Information display system for electric working vehicle and information display method

Abstract

This information display system for a work vehicle comprises a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, and a second electric motor for driving the PTO shaft. The information display system comprises a meter panel unit, and a control device for controlling the meter panel unit. The control device displays information corresponding to total power consumption of the first electric motor and the second electric motor on the meter panel unit during operation of the work vehicle.

Description

Information display system and information display method for electric work vehicles

[0001] The present invention relates to an information display system and an information display method for electric work vehicles.

[0002] In the field of automobiles, whose primary purpose is to move people or goods, electric vehicles (EVs), which generate the driving force (traction) for propulsion using an electric motor (hereinafter sometimes simply referred to as "motor") instead of an internal combustion engine, are becoming increasingly popular.

[0003] On the other hand, in order to realize a decarbonized society, carbon dioxide (CO2) emitted by work vehicles such as tractors used in fields is being reduced. ２ There is a need to reduce the amount of fuel used. Unlike ordinary automobiles, work vehicles such as tractors need to tow agricultural implements to perform farming tasks such as plowing. Therefore, electrifying work vehicles presents different challenges that need to be addressed compared to electrifying passenger cars.

[0004] Patent Document 1 discloses an electric tractor that distributes and supplies power from a battery to multiple electric motors. The electric tractor comprises a hydraulic pump, a pump motor, a PTO motor, a drive motor, a battery, and an electric drive controller. The pump motor is an electric motor that drives the hydraulic pump. The PTO motor is an electric motor that drives the PTO shaft. The drive motor is an electric motor that drives the vehicle body. The battery supplies power to the pump motor, the PTO motor, and the drive motor. The electric drive controller controls the distribution of power to the pump motor, the PTO motor, and the drive motor.

[0005] Japanese Patent Publication No. 2023-66721

[0006] Electric work vehicles can reduce noise compared to work vehicles driven by internal combustion engines such as diesel engines. However, users sometimes judge the load during work based on the sound of the work vehicle in operation and perform necessary operations, and it is difficult to judge the load based on sound alone with quiet electric work vehicles.

[0007] This invention provides a technology for facilitating the determination of the load during operation in an electric work vehicle.

[0008] This disclosure provides solutions as described in the following items.

[0009] [Item 1] An information display system for a work vehicle comprising a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, and a second electric motor for driving the PTO shaft, comprising a meter panel unit and a control device for controlling the meter panel unit, wherein the control device causes the meter panel unit to display information corresponding to the total power consumption of the first electric motor and the second electric motor while the work vehicle is in operation.

[0010] [Item 2] The information display system according to Item 1, wherein the meter panel unit comprises an analog meter having an indicator needle, and the control device controls the meter panel unit so that the indicator needle moves according to the total power consumption.

[0011] [Item 3] The information display system according to Item 2, wherein the control device controls the meter panel unit to display the ratio of the total power consumption or the magnitude of regenerative power to the sum of the maximum outputs of the first electric motor and the second electric motor using the indicator needle.

[0012] [Item 4] The information display system according to any one of items 1 to 3, wherein the meter panel unit comprises an analog meter having an indicator needle, and an arc-shaped indicator having an arc-shaped light-emitting region located around the movable area of ​​the indicator needle of the analog meter, and the control device controls the meter panel unit so that the color of the light emitted from the light-emitting region changes according to the total power consumption.

[0013] [Item 5] The information display system according to any one of items 1 to 3, wherein the meter panel unit comprises two analog meters, each having an indicator needle, and two arc-shaped indicators, each positioned around the movable area of ​​the indicator needles of the two analog meters, each of the two arc-shaped indicators having an arc-shaped light-emitting area, and the control device controls the meter panel unit such that the color of the light emitted from the light-emitting area of ​​each of the two arc-shaped indicators changes according to the total power consumption.

[0014] [Item 7] The information display system according to Item 5, wherein the meter panel unit further comprises a digital display between the two analog meters, and the control device causes the digital display to show information regarding the total power consumption.

[0015] [Item 8] The control device calculates the ratio of the total power consumption to the sum of the maximum outputs of the first electric motor and the second electric motor, sets the color of the light emitted from the light-emitting region to a first color when the ratio is within a first range, sets the color of the light emitted from the light-emitting region to a second color when the ratio is within a second range, and sets the color of the light emitted from the light-emitting region to a third color when the ratio is within a third range, the information display system according to any one of items 4 to 7.

