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; the power output shaft is driven by the motor and is connected with a working tool; and a control device. The control device is capable of operating in a plurality of control modes. The plurality of control modes include a normal mode and an output limiting mode in which an upper limit value of power supplied from the fuel cell module to the motor is smaller than that in the normal mode. The control device changes the upper limit value of the electric power supplied to the motor in the output restriction mode in accordance with the type of the work tool connected to the power output shaft and / or the type of work performed by the work tool.

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 achieve 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. Unlike general cars, work vehicles such as tractors need to tow work machines called work tools to perform agricultural operations such as tilling. Therefore, in order to achieve 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 work vehicle that is equipped with a fuel cell (Fuel Cell: FC) and is driven by electric power generated by the fuel cell.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-136970 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In a work vehicle equipped with a fuel cell module, there are cases where the output of the motor needs to be suppressed, such as when the remaining amount of fuel is low or when the fuel cell module or the motor reaches a high temperature.

[0010] The present disclosure provides a technology for appropriately limiting the output of a motor under a situation where it is necessary to suppress the output of the motor.

[0011] Means used to solve problems

[0012] In an exemplary non-limiting embodiment, a working vehicle of one embodiment of the present disclosure comprises: 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 power output shaft driven by the motor and connected to a working tool; and a control device that controls the power supplied from the fuel cell module to the motor. The control device is capable of operating in a plurality of control modes. The plurality of control modes include a normal mode and an output limiting mode, in which the upper limit value of the power supplied from the fuel cell module to the motor is smaller than that in the normal mode. The control device changes the upper limit value of the power supplied to the motor in the output limiting mode according to the type of the working tool connected to the power output shaft and / or the type of work performed by the working tool.

[0013] 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.

[0014] Effects of the Invention

[0015] According to the embodiment of the present disclosure, in a situation where it is necessary to suppress the motor output, the motor output can be appropriately limited according to the type of the power tool and / or the type of work. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a plan view schematically showing a basic configuration example of a work vehicle according to the present disclosure.

[0017] Figure 2 This is a diagram showing a basic configuration example of a fuel cell power generation system mounted on a work vehicle.

[0018] 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.

[0019] 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.

[0020] Figure 5 It is a perspective view schematically showing a configuration example of a work vehicle in an embodiment of the present disclosure.

[0021] Figure 6 It is a side view schematically showing a configuration example of a work vehicle in an embodiment of the present disclosure.

[0022] Fig. 7A This is a diagram showing an example of a table indicating the relationship between the type of power tool and the upper limit value of the power supplied to the motor.

[0023] Figure 7B This is a diagram showing an example of a table indicating the relationship between the type of power tool, the type of work, and the upper limit value of the electric power supplied to the motor.

[0024] Figure 7C This is a diagram showing another example of a table indicating the relationship between the type of power tool, the type of work, and the upper limit value of the electric power supplied to the motor.

[0025] Figure 8 This is a flowchart showing an example of the operation executed by the control device.

[0026] Fig. 9 A diagram schematically showing an example of display on a display device.

[0027] Fig.10 This is a diagram schematically showing another example of display on the display device. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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."

[0031] 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.

[0032] 1. <Basic structure of work vehicle>

[0033] 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.

[0034] 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”.

[0035] 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.

[0036] 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.

[0037] 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".

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] In the working vehicle 100 in the embodiments described below, a driver's seat is supported by the 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 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 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 the influence of 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.

[0044] 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 portion (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.

[0045] 2. <FC Power Generation System>

[0046] Next, with reference to Figure 2 , a basic structural example of the FC power generation system 180 mounted on the working vehicle 100 will be described.

[0047] Figure 2 The FC power generation system 180 shown functions as an in-vehicle power generation system in the Figure 1 working 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 working vehicle 100 but also for the operation of the working tools towed or mounted by the working vehicle 100.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In the anode, an electrochemical reaction represented by the following formula (1) occurs.

[0053] 2H2→4H + +4e - …Formula (1)

[0054] In the cathode, an electrochemical reaction represented by the following formula (2) occurs.

[0055] 4H + +4e - +O2→2H2O…Formula (2)

[0056] As a whole, the reaction of the following formula (3) occurs.

[0057] 2H2+O2→2H2O…Formula (3)

[0058] 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".

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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”.

[0071] 3.<System configuration example of work vehicle>

[0072] 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.

[0073] 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.

[0074] 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 (hereinafter, also referred to as an "inverter 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 rotation speed controlled according to the waveform of the three-phase AC voltage from the inverter device 72.

[0075] 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.

