closed states of each valve V1 to V6 at this time are shown in Figure 2.

[0028] The fuel introduced into the gas-liquid separator 5 is separated into liquefied hydrogen and hydrogen gas. The liquefied hydrogen is supplied to the fuel supply tank 2 through the return channel R3. The hydrogen gas is introduced into the hydrogen storage container 6 through the hydrogen gas introduction channel R4, where it is absorbed by a hydrogen storage material and temporarily stored.

[0029] Here, the controller 10 controls the opening degree of the pressure regulating valve V3 based on the value detected by the pressure sensor P1. Specifically, the controller 10 controls the opening degree of the pressure regulating valve V3 so that the value detected by the pressure sensor P1, i.e., the supply pressure of the hydrogen gas supplied to the hydrogen storage container 6, is within a predetermined range. Here, the predetermined range is the pressure range suitable for the hydrogen storage material in the hydrogen storage container 6 to absorb hydrogen gas, and it differs depending on the type of hydrogen storage material. Furthermore, even when the opening degree of the pressure regulating valve V3 is maximized, if the value detected by the pressure sensor P1 falls below the lower limit of the predetermined range, the controller 10 closes the pressure regulating valve V3 and the second control valve V2. This completes the process of storing hydrogen gas in the hydrogen storage container 6. Also, the temporary opening of the second control valve V2 ends.

[0030] The above describes the case where engine 11 is a hydrogen-only engine, but engine 11 may also be a dual-fuel engine that operates by co-firing hydrogen and fuel oil, or a dual-fuel engine that operates by switching between hydrogen and fuel oil. In the case where engine 11 is a dual-fuel engine that operates by switching between hydrogen and fuel oil, a fuel supply command is transmitted from the engine 11 controller to the controller 10 when starting operation with hydrogen as fuel and when switching the fuel from fuel oil to hydrogen during operation. In addition, a fuel supply stop command is transmitted from the engine 11 controller to the controller 10 when stopping operation and when switching the fuel from hydrogen to fuel oil and continuing operation.

[0031] Furthermore, in this embodiment, hydrogen gas is stored in the hydrogen storage container 6 not only when the engine 11 is stopped, but also when the load on the engine 11 decreases. This will be explained below.

[0032] When the load on engine 11 fluctuates during engine 11 operation, the amount of fuel consumed by engine 11 fluctuates. For example, when the load on engine 11 increases, fuel consumption increases and the detected value of pressure sensor P2 decreases. Conversely, when the load on engine 11 decreases, fuel consumption decreases and the detected value of pressure sensor P2 increases.

[0033] The controller 10 controls the first control valve V1 and the fuel pump 4 so that the value detected by the pressure sensor P2 becomes a predetermined target value. For example, if the load on the engine 11 increases and the value detected by the pressure sensor P2 falls below the target value, the controller 10 increases the opening of the first control valve V1 and increases the motor speed of the fuel pump 4 to increase the fuel flow rate of the fuel pump 4 so that the value detected by the pressure sensor P2 converges to the target value.

[0034] Furthermore, when the load on the engine 11 decreases and the value detected by the pressure sensor P2 exceeds the target value, the controller 10 reduces the opening of the first control valve V1 and lowers the motor speed of the fuel pump 4 to reduce the fuel flow rate of the fuel pump 4, so that the value detected by the pressure sensor P2 converges to the target value.

[0035] As described above, while the engine 11 is operating, the controller 10 adjusts the opening degree of the first control valve V1 and the motor rotation speed of the fuel pump 4 based on the detected value of the pressure sensor P2 and a target value. The target value is stored in advance in the memory of the controller 10.

[0036] Furthermore, when the load on the engine 11 decreases and the value detected by the pressure sensor P2 exceeds the target value, the controller 10 temporarily opens the second control valve V2 and the pressure regulating valve V3. Here, as described above, when the opening degree of the first control valve V1 is reduced and the motor rotation speed of the fuel pump 4 is lowered, it is not possible to immediately reduce the flow rate of fuel delivered from the fuel pump 4. Therefore, the pressure in the passage between the fuel pump 4 and the first control valve V1 in the fuel supply passage R1 increases. By opening the second control valve V2, fuel is introduced to the gas-liquid separator 5 through the branch passage R2, and the increase in pressure in the passage can be eliminated. The open / closed state of each valve V1 to V6 at this time can be changed by changing valve V1 to the open state in Figure 2, and the states of the other valves V2 to V6 are the same as described in Figure 2.

