Work vehicles

Abstract

A work vehicle according to the present invention comprises a fuel cell and a fuel tank module. The fuel tank module comprises: a plurality of fuel tanks containing fuel supplied to the fuel cell; a valve system connected to the plurality of fuel tanks; and a tank case accommodating the plurality of fuel tanks and the valve system. The plurality of fuel tanks includes a first fuel tank having a first length in a first direction, and a second fuel tank having a second length in the first direction, the second length being shorter than the first length. The first fuel tank and the second fuel tank are arranged in a second direction perpendicular to the first direction, and at least a portion of the valve system is arranged, inside the tank case, in a space formed between the second fuel tank and the tank case.

Description

Technical Field

[0001] The present disclosure relates to a work vehicle including an electric motor and a fuel cell.

Background Art

[0002] In the field of automobiles whose main purpose is to move "people" or "objects", electric vehicles (EVs) that generate driving force (traction) for running by an electric motor (hereinafter referred to as "motor") instead of an internal combustion engine are becoming popular.

[0003] On the other hand, in order to realize a decarbonized society, it is also required to reduce the amount of carbon dioxide (CO2) emitted by work vehicles such as tractors used in fields. Different from general automobiles, in work vehicles such as tractors, it is necessary to tow a working machine called an implement to perform agricultural work such as tilling. Therefore, in order to realize the electrification of work vehicles, there are problems to be solved different from the electrification of passenger vehicles.

[0004] Patent Document 1 discloses a tractor including a fuel cell (FC) power generation system and a motor without significantly changing the structure of a conventional engine-driven tractor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To implement a fuel cell-based power generation system for work vehicles, various components are needed in addition to a fuel tank for storing fuel. However, unlike ordinary automobiles, work vehicles have mechanical structures for towing, lifting, and rotating implements, for example. Therefore, there is a challenge in that the configuration of conventional electric vehicle fuel cell power generation systems cannot be directly adopted for work vehicles.

[0007] This disclosure provides a work vehicle that can solve these problems. [Means for solving the problem]

[0008] In exemplary and non-limiting embodiments, the work vehicle according to the present disclosure is a work vehicle comprising a fuel cell and a fuel tank module, the fuel tank module comprising a plurality of fuel tanks for containing fuel to be supplied to the fuel cell, a valve system connected to the plurality of fuel tanks, and a tank case housing the plurality of fuel tanks and the valve system. The plurality of fuel tanks include a first fuel tank having a first length in a first direction and a second fuel tank having a second length shorter than the first length in the first direction. The first and second fuel tanks are arranged in a second direction perpendicular to the first direction, and at least a portion of the valve system is located within the tank case in a space formed between the second fuel tank and the tank case. [Effects of the Invention]

[0009] According to embodiments of this disclosure, a space suitable for housing components can be formed within the tank case, and this space can be used as a valve space. By arranging several valves, such as on-off valves and pressure reducing valves, in the valve space, the functionality of the fuel tank module can be enhanced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic plan view showing an example of the basic configuration of a work vehicle according to this disclosure. [Figure 2] This figure shows a basic example configuration of a fuel cell power generation system installed in a work vehicle. [Figure 3] This is a schematic block diagram illustrating an example of electrical connections and power transmission between components of a work vehicle according to this disclosure. [Figure 4] This block diagram schematically shows the electrical signal paths (thin solid lines) and coolant paths (dotted lines) between components in the work vehicle according to this disclosure. [Figure 5] This is a schematic side view showing an example of the configuration of a work vehicle in an embodiment of the present disclosure. [Figure 6A] This is a schematic side view illustrating an example of the arrangement of the main components in a work vehicle according to an embodiment of the present disclosure. [Figure 6B] This is a schematic plan view showing an example of the arrangement of the main components in a work vehicle according to an embodiment of the present disclosure. [Figure 7] This figure schematically shows a mechanism for supporting a fuel tank in an embodiment of the present disclosure. [Figure 8] This figure schematically shows an example of the configuration of a fuel tank module in an embodiment of the present disclosure. [Figure 9A] This figure schematically shows the arrangement of fuel gas sensors in the front housing and tank case in embodiments of the present disclosure. [Figure 9B] This figure schematically shows an example of the arrangement of the first sensor inside the front housing in an embodiment of the present disclosure. [Figure 10] This is a schematic side view showing an example of the arrangement of a radiator device in an embodiment of the present disclosure. [Figure 11] This is a schematic plan view showing an example of the arrangement of a radiator device in an embodiment of the present disclosure. [Figure 12] This is a perspective view of an agricultural tractor in an embodiment of the present disclosure (hereinafter referred to as "this embodiment"). [Figure 13] This is a side view of the agricultural tractor in this embodiment. [Figure 14] It is a plan view of an agricultural tractor in this embodiment. [Figure 15] It is a front view of an agricultural tractor in this embodiment. [Figure 16] It is a rear view of an agricultural tractor in this embodiment. [Figure 17] It is a side view of an agricultural tractor in which the front housing is in an open state in this embodiment. [Figure 18] It is a side view of an agricultural tractor in which the front housing is in an open state in a modified example. [Figure 19] It is a side view schematically showing the movable range of the movable housing part in a form in which the rotating shaft is located at the front part of the movable housing part. [Figure 20] It is a side view schematically showing the movable range of the movable housing part in a form in which the rotating shaft is located at the rear part of the movable housing part. [Figure 21] It is a perspective view of the fixed housing part in this embodiment. [Figure 22] It is a side view of the fixed housing part in this embodiment. [Figure 23] It is a view showing the arrangement relationship between the fixed housing part and the handle stay bar in this embodiment. [Figure 24] It is a perspective view showing the arrangement of the inverter device in this embodiment. [Figure 25] It is a perspective view showing the arrangement relationship between the inverter device and the transmission case in this embodiment. [Figure 26] It is a rear view showing the arrangement relationship between the inverter device and the transmission case in this embodiment. [Figure 27] It is a top view showing the arrangement relationship between the inverter device and the transmission case in this embodiment. [Figure 28] It is a side view showing the electric circuit module in this embodiment. [Figure 29] It is a view schematically showing the configuration of the electric circuit module in this embodiment.

Modes for Carrying Out the Invention

[0011] Embodiments of the present disclosure are described below. However, descriptions that are unnecessarily detailed may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid the following description becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and do not intend to limit the subject matter described in the claims by means of these. In the following description, components having the same or similar function are denoted by the same reference numerals.

[0012] The embodiments described below are illustrative, and the technology of this disclosure is not limited to the embodiments described below. For example, the numerical values, shapes, materials, steps, the order of those steps, the layout of the display screen, etc., shown in the embodiments below are merely examples, and various modifications are possible as long as they do not result in a technical inconsistency. Furthermore, it is possible to combine one embodiment with another as long as it does not result in a technical inconsistency.

[0013] In this disclosure, “work vehicle” means a vehicle used to perform work at a work site. “Work site” is any place where work is performed, such as a field, forest, or construction site. “Field” is any place where agricultural work is performed, such as an orchard, farm, rice paddy, grain farm, or pasture. A work vehicle may be agricultural machinery such as a tractor, rice transplanter, combine harvester, riding cultivator, or riding lawnmower, or a vehicle used for purposes other than agriculture, such as a construction vehicle or snowplow. In this disclosure, a work vehicle may be fitted with implements (also called “working equipment” or “working device”) on at least one of its front and rear, depending on the work being performed. The act of a work vehicle driving while performing work may be referred to as “working drive”.

[0014] The term "agricultural machinery" refers to machines used for agricultural purposes. Examples of agricultural machinery include tractors, harvesters, rice transplanters, riding cultivators, vegetable transplanters, mowers, seeders, fertilizer spreaders, and agricultural mobile robots. Agricultural machinery can function not only when a work vehicle like a tractor functions on its own, but also when implements attached to or towed by the work vehicle, along with the entire work vehicle, function as a single piece of agricultural machinery. Agricultural machinery performs agricultural tasks on the ground in a field, such as tilling, sowing, pest control, fertilizing, planting crops, or harvesting.

[0015] 1. <Basic configuration of the work vehicle> Before specifically describing the embodiments of the work vehicle in this disclosure, we will explain the basic configuration and operation examples of the work vehicle in this disclosure. The work vehicle described below is equipped with a motor and a fuel cell power generation system (hereinafter referred to as the "FC power generation system") that generates the power necessary to drive the motor.

[0016] Figure 1 is a schematic plan view illustrating an example of the basic configuration of the work vehicle 100 in this disclosure. In this disclosure, the direction of travel when the work vehicle 100 is traveling straight forward is referred to as the "forward direction," and the direction of travel when it is traveling straight backward is referred to as the "rear direction." In a plane parallel to the ground, the direction extending perpendicularly to the right relative to the "forward direction" is referred to as the "right direction," and the direction extending perpendicularly to the left is referred to as the "left direction." In Figure 1, the "forward direction," "rear direction," "right direction," and "left direction" are indicated by the arrows "forward," "rear," "right," and "left," respectively. The forward and rear directions may be collectively referred to as the "forward-backward direction," and the right and left directions may be collectively referred to as the "width direction."

[0017] In the illustrated example, the work vehicle 100 is, for example, a tractor, which is an example of agricultural machinery. The technology of this disclosure is not limited to work vehicles such as tractors, but can be applied to other types of work vehicles. The work vehicle 100 can travel in a field while carrying or towing an implement and performing agricultural work according to the type of implement. The work vehicle 100 can also travel in and out of a field (including roads) with the implement lifted or without the implement attached.

[0018] The work vehicle 100, like a conventional tractor, is equipped with a body (vehicle frame) 102 that rotatably supports the left and right front wheels 104F and the left and right rear wheels 104R. The body 102 includes a front frame 102A on which the front wheels 104F are mounted and a transmission case 102B on which the rear wheels 104R are mounted. The front frame 102A is fixed to the front of the transmission case 102B. The front wheels 104F and the rear wheels 104R may be collectively referred to as wheels 104. Strictly speaking, wheels 104 are wheels on which tires are mounted. In this disclosure, “wheel” generally means the entire “wheel and tire.” One or both of the front wheels 104F and the rear wheels 104R may be replaced with multiple wheels (crawlers) equipped with tracks instead of wheels with tires.

[0019] In the example shown in Figure 1, the work vehicle 100 is equipped with a fuel cell module (FC module) 10 and a motor 70, which are directly or indirectly supported by a front frame 102A. The FC module 10 has a fuel cell stack (FC stack) and functions as an on-board generator that generates electricity from fuel, as will be described later. Hereinafter, "FC module" or "FC stack" may be simply referred to as "fuel cell".