[0076] 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 1 wheels 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 purposes 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; and a PTO system power transmission mechanism that transmits power from the motor 70 to the PTO shaft 76. Figure 1The transmission case 102B can also be divided into a front case (transmission case) containing a clutch and a transmission, etc., and a rear case (differential gear case) containing a rear wheel differential device, etc. The rear case is also called a rear axle case.

[0077] 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 can supply electric 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 adopted.

[0078] 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.

[0079] exist Figure 3 In 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.

[0080] 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 3Although 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 .

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] The fuel tank 50 is provided with a sensor S4 for measuring the remaining amount of fuel in the fuel tank 50. In addition, a temperature sensor for measuring the temperature in the fuel tank 50 may be provided. Examples of the sensor S4 include a pressure sensor for measuring the pressure of the fuel corresponding to the remaining amount of the fuel. The pressure sensor acquires residual pressure data indicating the residual pressure of the fuel in the fuel tank 50.

[0087] 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).

[0088] 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.

[0089] exist Figure 4 In 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 4In 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 .

[0090] The user interface 1 includes an operating device 2 such as an accelerator pedal (or an accelerator lever), a sound output device 8 , 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 .

[0091] The main ECU 3 is connected to the FC system ECU 5, the operating device 2, the sound output device 8, 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.

[0092] 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.

[0093] An example of the sound output device 8 is a buzzer or a speaker. The sound output device 8 can be controlled by the main ECU 3. The sound output device 8 outputs a sound urging fuel refueling, for example.

[0094] The cells of the battery pack 80 are controlled by a battery management unit (BMU). The BMU has a temperature sensor such as a thermistor for measuring the temperature of the cell, a voltage monitor for each cell, 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.

[0095] exist Figure 4 In the example shown, the inverter device 72 includes a temperature sensor S5. The temperature sensor S5 measures the temperature of the inverter device 72. In addition, a temperature sensor S6 is provided near the motor 70. The temperature sensor S6 measures the temperature of the motor 70.

[0096] 4. <Implementation Method>

[0097] (4.1. Basic structure of work vehicle)

[0098] 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.

[0099] like Figure 6 As shown, the working vehicle 200 in this embodiment includes the FC module 10, the fuel tank 50, and the sensor S4 (see Figure 3 or Figure 4 ), motor 70, driver's seat 107, control device 60, operation terminal 400 and 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.

[0100] The operation terminal 400 is a terminal for the user to perform operations related to the travel of the work vehicle 200 and the action 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, and switching the on / off of the work tool. The touch screen of the operation terminal 400 has the functions of both a display device and an input device. 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 may also operate the detached operation terminal 400 to control the action of the work vehicle 200. In addition, an input device and a display device different from the operation terminal 400 may also be used. For example, a computer such as a personal computer (PC), a laptop computer, a tablet computer, a smart phone, or its peripheral devices may also be used as an input device and a display device. in addition, Figure 4 The instruments 4 , 6 shown also function as display devices.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] like Figure 6 As 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] (4.2. Operation in output limit mode)

[0112] The control device 60 controls the operation of the work vehicle 200. For example, the control device 60 controls the power supplied from the FC module 10 to the motor 70. Figure 4As shown, the power output from the FC module 10 is supplied to the motor 70 via the inverter device 72. The control device 60 can control the power supplied to the motor 70 by, for example, issuing a command to the ECU 42 to change the amount of power generated by the FC module 10, or issuing a command to the ECU 73 of the inverter device 72 to change the output power of the inverter circuit. There is a relationship between the power supplied to the motor 70 (i.e., the input power of the motor 70) and the mechanical output of the motor 70 (hereinafter referred to as "the output of the motor 70" or "the motor output"): input power = mechanical output + loss. Therefore, the control device 60 can control the output of the motor 70 by controlling the power supplied from the FC module 10 to the motor 70.

[0113] The control device 60 in this embodiment can operate in a plurality of control modes. The plurality of control modes include a normal mode and an output limiting mode. The output limiting mode is a mode in which the output of the motor 70 is limited in order to suppress fuel consumption or suppress the temperature rise of the device. In the output limiting mode, the fuel consumption is suppressed, so the output limiting mode can also be called an "economy mode". The control device 60 can be configured to switch from the normal mode to the output limiting mode, for example, when the remaining amount of fuel in the fuel tank 50 is small, or when the temperature of the device such as the FC module 10, the inverter device 72 or the motor 70 becomes high. In the output limiting mode, the upper limit value of the power supplied from the FC module 10 to the motor 70 and the upper limit value of the output of the motor 70 are limited in a manner smaller than in the normal mode. This control can be achieved, for example, by limiting the amount of power generation by suppressing the amount of fuel or oxidizing gas supplied to the FC stack 11, or by limiting the output power of the inverter circuit by switching control of the inverter circuit. In the output limiting mode, for example, even if the accelerator pedal is stepped on strongly, the vehicle speed may not increase much.

