Work vehicle

Abstract

To monitor the fuel supply status from a fuel tank to a fuel cell in a work vehicle.SOLUTION: A work vehicle is equipped with a fuel cell, a fuel tank that stores fuel to be supplied to the fuel cell, a detection device that detects the state of fuel released from the fuel tank, and a control device, and the control device calculates the amount of fuel released based on the state of the fuel detected by the detection device and the amount of fuel consumed in the fuel cell.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a work vehicle driven by a fuel cell.

Background Art

[0002] In recent years, in work vehicles such as tractors, from the perspective of global environmental protection, instead of an internal combustion engine using fossil fuels, a fuel cell that generates electricity using hydrogen is used, and a traveling device and a working device are operated by an electric motor driven by the generated electricity. For example, Patent Document 1 discloses a work vehicle equipped with a fuel cell and a hydrogen tank, which supplies hydrogen in the hydrogen tank to the fuel cell for power generation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a work vehicle equipped with a fuel cell, it is required that hydrogen gas released from a hydrogen tank be appropriately supplied to the fuel cell and consumed by the fuel cell. However, in the work vehicle of Patent Document 1, it is impossible to grasp whether the supply state of hydrogen gas is appropriate.

[0005] The present disclosure provides a work vehicle capable of grasping the supply state of fuel from a fuel tank to a fuel cell.

Means for Solving the Problems

[0006] The work vehicle of the present disclosure includes a fuel cell, a fuel tank that stores fuel to be supplied to the fuel cell, a detection device that detects the state of fuel released from the fuel tank, and a control device. The control device calculates a fuel discharge amount based on the state of the fuel detected by the detection device and a fuel consumption amount consumed in the fuel cell.

Advantages of the Invention

[0007] According to the present disclosure, in a work vehicle driven by a fuel cell, it is possible to grasp the supply state of fuel from a fuel tank to the fuel cell.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0009] <Outline of Embodiment of the Present Disclosure> Hereinafter, the outline of the embodiment of the present disclosure will be listed and described. (1) The work vehicle according to this embodiment includes a fuel cell, a fuel tank that stores fuel to be supplied to the fuel cell, a detection device that detects the state of the fuel discharged from the fuel tank, and a control device, and the control device calculates a fuel discharge amount based on the state of the fuel detected by the detection device and a fuel consumption amount consumed in the fuel cell.

[0010] According to the above configuration, the supply state of fuel from the fuel tank to the fuel cell can be grasped by using the fuel discharge amount released from the fuel tank and the fuel consumption amount consumed in the fuel cell.

[0011] (2) In the work vehicle of the above (1), the control device calculates the difference between the fuel discharge amount and the fuel consumption amount, and determines the presence or absence of an abnormality based on the difference. According to the above configuration, the difference between the fuel discharge amount and the fuel consumption amount can be used to grasp how much of the fuel released from the fuel tank is consumed in the fuel cell, and to determine the presence or absence of an abnormality such as fuel leakage in the supply path.

[0012] (3) The work vehicle of the above (2) is provided with a notification device that notifies the determination result of the presence or absence of the abnormality. According to this configuration, the user can easily recognize that there is an abnormality in the supply of fuel from the fuel tank to the fuel cell.

[0013] (4) The work vehicle of the above (1) or (2) is provided with a notification device that notifies the fuel discharge amount and the fuel consumption amount. According to this configuration, the degree to which the fuel released from the fuel tank is consumed in the fuel cell can be easily grasped based on the notified fuel discharge amount and fuel consumption amount.

[0014] (5) Any one of the work vehicles of the above (1) to (4) includes a plurality of the fuel tanks, a switching valve that is provided corresponding to each of the plurality of fuel tanks and switches between the discharge of fuel from the fuel tank and the stop of the discharge, the detection device includes a pressure sensor that detects the pressure of the fuel merged from the plurality of fuel tanks through the switching valve, the control device calculates the fuel discharge amount based on the pressure detected by the pressure sensor.

[0015] According to this configuration, if any of the plurality of on-off valves fails to open due to a malfunction and fuel is released only from some of the fuel tanks, the pressure sensor will detect only the pressure of the fuel released from some of the fuel tanks. In this case, the pressure drop will be greater than when the same amount of fuel is released from all the fuel tanks. Since the fuel release amount correlates with the detected value of the pressure and the volume of the fuel tank, when the fuel release amount is obtained based on the detected value of the pressure and the volume of all the fuel tanks, there will be a difference between the obtained fuel release amount and the actually released fuel release amount, that is, the fuel consumption amount consumed by the fuel cell. Therefore, it is possible to determine whether there is a malfunction in the on-off valve based on this difference.

