Work machine, system for work machine, and method for controlling work machine

Abstract

A work machine (100) has a fuel cell stack (22), a hydrogen tank (21), a hydrogen valve (24), a body (11), and a controller (30). The fuel cell stack (22) generates electricity by causing oxygen and hydrogen to react. The hydrogen tank (21) supplies hydrogen to the fuel cell stack (22). The hydrogen valve (24) opens and closes a hydrogen flow path from the hydrogen tank (21) to the fuel cell stack (22). The body (11) supports each of the fuel cell stack (22) and the hydrogen tank (21). The controller (30) controls the opening and closing of the hydrogen valve (24) on the basis of the inclination angle of the body (11).

Description

Work machine, work machine system, and control method for work machine

[0007]

[0001] The present disclosure relates to a work machine, a work machine system, and a control method for a work machine.

[0002] Conventionally, new energy that does not emit greenhouse gases such as carbon dioxide has been developed in work machines and the like. As such energy, for example, fuel cells have attracted attention. A fuel cell generates electrical energy by causing a chemical reaction between hydrogen and oxygen in a fuel cell stack. In a fuel cell, only water is discharged after power generation, and carbon dioxide is not discharged. A work machine equipped with such a fuel cell is described in, for example, International Publication No. 2022 / 137688 (Patent Document 1).

[0003] International Publication No. 2022 / 137688

[0004] Work machines such as hydraulic excavators may have a large inclination of the entire work machine compared to passenger vehicles. When a hydrogen system device such as a fuel cell through which hydrogen flows is excessively inclined, an abnormality may occur in the operation of the hydrogen system device. In this case, hydrogen may leak from the hydrogen system device.

[0005] An object of the present disclosure is to provide a work machine, a work machine system, and a control method for a work machine that can suppress hydrogen leakage.

[0006] Each of the work machine and the work machine system in the present disclosure includes a hydrogen power source, a hydrogen tank, a hydrogen valve, a vehicle body, and a controller. The hydrogen power source is a power source that uses hydrogen. The hydrogen tank supplies hydrogen to the hydrogen power source. The hydrogen valve opens and closes a flow path of hydrogen from the hydrogen tank to the hydrogen power source. The vehicle body supports each of the hydrogen power source and the hydrogen tank. The controller controls the opening and closing of the hydrogen valve based on the inclination angle of the vehicle body.

[0007] The method for controlling a work machine in this disclosure comprises a hydrogen power source, a hydrogen tank for supplying hydrogen to the hydrogen power source, a hydrogen valve for opening and closing the hydrogen flow path from the hydrogen tank to the hydrogen power source, and a vehicle body supporting the hydrogen power source and the hydrogen tank, and includes the following steps: The inclination angle of the vehicle body is detected. If the inclination angle is greater than or equal to a first predetermined angle set in advance, the hydrogen valve is closed.

[0008] According to this disclosure, it is possible to realize a work machine, a work machine system, and a control method for a work machine that can suppress hydrogen leakage.

[0009] This is a side view showing the configuration of a work machine having a fuel cell in one embodiment of the present disclosure. This is a side view showing the arrangement of the fuel cell stack, hydrogen tank, and battery in the work machine shown in Figure 1. This is a rear view showing the arrangement of the fuel cell stack, hydrogen tank, and battery in the work machine shown in Figure 1. This is a partial cross-sectional view showing the connection between the hydrogen tank and the hydrogen valve in the work machine shown in Figure 1. This is a functional block diagram showing the work machine system in one embodiment of the present disclosure. This is a flow diagram showing the control method of the work machine in one embodiment of the present disclosure. This is a diagram showing the power supply flow to the inverter when the hydrogen valve is closed. This is a flow diagram showing the control method of the fuel cell stack and battery in one embodiment of the present disclosure.

[0010] The embodiments of this disclosure will be described below with reference to the drawings. In the specification and drawings, the same components or corresponding components are denoted by the same reference numerals, and redundant descriptions are avoided. In addition, for the sake of clarity, some components may be omitted or simplified in the drawings.

[0011] In the following explanation, "up," "down," "forward," "backward," "left," and "right" refer to directions relative to the operator seated in the driver's seat 14S inside the driver's cab 14 shown in Figure 1.

[0012] Therefore, in the following, the front-rear direction X is the direction in which the boom 16 extends between its base and tip when viewed from above. The left-right direction Y is the direction perpendicular to the front-rear direction X when viewed from above. The up-down direction Z is the direction perpendicular to the plane containing the mutually perpendicular front-rear direction X and left-right direction Y.

[0013] The direction from the base to the tip of the boom 16 is forward, and the direction from the tip to the base of the boom 16 is rear. In a viewpoint looking from rear to front, the right and left sides are to the right and left, respectively. In the vertical direction, the side with the ground is down, and the side with the sky is up. A top view means a viewpoint looking at the work machine 100 from above and below. A side view means a viewpoint looking at the slewing body 13 from the left or right. A rear view means a viewpoint looking at the slewing body 13 from rear to front.

[0014] <Configuration of the Working Machine> Hereinafter, the working machine of this disclosure will be described using Figures 1 to 4, with a fuel cell-equipped excavator as an example.

[0015] The work machines described herein are not limited to excavators, but may also include bulldozers, wheel loaders, motor graders, dump trucks, forklifts, etc., that have fuel cells. Furthermore, the work machines to which this disclosure applies are not limited to those having fuel cells, but may have a hydrogen power source, which is a power source that utilizes hydrogen. The hydrogen power source may be, for example, a hydrogen co-firing engine that burns hydrogen mixed with fossil fuels, or a hydrogen-only engine that burns only hydrogen without using fossil fuels.

[0016] Figure 1 is a schematic side view showing the configuration of a work machine in one embodiment of the present disclosure. As shown in Figure 1, the work machine 100 of this embodiment is, for example, an excavator having a fuel cell. The fuel cell generates electricity (electrical energy) by chemically reacting hydrogen and oxygen.

[0017] The generated electrical energy drives the hydraulic pump 35 (Figure 5). The hydraulic fluid discharged from the hydraulic pump 35 operates each hydraulic actuator (slewing motor, travel motor, and each hydraulic cylinder). If each hydraulic actuator is an electric motor, the generated electrical energy is supplied to the electric motor.

