Vehicle for work

Abstract

To provide technique which can operate a work device even without charging a power storage device by an external unit.SOLUTION: A vehicle for work makes it possible to travel by power of an engine and comprises a power generator which electrically generates electrical power by operating by the power of the engine, a converter which transforms direct-current voltage of the electrical power electrically generated by the power generator, a power storage device for work which stores the electrical power of which the voltage is transformed by the converter and a work device which is capable of executing prescribed work by operating by the electrical power supplied from the power storage device for work.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to work vehicles. [Background technology]

[0002] Patent Document 1 discloses a construction machine. The construction machine of Patent Document 1 includes an engine, an electric motor mechanically connected to the engine, a power storage device, and an inverter that is provided between the power storage device and the electric motor and converts electric power. In the configuration of Patent Document 1, the power storage device supplies electric power to the electric motor, or charges the electric power generated by the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-182920 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the construction machine of Patent Document 1, power may be supplied from an external device to the power storage device in order to charge the power storage device. This specification provides a technique that allows the work implement to operate without charging the power storage device by an external device. [Means for solving the problem]

[0005] A first aspect of the present technology relates to a work vehicle capable of running on engine power. The work vehicle may include a power generation device that operates on the engine power to generate electric power, a converter that transforms a DC voltage of the electric power generated by the power generation device, a work power storage device that stores the electric power whose voltage has been transformed by the converter, and a work device that operates on electric power supplied from the work power storage device to perform a predetermined work.

[0006] According to this configuration, the DC voltage of the electric power generated by the power generation device can be transformed and supplied to the working power storage device, thereby making it possible to operate the working device without charging the working power storage device by an external device.

[0007] In a second aspect, in the above first aspect, the work vehicle may further include a vehicle power storage device that stores power supplied from the power generation device without passing through the converter, a first switch that opens and closes an electric circuit connecting the power generation device and the vehicle power storage device, a second switch that opens and closes an electric circuit connecting the power generation device and the work power storage device via the converter, and a control device capable of executing control to switch between a first state in which the first switch is on and the second switch is off, and a second state in which the second switch is on and the first switch is off.

[0008] According to this configuration, by switching between the first state and the second state, it is possible to selectively switch between charging the vehicle power storage device and charging the work power storage device.

[0009] In a third aspect, in the above second aspect, the control device may be capable of switching to the first state when the storage amount of the vehicle power storage device is less than a predetermined first reference storage amount when the engine is operating, and may be capable of switching to the second state when the storage amount of the work power storage device is less than a predetermined second reference storage amount.

[0010] According to this configuration, each of the power storage devices can be charged in accordance with the amount of stored power in the vehicle power storage device and the work power storage device.

[0011] In a fourth aspect, in the second aspect, the control device may start the engine when the amount of electricity stored in the vehicle power storage device becomes less than a predetermined first reference amount of electricity stored, or when the amount of electricity stored in the work power storage device becomes less than a predetermined second reference amount of electricity stored, while the engine is stopped. The control device may be capable of switching to the first state when the amount of electricity stored in the vehicle power storage device is less than the first reference amount of electricity stored, while the engine is operating, and may be capable of switching to the second state when the amount of electricity stored in the work power storage device is less than the second reference amount of electricity stored.

[0012] According to this configuration, even if the storage amount of the vehicle storage device or the work storage device decreases while the engine is stopped, by starting the engine, each storage device can be charged according to the storage amount of the vehicle storage device and the work storage device.

[0013] In a fifth aspect, in the second aspect, the control device may be capable of switching to the first state when the amount of electricity stored in the vehicle power storage device is less than a predetermined first reference amount of electricity stored when the engine speed is less than a predetermined reference amount of electricity stored when the engine speed is less than a predetermined reference amount of electricity stored when the engine speed is equal to or greater than the reference amount of electricity stored when the engine speed is less than a predetermined ...

[0014] According to this configuration, it is possible to selectively switch between charging the vehicle power storage device and charging the work power storage device in accordance with the engine speed.

[0015] In a sixth aspect, in the second aspect described above, the work vehicle may further include a third switch that opens and closes an electric path that connects the vehicle power storage device and the work power storage device via the converter. The control device may be capable of executing control to switch between the first state in which the first switch is on and the second switch and the third switch are off, the second state in which the second switch is on and the first switch and the third switch are off, and the third state in which the third switch is on and the first switch and the second switch are off.

[0016] According to this configuration, by switching between the first state, the second state, and the third state, it may be possible to selectively switch between charging from the power generation device to the vehicle power storage device, charging from the power generation device to the work power storage device, and charging from the vehicle power storage device to the work power storage device.

[0017] In a seventh aspect, in the sixth aspect described above, the control device may switch to the third state when the amount of electricity stored in the work-use electricity storage device becomes less than a predetermined third reference electricity storage amount while the engine is stopped, and when the amount of electricity stored in the vehicle electricity storage device is equal to or greater than a predetermined fourth reference electricity storage amount.

[0018] According to this configuration, even if the amount of electricity stored in the work-use power storage device decreases while the engine is stopped, if the amount of electricity stored in the vehicle-use power storage device is sufficient, electricity can be charged from the vehicle-use power storage device to the work-use power storage device.

[0019] An eighth aspect of the present technology relates to a work vehicle capable of traveling by engine power. The work vehicle may include a power generation device that operates by engine power to generate electric power, a vehicle power storage device that stores the electric power generated by the power generation device, a work electric power storage device having an output voltage different from that of the vehicle power storage device, a work device that operates by electric power supplied from the vehicle power storage device or electric power supplied from the work electric power storage device to perform a predetermined work, a converter that transforms a DC voltage of the electric power supplied from the vehicle power storage device to the work device, and a control device. The work device may be capable of performing the predetermined work in a first mode in which it operates by electric power supplied from the vehicle power storage device via the converter, and a second mode in which it operates by electric power supplied from the work electric power storage device without passing through the converter. When a predetermined start request is obtained from the working device while the engine is stopped, the control device may start the working device in the first mode, and when a predetermined switching condition is satisfied, the control device may switch from the first mode to the second mode and operate the working device in the second mode.

[0020] According to this configuration, when the working device is started, power is first supplied from the vehicle power storage device to the working device, and then power is supplied from the work power storage device to the working device, thereby suppressing the generation of inrush current in the working device. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a functional block diagram of the work vehicle of the first embodiment. [Diagram 2] FIG. 11 is a functional block diagram of a work vehicle according to a modified example. [Diagram 3] 13 is a flowchart of a first process. [Figure 4] 13 is a flowchart of a first modification of the first process. [Diagram 5] 13 is a flowchart of a second modified example of the first process. [Figure 6] 11 is a flowchart of a second process. [Figure 7] 13 is a flowchart of a third process. [Figure 8] FIG. 11 is a functional block diagram of a work vehicle according to a second embodiment. [Figure 9] 13 is a flowchart of a fourth process. [Figure 10] FIG. 11 is a functional block diagram of a work vehicle according to a third embodiment. [Figure 11] 13 is a flowchart of a fifth process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Example 1 A work vehicle 2 of the first embodiment will be described with reference to the drawings. As shown in Fig. 1, the work vehicle 2 of the first embodiment includes a vehicle body 10, an engine 12, a power generation device 14, a vehicle power storage device 20, a work power storage device 22, and a converter 24. The work vehicle 2 also includes an inverter 26, a work device 30, and a control device 50.