[0016] (6) In the work vehicle of (5) described above, the control device calculates the difference between the fuel release amount and the fuel consumption amount, determines the presence or absence of an abnormality based on the difference, and closes all the on-off valves based on the determination of the presence of an abnormality. According to this configuration, when an abnormality due to a malfunction of the on-off valve is determined, by closing all the on-off valves, the supply of fuel from the fuel tank to the fuel cell is stopped, and it is possible to suppress the continuation of the state where fuel is not properly supplied.

[0017] (7) In the work vehicle of any one of (2), (3), and (6) described above, the control device calculates the difference between a first integrated value obtained by integrating the fuel release amount over a predetermined period and a second integrated value obtained by integrating the fuel consumption amount over the period. According to this configuration, by integrating the fuel release amount and the fuel consumption amount in sections over a predetermined period, the accumulation of errors can be suppressed, and the supply state from the fuel tank to the fuel cell can be accurately grasped.

[0018] (8) In the work vehicle of (7) described above, the control device repeatedly executes a determination process in which one cycle consists of the calculation of the first integrated value and the second integrated value, the determination, and the reset of the first integrated value and the second integrated value. According to the above configuration, the first and second integrated values are calculated by dividing them at a predetermined period, and each time the presence or absence of an abnormality is determined, the first and second integrated values are reset and the determination process is repeated, so that an accurate determination can be continuously made.

[0019] (9) In the work vehicle of (8) described above, the control device regards the determination of the presence of an abnormality made in one determination process as a provisional abnormality determination, and when the provisional abnormality determinations are continuous for a predetermined number of times, the last provisional abnormality determination is confirmed as a formal abnormality determination. According to the above configuration, it is possible to suppress the detection device from determining a temporary false detection or the like as an abnormality.

[0020] (10) In the work vehicle according to any one of (1) to (9) described above, a pipe that connects the fuel tank and the fuel cell and allows fuel to flow from the fuel tank to the fuel cell is provided. The detection device includes a pressure sensor that is connected to the pipe and detects the pressure of the fuel flowing through the pipe. The control device calculates the fuel discharge amount based on the pressure detected by the pressure sensor. According to this configuration, the fuel discharge amount can be obtained from the detection value of the pressure sensor provided in the pipe.

[0021] (11) In the work vehicle of (10) described above, a pressure reducing valve provided in the pipe is further provided. The pressure sensor is provided in the pipe between the pressure reducing valve and the fuel tank. According to this configuration, the pressure sensor can detect the pressure of the fuel before being reduced by the pressure reducing valve, which corresponds to the pressure in the fuel tank.

[0022] (12) In the work vehicle according to (10) or (11) described above, the detection device includes a temperature sensor that detects the temperature in the fuel tank or the temperature in the pipe. The control device calculates the fuel discharge amount based on the temperature detected by the temperature sensor. According to this configuration, since the temperature of the fuel is correlated with the fuel emission amount, the fuel emission amount can be obtained based on this temperature.

[0023] <Details of Embodiments of the Present Disclosure> Hereinafter, with reference to the drawings, details of embodiments of the present disclosure will be described. Note that at least some of the embodiments described below may be arbitrarily combined.

[0024] 〔Overall Structure of the Work Vehicle〕 FIG. 1 is a perspective view of the work vehicle. FIG. 2 is a right side view of the work vehicle with some exterior parts removed. As shown in FIGS. 1 and 2, the work vehicle 1 is a vehicle used for agricultural work, specifically a tractor. However, the work vehicle 1 is not limited to a tractor and may be a moving body such as an agricultural machine, a construction machine, and a utility vehicle.

[0025] The work vehicle 1 includes a vehicle body 11, a traveling device 12 that supports the vehicle body 11, a driver's seat 15, a cabin 16, and the like. The vehicle body 11 includes a chassis 41, a bonnet 34, a cover 111, a cabin 16, and a fender for the rear wheels 12B. Specifically, on the chassis 41 of the vehicle body 11, a bonnet 34 and a cover 111 are mounted in order from the front to the rear, and a cabin 16 is arranged behind the cover 111.

[0026] The work vehicle 1 further includes a tank unit 21 having a plurality of tanks (fuel tanks) 13 (see FIG. 2) for storing fuel, and a drive device 14 driven by the stored fuel. The fuel is liquid or gas. The fuel is, for example, hydrogen, methane, carbon monoxide (CO). The fuel of this embodiment is hydrogen, and the plurality of tanks 13 are hydrogen tanks that store hydrogen gas (simply referred to as "hydrogen" hereinafter). Therefore, the work vehicle 1 is a fuel cell vehicle (FCV: Fuel Cell Vehicle), and runs using the electric power generated by the chemical reaction of hydrogen and oxygen in the fuel cell 24 as an energy source. The fuel cell 24 may generate electric power using methane or carbon monoxide.