[0114] The control device 60 in this embodiment is configured to change the upper limit of the power supplied to the motor 70 in the output limiting mode according to the type of the working tool 300 connected to the PTO shaft 76 and / or the type of work performed by the working tool 300. Figure 4 When the remaining amount of fuel in the fuel tank 50 measured by the sensor S4 shown in FIG. 1 is lower than the threshold value, the control device 60 is switched from the normal mode to the output restriction mode. Alternatively, the control device 60 may be configured to Figure 2When the temperature of the coolant of the FC module 10 measured by the temperature sensor S3 shown in the figure exceeds a threshold value (e.g., 90°C or 100°C, etc.), the mode is shifted from the normal mode to the output restriction mode. Conversely, the control device 60 may also shift from the normal mode to the output restriction mode when the temperature of the FC module 10 measured by the temperature sensor S3 is lower than another threshold value (e.g., 0°C or -10°C, etc.). In addition, not limited to the temperature of the FC module 10, for example, the mode may shift from the normal mode to the output restriction mode when the temperature measured by the temperature sensor S5 of the inverter device 72 or the temperature sensor S6 of the motor 70 exceeds a threshold value. Alternatively, the mode may shift from the normal mode to the output restriction mode when the temperature obtained from a sensor measuring the temperature of a device or a measuring circuit other than the FC module 10, the inverter device 72, and the motor 70 exceeds a threshold value.

[0115] As described above, the type of working tool is, for example, a rotary machine, a seed drill or a spreader. The type of work performed by the working tool is tillage, sowing or fertilization. In addition, the type of working tool and the type of work may not necessarily correspond one-to-one. For example, in the case where the type of working tool is a rotary machine, the type of work may include a plurality of types such as tillage, harrowing or ridging. Even when performing the same type of work, there may be a situation where the load of the work is different depending on the situation. For example, even when the same working tool is used to perform the same work, the rotation speed of the PTO shaft 76 may be changed according to the state of the work site, etc. In such a case, the control device 60 may also change the upper limit of the power supplied to the motor 70 according to the load of the work.

[0116] The control device 60 obtains identification information of the working tool 300 from the working tool 300 connected to the PTO shaft 76, and determines the type of the working tool 300 based on the identification information. The working vehicle 200 and the working tool 300 can communicate in accordance with ISOBUS standards such as ISOBUS-TIM. In this way, the control device 60 of the working vehicle 200 can obtain the identification information of the working tool 300 by communicating with the working tool 300. Alternatively, the control device 60 can also determine the type of the working tool 300 connected to the PTO shaft 76 and / or the type of the operation performed by the working tool 300 based on information related to the type of the working tool 300 and / or the type of the operation input by the user via an input device such as an operation terminal 400.

[0117] Figure 4The sensor S4 shown acquires the remaining pressure data of the fuel in the fuel tank 50. The control device 60 can estimate the remaining amount of fuel based on the remaining pressure data output from the sensor S4. In the present embodiment, the remaining amount of fuel estimated in this way is sometimes referred to as the remaining amount of fuel measured by the sensor S4. The remaining amount of fuel can also be expressed by the ratio (%) of the remaining amount to the tank capacity in the full tank state. The control device 60 can be configured to determine whether it is necessary to shift from the normal mode to the output restriction mode based on the remaining amount of fuel measured by the sensor S4.

[0118] Figure 2 The temperature sensor S3 shown measures the temperature of the coolant flowing in the coolant discharge pipe 33. The control device 60 may be configured to use the temperature measured by the temperature sensor S3 as the temperature of the FC module 10, and determine whether it is necessary to shift from the normal mode to the output restriction mode based on the temperature. For example, when the temperature measured by the temperature sensor S3 deviates from a preset temperature range, it is possible to shift from the normal mode to the output restriction mode. The temperature of the FC module 10 may be measured by a temperature sensor other than the temperature sensor S3 that measures the temperature of the coolant flowing in the coolant discharge pipe 33. In addition, a temperature sensor S5 that measures the temperature of the inverter device 72 or a temperature sensor S6 that measures the temperature of the motor 70 may be used. In this case, the control device 60 may be configured to determine whether it is necessary to shift from the normal mode to the output restriction mode based on the measured temperature of the inverter device 72 or the motor 70.

[0119] Figure 4 The storage device 7 shown stores data that specifies the correspondence between the type of work tool and / or the type of work and the upper limit of the power supplied from the FC module 10 to the motor 70. The control device 60 may be configured to determine the upper limit of the power supplied from the FC module 10 to the motor 70 or the motor output based on the data. The data may be, for example, a lookup table (hereinafter referred to as a "table").

