Work vehicle, and control device and control method for work vehicle

Abstract

This work vehicle is provided with: a fuel cell module having a fuel cell stack; at least one fuel tank accommodating fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a traveling device driven by the motor; the power output shaft is driven by the motor and is connected with a working tool; and a control device. The control device stops the supply of the fuel or the oxidizing gas to the fuel cell module in response to an operation stop command, and thereafter rotates the motor in a state in which power transmission from the motor to the travel device is stopped, and discharges residual charges in a circuit group connected to the motor.

Description

Technical Field

[0001] The present disclosure relates to a work vehicle, a control device for the work vehicle, and a control method for the work vehicle. Background Art

[0002] In the automotive field, which is mainly aimed at moving "people" or "objects", electric vehicles (EVs) that use electric motors (hereinafter referred to as "motors") instead of internal combustion engines to generate driving force (traction) for traveling are becoming popular.

[0003] On the other hand, in order to realize a decarbonized society, it is also required to reduce the carbon dioxide (CO2) emitted by work vehicles such as tractors used in the fields. 2 ) volume. Unlike general cars, work vehicles such as tractors need to tow work machines called work tools to perform agricultural work such as tilling. Therefore, in order to realize the electrification of work vehicles, there are issues that need to be solved that are different from the electrification of passenger cars.

[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.

[0005] Patent document 2 discloses a vehicle having a fuel cell system. When the ignition is turned off and the entire vehicle system is turned off, the vehicle performs a discharge process to consume the charge remaining in the high voltage system provided in the vehicle. The charge remaining in the high voltage system is the charge remaining in the circuit other than the battery, for example, the charge remaining in the capacitor included in the circuit. In the discharge process, the charge is consumed by a heater that heats water in a water tank storing water generated by power generation of the fuel cell.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2002-225577

[0009] Patent Document 2: Japanese Patent Application Publication No. 2022-46376 Summary of the invention

[0010] Problem that the invention aims to solve

[0011] The present disclosure provides a technology for efficiently discharging residual electric charge when the operation is stopped in a work vehicle equipped with a fuel cell module.

[0012] Means used to solve problems

[0013] In an exemplary non-limiting embodiment, a working vehicle of one embodiment of the present disclosure includes: a fuel cell module having a fuel cell stack; at least one fuel tank containing fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a travel device driven by the motor; a power output shaft driven by the motor and connected to a work tool; and a control device. The control device stops the supply of the fuel or oxidizing gas to the fuel cell stack in response to an instruction to stop the operation, and then rotates the motor in a state where the power transmission from the motor to the travel device is stopped, so as to discharge the residual charge in the circuit group connected to the motor.

[0014] The inclusive or specific manner of the present disclosure can be implemented using a device, a system, a method, an integrated circuit, a computer program, or a computer-readable non-temporary storage medium, or any combination thereof. The computer-readable storage medium may include both volatile storage media and non-volatile storage media. The device may also be composed of multiple devices. In the case where the device is composed of more than two devices, the two or more devices may be configured in one device or separately configured in two or more separate devices.

[0015] Effects of the Invention

[0016] According to the embodiment of the present disclosure, residual electric charge can be efficiently discharged when the operation is stopped. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a plan view schematically showing a basic configuration example of a work vehicle according to the present disclosure.

[0018] Figure 2 This is a diagram showing a basic configuration example of a fuel cell power generation system mounted on a work vehicle.

[0019] Figure 3 This is a block diagram schematically showing an example of electrical connection and power transmission between components of the work vehicle of the present disclosure.

[0020] Figure 4 It is a block diagram schematically showing the path of an electric signal (thin solid line) and the path of a coolant (dashed line) between components in the work vehicle of the present disclosure.

[0021] Figure 5 It is a perspective view schematically showing a configuration example of a work vehicle in an embodiment of the present disclosure.

[0022] Figure 6 It is a side view schematically showing a configuration example of a work vehicle in an embodiment of the present disclosure.

[0023] Figure 7 This is a flowchart showing an example of the discharge process of the work vehicle.

[0024] Figure 8 This is a flowchart showing another example of the discharge process of the work vehicle.

[0025] Fig. 9 This is a flowchart showing another example of the discharge process of the work vehicle. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present disclosure. However, sometimes more detailed descriptions than necessary are omitted. For example, detailed descriptions of matters that are already known and repeated descriptions related to substantially the same structure are sometimes omitted. This is to avoid the following description from becoming unnecessarily lengthy and to make it easy for those skilled in the art to understand. In addition, the inventor provides the drawings and the following description in order to enable those skilled in the art to fully understand the present disclosure, and does not intend to limit the subject matter described in the claims through them. In the following description, the same figure marks are marked on structural elements with the same or similar functions.

[0027] The following embodiments are for illustration only, and the technology disclosed in the present invention is not limited to the following embodiments. For example, the numerical values, shapes, materials, steps, the order of the steps, the layout of the display screen, etc. shown in the following embodiments are only examples, and various changes can be made as long as there is no technical contradiction. In addition, as long as there is no technical contradiction, one method can be combined with other methods.

[0028] The "work vehicle" in the present disclosure refers to a vehicle (vehicle) used to perform work at a work site. "Work site" refers to any place where work is performed, such as a farmland, forest, or construction site. "Field" refers to any place where agricultural work is performed, such as an orchard, dry field, paddy field, grain farm, or ranch. The work vehicle can be an agricultural machine such as a tractor, a rice transplanter, a combine harvester, a passenger management machine, or a passenger lawn mower, or a vehicle used for non-agricultural purposes such as a construction work vehicle or a snowplow. The work vehicle in the present disclosure can be equipped with a work tool (also called a "work machine" or "work device") corresponding to the work content at least one of its front and rear parts. Sometimes, driving a work vehicle while performing work is referred to as "work driving."

[0029] In addition, "agricultural machinery" refers to machinery used for agricultural purposes. Examples of agricultural machinery include tractors, harvesters, rice transplanters, passenger management machines, vegetable transplanters, mowers, seed drills, fertilizer spreaders, and agricultural mobile robots. There are cases where not only work vehicles such as tractors function as "agricultural machinery" alone, but also work tools installed on or towed by work vehicles and the work vehicles as a whole function as a "agricultural machinery". Agricultural machinery performs agricultural operations such as tilling the ground in the field, sowing, pest control, fertilizing, planting or harvesting crops.

[0030] 1. <Basic structure of work vehicle>

[0031] The basic structure and operation example of the work vehicle of the present disclosure will be described. The work vehicle described below is equipped with a motor and a fuel cell power generation system (hereinafter referred to as "FC power generation system") that generates power required to drive the motor.

[0032] Figure 1 1 is a top view schematically showing an example of the basic structure of the work vehicle 100 of the present disclosure. In the present disclosure, the direction of travel when the work vehicle 100 is traveling straight forward is referred to as the "front direction", and the direction of travel when 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 "front direction" is referred to as the "right direction", and the direction extending perpendicularly to the left relative to the "front direction" is referred to as the "left direction". Figure 1 In the figure, the “front direction”, “rear direction”, “right direction” and “left direction” are represented by arrows pointing “front”, “rear”, “right” and “left” respectively. Sometimes both the front direction and the rear direction are collectively referred to as the “front-rear direction”.