[0016] [Item 9] A work vehicle comprising: an information display system described in any one of items 1 to 8; the traveling device; the PTO shaft; the first electric motor; and the second electric motor.

[0017] [Item 10] An information display method for a work vehicle comprising a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, a second electric motor for driving the PTO shaft, and a meter panel unit, the information display method comprising: determining the total power consumption of the first electric motor and the second electric motor while the work vehicle is in operation; and displaying information corresponding to the total power consumption on the meter panel unit.

[0018] [Item 11] A computer program for displaying information for a work vehicle comprising a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, a second electric motor for driving the PTO shaft, and a meter panel unit, wherein the computer program causes one or more computers to perform the following actions during the operation of the work vehicle: to determine the total power consumption of the first electric motor and the second electric motor, and to display information corresponding to the total power consumption on the meter panel unit.

[0019] [Item 12] A computer-readable non-temporary storage medium storing a computer program for displaying information for a work vehicle comprising a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, a second electric motor for driving the PTO shaft, and a meter panel unit, wherein the computer program causes one or more computers to perform the following actions during the operation of the work vehicle: to determine the total power consumption of the first electric motor and the second electric motor, and to display information corresponding to the total power consumption on the meter panel unit.

[0020] Comprehensive or specific embodiments of the present invention may be realized by apparatus, systems, methods, integrated circuits, computer programs, or computer-readable non-temporary storage media, or any combination thereof. The computer-readable storage media may include volatile storage media or non-volatile storage media. The apparatus may consist of multiple devices. If the apparatus consists of two or more devices, these two or more devices may be located in a single device or in two or more separate devices.

[0021] According to embodiments of the present invention, it is possible to easily determine the load of travel or work in an electric work vehicle.

[0022] This is a schematic plan view showing an example of the basic configuration of a work vehicle according to an exemplary embodiment of the present invention. This is a side view of a work vehicle according to an exemplary embodiment of the present invention. This is a top view of a work vehicle. This is a block diagram showing an example of the main components of a work vehicle and their connection relationships. This is a block diagram showing an example of the configuration of a power converter and its connection to other equipment. This is a block diagram showing an example of the hardware configuration of each ECU. This is a block diagram showing an example of the configuration of a power distribution unit. This is a schematic front view showing a meter panel unit mounted on a work vehicle. This is a front view showing an example of the arrangement of the main components of the meter panel unit. This is a diagram for explaining the indicator area in the meter panel unit. This is a diagram for explaining an example of the display of a display element in the meter panel unit. This is a block diagram showing an example of the configuration of an information display system. This is a flowchart showing an example of an information display method. This is a block diagram showing an example of a configuration for detecting the total power consumption of the first electric motor and the second electric motor. This is a block diagram showing an example of a configuration for detecting the total output of the first electric motor and the second electric motor. This is the first diagram showing an example in which the color of each arc-shaped indicator changes according to the total power consumption (or total output) of the first electric motor and the second electric motor. The second figure shows an example where the color of each arc-shaped indicator changes according to the total power consumption (or total output) of the first and second electric motors. The third figure shows an example where the color of each arc-shaped indicator changes according to the total power consumption (or total output) of the first and second electric motors.

[0023] Embodiments of the present invention will be described below. However, unnecessarily detailed descriptions may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid the following description becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present invention, and not to limit the subject matter described in the claims. In the following description, components having the same or similar function are denoted by the same reference numerals.

[0024] The following embodiments are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to these embodiments. For example, the numerical values, shapes, materials, steps, and order of steps shown in the following embodiments are merely examples, and various modifications are possible as long as they do not create a technical inconsistency. Furthermore, it is possible to combine one embodiment with other embodiments. The size and positional relationships of the components shown in each drawing may be exaggerated for ease of understanding.

[0025] (Definition of Terms) In this specification, “work vehicle” means a vehicle used for a specific task, such as agricultural work or construction work. “Work” may be, for example, agricultural work, construction work, rubble removal work, or snow removal work. Agricultural work vehicles may be, for example, tractors, combine harvesters, rice transplanters, riding cultivators, vegetable transplanters, vegetable harvesters, lawnmowers, seeders, or fertilizer spreaders. Construction work vehicles may be, for example, backhoes, wheel loaders, or carriers. An agricultural work vehicle such as a tractor or combine harvester, or a construction work vehicle, may function as a “work vehicle” on its own, or the work vehicle and any implements attached to or towed by it may function as a single “work vehicle.” Agricultural work vehicles perform agricultural work on the ground in a field, such as tilling, sowing, pest control, fertilizing, planting crops, or harvesting. Construction work vehicles perform work such as transporting soil, rubble, and other materials at a construction site. These tasks are sometimes referred to as "ground work" or simply "work." The act of a work vehicle moving while performing work is sometimes referred to as "work driving."