[0120] Fig. 7A 2 is a diagram showing an example of a table indicating the relationship between the type of working tool and the upper limit value of the electric power supplied to the motor 70 (that is, the input electric power of the motor 70). Fig. 7AIn the example of the table shown, the types of working tools include five types: rotary machine, spreader, sowing machine, mower and rake. In the table, the upper limit value of the corresponding power is recorded for each type of working tool. For example, when the working tool 300 installed on the working vehicle 200 is a rotary machine, the upper limit value of the power supplied to the motor 70 is P1 (kW), and when the working tool 300 is a spreader, the upper limit value of the power is P2 (kW). In this example, the upper limit value of the power supplied to the motor 70 can be set to different values ​​according to the type of the working tool 300.

[0121] Figure 7B 2 is a diagram showing an example of a table showing the relationship between the type of working tool, the type of work, and the upper limit value of the electric power supplied to the motor 70. Figure 7B In the example of the table shown, the types of working tools include five types, namely, a rotary machine, a spreader, a seed drill, a mower, and a harrow, and the types of operations include seven types, namely, tillage, harrowing, ridging, fertilizing, seeding, mowing, and crushing. In the table, the upper limit value of the corresponding electric power is recorded for each group of the type of working tool and the type of operation. For example, when the working vehicle 200 is performing tillage operations while towing a rotary machine, the upper limit value of the electric power supplied to the motor 70 is P11 (kW), and when the working vehicle 200 is performing fertilization operations while towing a spreader, the upper limit value of the electric power is P21 (kW). In this example, the upper limit value of the electric power supplied to the motor 70 differs depending on the type of working tool 300, and may also be set to different values ​​depending on the type of operation. In addition, it is also possible to use the upper limit value from Figure 7B The table shown excludes the information on the type of the working tool. In this case, the upper limit of the electric power supplied to the motor 70 can be set to a different value depending on the type of work.

[0122] Figure 7C 2 is a diagram showing another example of a table showing the relationship between the type of power tool, the type of work, and the upper limit value of the power supplied to the motor 70. Figure 7C In the table shown, tillage work performed by rotary machines is classified into three levels according to the size of the load. Figure 7B For example, when the work vehicle 200 is pulling a rotary machine while performing a heavy-load tillage operation, the upper limit of the power supplied to the motor 70 is P111 (kW), when the work vehicle 200 is performing a medium-load tillage operation, the upper limit of the power is P112 (kW), and when the work vehicle 200 is performing a light-load tillage operation, the upper limit of the power is P113 (kW). As in this example, the type of operation can also be classified into multiple levels according to the load of the operation.

[0123] The control device 60 in this embodiment can refer to Fig. 7A , Figure 7B or Figure 7C The table shown as an example is used to determine the upper limit of the power corresponding to the type of the working tool 300 connected to the PTO shaft 76 and / or the type of work. In the output limiting mode, the control device 60 limits the power supplied to the motor 70 in such a way that the power does not exceed the upper limit of the power determined. For example, when the user operates the accelerator pedal or accelerator lever included in the operating device 2 to issue an acceleration instruction, or issues an instruction to increase the rotation speed of the PTO shaft 76, and the upper limit of the power is exceeded, the control device 60 limits the power to below the upper limit. As a result, the motor output is limited, and the fuel consumption and the heating of the equipment can be suppressed.

[0124] During operation of work vehicle 200, control device 60 may display information indicating whether the current mode is the normal mode or the output restriction mode on a display device such as operation terminal 400. In the output restriction mode, the display device may display information indicating that the motor output is actually restricted.

[0125] The work vehicle 200 has a battery ( Figure 4 The control device 60 may also determine whether to charge the battery in the output restriction mode, and in the case of charging, increase the power output from the FC module 10 compared to the case of not charging. For example, in the case of charging, the power output from the FC module 10 may be increased by the amount of power required for charging compared to the case of not charging. The control device 60 may be configured to determine whether to charge the battery based on at least one of the battery's charge rate (State of Charge: SOC) and the battery's temperature.

[0126] Figure 8 This is a flowchart showing an example of the operation executed by the control device 60 . Figure 8 The operation shown is started when work vehicle 200 is operating in the normal mode. Figure 8 In the example shown, the control device 60 first acquires measurement data from a plurality of sensors in the work vehicle 200. For example, the control device 60 may be configured to acquire data indicating the remaining amount of fuel measured by the sensor S4 of the fuel tank 50, data indicating the temperature of the FC module 10 measured by the temperature sensor S3 of the FC module 10, and data indicating the battery charge rate (SOC) and the temperature of the battery cells measured by the BMU of the battery pack 80. The control device 60 may also acquire temperature data measured by the temperature sensor S5 of the inverter device 72 or the temperature sensor S6 of the motor 70.