[0037] The fuel introduced into the gas-liquid separator 5 is separated into liquefied hydrogen and hydrogen gas. The liquefied hydrogen is supplied to the fuel supply tank 2 through the return channel R3. The hydrogen gas is introduced into the hydrogen storage container 6 through the hydrogen gas introduction channel R4 and is absorbed into the hydrogen storage material for temporary storage. When this hydrogen gas is absorbed into the hydrogen storage material, the heat source 7 may be configured to supply cold energy, and cold energy may be supplied from the heat source 7 to the hydrogen storage material. Here, the heat source that supplies cold energy may be provided separately from the heat source 7 that supplies heat.

[0038] Here, similar to the case where the engine 11 stops as described above, the controller 10 controls the opening of the pressure regulating valve V3 so that the value detected by the pressure sensor P1 falls within a predetermined range. Then, when the controller 10 opens the pressure regulating valve V3 to its maximum extent, if the value detected by the pressure sensor P1 falls below the lower limit of the predetermined range, it closes the pressure regulating valve V3 and the second control valve V2. This completes the process of storing hydrogen gas in the hydrogen storage container 6. Also, the temporary opening of the second control valve V2 ends.

[0039] In the above description, the case where the engine 11 is a hydrogen-only combustion engine has been explained. However, the engine 11 may be a dual-fuel engine that operates by co-combusting hydrogen and fuel oil, or may be a dual-fuel engine that operates by switching between hydrogen and fuel oil. When the engine 11 is a dual-fuel engine that operates by co-combusting hydrogen and fuel oil, the co-combustion ratio of hydrogen may be changed during operation.

[0040] Next, the case of supplying the hydrogen gas stored in the hydrogen storage container 6 to the predetermined device 12 will be described. The opening and closing states of each valve V1 to V6 at this time are shown in FIG. 3.

[0041] The controller 10 causes the hydrogen gas stored in the hydrogen storage container 6 to be supplied to the predetermined device 12 at a predetermined timing. In this case, the controller 10 opens the fourth control valve V4 disposed in the middle of the hydrogen gas supply passage R5, and supplies heat to the hydrogen storage material in the hydrogen storage container 6 by the heat source 7 to heat the hydrogen storage material to a predetermined temperature. The predetermined temperature varies depending on the type of the hydrogen storage material. As a result, hydrogen gas is released from the hydrogen storage material, and this hydrogen gas is supplied as fuel from the hydrogen storage container 6 to the predetermined device 12 through the hydrogen gas supply passage R5. The timing of supplying the hydrogen gas stored in the hydrogen storage container 6 to the predetermined device 12 can be determined in advance, for example, as the timing when a predetermined time has elapsed since the hydrogen gas was stored in the hydrogen storage container 6. In this case, as shown in FIG. 3, the first control valve V1 may be in an open state and the engine 11 may be operating, or the first control valve V1 may be in a closed state and the engine 11 may be stopped.

[0042] In the above description, the fifth and sixth control valves V5 and V6 are always closed. These valves V5 and V6 are normally closed, but are temporarily opened, for example, when the hydrogen gas absorption amount by the hydrogen storage material in the hydrogen storage container 6 reaches the limit when the second control valve V2 is opened. In addition, the hydrogen storage container 6 may be configured such that the maximum hydrogen gas absorption amount by the hydrogen storage material is sufficiently large, and the hydrogen gas discharge passages R6, R7, R8 and the control valves V5, V6 may be eliminated.

