Work machine and method

Abstract

This work machine comprises: a work apparatus; a fuel cell supported by a vehicle body; a fan for cooling heat source equipment provided to the work machine; and a main control device. The main control device causes the fan to rotate by using electric power generated by the fuel cell when stopping the fuel cell.

Description

Work machine and method

[0001] This application claims priority to Japanese Patent Application No. 2024-055484, filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0002] As disclosed in Patent Document 1, a work machine equipped with a fuel cell system is known. The fuel cell generates electrical energy through a chemical reaction between hydrogen and oxygen. To operate the fuel cell, the fuel cell is provided with auxiliary devices such as a fuel pump for supplying hydrogen fuel and an air compressor.

[0003] Japanese Patent Application Laid-Open No. 2023-028066

[0004] When a fuel cell is shut down, if hydrogen remains in the anode and air remains in the cathode, the air and hydrogen may combine during the shutdown, creating an undesirable potential that can lead to oxidation and corrosion. Therefore, it is desirable to completely react the hydrogen and oxygen remaining in the fuel cell. This reaction generates electricity, which must be converted into thermal energy by a resistor, such as a retarder, for consumption.

[0005] An object of the present disclosure is to provide a work machine and method equipped with a fuel cell that can effectively utilize the electric power generated by the fuel cell when the fuel cell is stopped.

[0006] According to one aspect of the present invention, a work machine is provided with a work implement, and includes a fuel cell supported on a body of the work machine, a fan for cooling a heat source device provided in the work machine, and a main control device, wherein the main control device rotates the fan using electric power generated by the fuel cell when the fuel cell is stopped.

[0007] According to the above aspect, the work machine can effectively utilize the electric power generated by the fuel cell when the fuel cell is stopped.

[0008] Fig. 1 is a perspective view of a work machine according to a first embodiment; Fig. 2 is a schematic block diagram showing the configuration of a work machine according to a first embodiment; Fig. 3 is a schematic block diagram showing the configuration of a main control device according to a first embodiment; Fig. 4 is a flowchart showing stop processing of a work machine according to a first embodiment; Fig. 5 is a schematic block diagram showing the configuration of a computer according to an embodiment.

[0009] First Embodiment Configuration of Work Machine 1 Figure 1 is a perspective view of a work machine 1 according to the first embodiment. The work machine 1 according to the first embodiment is, for example, a hydraulic excavator. The work machine 1 includes a traveling body 110, a revolving body 120, a work implement 130, a driver's cab 140, and a machine room 150. The work machine 1, which is a hydraulic excavator, excavates earth and sand and levels the ground at a work site or the like. The traveling body 110 and the revolving body 120 form a vehicle body.

[0010] The running body 110 supports the work machine 1 so that it can travel. The running body 110 has a pair of left and right tracks. The work machine 1 moves forward, swing, or reverse by rotation of the pair of tracks. The rotating body 120 is supported on the running body 110 so that it can swing. The rotating body 120 swings relative to the running body 110 by an electric swing motor 322, which will be described later. The rotating body 120 supports the work implement 130, the operator's cab 140, the machine room 150, and the fuel cell system 20.

[0011] The work implement 130 is operably supported on the body of the work machine 1. The work implement 130 includes a boom 131, an arm 132, and an attachment 133 which is a working tool. The attachment 133 is an example of a working tool. In the example shown in FIG. 1 , the attachment 133 is a bucket. The base end of the boom 131 is rotatably attached to the rotating body 120. The base end of the arm 132 is rotatably attached to the tip of the boom 131. The attachment 133 is rotatably attached to the tip of the arm 132.

[0012] The work implement 130 is driven by a plurality of actuators, which include, for example, a boom cylinder 131C, an arm cylinder 132C, and an attachment cylinder 133C.