[0023] The work vehicle 2 is, for example, a pump vehicle that performs work to pump a fluid (for example, water). The work vehicle 2 is capable of traveling using the power of an engine 12. A vehicle body 10 is equipped with the engine 12, a power generation device 14, a vehicle power storage device 20, a work power storage device 22, a converter 24, an inverter 26, a work device 30, a control device 50, and the like.

[0024] The engine 12 of the work vehicle 2 is, for example, a gasoline engine. The engine 12 of the work vehicle 2 operates using combustion energy of fuel (for example, gasoline). The rotation speed of the engine 12 is detected by a rotation speed sensor 64. Information on the rotation speed of the engine 12 detected by the rotation speed sensor 64 is transmitted to the control device 50. The rotation speed sensor 64 is attached to the engine 12, for example.

[0025] The engine 12 may be mechanically connected to a motor 32 of a working device 30 (described later) via a clutch 16. In this configuration, when the clutch 16 is turned on, the engine 12 and the motor 32 are connected, and when the clutch 16 is turned off, the engine 12 and the motor 32 are disconnected.

[0026] The power generating device 14 is mechanically connected to the engine 12, and operates using the power of the engine 12 to generate electric power. The power generating device 14 generates and outputs DC power. More specifically, the power generating device 14 converts AC power generated using the power of the engine 12 into DC power and outputs it. The power generating device 14 is sometimes called an alternator.

[0027] The vehicle power storage device 20 can store electric power generated by the power generation device 14. The vehicle power storage device 20 is electrically connected to the power generation device 14 via a first electric circuit 71. Electric power is supplied from the power generation device 14 to the vehicle power storage device 20 via the first electric circuit 71. This charges the vehicle power storage device 20. The vehicle power storage device 20 is, for example, a lead storage battery, a nickel metal hydride battery, a lithium ion battery, or the like.

[0028] The amount of stored electricity in the vehicle power storage device 20 is detected by a first stored electricity amount sensor 61. Information on the amount of stored electricity in the vehicle power storage device 20 detected by the first stored electricity amount sensor 61 is transmitted to the control device 50. The first stored electricity amount sensor 61 is attached to the vehicle power storage device 20, for example.

[0029] A first switch 41 is disposed on a first electric circuit 71 connecting the power generation device 14 and the vehicle power storage device 20. The power generation device 14 and the vehicle power storage device 20 are electrically connected via the first switch 41. The first switch 41 opens and closes the first electric circuit 71 between the power generation device 14 and the vehicle power storage device 20. When the first switch 41 is turned on (closed), the power generation device 14 and the vehicle power storage device 20 are electrically connected, and when the first switch 41 is turned off (open), the power generation device 14 and the vehicle power storage device 20 are electrically disconnected. When the first switch 41 is turned on (closed) while the power generation device 14 is operating, the power generated by the power generation device 14 is charged to the vehicle power storage device 20.

[0030] The vehicle power storage device 20 is electrically connected to, for example, auxiliary equipment (not shown) of the work vehicle 2. The vehicle power storage device 20 can supply stored electric power to the auxiliary equipment of the work vehicle 2. Electric power discharged from the vehicle power storage device 20 is supplied to the auxiliary equipment. The vehicle power storage device 20 is sometimes called an auxiliary equipment battery. The auxiliary equipment of the work vehicle 2 is, for example, a starter motor, a radiator, etc. The output voltage of the vehicle power storage device 20 is, for example, 24 V.

[0031] The working power storage device 22 can store the electric power generated by the power generation device 14, similar to the vehicle power storage device 20. The working power storage device 22 is electrically connected to the power generation device 14 via the second electric circuit 72. Electric power is supplied from the power generation device 14 to the working power storage device 22 via the second electric circuit 72. This charges the working power storage device 22. The working power storage device 22 is, for example, a lead-acid battery, a nickel-metal hydride battery, or a lithium-ion battery. In this embodiment, of the second electric circuit 72 that connects the working power storage device 22 and the power generation device 14, a portion on the power generation device 14 side merges with the first electric circuit 71. In a modified example, as shown in FIG. 2, a portion on the power generation device 14 side of the second electric circuit 72 may be separated from the first electric circuit 71.

[0032] The amount of stored electricity in the work-use power storage device 22 is detected by a second stored electricity amount sensor 62. Information on the amount of stored electricity in the work-use power storage device 22 detected by the second stored electricity amount sensor 62 is transmitted to the control device 50. The second stored electricity amount sensor 62 is attached to the work-use power storage device 22, for example.

[0033] The second switch 42 and the converter 24 are arranged on the second electric circuit 72 connecting the power generation device 14 and the work-use electric storage device 22. The power generation device 14 and the work-use electric storage device 22 are electrically connected via the second switch 42 and the converter 24. In this embodiment, the second switch 42 is arranged between the power generation device 14 and the converter 24. In a modified example, as shown in FIG. 2, the second switch 42 may be arranged between the converter 24 and the work-use electric storage device 22. The second switch 42 opens and closes the second electric circuit 72 between the power generation device 14 and the work-use electric storage device 22. When the second switch 42 is turned on (closed), the power generation device 14 and the work-use electric storage device 22 are electrically connected via the converter 24, and when the second switch 42 is turned off (open), the power generation device 14 and the work-use electric storage device 22 are electrically disconnected. When the second switch 42 is turned on (closed) while the power generation device 14 and the converter 24 are operating, the electric power generated by the power generation device 14 is charged into the working power storage device 22 via the converter 24.

[0034] The converter 24 can boost the voltage of the power generated by the power generation device 14. The converter 24 is a DC / DC converter that boosts a DC voltage. The converter 24 boosts the DC voltage from 24V to 48V, for example. The converter 24 includes, for example, a plurality of switching elements (not shown), and boosts the DC voltage by turning on / off each of the plurality of switching elements. The low voltage side of the converter 24 is electrically connected to the power generation device 14, and the high voltage side of the converter 24 is electrically connected to the working power storage device 22. The converter 24 boosts the power supplied from the power generation device 14 and supplies it to the working power storage device 22. The power boosted by the converter 24 is charged to the working power storage device 22.