[0043] In this embodiment, since the hydrogen gas released from the hydrogen storage container 6 is supplied to a predetermined device 12 that uses hydrogen gas as fuel through the hydrogen gas supply flow path R5, it can be effectively utilized without wasting the hydrogen fuel. Instead of the predetermined device 12 that uses hydrogen gas as fuel, it is also possible to use a gas combustion unit abbreviated as "GCU" that burns and processes surplus gas. However, in this case, effective utilization of the hydrogen fuel cannot be achieved.

[0044] Further, in this embodiment, the hydrogen gas separated by the gas-liquid separator 5 is introduced into the hydrogen storage container 6 instead of the fuel supply tank 2, so that an increase in the pressure inside the fuel supply tank 2 can be suppressed as much as possible.

[0045] Also, in the fuel supply flow path R1 of this embodiment, a vaporizer that gasifies the fuel flowing through the fuel supply flow path R1 by heat exchange may be arranged between the connection portion of the fuel supply flow path R1 and the branch flow path R2 and the first control valve V1.

[0046] Further, in this embodiment, the engine 11 is used as a propulsion engine for a ship, and the configuration in which the fuel supply system 1, the engine 11, and the predetermined device 12 are provided on the ship is illustrated. However, the present invention is not limited to this. The fuel supply system 1, the engine 11, and the predetermined device 12 may be mounted on a vehicle such as an automobile. Further, the engine 11 may be used as an engine for a generator, and the fuel supply system 1, the engine 11, and the predetermined device 12 may be installed on land.

[0047] Furthermore, in this embodiment, a hydrogen storage container 6 was used as a gas storage container 6A for temporarily storing the hydrogen gas separated by the gas-liquid separator 5, but instead, a hydrogen gas tank 13 may be used as shown in Figure 4. In this case, for example, in the modified configuration shown in Figure 4, a hydrogen gas tank 13 is used instead of the hydrogen storage container 6 in Figure 1, and the heat source 7 and the hydrogen gas discharge passage R7 where the control valve V5 is located are removed. Furthermore, in this modified configuration, a pump 8 is placed in place of the pressure regulating valve V3 in the hydrogen gas introduction passage R4, and the pressure sensor P1 is removed. Also in this modified configuration, a pressure sensor P3 is placed in the fuel supply passage R1 between the fuel pump 4 and the first control valve V1. Furthermore, in this modified configuration, a pump 9 is placed in place of the control valve V4 in the hydrogen gas supply passage R5. In addition, the hydrogen gas discharge passages R6, R8 and the control valve V6 may be removed. Here, pumps 8 and 9 are controlled by the controller 10. Furthermore, the pressure sensor P3 detects the fuel pressure in the fuel supply passage R1 between the fuel pump 4 and the first control valve V1, and transmits the detected value to the controller 10.

[0048] As described above, the control operation in the fuel supply system when using the hydrogen gas tank 13 as the gas storage device 6A will be explained, mainly focusing on the differences from when using the hydrogen storage container 6.

[0049] When the engine 11 is started, the controller 10, upon receiving a fuel supply command, opens the first control valve V1 to drive the pumps 3 and 4, just as it would be if a hydrogen storage container 6 were used.

[0050] When the engine 11 is stopped, the controller 10 receives a fuel supply stop command and closes the first control valve V1 to stop the operation of pumps 3 and 4, while temporarily opening the second control valve V2 and driving pump 8 for approximately the same period that the second control valve V2 is open. As a result, the fuel in the fuel supply passage R1 is introduced to the gas-liquid separator 5 through the branch passage R2, and the liquefied hydrogen separated in the gas-liquid separator 5 is supplied to the fuel supply tank 2 through the return passage R3. The hydrogen gas separated in the gas-liquid separator 5 is also transported by pump 8 and introduced to the hydrogen gas tank 13, which is a gas storage device 6A, through the hydrogen gas introduction passage R4 for temporary storage.

[0051] At this point, when the pressure sensor P3 located in the fuel supply passage R1 detects a value below a predetermined value, the controller 10 closes the second control valve V2 and stops the pump 8 from operating. This completes the process of storing hydrogen gas in the hydrogen gas tank. At the same time, the temporary opening of the second control valve V2 is terminated.