[0027] The drive device 14 includes a fuel cell 24, a battery unit 30, and an electric motor 31 (see FIG. 3; hereinafter also referred to as "motor 31"). The battery unit 30 incorporates at least one battery pack 30A (see FIG. 4) that stores the output power of the fuel cell 24. The work vehicle 1 has a hydrogen gas pipe 22. Hydrogen gas is supplied from a gas filling port 52 (see FIG. 4) connected to the end of the pipe 22 and filled into each tank 13. The hydrogen gas in the tank 13 is supplied to the fuel cell 24 through the pipe 22.

[0028] The cab 16 is a partitioned driver's cab having front pillars, rear pillars, and a roof. The front pillars are arranged on the left and right sides in front of the driver's seat 15, and the rear pillars are arranged on the left and right sides behind the driver's seat 15. Instead of the cab 16, the work vehicle 1 may have a canopy or a rollover protective structure (ROPS). The tank unit 21 is arranged above the driver's seat 15 and the cab 16 by a mounting frame 17 described later.

[0029] The traveling device 12 is composed of front wheels 12A and rear wheels 12B. Both of these are arranged symmetrically with respect to the vehicle body 11. One or both of the front wheels 12A and the rear wheels 12B rotate by the power of the motor 31. One or both of the wheels 12A, 12B (drive wheels) that rotate by the power of the motor 31 may be crawlers (endless tracks).

[0030] As shown in FIG. 2, in the portion of the chassis 41 corresponding to the front wheels 12A, a first radiator 48, a fuel cell 24, and a second radiator 49 are mounted in order from the front side to the rear side. The first radiator 48 and the fuel cell 24 are covered by the bonnet 34 shown in FIG. 1, and the second radiator 49 is covered by a cover 111.

[0031] As shown in FIG. 1, the upper surface of the cover 111 is higher than the uppermost end of the bonnet 34, but lower than the uppermost end of the steering wheel in the driver's seat 15. Further, the rear end portion of the bonnet 34 is at a position lower than the cover 111, and the upper surface of the bonnet 34 is formed in a tapered shape that gradually becomes lower from the rear end portion toward the front end portion. For this reason, the structure is such that it is difficult to obstruct the forward view from the operator sitting in the driver's seat 15.

[0032] 〔Internal Structure of the Work Vehicle〕 FIG. 3 is a perspective view showing an example of the internal structure of the work vehicle. As shown in FIG. 3, the chassis 41 constituting the vehicle body 11 is made of a steel frame having a long shape in the front-rear direction, and has a front frame 32 and a transmission case 33. The transmission case 33 is connected to the rear portion of the front frame 32, and the skeleton of the vehicle body 11 is formed from the transmission case 33 and the front frame 32.

[0033] A mounting frame 17 for arranging the tank unit 21 above the cabin 16 is connected to the chassis 41. The mounting frame 17 includes a substantially rectangular ceiling frame 17A whose front-rear direction is longer than the left-right direction, a plurality of pillars 17B that support the ceiling frame 17A from below, and a pair of left and right reinforcing frames 17C connected to the front end portion of the ceiling frame 17A.

[0034] The tank unit 21 is connected to the ceiling frame 17A in a horizontally placed state. As shown in FIG. 2, the ceiling frame 17A is at a position higher than the roof of the cabin 16. Therefore, the tank unit 21 is arranged above the roof of the cabin 16.

[0035] The reinforcing frame 17C is a reinforcing diagonal member that slopes downward from the front end of the ceiling frame 17A to the front frame 32. Therefore, the rigidity of the mounting frame 17 in the front-rear direction is enhanced as compared with the case where the ceiling frame 17A and the tank unit 21 are supported only by the pillar 17B.

[0036] A support frame 37 for supporting the battery unit 30 on the vehicle body 11 is connected to the chassis 41 of the work vehicle 1. Specifically, a motor 31 is mounted on the front frame 32 of the chassis 41, and the support frame 37 is attached to the portion of the front frame 32 corresponding to the motor 31. The support frame 37 is made of, for example, a metal frame member and is attached in a cantilever state so as to protrude to the right from the front frame 32.

[0037] The transmission case 33 located behind the motor 31 has a power transmission mechanism inside. The power transmission mechanism includes a transmission, a clutch, and a differential gear, and decelerates or accelerates the rotation of the output shaft of the motor 31 and transmits it to the traveling device 12. The power transmission mechanism inside the transmission case 33 includes a branch mechanism that outputs a part of the power of the motor 31 to the PTO shaft 334 (see FIG. 4). The PTO shaft 334 is an output shaft that protrudes rearward from the transmission case 33.