[0035] The work power storage device 22 can supply the stored electric power to the work device 30 via the inverter 26. The work power storage device 22 is electrically connected to the work device 30 via the inverter 26. Electric power discharged from the work power storage device 22 is supplied to the work device 30 via the inverter 26. The output voltage of the work power storage device 22 is, for example, 48 V. The output voltage of the work power storage device 22 is higher than the output voltage of the vehicle power storage device 20.

[0036] The inverter 26 is a device that converts DC power into AC power. The inverter 26 includes, for example, a plurality of switching elements (not shown), and converts DC power into AC power by turning on / off each of the plurality of switching elements. The input side of the inverter 26 is electrically connected to the working power storage device 22, and the output side of the inverter 26 is electrically connected to the motor 32 of the working device 30. The inverter 26 converts the DC power output from the working power storage device 22 into AC power and supplies it to the motor 32 of the working device 30.

[0037] The working device 30 is electrically connected to the working power storage device 22 via the inverter 26. The working device 30 operates by power supplied from the working power storage device 22 via the inverter 26 to perform a predetermined task. The working device 30 performs a task of pumping a fluid (e.g., water), for example. The working device 30 includes, for example, a motor 32 and a pump 34. The motor 32 rotates by power supplied from the working power storage device 22 via the inverter 26. The pump 34 operates by the rotation of the motor 32. The pump 34 includes, for example, an impeller, an intake port, and an exhaust port. The impeller of the pump 34 rotates by the rotation of the motor 32, and the pump 34 draws in a fluid through the intake port by the rotation of the impeller and discharges the drawn liquid from the exhaust port.

[0038] The control device 50 includes, for example, a CPU, a ROM, and a RAM, and executes predetermined control and processing based on a predetermined program. The control device 50 can execute, for example, opening and closing control of the first switch 41 and the second switch 42. The control device 50 can execute, for example, control to switch between a first state in which the first switch 41 is on and the second switch 42 is off, and a second state in which the second switch 42 is on and the first switch 41 is off. The control device 50 also controls, for example, the operations of the engine 12, the converter 24, the inverter 26, and the like. The control and processing executed by the control device 50 will be described later.

[0039] (First process; Figure 3) Next, the first process will be described. The first process is started, for example, when the engine 12 of the work vehicle 2 is started. When the engine 12 is started, the power generator 14 operates by the power of the engine 12 to generate electric power. At the stage when the first process is started, it is assumed that the first switch 41 and the second switch 42 are both off. It is also assumed that the converter 24 is stopped. Note that the work vehicle 2 may be traveling or stopped while the first process is being executed.

[0040] 3, in S10 of the first process, the control device 50 determines whether the amount of stored power in the vehicle power storage device 20 is less than a predetermined first reference amount of stored power (for example, 20 percent of the capacity of the vehicle power storage device 20). The amount of stored power in the vehicle power storage device 20 is detected by a first stored power amount sensor 61. If the amount of stored power in the vehicle power storage device 20 is less than the first reference amount of stored power (YES in S10), the process proceeds to S12. If the amount of stored power in the vehicle power storage device 20 is equal to or greater than the first reference amount of stored power (NO in S10), the process proceeds to S20.

[0041] In S12 after YES in S10, the control device 50 turns on the first switch 41. The second switch 42 is maintained off. That is, the control device 50 switches the first switch 41 and the second switch 42 to a first state in which the first switch 41 is on and the second switch 42 is off. When the first switch 41 is turned on, the electric power generated by the power generation device 14 is supplied to the vehicle power storage device 20 without passing through the converter 24, and the vehicle power storage device 20 is charged.

[0042] In the next step S14, the control device 50 determines whether or not charging of the vehicle power storage device 20 is completed. For example, the control device 50 determines that charging of the vehicle power storage device 20 is completed when the amount of stored electricity in the vehicle power storage device 20 is 98 percent or more of its capacity. If charging of the vehicle power storage device 20 is completed (YES in S14), the process proceeds to S16. If charging of the vehicle power storage device 20 is not completed (NO in S14), the process of S14 continues.

[0043] In S16 after YES in S14, the control device 50 turns off the first switch 41. When the first switch 41 is turned off, the electric power generated by the power generation device 14 is no longer supplied to the vehicle power storage device 20. Then, the process returns to S10.

[0044] In S20 after NO in S10, the control device 50 determines whether the amount of stored power in the work storage device 22 is less than a predetermined second reference amount of stored power (for example, 20 percent of the capacity of the work storage device 22). The amount of stored power in the work storage device 22 is detected by the second amount of stored power sensor 62. If the amount of stored power in the work storage device 22 is less than the second reference amount of stored power (YES in S20), the process proceeds to S22. If the amount of stored power in the work storage device 22 is equal to or greater than the second reference amount of stored power (NO in S20), the process returns to S10.

[0045] In S22 after YES in S20, the control device 50 turns on the second switch 42. The first switch 41 is maintained off. That is, the control device 50 switches the first switch 41 and the second switch 42 to a second state in which the second switch 42 is on and the first switch 41 is off. Also, in S22, the control device 50 starts the converter 24. When the converter 24 starts and the second switch 42 is turned on, the power generated by the power generation device 14 is boosted by the converter 24 and supplied to the work power storage device 22. As a result, the work power storage device 22 is charged.

[0046] In the next step S24, the control device 50 determines whether charging of the work-use power storage device 22 is complete. For example, the control device 50 determines that charging of the work-use power storage device 22 is complete when the amount of stored power in the work-use power storage device 22 is 98 percent or more of its capacity. If charging of the work-use power storage device 22 is complete (YES in S24), the process proceeds to S26. If charging of the work-use power storage device 22 is not complete (NO in S24), the process of S24 continues.

[0047] In S26 after YES in S24, the control device 50 turns off the second switch 42. Also in S26, the control device 50 stops the converter 24. When the second switch 42 is turned off, the power generated by the power generation device 14 is no longer supplied to the work power storage device 22. Thereafter, the process returns to S10. Note that the above-mentioned first process is executed continuously while the engine 12 is operating, for example, and ends when the engine 12 is stopped.

[0048] Although the first embodiment has been described above, the specific embodiment is not limited to the above embodiment. Modifications will be described below. In the following description, detailed descriptions of the same parts as those described above may be omitted.

[0049] (Variation 1 of the first process; Figure 4) In the above embodiment (see FIG. 3), the first process is started, and then the process of S10 is executed, and then the process of S20 is executed, but the present invention is not limited to this configuration. In the first modification, as shown in FIG. 4, the first process is started, and then the process of S20 is executed, and then the process of S10 is executed. That is, the process related to the working power storage device 22 may be executed before the process related to the vehicle power storage device 20.