[0026] An "electric work vehicle" refers to a work vehicle that runs using an electric motor as its power source. An electric work vehicle may also be equipped with an internal combustion engine as an auxiliary power source in addition to the electric motor. Alternatively, an electric work vehicle may be equipped with an electric motor as an auxiliary power source in addition to the internal combustion engine. An electric work vehicle is equipped with an electrical energy source, such as a battery or fuel cell, to supply power to the electric motor. In the following description, an "electric work vehicle" may be simply referred to as a "work vehicle."

[0027] Electric motors can be synchronous motors such as permanent magnet synchronous motors or reluctance motors, or asynchronous motors such as induction motors.

[0028] A battery is an energy storage device that stores the electrical energy necessary for the operation of electric motors and other electrical components mounted on a work vehicle and / or work machine. A fuel cell is a power generation device that generates such electrical energy from a fuel such as hydrogen. An electrical energy source can be realized by an energy storage device, a power generation device, or a combination of an energy storage device and a power generation device. Furthermore, an electric work vehicle may obtain electrical energy from an electrical energy source located at a distance from the vehicle (e.g., on the ground or on another vehicle) via wired or wireless means.

[0029] When an electric work vehicle performs various "tasks" while moving or stationary, the power required for those tasks may be obtained from electric motors. An electric work vehicle is equipped with one or more electric motors. If an electric work vehicle is equipped with multiple electric motors, certain electric motors may output the driving force required for movement, while other electric motors may output the driving force required for the "tasks." If some or all of the "tasks" are performed by a work machine, the driving force can be mechanically transmitted from one or more electric motors on the electric work vehicle to the work machine. Such mechanical transmission of driving force can be achieved via a power transmission shaft called a power take-off (PTO) shaft.

[0030] The work machine itself may be equipped with an electric motor for the work. In this case, power may be supplied to the electric motor of the work machine from an electrical energy source such as a battery or fuel cell equipped in the electric work vehicle. The work machine may also be equipped with an electrical energy source that stores the power required for the work.

[0031] A "control device" (controller) is a device that controls the operation of part or all of a work vehicle. One example of a "control device" is a computing device comprising at least one processor and at least one memory that stores a computer program (code) that defines the control process executed by the processor. Another example of a "control device" is a computing device with a hardware accelerator such as an FPGA (Field-Programmable Gate Array), ASSP (Application Specific Standard Product), or ASIC (Application-Specific Integrated Circuit) configured or programmed to execute the control process. A control device may also be a collection of multiple devices. For example, several computing devices such as physically separated electronic control units (ECUs) may work together to function as a "control device".

[0032] A "processor" is a hardware electronic circuit such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), ISP (Image Signal Processor), or NPU (Neural Network Processing Unit).

[0033] "Memory" is a hardware electronic circuit such as a ROM (Read Only Memory) or a RAM (Random Access Memory). A part of the memory may be a storage medium connected to the processor via wiring or a network. These hardware electronic circuits can be implemented by one or more integrated circuits (ICs) or large-scale integrated circuits (LSIs). Each functional unit or block within the electronic circuit, and related components, may be manufactured individually as separate integrated circuit chips, or some or all of these functional units or blocks may be combined and manufactured as a single integrated circuit chip. A computer program (hereinafter sometimes simply referred to as a "program") that defines the operation of the processor may be stored in the memory. The program is designed so that the processor executes one or more functions, operations, steps, or processes in the embodiments of the present invention.

[0034] (Embodiment) Hereinafter, several embodiments in which the technology of the present invention is applied to an agricultural electric tractor, which is an example of an electric work vehicle, will be described while referring to the drawings. Various technologies described for the tractor in the following description can also be applied to agricultural machines other than tractors, construction work vehicles used at construction sites, work vehicles used at disaster sites, snow removal vehicles used in heavy snow areas, and vehicles for transporting goods, etc.

[0035] In the following description, the direction of arrow F in the figure is called "front", the direction of arrow B is called "rear", the direction of arrow L is called "left", the direction of arrow R is called "right", the direction of arrow U is called "up", and the direction of arrow D is called "down".