[0013] The boom cylinder 131C is a hydraulic cylinder for driving the boom 131. The base end of the boom cylinder 131C is attached to the revolving unit 120. The tip end of the boom cylinder 131C is attached to the boom 131. The arm cylinder 132C is a hydraulic cylinder for driving the arm 132. The base end of the arm cylinder 132C is attached to the boom 131. The tip end of the arm cylinder 132C is attached to the arm 132. The attachment cylinder 133C is a hydraulic cylinder for driving the attachment 133. The base end of the attachment cylinder 133C is attached to the arm 132. The tip end of the attachment cylinder 133C is attached to the attachment 133.

[0014] The cab 140 is where the operator of the work machine 1 gets in and operates and pilots the work machine 1. The cab 140 is located, for example, on the left side of the front end of the rotating bed 120. The cab 140 of the work machine 1 is equipped with an operating device 142 for operating the work machine 1, and a power switch 143.

[0015] The operating device 142 is operated by an operator to operate the work machine 1. The operating device 142 outputs an operating signal in response to operation by the operator. The power switch 143 is a switch for starting or stopping the operation of the work machine 1. The power switch 143 outputs a signal in response to operation by the operator. When the power switch 143 is operated while the work machine 1 is stopped, the power switch 143 outputs a start request signal. When the power switch 143 is operated while the work machine 1 is operating, the power switch 143 outputs a stop request signal. The power switch 143 may be, for example, a switch that outputs a start request signal when pressed by the operator when the work machine 1 is stopped, and that outputs a stop request signal when pressed by the operator when the work machine 1 is operating. Alternatively, for example, the power switch 143 may be a key switch that has a key cylinder into which a key can be inserted, and is operated by inserting the key into the key cylinder and turning the key from the off position, via the on position, to the start position. In this case, the power switch 143 may output a start request signal when the key is turned from the OFF position to the START position, and may output a stop request signal when the key is turned from the ON position to the OFF position. The power switch 143 may be, for example, a portable control device carried by an operator. When the operator operates the portable control device, wireless communication is established between the portable control device and the main control device 145, and the power switch 143 may output the start request signal upon establishment of communication. The portable control device may be, for example, a remote control key with an embedded electronic chip, or a portable computing device such as a smartphone or a personal digital assistant. The power switch 143 may be, for example, located in a remote location and configured to output the start request signal by remote control.

[0016] The main control device 145 controls the work machine 1. The main control device 145 receives operation signals from the operation device 142. Based on the operation signals from the operation device 142, the main control device 145 controls the travel of the traveling body 110, the drive of the work machine 130, and the swing operation of the swing body 120.

[0017] The main control device 145 receives a signal from the power switch 143. When the main control device 145 receives a start request signal from the power switch 143, the main control device starts the work machine 1. When the main control device 145 receives a start request signal from the power switch 143, the main control device 145 executes startup processing for each fuel cell module 21. When the main control device 145 receives a stop request signal from the power switch 143, the main control device 145 stops operation of the work machine 1. When the main control device 145 receives a stop request signal from the power switch 143, the main control device 145 executes shutdown processing for each fuel cell module 21.

[0018] The fuel cell system 20, which will be described later, is disposed in the machinery room 150. The machinery room 150 is disposed, for example, behind the operator's cab 140. The machinery room 150 forms a space in which the fuel cell system 20 is disposed.

[0019] 2 is a schematic block diagram showing the configuration of a work machine 1 according to the first embodiment. The work machine 1 includes a fuel cell system 20, a drive system 30, and a fan module 40. The fuel cell system 20 generates electric power for driving the work machine 1. The fuel cell system 20 generates electric power for driving the drive system 30. The electric power generated by the fuel cell system 20 is output to the drive system 30 via a bus B. The drive system 30 drives a work implement 130 and a traveling object 110 using the electric power generated by the fuel cell system 20.

[0020] The fuel cell system 20 includes a plurality of fuel cell modules 21 and a power storage device module 22 connected in parallel to a bus B.