[0018] The work machine 100 has a fuel cell stack 22 as an example of the fuel cell of this disclosure. The fuel cell stack 22 is made by stacking a plurality of fuel cell cells connected in series. The work machine 100 has, for example, one fuel cell stack 22, but the number of fuel cell stacks 22 mounted on the work machine 100 is not limited to one, and there may be two or more.

[0019] The work machine 100 has hydrogen tanks 21 for supplying hydrogen to the fuel cell stack 22. The work machine 100 has, for example, two hydrogen tanks 21, but the number of hydrogen tanks 21 mounted on the work machine 100 is not limited to two; it may be one, or it may be three or more.

[0020] The work machine 100 has a battery 27. The battery 27 is, for example, made up of multiple lithium-ion battery cells stacked together. The battery 27 is charged by the power output from the fuel cell stack 22. The battery 27 may also be charged by an external power source. The hydraulic pump 35 is driven by the power output from the battery 27. Therefore, each of the hydraulic actuators (slewing motor, travel motor, each hydraulic cylinder) is driven by power supplied from at least one of the fuel cell stack 22 or the battery 27.

[0021] The work machine 100 has a main body 11 and a hydraulically operated work machine 12. The main body 11 is an example of a vehicle body according to this disclosure. The main body 11 has a slewing body 13 and a traveling body 15.

[0022] The vehicle 15 has a pair of left and right tracks 15Cr and a drive motor 15M. The work machine 100 can move by the rotation of the tracks 15Cr. The drive motor 15M is provided as a drive source for the vehicle 15. The drive motor 15M may be a hydraulic motor or an electric motor.

[0023] The slewing body 13 is positioned on and supported by the traveling body 15. The slewing body 13 is capable of rotating relative to the traveling body 15 about a pivot axis RX by a slewing motor (not shown). The pivot axis RX is a hypothetical straight line that serves as the pivot center of the slewing body 13. The slewing motor may be a hydraulic motor or an electric motor.

[0024] The slewing body 13 has a cab 14. Inside the cab 14 is a driver's seat 14S where the operator sits. The operator can sit in the driver's seat 14S and operate the work implement 12, rotate the slewing body 13 relative to the traveling body 15, and operate the traveling body 15 to move the work machine 100.

[0025] The work implement 12 is supported by a slewing body 13. The work implement 12 has a boom 16, an arm 17, and a bucket 18. The work implement 12 further has a boom cylinder 19a, an arm cylinder 19b, and a bucket cylinder 19c. Each cylinder 19a, 19b, and 19c may be a hydraulic cylinder or be driven by an electric motor.

[0026] The boom 16 is rotatably connected to the main body 11. Specifically, the base end of the boom 16 is rotatably connected to the slewing body 13 with the boom foot pin BF as the pivot point. The base end of the boom 16 is positioned in the left-right direction of the operator's cab 14. The arm 17 is rotatably connected to the boom 16. Specifically, the base end of the arm 17 is rotatably connected to the tip of the boom 16 with the boom top pin BT as the pivot point. The bucket 18 is rotatably connected to the arm 17. Specifically, the base end of the bucket 18 is rotatably connected to the tip of the arm 17 with the arm top pin AT as the pivot point.

[0027] The rotating body 13 has an exterior panel OP that surrounds the machine room. Inside the machine room of the rotating body 13 are a hydrogen tank 21, a fuel cell stack 22, a battery 27, a cooling unit CU (Figure 3), etc. The hydrogen tank 21, fuel cell stack 22, battery 27, cooling unit CU, etc. are covered by the exterior panel OP.

[0028] In the above description, the driver's seat 14S is located inside the driver's cab 14, but the driver's cab 14 may be absent and the driver's seat 14S may be exposed to the outside. Furthermore, the work machine 100 may not have a driver's cab 14 and may operate automatically and unmanned. Also, the work machine 100 may not have a driver's cab 14 and may be operated remotely by a remote controller.

[0029] Figures 2 and 3 are side and rear views, respectively, showing the arrangement of the fuel cell stack, hydrogen tank, and battery in the work machine shown in Figure 1. As shown in Figure 2, the work machine 100 further includes a fuel cell unit support mechanism FS, a hydrogen tank support mechanism TF, and a tilt sensor 1.

[0030] The fuel cell unit support mechanism FS supports the hydrogen tank 21, the fuel cell stack 22, and the battery 27, respectively. The fuel cell unit support mechanism FS includes a base plate BP, a lower plate UP, an upper plate TP, a column member CM, and damping mechanisms DM1 and DM2. The base plate BP is fixed to the slewing frame 20 by bolting, welding, etc. The lower plate UP is connected to the base plate BP via the damping mechanism DM1, etc. The damping mechanism DM1 supports the lower plate UP relative to the base plate BP.

[0031] The base plate BP and the column member CM are fixed to each other by bolting, welding, etc. This restrains the base plate BP and the column member CM so that they cannot move relative to each other.

[0032] The column member CM extends in the vertical direction Z. The upper plate TP is connected to the column member CM via a damping mechanism DM2 or the like. The damping mechanism DM2 supports the upper plate TP relative to the column member CM. The upper plate TP, lower plate UP, and base plate BP are not limited to plates, but may also be frames.

[0033] The damping mechanisms DM1 and DM2 have the function of damping vibrations. The damping mechanisms DM1 and DM2 may be, for example, liquid-filled mounts or rubber. Liquid-filled mounts as damping mechanisms DM1 and DM2 are configured to obtain a large damping force due to the pressure loss when the sealed viscous liquid is constricted as it passes through a minute gap. The viscous liquid used in liquid-filled mounts may be, for example, silicone oil.

[0034] The tilt sensor 1 is attached to the main body 11. Specifically, the tilt sensor 1 is attached to the lower plate UP. The tilt sensor 1 detects the tilt angle of the main body 11. The tilt angle is, for example, the tilt angle of the main body 11 with respect to a horizontal plane. The tilt sensor 1 is, for example, an inertial measurement unit (IMU). The tilt sensor 1 detects, for example, the direction of gravity and detects a plane perpendicular to the direction of gravity as the horizontal plane.

[0035] The work machine 100 has, for example, one tilt sensor 1, but the number of tilt sensors 1 mounted on the work machine 100 is not limited to one, and may be two or more. By having multiple tilt sensors 1 on the work machine 100, redundancy can be increased. This improves the reliability of the tilt sensor 1.