[0038] A connecting device 44 (see FIG. 2), which is constituted by, for example, a three-point link mechanism, for connecting a working device 335 (see FIG. 4; also referred to as an "implement") for performing a desired agricultural work to the rear of the vehicle body 11 is attached to the transmission case 33. The three-point link mechanism can be constituted by, for example, an upper arm 44A protruding rearward from the transmission case 33 and a pair of left and right lower arms 44B. The working device 335 is, for example, a tillage tractor and a baler.

[0039] The rotational motion of the PTO shaft 334 is transmitted to the input shaft of the working device 335 connected to the connecting device 44, for example, during the driving of the traveling device 12. Therefore, the work vehicle 1 can drive the working device 335 by the power of the motor 31 while traveling in a field or the like.

[0040] 〔Functional Configuration of Work Vehicle〕 FIG. 4 is a block diagram showing an example of the functional configuration of the work vehicle. As shown in FIG. 4, the functional system of the work vehicle 1 includes a fuel system FS, a power system PS, and a temperature control system TS.

[0041] The components of the fuel system FS include at least one tank 13, valves 75 to 78, and sensors 81, 82, etc. The components of the temperature control system TS include a plurality of radiators 48, 49, and an air conditioner 50, etc. The components of the power system PS include a fuel cell 24, a boost circuit 61, an inverter 62, a motor 31, a transmission case 33, DC / DC converters 64, 65, and a battery unit (hereinafter also referred to as the "first battery") 30, etc.

[0042] The work vehicle 1 of the present embodiment includes a plurality of tanks 13, for example, three tanks 13. Each tank 13 is connected to pipes 22A, 22B. The pipe 22A is a gas pipe connecting the gas filling port 52 and each tank 13. The pipe 22A guides the hydrogen gas introduced into the gas filling port 52 to each tank 13. The pipe 22A branches into a plurality of branches on the downstream side, and each branch portion 22A1 is connected to each tank 13. A check valve 75 is provided at each branch portion 22A1 of the pipe 22A. Each check valve 75 suppresses the backflow of hydrogen gas from each tank 13 to the gas filling port 52 side.

[0043] The pipe 22B is a gas pipe connecting the fuel cell 24 and the tank 13. The pipe 22B guides the hydrogen gas stored in each tank 13 to the fuel cell 24. The pipe 22B branches into a plurality of parts on the upstream side, and each branch portion 22B1 is connected to the tank 13 respectively. An on-off valve 76 is provided at each branch portion 22B1 of the pipe 22B. Each on-off valve 76 switches between the release of hydrogen in each tank 13 and the stop (cut-off) of the release.

[0044] A pressure reducing valve 77 and a main on-off valve 78 are provided at the confluence portion 22B2 of the pipe 22B. The pressure reducing valve 77 reduces the pressure of the hydrogen gas released from the tank 13. The pressure of the hydrogen gas in the tank 13 is, for example, 35 megapascals or more, while the pressure of the hydrogen gas after being reduced by the pressure reducing valve 77 is, for example, about 2 atmospheres. The main on-off valve 78 switches between the supply of the hydrogen gas reduced by the pressure reducing valve 77 to the fuel cell 24 and the stop (cut-off) of the supply.

[0045] A pressure sensor 81 is provided between the plurality of on-off valves 76 and the pressure reducing valve 77. The pressure sensor 81 is provided at the confluence portion 22B2 of the pipe 22B. The pressure sensor 81 detects the pressure of the hydrogen gas released from the plurality of tanks 13. The pressure detected by the pressure sensor 81 corresponds to the pressure of the hydrogen gas in the tank 13 from which the hydrogen gas is released through the on-off valve 76. Further, a temperature sensor 82 is provided in each tank 13. The temperature sensor 82 detects the temperature of the hydrogen gas in the tank 13. The pressure sensor 81 and the temperature sensor 82 constitute a detection device for detecting the state of hydrogen (fuel).

[0046] The hydrogen gas released from the tank 13 and flowing through the pipe 22B is supplied to the fuel cell 24. The fuel cell 24 is, for example, a battery module configured by arranging a plurality of single cells having a positive electrode and a negative electrode in a stacked state. The fuel cell 24 aggregates the electric power generated by each single cell and generates the electric power required for driving the electric motor 31.

[0047] The fuel cell 24 is connected to the second radiator 49 through the cooling flow path H2. The electrodes of the fuel cell 24 are adjusted to a predetermined temperature by the coolant circulated from the second radiator 49. Thereby, the fuel cell 24 can maintain high power generation efficiency.