[0036] <1. Basic Configuration of Work Vehicle> FIG. 1 is a plan view schematically showing an example of the basic configuration of a work vehicle 10 according to an exemplary embodiment of the present invention. The illustrated work vehicle 10 is an agricultural electric tractor. The work vehicle 10 can travel in a field while mounting or towing a work implement and performing farm work according to the type of the work implement. The work vehicle 10 can also travel in the field and outside the field (including roads) with the work implement lifted or without mounting the work implement.

[0037] The work vehicle 10 is equipped with a body (vehicle frame) 11 that rotatably supports the left and right front wheels 14F and the left and right rear wheels 14R. The body 11 includes a front frame 12 on which the front wheels 14F are mounted and a transmission case 13 on which the rear wheels 14R are mounted. The front frame 12 is fixed to the front of the transmission case 13. The front wheels 14F and the rear wheels 14R may be collectively referred to as "wheels 14". Strictly speaking, wheels 14 are wheels, and tires are mounted on the wheels 14. In this disclosure, "wheels" generally means the entire "wheel and tire". One or both of the front wheels 14F and the rear wheels 14R may be replaced with a plurality of wheels (crawlers) equipped with a track instead of wheels with tires.

[0038] The work vehicle 10 in the example shown in Figure 1 is equipped with a battery 20 and an electric motor 30 (hereinafter simply referred to as "motor 30") which are directly or indirectly supported by the front frame 12. The battery 20 may be configured as a battery pack including, for example, multiple cells connected in series. The battery 20 is a rechargeable battery that outputs a relatively high voltage, such as a lithium-ion battery or an all-solid-state battery. The battery 20 stores power to drive the motor 30. The battery 20 may be housed in a front housing, for example, called a "bonnet." The front housing is supported by the front frame 12 located at the front of the vehicle body 11.

[0039] Motor 30 is electrically connected to battery 20. Motor 30 can convert the electric power output from battery 20 into mechanical motion (power) and generate the driving force (traction) necessary for the running of work vehicle 10. Motor 30 can be, for example, an AC synchronous motor. Battery 20 generates a direct current. Therefore, when motor 30 is an AC synchronous motor, an electric circuit group including an inverter device (hereinafter sometimes simply referred to as "inverter") may be provided between battery 20 and motor 30. The direct current is converted into an alternating current by the inverter device. A part of such an electric circuit group may be inside battery 20. Also, another part of the electric circuit group may be attached to motor 30 as a drive circuit of motor 30.

[0040] Motor 30 has a rotating output shaft 33. The torque of output shaft 33 is transmitted to rear wheel 14R via mechanical components such as a transmission (speed change device) provided inside transmission case 13 and a rear wheel differential device (differential gear device). In other words, the power generated by motor 30 which is a power source is transmitted to rear wheel 14R by a power transmission system (drive train) 34 including a transmission provided inside transmission case 13. For this reason, the "transmission case" may be called the "mission case". In the four-wheel drive mode, a part of the power of motor 30 is also transmitted to front wheel 14F. Thus, motor 30 drives a running device including a plurality of wheels 14.

[0041] The power of motor 30 may be used not only for the running of work vehicle 10 but also for driving a work implement. A PTO shaft 40 is provided at the rear end of transmission case 13. A work implement can be connected to PTO shaft 40. PTO shaft 40 can be driven by motor 30 that drives the running device or another electric motor not shown in FIG. 1. The torque of output shaft 33 of motor 30 or the output shaft of another motor is transmitted to PTO shaft 40. The work implement mounted on or towed by work vehicle 10 can receive power from PTO shaft 40 and perform operations according to various works. Motor 30 and power transmission system 34 may be collectively referred to as an electric power train.

[0042] As shown in Figure 1, the work vehicle 10 does not have an internal combustion engine such as a diesel engine, but is equipped with a battery 20 and a motor 30. The output shaft 33 of the motor 30 is mechanically coupled to a power transmission system 34, such as a transmission, in a transmission case 13. The motor 30 can efficiently generate torque over a relatively wide range of rotational speeds compared to an internal combustion engine. By using the power transmission system 34, including the transmission, it becomes easy to adjust the torque and rotational speed from the motor 30 over an even wider range by performing multi-stage or continuously variable speed changes. Therefore, it is possible to efficiently perform not only the movement of the work vehicle 10 but also a variety of tasks using work equipment.