[0033] The working vehicle 100 in the illustrated example is, for example, a tractor as an example of agricultural machinery. The technology disclosed in the present invention is not limited to working vehicles such as tractors, but can also be applied to other types of working vehicles. In addition, the working vehicle 100 can travel in the field while installing or towing a working tool and performing agricultural operations corresponding to the type of the working tool. In addition, the working vehicle 100 can also travel in the field and outside the field (including roads) in a state where the working tool is raised or in a state where the working tool is not installed.

[0034] Similar to conventional tractors, the work vehicle 100 has a vehicle body (vehicle frame) 102 that supports left and right front wheels 104F and left and right rear wheels 104R so as to be rotatable. The vehicle body 102 includes a front frame 102A provided with the front wheels 104F and a transmission box 102B provided with the rear wheels 104R. The front frame 102A is fixed to the front portion of the transmission box 102B. The front wheels 104F and the rear wheels 104R are sometimes collectively referred to as wheels 104. Strictly speaking, the wheels 104 are hubs with tires installed. In the present disclosure, "wheels" in principle refer to the whole of "hubs and tires". One or both of the front wheels 104F and the rear wheels 104R can be replaced by a plurality of wheels (tracks) with an infinite track installed, i.e., a wheel with a tire. In this specification, the left and right front wheels 104F and the left and right rear wheels 104R, the axles that rotate these four wheels, and the braking devices (brakes) that brake the axles may be collectively referred to as a "travel device".

[0035] Figure 1 The work vehicle 100 in the example includes a fuel cell module (FC module) 10 and a motor 70 supported directly or indirectly by a front frame 102A. The FC module 10 includes a fuel cell stack (FC stack), which functions as an on-board generator that generates electricity from fuel as described later. Hereinafter, "FC module" or "FC stack" may be referred to simply as "fuel cell".

[0036] The motor 70 is electrically connected to the FC module 10. The motor 70 is capable of converting the electricity generated by the FC module 10 into mechanical motion (power), thereby generating the driving force (traction) required for the travel of the work vehicle 100. An example of the motor 70 is an AC synchronous motor. Since the FC stack of the FC module 10 generates a DC current, in the case where the motor 70 is an AC synchronous motor, a circuit group including an inverter device is provided between the FC stack and the motor 70 to convert the DC current into an AC current. A portion of this circuit group may be located inside the FC module 10. In addition, another portion of the circuit group may also be installed on the motor 70 as a drive circuit of the motor 70.

[0037] The motor 70 has a rotating output shaft 71. The torque of the output shaft 71 is transmitted to the rear wheel 104R via mechanical components such as a transmission (speed change device) and a rear wheel differential device (differential gear device) arranged inside the transmission box 102B. In other words, the power generated by the motor 70 as a power source is transmitted to the rear wheel 104R through a power transmission system (power transmission system) 74 including a transmission arranged in the transmission box 102B. Therefore, the "transmission box" can also be referred to as a "transmission box". In addition, in the four-wheel drive mode, part of the power of the motor 70 is also transmitted to the front wheel 104F. The power of the motor 70 can be used not only for the travel of the working vehicle 100, but also for driving the working tool. Specifically, a power output (PTO) shaft 76 is provided at the rear end of the transmission box 102B. The PTO shaft 76 is driven by the motor 70 and is connected to the working tool. The torque of the output shaft 71 of the motor 70 is transmitted to the PTO shaft 76. A work tool mounted on or towed by work vehicle 100 can receive power from PTO shaft 76 and perform operations corresponding to various works. Motor 70 and power transmission system 74 may also be collectively referred to as an electric powertrain.

[0038] Thus, in the work vehicle 100 of the present disclosure, an internal combustion engine such as a diesel engine is not mounted, but an FC module 10 and a motor 70 are mounted. In addition, the output shaft 71 of the motor 70 is mechanically coupled to a power transmission system 74 such as a transmission in the transmission case 102B. Compared with an internal combustion engine, the motor 70 can effectively generate torque within a relatively wide speed range. However, by utilizing the power transmission system 74 including the transmission, performing multi-stage or stepless speed change actions, it is easy to adjust the torque and speed from the motor 70 within a wider range. Therefore, not only can the driving of the work vehicle 100 be effectively performed, but also a variety of operations using work tools can be effectively performed.

[0039] In addition, some functions of the power transmission system 74 may be deleted according to the purpose or size of the work vehicle 100. For example, part or all of the transmission that performs the speed change function may be omitted. The number and mounting position of the motor 70 are also not limited to Figure 1 Example shown.

[0040] The work vehicle 100 has at least one fuel tank 50 for storing fuel to be supplied to the FC module 10. Figure 1 In the figure, for the sake of simplicity, one fuel tank 50 is described. In some embodiments, a plurality of fuel tanks 50 are contained in a tank case to form a fuel tank module. As described later, the fuel tank 50 is supported by a member fixed to the vehicle body 102. The FC module 10 and the fuel tank 50 are connected by piping and an on-off valve to form a vehicle-mounted FC power generation system. The structure and operation of the FC power generation system will be described later.

[0041] In the work vehicle 100 in the embodiments described later, a driver's seat is supported by a vehicle body 102. The driver's seat can be surrounded by a driver's cab supported by the vehicle body 102. In the embodiments described later, 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 accommodated in at least one "accommodating body". The "accommodating body" functions as a housing, for example, and has a function of protecting the FC module 10 and the fuel tank 50 from sunlight and wind and rain. In addition, such an accommodating body can also control the diffusion of fuel gas into the atmosphere in the case where fuel gas leaks from the FC module 10 or the fuel tank 50, thereby facilitating the detection of fuel gas.

[0042] The FC module 10 can be accommodated in a front housing called an "engine hood", for example. The front housing is a part of the "accommodating body". The front housing is supported by the front part (front frame 102A) of the vehicle body 102. As described above, the fuel tank 50 can be accommodated in a tank body. The tank body is supported directly or indirectly by the vehicle body 102.

[0043] 2. <FC Power Generation System>

[0044] Next, with reference to Figure 2 , a basic structural example of the FC power generation system 180 mounted on the work vehicle 100 will be described.

[0045] Figure 2 The FC power generation system 180 shown functions as an in-vehicle power generation system in the Figure 1 work vehicle 100. 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 work tools towed or mounted on the work vehicle 100.

[0046] In the illustrated example, the FC power generation system 180 includes an FC module 10 and at least one fuel tank 50 that stores fuel supplied to the FC module 10. In addition, the FC power generation system 180 has a radiator device 34 for cooling the FC module 10.

[0047] The FC module 10 has 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 as main components. These components are accommodated in the housing of the FC module 10 and are connected to each other through electrical connection or fluid connection.

[0048] The FC stack 11 generates electricity through an electrochemical reaction between "anode gas" as a fuel and "cathode gas" as an oxidizing gas. The FC stack 11 in this example is a solid polymer fuel cell. The FC stack 11 has a stacking structure in which a plurality of single cells (fuel cell single cells) are stacked. The single cell has an electrolyte membrane formed by, for example, an ion exchange membrane, an anode formed on one side of the electrolyte membrane, a cathode formed on the other side of the electrolyte membrane, and a pair of separators sandwiching the anode and the cathode from both sides. The voltage generated in the 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.