[0020] The motor 70 is electrically connected to the FC module 10. The motor 70 can convert the power generated in the FC module 10 into mechanical motion (power) to generate the driving force (traction) necessary for the work vehicle 100 to move. An example of the motor 70 is an AC synchronous motor. Since the FC stack of the FC module 10 generates DC current, if the motor 70 is an AC synchronous motor, a group of electrical circuits including an inverter device is provided between the FC stack and the motor 70 to convert the DC current to AC current. Some of these electrical circuits may be located inside the FC module 10. Other parts of the electrical circuits may be attached to the motor 70 as a drive circuit for the motor 70.

[0021] The motor 70 has a rotating output shaft 71. The torque of the output shaft 71 is transmitted to the rear wheels 104R via mechanical components such as a transmission (speed changer) and a rear-wheel differential gear, which are located inside the transmission case 102B. In other words, the power generated by the motor 70, which is the power source, is transmitted to the rear wheels 104R by a power transmission system (drivetrain) 74, which includes a transmission, located inside the transmission case 102B. For this reason, the "transmission case" may also be called the "transmission case". In four-wheel drive mode, a portion of the power from the motor 70 is also transmitted to the front wheels 104F. The power from the motor 70 can be used not only for driving the work vehicle 100 but also for driving implements. Specifically, a power take-off (PTO) shaft 76 is provided at the rear end of the transmission case 102B, and the torque from the output shaft 71 of the motor 70 is transmitted to the PTO shaft 76. The implement, which is mounted on or towed by the work vehicle 100, receives power from the PTO shaft 76 and can perform various operations according to the task. The motor 70 and the power transmission system 74 may be collectively referred to as the electric powertrain.

[0022] Thus, the work vehicle 100 according to this disclosure is not equipped with an internal combustion engine such as a diesel engine, but is equipped with an FC module 10 and a motor 70. Furthermore, the output shaft 71 of the motor 70 is mechanically coupled to a power transmission system 74, such as a transmission, in a transmission case 102B. The motor 70 can efficiently generate torque over a relatively wide rotational speed range compared to an internal combustion engine. However, by using the power transmission system 74, including the transmission, it becomes easy to adjust the torque and rotational speed from the motor 70 over an even wider range by performing multi-stage or continuously variable speed operation. Therefore, it becomes possible to efficiently perform not only the driving of the work vehicle 100 but also a variety of tasks using implements.

[0023] Furthermore, depending on the intended use or size of the work vehicle 100, some functions of the power transmission system 74 may be omitted. For example, some or all of the transmission responsible for the speed change function may be omitted. The number and mounting positions of the motors 70 are also not limited to the example shown in Figure 1.

[0024] The work vehicle 100 is equipped with at least one fuel tank 50 that contains fuel to be supplied to the FC module 10. In Figure 1, for simplicity, one fuel tank 50 is shown. In one embodiment, multiple fuel tanks 50 are housed in a tank case to constitute a fuel tank module. The fuel tanks 50 are supported by members fixed to the vehicle body 102, as will be described later. The FC module 10 and the fuel tanks 50 are connected by piping and valves, etc., to form an on-board FC power generation system. The configuration and operation of the FC power generation system will be described later.

[0025] The work vehicle 100 in the embodiments described below includes a driver's seat supported by a vehicle body 102. The driver's seat can be surrounded by a cabin supported by the vehicle body 102. In the embodiments described below, the FC module 10 is disposed in front of the driver's seat, and the fuel tank 50 is disposed above the driver's seat. Such an FC module 10 and fuel tank 50 are housed in at least one "accommodator". The "accommodator" functions as, for example, a housing and serves to protect the FC module 10 and the fuel tank 50 from sunlight irradiation and wind and rain. Further, when fuel gas leaks from the FC module 10 or the fuel tank 50, such an accommodator can also control the spread of the fuel gas into the atmosphere and facilitate the detection of the fuel gas.

[0026] The FC module 10 can be housed in, for example, a front housing called a "bonnet". The front housing is a part of the "accommodator". The front housing is supported by a front portion (front frame 102A) of the vehicle body 102. The fuel tank 50 can be housed in a tank case as described above. The tank case is supported directly or indirectly by the vehicle body 102.

[0027] 2. <FC Power Generation System> Next, referring to FIG. 2, a basic configuration example of the FC power generation system 180 mounted on the work vehicle 100 will be described.

[0028] The FC power generation system 180 shown in FIG. 2 functions as an in-vehicle power generation system in the work vehicle 100 of FIG. 1. The electric power generated by the power generation of the FC power generation system 180 is used not only for the running of the work vehicle 100 but also for the operation of an implement towed or mounted by the work vehicle 100.

[0029] The FC power generation system 180 in the illustrated example includes an FC module 10 and at least one fuel tank 50 that stores fuel supplied to the FC module 10. Further, the FC power generation system 180 includes a radiator device 34 for cooling the FC module 10.

[0030] The FC module 10 comprises, as its main components, a fuel cell stack (FC stack) 11, an air compressor 12, a fuel circulation pump 24, a coolant pump 31, a boost circuit 40, and a control device 42. These components are housed within the casing of the FC module 10 and are connected to each other by electrical or fluid communication.

[0031] The FC stack 11 generates electricity through an electrochemical reaction between the fuel, "anode gas," and the oxidizing gas, "cathode gas." In this example, the FC stack 11 is a polymer electrolyte fuel cell. The FC stack 11 has a stack structure in which multiple single cells are stacked. Each single cell comprises, for example, an electrolyte membrane formed from an ion exchange membrane, an anode electrode formed on one side of the electrolyte membrane, a cathode electrode formed on the other side of the electrolyte membrane, and a pair of separators that sandwich the anode electrode and cathode electrode from both sides. The voltage generated in a single cell is, for example, less than 1 volt. Therefore, in the FC stack 11, for example, more than 300 single cells are connected in series to generate a voltage of several hundred volts.

[0032] The anode electrode of the FC stack 11 is supplied with an anode gas. The anode gas is called the "fuel gas" or simply "fuel." In embodiments of this disclosure, the anode gas (fuel) is hydrogen gas. The cathode electrode is supplied with a cathode gas. The cathode gas is an oxidizing gas such as air. The anode electrode is called the fuel electrode, and the cathode electrode is called the air electrode.

[0033] At the anode, the electrochemical reaction shown in equation (1) below occurs. 2H2→4H + +4e - ...Equation (1)

[0034] At the cathode electrode, the electrochemical reaction shown in equation (2) below occurs. 4H + +4e - +O2→2H2O...Equation (2)

[0035] Overall, the reaction shown in equation (3) below occurs. 2H2+O2→2H2O...Equation (3)

[0036] The anode gas remaining after being used in the above reaction is called the "anode-off gas," and the cathode gas remaining after being used in the reaction is called the "cathode-off gas."

[0037] The air compressor 12 supplies air taken in from the outside as cathode gas to the cathode electrode of the FC stack 11. The cathode gas supply system, including the air compressor 12, has a cathode gas supply pipe 13, a cathode off gas pipe 14, and a bypass pipe 15. The cathode gas supply pipe 13 flows the cathode gas (air) supplied from the air compressor 12 to the cathode electrode of the FC stack 11. The cathode off gas pipe 14 flows the cathode off gas discharged from the FC stack 11 to the outside air. The bypass pipe 15 branches off from the cathode gas supply pipe 13 downstream of the air compressor 12, bypasses the FC stack 11, and connects to the cathode off gas pipe 14. The bypass pipe 15 is equipped with a control valve 16 that adjusts the flow rate of cathode gas flowing through the bypass pipe 15. The cathode gas supply pipe 13 is equipped with a shut-off valve 17 that selectively blocks the inflow of cathode gas into the FC stack 11. The cathode-off gas pipe 14 is equipped with a pressure regulating valve 18 for adjusting the back pressure of the cathode gas.

[0038] The cathode gas supply system of the FC module 10 is equipped with a rotation speed detection sensor S1 for detecting the rotation speed of the air compressor 12 and a gas flow rate detection sensor S2 for detecting the flow rate of cathode gas flowing through the cathode gas supply pipe 13. The control valve 16, shut-off valve 17, and pressure regulating valve 18 are, for example, solenoid valves.

[0039] The fuel circulation pump 24 supplies fuel gas (anode gas) sent from the fuel tank 50 to the anode electrode of the FC stack 11. The anode gas supply system, including the fuel circulation pump 24, has an anode gas supply pipe 21, an anode off-gas pipe 22, and a circulation passage 23. The anode gas supply pipe 21 flows the anode gas supplied from the fuel tank 50 to the anode electrode of the FC stack 11. In the embodiment of this disclosure, the fuel tank 50 is a hydrogen tank for storing high-pressure hydrogen gas.

[0040] The anode-off gas pipe 22 carries the anode-off gas discharged from the FC stack 11. The anode-off gas is guided through the anode-off gas pipe 22 to the gas-liquid separator 25 where moisture is removed. The anode-off gas from which moisture has been removed is returned to the anode gas supply pipe 21 through the circulation channel 23 by the fuel circulation pump 24. The anode-off gas circulating in the circulation channel 23 can be discharged through the anode-off gas pipe 22 by opening the exhaust valve 26. Moisture stored in the gas-liquid separator 25 can be discharged through the anode-off gas pipe 22 by opening the exhaust valve 26. The exhaust valve 26 is, for example, a solenoid valve. In the example shown in the figure, the anode-off gas pipe 22 is connected to the cathode-off gas pipe 14. By adopting such a configuration, it is possible to improve the utilization efficiency of anode gas by circulating the anode-off gas, including unreacted anode gas that did not contribute to the electrochemical reaction, and supplying it back to the FC stack 11.

[0041] Temperature control is crucial for enhancing the performance of the FC stack 11. Since heat is generated when electricity is produced through the reaction of hydrogen and oxygen gases to create water, cooling is necessary. Figure 2 shows a coolant circulation system including a coolant pump 31 for the FC stack 11, but as will be described later, cooling circulation systems for other electrical components may also be provided. The air compressor 12, fuel circulation pump 24, and coolant pump 31 in the FC module 10 are each operated by their own built-in motors. These motors are also electrical components.

[0042] The coolant circulation system shown in Figure 2, including the coolant pump 31, comprises a coolant supply pipe 32, a coolant discharge pipe 33, a radiator device 34, and a temperature sensor S3. This coolant circulation system can adjust the temperature of the FC stack 11 within a predetermined range by circulating the coolant through the FC stack 11. The coolant is supplied to the FC stack 11 through the coolant supply pipe 32. The supplied coolant flows through coolant flow paths formed between the individual cells and is discharged to the coolant discharge pipe 33. The coolant discharged to the coolant discharge pipe 33 flows to the radiator device 34. The radiator device 34 dissipates heat from the coolant by exchanging heat between the incoming coolant and the outside air, and supplies the cooled coolant back to the coolant supply pipe 32.