[0043] Depending on the intended use or size of the work vehicle 10, some functions of the power transmission system 34 may be omitted. For example, some or all of the transmission responsible for the gear shifting function may be omitted. The number and mounting positions of the motors 30 are not limited to the example shown in Figure 1. Furthermore, the work vehicle may be a hybrid electric vehicle (HEV) equipped with an internal combustion engine such as a diesel engine as a power source in addition to electric motors.

[0044] The work vehicle 10 shown in Figure 1 is equipped with one motor 30. However, the work vehicle 10 may be equipped with multiple electric motors. For example, the work vehicle 10 may be equipped with a drive electric motor that drives a running gear including four wheels 14, and a PTO electric motor that drives the PTO shaft 40. The work vehicle 10 may be equipped with multiple PTO shafts (e.g., a rear PTO shaft, a mid PTO shaft, a front PTO shaft, etc.). In that case, one electric motor may drive multiple PTO shafts, or multiple electric motors may drive multiple PTO shafts. For example, the work vehicle 10 may be equipped with multiple electric motors, each driving a corresponding one of the multiple PTO shafts. The work vehicle 10 may be equipped with a front wheel electric motor that drives two front wheels 14F, and a rear wheel electric motor that drives two rear wheels 14R. Alternatively, the work vehicle 10 may be equipped with two electric motors for the front wheels, each driving one of the two front wheels 14F, and two electric motors for the rear wheels, each driving one of the two rear wheels 14R. In other words, the work vehicle 10 may be equipped with four electric motors, each driving one of the four wheels 14. Thus, the work vehicle 10 may be equipped with one or more electric motors for driving the running gear and one or more electric motors for driving one or more PTO shafts. By providing multiple electric motors, the work vehicle 10 can control the rotation of multiple wheels 14 and one or more PTO shafts more flexibly. In the following description, electric motors for driving may be referred to as "driving motors," and electric motors for PTOs may be referred to as "PTO motors."

[0045] <2. Specific Examples of Work Vehicles> Next, we will explain a more specific example of the configuration of work vehicle 10.

[0046] Figure 2 is a side view of a work vehicle 10 according to an exemplary embodiment of the present invention. Figure 3 is a top view of the work vehicle 10 according to this embodiment.

[0047] The work vehicle 10 shown in Figures 2 and 3 comprises a vehicle body 11 and a running gear supported by the vehicle body 11. The running gear includes various devices necessary for driving, such as left and right front wheels 14F, left and right rear wheels 14R, front axle 15F, rear axle 15R, and a rear wheel differential.

[0048] The vehicle body 11 comprises a front frame 12, a transmission case 13, and a housing frame 16. The front frame 12 is connected to the front of the housing frame 16. The transmission case 13 is connected to the rear of the housing frame 16. A first electric motor 30A and a second electric motor 30B are housed inside the housing frame 16. The first electric motor 30A is a driving motor and drives the running gear via a power transmission system in the transmission case 13. The second electric motor 30B is a PTO motor and drives the PTO shaft 40 and one or more hydraulic pumps. The first electric motor 30A and the second electric motor 30B may be electric motors capable of relatively high efficiency and high torque output, such as permanent magnet synchronous motors.

[0049] The front frame 12 is fitted with a front axle case 17F. The front axle case 17F supports the left and right front wheels 14F. The transmission case 13 includes a rear axle case 17R. The rear axle case 17R supports the left and right rear wheels 14R and transmits power to the rear wheels 14R.

[0050] A battery 20 is mounted on the front frame 12. The battery 20 is supported by the front frame 12 and housed inside the front housing 19 (bonnet). The battery 20 stores the power supplied to the first electric motor 30A and the second electric motor 30B. In other words, the battery 20 stores power for driving, operation, and hydraulic drive. In the following description, the battery 20 may be referred to as the "drive battery 20".

[0051] Above the housing frame 16 and the transmission case 13 are a steering wheel 53, a meter panel unit 54, a group of pedals 55 including the accelerator and brake, a group of switches 56 for work driving, and a driver's seat 52. A safety frame 51 is provided behind the driver's seat 52. The safety frame 51 is attached to the transmission case 13 and has a structure that extends upward. Inside the housing frame 16 are the first electric motor 30A and the second electric motor 30B.

[0052] The switch group 56 includes various operating devices such as switches, levers, and dials for adjusting the operation of the work vehicle 10 and the work implement. The switch group 56 includes various operating devices such as an accelerator lever for adjusting the travel speed, a switch for switching the PTO shaft 40 on and off, a dial for adjusting the rotational speed of the PTO shaft 40, and a lever for adjusting the height of the three-point linkage supporting the work implement. By operating the switch group 56, the driver can give various instructions to the work vehicle 10 for travel and work.