[0050] (Variation 2 of the first process; FIG. 5) In the second modification, as shown in Fig. 5, after the first process is started, the process of S100 is executed. In S100, the control device 50 judges whether or not the power storage rate of the vehicle power storage device 20 is less than the power storage rate of the work power storage device 22. The power storage rate of the vehicle power storage device 20 is the ratio of the amount of power stored to the capacity of the vehicle power storage device 20. The power storage rate of the work power storage device 22 is the ratio of the amount of power stored to the capacity of the work power storage device 22. If the power storage rate of the vehicle power storage device 20 is less than the power storage rate of the work power storage device 22 (YES in S100), the process proceeds to S10. If the power storage rate of the vehicle power storage device 20 is equal to or greater than the power storage rate of the work power storage device 22 (NO in S100), the process proceeds to S120.

[0051] The processes of S120, S122, S124, and S126 in the second modification are respectively similar to the processes of S20, S22, S24, and S26 in the first process. Also, the processes of S110, S112, S114, and S116 in the second modification are respectively similar to the processes of S10, S12, S14, and S16 in the first process. Therefore, detailed explanations of these processes are omitted.

[0052] (Second treatment; Figure 6) Next, the second process will be described. The second process is started, for example, when the engine 12 of the work vehicle 2 is stopped. When the engine 12 is stopped, the power generation device 14 is stopped and no longer generates electric power. It is assumed that the first switch 41 and the second switch 42 are both off at the stage when the second process is started. It is also assumed that the converter 24 is stopped.

[0053] As shown in FIG. 6, in S30 of the second process, the control device 50 monitors whether the amount of stored power in the vehicle power storage device 20 becomes less than a predetermined first reference amount of stored power (e.g., a storage amount of 20 percent of the capacity of the vehicle power storage device 20). The control device 50 monitors whether the amount of stored power in the vehicle power storage device 20 changes from the first reference amount of stored power or more to less than the first reference amount of stored power. Also, in S30, the control device 50 monitors whether the amount of stored power in the work power storage device 22 becomes less than a predetermined second reference amount of stored power (e.g., a storage amount of 20 percent of the capacity of the work power storage device 22). The control device 50 monitors whether the amount of stored power in the work power storage device 22 changes from the second reference amount of stored power or more to less than the second reference amount of stored power. If the amount of stored power in the vehicle power storage device 20 becomes less than the first reference amount of stored power, or if the amount of stored power in the work power storage device 22 becomes less than the second reference amount of stored power (YES in S30), the process proceeds to S32. If the amount of stored power in the vehicle power storage device 20 does not become less than the first reference amount of stored power, and if the amount of stored power in the work power storage device 22 does not become less than the second reference amount of stored power (NO in S30), the process of S30 continues.

[0054] In S32 after YES in S30, the control device 50 starts the engine 12 of the work vehicle 2. When the engine 12 starts, the power of the engine 12 operates the generator 14 to generate electric power.

[0055] The processes of S10, S12, S14, S16, S20, S22, S24, and S26 after S32 are similar to those of the first process (see FIG. 3). Therefore, detailed explanations of these processes will be omitted. In the second process, the process returns to S10 after S16 or S26. In the second process, if the answer is NO in S20, the process proceeds to S34. In S34, the control device 50 stops the engine 12 of the work vehicle 2. When the engine 12 stops, the power generation device 14 stops and no longer generates electric power.

[0056] (Modification 1 of the second process) In the first modification of the second process, similarly to the first modification of the first process (see FIG. 4), the process related to the working power storage device 22 may be executed before the process related to the vehicle power storage device 20. That is, after S32, the process of S20 may be executed, and thereafter the process of S10 may be executed.

[0057] (Modification 2 of the second process) In the second process variation 2, similarly to the first process variation 2 (see FIG. 5), the process of S100 may be executed. In the second process variation 2, the process of S100 is executed after S32. In S100, the control device 50 determines whether the power storage rate of the vehicle power storage device 20 is less than the power storage rate of the work power storage device 22.

[0058] (Third treatment; Figure 7) Next, the third process will be described. The third process is started, for example, when the engine 12 of the work vehicle 2 is started. When the engine 12 is started, the power of the engine 12 operates the power generator 14 to generate electric power. At the stage when the third process is started, it is assumed that the first switch 41 and the second switch 42 are both off. It is also assumed that the converter 24 is stopped. Note that the work vehicle 2 may be traveling or stopped while the third process is being executed.

[0059] 7, in S40 of the third process, the control device 50 determines whether or not the rotation speed of the engine 12 is less than a predetermined reference rotation speed. The rotation speed of the engine 12 is detected by the rotation speed sensor 64. If the rotation speed of the engine 12 is less than the reference rotation speed (YES in S40), the process proceeds to S10. If the rotation speed of the engine 12 is equal to or greater than the reference rotation speed (NO in S40), the process proceeds to S20.

[0060] The processes of S10, S12, S14, S16, S20, S22, S24, and S26 after S40 are the same as those of the first process (see FIG. 3). Therefore, detailed explanations of these processes will be omitted. In the third process, if NO in S10 or NO in S20, the process returns to S40. The above-mentioned third process is executed continuously while the engine 12 is operating, for example, and ends when the engine 12 stops.

[0061] Example 2 A work vehicle 2 of the second embodiment will be described with reference to the drawings. As shown in Fig. 8, the work vehicle 2 of the second embodiment includes a third electric circuit 73 that electrically connects the vehicle power storage device 20 and the work power storage device 22. The third electric circuit 73 connects the vehicle power storage device 20 and the work power storage device 22 without passing through the power generation device 14. The third electric circuit 73 connects the vehicle power storage device 20 and the work power storage device 22 via the converter 24. The first electric circuit 71 connects the power generation device 14 and the vehicle power storage device 20 without passing through the converter 24. The second electric circuit 72 connects the power generation device 14 and the vehicle power storage device 20 via the converter 24.

[0062] A portion of the third electric circuit 73 on the vehicle power storage device 20 side merges with a portion of the first electric circuit 71 on the vehicle power storage device 20 side. In a modified example, the portion of the third electric circuit 73 on the vehicle power storage device 20 side may be separated from the portion of the first electric circuit 71 on the vehicle power storage device 20 side. In addition, a portion of the third electric circuit 73 on the work power storage device 22 side merges with a portion of the second electric circuit 72 on the work power storage device 22 side. In a modified example, the portion of the third electric circuit 73 on the work power storage device 22 side may be separated from the portion of the second electric circuit 72 on the work power storage device 22 side.

[0063] A third switch 43 and a converter 24 are arranged on a third electric circuit 73 connecting the vehicle power storage device 20 and the work power storage device 22. The vehicle power storage device 20 and the work power storage device 22 are electrically connected via the third switch 43 and the converter 24. The third switch 43 is arranged between the vehicle power storage device 20 and the converter 24. The third switch 43 is arranged on the third electric circuit 73 on the converter 24 side of the junction of the first electric circuit 71 and the third electric circuit 73. The third switch 43 is also arranged on the third electric circuit 73 on the vehicle power storage device 20 side of the junction of the second electric circuit 72 and the third electric circuit 73.