[0043] The coolant pump 31 is installed in the coolant supply pipe 32 or the coolant discharge pipe 33 to deliver coolant to the FC stack 11. A coolant bypass passage may be provided between the coolant discharge pipe 33 and the coolant supply pipe 32. In this case, a flow divider valve is provided at the branching point where the coolant bypass passage branches off from the coolant discharge pipe 33. The flow divider valve can adjust the flow rate of coolant flowing through the bypass passage. The temperature sensor S3 detects the temperature of the coolant flowing through the coolant discharge pipe 33.

[0044] The coolant used to cool the FC stack 11 is circulated through a flow path by an electric coolant pump (coolant pump) 31. A coolant control valve may be provided downstream of the FC stack 11. The coolant control valve adjusts the ratio of coolant flowing to the radiator unit 34 to coolant bypassing the radiator unit 34, enabling more precise control of the coolant temperature. Furthermore, by controlling the amount of coolant supplied by the coolant pump, it is also possible to control the temperature difference between the coolant at the inlet and outlet of the FC stack 11 to stay within a desired range. The temperature of the coolant in the FC stack 11 can be controlled to a temperature that maximizes the power generation efficiency of the FC stack 11, for example, around 70°C.

[0045] The coolant flowing through the FC stack 11 preferably has higher insulating properties than the coolant used to cool ordinary electrical components. Since high voltages, for example, exceeding 300 volts, are generated in the FC stack 11, increasing the electrical resistance of the coolant can suppress current leakage through the coolant or the radiator device 34. The electrical resistance of the coolant may decrease as it is used. This is because ions dissolve into the coolant flowing through the FC stack 11. To remove such ions from the coolant and improve its insulating properties, it is desirable to place an ion exchanger in the coolant flow path.

[0046] The boost circuit 40 can raise the voltage output from the FC stack 11 by the power generation operation to a desired level. The downstream stage of the boost circuit 40 is connected to a high-voltage electrical circuit including an inverter device for motor drive. As will be described later, the downstream stage of the boost circuit 40 can also be connected in parallel to a low-voltage electrical circuit via a step-down circuit.

[0047] The control device 42 is an electronic control unit (ECU) that controls power generation by the FC module 10. The control device 42 detects or estimates the operating state of the FC power generation system 180 based on signals output from various sensors. Based on the operating state of the FC power generation system 180 and commands output from a higher-level computer or other ECU, the control device 42 controls the operation of the air compressor 12, fuel circulation pump 24, coolant pump 31, and various valves to control power generation by the FC stack 11. The control device 42 includes, for example, a processor, a memory device, and an input / output interface.

[0048] In the following explanation, for simplicity, "anode gas" will be referred to as "fuel gas" or "fuel," and "anode gas supply pipe" will be referred to as "piping."

[0049] 3. <Example of a work vehicle system configuration> Next, an example of the system configuration of the work vehicle 100 will be described with reference to Figures 3 and 4. Figure 3 is a schematic block diagram showing an example of electrical connections and power transmission between components of the work vehicle 100 according to this disclosure. Figure 4 is a block diagram showing a more detailed configuration than the example in Figure 3. Figure 4 schematically shows the electrical signal paths (thin solid lines) and coolant paths (dotted lines) between components in the work vehicle 100.

[0050] First, with reference to Figure 3, examples of electrical connections and power transmission of components will be described. Electrical connections include both high-voltage and low-voltage systems. High-voltage electrical connections provide, for example, the power supply voltage for an inverter device. Low-voltage electrical connections provide, for example, the power supply voltage for electronic components that operate at relatively low voltages.

[0051] In the example shown in Figure 3, the work vehicle 100 comprises an FC module 10, an inverter device 72, a motor 70, a power transmission system 74, and a PTO shaft 76. The DC voltage of the power generated in the FC stack 11 of the FC module 10 is boosted by a boost circuit 40 and then supplied to the inverter device 72. The inverter device 72 converts the DC voltage to, for example, a three-phase AC voltage and supplies it to the motor 70. The inverter device 72 has a bridge circuit including a plurality of power transistors. The motor 70 has a rotating rotor and a stator having a plurality of coils electrically connected to the inverter device 72. The rotor is coupled to the output shaft 71, for example, via a reduction gear (speed reducer) or directly. The motor 70 rotates the output shaft 71 with torque and rotational speed controlled according to the waveform of the three-phase AC voltage from the inverter device 72.

[0052] The torque from the output shaft 71 of the motor 70 is transmitted to the power transmission system 74. The power transmission system 74 operates using the motor 70 as a power source and can drive the wheels 104R, 104F, and / or the PTO shaft 76 in Figure 1. Such a power transmission system 74 may have a structure similar to or identical to that of a power transmission system in a conventional tractor equipped with an internal combustion engine such as a diesel engine. For example, by adopting a power transmission system used in agricultural tractors, it is possible to reduce the design and manufacturing costs for producing an agricultural work vehicle 100 equipped with an FC power generation system. The power transmission system 74 includes a drive system power transmission mechanism that transmits power from the motor 70 to the left and right rear wheels 104R via a clutch, transmission, and rear wheel differential, etc., and a PTO system power transmission mechanism that transmits power from the motor 70 to the PTO shaft 76. The transmission case 102B in Figure 1 may be divided into a front case (transmission case) that houses the clutch and transmission, etc., and a rear case (differential gear case) that houses the rear differential gear, etc. The rear case is also called the rear axle case.

[0053] The work vehicle 100 is equipped with a secondary battery (battery pack) 80 that temporarily stores the electrical energy generated by the FC module 10. An example of the battery pack 80 is a lithium-ion battery pack. The battery pack 80 can supply power to the inverter device 72 at the required timing, either in cooperation with the FC module 10 or independently. Various battery packs used in passenger electric vehicles can be used as the battery pack 80.

[0054] In addition to the motor 70 and inverter device 72, the work vehicle 100 is equipped with various electrically operated electrical components (on-board electronic components). Examples of electrical components include electromagnetic valves such as the on / off valve 20, the cooling fan of the radiator device 34, the electric pump of the cooling compressor 85, and a temperature control device for heating or cooling the FC stack 11. Such a temperature control device includes an electric heater 86. DC-DC converters 81, 82 and a storage battery 83 for obtaining a power supply voltage suitable for the operation of these electrical components may also be included in the electrical components. Furthermore, various electronic components not shown (such as lamps and electric motors for hydraulic systems) may also be included in the electrical components. These electrical components may be similar to the electronic components installed in conventional agricultural tractors, for example.

[0055] In the example shown in Figure 3, the first DC-DC converter 81 is a circuit that steps down the voltage output from the boost circuit 40 of the FC module 10 to a first voltage, for example, 12 volts. The battery 83 is, for example, a lead-acid battery, and can store electrical energy at the voltage output from the first DC-DC converter 81. The battery 83 can be used as a power source for various electrical components, such as lamps.

[0056] The work vehicle 100 shown in Figure 3 is equipped not only with a first DC-DC converter 81 but also with a second DC-DC converter 82 as a voltage conversion circuit to step down the high voltage output by the FC module 10. The second DC-DC converter 82 is a circuit that steps down the voltage output from the boost circuit 40 of the FC module 10 (for example, several hundred volts) to a second voltage higher than the first voltage, for example, 24 volts. The cooling fan of the radiator unit 34 can operate with the voltage output from the second DC-DC converter 82, for example. Although the radiator unit 34 is shown as a single component in Figure 3, a single work vehicle 100 may be equipped with multiple radiator units 34. In addition, the electric pump of the cooling compressor 85 and the electric heater 86 can also operate with the voltage output from the second DC-DC converter 82.

[0057] The work vehicle 100 shown in Figure 3 is equipped with a temperature control device for cooling or heating the FC stack 11 included in the FC power generation system. Such a temperature control device requires a relatively large amount of power to operate. A relatively high voltage of 24 volts output by the second DC-DC converter 82 is supplied to this temperature control device. In this embodiment, the temperature control device includes a radiator device 34 for dissipating heat from the refrigerant used to cool the FC stack 11, and a relatively high voltage of 24 volts output by the second DC-DC converter 82 is supplied to the radiator device 34. The temperature control device includes a heater 86 for heating the FC stack 11. The relatively high voltage output by the second DC-DC converter 82 may also be supplied to the heater. The relatively high voltage output by the second DC-DC converter 82 may also be supplied to an air conditioning device, such as a cooling compressor 85.

[0058] The work vehicle 100 may also be equipped with a third voltage conversion circuit that converts the high voltage output by the FC module 10 into a third voltage higher than the second voltage. The third voltage is, for example, 48 volts. If the work vehicle 100 is equipped with other motors in addition to the motor 70, the third voltage may be used as a power source for such other motors, for example.

[0059] In agricultural work vehicles equipped with fuel cell power generation systems, in addition to electrical equipment necessary for agricultural work, electrical equipment necessary for the operation of the fuel cell power generation system is also installed, and therefore the appropriate voltage levels for each electrical equipment may differ. According to the embodiments of this disclosure, it becomes possible to supply an appropriate voltage level.

[0060] In the example shown in Figure 3, multiple fuel tanks 50 are housed within a single tank case 51. The fuel tanks 50 are connected to a filling port 52 into which fuel is supplied from the outside. This connection is made by piping 21 for carrying fuel gas. The fuel tanks 50 are also connected to the FC module 10 via piping 21 equipped with an on / off valve 20. When hydrogen is used as the fuel gas, these pipes 21 may be made of a material with high resistance to hydrogen embrittlement, such as austenitic stainless steel like SUS316L.

[0061] As will be described later, the tank case 51 is provided with a valve space 53, and various valves, including a pressure reducing valve, are arranged in this valve space 53. Through the various valves provided in the valve space 53, the piping 21 connects the fuel tank 50 and the FC module 10. Fuel gas, whose pressure has been reduced by the pressure reducing valve, flows through the piping 21 connecting the tank case 51 and the FC module 10. When the fuel gas is hydrogen gas, the fuel tank 50 may be filled with high-pressure hydrogen gas of, for example, 35 megapascals or more, but the hydrogen gas after passing through the pressure reducing valve may be reduced to, for example, about 2 atmospheres or less.

[0062] Next, refer to Figure 4. In addition to what is shown in Figure 3, Figure 4 shows multiple ECUs that communicate within the work vehicle 100, and user interface 1. Communication may be performed via CAN bus wiring, which functions as a path for electrical signals (thin solid lines). Figure 4 also shows a cooling system for achieving thermal management of the components. Specifically, the coolant path (dotted lines) is schematically shown.

[0063] As mentioned above, the first and second DC-DC converters 81 and 82 are each capable of outputting voltages of different magnitudes. These first and second DC-DC converters 81 and 82 are also provided with ECUs that control their respective voltage conversion circuits. These ECUs, like other ECUs, are supplied with a relatively low first voltage output by the first DC-DC converter 81.