[0053] The meter panel unit 54 displays information regarding the status of the work vehicle 10. For example, the meter panel unit 54 displays various information such as the travel speed, the rotational speed of the PTO shaft 40, the height of the three-point linkage, the output of the motors 30A and 30B, the charge status of the battery 20, and the temperature of the battery 20. The meter panel unit 54 may be equipped with analog meters and / or a digital display (hereinafter simply referred to as "display") for displaying this information. The display of the meter panel unit 54 may display a graphical user interface (GUI) that allows the user to perform various setting operations related to the work vehicle 10. The user can perform various settings related to the work vehicle 10 on the display screen using an input device connected to the meter panel unit 54 or an input means such as a touchscreen mounted on the display.

[0054] As shown in Figure 3, a charging inlet 57 is provided to the right of the steering wheel 53. The charging inlet 57 is a device that includes a socket configured to allow connection of a charging adapter extending from an external power source or charging device. Near the charging inlet 57, a device for the user to initiate charging, such as a charging start button, may be provided. When the user connects the charging adapter to the charging inlet 57 and performs a predetermined operation, such as pressing the charging start button, charging of the battery 20 begins.

[0055] The battery 20 can be charged using either normal charging or rapid charging. In normal charging, AC power supplied from an external AC power source is converted to high-voltage DC power (e.g., around 350V to 450V), and this DC power is supplied to the battery 20. In rapid charging, high-voltage DC power is directly supplied to the battery 20 from an external DC power source. The charging inlet 57 in this embodiment supports both normal and rapid charging. For normal charging, a commercial AC power source that outputs an AC voltage of, for example, 200V or 100V may be used as the power source. For rapid charging, a DC power source that outputs a DC voltage of, for example, around 350V to 450V may be used as the power source. Rapid charging can be performed using protocols compliant with standards such as CHAdeMO, NACS, CCS1, CCS2, GB / T, or ChaoJi.

[0056] The power stored in the battery 20 can also be output to external electrical equipment via the charging inlet 57. Such external power output is referred to as "external power supply" in this specification. External power supply is performed with an external power supply adapter connected to the charging inlet 57. The DC power from the battery 20 can be converted to AC power by a power converter in the work vehicle 10. This AC power can then be supplied to external equipment via the charging inlet 57 and the external power supply adapter.

[0057] As shown in Figure 3, the first electric motor 30A and the second electric motor 30B in this embodiment are arranged side by side. The first electric motor 30A and the second electric motor 30B are rotated by power supplied from the battery 20. The first electric motor 30A drives the running gear via a power transmission system in the transmission case 13. The second electric motor 30B drives the PTO shaft 40 and the hydraulic pump via a power transmission system in the transmission case 13. As a result, the second electric motor 30B drives the work implement and various hydraulic devices. The hydraulic devices may be used, for example, to change the height of the three-point linkage supporting the work implement. The work vehicle 10 may be equipped with a power steering system that assists the driver's steering wheel operation. In this case, the hydraulic devices may also be used in the power steering system to supply auxiliary force to change the steering angle of the front wheels 104F.

[0058] <3. System Configuration of the Work Vehicle> Figure 4 is a block diagram showing the main components of the work vehicle 10 and an example of their connection relationships. In Figure 4, connection relationships related to power transmission, high-voltage drive power, and low-voltage auxiliary power are represented by solid lines of different thicknesses. Connection relationships related to signals (digital signals and analog signals) are represented by dotted lines. Coolant flow is represented by thick dashed lines.

[0059] As shown in Figure 4, the work vehicle 10 is equipped with a first inverter 35A and a second inverter 35B. The first inverter 35A is connected to the first electric motor 30A. The second inverter 35B is connected to the second electric motor 30B. Each of the first inverter 35A and the second inverter 35B converts the DC voltage from the battery 20 into a three-phase AC voltage. The first inverter 35A supplies the converted three-phase AC voltage to the first electric motor 30A. This causes the first electric motor 30A to rotate and the traction device to be driven. The second inverter 35B also supplies the converted three-phase AC voltage to the second electric motor 30B. This causes the second electric motor 30B to rotate and the hydraulic pump 36 and the PTO shaft 40 to be driven.