[0048] The fuel cell 24 is electrically connected to the input side of the boost circuit 61, and the output side of the boost circuit 61 is electrically connected to the DC side of the inverter 62. The boost circuit 61 raises the voltage input from the fuel cell 24 and outputs it to the inverter 62 and the battery unit 30.

[0049] The inverter 62 is electrically connected to the motor 31. The inverter 62 converts the DC input from the boost circuit 61 into three-phase AC and outputs it to the motor 31. Therefore, the power generated by the fuel cell 24 is stepped up and converted into AC and transmitted to the motor 31.

[0050] The motor 31 has a rotor and a stator having a plurality of coils, and drives the output shaft at a predetermined torque and rotational speed. For example, only one motor 31 is mounted on the work vehicle 1, and the output shaft of the motor 31 is coupled to the transmission case 33. A plurality of motors 31 may be mounted. For example, when two types of motors 31 for the front wheels 12A and the rear wheels 12B are provided, the power of each motor 31 may be output to the front wheels 12A and the rear wheels 12B, respectively.

[0051] The power transmission mechanism of the transmission case 33 outputs all or part of the power of the motor 31 to the traveling device 12. Further, when operating the work device 335, the power transmission mechanism also outputs the power of the motor 31 to the PTO shaft 334.

[0052] The battery unit 30 is a power storage device that absorbs the load fluctuations of the fuel cell 24. Specifically, the battery unit 30 temporarily charges the power supplied from the boost circuit 61 and discharges it during high load to supply drive power to the motor 31 to the inverter 62. The battery unit 30 includes a battery pack 30A and a monitoring unit 30B. The battery pack 30A includes at least one cell. The cell is a charge-discharge type such as, for example, a lithium-ion battery cell. The output voltage of the battery unit 30 is, for example, 24V.

[0053] The monitoring unit 30B includes a processor that performs switching control of the operation (charging or discharging) of the battery pack 30A and measurement of the state of charge (e.g., SOC).

[0054] The work vehicle 1 has a plurality of electrical components that operate at a voltage lower than that of the motor 31. DC power stepped down by a step-down circuit is supplied to these electrical components. The plurality of electrical components include, for example, an auxiliary battery (hereinafter also referred to as "second battery") 63, radiators 48, 49, and an air conditioner 50. The step-down circuit is, for example, a plurality of DC / DC converters 64, 65 (hereinafter also referred to as "first converter 64" and "second converter 65") having different output voltages.

[0055] The first converter 64 steps down the DC voltage input from the boost circuit 61 to a first voltage (e.g., 12 volts) and supplies it to the auxiliary battery 63, the air conditioner 50, and the like. The second converter 65 steps down the DC voltage input from the boost circuit 61 to a second voltage (e.g., 24 volts) and supplies it to the radiators 48, 49. The inverter 62 and both converters 64, 65 are disposed in a portion corresponding to the driver's seat 15 on the chassis 41. Note that the second voltage of the second converter 65 may be supplied to the battery unit 30.

[0056] As described above, the first radiator 48 is disposed in front of the fuel cell 24, and the second radiator 49 is disposed behind the fuel cell 24 (see Figure 2). These radiators 48, 49 constitute a cooling system that cools electrical components such as the fuel cell 24, the boost circuit 61, the inverter 62, the motor 31, and the first and second converters 64, 65 with a coolant (refrigerant).

[0057] A cooling channel H1 through which a coolant is circulated by a pump 66 is connected to the first radiator 48, and the coolant is cooled by heat exchange with external air. The first radiator 48 has a first fan 35 for promoting heat exchange with the external air. The components to be cooled by the cooling channel H1 of the first radiator 48 are electrical components (heat-generating components) such as, for example, a boost circuit 61, an inverter 62, a motor 31, and first and second converters 64, 65.

[0058] A cooling channel H2 through which a coolant is circulated by a pump 67 is connected to the second radiator 49, and the coolant is cooled by heat exchange with external air. The second radiator 49 has a second fan 36 for promoting heat exchange with the external air. The components to be cooled by the cooling channel H2 of the second radiator 49 are electrical components such as, for example, a fuel cell 24.

[0059] The auxiliary battery 63 is a power storage device that supplies power to a display, communication devices, etc. mounted on the driver's seat 15. The auxiliary battery 63 is, for example, a charge-discharge type lead-acid battery. The output voltage of the auxiliary battery (second battery) 63 is, for example, 12V, which is lower than the output voltage (for example, 24V) of the battery unit (first battery) 30. The auxiliary battery 63 can also be used as an auxiliary power source that supplies power to a control device 70, which will be described later, when the fuel cell 24 is stopped.