[0021] Each fuel cell module 21 includes a fuel cell 211, a power converter 212, auxiliary equipment 213, and a fuel cell control device 214. The fuel cell 211 generates electricity by causing an electrochemical reaction between hydrogen and oxygen. The power converter 212 is, for example, a DC-DC converter, and is configured to be able to control the output of the power generated by the fuel cell 211. The power converter 212 converts the power generated by the fuel cell 211 and supplies it to the bus B. The auxiliary equipment 213 is a device for operating the fuel cell 211. The fuel cell module 21 includes, as the auxiliary equipment 213, a hydrogen pump for supplying hydrogen to the fuel cell 211, an air compressor for generating compressed air to be supplied to the fuel cell 211, and a water pump for supplying cooling water to cool the fuel cell 211. The fuel cell control device 214 controls the fuel cell module 21 in accordance with commands from the main control device 145. The fuel cell control device 214 monitors the status of the fuel cell 211 and outputs data indicating the status of the fuel cell 211 to the main control device 145. The fuel cell control device 214 outputs, for example, data indicating changes in the output voltage of the fuel cell 211 to the main control device 145. The fuel cell control device 214 is an example of a monitoring device.

[0022] The power storage device module 22 includes a power storage device 221 and a power converter 222. The power storage device 221 is configured to be able to charge or discharge surplus power from the bus B. The power converter 222 is, for example, a DC-DC converter, and controls the input and output of power to the power storage device 221. The power converter 222 outputs power from the power storage device 221 in accordance with a command from the main control device 145. The power converter 222 inputs power from the bus B to charge the power storage device 221 in accordance with a command from the main control device 145. The power storage device 221 is, for example, a capacitor.

[0023] The drive system 30 includes a hydraulic drive module 31 and a slewing module 32 .

[0024] The hydraulic drive module 31 includes an inverter 311, an electric pump motor 312, a hydraulic pump 313, and a hydraulic actuator 314. The inverter 311 converts DC current from the bus B into three-phase AC current and supplies it to the electric pump motor 312. The electric pump motor 312 generates power for driving the work machine 130 and the traveling vehicle 110. The electric pump motor 312 is rotated by the supplied three-phase AC current and drives the hydraulic pump 313. The hydraulic pump 313 discharges hydraulic oil to be supplied to the hydraulic actuator 314. The hydraulic oil discharged from the hydraulic pump 313 is supplied to the hydraulic actuator 314 via a control valve (not shown). The hydraulic actuator 314 is driven by the supplied hydraulic oil. The hydraulic actuator 314 includes a boom cylinder 131C, an arm cylinder 132C, an attachment cylinder 133C, and a traveling motor 134. The rotational force generated by the traveling motor 134 is transmitted to the traveling body 110 .

[0025] The swing module 32 includes an inverter 321 and an electric swing motor 322. The inverter 321 converts DC current from the bus B into three-phase AC current and supplies it to the electric swing motor 322. The electric swing motor 322 generates power for swinging the swing unit 120. The electric swing motor 322 rotates by the supplied three-phase AC current, causing the swing unit 120 to swing relative to the traveling unit 110.

[0026] The fan module 40 is configured to cool components (heat source equipment) that generate heat during operation. The fan module 40 includes a power converter 401, an electric fan motor 402, an electric fan control device 403, and a fan 404. The fan 404 according to the first embodiment cools the fuel cell 211 by blowing air to a radiator 405 that cools the refrigerant circulating through the multiple fuel cell modules 21. The fan 404 may also blow air directly to the fuel cell 211. The fan module 40 is not limited to a fan module for cooling the fuel cell 211. The fan 404 may also cool hydraulic oil by blowing air to a heat exchanger that cools hydraulic oil. The fan 404 may also be a fan module for cooling other heat source equipment, such as electrical components. The power converter 401 is, for example, a DC-DC converter, and converts power from the bus B into power capable of driving the electric fan motor 402 and supplies the power to the electric fan motor 402. That is, the electric fan motor 402 according to the first embodiment is a DC motor driven by a direct current. In other embodiments, the electric fan motor 402 may be an AC fan, and the power converter 401 may be an inverter. The electric fan control device 403 controls the electric fan motor 402 and the power converter 401 according to commands from the main control device 145. The electric fan control device 403 can switch the rotation direction of the fan 404 between a forward direction (first direction) and a reverse direction (second direction). For example, the electric fan control device 403 may switch the rotation direction of the fan 404 between the forward direction and the reverse direction by switching the direction of the current supplied from the power converter 401 to the electric fan motor 402. The fan 404 according to the first embodiment is configured to rotate in the forward direction to draw outside air into the machine room 150 and cool the radiator 405. In addition, the fan 404 according to the first embodiment is configured to rotate in the reverse direction to exhaust the air inside the machine room 150 to the outside and blow away dust adhering to the radiator 405.