[0127] In the next step S120, the control device 60 determines whether to start the output restriction mode based on the acquired data. For example, the control device 60 may be configured to determine that the output restriction mode is started when the remaining amount of fuel measured by the sensor S4 is lower than the first threshold. When the sensor S4 is a pressure sensor that measures the internal pressure in the fuel tank 50, it may be determined that the remaining amount of fuel is lower than the first threshold when the measured pressure is lower than a predetermined threshold. The control device 60 may also determine that the output restriction mode is started when the temperature of the FC module 10 measured by the temperature sensor S3 exceeds a second threshold, based on the determination based on the remaining amount of fuel, or instead of the determination. The second threshold may be set to an upper limit value of an appropriate temperature range of the FC module 10, such as 80°C, 90°C, or 100°C, or a value close thereto. In addition, the control device 60 may determine that the output restriction mode is started when the temperature of the FC module 10 measured by the temperature sensor S3 is lower than a third threshold that is smaller than the second threshold. The third threshold may be set to a lower limit value of an appropriate temperature range, such as 0°C, -10°C, or -20°C, or a value close thereto. Alternatively, the control device 60 may determine to start the output limiting mode when the temperature of the inverter device 72 measured by the temperature sensor S5 or the temperature of the motor 70 measured by the temperature sensor S6 is out of the respective appropriate temperature ranges. If the determination in step S120 is "No", the process returns to step S110. If the determination in step S120 is "Yes", the process proceeds to step S130.

[0128] In step S130, the control device 60 acquires setting information related to the type of the working tool 300 and / or the type of the work performed by the working tool 300. The setting information can be generated based on information input by the user using the operation terminal 400 or other input devices. Alternatively, the setting information can also be generated based on the identification information of the working tool 300 sent from the working tool 300 to the working vehicle 200. The control device 60 can determine the type of the working tool 300 connected to the working vehicle 200 and / or the type of the work performed by the working tool 300 based on the setting information.

[0129] In the next step S140, the control device 60 sets the upper limit of the input power of the motor 70 corresponding to the type of the working tool 300 and / or the type of work determined based on the setting information. Fig. 7A , Figure 7B or Figure 7CThe data in the table shown in FIG. 1 is stored in the working vehicle 200 , and the upper limit value of the input power of the motor 70 corresponding to the type of the working tool 300 mounted on the working vehicle 200 and / or the type of the work is determined with reference to the data.

[0130] In the next step S150, the control device 60 determines whether to charge the battery. Whether to charge the battery depends on the remaining battery capacity and / or the battery temperature. For example, the control device 60 may also be configured to charge the battery in accordance with the following conditions: Figure 4 When the battery charging rate (SOC) monitored by the BMU of the battery pack 80 shown is lower than a threshold value (e.g., 80% or 90%), and the battery temperature monitored by the BMU is within a specified range (e.g., 0°C to 60°C), it is determined that the battery is charged. Conversely, the control device 60 may determine that the battery is not charged when the battery charging rate is above the threshold value or when the battery temperature is out of the specified range. When charging the battery, the process proceeds to step S160. When not charging the battery, the process proceeds to step S170.

[0131] In step S160, the control device 60 sets the upper limit of the output power of the FC module 10 to the sum of the upper limit of the input power of the motor 70 and a preset value α. α can be set to a value corresponding to the sum of the power required for charging the battery and the power required for driving other electrical components such as the DC-DC converters 81 and 82, for example.

[0132] In step S170, the control device 60 sets the upper limit of the output power of the FC module 10 to the sum of the upper limit of the input power of the motor 70 and a preset value β (<α). β can be set to, for example, the total value of the power required to drive electrical components other than the battery such as the DC-DC converters 81 and 82. β is smaller than α by the amount of power required to charge the battery.

[0133] After step S160 or S170, the control device 60 limits the power generation of the FC module 10 so as not to exceed the upper limit value of the output power of the set FC module 10. For example, even in a situation where the power generation should be increased, such as when the work tool 300 is traveling while performing a heavy load operation, the power generation is limited so that the output power of the FC module 10 does not exceed the upper limit value. The control device 60 sends a command to the control device (ECU) 42 of the FC module 10, and controls the operation of the air compressor 12, the fuel circulation pump 24, the coolant pump 31 and various valves, thereby being able to control the power generation of the FC stack 11. When operating in the output limit mode, the control device 60 may also cause the display device such as the operation terminal 400 or the meter 4, 6 to display information indicating that the output limit mode is in progress.