[0064] The first switch 41 is disposed on the first electric circuit 71 closer to the power generator 14 than the junction of the first electric circuit 71 and the third electric circuit 73. The second switch 42 is disposed on the second electric circuit 72 closer to the power generator 14 than the junction of the second electric circuit 72 and the third electric circuit 73.

[0065] The third switch 43 opens and closes a third electric circuit 73 between the vehicle power storage device 20 and the work power storage device 22. When the third switch 43 is turned on (closed), the vehicle power storage device 20 and the work power storage device 22 are electrically connected via the converter 24, and when the third switch 43 is turned off (open), the vehicle power storage device 20 and the work power storage device 22 are electrically disconnected. When the third switch 43 is turned on (closed) while the converter 24 is operating, the power stored in the vehicle power storage device 20 is charged to the work power storage device 22 via the converter 24.

[0066] The converter 24 can boost the electric power stored in the vehicle power storage device 20. The low-voltage side of the converter 24 is electrically connected to the vehicle power storage device 20 via the third switch 43. In addition, the low-voltage side of the converter 24 is electrically connected to the power generation device 14 via the second switch 42. The high-voltage side of the converter 24 is electrically connected to the work power storage device 22. When the third switch 43 is turned on (closed), the converter 24 boosts the electric power stored in the vehicle power storage device 20 and supplies it to the work power storage device 22. In addition, when the second switch 42 is turned on (closed), the converter 24 boosts the electric power generated by the power generation device 14 and supplies it to the work power storage device 22. The electric power boosted by the converter 24 is charged to the work power storage device 22.

[0067] The control device 50 of the second embodiment can execute opening and closing control of the first switch 41, the second switch 42, and the third switch 43. The control device 50 can execute control to switch between, for example, a first state in which the first switch 41 is on and the second switch 42 and the third switch 43 are off, a second state in which the second switch 42 is on and the first switch 41 and the third switch 43 are off, and a third state in which the third switch 43 is on and the first switch 41 and the second switch 42 are off.

[0068] The control device 50 of the second embodiment can execute a first process (see FIG. 3, FIG. 4, FIG. 5), a second process (see FIG. 6), and a third process (see FIG. 7). In the first process, the second process, and the third process, the third switch 43 is maintained off.

[0069] (Fourth treatment; Figure 9) Next, the fourth process will be described. The fourth process is started, for example, when the engine 12 of the work vehicle 2 is stopped. When the engine 12 is stopped, the power generation device 14 is stopped and no longer generates electric power. It is assumed that the first switch 41, the second switch 42, and the third switch 43 are all off at the stage when the fourth process is started. It is also assumed that the converter 24 is stopped.

[0070] As shown in Fig. 9, in S50 of the fourth process, the control device 50 monitors whether the amount of stored power in the work power storage device 22 becomes less than a predetermined third reference amount of stored power (for example, a stored power amount that is 10 percent of the capacity of the work power storage device 22). The control device 50 monitors whether the amount of stored power in the work power storage device 22 changes from equal to or greater than the third reference amount of stored power to less than the third reference amount of stored power. If the amount of stored power in the work power storage device 22 changes to less than the third reference amount of stored power (YES in S50), the process proceeds to S52. If the amount of stored power in the work power storage device 22 does not change to less than the third reference amount of stored power (NO in S50), the process of S50 continues.

[0071] In S52 after YES in S50, the control device 50 determines whether the amount of stored electricity in the vehicle power storage device 20 is equal to or greater than a predetermined fourth reference amount of stored electricity (e.g., 80 percent of the capacity of the vehicle power storage device 20). If the amount of stored electricity in the vehicle power storage device 20 is equal to or greater than the fourth reference amount of stored electricity (YES in S52), the process proceeds to S54. If the amount of stored electricity in the vehicle power storage device 20 is less than the fourth reference amount of stored electricity (NO in S52), the fourth process ends.

[0072] In S54 after YES in S52, the control device 50 turns on the third switch 43. The first switch 41 and the second switch 42 are maintained off. That is, the control device 50 switches the first switch 41, the second switch 42, and the third switch 43 to a third state in which the third switch 43 is on and the first switch 41 and the second switch 42 are off. Also, in S54, the control device 50 starts the converter 24. When the converter 24 starts and the third switch 43 is turned on, the electric power stored in the vehicle power storage device 20 is boosted by the converter 24 and supplied to the working power storage device 22. As a result, the working power storage device 22 is charged.

[0073] In the next S56, the control device 50 monitors whether the amount of stored electricity in the vehicle power storage device 20 becomes less than a predetermined fifth reference amount of stored electricity (for example, an amount of stored electricity that is 20 percent of the capacity of the vehicle power storage device 20). The control device 50 monitors whether the amount of stored electricity in the vehicle power storage device 20 changes from equal to or greater than the fifth reference amount of stored electricity to less than the fifth reference amount of stored electricity. The fifth reference amount of stored electricity is a value less than the fourth reference amount of stored electricity (see S52). If the amount of stored electricity in the vehicle power storage device 20 changes to less than the fifth reference amount of stored electricity (YES in S56), the process proceeds to S58. If the amount of stored electricity in the vehicle power storage device 20 does not change to less than the fifth reference amount of stored electricity (NO in S56), the process of S56 continues.

[0074] In S58 after YES in S56, the control device 50 turns off the third switch 43. Also in S58, the control device 50 stops the converter 24. When the third switch 43 is turned off, power is no longer supplied from the vehicle power storage device 20 to the working power storage device 22. Then, the fourth process ends.

[0075] (Modification of the fourth process) In a modified example of S54 (see FIG. 9), the control device 50 may turn on the third switch 43 and the second switch 42. In a modified example of S58, the control device 50 may turn off the third switch 43 and the second switch 42.

[0076] (effect) As is clear from the above description, in some embodiments, the work vehicle 2 is equipped with a converter 24 that transforms the DC voltage of the electricity generated by the power generation device 14, a work storage device 22 that stores the electricity whose voltage has been transformed by the converter 24, and a work device 30 that operates using power supplied from the work storage device 22 and can perform a specified task.

[0077] According to this configuration, the DC voltage of the electric power generated by the power generation device 14 can be transformed and supplied to the working power storage device 22. This makes it possible to operate the working device 30 without charging the working power storage device 22 by an external device.