[0049] Anode gas is supplied to the anode of the FC stack 11. The anode gas is called "fuel gas" or simply "fuel". In the embodiment of the present disclosure, the anode gas (fuel) is hydrogen. Cathode gas is supplied to the cathode. The cathode gas is an oxidizing gas such as air. The anode is called the fuel electrode and the cathode is called the air electrode.

[0050] In the anode, an electrochemical reaction represented by the following formula (1) occurs.

[0051] 2H 2 →4H + +4e - …Formula (1)

[0052] In the cathode, an electrochemical reaction represented by the following formula (2) occurs.

[0053] 4H + +4e - +O 2 →2H 2 O…Formula (2)

[0054] As a whole, the reaction of the following formula (3) occurs.

[0055] 2H 2 +O 2 →2H 2 O…Formula (3)

[0056] The anode gas after the above reaction is called "anode exhaust gas", and the cathode gas after the above reaction is called "cathode exhaust gas".

[0057] The air compressor 12 supplies air sucked from the outside as cathode gas to the cathode of the FC stack 11. The cathode gas supply system including the air compressor 12 has a cathode gas supply pipe 13, a cathode exhaust pipe 14 and a bypass pipe 15. The cathode gas supply pipe 13 allows the cathode gas (air) supplied from the air compressor 12 to flow to the cathode of the FC stack 11. The cathode exhaust pipe 14 allows the cathode exhaust gas discharged from the FC stack 11 to flow to the outside air. The bypass pipe 15 branches from the cathode gas supply pipe 13 downstream of the air compressor 12, bypasses the FC stack 11 and is connected to the cathode exhaust pipe 14. A control valve 16 for adjusting the flow rate of the cathode gas flowing to the bypass pipe 15 is provided in the bypass pipe 15. A shut-off valve 17 for selectively shutting off the flow of the cathode gas to the FC stack 11 is provided in the cathode gas supply pipe 13. A pressure regulating valve 18 for adjusting the back pressure of the cathode gas is provided in the cathode exhaust pipe 14.

[0058] The cathode gas supply system of the FC module 10 includes a rotation speed sensor S1 for detecting the rotation speed of the air compressor 12 and a gas flow rate sensor S2 for detecting the flow rate of the cathode gas flowing in the cathode gas supply pipe 13. The control valve 16, the shutoff valve 17 and the pressure regulating valve 18 are, for example, solenoid valves.

[0059] The fuel circulation pump 24 supplies the fuel gas (anode gas) delivered from the fuel tank 50 to the anode 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 exhaust pipe 22 and a circulation flow path 23. The anode gas supply pipe 21 allows the anode gas supplied from the fuel tank 50 to flow to the anode of the FC stack 11. The fuel tank 50 in the embodiment of the present disclosure is a hydrogen tank that stores high-pressure hydrogen gas.

[0060] The anode exhaust gas pipe 22 is for the anode exhaust gas discharged from the FC stack 11 to flow. The anode exhaust gas is guided to the gas-liquid separation device 25 through the anode exhaust gas pipe 22 to remove moisture. The anode exhaust gas from which moisture has been removed is returned to the anode gas supply pipe 21 via the circulation flow path 23 using the fuel circulation pump 24. The anode exhaust gas circulating in the circulation flow path 23 can be discharged via the anode exhaust gas pipe 22 by opening the exhaust valve 26. The moisture stored in the gas-liquid separation device 25 can be discharged via the anode exhaust gas pipe 22 by opening the exhaust valve 26. The exhaust valve 26 is, for example, a solenoid valve. In the example of the figure, the anode exhaust gas pipe 22 is connected to the cathode exhaust gas pipe 14. By adopting such a structure, the anode exhaust gas containing unreacted anode gas that does not contribute to the electrochemical reaction is circulated and supplied to the FC stack 11 again, thereby improving the utilization efficiency of the anode gas.

[0061] In order to improve the performance of the FC stack 11, its temperature control is important. When electricity is generated by the reaction of hydrogen and oxygen to produce water, heat is also generated, so cooling is required. Figure 2, a coolant circulation system including a coolant pump 31 for the FC stack 11 is described, but as described later, a cooling circulation system for other electrical components may also be provided. In addition, the air compressor 12, the fuel circulation pump 24, and the coolant pump 31 of the FC module 10 are respectively operated by built-in motors. These motors are also electrical components.

[0062] Figure 2 The coolant circulation system including the coolant pump 31 has a coolant supply pipe 32, a coolant discharge pipe 33, a radiator device 34 and a temperature sensor S3. The coolant circulation system can adjust the temperature of the FC stack 11 to 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 in the coolant flow path formed between the single 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 inflowing coolant and the outside air, and supplies the coolant whose temperature has been lowered to the coolant supply pipe 32 again.

[0063] The coolant pump 31 is provided in the coolant supply pipe 32 or the coolant discharge pipe 33 in such a manner as to deliver the coolant to the FC stack 11. A bypass flow path of the coolant may be provided between the coolant discharge pipe 33 and the coolant supply pipe 32. In this case, a diverter valve is provided at a branch point where the coolant bypass flow path branches from the coolant discharge pipe 33. The diverter valve can adjust the flow rate of the coolant flowing to the bypass flow path. The temperature sensor S3 detects the temperature of the coolant flowing in the coolant discharge pipe 33.

[0064] The coolant used to cool the FC stack 11 is circulated in the flow path by an electric pump (coolant pump) 31 for the coolant. A coolant control valve may be provided downstream of the FC stack 11. The coolant control valve adjusts the ratio of the coolant flowing to the radiator device 34 and the coolant bypassing the radiator device 34, so that the temperature of the coolant can be controlled with higher accuracy. Moreover, by controlling the water delivery amount of the coolant pump, the coolant temperature difference between the inlet and outlet of the FC stack 11 can also be controlled within a desired range. The temperature of the coolant in the FC stack 11 can be controlled to a temperature at which the power generation efficiency of the FC stack 11 is high, for example, about 70°C.

[0065] Preferably, the coolant flowing in the FC stack 11 has higher insulation than the coolant used to cool ordinary electrical components. A high voltage of, for example, more than 300 volts is generated in the FC stack 11, so by increasing the resistance of the coolant, it is possible to suppress current leakage through the coolant or the radiator device 34, etc. As the use of the coolant progresses, the resistance of the coolant sometimes decreases. This is because ions dissolve in the coolant flowing in the FC stack 11. In order to remove such ions from the coolant to improve insulation, it is preferred that an ion exchanger is arranged in the flow path of the coolant.

[0066] The boost circuit 40 can increase the voltage output from the FC stack 11 through power generation to a desired level. The back stage of the boost circuit 40 is connected to a circuit of a strong electric system including an inverter device for motor drive. In addition, the back stage of the boost circuit 40 can also be connected in parallel with a circuit of a weak electric system via a step-down circuit.

[0067] The control device 42 is an electronic control unit (ECU) that controls the power generation of 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. The control device 42 controls the operation of the air compressor 12, the fuel circulation pump 24, the coolant pump 31, and various valves based on the operating state of the FC power generation system 180 and instructions output from a higher-level computer or other ECUs, thereby controlling the power generation of the FC stack 11. The control device 42 includes, for example, a processor, a storage device, and an input / output interface.