[0036] Each of the fuel cell stacks 22 and batteries 27 is supported by the main body 11 (Figure 1) of the work machine 100. Specifically, each of the fuel cell stacks 22 and batteries 27 is attached to the slewing frame 20 via a lower plate UP, a damping mechanism DM1, and a base plate BP. Each of the fuel cell stacks 22, batteries 27, and tilt sensors 1 is positioned on the lower plate UP. The fuel cell stacks 22 and batteries 27 are arranged side by side, for example, in the front-to-back direction X, and extend in the left-to-right direction Y (Figure 3) so as to be substantially parallel to each other.

[0037] Each of the fuel cell stack 22, battery 27, and tilt sensor 1 is fixed to the lower plate UP by means of bolting, welding, etc. This restrains each of the fuel cell stack 22, battery 27, and tilt sensor 1 from moving relative to the lower plate UP. Therefore, the fuel cell stack 22, battery 27, tilt sensor 1, and lower plate UP are all included in the same vibration system, exhibiting the same vibration pattern relative to the slewing frame 20. However, each of the fuel cell stack 22, battery 27, tilt sensor 1, and lower plate UP, and the slewing frame 20, are included in different vibration systems.

[0038] The hydrogen tank support mechanism TF is positioned on the upper plate TP. The hydrogen tank support mechanism TF and the upper plate TP are fixed together, for example, by bolting or welding. This restrains the hydrogen tank support mechanism TF so that it cannot move relative to the upper plate TP.

[0039] Each of the two hydrogen tanks 21 is positioned above the fuel cell stack 22 and the battery 27. Each of the two hydrogen tanks 21 is supported by the main body 11 of the work machine 100 (Figure 1). Specifically, each of the two hydrogen tanks 21 is attached to the slewing frame 20 via a hydrogen tank support mechanism TF, an upper plate TP, a damping mechanism DM2, a column member CM, and a base plate BP.

[0040] Each of the two hydrogen tanks 21 is fixed to the hydrogen tank support mechanism TF by means of a belt, for example. This restrains each of the two hydrogen tanks 21 so that it cannot move relative to the hydrogen tank support mechanism TF. For this reason, the hydrogen tanks 21, the hydrogen tank support mechanism TF, and the upper plate TP are included in the same vibration system, which has the same vibration pattern relative to the slewing frame 20. The hydrogen tanks 21, the hydrogen tank support mechanism TF, and the upper plate TP are each included in different vibration systems than the slewing frame 20.

[0041] The fuel cell stack 22 and the two hydrogen tanks 21 are connected to the swivel frame 20 via different damping mechanisms. This allows the two hydrogen tanks 21 and the fuel cell stack 22 to move relative to each other due to vibrations, etc. For this reason, the hydrogen tanks 21 and the fuel cell stack 22 are contained within different vibration systems.

[0042] The two hydrogen tanks 21 are arranged side by side, for example, in the front-to-back direction X. For example, each of the two hydrogen tanks 21 is positioned such that its longitudinal direction aligns with the left-to-right direction Y of the work machine 100.

[0043] A pressure reducer 23 is attached to the hydrogen tank support mechanism TF. The pressure reducer 23 has the function of reducing the pressure of the high-pressure hydrogen gas supplied from the hydrogen tank 21 to a level that can be used by the fuel cell stack 22, which is a power generation device, and has a pressure reducing valve. The pressure reducer 23 is positioned, for example, in front of the arrangement area AR of the two hydrogen tanks 21. The position of the pressure reducer 23 is not limited to the front of the arrangement area AR, but may be behind or to the side of the arrangement area AR.

[0044] The hydrogen tank 21 and the pressure reducer 23 are connected by a tank hose TH (Fig. 4). Through this tank hose TH, the high-pressure hydrogen gas in the hydrogen tank 21 is supplied to the pressure reducer 23. A hydrogen valve 24 is arranged between the hydrogen tank 21 and the tank hose TH. The hydrogen valve 24 opens and closes the flow path of the high-pressure hydrogen gas from the hydrogen tank 21 to the fuel cell stack 22. Specifically, by the opening and closing operation of the hydrogen valve 24, the supply of the high-pressure hydrogen gas from the hydrogen tank 21 to the pressure reducer 23 is controlled to start and stop. The hydrogen valve 24 is, for example, of the normally closed type and always maintains a closed state when no external signal is applied. Generally, a gate valve can be used for the hydrogen valve 24.

[0045] The pressure reducer 23 and the fuel cell stack 22 are connected by a stack hose SH. Through this stack hose SH, the hydrogen gas decompressed by the pressure reducer 23 is supplied to the fuel cell stack 22.

[0046] The connection part P1 between the fuel cell stack 22 and the stack hose SH, the connection part P2 between the hydrogen valve 24 and the tank hose TH, the connection part P3 between the stack hose SH and the pressure reducer 23, and the connection part P4 (not shown) between the tank hose TH and the pressure reducer 23 are locations where hydrogen gas is likely to leak. These connection parts P1, P2, P3, and P4 are arranged on the same side in the left-right direction Y. For example, the connection part P1 is located at the left end of the fuel cell stack 22, the connection part P2 is located at the left end of the hydrogen tank 21, and the connection parts P3 and P4 are located at the left end of the pressure reducer 23. It should be noted that the connection part P1 may be located at the right end of the fuel cell stack 22, the connection part P2 may be located at the right end of the hydrogen tank 21, and the connection parts P3 and P4 may be located at the right end of the pressure reducer 23.

[0047] As shown in Fig. 3, the working machine 100 has a cooling unit CU. The cooling unit CU has a radiator 25 and an electric fan 26.

[0048] The radiator 25 is a device for dissipating heat of a cooling medium (coolant, such as water) that cools the fuel cell stack 22. The radiator 25 is, for example, a heat exchanger. The radiator 25 is disposed, for example, on the side of the fuel cell stack 22, for example, on the left side of the fuel cell stack 22. Note that the radiator 25 may be disposed, for example, on the right side of the fuel cell stack 22, or may be disposed on the front side or the rear side of the fuel cell stack 22.

[0049] The electric fan 26 functions to release the heat radiated from the radiator 25 by sending air to the radiator 25. The electric fan 26 is disposed, for example, between the radiator 25 and the fuel cell stack 22.