[0060] The transmission case 13 houses the power transmission system 34A for driving, the power transmission system 34B for work, and the hydraulic pump 36. The power transmission system 34A for driving may include components such as a reduction gear, a sub-transmission, and a differential. The power transmission system 34A for driving transmits power from the rotation of the first electric motor 30A to the rear wheels 14R. In four-wheel drive mode, the power transmission system 34A for driving also transmits a portion of the power from the rotation of the first electric motor 30A to the front wheels 14F. The power transmission system 34B for work may include components such as a reduction gear, a PTO clutch, and a PTO transmission. The power transmission system 34B for work transmits power from the rotation of the second electric motor 30B to the hydraulic pump 36 and the PTO shaft 40. The PTO shaft 40 supplies power for work to the work implement.

[0061] The PTO shaft 40 shown in Figure 4 is the rear PTO shaft. In addition to the rear PTO shaft, the work vehicle 10 may also have a mid-PTO shaft or a front PTO shaft. If the work vehicle 10 has multiple PTO shafts, the power transmission system 34B may be configured to distribute the power generated by the rotation of the second electric motor 30B to the multiple PTO shafts. Alternatively, in addition to the second electric motor 30B that drives the PTO shaft 40, the work vehicle 10 may include other electric motors that drive the other PTO shafts.

[0062] The implements connected to the PTO shaft 40 may include, for example, a rotary tiller, a seeder, a spreader, a transplanter, a mower, a rake, a baler, a harvester, a sprayer, or a harrow. Any implement can be connected to the work vehicle 10 and used.

[0063] The hydraulic pump 36 is driven by power from the second electric motor 30B. The hydraulic pump 36 pressurizes the hydraulic fluid, thereby changing the height of the three-point linkage to which the work equipment is connected. Alternatively, the hydraulic pump 36 may be used in a hydraulic power steering system. If a front loader is mounted as the work equipment, the hydraulic pump 36 may be used in a hydraulic system that enables the lifting and lowering of the front loader. Power from the second electric motor 30B may be transmitted to multiple hydraulic pumps to drive these multiple hydraulic systems. Alternatively, the work vehicle 10 may have one or more electric motors for hydraulics separate from the second electric motor 30B.

[0064] In the example shown in Figure 4, the work vehicle 10 further comprises a power converter 58, a power distribution unit (PDU) 80, an auxiliary battery 21, and a battery temperature control system 70.

[0065] The power converter 58 is positioned between the charging inlet 57 and the battery 20 and performs power conversions such as AC to DC conversion and voltage conversion. Figure 5 shows an example of the configuration of the power converter 58 and its connection to other equipment. The power converter 58 shown in Figure 5 includes an onboard charger (OBC) 81 and a DC-DC converter 82. During normal charging, the OBC 81 converts AC power from the charging inlet 57 to DC power and supplies it to the drive battery 20 via the power distribution unit 80. The drive battery 20 is charged by this DC power. The DC-DC converter 82 is connected to the OBC 81 and also to the battery 20 via the power distribution unit 80. The DC-DC converter 82 converts the relatively high-voltage DC power output from the OBC 81 or the drive battery 20 to lower-voltage DC power (e.g., 12V or 24V). The low-voltage DC power converted by the DC-DC converter 82 is supplied to the auxiliary battery 21 and the auxiliary components 84. The auxiliary components 84 include several devices that operate on the relatively low voltage output from the DC-DC converter 82 or the battery 21. For example, the auxiliary components 84 include several electronic control units (ECUs) and other electrical components. The auxiliary battery 21 is charged by the DC voltage output from the DC-DC converter 82. The auxiliary battery 21 stores the power supplied to the auxiliary components 84, such as each ECU, the meter panel unit 54, the pumps 67, 77, and the air conditioner. The battery 21 may be, for example, a lead-acid battery.

[0066] Refer to Figure 4 again. The work vehicle 10 is equipped with multiple ECUs. The multiple ECUs include a main ECU 61, an electric ECU 62, and a charging ECU 63. The main ECU 61 controls the overall operation of the work vehicle 10 based on signals generated by the user operating the pedal group 55, the switch group 56, and the meter panel unit 54. The electric ECU 62 mainly controls the charging and discharging of the battery 20 and the operation of the electric motors 30A and 30B. The charging ECU 63 communicates with an external charger (external power supply) and performs control to ensure smooth charging by appropriately controlling the relay 64.