[0027] 3 is a schematic block diagram showing the configuration of the main control device 145 according to the first embodiment. The main control device 145 includes a receiving unit 501, a fuel cell control unit 502, a power storage device control unit 503, and a fan control unit 504.

[0028] The receiving unit 501 receives measurement data from a measuring device 161 provided on the work machine 1. The measuring device 161 receives measurement data related to the operating state of the work machine 1. The measuring device 161 receives various measurement data indicating the state of the work machine 1. The measuring device 161 includes, for example, a fuel gauge for measuring the charging rate of the power storage device 221, a current sensor for measuring the current passing through the power converter 401, and a voltage sensor for measuring the voltage of the bus B. The receiving unit 501 receives an operation signal from the operating device 142. The receiving unit 501 receives a start request signal and a stop request signal from the power switch 143. The receiving unit 501 receives data indicating the state of the fuel cell 211 from the fuel cell control device 214.

[0029] The fuel cell control unit 502 generates commands for controlling the fuel cell module 21. The fuel cell control unit 502 generates power control commands for controlling the output of the fuel cell module 21. The fuel cell control unit 502 generates a start command for causing the fuel cell module 21 to execute a start process, based on a start request signal from the power switch 143. The fuel cell control unit 502 generates a stop command for causing the fuel cell module 21 to execute a stop process, based on a stop request signal from the power switch 143. The fuel cell control unit 502 outputs the generated command signal to the fuel cell control device 214 of the fuel cell module 21.

[0030] The power storage device control unit 503 generates a power control command for controlling the input and output of power to and from the power storage device 221. The power storage device control unit 503 outputs the generated command signal to the power converter 222 of the power storage device module 22.

[0031] The fan control unit 504 generates a command for controlling the rotation of the fan 404. The fan control unit 504 generates a drive command for controlling the electric fan motor 402 and the power converter 401. The fan control unit 504 outputs the generated command signal to the electric fan control device 403 of the fan module 40.

[0032] <<Control When Stopping Work Machine 1>> Figure 4 is a flowchart showing the shutdown process for the work machine 1 according to the first embodiment. When the operator operates the power switch 143 while the work machine 1 is running, the power switch 143 outputs a shutdown request signal to the main control device 145 to stop the work machine 1. When the receiving unit 501 of the main control device 145 receives the shutdown request signal from the power switch 143, the main control device 145 shuts down the fuel cell system 20 in the following procedure.

[0033] First, the fuel cell control unit 502 outputs a power control command to the fuel cell control devices 214 of all fuel cell modules 21 to set the output power to zero (step S1).

[0034] Next, the fuel cell control unit 502 determines the number of fuel cell modules 21 required to generate the power required to drive the electric fan motor 402 (step S2). The range (upper and lower limits) of the power required to drive the electric fan motor 402 and the power generated during the shutdown process of the fuel cell modules 21 can be calculated based on the design values ​​of the electric fan motor 402 and the fuel cell modules 21, respectively. The fuel cell control unit 502 according to the first embodiment calculates the number of fuel cell modules 21 required to generate the power required to drive the electric fan motor 402 based on the range (upper and lower limits) of the power required to drive the electric fan motor 402 and the power generated during the shutdown process of the fuel cell modules 21. Note that if the power generated during the shutdown process of the fuel cell modules 21 varies depending on factors such as the outside temperature and the operating time, the fuel cell control unit 502 may calculate the required number of fuel cell modules 21 using the average value of the power generated during the shutdown process. Furthermore, the fuel cell control unit 502 according to other embodiments may correct the power generated by the fuel cell modules 21 based on the outside temperature and the operating time.