[0050] Each hydrogen valve 24 of the two hydrogen tanks 21 is disposed on the same side in the longitudinal direction of the hydrogen tank 21. Each hydrogen valve 24 of the two hydrogen tanks 21 is disposed, for example, on the left side in the longitudinal direction of the hydrogen tank 21. Each hydrogen valve 24 of the two hydrogen tanks 21 is disposed at an end portion closer to the cooling unit CU among both end portions in the longitudinal direction of the hydrogen tank 21.

[0051] FIG. 4 is a partial cross-sectional view showing a connection portion between the hydrogen tank and the hydrogen valve in the working machine shown in FIG. 1. As shown in FIG. 4, the hydrogen tank 21 has an internal space 91 and an opening 92. The internal space 91 stores hydrogen. The opening 92 connects the internal space 91 and the outside of the hydrogen tank 21. The opening 92 opens in the longitudinal direction of the hydrogen tank 21. The hydrogen valve 24 is attached to the opening 92. Therefore, the internal flow path of the hydrogen valve 24 communicates with the internal space 91. <00001​​​​Figure 5 is a functional block diagram showing a work machine system in one embodiment of the present disclosure. In Figure 5, the flow of power supply is indicated by solid arrows, the flow of electrical signals is indicated by dashed arrows, mechanical connections are indicated by double lines, and the flow of hydrogen gas supply and hydraulic oil supply is indicated by dashed-dotted arrows. As shown in Figure 5, the work machine 100 further includes an inverter 28, an electric motor 34, and a notification unit 36.

[0054] The inverter 28 is connected to the fuel cell stack 22 and the battery 27 by electrical wiring. The fuel cell stack 22 and the battery 27 each supply power to the electric motor 34 through the inverter 28. The inverter 28 converts the DC power, which is the output of the fuel cell stack 22 and the battery 27, into AC power with controlled frequency and other properties. The inverter 28 supplies AC power to the electric motor 34 through the electrical wiring.

[0055] The electric motor 34 and the hydraulic pump 35 are mechanically connected. The driving force of the electric motor 34 is transmitted to the hydraulic pump 35, which drives the hydraulic pump 35. By driving, the hydraulic pump 35 operates the various hydraulic actuators, such as the travel motor 15M. As a result, the vehicle 15 is driven by power supplied from at least one of the fuel cell stack 22 or the battery 27.

[0056] The fuel cell stack 22 receives hydrogen from the hydrogen tank 21 through the hydrogen valve 24. The fuel cell stack 22 has, for example, a pump that supplies hydrogen to the fuel cell cells. Therefore, hydrogen flows into the fuel cell stack 22 due to the pressure difference between the internal space 91 of the hydrogen tank 21 and the outside of the hydrogen tank 21, and the force applied from the fuel cell stack 22. The fuel cell stack 22 controls the flow rate of hydrogen that flows from the hydrogen tank 21 into the fuel cell stack 22 based on a signal from the controller 30.

[0057] The notification unit 36 ​​may be, for example, a display device or a notification speaker. The notification unit 36 ​​is located, for example, inside the driver's cab 14. The battery 27 outputs information regarding the remaining charge of the battery 27 to the controller 30.

[0058] The controller 30 includes a tilt acquisition unit 30a, a calculation unit 30b, a valve control unit 30c, an output control unit 30d, a charge level acquisition unit 30e, a notification control unit 30f, and a memory 30g.

[0059] Figure 6 is a flowchart showing a control method for a work machine in one embodiment of the present disclosure. The control method for the work machine in this embodiment is started, for example, by a start operation by an operator. The start operation by the operator is, for example, an operation to turn the work machine 100 from the OFF state to the ON state by inserting a key into the key switch of the work machine 100. If the hydrogen valve 24 is of the normally closed type, for example, after the start operation by the operator, an open signal is output from the valve control unit 30c to the hydrogen valve 24, causing the hydrogen valve 24 to open. This starts the supply of hydrogen gas from the hydrogen tank 21 to the fuel cell stack 22.

[0060] As shown in Figures 5 and 6, in the control method for the work machine in this embodiment, after the start operation described above, the tilt sensor 1 detects the tilt angle of the main body 11 (step S1). The tilt sensor 1 outputs information regarding the detected tilt angle of the main body 11 to the controller 30. The tilt acquisition unit 30a acquires the information regarding the tilt angle of the main body 11 output from the tilt sensor 1.

[0061] The calculation unit 30b obtains information regarding the tilt angle of the main body 11 from the tilt acquisition unit 30a and obtains a first predetermined angle and a second predetermined angle that are pre-stored in the memory 30g. The first predetermined angle and the second predetermined angle are each the tilt angle of the main body 11 and are pre-set angles. The second predetermined angle is smaller than the first predetermined angle. For example, the first predetermined angle is 35° and the second predetermined angle is 25°.

[0062] The calculation unit 30b determines whether the tilt angle of the main body 11 detected by the tilt sensor 1 is greater than or equal to a second predetermined angle (step S2). If it is determined that the tilt angle of the main body 11 is not greater than or equal to the second predetermined angle (NO in step S2), the controller 30 repeats the execution of step S1. On the other hand, if it is determined that the tilt angle of the main body 11 is greater than or equal to the second predetermined angle (YES in step S2), the calculation unit 30b determines whether the tilt angle of the main body 11 detected by the tilt sensor 1 is greater than or equal to a first predetermined angle (step S3).

[0063] If it is determined that the tilt angle of the main unit 11 is not greater than or equal to a first predetermined angle (NO in step S3), the calculation unit 30b outputs a signal indicating the determination result to the notification control unit 30f. Based on the determination result that the tilt angle of the main unit 11 is greater than or equal to a second predetermined angle but not greater than or equal to a first predetermined angle, the notification control unit 30f outputs warning information to the notification unit 36. When the notification unit 36 ​​receives the warning information, it issues a warning, for example, urging the operator not to increase the tilt angle of the main unit 11.

[0064] If it is determined that the tilt angle of the main body 11 is greater than or equal to a first predetermined angle (YES in step S3), the calculation unit 30b outputs a signal indicating the determination result to the valve control unit 30c, the output control unit 30d, and the notification control unit 30f, respectively.