[0134] When the control device 60 operates in the output limiting mode, it sequentially obtains measurement data from each sensor and determines whether the condition for operating in the output limiting mode is satisfied, similarly to step S120. If the condition is not satisfied, the control device 60 returns from the output limiting mode to the normal mode. For example, if the temperature measured by each temperature sensor is within a specified range and the remaining amount of fuel in the fuel tank 50 is greater than a threshold value, the control device 60 may be configured to return from the output limiting mode to the normal mode. Afterwards, the control device 60 is executed again. Figure 8 Action shown.

[0135] In this way, the control device 60 in this embodiment shifts from the normal mode to the output restriction mode based on the measurement data of one or more sensors when the prescribed conditions are met. At this time, the control device 60 reduces the upper limit of the power supplied to the motor 70 to a value corresponding to the type of the working tool 300 connected to the working vehicle 200 and / or the type of operation. Thus, for example, when the remaining amount of fuel is small or when the temperature of the equipment such as the FC module 10 is not within the appropriate range, it is possible to shift to the output restriction mode to suppress the consumption of fuel and the heating of the equipment. In addition, the upper limit of the output power of the FC module 10 in the output restriction mode can be appropriately set according to the type of the working tool 300 and / or the type of operation. Thus, for example, according to the size of the load of the operation of the working tool 300, the consumption of fuel and the heating of the equipment can be effectively suppressed.

[0136] (4.3. Display example of display device)

[0137] When switching from the normal mode to the output limit mode, the control device 60 may cause the display device to display information indicating that the mode is in the output limit mode. An example of displaying such information will be described below.

[0138] Fig. 9 A diagram schematically showing an example of display on a display device. Fig. 9 The display devices shown are the main meter 4 and the FC meter 6. The main meter 4 and the FC meter 6 in this example are digital meters. However, digital meters are not necessarily required. The display of the main meter 4 includes, for example, information related to the speed of the work vehicle 200, the time, the fuel consumption, an indicator of the direction indicator, a parking brake light, a charging light reporting an abnormality of the charging system, an indicator of a water temperature gauge indicating the state of the radiator device (for example, the temperature measured by the temperature sensor S3), and information 19 indicating that the output limit mode is in progress.

[0139] exist Fig. 9In the example shown, the FC meter 6 is arranged on both sides of the main meter 4. However, the FC meter 6 may be arranged only on one side of the main meter 4, and the shape of each meter is not limited to the example shown in the figure but is arbitrary. The FC meter 6 displays information related to the operating state of the FC power generation system 180. For example, the FC meter 6 may also display forecast information estimated based on the remaining amount of fuel and the content of the operation. Fig. 9 In the example shown, the FC meter 6 on the right side displays the predicted information of the drivable distance, the drivable (operable) time, and the work area. However, it is not necessary to display all of this information. For example, the drivable distance and the drivable time may be displayed without displaying the information of the work area. The FC meter 6 on the right side also displays information on the type of work tool and the type of work.

[0140] Fig. 9 The display of the left FC meter 6 in the example shown includes information related to the battery SOC indicating the state of charge of the battery pack 80, the remaining amount (%) of the fuel in the fuel tank 50, the temperature (° C.) of the fuel tank, and the value (kPa) of the sensor S4 (pressure sensor) provided in the fuel tank 50. The display of the left FC meter 6 also includes indicators corresponding to the power generation state of the FC stack 11, the warning lamp 9 for warning of abnormality of the fuel tank 50, and the battery SOC and the remaining amount of fuel, respectively.

[0141] Fig.10 This is a diagram schematically showing another example of display on the display device. Fig.10 The display device shown as an example is the operation terminal 400. The screen of the operation terminal 400 can also display information that is the same as or similar to the information that can be displayed on the FC meter 6. Fig.10 The screen of the illustrated operation terminal 400 displays, in addition to information 19 indicating that the output limit mode is in effect, the type of work tool, the type of work, and forecast information, an input interface for setting the vehicle speed and tillage depth, and vehicle information.

[0142] Thus, by providing information indicating that the output limiting mode is in effect to, for example, a driver sitting in a driver's seat or a user using an operation terminal, it is possible to easily urge the driver or user to, for example, refuel or determine whether to stop the operation of a work tool. Furthermore, by providing information related to the operation state of the FC power generation system to the driver or user, it is possible to easily urge the driver or user to, for example, check the work vehicle or the FC power generation system.

[0143] The control device 60 may also cause the sound output device to output a sound indicating the switch to the output limit mode and / or a sound urging the fuel supply. For example, the control device 60 may also use a speaker to cause the speaker to output a sound notifying the switch to the output limit mode or a sound urging the fuel supply. Alternatively, the control device 60 may cause a buzzer to output a buzzer sound indicating the switch to the output limit mode.