[0035] Next, the fuel cell control unit 502 determines a set of fuel cell modules 21 to be shut down from among the plurality of fuel cell modules 21 (step S3). The number of fuel cell modules 21 constituting one set is equal to the number determined in step S2. Note that the fuel cell control unit 502 according to the first embodiment may randomly determine the set of fuel cell modules 21 to be shut down.

[0036] The fuel cell control unit 502 generates a stop command to cause the fuel cell module 21 to execute the stop process, and outputs the stop command to the fuel cell control device 214 of each fuel cell module 21 relating to the group determined in step S3 (step S4). The fuel cell control unit 502 outputs the stop command to the fuel cell control device 214 of the fuel cell module 21 to be stopped, so as to stop the number of fuel cell modules 21 determined based on the range of power required to rotate the fan 404.

[0037] When the fuel cell control device 214 of the fuel cell module 21 to be shut down receives the shutdown command output in step S4, it executes a predetermined shutdown process to shut down the fuel cell 211 (step S5). For example, the fuel cell control device 214 of the fuel cell module 21 to be shut down executes the shutdown process in the following procedure. The fuel cell control device 214 stops the hydrogen pump, which is the auxiliary device 213, and uses an air compressor to compress air into the fuel cell 211, causing the hydrogen remaining in the fuel cell 211 to react with oxygen in the air. At this time, the fuel cell 211 generates electricity through the reaction between the remaining hydrogen and oxygen. The fuel cell control device 214 controls the power converter 212 to supply the power generated by the fuel cell 211 to the bus B. The fuel cell control device 214 monitors the power generated by the fuel cell 211 and continues generating power until the generated power falls below a predetermined value. When the generated power falls below the predetermined value, the fuel cell control device 214 shuts down all of the auxiliary devices 213 and the power converter 212. This allows the fuel cell control device 214 to stop the fuel cell 211 after the hydrogen remaining in the fuel cell 211 has completely reacted.

[0038] The fan control unit 504 generates a drive command to rotate the fan 404 in the reverse direction and outputs the drive command to the electric fan control device 403 (step S6). The electric fan control device 403 controls the power converter 401 and the electric fan motor 402 so that the fan 404 rotates in the reverse direction. The power converter 401 uses the power generated by the fuel cell 211 in step S5 to drive the electric fan motor 402 to rotate in the reverse direction. The electric fan motor 402 rotates the fan 404 in the reverse direction. This allows the fan 404 to blow away dust adhering to the radiator 405.

[0039] Next, the fuel cell control unit 502 determines whether there are any fuel cell modules 21 for which the shutdown process has not been completed (step S7). If there are any fuel cell modules 21 for which the shutdown process has not been completed (step S7: YES), the fuel cell control unit 502 determines the next set of fuel cell modules 21 to be shut down (step S8).