[0065] The valve control unit 30c controls the opening and closing of the hydrogen valve 24 based on the tilt angle detected by the tilt sensor 1. Specifically, the valve control unit 30c controls the hydrogen valve 24 to close based on the determination that the tilt angle of the main body 11 is greater than or equal to a first predetermined angle (step S5). If the hydrogen valve 24 is of the normally closed type, the open signal from the valve control unit 30c is stopped. This stops the supply of hydrogen gas from the hydrogen tank 21 to the fuel cell stack 22.

[0066] Figure 5 shows the power supply flow to the inverter 28 when the hydrogen valve 24 is open. Figure 7 shows the power supply flow to the inverter 28 when the hydrogen valve 24 is closed. In Figure 7, the dashed line indicates that power supply and hydrogen gas supply are stopped.

[0067] As shown in Figure 5, with the hydrogen valve 24 open, both the fuel cell stack 22 and the battery 27 can supply power to the inverter 28. Therefore, with the hydrogen valve 24 open, the vehicle 15 runs on power supplied from at least one of the fuel cell stack 22 and the battery 27. Also, with the hydrogen valve 24 open, the fuel cell stack 22 can supply power to the battery 27. This allows the battery 27 to be charged.

[0068] As shown in Figure 7, when the hydrogen valve 24 is closed, the fuel cell stack 22 does not supply power to either the inverter 28 or the battery 27. Therefore, after step S5, the vehicle 15 runs solely on power supplied by the battery 27.

[0069] As shown in Figure 6, when the hydrogen valve 24 is closed (Figure 7), the output control unit 30d controls the fuel cell stack 22 to stop the operation of the fuel cell stack 22 to supply hydrogen from the hydrogen tank 21 to the fuel cell stack 22 (step S6). Specifically, the output control unit 30d outputs a stop signal to the fuel cell stack 22 based on the determination result that the tilt angle of the main body 11 is greater than or equal to a first predetermined angle. Upon receiving the stop signal, the fuel cell stack 22 stops the operation of supplying hydrogen from the hydrogen tank 21 to the fuel cell stack 22.

[0070] When the hydrogen valve 24 is closed (Figure 7), the output control unit 30d adjusts the amount of power output from the battery 27 (step S7). Specifically, the calculation unit 30b obtains an upper limit power value that has been pre-stored in the memory 30g. The upper limit power value is a preset power value that represents the amount of power output by the battery 27.

[0071] The output control unit 30d controls the battery 27 so that the amount of power output from the battery 27 is less than or equal to the upper limit current value, based on the determination result that the tilt angle of the main body 11 is greater than or equal to a first predetermined angle. Furthermore, when the hydrogen valve 24 is closed, the output control unit 30d controls the battery 27 so that the amount of power output from the battery 27 is greater than or equal to the amount of power required to drive the driving motor 15M.

[0072] When the hydrogen valve 24 is closed (Figure 7), the notification control unit 30f controls the notification unit to notify the amount of time the vehicle 15 can operate using the power supplied from the battery 27 (step S8). Specifically, the charge level acquisition unit 30e acquires information regarding the remaining charge of the battery 27 from the battery 27. The calculation unit 30b acquires information regarding the remaining charge of the battery 27 from the charge level acquisition unit 30e and calculates the amount of time the vehicle 15 can operate based on the information regarding the remaining charge of the battery 27. The calculation unit 30b outputs information regarding the amount of time the vehicle 15 can operate to the notification control unit 30f.

[0073] The notification control unit 30f outputs notification information to the notification unit 36 ​​based on the determination result that the tilt angle of the main body 11 is greater than or equal to a first predetermined angle. The notification information includes information about the time that the mobile body 15 can travel, calculated by the calculation unit 30b. When the notification unit 36 ​​receives the notification information, it notifies the time that the mobile body 15 can travel. The notification unit 36 ​​may also issue a warning when it receives the notification information. Specifically, when the notification unit 36 ​​receives the notification information, it may issue a warning prompting the operator to immediately reduce the tilt angle of the main body 11.

[0074] The control method for the work machine 100 in this embodiment is then executed. Note that each of steps S6 to S8 may occur after step S5 and before step S6, or simultaneously with step S6. After step S5, the hydrogen valve 24 remains closed until, for example, the operator performs the start operation again.

[0075] Next, a control method for the fuel cell stack 22 and battery 27 in one embodiment of the present disclosure will be described with reference to Figures 5 and 8.

[0076] Figure 8 is a flowchart showing a control method for a fuel cell stack and battery in one embodiment of the present disclosure. In this embodiment, the control method for the fuel cell stack 22 and battery 27 is performed continuously, for example, after an operation is started by an operator, up to step S5.

[0077] With the hydrogen valve 24 open (Figure 5), the controller 30 controls the fuel cell stack 22 and the battery 27 respectively so that the remaining charge of the battery 27 is maintained at or above a predetermined charge level. Specifically, as shown in Figure 8, the charge level acquisition unit 30e acquires information regarding the remaining charge of the battery 27 from the battery 27 (step S9). The calculation unit 30b acquires information regarding the remaining charge of the battery 27 from the charge level acquisition unit 30e and acquires a predetermined charge level from the memory 30g. The predetermined charge level is the remaining charge of the battery 27 and is a predetermined charge level.

[0078] The calculation unit 30b determines whether the remaining charge of the battery 27 is less than or equal to a predetermined charge level (step S10). If it is determined that the remaining charge of the battery 27 is not less than or equal to the predetermined charge level (NO in step S10), the controller 30 repeats the execution of step S9. On the other hand, if it is determined that the remaining charge of the battery 27 is less than or equal to the predetermined charge level (YES in step S10), the calculation unit 30b outputs a signal indicating the determination result to the output control unit 30d.

[0079] Based on the determination that the remaining charge of the battery 27 is below a predetermined charge level, the output control unit 30d controls the fuel cell stack 22 so that the output of the fuel cell stack 22 increases (step S11). Specifically, the output control unit 30d controls the fuel cell stack 22 so that the amount of power output by the fuel cell stack 22 is greater than the amount of power required to drive each hydraulic actuator.

[0080] Based on the determination that the remaining charge level of the battery 27 is below a predetermined charge level, the output control unit 30d controls the battery 27 so that the amount of power output from the battery 27 is reduced (step S12). Specifically, the output control unit 30d controls the battery 27 so that the amount of power output by the battery 27 is less than the amount of power supplied to the battery 27 from the fuel cell stack 22. The output control unit 30d may also control the battery 27 so that it does not output any power. As a result of steps S11 and S12, a portion of the power output by the fuel cell stack 22 is charged into the battery 27.