[0052] Furthermore, hydrogen gas may be stored in the hydrogen gas tank not only when the engine 11 is stopped, but also when the load on the engine 11 decreases while the engine 11 is operating. This will be explained below.

[0053] While the engine 11 is operating, in the same manner as in the configuration using the hydrogen storage vessel 6, the controller 10 adjusts the opening degree of the first control valve V1 and the motor speed of the fuel pump 4 based on the detected value of the pressure sensor P2 and a target value, in order to respond to fluctuations in the load of the engine 11.

[0054] Furthermore, when the load on the engine 11 decreases and the value detected by the pressure sensor P2 exceeds the target value, the controller 10 temporarily opens the second control valve V2 and drives the pump 8 for approximately the same period that the second control valve V2 is open. As a result, the fuel in the fuel supply passage R1 is introduced to the gas-liquid separator 5 through the branch passage R2, and the liquefied hydrogen separated in the gas-liquid separator 5 is supplied to the fuel supply tank 2 through the return passage R3. The hydrogen gas separated in the gas-liquid separator 5 is also transported by the pump 8 and introduced to the hydrogen gas tank, which is the gas storage device 6A, through the hydrogen gas introduction passage R4 for temporary storage.

[0055] Here, similar to the case where the engine 11 stops as described above, when the pressure sensor P3 detects a value below a predetermined value, the controller 10 closes the second control valve V2 and stops the pump 8 from running. This completes the process of storing hydrogen gas in the hydrogen gas tank. Also, the temporary opening of the second control valve V2 ends.

[0056] The above describes the case where engine 11 is a hydrogen-only engine, but engine 11 may also be a dual-fuel engine that operates by co-firing hydrogen and fuel oil, or a dual-fuel engine that operates by switching between hydrogen and fuel oil. If engine 11 is a dual-fuel engine that operates by switching between hydrogen and fuel oil, a fuel supply command is sent from the engine 11 controller to the controller 10 when starting operation with hydrogen as fuel and when switching the fuel from fuel oil to hydrogen during operation. In addition, a fuel supply stop command is sent from the engine 11 controller to the controller 10 when stopping operation and when switching the fuel from hydrogen to fuel oil and continuing operation. Furthermore, if engine 11 is a dual-fuel engine that operates by co-firing hydrogen and fuel oil, the hydrogen co-firing ratio may be changed during operation.

[0057] Next, we will explain the case in which hydrogen gas stored in a hydrogen gas tank is supplied to a predetermined device 12.

[0058] The controller 10 supplies hydrogen gas stored in the hydrogen gas tank to a predetermined device 12 at a predetermined timing. In this case, the controller 10 drives the pump 9 located in the hydrogen gas supply channel R5, thereby supplying hydrogen gas from the hydrogen gas tank to the predetermined device 12 as fuel through the hydrogen gas supply channel R5.

[0059] As described above, a hydrogen gas tank 13 may be used as the gas storage device 6A, but since the hydrogen storage material in the hydrogen storage container 6 can absorb a large amount of hydrogen gas relative to its volume, using the hydrogen storage container 6 allows for a smaller gas storage device 6A. Therefore, it is preferable to use the hydrogen storage container 6 when applying it to ships, etc.

[0060] In the above embodiment, a gas-liquid separator 5 was given as an example of a gas-liquid separation structure, but it is not limited to this. As a gas-liquid separation structure, for example, a first branch pipe, which is a pipe constituting the branch passage R2, may be arranged horizontally or substantially horizontally, and a second branch pipe that further branches off may be connected to the lower part of this first branch pipe. Here, the downstream end of the first branch pipe is connected to the pipe of the hydrogen gas introduction passage R4. In this case, when the second control valve V2 is opened, the liquid portion of the hydrogen fuel that flows from the fuel supply passage R1 into the first branch pipe, which is the branch passage R2, falls into the second branch pipe, thereby separating the incoming hydrogen fuel into hydrogen gas and liquefied hydrogen. Furthermore, if the downstream end of the second branch pipe is configured to be introduced into the fuel supply tank 2, the separated liquefied hydrogen can be supplied to the fuel supply tank 2.