[0068] In the following description, for simplicity, “anode gas” is referred to as “fuel gas” or “fuel”, and “anode gas supply pipe” is referred to as “pipe”.

[0069] 3.<System configuration example of work vehicle>

[0070] Next, refer to Figure 3 and Figure 4 , an example of the system configuration of the work vehicle 100 is described. Figure 3 This is a block diagram schematically showing an example of electrical connection and power transmission between components of the work vehicle 100 of the present disclosure. Figure 4 It means ratio Figure 3 A more detailed block diagram of the structure is shown in the following example. Figure 4 Schematically shows the path of the electric signal (thin solid line) and the path of the coolant (dashed line) between the components in the work vehicle 100.

[0071] First, refer to Figure 3, an example of electrical connection and power transmission of components is described. Electrical connection includes both strong current system and weak current system. For example, the electrical connection of the strong current system provides the power supply voltage of the inverter device. For example, the electrical connection of the weak current system provides the power supply voltage of the electronic components operating at a relatively low voltage.

[0072] exist Figure 3 In the example shown, the work vehicle 100 has 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 by the FC stack 11 of the FC module 10 is supplied to the inverter device 72 after being boosted by the boost circuit 40. The inverter device 72 converts the DC voltage into, 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 includes a rotating rotor and a stator having a plurality of coils electrically connected to the inverter device 72. The rotor is connected to the output shaft 71, for example, via a reduction gear (reducer) or directly. The motor 70 rotates the output shaft 71 at a torque and a speed controlled according to the waveform of the three-phase AC voltage from the inverter device 72.

[0073] Figure 4 The inverter device 72 shown has an ECU 73 that controls the motor 70. The ECU 73 controls the switching action (on or off) of each of the plurality of power transistors included in the bridge circuit of the inverter device 72. The ECU 73 can be connected to the plurality of power transistors in the bridge circuit via a pre-driver (sometimes referred to as a "gate driver"). The ECU 73 can be configured to operate under the control of a host computer such as the control device 60.

[0074] The torque of the output shaft 71 of the motor 70 is transmitted to the power transmission system 74. The power transmission system 74 operates with the motor 70 as a power source and can drive Figure 1wheels 104R, 104F and / or PTO shaft 76. Such a power transmission system 74 may have the same structure or a similar structure as a power transmission system in a conventional tractor including an internal combustion engine such as a diesel engine. For example, by adopting a power transmission system used in an agricultural tractor, etc., it is possible to suppress the design cost and manufacturing cost of a working vehicle 100 for agricultural use equipped with an FC power generation system. The power transmission system 74 includes: a travel system power transmission mechanism that transmits power from the motor 70 to the left and right rear wheels 104R via a clutch, a transmission, and a rear wheel differential device, etc.; and a PTO system power transmission mechanism that transmits power from the motor 70 to the PTO shaft 76. The power transmission system 74 includes a PTO clutch that switches between a state (connected state) in which the power from the motor 70 is transmitted to the PTO shaft 76 and a state (disconnected state) in which the power is not transmitted. The PTO clutch can be switched manually by the driver operating the operating device, or can be switched by automatic control. Figure 1 The transmission case 102B can also be divided into a front case (transmission case) containing a clutch such as a PTO clutch and a transmission, and a rear case (differential gear case) containing a rear wheel differential device, etc. The rear case is also called a rear axle case.

[0075] The work vehicle 100 has a secondary battery (battery pack) 80 that temporarily stores the electric energy generated by the power generation of the FC module 10. Examples of the battery pack 80 include a lithium-ion battery pack. The battery pack 80 is electrically connected to the FC module 10 and is electrically connected to the motor 70 via the inverter device 72. The battery pack 80 can supply power to the inverter device 72 when necessary in cooperation with the FC module 10 or independently. As the battery pack 80, various battery packs used in passenger electric vehicles can be used. Hereinafter, the battery pack 80 is sometimes referred to as "battery 80".

[0076] In addition to the motor 70 and the inverter device 72, the work vehicle 100 also has various electrical components (on-board electronic components) that are operated by electricity. Examples of electrical components include solenoid valves such as the on-off valve 20, the air-cooling fan of the radiator device 34, the electric pump of the refrigeration 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. In addition, the first DC-DC converter 81, the second DC-DC converter 82, and the battery 83 for obtaining a power supply voltage suitable for the operation of these electrical components may also be included in the electrical components. Moreover, various electronic components not shown in the figure (lights, electric motors of hydraulic systems, etc.) may also be included in the electrical components. These electrical components may be, for example, the same electronic components as those of conventional agricultural tractors.

[0077] exist Figure 3In the example of FIG. 1 , the first DC-DC converter 81 is a circuit that reduces the voltage output from the boost circuit 40 of the FC module 10 to a first voltage, for example, 12 volts. The storage battery 83 is, for example, a lead storage battery, and can store electric energy using the voltage output from the first DC-DC converter 81. The storage battery 83 can be used as a power source for various electrical components such as a lamp, for example.

[0078] Figure 3 The work vehicle 100 shown has not only a first DC-DC converter 81 but also a second DC-DC converter 82 as a voltage conversion circuit for reducing the high voltage output by the FC module 10. The second DC-DC converter 82 is a circuit for reducing the voltage (e.g., several hundred volts) output from the boost circuit 40 of the FC module 10 to a second voltage higher than the first voltage, e.g., 24 volts. For example, the air cooling fan of the radiator device 34 can be operated using the voltage output from the second DC-DC converter 82. In addition, the radiator device 34 is Figure 3 Although described as a single component, one work vehicle 100 may include a plurality of radiator devices 34 . In addition, the electric pump of the cooling compressor 85 and the electric heater 86 can also be operated by the voltage output from the second DC-DC converter 82 .

[0079] Figure 3 The work vehicle 100 shown has a temperature control device for cooling or heating the FC stack 11 included in the FC power generation system. The operation of such a temperature control device requires relatively large power. The relatively high voltage of 24 volts output by the second DC-DC converter 82 is supplied to such a temperature control device. The temperature control device in this embodiment includes a radiator device 34 for dissipating heat from the refrigerant cooling the FC stack 11, and the relatively high voltage of 24 volts (second voltage) 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 can also be supplied to the heater. The relatively high voltage output by the second DC-DC converter 82 can also be supplied to an air conditioning device such as a refrigeration compressor 85.

[0080] In addition, the work vehicle 100 may also include 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. When the work vehicle 100 includes another motor different from the motor 70, for example, the third voltage may be used as a power source for such another motor.

[0081] In an agricultural work vehicle equipped with a fuel cell power generation system, in addition to electrical components required for agricultural work, electrical components required for fuel cell power generation are also included, so the magnitude of voltage suitable for each electrical component may be different. According to the embodiment of the present disclosure, an appropriate magnitude of voltage can be supplied.

[0082] exist Figure 3 In the example of FIG. 5 , a plurality of fuel tanks 50 are housed in a tank case 51. The fuel tanks 50 are connected to a filling port (fuel filling port) 52 for filling fuel from the outside. This connection is performed by a pipe 21 for flowing the fuel gas. In addition, the fuel tanks 50 are connected to the FC module 10 via the pipe 21 provided with an on-off valve 20. When hydrogen is used as the fuel gas, these pipes 21 can be formed of a material with high resistance to hydrogen embrittlement, for example, austenitic stainless steel such as SUS316L.