[0144] 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.

[0145] 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.

[0146] [Project 1]

[0147] A working vehicle, wherein

[0148] have:

[0149] A fuel cell module having a fuel cell stack;

[0150] at least one fuel tank for containing fuel supplied to the fuel cell stack;

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

[0152] a power output shaft, driven by the motor and connected to a working tool; and

[0153] a control device for controlling the power supplied from the fuel cell module to the motor,

[0154] The control device can operate in a plurality of control modes.

[0155] The plurality of control modes include a normal mode and an output limiting mode, wherein an upper limit value of electric power supplied from the fuel cell module to the motor is smaller than that in the normal mode,

[0156] The control device changes an upper limit value of the electric power supplied to the motor in the output limiting mode according to a type of the working tool connected to the power output shaft and / or a type of work performed by the working tool.

[0157] [Project 2]

[0158] The work vehicle according to claim 1, wherein:

[0159] The work vehicle further includes a sensor for measuring the remaining amount of the fuel in the fuel tank.

[0160] When the measured remaining amount of the fuel is lower than a threshold value, the control device shifts from the normal mode to the output limiting mode and reduces the upper limit of the electric power supplied to the motor to a value corresponding to the type of the working tool and / or the type of the work.

[0161] [Item 3]

[0162] The working vehicle according to claim 1 or 2, wherein:

[0163] The work vehicle further includes a sensor for measuring the temperature of the fuel cell module.

[0164] When the measured temperature exceeds a threshold value, the control device shifts from the normal mode to the output limiting mode and reduces the upper limit of the electric power supplied to the motor to a value corresponding to the type of the working tool and / or the type of the work.

[0165] [Item 4]

[0166] The working vehicle according to claim 1 or 2, wherein:

[0167] The working vehicle also has:

[0168] an inverter device connected between the fuel cell module and the motor; and

[0169] a sensor for measuring a temperature of the inverter device or the motor,

[0170] When the measured temperature exceeds a threshold value, the control device shifts from the normal mode to the output limiting mode and reduces the upper limit of the electric power supplied to the motor to a value corresponding to the type of the working tool and / or the type of the work.

[0171] [Item 5]

[0172] The working vehicle according to claim 1 or 2, wherein:

[0173] The work vehicle further includes a storage device storing a table defining a correspondence relationship between the type of the work tool and / or the type of the work and an upper limit value of the electric power supplied to the motor.

[0174] The control device refers to the table to determine the upper limit value of the electric power corresponding to the type of the working tool connected to the power output shaft and / or the type of the work.

[0175] [Item 6]

[0176] The working vehicle according to claim 1 or 2, wherein:

[0177] The control device acquires identification information of the work tool from the work tool connected to the power output shaft, and determines the type of the work tool and / or the type of the work based on the identification information.

[0178] [Item 7]

[0179] The working vehicle according to claim 1 or 2, wherein:

[0180] The control device determines the type of the working tool connected to the power output shaft based on information related to the type of the working tool and / or the type of the work input by a user via an input device.

[0181] [Item 8]

[0182] The working vehicle according to claim 1 or 2, wherein:

[0183] The working vehicle further includes a battery connected to the fuel cell module and the motor.

[0184] In the output limiting mode, the control device

[0185] determining whether to charge the battery,

[0186] When charging is performed, the electric power output from the fuel cell module is increased compared to when charging is not performed.

[0187] [Item 9]

[0188] The work vehicle according to claim 8, wherein:

[0189] The control device determines whether to charge the battery based on at least one of a charging rate (SOC) of the battery and a temperature of the battery.

[0190] [Item 10]

[0191] The working vehicle according to claim 1 or 2, wherein:

[0192] The working vehicle is an agricultural machine.

[0193] [Item 11]

[0194] A control device for a working vehicle, the working vehicle having a power output shaft connected to a working tool, the power output shaft being driven by a motor connected to a fuel cell module, wherein:

[0195] The control device can operate in a plurality of control modes.

[0196] The plurality of control modes include a normal mode and an output limiting mode, wherein an upper limit value of electric power supplied from the fuel cell module to the motor is smaller than that in the normal mode,

[0197] The control device changes the upper limit value of the electric power in the output limiting mode according to the type of the working tool connected to the power output shaft and / or the type of work performed by the working tool.

[0198] [Item 12]

[0199] A control method for a working vehicle, wherein the working vehicle has a power output shaft connected to a working tool, the power output shaft is driven by a motor connected to a fuel cell module, wherein:

[0200] The control method includes actions in a plurality of control modes,

[0201] The plurality of control modes include a normal mode and an output limiting mode, wherein an upper limit value of electric power supplied from the fuel cell module to the motor is smaller than that in the normal mode,

[0202] The control method includes changing the upper limit value of the electric power in the output limiting mode according to the type of the working tool connected to the power output shaft and / or the type of work performed by the working tool.