[0081] The control method for the fuel cell and battery in this embodiment is then executed. Note that step S12 may be performed after step S10 and before step S11, or simultaneously with step S11.

[0082] In the above configuration, the tilt sensor 1 may continuously detect and output the tilt angle. In this case, the tilt acquisition unit 30a of the controller 30 continuously acquires the tilt angle from the tilt sensor 1. Alternatively, the tilt sensor 1 may temporarily detect and output the tilt angle. In this case, the tilt acquisition unit 30a of the controller 30 temporarily acquires the tilt angle from the tilt sensor 1.

[0083] As shown in Figure 5, the controller 30 may include, for example, a vehicle body controller 31 and a hydrogen controller 32. The vehicle body controller 31 and the hydrogen controller 32 may be made up of different circuit boards or may be provided as a single unit. The vehicle body controller 31 and the hydrogen controller 32 may have separate CPUs. The vehicle body controller 31 includes a tilt acquisition unit 30a, a calculation unit 30b, an output control unit 30d, a charge level acquisition unit 30e, a notification control unit 30f, and a memory 30g. The hydrogen controller 32 includes a valve control unit 30c.

[0084] The controller 30 includes a processor, main memory, and storage. The processor is, for example, a CPU (Central Processing Unit). The main memory includes, for example, non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory).

[0085] The controller 30 reads the program stored in the storage, loads it into the main memory, and executes predetermined processing according to the program. The program may also be distributed to the controller 30 via the network.

[0086] The controller 30 may be mounted on the work machine 100, or it may be located separately outside the work machine 100. If the controller 30 is located separately outside the work machine 100, the controller 30 may be wirelessly connected to the tilt sensor 1, hydrogen valve 24, fuel cell stack 22, battery 27, notification unit 36, etc. The controller 30 may be stored in a server located away from the work machine 100. The memory 30g may be provided separately from the controller 30.

[0087] In the above, the controller 30 may selectively set, for example, a high-power (Hi) driving mode and a low-power (Low) driving mode. The Hi driving mode and Low driving mode are driving modes of the vehicle 15. In the Hi driving mode, the upper limit of the amount of power output from the fuel cell stack 22 and the battery 27 is greater than the upper limit of the amount of power output from the fuel cell stack 22 and the battery 27 in the Low driving mode.

[0088] The upper limit power value may be the same as, for example, the upper limit of the amount of power output from the battery 27 in Low driving mode. In this case, after step S7, the controller 30 can only be set to Low driving mode.

[0089] In the above, the notification information may include, for example, information regarding the time during which the vehicle 15 can travel in both the Hi driving mode and the Low driving mode. In step S8, when the notification unit 36 ​​acquires the notification information, it may notify the time during which the vehicle 15 can travel in both the Hi driving mode and the Low driving mode.

[0090] In the above configuration, the calculation unit 30b may output information regarding the tilt angle of the main body 11 detected by the tilt sensor 1 to the notification control unit 30f. The notification control unit 30f may then notify the notification unit 36 ​​of the tilt angle of the main body 11 based on the information regarding the tilt angle obtained from the calculation unit 30b.

[0091] The tilt sensor 1 may also be capable of detecting the acceleration of the main unit 11. In this case, the tilt sensor 1 outputs information regarding the detected acceleration of the main unit 11 to the controller 30. The controller 30 may calculate the load (fatigue damage) applied to the hydrogen tank 21 based on the information regarding the acceleration of the main unit 11. The controller 30 may control the notification unit 36 ​​to issue a warning prompting the replacement of the hydrogen tank 21 if the fatigue damage exceeds a preset threshold.

[0092] In the above, the work machine 100 does not necessarily have a tilt sensor 1. In this case, the work machine system has a tilt measuring device (not shown) located outside the work machine 100. The tilt measuring device detects the tilt angle of the main body 11 and outputs information regarding the tilt angle of the main body 11 to the controller 30. The tilt measuring device and the main body 11 are connected, for example, by wireless.

[0093] <Effects> Next, the effects of this disclosure will be explained.

[0094] According to this embodiment, the controller 30 controls the opening and closing of the hydrogen valve 24 based on the tilt angle of the main body 11 detected by the tilt sensor 1. Therefore, the hydrogen valve 24 can be closed before the hydrogen system device, such as a fuel cell, tilts excessively. This stops the supply of hydrogen to the hydrogen system device. Consequently, even if an operational abnormality occurs in the hydrogen system device due to excessive tilting of the hydrogen system device, hydrogen leakage can be suppressed.

[0095] According to this embodiment, the hydrogen valve 24 is attached to the opening 92 of the hydrogen tank 21. Therefore, high-pressure hydrogen gas can be blocked at a position close to the hydrogen tank 21. This makes it possible to more reliably suppress hydrogen leakage in the event of an operational malfunction of the hydrogen system equipment.

[0096] According to this embodiment, the work machine 100 has a battery 27. The vehicle 15 of the main body 11 is powered by electricity supplied from at least one of the fuel cell stack 22 or the battery 27. Therefore, even when the fuel cell stack 22 cannot generate electricity because the hydrogen valve 24 is closed, the vehicle 15 can still be powered by electricity supplied from the battery 27. As a result, even after the hydrogen valve 24 is closed, the work machine 100 can be retracted to reduce the tilt of the main body 11.

[0097] According to this embodiment, when the hydrogen valve 24 is open, the controller 30 controls the fuel cell stack 22 and the battery 27 respectively to maintain the remaining charge of the battery 27 at or above a predetermined charge level. This makes it possible to sufficiently extend the time during which the vehicle 15 can operate when the hydrogen valve 24 is closed.

[0098] According to this embodiment, when the hydrogen valve 24 is closed, the controller 30 controls the battery 27 to adjust the amount of power output from the battery 27. Therefore, when the vehicle 15 is running on power supplied from the battery 27, it is possible to suppress an excessive decrease in the remaining charge of the battery 27. As a result, the time during which the vehicle 15 can run when the hydrogen valve 24 is closed can be sufficiently extended.

[0099] According to this embodiment, when the hydrogen valve 24 is closed, the controller 30 controls the notification unit 36 ​​to notify the operator of the remaining time that the vehicle 15 can operate using the power supplied from the battery 27. This allows the operator to easily understand the remaining time that the vehicle 15 can operate. Therefore, the operator can operate the work machine 100 to reduce the inclination of the main body 11 while the vehicle 15 is operational.