[0064] In the example shown in Figure 4, the work vehicle 100 is equipped with a cooling system in which coolant is circulated by coolant pumps 31A and 31B. These coolant pumps 31A and 31B are located inside the FC module 10. The cooling system in this example includes a first radiator device 34A responsible for cooling the FC stack 11 and a second radiator device 34B responsible for cooling other electrical components. The cooling system has a flow path (first flow path) through which coolant flows between the FC stack 11 and the first radiator device 34A. The cooling system also has a flow path (second flow path) through which coolant flows between the electrical components, including the motor 70, and the second radiator device 34B. In the example shown in Figure 4, for example, a heater core 87 used for heating the cabin is provided, and the coolant flowing through the first radiator device 34A also flows through this heater core 87.

[0065] The user interface 1 includes an operating device 2, such as an accelerator pedal (or accelerator lever), and a main ECU 3 connected to the operating device 2. The main ECU 3 is connected to a main meter 4. The main meter 4 can display various parameters that identify the driving or operating status of the work vehicle 100. The user interface 1 further includes an FC system ECU 5 for controlling the FC power generation system. The FC system ECU 5 is connected to an FC meter 6. The FC meter 6 can display various parameters that identify the operating status of the FC power generation system.

[0066] The cells of the battery pack 80 are controlled by a battery management unit (BMU). The BMU includes circuits and a CPU (Central Processing Unit) that monitor the voltage of each battery cell, monitor for overcharging and over-discharging, and control cell balance. These circuits and the CPU may be mounted on a battery controller board.

[0067] 4. <Embodiment> Next, the basic configuration of an embodiment of the work vehicle according to this disclosure will be described with reference to Figures 5 to 7. Figure 5 is a schematic side view showing an example of the configuration of the work vehicle 200 in this embodiment. Figure 6A is a schematic side view showing an example of the arrangement of the main parts in the work vehicle 200, and Figure 6B is a plan view thereof. Figure 7 is a schematic diagram showing the mechanism supporting the fuel tank 50.

[0068] 4.1. Fixed Frame The work vehicle 200 in this embodiment includes an FC module 10, a fuel tank 50, a motor 70, a driver's seat 107, and a vehicle body 102. The work vehicle 200 has the same configuration as the work vehicle 100 described with reference to Figure 1.

[0069] In this embodiment, the fuel tank 50 is supported by a fixed frame 120. The fixed frame 120 is fixed to the vehicle body 102, straddling the driver's seat 107. In the work vehicle 200 of this embodiment, the configuration and function of the fixed frame 120 make it possible to stably support the fuel tank 50 above the driver's seat 107. As a result, the degree of freedom in arranging components such as the FC module 10 and motor 70 supported by the vehicle body 102 is increased. Furthermore, the need to significantly change the structure of conventional engine-driven tractors is reduced. These factors contribute to a reduction in design and manufacturing costs.

[0070] The following describes an example configuration of the fixed frame 120.

[0071] In this embodiment, the fixed frame 120 is a long-axis structure such as a pipe fixed to the vehicle body 102. As shown in Figure 6A, the fixed frame 120 has a front part 120A, an intermediate part 120B, and a rear part 120C. The front part 120A has a curved shape and is connected to the intermediate part 120B. The intermediate part 120B has a shape that extends linearly in the front-rear direction and is connected to the rear part 120C. The rear part 120C has a shape that extends linearly in the vertical direction. Note that the shape of the fixed frame 120 shown is merely an example, and the shape of the fixed frame 120 is not limited to this example.

[0072] In this embodiment, the vehicle body 102 has a front frame 102A that rotatably supports the front wheel 104F and a transmission case 102B that rotatably supports the rear wheel 104R. As shown in Figure 6A, one end (front end) 128 of the fixed frame 120 is fixed to the front frame 102A. The other end (rear end) 129 of the fixed frame 120 is fixed to the transmission case 102B. These fixations can be made by appropriate methods such as welding or bolting, depending on the material of the fixed frame 120. The fixed frame 120 may be formed from, for example, metal, synthetic resin, carbon fiber, or composite material such as carbon fiber reinforced plastic or glass fiber reinforced plastic. The transmission case 102B includes a rear axle case, and the rear end 129 of the fixed frame 120 may be fixed to the rear axle case. If the fixed frame 120 is made of metal, part or all of its surface may be covered with synthetic resin.

[0073] The fixed frame 120 is required to have sufficient rigidity to support the fuel tank 50. When the work vehicle 200 travels over uneven ground, the fuel tank 50 supported by the fixed frame 120 may vibrate vertically or horizontally. Due to the elastic deformation of the fixed frame 120, part or all of the fixed frame 120 will bend appropriately, thereby mitigating the impact on the fuel tank 50. To achieve this impact mitigation effect, it is effective for the front part 120A of the fixed frame 120 to have a curved shape and to allow deformation within a predetermined range. Part or all of the rear part 120C of the fixed frame 120 may have a curved or inclined shape.

[0074] The external shape of the cross-section perpendicular to the long axis of the fixed frame 120 is, for example, a circle or an ellipse, but is not limited thereto. The external shape of the cross-section may be a quadrilateral or other polygon. If the fixed frame 120 has a roughly cylindrical or columnar shape, its outer diameter is, for example, in the range of 10 mm to 100 mm. The inner diameter may be between 0% and 90% of the outer diameter.

[0075] As shown in Figure 5, the work vehicle 200 is equipped with a cabin 105 surrounding a driver's seat 107 between the body 102 and the fixed frame 120. The driver's seat 107 is located at the rear of the interior of the cabin 105 (referred to as the "cabin interior"). In front of the driver's seat 107 is a steering handle (steering wheel) 106 for changing the direction of the front wheels 104F, for example. The cabin 105 has a cabin frame that constitutes the framework. A roof 109 is provided on top of the cabin frame. The cabin frame in this embodiment is a four-pillar type. The cabin 105 is supported by the transmission case 102B of the body 102, for example, via vibration-damping mounts. Interface 1, which was described with reference to Figure 4, is provided inside the cabin 105. Since the cabin 105 does not directly support the fuel tank 50, it does not need to be specially strengthened, and a cabin that has been used in conventional tractors can be used.

[0076] The intermediate section 120B of the fixed frame 120 extends in the longitudinal direction along the roof 109 of the cabin 105 and functions as a support for the fuel tank 50. The fuel tank 50 is supported by the intermediate section 120B of the fixed frame 120 above the roof 109 of the cabin 105.

[0077] Next, refer to Figure 6B. In this embodiment, the fixed frame 120 includes not one frame, but two frames located on the left and right sides of the work vehicle 200. In the plan view of Figure 6B, the left and right fixed frames 120 extend parallel to the front-rear direction of the work vehicle 200. The two fixed frames 120 are positioned to avoid the central field of view of the operator seated in the driver's seat 107 and looking forward. The number of fixed frames 120 may be one or three or more. It is desirable that the fixed frames 120 are positioned to avoid the central field of view of the operator seated in the driver's seat 107 and looking forward, and to support the fuel tank 50 in a balanced manner. From this viewpoint, it is desirable that the number of fixed frames 120 be even.

[0078] As shown in Figure 6B, in a top view looking down, it is not necessary for each fixed frame 120 to pass directly above the driver's seat. In this disclosure, when a fixed frame is said to be fixed to the vehicle body "spanning the driver's seat," it means that, as shown in Figure 6A, in a side view, a portion of the fixed frame fixed to the vehicle body extends along the longitudinal direction above the driver's seat 107 or above the cabin 105. In the example in Figure 6B, the two fixed frames 120 are parallel to each other, but the distance between the fixed frames 120 does not need to be constant along the longitudinal direction and may vary.

[0079] The work vehicle 200 is equipped with a mounting platform 51A that connects the left frame 120 and the right frame 120. The fuel tank 50 may be placed on the mounting platform 51A. If there are multiple fuel tanks 50, the multiple fuel tanks 50 may be housed in a fuel tank module. The fuel tank module includes a tank case 51 that houses the multiple fuel tanks 50 (Figure 5). The left and right fixed frames 120 may be connected to each other by members other than the mounting platform 51A.

[0080] A coupling device 108 is provided at the rear end of the transmission case 102B, which is the rear of the vehicle body 102. The coupling device 108 includes, for example, a three-point support device (also referred to as a "three-point link" or "three-point hitch"), a PTO shaft, a universal joint, and a communication cable. The coupling device 108 allows the implement 190 to be attached to and detached from the work vehicle 200. The coupling device 108 can change the position or orientation of the implement 190 by raising and lowering the three-point link, for example, by a hydraulic device. Power can also be supplied from the work vehicle 200 to the implement 190 via the universal joint. The work vehicle 200 can pull the implement 190 and cause the implement 190 to perform a predetermined task (agricultural work). The coupling device 108 may also be provided at the front of the vehicle body 102. In that case, the implement 190 can be connected to the front of the work vehicle 200.

[0081] Next, with reference to Figure 7, an example of a configuration in which the fuel tank 50 is supported by a fixed frame 120 will be described.

[0082] In the example shown in Figure 7, the mounting base 51A for the fuel tank 50 is fixed to the intermediate section 120B of the fixed frame 120. This fixing can be achieved, for example, by a connector 127 such as a pipe mounting bracket. The fuel tank 50 is fixed to the mounting base 51A by, for example, a fixing belt 56. A cover 51B is attached to the mounting base 51A so as to cover the fuel tank 50 and is removable or openable. In this example, the tank case 51 consists of the mounting base 51A and the cover 51B. The tank case 51 functions as part of at least one housing that contains the FC module 10 and the fuel tank 50.

[0083] In this embodiment, the cover 51B has a curved portion 51C that connects from the top portion 51T to the surrounding side portion 51S. The height of the cover 51B is highest at the top portion 51T, and the height of the curved portion 51C decreases as it approaches the side portion 51S. By adopting a cover 51B of this shape, it is possible to suppress the accumulation of rain on the cover 51B of the tank case 51 and to make it easier to remove snow accumulated on the tank case 51. The tank case 51 may be provided with an opening for exhausting fuel gas that has leaked inside to the outside. It is preferable that such an opening be covered with a member such as a lid to prevent rain, dust, etc. from entering the inside of the tank case 51. The tank case 51 may be formed from metal, synthetic resin, carbon fiber, or composite material such as carbon fiber reinforced plastic or glass fiber reinforced plastic.