[0078] In some embodiments, the work vehicle 2 includes a vehicle power storage device 20 that stores electric power supplied from the power generation device 14 without passing through the converter 24, a first switch 41 that opens and closes a first electric circuit 71 that connects the power generation device 14 and the vehicle power storage device 20, and a second switch 42 that opens and closes a second electric circuit 72 that connects the power generation device 14 and the work power storage device 22 via the converter 24. The control device 50 is capable of executing control to switch between a first state in which the first switch 41 is on and the second switch 42 is off, and a second state in which the second switch 42 is on and the first switch 41 is off. When the first switch 41 is on, electric power generated by the power generation device 14 is supplied to the vehicle power storage device 20 without passing through the converter 24. When the second switch 42 is on, electric power generated by the power generation device 14 is supplied to the work power storage device 22 via the converter 24.

[0079] According to this configuration, by switching between the first state and the second state, it is possible to selectively switch between charging the vehicle power storage device 20 and charging the work power storage device 22.

[0080] In some embodiments, the control device 50 can switch the first switch 41 and the second switch 42 to the first state when the amount of stored electricity in the vehicle power storage device 20 is less than a predetermined first reference amount of stored electricity while the engine 12 is operating (see Figs. 3, 4, 5, 6, and 7). The control device 50 can switch the first switch 41 and the second switch 42 to the second state when the amount of stored electricity in the work power storage device 22 is less than a predetermined second reference amount of stored electricity. With this configuration, the power storage devices 20, 22 can be charged according to the amount of stored electricity in the vehicle power storage device 20 and the work power storage device 22.

[0081] In some embodiments, when the amount of electricity stored in the vehicle power storage device 20 falls below a predetermined first reference amount of electricity or when the amount of electricity stored in the work power storage device 22 falls below a predetermined second reference amount of electricity with the engine 12 stopped, the control device 50 starts the engine 12 (see FIG. 6). According to this configuration, even if the amount of electricity stored in the vehicle power storage device 20 or the work power storage device 22 decreases with the engine 12 stopped, the engine 12 can be started to charge the power storage devices 20, 22 according to the amount of electricity stored in the vehicle power storage device 20 and the work power storage device 22.

[0082] In some embodiments, when the engine 12 is operating and the rotation speed of the engine 12 is less than a predetermined reference rotation speed, the control device 50 can switch the first switch 41 and the second switch 42 to the first state when the amount of stored electricity in the vehicle power storage device 20 is less than a predetermined first reference amount of stored electricity (see FIG. 7). When the engine 12 is operating and the rotation speed of the engine 12 is equal to or greater than the reference rotation speed, the control device 50 can switch the first switch 41 and the second switch 42 to the second state when the amount of stored electricity in the work power storage device 22 is less than a predetermined second reference amount of stored electricity (see FIG. 7). With this configuration, charging to the vehicle power storage device 20 and charging to the work power storage device 22 can be selectively switched depending on the rotation speed of the engine 12.

[0083] In some embodiments, the work vehicle 2 includes a third switch 43 that opens and closes a third electric circuit 73 that connects the vehicle power storage device 20 and the work power storage device 22 via the converter 24. The control device 50 is capable of executing control to switch between a first state in which the first switch 41 is on and the second switch 42 and the third switch 43 are off, a second state in which the second switch 42 is on and the first switch 41 and the third switch 43 are off, and a third state in which the third switch 43 is on and the first switch 41 and the second switch 42 are off. When the third switch 43 is on, the power stored in the vehicle power storage device 20 is transformed by the converter 24 and supplied to the work power storage device 22.

[0084] According to this configuration, by switching between the first state, the second state, and the third state, it is possible to selectively switch between charging from the power generation device 14 to the vehicle power storage device 20, charging from the power generation device 14 to the work power storage device 22, and charging from the vehicle power storage device 20 to the work power storage device 22.

[0085] In some embodiments, when the amount of electricity stored in the work power storage device 22 falls below a predetermined third reference amount of electricity with the engine 12 stopped, and when the amount of electricity stored in the vehicle power storage device 20 is equal to or greater than a predetermined fourth reference amount of electricity, the control device 50 can switch the first switch 41, the second switch 42, and the third switch 43 to the third state. With this configuration, even if the amount of electricity stored in the work power storage device 22 decreases with the engine 12 stopped, if the amount of electricity stored in the vehicle power storage device 20 is sufficient, it is possible to charge the work power storage device 22 with electricity from the vehicle power storage device 20.

[0086] Example 3 A work vehicle 2 of the third embodiment will be described with reference to the drawings. As shown in Fig. 10, the work vehicle 2 of the third embodiment includes a fourth electric circuit 74 that electrically connects the power generation device 14 and the converter 24, a fifth electric circuit 75 that electrically connects the vehicle power storage device 20 and the converter 24, a sixth electric circuit 76 that electrically connects the converter 24 and the inverter 26, and a seventh electric circuit 77 that electrically connects the work power storage device 22 and the inverter 26.

[0087] A portion of the fourth electric circuit 74 on the converter 24 side merges with a portion of the fifth electric circuit 75 on the converter 24 side. In a modified example, the portion of the fourth electric circuit 74 on the converter 24 side may be separated from the portion of the fifth electric circuit 75 on the converter 24 side. A portion of the fifth electric circuit 75 on the vehicle power storage device 20 side merges with a portion of the first electric circuit 71 that connects the power generation device 14 and the vehicle power storage device 20 on the vehicle power storage device 20 side. In a modified example, the portion of the fifth electric circuit 75 on the vehicle power storage device 20 side may be separated from the portion of the first electric circuit 71 on the vehicle power storage device 20 side.

[0088] A fourth switch 44 is disposed on the fourth electric circuit 74, and a fifth switch 45 is disposed on the fifth electric circuit 75. A sixth switch 46 is disposed on the sixth electric circuit 76, and a seventh switch 47 is disposed on the seventh electric circuit 77. The power generation device 14 and the converter 24 are electrically connected via the fourth switch 44, and the vehicle power storage device 20 and the converter 24 are electrically connected via the fifth switch 45. The converter 24 and the inverter 26 are electrically connected via the sixth switch 46, and the work power storage device 22 and the inverter 26 are electrically connected via the seventh switch 47.

[0089] The fourth switch 44 is arranged on the fourth electric circuit 74 closer to the generator 14 than the junction of the fourth electric circuit 74 and the fifth electric circuit 75. The fifth switch 45 is arranged on the fifth electric circuit 75 closer to the vehicle power storage device 20 than the junction of the fourth electric circuit 74 and the fifth electric circuit 75. The fifth switch 45 is also arranged on the fifth electric circuit 75 closer to the converter 24 than the junction of the first electric circuit 71 and the fifth electric circuit 75. The first switch 41 is arranged on the first electric circuit 71 closer to the generator 14 than the junction of the first electric circuit 71 and the fifth electric circuit 75.