[0061] From the above description, many improvements and other embodiments of the disclosure will be apparent to those skilled in the art. Therefore, the above description should be interpreted as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the disclosure. The details of its structure and / or function can be substantially modified without departing from the spirit of the disclosure.

[0062] (Summary of the Disclosure) A fuel supply system according to a first aspect of the Disclosure includes a fuel supply tank for storing liquefied hydrogen, a fuel pump located in a fuel supply channel that supplies the liquefied hydrogen from the fuel supply tank to an engine as hydrogen fuel and pressurizes the hydrogen fuel and sends it toward the direction of the engine, a branch channel branched from the fuel supply channel downstream of the fuel pump, a gas-liquid separation structure installed in the branch channel that separates the hydrogen fuel flowing into the branch channel into hydrogen gas and liquefied hydrogen, and a system that introduces the hydrogen gas separated by the gas-liquid separation structure for temporary storage and uses the stored hydrogen gas as fuel at a predetermined timing. The system includes a gas storage device that supplies gas to predetermined equipment other than the engine, a first control valve located downstream of the connection portion with the branch passage in the fuel supply passage, a second control valve located upstream of the gas-liquid separation structure in the branch passage, and a controller. The controller opens the first control valve with the second control valve closed when hydrogen fuel supply to the engine is started, thereby starting the operation of the fuel pump, and closes the first control valve to stop the operation of the fuel pump and temporarily opens the second control valve when hydrogen fuel supply to the engine is stopped.

[0063] With this configuration, when the hydrogen fuel supply to the engine is stopped, such as when the engine is stopped, the second control valve is temporarily opened, allowing the hydrogen fuel in the flow path between the fuel pump and the first control valve in the fuel supply flow path to be introduced into the gas-liquid separation structure through the branched flow path, thereby eliminating the pressure rise in the flow path. Furthermore, the hydrogen gas separated by the gas-liquid separation structure is temporarily stored in a gas storage device and then supplied to a predetermined device that uses hydrogen gas as fuel at a predetermined timing. Thus, efficient utilization of hydrogen fuel can be achieved. In addition, since the hydrogen gas separated by the gas-liquid separation structure is introduced into the gas storage device rather than the fuel supply tank, the pressure rise in the fuel supply tank can be kept to a minimum.

[0064] A fuel supply system according to a second aspect of the present disclosure is a fuel supply system according to a first aspect, further comprising an engine supply pressure sensor located downstream of the first control valve in the fuel supply passage for detecting the supply pressure of hydrogen fuel supplied to the engine, wherein, during engine operation, if the detected value of the engine supply pressure sensor exceeds a target value, the controller reduces the opening of the first control valve to reduce the flow rate delivered to the fuel pump and temporarily opens the second control valve.

[0065] In this configuration, when the engine load decreases and the detected value of the engine supply pressure sensor exceeds the target value, the opening of the first control valve decreases, thereby reducing the flow rate delivered to the fuel pump, and the second control valve is temporarily opened. This eliminates the pressure rise in the flow path between the fuel pump and the first control valve in the fuel supply passage, and allows the liquefied hydrogen separated by the gas-liquid separation structure to be stored in the gas storage device.

[0066] A fuel supply system according to a third aspect of this disclosure is a fuel supply system according to a first or second aspect, wherein the gas storage device is a hydrogen storage container that houses a hydrogen storage material capable of absorbing and releasing hydrogen gas within the container. This makes it possible to miniaturize the gas storage device.