[0084] Inside the tank case 51, the fuel tank 50 is connected to piping 21 for carrying fuel gas via valves 57, such as a pressure reducing valve and a solenoid valve. The piping 21 inside the tank case 51 is connected to piping outside the tank case 51, for example, through an opening provided in the mounting base 51A. In the example in Figure 7, a portion of the piping 21 outside the tank case 51 is located inside the intermediate section 120B of the fixed frame 120. In other words, a portion of the piping 21 connecting the fuel tank 50 and the FC module 10 is located inside the fixed frame 120. The piping 21 connecting the tank case 51 and the FC module 10 is configured to carry fuel that has been depressurized by a pressure reducing valve. Wiring cables are connected to the valves 57, such as a solenoid valve. Some or all of these wiring cables may pass inside the fixed frame 120.

[0085] The piping 21 or wiring cables may be routed along the outer surface of the fixing frame 120 rather than inside the fixing frame 120. However, it is preferable to route them inside the fixing frame 120 so that the rigid fixing frame 120 can effectively protect the piping 21 and wiring cables.

[0086] The fixed frame 120 does not need to be fixed to the roof 109 of the cabin 105. As shown in Figure 7, there may be a gap between the roof 109 of the cabin 105 and the intermediate portion 120B of the fixed frame 120. When the work vehicle 200 is traveling on uneven ground, the vertical vibration of the cabin 105 and the vertical vibration of the tank case 51 supported by the fixed frame 120 do not need to match in amplitude and frequency. In the example in Figure 7, a damper 54 is provided between the roof 109 and the mounting platform 51A. Such a damper 54 suppresses collision of the mounting platform 51A with the roof 109 even when the work vehicle 200 moves up and down significantly.

[0087] In this embodiment, the rear portion 120C of the fixed frame 120 supports the mounting base 51A in a state where it extends vertically (Figures 5 and 6A). If the rear portion 120C of the fixed frame 120 is made of a material such as metal that does not easily expand or contract in the longitudinal direction, the rear portion 120C will function to suppress the vertical movement of the mounting base 51A relative to the vehicle body 102. On the other hand, if the cabin 105 is supported by the vehicle body 102 via a vibration-damping mount 105B, the vibration of the cabin 105 relative to the vehicle body 102 may behave differently from the vibration of the mounting base 51A relative to the vehicle body 102. If a damper 54 is provided between the roof 109 and the mounting base 51A, it becomes possible to control the coupled vibration of the cabin 105 and the fuel tank 50 by adjusting the damping ratio of the damper 54. The type, number, and position of the damper 54 may be determined considering the size and weight of the tank case 51, etc. Alternatively, the cabin 105 and the mounting base 51A may be connected by an elastic member such as a spring or rubber, instead of, or together with, the damper 54. The damper 54 and / or elastic member may be positioned to connect the cabin 105 to the intermediate portion 120B of the fixed frame 120, rather than to the mounting base 51A.

[0088] Unlike this embodiment, if the fuel tank 50 is firmly fixed to the cabin 105 by means of welding or connecting fittings such as flange bolts, the cabin 105 and the fuel tank 50 will move or vibrate together as a single unit during driving. In contrast, in this embodiment, a certain degree of freedom of movement is allowed between the cabin 105 and the fuel tank 50, making it possible to separate the vibration modes of the cabin 105 and the vibration modes of the fuel tank 50. This, for example, provides a soundproofing effect inside the cabin.

[0089] As mentioned above, if a portion of the piping 21 is provided inside the fixed frame 120, a fuel filling port connected to the piping 21 may also be provided on the fixed frame 120. (Details of the fuel filling port 52 (Figures 3 and 4) will be described later.)

[0090] 4.2. Fuel Tank Module Next, an example of a fuel tank module configuration will be described with reference to Figure 8. Figure 8 shows the mutually orthogonal X and Y axes for reference.

[0091] The fuel tank module 55 in the example shown in Figure 8 includes a plurality of fuel tanks 50, a valve system 58 connected to the plurality of fuel tanks 50, and a tank case 51 that houses the plurality of fuel tanks 50 and the valve system 58.

[0092] The valve system 58 includes on-off valves and pressure reducing valves located within the tank case 51. The valve system 58 housed in the tank case 51 may also further include check valves, filters, safety valves, pressure sensors, and relief pipes. These components of the valve system 58 are connected by high-pressure or low-pressure piping.

[0093] The tank case 51 has a bottom plate that extends along a plane (XY plane) defined by the X-axis direction (first direction) and the Y-axis direction (second direction), and multiple fuel tanks 50 are placed on the bottom plate. In this embodiment, this bottom plate also serves as a mounting base 51A. The mounting base 51A does not need to be a flat plate, and may have ridges or grooves to increase its strength. The mounting base 51A may also have protrusions, recesses, and / or openings for fixing the fuel tanks 50, covers 51B, and other components such as valves.

[0094] Each of the multiple fuel tanks 50 in this embodiment is a high-pressure hydrogen tank having a cylindrical portion extending in the X-axis direction. The outer diameter of the cylindrical portion may be, for example, about 300 mm. An example of a fuel tank 50 is a resin-made high-pressure hydrogen tank, which may be formed from a multilayer structure consisting of a resin liner, carbon fiber reinforced plastic, and glass fiber reinforced plastic.

[0095] In this example, the multiple fuel tanks 50 include a first fuel tank 50A having a first length L1 in the X-axis direction, a second fuel tank 50B having a second length L2 in the X-axis direction that is shorter than the first length L1, and a third fuel tank 50C having a third length L3 in the X-axis direction that is shorter than the first length L1. In other embodiments of this disclosure, the third fuel tank 50C is not required, and other fuel tanks may be included. The number of fuel tanks 50 in a single fuel tank module 55 is not limited to three, but may be multiple. Also, in the example in Figure 8, the third length L3 is equal to the second length L2, but the third length L3 may be different from the second length L2.

[0096] The first fuel tank 50A, the second fuel tank 50B, and the third fuel tank 50C are arranged (aligned) in the Y-axis direction perpendicular to the X-axis direction. At least a portion of the valve system 58 is located within the tank case 51 in the space formed between the second fuel tank 50B and the tank case 51. At least another portion of the valve system 58 is located within the tank case 51 in the space formed between the third fuel tank 50C and the tank case 51. In other words, the valve system 58 is located in the valve space 53 in the space from the second fuel tank 50B and the third fuel tank 50C to the tank case 51. The sizes of L1-L2 and L1-L3 are determined based on the size of the space required for the valve space 53. In this embodiment, for example, if L1 = approximately 700 mm, then L1-L2 = L1-L3 = 100 mm or more and 200 mm or less.

[0097] In this way, by housing fuel tanks 50 of different lengths within the tank case 51, a space suitable for housing components can be formed within the tank case 51, and this space can be used as a valve space 53. By arranging several valves, including, for example, an on-off valve and a pressure reducing valve, in the valve space 53, the functionality of the fuel tank module 55 can be enhanced. Specifically, the pressure reducing valve inside the tank case 51 can reduce the fuel pressure from, for example, 35 megapascals to a few atmospheres before it is taken out of the tank case 51. As a result, there is no longer a need to use expensive piping for high-pressure hydrogen gas as the piping 21 for connecting the tank case 51 and the FC module 10.

[0098] Next, with reference to Figure 8, an example of a configuration for filling the fuel tank 50 of such a fuel tank module 55 with fuel will be described.

[0099] In the example shown in Figure 8, the fuel filling device 90 comprises a fuel storage unit 91, a shut-off valve 92, a regulator 93, a cooling unit 94, and a dispenser nozzle 95. The fuel filling device 90 may be installed at a specific site or may be mounted on a moving vehicle such as a truck and function as a mobile station. The dispenser nozzle 95 of the fuel filling device 90 is connected to the cooling unit 94 via a flexible fuel hose. The worker performing the fuel filling inserts the dispenser nozzle 95 into the fuel filling port 52 of the work vehicle 200, and then the filling of fuel (high-pressure hydrogen gas) begins.

[0100] The fuel filling port 52 of the work vehicle 200 has a receptacle 96 that receives fuel from the dispenser nozzle 95 of the fuel filling device 90. The receptacle 96 is inserted into an opening at the tip of the dispenser nozzle 95 when the dispenser nozzle 95 is inserted into the fuel filling port 52. The fuel injected from the dispenser nozzle 95 into the receptacle 96 is supplied to fuel tanks 50A, 50B, and 50C located in the tank case 51 of the fuel tank module 55 through a pipe 21 equipped with a check valve 97. The fuel tanks 50A, 50B, and 50C are connected to the pipe 21 via solenoid valves 57A, 57B, and 57C, respectively.

[0101] By selectively opening the solenoid valves 57A, 57B, and 57C, fuel is supplied from the fuel filling device 90 to one of the corresponding fuel tanks 50A, 50B, or 50C.

[0102] 4.3. Fuel gas sensor In this embodiment, the FC module 10 and the fuel tank 50 are housed in at least one "container". Figure 9A schematically shows the flow of leaked fuel (hydrogen) gas inside the front housing 110 and tank case 51, which function as such a containment. In Figure 9A, the flow of leaked fuel gas is schematically represented by dotted arrows. Such fuel gas leaks can originate from the FC module 10, the fuel tank 50, the valve system 58, and the piping 21, etc. In the example in Figure 9A, the piping 21 connecting the fuel tank 50 and the FC module 10 is inserted into the front housing 110 through the inside of the fixed frame 120.

[0103] The work vehicle 200 in this embodiment is equipped with at least one fuel gas sensor located within its housing. In this embodiment, the fuel gas is hydrogen gas, so examples of fuel gas sensors may include hydrogen gas sensors that operate in various ways, such as catalytic combustion, gaseous heat conduction, solid electrochemical, and semiconductor types. When the fuel gas sensor detects a fuel gas leak, depending on the concentration level of the leaked fuel gas, the system may perform actions such as notifying or warning the driver, or implementing fail-safe control or shutdown of the FC power generation system.

[0104] In this embodiment, the containment, namely the front housing 110 and the tank case 51, each has a shape and structure that controls the spread of hydrogen gas leaking inside them into the atmosphere, thereby facilitating the detection of hydrogen gas. Specifically, the upper surface 110U of the front housing 110 has a shape that gradually or in stages rises from the front end of the work vehicle 200 toward the rear. Since hydrogen gas leaking inside the front housing 110 is lighter than air, it flows toward the rear along the upper surface 110U of the front housing 110 and approaches the front surface 105F of the cabin 105. In addition, some of the fuel gas leaking from the piping 21 inside the front housing 110, or from the connections between the FC module 10 and the piping 21, may rise along the front surface 105F of the cabin 105.

[0105] In this embodiment, the width of the front housing 110 is designed to be narrower than the wheel spacing of the front wheels 104F. This differs from the case of a passenger car, where the hood covers the left and right front wheels, and the width of the hood is wider than the wheel spacing of the front wheels. By making the width of the front housing 110 narrower than the wheel spacing of the front wheels 104F, the volume of the front housing 110 can be relatively reduced. By reducing the volume of the front housing 110, it becomes possible to easily detect leaked hydrogen gas by the fuel gas sensor before it is diluted.