[0090] The fourth switch 44 opens and closes a fourth electric circuit 74 between the power generation device 14 and the converter 24. When the fourth switch 44 is turned on (closed), the power generation device 14 and the converter 24 are electrically connected, and when the fourth switch 44 is turned off (open), the power generation device 14 and the converter 24 are electrically disconnected.

[0091] The fifth switch 45 opens and closes a fifth electric circuit 75 between the vehicle power storage device 20 and the converter 24. When the fifth switch 45 is turned on (closed), the vehicle power storage device 20 and the converter 24 are electrically connected, and when the fifth switch 45 is turned off (open), the vehicle power storage device 20 and the converter 24 are electrically disconnected.

[0092] The sixth switch 46 opens and closes a sixth electric path 76 between the converter 24 and the inverter 26. When the sixth switch 46 is turned on (closed), the converter 24 and the inverter 26 are electrically connected, and when the sixth switch 46 is turned off (open), the converter 24 and the inverter 26 are electrically disconnected.

[0093] The seventh switch 47 opens and closes a seventh electric circuit 77 between the work power storage device 22 and the inverter 26. When the seventh switch 47 is turned on (closed), the work power storage device 22 and the inverter 26 are electrically connected, and when the seventh switch 47 is turned off (open), the work power storage device 22 and the inverter 26 are electrically disconnected.

[0094] In the work vehicle 2 of the third embodiment, when the fourth switch 44 and the sixth switch 46 are turned on (closed) while the power generation device 14 and the converter 24 are operating, the electric power generated by the power generation device 14 is supplied to the inverter 26 via the converter 24. It is assumed that the other switches 41, 45, 47 are off.

[0095] Furthermore, when the fifth switch 45 and the sixth switch 46 are turned on (closed) while the converter 24 is operating, the electric power stored in the vehicle power storage device 20 is supplied to the inverter 26 via the converter 24. It is assumed that the other switches 41, 44, and 47 are off.

[0096] Furthermore, when the seventh switch 47 is turned on (closed), the power stored in the work power storage device 22 is supplied to the inverter 26 without passing through the converter 24. It is assumed that the other switches 41, 44, 45, and 46 are off.

[0097] The input side of the inverter 26 is electrically connected to the converter 24 and the working power storage device 22. When the fourth switch 44 and the sixth switch 46 are on (closed), the inverter 26 converts the DC power supplied from the power generation device 14 via the converter 24 into AC power. When the fifth switch 45 and the sixth switch 46 are on (closed), the inverter 26 converts the DC power supplied from the vehicle power storage device 20 via the converter 24 into AC power. When the seventh switch 47 is on (closed), the inverter 26 converts the DC power supplied from the working power storage device 22 into AC power. The power converted into AC power by the inverter 26 is supplied to the motor 32 of the working device 30.

[0098] The working device 30 can perform a predetermined task (for example, pumping water) in a first mode, a second mode, and a third mode. In the first mode, the working device 30 operates on power supplied to the working device 30 from the vehicle power storage device 20 via the converter 24. In the second mode, the working device 30 operates on power supplied to the working device 30 from the work power storage device 22 without passing through the converter 24. In the third mode, the working device 30 operates on power supplied to the working device 30 from the power generation device 14 via the converter 24.

[0099] The control device 50 can execute opening and closing control of the first switch 41, the fourth switch 44, the fifth switch 45, the sixth switch 46, and the seventh switch 47. For example, the control device 50 can execute control to switch these switches 41, 44, 45, 46, and 47 between a fourth state, a fifth state, a sixth state, and a seventh state. The fourth state is a state in which the fourth switch 44 and the sixth switch 46 are on, and the first switch 41, the fifth switch 45, and the seventh switch 47 are off. The fifth state is a state in which the fifth switch 45 and the sixth switch 46 are on, and the first switch 41, the fourth switch 44, and the seventh switch 47 are off. The sixth state is a state in which the first switch 41 is on, and the fourth switch 44 and the fifth switch 45 are off. The seventh state is a state in which the seventh switch 47 is on, and the sixth switch 46 is off. In a modified example, the seventh state may be a state in which the seventh switch 47 is on and the fourth switch 44 and the fifth switch 45 are off.

[0100] (5th treatment; Figure 11) Next, the fifth process will be described. The fifth process is started, for example, when the engine 12 of the work vehicle 2 is stopped. When the engine 12 is stopped, the power generation device 14 is stopped and no longer generates electric power. It is assumed that the first switch 41, the fourth switch 44, the fifth switch 45, the sixth switch 46, and the seventh switch 47 are all off at the stage when the fifth process is started. It is also assumed that the converter 24 is stopped.

[0101] 11, in S60 of the fifth process, the control device 50 monitors whether or not a predetermined start request signal is received from the working device 30. For example, when a predetermined start button (not shown) is pressed on the working device 30, the start request signal is transmitted from the working device 30 to the control device 50. If the control device 50 receives a start request signal from the working device 30 (YES in S60), the process proceeds to S62, and if the control device 50 does not receive a start request signal (NO in S60), the process continues with S60.

[0102] In S62 after YES in S60, the control device 50 turns on the fifth switch 45 and the sixth switch 46. The first switch 41, the fourth switch 44, and the seventh switch 47 are maintained in the OFF state. That is, the control device 50 switches the plurality of switches 41, 44, 45, 46, and 47 to a fifth state in which the fifth switch 45 and the sixth switch 46 are ON and the first switch 41, the fourth switch 44, and the seventh switch 47 are OFF. Also, in S62, the control device 50 starts the converter 24. When the converter 24 starts and the fifth switch 45 and the sixth switch 46 are ON, the electric power stored in the vehicle electric storage device 20 is boosted by the converter 24 and supplied to the inverter 26. When the inverter 26 operates in this state, the working device 30 operates in the first mode. That is, the working device 30 operates by the electric power supplied from the vehicle electric storage device 20 via the converter 24.

[0103] Next, in S64, the control device 50 determines whether a predetermined switching condition is met. The predetermined switching condition is a condition for switching the states of the multiple switches 41, 44, 45, 46, 47 of the work vehicle 2 from the fifth state to the seventh state. The predetermined switching condition is met, for example, when a predetermined time (e.g., 2 seconds) has elapsed since the processing of S62 described above was executed. In a modified example, the predetermined switching condition is met when the voltage input to the inverter 26 after the processing of S62 is executed becomes equal to or greater than a predetermined reference voltage. If the predetermined switching condition is met (YES in S64), the processing proceeds to S66, and if not met (NO in S64), the processing of S64 continues.