[0060] As shown in FIG. 4, the work vehicle 1 further includes a control device 70. The control device 70 can be constituted by an ECU (Electronic Control Unit) that communicates with various electrical components by a communication protocol such as CAN (Controller Area Network). For example, the control device 70 includes an ECU that comprehensively controls the entire system from power generation by the fuel cell 24 to power output, a fuel cell module including the fuel cell 24 and the boost circuit 61, and an ECU related to individual control of a tank module including the tank 13 and valves 75 to 78. Therefore, the control device 70 performs opening / closing control of the valves 75 to 78 included in the tank module, flow rate control of an injector that injects hydrogen into the fuel cell 24, acquisition of detection values of the pressure sensor 81 and the temperature sensor 82, and the like.

[0061] The control device 70 executes supply monitoring control for monitoring the supply state of hydrogen gas from the tank 13 to the fuel cell 24. Specifically, the control device 70 determines whether or not there is an abnormality in the supply state of hydrogen gas. Hereinafter, the content of the supply monitoring control will be described.

[0062] 〔Supply Monitoring Control〕 FIG. 5 is a graph for explaining an abnormality determination method used for hydrogen supply monitoring control. For supply monitoring control, the control device 70 acquires the detection values of the pressure sensor 81 and the temperature sensor 82, and calculates the discharge amount of hydrogen gas discharged from the tank 13 based on these detection values. The pressure and temperature of the hydrogen gas in the tank 13 are correlated with the filling amount of the hydrogen gas. In particular, the pressure of the hydrogen gas in the tank 13 decreases due to a decrease in the filling amount of the hydrogen gas in the tank 13. In other words, the pressure of the hydrogen gas in the tank 13 decreases due to an increase in the discharge amount of the hydrogen gas. Therefore, the discharge amount (fuel discharge amount) of the hydrogen gas in the tank 13 can be obtained using the pressure and temperature in the tank 13.

[0063] Specifically, the control device 70 obtains the filling amount of the hydrogen gas in the tank 13 by using the state equation with the volume of the tank 13, the pressure of the hydrogen gas, the temperature of the hydrogen gas, the hydrogen gas constant, a correction coefficient (such as the hydrogen compression coefficient), etc., and obtains the hydrogen release amount from the decrease amount of the filling amount (the difference from the previously obtained filling amount). Further, the control device 70 integrates the hydrogen release amount of the tank 13 for a predetermined period T. For example, in FIG. 5, the hydrogen release amount repeatedly integrated with the period T as one cycle is shown by a dotted line graph. When the period T elapses, the control device 70 resets the integrated value (the second integrated value) of the hydrogen release amount and newly integrates the hydrogen release amount. The period T can be, for example, 30 to 60 seconds.

[0064] Similarly, the control device 70 integrates the hydrogen consumption amount (fuel consumption amount) consumed in the fuel cell 24 for a predetermined period T. In FIG. 5, the hydrogen consumption amount repeatedly integrated with the period T as one cycle is shown by a solid line graph. Specifically, the control device 70 integrates the flow rate of the hydrogen gas (the injection amount per unit time) injected from the injector into the fuel cell 24 to obtain the hydrogen consumption amount for a predetermined period T. When the period T elapses, the control device 70 resets the integrated hydrogen consumption amount and newly integrates the hydrogen consumption amount.

[0065] The control device 70 compares the integrated hydrogen release amount with the hydrogen consumption amount. Specifically, the control device 70 obtains the difference ΔC between the hydrogen release amount and the hydrogen consumption amount. When this difference ΔC exceeds a predetermined threshold value α, it means that the hydrogen gas released from the tank 13 is not properly consumed in the fuel cell 24. For example, there may be a possibility that the hydrogen gas is leaking in the supply path of the hydrogen gas from the tank 13 to the fuel cell 24. In addition to the leakage of the hydrogen gas, there may also be a problem with the on-off valve 76. Therefore, when the difference ΔC exceeds the predetermined threshold value α, the control device 70 determines that an abnormality has occurred.

[0066] Hereinafter, the determination of the abnormality due to the problem of the on-off valve 76 will be described. When the control device 70 generates electricity using the fuel cell 24, it opens the on-off valves 76 corresponding to all the tanks 13. Then, the pressure of the hydrogen gas in all the tanks 13 is detected by the pressure sensor 81, and the hydrogen release amount is calculated using the pressure and the volume of all the tanks 13. However, if any of the on-off valves 76 fails to open properly due to a malfunction or the like and hydrogen is released only from some of the tanks 13, the amount of pressure drop becomes larger than when hydrogen is released from all the tanks 13. Since the control device 70 calculates the hydrogen release amount assuming that hydrogen is being released from all the tanks 13, the calculated hydrogen release amount becomes larger than the actual hydrogen release amount and larger than the hydrogen consumption amount in the fuel cell 24. Therefore, when the difference ΔC between the calculated hydrogen release amount and the hydrogen consumption amount is significantly larger than the threshold value α, not only hydrogen gas leakage but also the possibility of a malfunction of the on-off valve 76 is considered. In the present embodiment, by using the detection value of the pressure sensor for the calculation of the hydrogen release amount, it is possible to determine an abnormality caused by a malfunction (poor opening and closing) of the on-off valve 76.