[0106] As described above, in this embodiment, the height of the tank case 51 is highest at the top surface 51T, and the height of the curved surface 51C decreases as it approaches the side surface 51S. For this reason, hydrogen gas that leaks inside the tank case 51 tends to accumulate in the upper part of the tank case 51, rather than in the peripheral area.

[0107] Furthermore, in this embodiment, the tank case 51 is located behind the front housing 110 and at a higher position than the front housing 110. Therefore, if the front housing 110 and the tank case 51 are connected by piping 21, hydrogen gas leaking from inside the front housing 110 may enter the interior of the tank case 51 through some route. The tank case 51 is located at the highest position within the "container" of the FC power generation system. Therefore, if the containment forms a connected space, hydrogen gas leaking from inside the containment tends to accumulate near the tank case 51, or more specifically, near the upper surface 51T of the tank case 51, which is the highest part of the containment.

[0108] In the example shown in Figure 9A, the fuel gas sensor includes a first sensor 45 located inside the front housing 110 and a second sensor 46 located inside the tank case. The first sensor 45 is located inside the front housing 110 in a relatively high area, i.e., an area where fuel gases accumulate. Specifically, the first sensor 45 is located inside the front housing 110 in an area where the front surface 105F of the cabin 105 and the upper surface 110U of the front housing 110 are in close proximity. More specifically, as shown in Figure 9B, the first sensor 45 is located behind the FC module 10 and in a space formed by being surrounded on three sides 110L, 110R and the upper surface 110U of the front housing 110. The first sensor 45 is also located above the FC module 10.

[0109] Furthermore, the second sensor 46 is located inside the tank case 51 at a higher position than the valve system 58, preferably below the upper surface 51T of the tank case 51. The second sensor 46 is located at a higher position than the first sensor 45 and functions as the highest-located fuel gas sensor in the work vehicle 200.

[0110] 4.4. Radiator System Next, the configuration of the radiator device in this embodiment will be described with reference to Figures 10 and 11. Figures 10 and 11 are schematic side views and plan views, respectively, showing examples of the arrangement of the radiator device in this embodiment.

[0111] As described above, the work vehicle 200 in this embodiment is equipped with a cooling system in which coolant is circulated by coolant pumps 31A and 31B shown in Figure 4. The work vehicle 200 also includes a first radiator device 34A located on one side (rear) of the FC module 10 and a second radiator device 34B located on the other side (front) of the FC module 10, as shown in Figures 10 and 11.

[0112] The first radiator unit 34A is connected to a flow path (first flow path) for cooling the FC stack 11 (see Figure 4) included in the FC module 10. On the other hand, the second radiator unit 34B is connected to a flow path (second flow path) for cooling electrical components including the motor 70. Thus, the cooling system in the work vehicle 200 of this embodiment includes a first radiator unit 34A responsible for cooling the FC stack 11 and a second radiator unit 34B responsible for cooling other electrical components. It is desirable that the cooling capacity for the FC stack 11 be increased to increase the cooling capacity for the other electrical components. To increase the cooling capacity of the radiator unit, it is necessary to enlarge the front surface area of ​​the radiator unit and increase the area (core size) in which the core portion of the heat exchanger is in contact with the air. For this reason, in this embodiment, the front surface area of ​​the first radiator unit 34A is made larger than the front surface area of ​​the second radiator unit 34B. Specifically, as shown in Figure 11, the width W1 of the first radiator unit 34A is greater than the width W2 of the second radiator unit 34B. In this embodiment, the width W2 of the second radiator unit 34B is smaller than the width W0 of the FC module 10, and the width W1 of the first radiator unit 34A is larger than the width W0 of the FC module 10.

[0113] By positioning the first radiator device 34A at the rear of the FC module 10, the following effects can be achieved.

[0114] First, it becomes possible to make the height and width of the front portion of the front housing 110 smaller than the height and width of the rear portion. Specifically, the front housing 110 in this embodiment has a first portion 110T1 located on the rear side and a second portion 110T2 located on the front side, with the height and width of the second portion 110T2 being smaller than the height and width of the first portion 110T1. Conversely, if a large first radiator device 34A is placed in front of the FC module 10, or if both the first and second radiator devices 34A and 34B are placed in front of the FC module 10, it becomes necessary to increase the width of the second portion 110T2 of the front housing 110. However, if the width of the front housing 110 is made greater than the distance between the left and right front wheels, and the front housing 110 covers the front wheels 104F, the front housing 110 will obstruct the view of the position and orientation of the front wheels 104F when the operator seated in the driver's seat 107 looks forward, making it difficult to accurately steer along farm roads or furrows, for example.

[0115] In contrast, according to this embodiment, since there is no need to enlarge the width of the second portion 110T2 of the front housing 110, there is no problem of the field of view being narrowed by the enlarged front housing 110 when the operator seated in the driver's seat looks forward.

[0116] The first radiator unit 34A can have a width W1 and height T1 of sufficient size by enlarging the first portion 110T1 of the front housing 110 to the required extent. Here, the height difference T1-T2 between the two radiator units 34A and 34B is, for example, in the range of 10 mm to 300 mm, and the width difference W1-W2 is, for example, in the range of 20 mm to 500 mm.

[0117] Furthermore, by arranging the two radiator units 34A and 34B on opposite sides of the FC module 10, the problem of thermal interference between the two radiator units 34A and 34B is also solved.

[0118] The front housing 110 preferably has at least one opening for introducing airflow to the first radiator unit 34A and / or the second radiator unit 34B. Part of such an opening can be realized by a gap formed between the first portion 110T1 and the second portion 110T2 of the front housing 110. Such a gap can be formed by making the height and width of at least a portion of the front end of the first portion 110T1 of the front housing 110 greater than the height and width of the rear end of the second portion 110T2.

[0119] The FC module 10 is preferably enclosed by a housing having sides and a top surface that guide the airflow from front to rear. By adopting such a configuration, it is possible to direct a sufficient airflow to the first radiator device 34A located at the rear of the FC module 10, thereby increasing the efficiency of heat exchange in the first radiator device 34A.

[0120] In this embodiment, as shown in Figure 10, the first radiator unit 34A is fixed to the front frame 102A via a support portion 34C, and the upper end (height T1) of the first radiator unit 34A is higher than the upper end (height T2) of the second radiator unit 34B. Specifically, the upper end (height T1) of the first radiator unit 34A is higher than the height T0 of the FC module 10, and the upper end (height T2) of the second radiator unit 34B is lower than the height T0 of the FC module 10. By adopting this configuration, the air introduced into the front housing 110 of the moving work vehicle 200 can flow smoothly in the rearward direction within the front housing 110, and heat exchange of the coolant by the first radiator unit 34A as well as the second radiator unit 34B can be properly performed.

[0121] Furthermore, the lower end of the first radiator device 34A is lifted by the support portion 34C. By utilizing the support portion 34C, it becomes possible to position the first radiator device 34A above the motor 70 (Figure 5).

[0122] Furthermore, the front housing 110 is provided with a number of openings or gaps as needed. Airflow can be formed by using these openings or gaps as air inlets and outlets.

[0123] 5. <Examples> 5.1. Opening and closing the hood Hereinafter, an agricultural tractor, which is an embodiment of the work vehicle of this disclosure, will be described with reference to Figures 12 to 16, and, as necessary, to Figures 1 to 11. Figures 12, 13, 14, 15, and 16 are perspective views, side views, top views, front views, and rear views of the agricultural tractor in the embodiment of this disclosure, respectively.

[0124] The basic configuration of the agricultural tractor according to this embodiment is the same as that of the work vehicle according to the previously described embodiment. The differences between the embodiment and the example will be described below. In the drawings, corresponding components between the embodiment and the example are denoted by the same reference numerals.

[0125] As shown in Figure 13, the agricultural tractor 300 in this embodiment includes a fixed frame 120 that straddles the driver's seat 107 and is fixed to the vehicle body 102, and supports a fuel tank module 55 having a fuel tank 50, and a front housing 110 that covers the fuel cell module 10. The front housing 110 is openable and closable. Specifically, the front housing 111 has a fixed housing portion 111 fixed to the vehicle body 102 and a movable housing portion 112 that is openable and closable and supported by the vehicle body 102 or the fixed housing portion 111. A specific example of the configuration of the front housing 110 will be described later.

[0126] In this embodiment as well, the fixed frame 120 includes a left frame and a right frame. One end of each fixed frame 120 is fixed to the front frame 102A at a connection position 128 that is in front of the front axle 104FX of the front wheel 104F. As shown in Figure 14, in a top view looking down from above, the front housing 110 is located between the left frame and the right frame and protrudes in front of the connection position 128.

[0127] The agricultural tractor 300 of this embodiment is equipped with a connecting bar 114 that connects the left frame and the right frame. The connecting bar 114 in this embodiment includes a plurality of bars 114A, 114B that are positioned at different heights. As shown in the plan view of Figure 14, the connecting bars 114A, 114B are connected to the left and right frames 120 at a position in front of the connection point 128 of the fixed frame 120. The connecting bar 114 has rigidity or mechanical strength that attempts to maintain a constant distance between the left and right fixed frames 120 even when an external force is applied to one or both of the left and right fixed frames 120. The connecting bar 114 is preferably formed from metal. The connecting bar 114 contributes to increasing the overall structural strength of the fixed frame 120.

[0128] The agricultural tractor 300 has left and right rearview mirrors 105M and turn signals / side marker lights 105L mounted on the cabin 105, as shown in Figure 12. Figure 12 also shows a lead-acid battery 83 and a step 84 for getting in and out of the cabin 105. The front of the front housing 110 is equipped with a headlamp 130 and work lights 132. The roof 109 is also equipped with multiple work lights, and various sensor devices such as laser sensors for obstacle detection may also be provided. The location of these devices and components on a typical agricultural tractor is not limited to the examples shown.

[0129] As shown in Figures 15 and 16, in the agricultural tractor 300 of this embodiment, a fuel tank module 55 is located above the cabin 105, and the left and right fixed frames 120 that support this fuel tank module 55 straddle the cabin 105. Also, as shown in Figure 16, the portion of the fixed frame 120 located behind the cabin 105 extends vertically between the left and right rear fenders 116. The rear end of each fixed frame 120 is fixed to the rear axle case (rear axle) 104RC.

[0130] The following describes an example configuration of the movable housing section 112. Figure 17 is a side view of the agricultural tractor 300 in this embodiment with the front housing 110 in the open position. The front housing 110, specifically the movable housing section 112, is configured to rotate around a pivot point located in front of the axle of the front wheel 104F (front axle 104FX: see Figure 12). The position of the pivot point is defined by a rotation support device such as a hinge. In the example of Figure 17, the lower front end of the movable housing section 112 is connected to the front frame 102A by a rotation support device. The position of such a pivot point is not limited to this example. As shown in Figure 18, the movable housing section 112 may be configured to rotate around a pivot point located behind the axle position of the front wheel 104F. In the example of Figure 18, a rotation support member such as a hinge is provided on the fixed housing section 111.