[0083] The tank case 51 is provided with a valve space 53, and various valves including a pressure reducing valve are arranged in the valve space 53. The pipe 21 connects the fuel tank 50 and the FC module 10 via various valves provided in the valve space 53. The fuel gas whose pressure is reduced by the pressure reducing valve flows in the pipe 21 connecting the tank case 51 and the FC module 10. When the fuel gas is hydrogen, the fuel tank 50 can be filled with high-pressure hydrogen of, for example, 35 MPa or more, but the hydrogen after passing through the pressure reducing valve can be reduced to, for example, about 2 atmospheres or less.

[0084] Next reference Figure 4 .exist Figure 4 In addition to Figure 3 In addition to the description of , a plurality of ECUs and a user interface 1 that communicate within the work vehicle 100 are also described. The communication can be performed via a CAN bus wiring or the like that serves as a path (thin solid line) for electrical signals. Figure 4 The cooling system for achieving thermal management of the components is also described. Specifically, the path of the cooling liquid is schematically shown (dashed line).

[0085] In addition, as described above, the first DC-DC converter 81 and the second DC-DC converter 82 can output voltages of different magnitudes. The first DC-DC converter 81 and the second DC-DC converter 82 are also provided with an ECU that controls the respective voltage conversion circuits. Similar to other ECUs, the relatively low first voltage output by the first DC-DC converter 81 is provided to these ECUs.

[0086] exist Figure 4In the example, the work vehicle 100 has a cooling system that circulates coolant using coolant pumps 31A and 31B. These coolant pumps 31A and 31B are arranged inside the FC module 10. The cooling system in this example includes a first radiator device 34A that is responsible for cooling the FC stack 11 and a second radiator device 34B that is responsible for cooling other electrical components. The cooling system has a flow path (first flow path) for the coolant to flow between the FC stack 11 and the first radiator device 34A. In addition, the cooling system has a flow path (second flow path) for the coolant to flow between the electrical components including the motor 70 and the second radiator device 34B. In addition, in Figure 4 In the example, for example, a heater core 87 for heating the cabin is provided, and the coolant flowing in the first radiator device 34A flows in the heater core 87 .

[0087] The user interface 1 includes an operating device 2 such as an accelerator pedal (or accelerator lever), a main meter 4 , and an FC meter 6 . Figure 4 The work vehicle 100 shown further includes a control device 60 and a storage device 7 . The control device 60 includes a main ECU 3 and an FC system ECU 5 .

[0088] The main ECU 3 is connected to the FC system ECU 5, the operating device 2, the main meter 4, and the storage device 7. The main ECU 3 controls the overall operation of the work vehicle 100. The main meter 4 can display various parameters that determine the driving state or the operation state of the work vehicle 100. The FC system ECU 5 controls the operation of the FC power generation system. The FC system ECU 5 is connected to the FC meter 6. The FC meter 6 can display various parameters that determine the operation state of the FC power generation system.

[0089] The storage device 7 includes one or more storage media such as a flash memory or a magnetic disk. The storage device 7 stores various data generated by the main ECU 3 and the FC system ECU 5. The storage device 7 also stores a computer program that causes the main ECU 3 and the FC system ECU 5 to perform desired actions. Such a computer program can be provided to the work vehicle 100 via a storage medium (e.g., a semiconductor memory or an optical disk) or an electrical communication line (e.g., the Internet). Such a computer program can be sold as commercial software.

[0090] The cells of the battery pack 80 are controlled by a battery management unit (BMU). The BMU has a voltage monitor for each cell of the battery, a circuit for monitoring overcharge / overdischarge, cell balance control, and a CPU (Central Processing Unit). These circuits and the CPU can be mounted on a battery controller substrate.

[0091] 4. <Implementation Method>

[0092] (4.1. Basic structure of work vehicle)

[0093] Next, refer to Figure 5 and Figure 6 , the basic structure of an embodiment of the work vehicle disclosed in the present invention is described. Figure 5 It is a perspective view schematically showing a configuration example of a work vehicle 200 in the present embodiment. Figure 6 It is a side view schematically showing a configuration example of a work vehicle 200 in the present embodiment.

[0094] like Figure 6 As shown, the work vehicle 200 in this embodiment includes the FC module 10, the fuel tank 50, the motor 70, the driver's seat 107, the operation terminal 400, the control device 60, the travel device including the wheels 104, and the vehicle body 102. The work vehicle 200 has the same Figure 1 The structure is the same as that of the work vehicle 100 described above. Figure 4 As shown, the control device 60 includes a main ECU 3 and a FC system ECU 5. The control device 60 controls the operation of the work vehicle 200 by issuing instructions to other ECUs such as the ECU 73 in the inverter device 72 and the ECU 42 in the FC module 10. Each ECU includes a storage device (ROM) and may also include a processing circuit (or processor) such as an FPGA (Field Programmable Gate Array) and / or a GPU (Graphics Processing Unit). Each ECU executes a computer program stored in the storage device and recording a command group for executing at least one process in sequence, either individually or in cooperation with other ECUs while communicating, and executes the desired action.

[0095] The operation terminal 400 is a terminal for the user to perform operations related to the travel of the work vehicle 200 and the operation of the work tool 300, and is also called a virtual terminal (VT). The operation terminal 400 may include a touch screen display device and / or one or more buttons. The display device may be a display, such as a liquid crystal or an organic light emitting diode (OLED). By operating the touch screen of the operation terminal 400, the user can perform various operations such as inputting information related to the type of the work tool 300 and / or the type of the work, changing the control amount for the work vehicle 200 such as the vehicle speed or the engine speed, switching the power of the work vehicle on / off, and switching the power of the work vehicle on / off. The operation terminal 400 may be configured to be detachable from the work vehicle 200. A user located in a place far away from the work vehicle 200 can also operate the detached operation terminal 400 to control the operation of the work vehicle 200.

[0096] The work vehicle 200 may also include: at least one sensing device for sensing the environment around the work vehicle 200; and a processor for processing sensor data output from the at least one sensing device. The sensing device may include, for example, a plurality of cameras, a LiDAR sensor, and a plurality of obstacle sensors. The sensor data output from the sensing device may be used, for example, for obstacle detection and positioning. It may also be configured so that various ECUs mounted on the work vehicle 200 cooperate with each other and perform calculations and controls for realizing autonomous driving based on the sensor data output from the sensing device.

[0097] In this embodiment, the fuel tank 50 is supported by the fixing frame 120. The fixing frame 120 is fixed to the vehicle body 102 across the driver's seat 107. The fuel tank 50 is located above the driver's seat 107. However, the installation location of the fuel tank 50 is not limited to the example shown in the figure, and may be inside the front housing 110, for example.

[0098] In this embodiment, the fixed frame 120 is a long-axis structure such as a pipe fixed to the vehicle body 102. The fixed frame 120 includes two frames located on the left and right sides of the work vehicle 200 (see Figure 5 ). The front portion of the fixing frame 120 has a curved shape. In addition, the shape of the fixing frame 120 shown in the figure is just an example, and the shape of the fixing frame 120 is not limited to this example.