[0067] As shown in FIG. 4, the work vehicle 1 includes a notification device 71. The notification device 71 includes a display panel such as a liquid crystal panel that displays characters and images, an organic EL (Electro Luminescence) panel, a lamp such as an LED (Light Emitting Diode) that emits light, a speaker or a buzzer that emits sound or a sound effect, and the like. The notification device 71 is arranged, for example, at the driver's seat 15.

[0068] The notification device 71 is controlled by the control device 70. As described above, when the difference ΔC between the hydrogen release amount and the hydrogen consumption amount exceeds a predetermined threshold value α, the control device 70 determines that there is an abnormality, controls the notification device 71, and notifies the user to that effect. The notification device 71 can notify information indicating "abnormality". For example, information such as "hydrogen supply abnormality", "hydrogen leakage", "valve abnormality", etc. can be displayed in characters or emitted by voice. Also, when it is determined that there is an abnormality, a lamp can be lit or blinked. The notification device 71 can display the hydrogen release amount and the hydrogen consumption amount obtained by calculation in characters or emit them by voice. The user can grasp that there is an abnormality in the supply state of the hydrogen gas by the notification of the notification device 71. Also, based on the notification of the notification device 71, the user can take measures to eliminate the abnormality, for example, inspect the piping 22 and the on-off valve 76, replace parts, etc.

[0069] When the abnormality is confirmed, the control device 70 may close all the on-off valves 76. Thereby, it is possible to suppress the fuel cell 24 from being driven while the leakage of the hydrogen gas and the malfunction of the on-off valve 76 remain.

[0070] The control device 70 of the present embodiment is configured to notify an abnormality by the notification device 71 when it is determined that there is an abnormality continuously for a predetermined number of times. For example, at time t0 shown in FIG. 5, the difference ΔC0 does not exceed the threshold value α and is in a normal state, and at the next time t1, the difference ΔC1 exceeds the threshold value α. However, at that time t1, it is not confirmed as an abnormality, and a "temporary" abnormality determination is made. Also at the next time t2, since the difference ΔC2 exceeds the threshold value α, the control device 70 makes a "temporary" abnormality determination. Then, when the "temporary" abnormality determination is made continuously for a predetermined number of times, the control device 70 makes the last "temporary" abnormality determination a formal abnormality determination and confirms the abnormality.

[0071] In the example shown in FIG. 5, an abnormality is officially confirmed through two provisional abnormality determinations, and the notification device 71 issues a notification of the abnormality. In this way, by determining an abnormality on the condition that the abnormality determination continues for a predetermined number of times, it is possible to exclude the determination of an abnormality caused by a temporary defect, for example, a temporary misdetection of sensors 81 and 82, or a temporary malfunction of the on-off valve 76.

[0072] FIG. 6 is a flowchart showing an example of the procedure for abnormality determination by the control device. The above procedure for abnormality determination will be described with reference to the flowchart of FIG. 6. In step S1, the control device 70 resets a counter n indicating the consecutive number of "provisional" abnormality determinations (n = 0). Next, in step S2, the control device 70 resets the hydrogen consumption Ca and the hydrogen release amount Cb, respectively (Ca = Cb = 0).

[0073] Next, in step S3, the control device 70 integrates the hydrogen consumption Ca and the hydrogen release amount Cb, respectively. Then, in step S4, the control device 70 determines whether or not a predetermined period T has elapsed since the start of the integration. When the predetermined period T has elapsed, in step S5, the difference ΔC is calculated.

[0074] In step S6, the control device 70 determines whether or not the difference ΔC exceeds a predetermined threshold value α. If the determination in step S6 is negative (difference ΔC ≤ threshold value α), the control device 70 returns the process to step S1 and performs the above processes of steps S1 to S5 again.

[0075] If the determination in step S6 is affirmative (difference ΔC > threshold α), the control device 70 increments the value of the counter n by one in step S7. Then, in step S8, the control device 70 determines whether the value of the counter n has reached the number of times N required for abnormal determination (n = N). If the determination in step S8 is negative, the control device 70 returns the process to step S2 and performs the processes of steps S2 to S7 above again. If the determination in step S8 is affirmative, the control device 70 determines that there is an abnormality in step S9. Thereafter, in step S10, the control device 70 controls the notification device 71 to notify of the abnormality.