[0131] In this embodiment, the movable housing portion 112 is configured to house the fuel cell module 10. In contrast, the fixed housing portion 111 houses the equipment included in the fuel cell power generation system, specifically the radiator device 34A that dissipates heat from the coolant for the fuel cell.

[0132] An important point in this embodiment is that the fixed frame 120 has a shape that prevents it from interfering with the front housing 110 (specifically, the movable housing portion 112) when its position or orientation changes from a closed state to an open state. In other words, in the fixed frame 120 located in front of the cabin 105, the distance (spacing) W11 between one side of the fixed frame 120 and the other side is set to be greater than the maximum width W12 of the movable housing portion 112.

[0133] The position and shape of the connecting bar 114 in this embodiment will be described with reference to Figures 19 and 20. Figure 19 is a schematic side view showing the range of motion of the movable housing 112 in a configuration where the rotation axis AR is located at the front of the movable housing 112. In contrast, Figure 20 is a schematic side view showing the range of motion of the movable housing 112 in a configuration where the rotation axis AR is located at the rear of the movable housing 112. In Figures 19 and 20, the movable housing 112 shown by a solid line is in the "closed state," and the movable housing 112 shown by a dotted line is in the "open state." In each figure, the position of the rotation axis AR perpendicular to the plane of the paper is indicated by a black dot. Furthermore, the rotational movement of the movable housing 112 when it changes from the "closed state" to the "open state" is schematically shown by a solid arrow.

[0134] The connecting bars 114 that connect the left and right fixed frames 120 are positioned outside the range of motion of the movable housing portion 112. In the example shown in Figure 19, the connecting bars 114 (connecting bars 114A, 114B) are positioned in front of the movable housing portion 112 when the front housing 110 is in the "open state," and are shaped so as not to interfere with the movable housing portion 112.

[0135] In this embodiment, the connecting bar 114 has a shape that protrudes convexly in the forward direction in the plan view of Figure 14. Therefore, if the movable housing portion 112 has a curved shape that is highest at the center of the upper surface, the connecting bar 114 can efficiently form a space that appropriately receives the movable housing portion 112 when it is in the "open state".

[0136] As shown in Figures 14, 19, and 20, the connecting bar 114A, which is in a relatively higher position, protrudes further forward than the connecting bar 114B, which is in a relatively lower position. This makes it possible to increase the angle (movement angle) that defines the range of motion of the movable housing 112 in the configuration example shown in Figure 19. Also, in the configuration example shown in Figure 20, because the position of the rotation axis AR is high, the foremost point of the range of motion of the movable housing 112 also rises to a relatively high position, but it becomes possible to appropriately isolate the upper connecting bar 114A from such a range of motion.

[0137] In this embodiment, the two connecting bars 114A and 114B also serve to protect the front housing 110 by preventing it from colliding with an obstacle when the front of the front housing 110 approaches an obstacle, for example, while driving. A third connecting bar may be provided at a position other than the movable range of the movable housing portion 112 shown in Figures 19 and 20.

[0138] In this embodiment, since the fixed housing portion 111 is located behind the movable housing portion 112, the movable housing portion 112 is positioned forward by the length of the fixed housing portion 111 in the front-rear direction of the vehicle body 102. If the two connecting bars 114A and 114B in this embodiment are used as the front frame 102A and movable housing portion 112 in this embodiment without changing the length of the front frame and front housing in an existing agricultural tractor, for example, the position of the tip of the movable housing portion 112 relative to the tip position of the front frame 102A will be advanced by the length of the fixed housing portion 111. Therefore, in such a case, it is particularly desirable to adopt the above configuration in order to prevent the connecting bar 114 from interfering with the movable housing portion 112. Furthermore, it is preferable that the position where the fixed frame 120 and the connecting bars 114A and 114B are connected and fixed is also relatively forward. In this example, the fixed frame 120 is curved to protrude forward, as shown in Figures 19 and 20, for example. This has the advantage of making it easier to position the connecting bar 114 so as not to interfere with the movable housing portion 112.

[0139] Next, an example of the configuration of the fixed housing portion 111 in this embodiment will be described with reference to Figures 21 to 23. Figures 21 and 22 are a perspective view and a side view of the fixed housing portion 111 in this embodiment, respectively. Figure 23 is a diagram showing the arrangement relationship between the fixed housing portion 111 and the handle stay cover 106X. Note that the steering handle (steering wheel) is omitted in Figure 23.

[0140] The fixed housing portion 111 houses components (in this example, the radiator unit 34A) that are too large to be accommodated by the movable housing portion 112. Preferably, the maximum width inside the fixed housing portion 111 is greater than the maximum width inside the movable housing portion 112. The fixed housing portion 111 is located behind the movable housing portion 112. If the radiator unit 34A is housed within the fixed housing portion 111, a cooling fan for the radiator unit 34A may also be housed within the fixed housing portion 111. Such a cooling fan may be positioned opposite the rear or front of the radiator unit 34A.

[0141] In this embodiment, the fixed housing portion 111 has a top surface portion 111A, a pair of side portions 111B and 111C, and a front wall 111E. The front wall 111E is located on the side of the movable housing portion 112 and has an opening 111D that communicates with the interior of the movable housing portion 112 when it is closed. Through this opening 111D, components located inside the fixed housing portion 111 and components located inside the movable housing portion 112 can be connected by piping, coolant flow paths, electrical cables, etc. The front wall 111E faces the rear end of the movable housing portion 112 when it is closed. Therefore, the opening 111D of the fixed housing portion 111 is blocked by the movable housing portion 112 when it is closed. However, a gap may exist between the movable housing portion 112 when it is closed and the fixed housing portion 111. Such a gap allows for air circulation.

[0142] As shown in Figure 22, a steering wheel stay cover 106X, on which the steering wheel 106 is mounted, is located in front of the driver's seat 107. The fixed housing portion 111 is located in front of this steering wheel stay cover 106X. Figure 22 shows the length "L" of the fixed housing portion 111 in the longitudinal direction of the vehicle body 102. This fixed housing portion 111, having such a length L, is located between the movable housing portion 112 and the cabin 105. As mentioned above, it can be said that the tip of the movable housing portion 112 is shifted forward by this length L.

[0143] As shown in Figure 23, when viewed from the driver's seat inside the cabin 105, the fixed housing 111 is located beyond the handlebar cover 106X. The cabin 105 has glass 105W on all four sides surrounding the driver's seat. The glass 105W is located between the inside of the cabin 105 and the fixed housing 111. The width of the fixed housing 111 is wider than the width of the handlebar cover 106X, but the height of the fixed housing 111 is lower than the height of the handlebar cover 106X. The handlebar cover 106X is equipped with a display 106D for displaying various information, including vehicle speed. The height of the fixed housing 111 may be designed not to be greater than the height of the handlebar cover 106X so that it does not obstruct the forward view of the operator who is alternately looking at the front of the agricultural tractor 300 and the display 106D.

[0144] In this embodiment, instead of the entire front housing 110 opening and closing, a portion of the front housing 110 functions as a fixed housing portion 111, and the remaining portion functions as a movable housing portion 112. This reduces the difficulty of opening and closing operations that may arise when the front housing 110 is enlarged, making maintenance and other tasks easier for the operator. In particular, if there are parts that are too large to fit in a typical-sized front housing, instead of enlarging the entire opening and closing front housing, housing such large parts in the fixed housing portion has the advantage of avoiding the need to enlarge the size of the opening and closing portion (movable housing portion). While this advantage is effective for work vehicles equipped with fuel cell power generation systems, it is also effective for agricultural tractors equipped with other drive systems. In other words, the effect of dividing the so-called bonnet into multiple parts and making a portion of it openable and closable is also effective for agricultural tractors equipped with internal combustion engines or battery-powered motors.

[0145] 5.2. Inverter Unit Layout Figure 24 is a perspective view showing the arrangement of the inverter device 72 in this embodiment. The front housing (bonnet) 110 and the radiator device 34A are omitted from Figure 24. Figure 25 is a perspective view showing the arrangement relationship between the inverter device 72 and the transmission case 102B. Figures 26 and 27 are rear and top views, respectively, showing the arrangement relationship between the inverter device 72 and the transmission case 102B.

[0146] Figure 24 shows the motor 70, which is normally difficult to see due to various components housed in the front housing 110. Also shown in Figure 24 is the front portion of the handle stay cover 106X inside the cabin 105 and the lower end of the steering pipe 106Z that rotatably supports the steering shaft.

[0147] The motor 70 is supported by the front frame 102A. The rear end 102C of the front frame 102A is fixed to the front end 103C of the transmission case 102B, for example, by welding. The height of the rear end 102C of the front frame 102A is larger than that of other parts of the front frame 102A, improving the connection strength to the front end 103C of the transmission case 102B. In Figure 24, the aforementioned fixed housing portion 111 (not shown in Figure 24) is located above the motor 70 and in front of the handle stay cover 106X.

[0148] The motor 70 is supplied with U-phase, V-phase, and W-phase alternating current from the inverter device 72. In the illustrated example, the stator coil inside the motor 70 is connected to the wiring from the inverter device 72 via a three-phase terminal 103B provided on the motor fixing member 103A. The motor 70 is equipped with a sensor that detects the rotation of the rotor. The sensor is connected to a motor control circuit (not shown). The output (power) of the motor 70 can be determined to the required size depending on the size, weight, and application of the work vehicle.

[0149] The output shaft of the motor 70 is connected to the main shaft of a transmission, such as a truss transmission, housed in the transmission case 102B. The internal configuration of the transmission case 102B may be similar to that of a transmission in a known agricultural tractor, for example. An example of such a transmission is disclosed in International Publication No. 2022 / 038860, and its entire contents are incorporated herein by reference.

[0150] In this embodiment, the inverter device 72 is positioned to the side of the transmission case 102B and below the cabin 105. More specifically, a support member 75 that supports the inverter device 72 is fixed to the transmission case 102B. The support member 75 includes a first portion 75A connected to the lower part of the transmission case 102B and a second portion 75B extending parallel to the transmission case 102B in the plan view of Figure 27. The inverter device 72 is mounted on the second portion 75B. By utilizing such a support member 75, it becomes possible to effectively utilize the empty space formed below the cabin 105 to position the inverter device 72.