[0099] In the present embodiment, the vehicle body 102 has: a front frame 102A, which supports the front wheel 104F so as to be rotatable; and a transmission box 102B, which supports the rear wheel 104R so as to be rotatable. One end (front end) of the fixed frame 120 is fixed to the front frame 102A. The other end (rear end) of the fixed frame 120 is fixed to the transmission box 102B. Depending on the material of the fixed frame 120, these fixations can be performed by suitable methods such as welding or bolting. The fixed frame 120 can be formed of, for example, metal, synthetic resin, carbon fiber, or a composite material such as carbon fiber reinforced plastic or glass fiber reinforced plastic. The transmission box 102B includes a rear axle box, and the rear end of the fixed frame 120 can be fixed to the rear axle box. In addition, in the case where the fixed frame 120 is formed of metal, part or all of its surface may also be covered with a synthetic resin.

[0100] like Figure 6As shown, the work vehicle 200 has a cab 105 surrounding a driver's seat 107 between a vehicle body 102 and a fixed frame 120. The driver's seat 107 is located in the rear part of the interior of the cab 105. In front of the driver's seat 107, for example, a steering wheel (steering wheel) 106 for changing the direction of the front wheel 104F is provided. The cab 105 has a cab frame constituting a skeleton. A roof 109 is provided on the upper part of the cab frame. The cab frame of the present embodiment is a four-column type. The cab 105 is supported on the transmission box 102B of the vehicle body 102, for example, via an anti-vibration mount. Refer to Figure 4 The user interface 1 described above is provided inside the cab 105. The cab 105 does not directly support the fuel tank 50, and therefore does not need to be particularly strong, and a cab used for a conventional tractor can be adopted.

[0101] The work vehicle 200 has a mounting platform 51A connecting the left side frame 120 and the right side frame 120. The fuel tank 50 can be arranged on the mounting platform 51A. In the case where there are a plurality of fuel tanks 50, the plurality of fuel tanks 50 can be arranged in the fuel tank module 55. Figure 6 As shown, the fuel tank module 55 includes a tank case 51 that accommodates a plurality of fuel tanks 50. The left and right fixing frames 120 may be connected to each other by a member other than the mounting table 51A.

[0102] A connection device 108 is provided at the rear portion of the vehicle body 102, i.e., the rear end of the transmission box 102B. The connection device 108, for example, includes a three-point support device (also called a "three-point link" or a "three-point hook"), a PTO shaft, a universal joint, and a communication cable. The connection device 108 can be used to load and unload the working tool 300 relative to the working vehicle 200. The connection device 108 can, for example, raise and lower the three-point link through a hydraulic device to change the position or posture of the working tool 300. In addition, power can be transmitted from the working vehicle 200 to the working tool 300 via the universal joint. The working vehicle 200 can tow the working tool 300 and enable the working tool 300 to perform a specified operation (agricultural operation). The connection device 108 can also be provided at the front portion of the vehicle body 102. In this case, the working tool 300 can be connected in front of the working vehicle 200.

[0103] The working tool 300 has, for example, a drive device, a control device, and a communication device. The drive device performs the actions required for the working tool 300 to perform a specified operation. The drive device includes, for example, a hydraulic device, an electric motor, or a pump, which is corresponding to the purpose of the working tool 300. The control device controls the actions of the drive device. The control device causes the drive device to perform various actions in response to a signal sent from the working vehicle 200 via the communication device. In addition, a signal corresponding to the state of the working tool 300 can also be sent from the communication device to the working vehicle 200.

[0104] Figure 6 The working tool 300 shown is a rotary tiller, but the working tool 300 is not limited to a rotary tiller. For example, any working tool such as a planter (seeder), a spreader (fertilizer), a transplanter, a mower (mower), a spiked harrow, a baler (grass collector), a harvester (reaper), a sprayer or a rake can be connected to the working vehicle 200 for use.

[0105] Figure 6 The work vehicle 200 shown can be driven by a person, but can also be driven by an unmanned person. In this case, the structural elements required for human driving, such as the cab 105, the steering wheel 106, and the driver's seat 107, may not be provided on the work vehicle 200. The unmanned work vehicle 200 can be driven autonomously or by remote control of the user.

[0106] (4.2. Discharge processing when operation stops)

[0107] When the control device 60 of the work vehicle 200 issues a command to stop the operation of the work vehicle 200, the control device 60 stops the operation of the FC module 10 and performs a discharge process to consume the residual charge of the circuit group in the system. Figure 7 An example of this processing will be described.

[0108] Figure 7 2 is a flowchart showing an example of the operation of the control device 60 when the operation of the work vehicle 200 is stopped. The control device 60 executes Figure 7 The operation of work vehicle 200 is stopped by performing the operations of steps S110 to S150 shown.

[0109] In step S110, the control device 60 determines whether an instruction to stop the operation is issued. The instruction to stop the operation is an instruction to stop the power supply to each electrical component of the work vehicle 200 and the power generation of the fuel cell. For example, when the user turns off the power switch (for example, the ignition switch) included in the operating device 2, the instruction to stop the operation can be issued. When the instruction to stop the operation is issued, the process proceeds to step S120.

[0110] In step S120, the control device 60 stops supplying the oxidizing gas (e.g., air) to the FC module 10. Specifically, in response to the instruction to stop the operation, the FC system ECU 5 of the control device 60 instructs the ECU 42 of the FC module 10 to close the shutoff valve 17 (see Figure 2). As a result, the flow of oxidizing gas to the FC stack 11 is cut off, and power generation is stopped. In addition, in the present embodiment, the supply of oxidizing gas to the FC stack 11 is stopped, but the system may be configured to stop the supply of fuel (hydrogen in the present embodiment) instead. In step S120, the control device 60 also stops the operation of the air compressor 12.

[0111] Next, in step S130, the control device 60 stops the power transmission from the motor 70 to the travel device. Specifically, the main ECU 3 of the control device 60 switches the plurality of clutches in the power transmission system 74 from the connected state to the disconnected state, and stops the power transmission from the motor 70 to the travel device including the axle and the wheel 104. At this time, the main ECU 3 may connect the PTO clutch to maintain the power transmission from the motor 70 to the PTO shaft 76, or may disconnect the PTO clutch to stop the power transmission from the motor 70 to the PTO shaft 76.

[0112] Next, in step S140, the control device 60 rotates the motor 70 to discharge the residual charge in the circuit group connected to the motor 70. Specifically, the main ECU 3 in the control device 60 consumes the residual charge by issuing a command to the ECU 73 in the inverter device 72 to rotate the motor 70. At this time, the motor 70 rotates, but the power transmission from the motor 70 to the travel device is stopped, so the travel device remains stopped. While maintaining the power transmission from the motor 70 to the PTO shaft 76, the PTO shaft 76 also rotates as the motor 70 rotates. By rotating the PTO shaft 76, the consumed energy can be increased compared to the case where the PTO shaft 76 is not rotated. As a result, the time required for discharge can be shortened. On the other hand, when the power transmission from the motor 70 to the PTO shaft 76 is stopped, the PTO shaft 76 does not rotate even if the motor 70 rotates. In this case, the consumed energy becomes relatively small, but when the operation of the work vehicle 200 is stopped, it is possible to avoid the work tool 300 connected to the PTO shaft 76 from being driven unnecessarily.

[0113] When the residual charge is discharged, the process proceeds to step S150, and control device 60 stops the operation of motor 70 and other electrical components. Thus, the operation of work vehicle 200 stops.