[0040] As in step S4, the fuel cell control unit 502 generates a stop command to cause the fuel cell module 21 to perform the shutdown process, and outputs the stop command to the fuel cell control device 214 of each fuel cell module 21 in the group determined in step S8 (step S9). Note that the fuel cell control unit 502 according to the first embodiment may output a stop command to the fuel cell control device 214 of each fuel cell module 21 in the group determined in step S8 after determining that the fuel cell module 21 in the previous group has shut down. The fuel cell control unit 502 may determine that the fuel cell module 21 in the previous group has shut down based on data indicating the state of the fuel cell 211 received by the receiving unit 501. The fuel cell control unit 502 may also predict the time required to shut down the fuel cell module 21 in the previous group, and output a stop command to the fuel cell control device 214 of each fuel cell module 21 in the group determined in step S8 after the predicted time has elapsed. For example, the fuel cell control unit 502 may monitor changes in the output voltage of the fuel cell module 21 to predict the time required for the shutdown process. Furthermore, if the time required for shutting down the fuel cell modules 21 varies depending on factors such as the outside temperature or the operating time, the fuel cell control unit 502 may set the average time required for shutting down the fuel cell modules 21 as the time required for shutting down the fuel cell modules 21 in advance. Furthermore, the fuel cell control unit 502 may start shutting down the next group of fuel cell modules 21 without waiting for the previous group of fuel cell modules 21 to have shut down. This allows the main control unit 145 to prevent or minimize a period of no power generation between the completion of the shutdown process for the previous group and the start of the shutdown process for the next group. The main control unit 145 may also control the timing of shutting down the fuel cell modules 21 so that the generated power supplied to the bus B does not become zero.

[0041] When the fuel cell control device 214 of the fuel cell module 21 to be shut down receives the shutdown command output in step S9, it executes a predetermined shutdown process to shut down the fuel cell 211, similar to step S5 (step S10). Thereafter, the process returns to step S7.

[0042] On the other hand, if there is no fuel cell module 21 for which the shutdown process has not been completed (step S7: NO), the fan control unit 504 outputs a stop command to the electric fan control device 403 to stop the rotation of the fan 404 (step S11), thereby stopping the operation of the work machine 1.

[0043] <<Actions and Effects>> As described above, the main control device 145 according to the first embodiment functions as follows. When the fuel cell 211 is shut down, the main control device 145 rotates the fan 404 in the reverse direction using the electric power generated by the reaction between oxygen and hydrogen remaining in the fuel cell 211. This allows the work machine 1 to use the electric power generated when the fuel cell 211 is shut down to blow away debris adhering to the radiator 405. In other words, the work machine 1 according to the first embodiment can effectively utilize the electric power generated by the fuel cell 211 when the fuel cell 211 is shut down. Furthermore, for example, when the electric power generated when the fuel cell 211 is shut down is charged to the power storage device 221, power conversion loss occurs. However, the work machine 1 according to the first embodiment directly uses the electric power generated when the fuel cell 211 is shut down to drive the fan 404, thereby achieving high power efficiency. Furthermore, according to the work machine 1 according to the first embodiment, because debris adhering to the radiator 405 is blown away when the operation of the work machine 1 is shut down, clogging of the radiator 405 can be suppressed, and a decrease in cooling performance can be suppressed. As a result, the work machine 1 according to the first embodiment can reduce maintenance time.

[0044] Note that a work machine 1 according to another embodiment may supply the electric power generated when the fuel cell 211 is stopped to a fan module for cooling other heat source equipment such as electrical components or a heat exchanger for cooling hydraulic oil. In this case as well, the work machine 1 can effectively utilize the electric power generated by the fuel cell 211 when the fuel cell 211 is stopped.

[0045] Note that, during the shutdown process of the fuel cell module 21, the main control device 145 according to another embodiment may use the power generated by the shutdown process to rotate the fan 404 in the forward direction rather than the reverse direction. In this case, the fuel cell module 21 can be cooled by the air blown by the fan 404. In this case as well, the work machine 1 can effectively utilize the power generated by the fuel cell 211 when the fuel cell 211 is shut down.

[0046] The work machine 1 according to the first embodiment is equipped with one fan module 40, but is not limited to this. For example, a work machine 1 according to other embodiments may be equipped with multiple fan modules 40. If the work machine 1 is equipped with multiple fan modules 40, the main control device 145 may control all of the fans 404 to rotate simultaneously when the fuel cell 211 is stopped, or may control only a predetermined number of the fans 404 to rotate.