[0067] A fuel supply system according to a fourth aspect of this disclosure is a fuel supply system according to a third aspect, comprising: a hydrogen gas introduction channel which is a channel through which hydrogen gas separated by the gas-liquid separation structure is introduced into the hydrogen storage container; a pressure regulating valve disposed in the hydrogen gas introduction channel which adjusts the supply pressure of the hydrogen gas supplied to the hydrogen storage container; a hydrogen gas pressure sensor disposed in the hydrogen gas introduction channel which detects the supply pressure of the hydrogen gas supplied to the hydrogen storage container; a heat source which supplies heat to the hydrogen storage material in order to release hydrogen gas from the hydrogen storage material; and The device further includes a hydrogen gas supply channel for supplying hydrogen gas from the hydrogen storage container to the predetermined device. When the second control valve is open, the controller controls the opening of the pressure regulating valve so that the detected value of the hydrogen gas pressure sensor is within a predetermined range. When the opening of the pressure regulating valve is maximized, if the detected value of the hydrogen gas pressure sensor falls below the lower limit of the predetermined range, the controller closes the pressure regulating valve and the second control valve. When supplying hydrogen gas from the hydrogen storage container to the predetermined device, the controller causes the heat source to supply heat to the hydrogen storage material. This allows for efficient storage of hydrogen gas in the hydrogen storage container and efficient supply of hydrogen gas from the hydrogen storage container to the predetermined container.

[0068] 1. Fuel supply system 2. Fuel supply tank 4. Fuel pump 5. Gas-liquid separator 6A. Gas storage unit 6. Hydrogen storage vessel 7. Heat source 10. Controller 11. Engine 12. Designated equipment

Claims

1. A fuel supply tank for storing liquefied hydrogen; a fuel pump located in a fuel supply passage that supplies the liquefied hydrogen from the fuel supply tank to the engine as hydrogen fuel, which pressurizes the hydrogen fuel and sends it in the direction of the engine; a branch passage branched off from the fuel supply passage downstream of the fuel pump; a gas-liquid separation structure installed in the branch passage which separates the hydrogen fuel flowing into the branch passage into hydrogen gas and liquefied hydrogen; a gas storage device which introduces the hydrogen gas separated by the gas-liquid separation structure for temporary storage and supplies the stored hydrogen gas to predetermined equipment other than the engine that uses hydrogen gas as fuel at predetermined timings; a first control valve located downstream of the connection portion with the branch passage in the fuel supply passage; a second control valve located upstream of the gas-liquid separation structure in the branch passage; and a controller, wherein the controller is A fuel supply system that, when hydrogen fuel is supplied to the engine, opens the first control valve with the second control valve closed to start driving the fuel pump, and when hydrogen fuel is supplied to the engine, closes the first control valve to stop driving the fuel pump and temporarily opens the second control valve.

2. The fuel supply system according to claim 1, comprising an engine supply pressure sensor located downstream of the first control valve in the fuel supply passage for detecting the supply pressure of hydrogen fuel supplied to the engine, wherein the controller, during engine operation, reduces the opening of the first control valve to reduce the flow rate delivered to the fuel pump and temporarily opens the second control valve when the detected value of the engine supply pressure sensor exceeds a target value.

3. The fuel supply system according to claim 1 or 2, wherein the gas storage device is a hydrogen storage container that houses a hydrogen storage material capable of absorbing and releasing hydrogen gas within the container.

4. The controller further comprises: a hydrogen gas introduction channel, which is a channel through which hydrogen gas separated by the gas-liquid separation structure is introduced into the hydrogen storage container; a pressure regulating valve arranged in the hydrogen gas introduction channel and adjusting the supply pressure of hydrogen gas supplied to the hydrogen storage container; a hydrogen gas pressure sensor arranged in the hydrogen gas introduction channel and detecting the supply pressure of hydrogen gas supplied to the hydrogen storage container; a heat source that supplies heat to the hydrogen storage material in order to release hydrogen gas from the hydrogen storage material; and a hydrogen gas supply channel that supplies the hydrogen gas released from the hydrogen storage material from the hydrogen storage container to the predetermined equipment, wherein when the second control valve is open, the controller controls the opening of the pressure regulating valve so that the detected value of the hydrogen gas pressure sensor is within a predetermined range, and closes the pressure regulating valve and the second control valve if the detected value of the hydrogen gas pressure sensor falls below the lower limit of the predetermined range even when the opening of the pressure regulating valve is at its maximum, The fuel supply system according to claim 3, wherein when hydrogen gas is supplied from the hydrogen storage container to the predetermined equipment, the heat source is used to supply heat to the hydrogen storage material.

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