[0114] Through the above-mentioned discharge process, the residual charge of the circuit group connected to the motor 70 is consumed. Figure 4The bridge circuit, boost circuit 40, and DC-DC converters 81, 82 in the inverter device 72 shown. The boost circuit 40 functions as a boost converter that boosts the DC voltage generated by the FC stack 11. The bridge circuit in the inverter device 72 functions as an inverter that converts the DC voltage output from the boost converter into an AC voltage and supplies it to the motor 70. These circuits may include a plurality of capacitors (capacitors). By discharging, the charge remaining in these capacitors can be discharged. Thus, it is possible to prevent unnecessary charge from remaining in the circuit when the power supply of the work vehicle 200 is disconnected.

[0115] In the discharge process of step S140, the control device 60 may not only rotate the motor 70, but also operate other electrical components or charge the battery 80 to discharge the residual charge. For example, the control device 60 may stop the supply of fuel or oxidizing gas to the FC module 10 and then discharge the residual charge. Figure 4 The air cooling fan (cooling fan) in the radiator device 34A for cooling the FC stack 11 shown in the figure is rotated to discharge the residual charge in the circuit in the FC module 10. By rotating not only the motor 70 but also the cooling fan for cooling the FC module 10, the residual charge in the FC module 10 can be effectively discharged. In addition, the control device 60 can also rotate the cooling fan in the radiator device 34B for cooling the electrical components other than the FC stack 11 in response to the instruction to stop the operation, so as to discharge the residual charge remaining in the DC-DC converter 81, etc. In addition, the control device 60 can also be configured to consume the residual charge more effectively by operating the hydraulic system including the hydraulic pump. However, when the hydraulic pump is operated, the hydraulic locking mechanism can be used to prevent the lifting arm, etc. in the connecting device 108 from operating.

[0116] like Figure 3 and Figure 4 As shown, the working vehicle 200 of the present embodiment may further include a first switch R1 provided on the current path between the FC module 10 and the motor 70. The working vehicle 200 may further include a second switch R2 provided on the current path between the battery 80 and the motor 70. The first switch R1 and the second switch R2 may be, for example, relays. The control of turning on / off of each of the first switch R1 and the second switch R2 may be performed by the main ECU 3 in the control device 60. By turning off the first switch R1, the power supply from the FC module 10 to the motor 70 is cut off. By turning off the second switch R2, the power supply from the battery 80 to the motor 70 is cut off.

[0117] The control device 60 may also open the first switch R1 in response to the instruction to stop the operation, and then discharge the residual charge by rotating the motor 70 or operating other electrical components. At this time, the control device 60 may also operate other electrical components such as cooling fans in the radiator devices 34A and 34B. By opening the first switch R1, the residual charge can be discharged in a state where the power supply from the FC module 10 to the motor 70 is cut off. The control device 60 may also open the first switch and the second switch in response to the instruction to stop the operation, and then discharge the residual charge by rotating the motor 70 or operating other electrical components. In this way, the residual charge can be discharged in a state where the power supply from the FC module 10 and the battery 80 to the motor 70 is cut off.

[0118] Figure 8 This is a flowchart showing an example of an operation of discharging residual electric charge by operating the motor and other electrical components in a state where the switches R1 and R2 are turned off. Figure 8 The flowchart shown in the figure Figure 7 Except that step S140 in the above is replaced by steps S240 and S250, Figure 7 The flowchart shown is the same. Figure 8 In the example of FIG. 1 , after stopping the power transmission from the motor 70 to the travel device in step S130, the process proceeds to step S240, and the control device 60 turns off the first switch R1 and the second switch R2. Next, in step S250, the control device 60 operates the motor 70 and other electrical components (for example, the cooling fan in the radiator device 34A, 34B, the hydraulic system and / or the electric pump, etc.) to discharge the residual charge. Through such an operation, the peripheral circuits of the motor 70 and the circuits in the FC module 10 can be effectively discharged.

[0119] The control device 60 may also change the discharge process when the working tool 300 is connected to the PTO shaft 76 and when it is not connected to the PTO shaft 76. For example, the control device 60 may rotate the motor 70 in a state where the power transmission from the motor 70 to the PTO shaft 76 is stopped when the working tool 300 is connected to the PTO shaft 76, and rotate the motor 70 in a state where the power transmission from the motor 70 to the PTO shaft 76 is maintained when the working tool 300 is not connected to the PTO shaft 76. By such control, the discharge method can be appropriately switched according to the presence or absence of the working tool 300.

[0120] Fig. 9 This is a flowchart showing an example of the operation of changing the discharge process according to whether the working tool 300 is connected to the PTO shaft 76 . Fig. 9 The flowchart shown is Figure 8The example is the same as step S8 except that steps S241, S242, and S243 are added between steps S240 and S250. Fig. 9 In the example of FIG. 2 , after the switches R1 and R2 are turned off in step S240, the control device 60 determines whether the working tool is connected to the PTO shaft 76. For example, it is possible to determine whether the working tool 300 is connected to the PTO shaft 76 based on a signal sent from the working tool 300 to the working vehicle 200. If the working tool is connected, the process proceeds to step S242. If the working tool is not connected, the process proceeds to step S243.

[0121] In step S242, the control device 60 turns the PTO clutch into the disconnected state, thereby stopping the power transmission from the motor 70 to the PTO shaft 76.

[0122] In step S243 , the control device 60 connects the PTO clutch, thereby maintaining the power transmission from the motor 70 to the PTO shaft 76 .

[0123] In the next step S250, the control device 60 operates the motor 70 and other electrical components to discharge the residual charge. Then, in step S150, the operation of the motor 70 and other electrical components is stopped. Thus, the operation of the work vehicle 200 is stopped.

[0124] according to Fig. 9 The control shown can prevent the work tool 300 from operating due to unnecessary rotation of the PTO shaft 76 when the work tool 300 is connected to the work vehicle 200 and the operation of the work vehicle 200 is stopped. On the other hand, when the work tool 300 is connected to the work vehicle 200, the PTO shaft is rotated to increase the energy consumed, and discharge can be performed more efficiently. In this way, an appropriate discharge method can be selectively performed according to the presence or absence of the work tool 300.

[0125] In each of the above-mentioned embodiments, the discharge process is performed when a command is issued to turn off the power of the work vehicle 100. The timing is not limited to the power off timing, and the same discharge process may be performed when a command is issued to stop the FC module 10 (temporary stop of the FC module 10). By performing the discharge process during the idling stop, the degradation of the fuel cell can be suppressed.

[0126] The configurations and operations of the above-described embodiments are merely illustrative, and the present disclosure is not limited to the above-described embodiments. For example, the above-described various embodiments may be appropriately combined to form other embodiments.

[0127] As described above, the present disclosure includes the work vehicle, the control device for the work vehicle, and the control method for the work vehicle described in the following items.

[0128] [Project 1]

[0129] A working vehicle, wherein

[0130] have:

[0131] A fuel cell module having a fuel cell stack;

[0132] at least one fuel tank for containing fuel supplied to the fuel cell stack;

[0133] a motor connected to the fuel cell module;

[0134] a traveling device, driven by the motor;

[0135] a power output shaft, driven by the motor and connected to a working tool; and

[0136] Control device,

[0137] The control device stops the supply of the fuel or oxidant gas to the fuel cell stack in response to an instruction to stop the operation, and then rotates the motor while stopping the power transmission from the motor to the driving device to discharge the residual charge in the circuit group connected to the motor.