[0100] According to this embodiment, the controller 30 controls the hydrogen valve 24 to close when the tilt angle is greater than or equal to a first predetermined angle. The controller 30 controls the notification unit 36 ​​to issue a warning when the tilt angle is greater than or equal to a second predetermined angle which is smaller than the first predetermined angle. As a result, the operator can be notified of a warning regarding the tilt angle before the main body 11 tilts excessively. This prevents the main body 11 from tilting excessively.

[0101] In this embodiment, the tilt sensor 1 and the fuel cell stack 22 are included in the same vibration system. Therefore, the relative displacement between the tilt sensor 1 and the fuel cell stack 22 can be reduced. As a result, the tilt sensor 1 can accurately detect the tilt angle of the fuel cell stack 22. Consequently, excessive tilting of the fuel cell stack 22 can be suppressed more reliably.

[0102] According to this embodiment, the hydrogen tank 21 and the fuel cell stack 22 are contained within different vibration systems. This allows the vibrations of the hydrogen tank 21 and the fuel cell stack 22 to be suppressed using different damping mechanisms. This reduces damage to the hydrogen tank 21 and the fuel cell stack 22.

[0103] According to this embodiment, when the hydrogen valve 24 is closed, the controller 30 controls the fuel cell stack 22 to stop the operation of supplying hydrogen from the hydrogen tank 21 to the fuel cell stack 22. Therefore, it is possible to prevent the fuel cell stack 22 from supplying hydrogen when the hydrogen valve 24 is closed. This prevents an excessively large negative pressure from being applied to the flow path from the fuel cell stack 22 to the hydrogen valve 24. Consequently, damage to the hydrogen system equipment can be suppressed.

[0104] <Note> The embodiments described above include the following technical concepts.

[0105] (Note 1) A work machine comprising: a hydrogen power source which is a power source that utilizes hydrogen; a hydrogen tank which supplies hydrogen to the hydrogen power source; a hydrogen valve which opens and closes the hydrogen flow path from the hydrogen tank to the hydrogen power source; a vehicle body which supports the hydrogen power source and the hydrogen tank, respectively; and a controller which controls the opening and closing of the hydrogen valve based on the inclination angle of the vehicle body.

[0106] (Note 2) The work machine as described in Note 1, wherein the hydrogen tank has an internal space for storing hydrogen and an opening connecting the internal space to the outside of the hydrogen tank, and the hydrogen valve is attached to the opening.

[0107] (Note 3) The work machine according to Note 1 or Note 2, further comprising a battery, wherein the hydrogen power source is a fuel cell, and the vehicle body has a vehicle that runs on electricity supplied from at least one of the fuel cell or the battery.

[0108] (Note 4) The work machine according to Note 3, wherein the battery is charged by power supplied from the fuel cell, and when the hydrogen valve is open, the controller controls the fuel cell and the battery respectively so that the remaining charge of the battery is maintained at or above a predetermined charge level.

[0109] (Note 5) The work machine according to Note 3 or Note 4, wherein, when the hydrogen valve is closed, the controller controls the battery to adjust the amount of power output from the battery.

[0110] (Note 6) The work machine according to any one of Notes 3 to 5, further comprising a notification unit, wherein when the hydrogen valve is closed, the controller controls the notification unit to notify the amount of time the vehicle can be driven using the power supplied from the battery.

[0111] (Note 7) The work machine according to any one of Notes 1 to 5, further comprising a notification unit, wherein the controller controls the hydrogen valve to close when the inclination angle is greater than or equal to a predetermined first predetermined angle, and controls the notification unit to issue a warning when the inclination angle is greater than or equal to a predetermined second predetermined angle less than the first predetermined angle.

[0112] (Note 8) The work machine according to any one of Notes 1 to 7, further comprising a tilt sensor for detecting the tilt angle, wherein the tilt sensor and the hydrogen power source are included in the same vibration system.

[0113] (Note 9) The work machine described in any one of Notes 1 to 8, wherein the hydrogen tank and the hydrogen power source are contained in different vibration systems.

[0114] (Note 10) The work machine according to any one of Notes 1 to 9, wherein, when the hydrogen valve is closed, the controller controls the hydrogen power source to stop the operation of supplying hydrogen from the hydrogen tank to the hydrogen power source.

[0115] (Note 11) A method for controlling a work machine having a hydrogen power source, a hydrogen tank for supplying hydrogen to the hydrogen power source, a hydrogen valve for opening and closing a hydrogen flow path from the hydrogen tank to the hydrogen power source, and a vehicle body supporting the hydrogen power source and the hydrogen tank, the method comprising: detecting the inclination angle of the vehicle body, and closing the hydrogen valve when the inclination angle is greater than or equal to a first predetermined angle set in advance.

[0116] (Note 12) The control method for a work machine according to Note 11, wherein the hydrogen power source is a fuel cell, the work machine has a battery that is charged by electricity supplied from the fuel cell, and before the step of closing the hydrogen valve, the output of the fuel cell and the battery are controlled based on the remaining charge of the battery.

[0117] (Note 13) The method for controlling a work machine according to Note 11, wherein the work machine has a battery, and further comprises the step of adjusting the amount of power output from the battery when the inclination angle is greater than or equal to the first predetermined angle.

[0118] (Note 14) The control method for a work machine according to Note 11, wherein the hydrogen power source is a fuel cell, the work machine has a battery, the vehicle body has a vehicle that runs on electricity supplied from at least one of the fuel cell or the battery, and the method further comprises the step of notifying the amount of time the vehicle can run on electricity supplied from the battery when the inclination angle is greater than or equal to the first predetermined angle.

[0119] (Note 15) A control method for a work machine according to any one of Notes 11 to 14, further comprising the step of issuing a warning when the inclination angle is greater than or equal to a preset second predetermined angle that is smaller than the first predetermined angle and less than the first predetermined angle.

[0120] (Note 16) A control method for a work machine according to any one of Notes 11 to 15, further comprising the step of stopping the operation of the hydrogen power source to supply hydrogen from the hydrogen tank to the hydrogen power source when the inclination angle is greater than or equal to the first predetermined angle.

[0121] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended.