[0047] Furthermore, the main control device 145 according to the first embodiment sequentially stops the plurality of fuel cell modules 21 so that the power generated when the fuel cell 211 is stopped falls within the range of power required to rotate the electric fan motor 402. This allows the main control device 145 to supply just the right amount of power for controlling the rotation of the electric fan motor 402.

[0048] Furthermore, the main control device 145 according to the first embodiment controls the timing of the shutdown process of the multiple fuel cell modules so that the generated power supplied to the bus B does not become zero. As a result, the main control device 145 prevents the electric fan motor 402 from rotating intermittently, and can efficiently blow away dust adhering to the radiator 405.

[0049] <Other Embodiments> One embodiment has been described in detail above with reference to the drawings, but the specific configuration is not limited to that described above, and various design modifications and the like are possible. For example, the main control device 145 according to the embodiment described above may be configured by a single computer, or the configuration of the main control device 145 may be divided into multiple computers that function as the main control device 145 by cooperating with each other. In this case, some of the computers that make up the main control device 145 may be installed inside the work machine 1, and other computers may be provided external to the work machine 1.

[0050] Furthermore, the work machine 1 according to the embodiment described above may be remotely operated. In this case, the main control device 145 may be configured by a computer provided external to the work machine 1. Furthermore, the work machine 1 according to the embodiment described above may be controlled by a control system located in a remote location. In this case, the main control device 145 may be configured by a computer that constitutes the control system.

[0051] Furthermore, the main control device 145 according to the above-described embodiment may have the functions of the fuel cell control device 214. In this case, each fuel cell module 21 may not have the fuel cell control device 214, and the power converters 212 and auxiliary devices 213 of each fuel cell module 21 may operate based on command signals from the main control device 145. Furthermore, the main control device 145 may function as a monitoring device and have the function of monitoring the state of the fuel cells 211.

[0052] Furthermore, although the work machine 1 according to the embodiment described above is a hydraulic excavator, this is not limiting. For example, the work machine 1 according to other embodiments may be another work machine such as a wheel loader or a dump truck.

[0053] Furthermore, in the above-described embodiment, a capacitor is given as an example of the power storage device 221, but this is not limiting. For example, the power storage device 221 of the work machine 1 according to other embodiments may be a battery.

[0054] Furthermore, the fan 404 according to the embodiment described above is configured to rotate in the reverse direction to exhaust air from inside the machine chamber 150 to the outside and blow away dust adhering to the radiator 405, but is not limited to this. For example, the fan 404 according to another embodiment may be configured to rotate in the reverse direction to take in outside air into the machine chamber 150 and blow away dust adhering to the radiator 405.

[0055] Furthermore, although the main control device 145 according to the embodiment described above randomly determines the pair of fuel cell modules 21 to be shut down, this is not limiting. For example, the main control device 145 according to another embodiment may determine the pair of fuel cell modules 21 to be shut down based on the degree of deterioration of the fuel cells 211. In this case, the main control device 145 may determine the pair of fuel cell modules 21 to be shut down in order of the fuel cell modules 21 with the greatest degree of deterioration of the fuel cells 211. Furthermore, the main control device 145 according to another embodiment may randomly determine the pair of fuel cell modules 21 to be shut down next time when the shutdown process has been performed more than a predetermined number of times. For example, in a work machine 1 having four fuel cell modules A-D, if the pair of A and B and the pair of C and D have been shut down a predetermined number of times, the pair of fuel cell modules 21 to be shut down next time may be determined to be the pair of A and D and the pair of B and C. Furthermore, the main control device 145 according to another embodiment may determine the set of fuel cell modules 21 to be shut down so as to rotate the set of fuel cell modules 21 that will be first subjected to the shutdown process and the set of fuel cell modules 21 that will be last subjected to the shutdown process. For example, in a work machine 1 having four fuel cell modules A-D, if the first set that was last subjected to the shutdown process was A and B and the last set was C and D, the first set that will be next subjected to the shutdown process may be determined to be C and D, and the last set to be A and B.