[0104] In S66 after YES in S64, the control device 50 turns off the fifth switch 45 and the sixth switch 46. Also, in S66, the control device 50 turns on the seventh switch 47. The first switch 41 and the fourth switch 44 are maintained off. That is, the control device 50 switches the multiple switches 41, 44, 45, 46, and 47 to a seventh state in which the seventh switch 47 is on and the sixth switch 46 is off. The control device 50 switches the states of the multiple switches 41, 44, 45, 46, and 47 from the fifth state to the seventh state. When the seventh switch 47 is turned on, the power stored in the working power storage device 22 is supplied to the inverter 26. When the inverter 26 operates in this state, the working device 30 operates in the second mode. That is, the working device 30 operates by the power supplied from the working power storage device 22 without passing through the converter 24. In addition, in S66, the control device 50 may stop the converter 24.

[0105] In the next step S68, the control device 50 monitors whether or not a predetermined stop request signal is received from the working device 30. For example, when a predetermined stop button (not shown) is pressed on the working device 30, a stop request signal is transmitted from the working device 30 to the control device 50. If the control device 50 receives a stop request signal from the working device 30 (YES in S68), the process proceeds to S70, and if the control device 50 does not receive a stop request signal (NO in S68), the process continues in S68.

[0106] In S70 after YES in S68, the control device 50 turns off the seventh switch 47. When the seventh switch 47 is turned off, power is no longer supplied to the working device 30, and the working device 30 stops. Then, the fifth process ends.

[0107] (effect) As is clear from the above description, the working device 30 of the third embodiment is capable of performing a predetermined task in a first mode in which it operates using power supplied from the vehicle power storage device 20 via the converter 24, and in a second mode in which it operates using power supplied from the work power storage device 22 without passing through the converter 24. When the engine 12 of the work vehicle 2 is stopped and a predetermined start request is obtained from the working device 30, the control device 50 starts the working device 30 in the first mode, and when a predetermined switching condition is met, it switches from the first mode to the second mode and operates the working device 30 in the second mode (see FIG. 10 ).

[0108] According to this configuration, when the working device 30 is started, power is first supplied from the vehicle power storage device 20 to the working device 30, and then power is supplied from the work power storage device 22 to the working device 30, thereby suppressing the occurrence of inrush current in the working device 30.

[0109] (Modification) In the above embodiment, the work vehicle 2 is equipped with a boost converter (converter 24) that boosts the voltage, but is not limited to this configuration. In a modified example, the work vehicle 2 may be equipped with a step-down converter that steps down the voltage, instead of the step-up converter (converter 24). In this case, the output voltage of the work power storage device 22 may be lower than the output voltage of the vehicle power storage device 20.

[0110] There is no particular limitation on the work that can be performed by the working device 30. For example, the working device 30 may be capable of performing lifting work, excavation work, transport work, or the like.

[0111] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0112] 2: work vehicle, 10: vehicle body, 12: engine, 14: power generator, 20: vehicle power storage device, 22: work power storage device, 24: converter, 26: inverter, 30: work device, 41: first switch, 42: second switch, 43: third switch, 44: fourth switch, 45: fifth switch, 46: sixth switch, 47: seventh switch, 50: control device, 61: first power storage amount sensor, 62: second power storage amount sensor, 64: rotation speed sensor, 71: first electric circuit, 72: second electric circuit, 73: third electric circuit, 74: fourth electric circuit, 75: fifth electric circuit, 76: sixth electric circuit, 77: seventh electric circuit

Claims

1. A work vehicle that can run using engine power, a power generation device that is operated by the power of the engine to generate electric power; a converter that transforms a DC voltage of the electric power generated by the power generation device; a work storage device that stores the power whose voltage has been transformed by the converter; a work device that is operable by power supplied from the work power storage device to perform a predetermined task.

2. 2. The work vehicle according to claim 1, a vehicle power storage device that stores electric power supplied from the power generation device without passing through the converter; a first switch that opens and closes an electric path that connects the power generation device and the vehicle power storage device; a second switch that opens and closes an electric path that connects the power generation device and the work-use power storage device via the converter; The work vehicle further includes a control device capable of executing control for switching between a first state in which the first switch is on and the second switch is off, and a second state in which the second switch is on and the first switch is off.

3. A work vehicle according to claim 2, The control device for a work vehicle is capable of switching to the first state when the storage amount of the vehicle power storage device is less than a predetermined first reference storage amount while the engine is operating, and is capable of switching to the second state when the storage amount of the work power storage device is less than a predetermined second reference storage amount.

4. A work vehicle according to claim 2, The control device includes: When the amount of electricity stored in the vehicle power storage device becomes less than a predetermined first reference amount of electricity, or when the amount of electricity stored in the work power storage device becomes less than a predetermined second reference amount of electricity, while the engine is stopped, the engine is started; A work vehicle, wherein when the engine is operating, the vehicle power storage device can be switched to the first state when the amount of stored power in the vehicle power storage device is less than the first reference amount of stored power, and the work vehicle can be switched to the second state when the amount of stored power in the work power storage device is less than the second reference amount of stored power.

5. A work vehicle according to claim 2, The control device, while the engine is operating, when the rotation speed of the engine is lower than a predetermined reference rotation speed and the stored amount of the vehicle power storage device is lower than a predetermined first reference stored amount, the vehicle power storage device is capable of switching to the first state; A work vehicle, wherein when the engine speed is equal to or higher than the reference speed, and the amount of stored electricity in the work-use power storage device is less than a predetermined second reference amount of stored electricity, the work vehicle is switchable to the second state.

6. A work vehicle according to claim 2, a third switch that opens and closes an electric path that connects the vehicle power storage device and the work power storage device via the converter, The control device is capable of executing control to switch between the first state in which the first switch is on and the second switch and the third switch are off, the second state in which the second switch is on and the first switch and the third switch are off, and a third state in which the third switch is on and the first switch and the second switch are off.

7. A work vehicle according to claim 6, The control device for a work vehicle is capable of switching to the third state when the storage amount of the work storage device becomes less than a predetermined third reference storage amount when the engine is stopped, and when the storage amount of the vehicle storage device is equal to or greater than a predetermined fourth reference storage amount.

8. A work vehicle that can run using engine power, a power generation device that is operated by the power of the engine to generate electric power; a vehicle power storage device that stores the electric power generated by the power generation device; A working power storage device having an output voltage different from that of the vehicle power storage device; a work device that is operable by power supplied from the vehicle power storage device or power supplied from the work power storage device to perform a predetermined task; a converter that transforms a DC voltage of the power supplied from the vehicle power storage device to the working device; A control device, the working device is capable of performing the predetermined work in a first mode in which the working device operates using power supplied from the vehicle power storage device via the converter, and in a second mode in which the working device operates using power supplied from the work power storage device without passing through the converter, When the control device acquires a predetermined start request from the working device while the engine is stopped, the control device starts the working device in the first mode, and when a predetermined switching condition is satisfied, the control device switches from the first mode to the second mode and operates the working device in the second mode.

Images