[0151] In this embodiment, the inverter device 72 is located close to the motor 70, which is positioned near the front end 103C of the transmission case 102B. This makes it possible to shorten the length of the wiring connecting the inverter device 72 and the motor 70. In addition, since the inverter device 72 contains multiple semiconductor switching elements such as power transistors, it tends to generate heat and become hot during operation. As in this embodiment, by not housing the inverter device 72 in the front housing 110 and positioning it below the cabin 105, it is possible to promote heat dissipation from the inverter device 72.

[0152] In this embodiment, the second portion 75B of the support member 75 may have a component 73 other than the inverter device 72 mounted on it (for example, an electronic component such as a capacitor). The support member 75 also has a third portion 75C that supports electrical components other than the inverter device 72. The third portion 75C is fixed to an extended portion 75B2 that extends vertically upward when the front end of the second portion 75B is bent vertically. In the plan view of Figure 27, the third portion 75C of the support member 75 is located in front of the second portion 75B. A storage battery 83 is placed on the third portion 75C.

[0153] As is clear from Figure 24, in a top view looking down, at least a portion of the upper surface of the battery 83 is exposed and does not overlap with the cabin 105. Also, as is clear from Figure 26, the third section 75C on which the battery 83 is mounted is located higher than the second section 75B. By adopting this configuration, access to the battery 83 by the operator becomes easier. According to this embodiment, the operator can easily perform tasks necessary for replacing the electrolyte and other maintenance of the battery 83, thereby increasing work efficiency.

[0154] The third section 75C may contain other components in place of, or along with, the battery 83. The height difference between the second section 75B and the third section 75C may be determined to facilitate the operator's work on the components mounted on the third section 75C.

[0155] 5.3. Electrical Circuit Modules Next, an example of the configuration of the electrical circuit module provided in the agricultural tractor in this embodiment will be described with reference to Figures 28 and 29. Figure 28 is a side view showing the electrical circuit module 77 in this embodiment, and Figure 29 is a schematic diagram showing the configuration of the electrical circuit module 77.

[0156] In this embodiment, the agricultural tractor 300 is equipped with an electrical circuit module 77 housed in a casing 77A, which is located on the side of the vehicle body 102. In other words, the electrical circuit module 77 is located on one side of the vehicle body 102, and the inverter device 72 is located on the other side of the vehicle body 102. More specifically, the electrical circuit module 77 in this embodiment includes a group of circuits electrically connected to the FC module 10 and the motor 70, and is fixed to the right side of the vehicle body 102, sandwiched between the front wheels 102F and the rear wheels 102R (see Figure 14). Specifically, the casing 77A of the electrical circuit module 77 is supported by a support member 79 fixed to the transmission case 102B. The support member 79 may be fixed to the lower end of the transmission case 102B, similar to the support member 75 for the inverter device 72 described above. The support member 75 and the support member 79 may also be integrally formed from the same metal member.

[0157] The electrical circuit module 77 may include, for example, a number of battery packs 80, a battery management unit 88, an ECU, or various electrical circuits 89, all of which are located within the housing 77A. The electrical circuits 89 may also include circuits that function as part of the inverter device 72.

[0158] In the side view of Figure 28, the housing 77A of the electrical circuit module 77 has a shape that does not overlap with the cabin 105. In this embodiment, the housing 77A has an "L" shape formed by connecting two rectangular parallelepipeds of roughly different sizes. The housing 77A has a portion (a relatively small, roughly rectangular parallelepiped-shaped portion) that is higher than the lower end 78A at the entrance of the cabin 105 between the cabin 105 and the front wheel 104F.

[0159] The upper end 78B of the battery pack 80 inside the housing 77A is lower than the lower end 78A at the entrance to the cabin 105. Because the battery pack 80 as a whole is relatively heavy compared to other electrical circuit components, this contributes to lowering the vehicle's center of gravity. On the other hand, the upper end 78C of a portion of the electrical circuit 89 is higher than the lower end 78A at the entrance to the cabin 105. This contributes to the efficient use of available space in the agricultural tractor. Furthermore, the lower end 78D of the housing 77A of the electrical circuit module 77 is lower than the front axle 104FX of the front wheel 104F. This allows for an increase in the volume of the housing 77A. Additionally, the support member 79 is preferably formed from a robust material so that it can effectively protect the housing 77A.

[0160] As described above, the electrical circuit module 77 in this embodiment is positioned to make effective use of the available space in the agricultural tractor 300. In conventional agricultural tractors powered by internal combustion engines, the space where a liquid fuel tank and other components would be located is no longer necessary in agricultural tractors equipped with an FC power generation system. Therefore, by positioning the electrical circuit module 77 in the space previously occupied by the fuel tank, it is possible to efficiently accommodate the necessary electrical circuits without increasing the vehicle length or width.

[0161] Furthermore, in order to cool the electrical components within the electrical circuit module 77, in this embodiment, the coolant flow path described with reference to Figure 4 is also provided inside the housing 77A of the electrical circuit module 77.

[0162] According to this embodiment, since a group of circuits (multiple electronic components) can be integrated within a specific area, the length of the wiring required to connect these electronic components can be shortened. Shortening the wiring reduces electrical resistance and suppresses noise interference. Furthermore, by placing heavy electrical components such as battery packs below the cabin 105, the vehicle's center of gravity can be lowered, contributing to improved driving stability.

[0163] As described above, this disclosure includes the work vehicles described in the following items.

[0164] [Item 1] A work vehicle equipped with a fuel cell and a fuel tank module, The aforementioned fuel tank module is Multiple fuel tanks for storing fuel to be supplied to the fuel cell, A valve system connected to the aforementioned multiple fuel tanks, A tank case housing the plurality of fuel tanks and the valve system, It has, The aforementioned multiple fuel tanks are A first fuel tank having a first length in a first direction, A second fuel tank having a second length shorter than the first length in the first direction, Includes, The first fuel tank and the second fuel tank are arranged in a second direction perpendicular to the first direction, A work vehicle wherein at least a portion of the valve system is located within the tank case in the space formed between the second fuel tank and the tank case.

[0165] [Item 2] The plurality of fuel tanks include a third fuel tank having a third length shorter than the first length in the first direction. The work vehicle according to item 1, wherein at least the other part of the valve system is located within the tank case in the space formed between the third fuel tank and the tank case.

[0166] [Item 3] The work vehicle described in item 2, wherein the third length is equal to the second length.

[0167] [Item 4] The valve system includes an on-off valve and a pressure reducing valve located within the tank case, as described in any one of items 1 to 3 of the work vehicle.

[0168] [Item 5] A work vehicle according to any one of items 1 to 4, comprising a fuel gas sensor located inside the aforementioned tank case.

[0169] [Item 6] The tank case has a bottom plate that extends along a plane defined by the first direction and the second direction, The work vehicle according to any one of items 1 to 5, wherein the plurality of fuel tanks are placed on the bottom plate.

[0170] [Item 7] The work vehicle according to any one of items 1 to 6, wherein each of the plurality of fuel tanks is a high-pressure hydrogen tank having a cylindrical portion extending in the first direction.

[0171] [Item 8] A motor connected to the fuel cell, A vehicle body supporting the fuel cell, the fuel tank module, and the motor, the vehicle body rotatably supports the front wheels and rear wheels, A work vehicle as described in any one of items 1 to 7, comprising:

[0172] [Item 9] The driver's seat and, A fixing frame that straddles the driver's seat and is fixed to the vehicle body and supports the fuel tank, A work vehicle as described in any one of items 1 to 8, which is equipped with the following features.

[0173] [Item 10] The aforementioned work vehicle is an agricultural machine, a work vehicle as described in any one of items 1 through 9.

[0174] [Item 11] A work vehicle according to any one of items 1 to 10, comprising a power take-off shaft driven by the aforementioned motor. [Industrial applicability]

[0175] The technology disclosed herein is suitable for work vehicles such as agricultural tractors, riding cultivators, and vegetable transplanters. It can be used. [Explanation of Symbols]

[0176] 10...Fuel cell module, 11...FC stack, 40...Boost circuit, 34...Radiator unit, 40...Boost circuit, 50...Fuel tank, 51...Tank case, 70...Motor, 71...Output shaft, 72...Inverter unit, 74...Power transmission system, 76...Power take-off (PTO) shaft, 80...Battery pack, 81...Number 1 DC-DC converter, 82...2 DC-DC converter, 83...Battery, 85...Air conditioning compressor, 86...Heater, 100...Work vehicle, 102...Body, 102A...Front frame, 102B...Transmission case, 104...Wheels, 104F...Front wheels, 104R...Rear wheels, 107...Driver's cab, 120...Fixed frame

Claims

1. A work vehicle equipped with a fuel cell and a fuel tank module, The aforementioned fuel tank module is Multiple fuel tanks for storing fuel to be supplied to the fuel cell, A valve system connected to the aforementioned multiple fuel tanks, A tank case housing the plurality of fuel tanks and the valve system, It has, The aforementioned multiple fuel tanks are A first fuel tank having a first length in a first direction, A second fuel tank having a second length shorter than the first length in the first direction, Includes, The first fuel tank and the second fuel tank are arranged in a second direction perpendicular to the first direction, The first fuel tank and the second fuel tank each have a first solenoid valve and a second solenoid valve for opening and closing the fuel tank, The first solenoid valve and the second solenoid valve are positioned side by side in the second direction, A work vehicle wherein at least a portion of the valve system is located within the tank case in a space formed between the second fuel tank and the tank case, on the side of the second fuel tank opposite to the second solenoid valve.

2. The plurality of fuel tanks include a third fuel tank having a third length shorter than the first length in the first direction. The work vehicle according to claim 1, wherein at least another part of the valve system is located within the tank case in the space formed between the third fuel tank and the tank case.

3. The work vehicle according to claim 2, wherein the third length is equal to the second length.

4. The work vehicle according to any one of claims 1 to 3, wherein the valve system includes an on-off valve and a pressure reducing valve located inside the tank case.

5. The work vehicle according to claim 4, further comprising a fuel gas sensor located inside the tank case.

6. The tank case has a bottom plate that extends along a plane defined by the first direction and the second direction, The work vehicle according to any one of claims 1 to 3, wherein the plurality of fuel tanks are placed on the bottom plate.

7. The work vehicle according to claim 6, wherein each of the plurality of fuel tanks is a high-pressure hydrogen tank having a cylindrical portion extending in the first direction.

8. A motor connected to the fuel cell, A vehicle body supporting the fuel cell, the fuel tank module, and the motor, the vehicle body rotatably supports the front and rear wheels, A work vehicle according to claim 1, comprising:

9. The driver's seat and, A vehicle body supporting the driver's seat, the fuel cell, and the fuel tank module, A fixing frame that straddles the driver's seat and is fixed to the vehicle body and supports the fuel tank, A work vehicle according to claim 1, comprising:

10. The work vehicle according to claim 8, wherein the work vehicle is an agricultural machine.

11. The work vehicle according to claim 10, further comprising a power take-off shaft driven by the motor.

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