[0056] In step S2 of the flowchart shown in Fig. 4, the main control device 145 according to the embodiment described above identifies the number of fuel cell modules 21 required to generate the power required to drive the electric fan motor 402. On the other hand, in another embodiment, if it is known in advance that the power required to drive the electric fan motor 402 can be covered by the power generated during the shutdown process of one fuel cell module 21, the main control device 145 does not need to identify the number of fuel cell modules 21 required in step S2 or determine the set of fuel cell modules to be shut down in step S3.

[0057] <Computer Configuration> Fig. 5 is a schematic block diagram showing the configuration of a computer according to an embodiment. The computer 90 includes a processor 91, a main memory 92, a storage 93, and an interface 94. The main control device 145 and the fuel cell control device 214 described above are implemented in the computer 90. The operations of the above-described processing units are stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it into the main memory 92, and executes the above-described processing in accordance with the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to the above-described storage units in accordance with the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0058] The program may be for implementing some of the functions to be performed by the computer 90. For example, the program may be implemented in combination with other programs already stored in storage or in combination with other programs implemented in other devices. In another embodiment, the computer 90 may include a custom large-scale integrated circuit (LSI) such as a programmable logic device (PLD) in addition to or instead of the above configuration. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also an example of a processor. In another embodiment, the computer 90 may be virtualized on one or more computers.

[0059] Examples of storage 93 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 94 or a communication line. Furthermore, when this program is distributed to computer 90 via a communication line, computer 90 that receives the program may load the program into main memory 92 and execute the above-described processing. In at least one embodiment, storage 93 is a non-transitory tangible storage medium.

[0060] The program may also be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 93.

[0061] According to the above aspect, the work machine can effectively utilize the electric power generated by the fuel cell when the fuel cell is stopped.

[0062] 1...Work machine 110...Traveling body 120...Swinging body 130...Working machine 131...Boom 131C...Boom cylinder 132...Arm 132C...Arm cylinder 133...Attachment 133C...Attachment cylinder 134...Travel motor 140...Driver's cab 142...Operating device 143...Power switch 145...Main control device 20...Fuel cell system 21...Fuel cell module 211...Fuel cell 212...Power converter 213...Auxiliary device 214...Fuel cell control device 22...Electricity storage device module 221...Electricity storage device 222...Power converter 30...Drive system 31...Hydraulic drive module 311...Inverter 312...Electric pump motor 313...Hydraulic pump 314...Hydraulic actuator 32...Swing module 321...Inverter 322...Electric swing motor 40...Fan module 401...Power converter 402: Electric fan motor 403: Electric fan control device 404: Fan 501: Receiving unit 502: Fuel cell control unit 503: Power storage device control unit 504: Fan control unit B: Bus bar

Claims

1. A work machine equipped with a working implement, comprising: a fuel cell supported on a body of the work machine; a fan for cooling heat source equipment equipped in the work machine; and a main control device, wherein the main control device rotates the fan using electricity generated by the fuel cell when the fuel cell is stopped.

2. The work machine according to claim 1, wherein the fan cools the heat source equipment by rotating in a first direction, and the main control device rotates the fan in a second direction different from the first direction using the electric power generated by the fuel cell when the fuel cell is stopped.

3. A work machine as described in claim 1, comprising a plurality of fuel cells including the fuel cell, and wherein the main control device sequentially stops the plurality of fuel cells so that the generated power falls within the range of power required to rotate the fan.

4. The work machine according to claim 3, wherein the main control device simultaneously stops a number of the fuel cells determined based on the range of power required to rotate the fan.

5. A work machine according to claim 3, wherein the main control device controls the timing of the shutdown process of the plurality of fuel cells so that the power generated by the fuel cells does not become zero.

6. A method for a work machine that includes a work implement, a fuel cell supported on a vehicle body, and a fan for cooling a heat source device provided on the vehicle body, wherein the fan is rotated using the electric power generated by the fuel cell when the fuel cell is stopped.

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