[0076] 〔Other Modifications〕 The embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the rights of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope equivalent to the configurations described in the claims.

[0077] For example, although the work vehicle 1 of the above embodiment includes a plurality of tanks 13, it may include one tank 13. A plurality of pressure sensors 81 may be provided corresponding to each of the plurality of tanks 13. In this case, it becomes possible to obtain the hydrogen release amount for each tank 13. The control device 70 may notify of the abnormality by the notification device 71 by a single abnormal determination. Further, the control device 70 of the work vehicle 1 of the above embodiment calculates the hydrogen release amount based on the hydrogen detection state detected by the detection devices 81 and 82 and the hydrogen consumption amount consumed in the fuel cell 24. However, instead of the hydrogen release amount, the release amount of methane (methane gas) or the release amount of carbon monoxide (CO gas) may be calculated, and instead of the hydrogen consumption amount, the consumption amount of methane (methane gas) or the consumption amount of carbon monoxide (CO gas) may be calculated. In this case, when obtaining the release amount or consumption amount of methane, "hydrogen" described in the above embodiment may be read as "methane", and when obtaining the consumption amount of carbon monoxide (CO gas), "hydrogen" described in the above embodiment may be read as "carbon monoxide".

Explanation of Reference Numerals

[0078] 1: Work vehicle 13: Tank (fuel tank) 22: Pipe 24: Fuel cell 70: Control device 71: Notification device 76: On-off valve 77: Pressure reducing valve 81: Pressure sensor (detection device) 82: Temperature sensor (detection device)

Claims

1. A fuel cell, a fuel tank for storing fuel to be supplied to the fuel cell, a detection device for detecting the state of the fuel discharged from the fuel tank, and a control device, wherein the control device calculates a fuel discharge amount based on the state of the fuel detected by the detection device and a fuel consumption amount consumed in the fuel cell, and is a work vehicle.

2. The control device calculates a difference between the fuel discharge amount and the fuel consumption amount, and determines the presence or absence of an abnormality based on the difference. The work vehicle according to claim 1.

3. The work vehicle according to claim 2, further comprising a notification device for notifying the determination result of the presence or absence of the abnormality.

4. The work vehicle according to claim 1, further comprising a notification device for notifying the fuel discharge amount and the fuel consumption amount.

5. A plurality of the fuel tanks, and on-off valves provided corresponding to each of the plurality of fuel tanks and switching between discharge of fuel from the fuel tank and stop of the discharge, wherein the detection device includes a pressure sensor for detecting the pressure of the fuel merged from the plurality of fuel tanks through the on-off valves, and the control device calculates the fuel discharge amount based on the pressure detected by the pressure sensor. The work vehicle according to any one of claims 1 to 4.

6. The control device calculates a difference between the fuel discharge amount and the fuel consumption amount, determines the presence or absence of an abnormality based on the difference, and closes all the on-off valves based on the determination of the presence of an abnormality. The work vehicle according to claim 5.

7. The control device calculates a difference between a first integrated value obtained by integrating the fuel discharge amount over a predetermined period and a second integrated value obtained by integrating the fuel consumption amount over the period. The work vehicle according to claim 2 or 3.

8. The control device repeatedly executes a determination process in which calculation of the first integrated value and the second integrated value, the determination, and reset of the first integrated value and the second integrated value are defined as one cycle. The work vehicle according to claim 7.

9. The control device regards the determination of the presence of an abnormality made in one determination process as a provisional abnormality determination, and when the provisional abnormality determinations are continuous for a predetermined number of times, determines the last provisional abnormality determination as a formal abnormality determination. The work vehicle according to claim 8.

10. a pipe connecting the fuel tank and the fuel cell and allowing fuel to flow from the fuel tank to the fuel cell, wherein the detection device includes a pressure sensor connected to the pipe and detecting the pressure of the fuel flowing through the pipe, The work vehicle according to any one of claims 1 to 4, wherein the control device calculates the fuel discharge amount based on the pressure detected by the pressure sensor.

11. further comprising a pressure reducing valve provided in the pipe, The work vehicle according to claim 10, wherein the pressure sensor is provided in the pipe between the pressure reducing valve and the fuel tank.

12. The detection device includes a temperature sensor that detects the temperature inside the fuel tank or the temperature inside the pipe, The work vehicle according to any one of claims 1 to 4, wherein the control device calculates the fuel discharge amount based on the temperature detected by the temperature sensor.

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