[0138] [Project 2]

[0139] The work vehicle according to item 1, wherein:

[0140] The control device performs the discharge by rotating the motor while maintaining power transmission from the motor to the power output shaft.

[0141] [Item 3]

[0142] The work vehicle according to item 1, wherein:

[0143] The control device performs the discharge by rotating the motor in a state where power transmission from the motor to the power output shaft is stopped.

[0144] [Item 4]

[0145] A work vehicle according to any one of items 1 to 3, wherein:

[0146] The working vehicle further includes a first switch, which is provided on a current path between the fuel cell module and the motor.

[0147] The control device turns off the first switch in response to the instruction to stop the operation, and then performs the discharge by rotating the motor.

[0148] [Item 5]

[0149] The work vehicle according to item 4, wherein:

[0150] The working vehicle also has:

[0151] a battery connected to the fuel cell module and the motor; and

[0152] a second switch, disposed on a current path between the battery and the motor,

[0153] The control device turns off the first switch and the second switch in response to the instruction to stop the operation, and then performs the discharge by rotating the motor.

[0154] [Item 6]

[0155] A work vehicle according to any one of items 1 to 5, wherein:

[0156] The circuit group comprises:

[0157] a boost converter for boosting a DC voltage generated by the fuel cell stack; and

[0158] The inverter converts the DC voltage output from the boost converter into an AC voltage and supplies the AC voltage to the motor.

[0159] [Item 7]

[0160] A work vehicle according to any one of items 1 to 6, wherein:

[0161] The working vehicle further comprises a cooling fan, and the cooling fan is used to cool the fuel cell module.

[0162] The control device stops supply of the fuel or oxidant gas to the fuel cell module in response to the command to stop operation, and then further rotates the cooling fan to discharge residual charge in the fuel cell module.

[0163] [Item 8]

[0164] A work vehicle according to any one of items 1 to 7, wherein:

[0165] The working vehicle is an agricultural machine.

[0166] [Item 9]

[0167] A control device for a working vehicle, the working vehicle comprising: a fuel cell module having a fuel cell stack; at least one fuel tank for containing fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a travel device driven by the motor; a power output shaft driven by the motor and connected to a working tool, wherein:

[0168] The control device stops the supply of the fuel or oxidant gas to the fuel cell module in response to an instruction to stop the operation, and then rotates the motor in a state where the power transmission from the motor to the driving device is stopped to discharge the residual charge in the circuit group connected to the motor.

[0169] [Item 10]

[0170] A control method for a working vehicle, the working vehicle comprising: a fuel cell module having a fuel cell stack; at least one fuel tank containing fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a travel device driven by the motor; a power output shaft driven by the motor and connected to a working tool, wherein:

[0171] The control method comprises:

[0172] In response to an instruction to stop operation, stopping the supply of the fuel or oxidizing gas to the fuel cell module; and

[0173] After the supply of the fuel is stopped, the motor is rotated in a state where power transmission from the motor to the travel device is stopped, thereby discharging residual electric charge in a circuit group connected to the motor.

[0174] Industrial Applicability

[0175] The technology disclosed in the present invention can be applied to work vehicles such as agricultural tractors, harvesters, rice transplanters, passenger training machines, and vegetable transplanters, for example.

[0176] Description of reference numerals:

[0177] 1 user interface, 2 operation device, 3 main ECU, 4 main instrument, 5 FC system ECU, 6 FC instrument, 7 storage device, 10 fuel cell module, 11 FC stack, 40 boost circuit, 34 radiator device, 40 boost circuit, 42, control device (ECU), 50 fuel tank, 51 tank box, 60 control device, 70 motor, 71 output shaft, 72 inverter device, 74 power transmission system, 76 power output (PTO) shaft, 80 battery pack, 81 first DC-DC converter, 82 second DC-DC converter, 83 storage battery, 85 refrigeration compressor, 86 heater, 100 work vehicle, 102 vehicle body, 102A front frame, 102B transmission box, 104 wheel, 104F front wheel, 104R rear wheel, 107 driver's seat, 120 fixed frame.

Claims

1. A working vehicle, wherein: have: A fuel cell module having a fuel cell stack; at least one fuel tank for containing fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a traveling device, driven by the motor; A power output shaft, driven by the motor and connected to a working tool; as well as Control device, The control device stops the supply of the fuel or oxidant gas to the fuel cell stack in response to an instruction to stop the operation, and then rotates the motor while stopping the power transmission from the motor to the driving device to discharge the residual charge in the circuit group connected to the motor.

2. The work vehicle according to claim 1, wherein: The control device performs the discharge by rotating the motor while maintaining power transmission from the motor to the power output shaft.

3. The work vehicle according to claim 1, wherein: The control device performs the discharge by rotating the motor in a state where power transmission from the motor to the power output shaft is stopped.

4. The working vehicle according to any one of claims 1 to 3, wherein: The working vehicle further includes a first switch, which is provided on a current path between the fuel cell module and the motor. The control device turns off the first switch in response to the instruction to stop the operation, and then performs the discharge by rotating the motor.

5. The work vehicle according to claim 4, wherein: The working vehicle also has: a battery connected to the fuel cell module and the motor; and a second switch, disposed on a current path between the battery and the motor, The control device turns off the first switch and the second switch in response to the instruction to stop the operation, and then performs the discharge by rotating the motor.

6. The working vehicle according to any one of claims 1 to 3, wherein: The circuit group comprises: a boost converter for boosting a DC voltage generated by the fuel cell stack; and The inverter converts the DC voltage output from the boost converter into an AC voltage and supplies the AC voltage to the motor.

7. The working vehicle according to any one of claims 1 to 3, wherein: The working vehicle further comprises a cooling fan, and the cooling fan is used to cool the fuel cell module. The control device stops supply of the fuel or oxidant gas to the fuel cell module in response to the command to stop operation, and then further rotates the cooling fan to discharge residual charge in the fuel cell module.

8. The working vehicle according to any one of claims 1 to 3, wherein: The working vehicle is an agricultural machine.

9. A control device for a working vehicle, the working vehicle comprising: a fuel cell module having a fuel cell stack; at least one fuel tank containing fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a travel device driven by the motor; a power output shaft driven by the motor and connected to a working tool, wherein: The control device stops the supply of the fuel or oxidant gas to the fuel cell module in response to an instruction to stop the operation, and then rotates the motor in a state where the power transmission from the motor to the driving device is stopped to discharge the residual charge in the circuit group connected to the motor.

10. A control method for a work vehicle, the work vehicle comprising: a fuel cell module having a fuel cell stack; at least one fuel tank containing fuel supplied to the fuel cell stack; a motor connected to the fuel cell module; a traveling device, driven by the motor; The power output shaft is driven by the motor and connected to a working tool, wherein: The control method comprises: In response to an instruction to stop operation, stopping the supply of the fuel or oxidizing gas to the fuel cell module; and After the supply of the fuel is stopped, the motor is rotated in a state where power transmission from the motor to the travel device is stopped, thereby discharging residual electric charge in a circuit group connected to the motor.

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