[0203] Industrial Applicability

[0204] 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.

[0205] Description of reference numerals:

[0206] 1 user interface, 2 operation device, 3 main ECU, 4 main instrument, 5 FC system ECU, 6 FC instrument, 7 storage device, 8 sound output device, 10 fuel cell module, 11 FC stack, 40 boost circuit, 34 radiator device, 40 boost circuit, 42 ECU, 50 fuel tank, 51 tank case, 60 control device, 70 motor, 71 output shaft, 72 inverter device, 73 ECU, 74 power transmission system, 76 power take-off (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 power output shaft, driven by the motor and connected to a working tool; as well as a control device for controlling the power supplied from the fuel cell module to the motor, The control device can operate in a plurality of control modes. The plurality of control modes include a normal mode and an output limiting mode, wherein an upper limit value of electric power supplied from the fuel cell module to the motor is smaller than that in the normal mode, The control device changes an upper limit value of the electric power supplied to the motor in the output limiting mode according to a type of the working tool connected to the power output shaft and / or a type of work performed by the working tool.

2. The work vehicle according to claim 1, wherein: The work vehicle further includes a sensor for measuring the remaining amount of the fuel in the fuel tank. When the measured remaining amount of the fuel is lower than a threshold value, the control device shifts from the normal mode to the output limiting mode and reduces the upper limit of the electric power supplied to the motor to a value corresponding to the type of the working tool and / or the type of the work.

3. The working vehicle according to claim 1 or 2, wherein: The work vehicle further includes a sensor for measuring the temperature of the fuel cell module. When the measured temperature exceeds a threshold value, the control device shifts from the normal mode to the output limiting mode and reduces the upper limit of the electric power supplied to the motor to a value corresponding to the type of the working tool and / or the type of the work.

4. The working vehicle according to claim 1 or 2, wherein: The working vehicle also has: an inverter device connected between the fuel cell module and the motor; and a sensor for measuring a temperature of the inverter device or the motor, When the measured temperature exceeds a threshold value, the control device shifts from the normal mode to the output limiting mode and reduces the upper limit of the electric power supplied to the motor to a value corresponding to the type of the working tool and / or the type of the work.

5. The working vehicle according to claim 1 or 2, wherein: The work vehicle further includes a storage device storing a table defining a correspondence relationship between the type of the work tool and / or the type of the work and an upper limit value of the electric power supplied to the motor. The control device refers to the table to determine the upper limit value of the electric power corresponding to the type of the working tool connected to the power output shaft and / or the type of the work.

6. The working vehicle according to claim 1 or 2, wherein: The control device acquires identification information of the work tool from the work tool connected to the power output shaft, and determines the type of the work tool and / or the type of the work based on the identification information.

7. The working vehicle according to claim 1 or 2, wherein: The control device determines the type of the working tool connected to the power output shaft based on information related to the type of the working tool and / or the type of the work input by a user via an input device.

8. The working vehicle according to claim 1 or 2, wherein: The working vehicle further includes a battery connected to the fuel cell module and the motor. In the output limiting mode, the control device determining whether to charge the battery, When charging is performed, the electric power output from the fuel cell module is increased compared to when charging is not performed.

9. The work vehicle according to claim 8, wherein: The control device determines whether to charge the battery based on at least one of a charging rate (SOC) of the battery and a temperature of the battery.

10. The working vehicle according to claim 1 or 2, wherein: The working vehicle is an agricultural machine.

11. A control device for a working vehicle, the working vehicle having a power output shaft connected to a working tool, the power output shaft being driven by a motor connected to a fuel cell module, wherein: The control device can operate in a plurality of control modes. The plurality of control modes include a normal mode and an output limiting mode, wherein an upper limit value of electric power supplied from the fuel cell module to the motor is smaller than that in the normal mode, The control device changes the upper limit value of the electric power in the output limiting mode according to the type of the working tool connected to the power output shaft and / or the type of work performed by the working tool.

12. A control method for a work vehicle, the work vehicle having a power output shaft connected to a work tool, the power output shaft being driven by a motor connected to a fuel cell module, wherein: The control method includes actions in a plurality of control modes, The plurality of control modes include a normal mode and an output limiting mode, wherein an upper limit value of electric power supplied from the fuel cell module to the motor is smaller than that in the normal mode, The control method includes changing the upper limit value of the electric power in the output limiting mode according to the type of the working tool connected to the power output shaft and / or the type of work performed by the working tool.

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