[0122] 1. Inclination sensor, 11. Main body, 12. Work machine, 13. Slewing body, 14. Cab, 14S. Driver's seat, 15. Driving body, 15Cr. Tracks, 15M. Driving motor, 16. Boom, 17. Arm, 18. Bucket, 19a. Boom cylinder, 19b. Arm cylinder, 19c. Bucket cylinder, 20. Slewing frame, 21. Hydrogen tank, 22. Fuel cell stack, 23. Pressure reducer, 24. Hydrogen valve, 25. Radiator, 26. Electric fan, 27. Battery, 28. Inverter, 30. Controller, 30a. Inclination acquisition unit, 30b. Calculation unit, 30c. Valve control unit, 30d. Output control unit, 30e. Charge level acquisition unit, 30g. Memory, 34. Electric motor, 35. Hydraulic pump, 36. Notification unit, 91. Internal space, 92. Opening, 100. Work machine, AR. Arrangement area, AT. Arm top pin, BF boom foot pin, BP base plate, BT boom top pin, CM column member, CU cooling unit, DM1, DM2 damping mechanism, FS fuel cell unit support mechanism, OP exterior panel, P1, P2, P3 connection part, RX slewing axis, SH stack hose, TF hydrogen tank support mechanism, TH tank hose, TP upper plate, UP lower plate, X front-to-back direction, Y left-to-right direction, Z up-and-down direction.

Claims

1. A work machine comprising: a hydrogen power source which is a power source that utilizes hydrogen; a hydrogen tank which supplies hydrogen to the hydrogen power source; a hydrogen valve which opens and closes the hydrogen flow path from the hydrogen tank to the hydrogen power source; a vehicle body which supports the hydrogen power source and the hydrogen tank, respectively; and a controller which controls the opening and closing of the hydrogen valve based on the inclination angle of the vehicle body.

2. The work machine according to claim 1, wherein the hydrogen tank has an internal space for storing hydrogen and an opening connecting the internal space to the outside of the hydrogen tank, and the hydrogen valve is attached to the opening.

3. The work machine according to claim 1 or 2, further comprising a battery, wherein the hydrogen power source is a fuel cell, and the vehicle body has a vehicle that runs on electricity supplied from at least one of the fuel cell or the battery.

4. The work machine according to claim 3, wherein the battery is charged by power supplied from the fuel cell, and when the hydrogen valve is open, the controller controls the fuel cell and the battery respectively to maintain the remaining charge of the battery at or above a predetermined charge level.

5. The work machine according to claim 3, wherein, when the hydrogen valve is closed, the controller controls the battery to adjust the amount of power output from the battery.

6. The work machine according to claim 3, further comprising a notification unit, wherein when the hydrogen valve is closed, the controller controls the notification unit to notify the amount of time the vehicle can operate using power supplied from the battery.

7. The work machine according to claim 1 or 2, further comprising a notification unit, wherein the controller controls the hydrogen valve to close when the tilt angle is greater than or equal to a predetermined first predetermined angle, and controls the notification unit to issue a warning when the tilt angle is greater than or equal to a predetermined second predetermined angle less than the first predetermined angle.

8. The work machine according to claim 1 or claim 2, further comprising a tilt sensor for detecting the tilt angle, wherein the tilt sensor and the hydrogen power source are included in the same vibration system.

9. The working machine according to claim 1 or claim 2, wherein the hydrogen tank and the hydrogen power source are contained in different vibration systems.

10. The work machine according to claim 1 or 2, wherein, when the hydrogen valve is closed, the controller controls the hydrogen power source to stop the operation of supplying hydrogen from the hydrogen tank to the hydrogen power source.

11. A work machine system comprising: a hydrogen power source which is a power source that utilizes hydrogen; a hydrogen tank which supplies hydrogen to the hydrogen power source; a hydrogen valve which opens and closes the hydrogen flow path from the hydrogen tank to the hydrogen power source; a vehicle body which supports the hydrogen power source and the hydrogen tank, respectively; and a controller which controls the opening and closing of the hydrogen valve based on the inclination angle of the vehicle body.

12. The work machine system according to claim 11, wherein the hydrogen tank has an internal space for storing hydrogen and an opening connecting the internal space to the outside of the hydrogen tank, and the hydrogen valve is attached to the opening.

13. The work machine system according to claim 11 or 12, further comprising a battery, wherein the hydrogen power source is a fuel cell, and the vehicle body has a vehicle that runs on electricity supplied from at least one of the fuel cell or the battery.

14. The work machine system according to claim 13, wherein the battery is charged by power supplied from the fuel cell, and when the hydrogen valve is open, the controller controls the fuel cell and the battery respectively to maintain the remaining charge of the battery at or above a predetermined charge level.

15. A control method for a work machine having a hydrogen power source, a hydrogen tank for supplying hydrogen to the hydrogen power source, a hydrogen valve for opening and closing a hydrogen flow path from the hydrogen tank to the hydrogen power source, and a vehicle body supporting the hydrogen power source and the hydrogen tank, the method comprising: detecting the inclination angle of the vehicle body; and closing the hydrogen valve when the inclination angle is greater than or equal to a first predetermined angle set in advance.

16. A method for controlling a work machine according to claim 15, wherein the hydrogen power source is a fuel cell, the work machine has a battery that is charged by electricity supplied from the fuel cell, and before the step of closing the hydrogen valve, the output of the fuel cell and the battery are controlled based on the remaining charge of the battery.

17. The method for controlling a work machine according to claim 15, wherein the work machine has a battery, and further comprises the step of adjusting the amount of power output from the battery when the tilt angle is greater than or equal to the first predetermined angle.

18. A control method for a work machine according to claim 15, wherein the hydrogen power source is a fuel cell, the work machine has a battery, the vehicle body has a vehicle that runs on electricity supplied from at least one of the fuel cell or the battery, and the method further comprises the step of notifying the amount of time the vehicle can run on electricity supplied from the battery when the inclination angle is greater than or equal to a first predetermined angle.

19. A control method for a work machine according to any one of claims 15 to 18, further comprising the step of issuing a warning when the inclination angle is greater than or equal to a preset second predetermined angle that is smaller than the first predetermined angle and less than the first predetermined angle.

20. A control method for a work machine according to any one of claims 15 to 18, further comprising the step of stopping the operation of the hydrogen power source to supply hydrogen from the hydrogen tank to the hydrogen power source when the inclination angle is greater than or equal to the first predetermined angle.

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