[0067] In this embodiment, the combination of the main ECU 61, the electric ECU 62, and the charging ECU 63 functions as a "control device" that controls the operation of the work vehicle 10. Therefore, in the following description, the operations performed by the main ECU 61, the electric ECU 62, and the charging ECU 63 all correspond to operations performed by the "control device". These ECUs can communicate with each other according to a vehicle bus standard such as CAN (Controller Area Network). Instead of CAN, a faster communication method such as on-board Ethernet (registered trademark) may be used. An on-board computer integrating at least some of the functions of the main ECU 61, the electric ECU 62, and the charging ECU 63 may be provided as the "control device". The control device may include ECUs other than the main ECU 61, the electric ECU 62, and the charging ECU 63. Each ECU may be a computing device including one or more processors and one or more memories. Each ECU can perform the operations described later by having the processor execute a computer program stored in the memory.

[0068] The electric ECU 62 sends control signals to the first inverter 35A and the second inverter 35B in response to signals from the pedal group 55 and the switch group 56. The electric ECU 62 can perform motor control based on a rotational speed command value or a torque command value determined, for example, according to the amount of operation of the pedal group 55 by the driver.

[0069] The electric ECU 62 controls the switching operation of multiple switch elements (e.g., MOSFETs) in the first inverter 35A and the second inverter 35B, respectively. Specifically, the electric ECU 62 generates control signals to control the switching operation of each switch element and outputs them to each inverter. The first inverter 35A converts the DC power from the battery 20 into three-phase AC power, which is a pseudo-sine wave of, for example, u-phase, v-phase, and w-phase, according to the control signals from the electric ECU 62, and supplies this three-phase AC power to the first electric motor 30A. Similarly, the second inverter 35B converts the DC power from the battery 20 into three-phase AC power, which is a pseudo-sine wave of, for example, u-phase, v-phase, and w-phase, according to the control signals from the electric ECU 62, and supplies this three-phase AC power to the second electric motor 30B. As a result, the electric ECU 62 can rotate the electric motors 30A and 30B at appropriate rotational speeds and torques according to the driver's operation.

[0070] While the work vehicle 10 is in operation, the main ECU 61 causes the meter panel unit 54 to display information regarding the status of the work vehicle 10. For example, the main ECU 61 displays information such as the travel speed, the operating status of the motors 30A and 30B, the charge status of the battery 20, and the status of the power transmission system 34A and the transmission included in 34A on the meter panel unit 54.

[0071] Figure 6 is a block diagram showing an example of the hardware configuration of each ECU. Each ECU includes a processor 434, ROM 435, RAM 436, external I / F 437, and communication I / F 438. These components are interconnected via a bus 439.

[0072] ROM 435 is, for example, writable memory (e.g., PROM), rewritable memory (e.g., flash memory), or read-only memory. ROM 435 stores a program that controls the operation of the processor 434. ROM 435 does not have to be a single recording medium; it may be a collection of multiple recording media. Some of the multiple storage media may be removable memory.

[0073] RAM 436 provides a working area for temporarily unpacking the program stored in ROM 435 at boot time. RAM 436 does not need to be a single recording medium; it may be a collection of multiple recording media.

[0074] External I / F 437 is an interface for connecting to external devices. Communication I / F 438 is an interface for communicating with other electronic devices (e.g., sensors and other ECUs). For example, communication I / F 438 can perform wired communication compliant with various protocols such as CAN or Ethernet®. Communication I / F 438 may also perform wireless communication compliant with wireless communication standards such as Bluetooth® and / or Wi-Fi®.

[0075] The ECU may further include a storage device for storing data generated by the processor 434 for a relatively long period of time. Such a storage device may be, for example, a semiconductor storage device, a magnetic storage device, or an optical storage device, or a combination thereof.

[0076] The power distribution unit 80 shown in Figure 4 is a device that electrically connects equipment such as the charging inlet 57, power converter 58, battery 20, inverters 35A and 35B, and heater 72.

[0077] Figure 7 shows an example of the configuration of the power distribution unit 80. The power distribution unit 80 may have a plurality of relay circuits 83 (83a to 83g) that operate under the control of the electric ECU 62. During charging, the power distribution unit 80 is configured to supply power from the charging inlet 57 or the power converter 58 to the battery 20, and to the heater 72 when the temperature is low. On the other hand, during discharging, the power distribution unit 80 is configured to distribute power from the battery 20 to the first inverter 35A, the second inverter 35B, and the power converter 23. The electric ECU 62 may be configured or programmed to control the charging and discharging of the battery 20 by appropriately switching the on and off of the plurality of relay circuits 83a to 83g in the power distribution unit 80. In this specification, relay circuits may be simply referred to as "relays".

[0078] As shown in Figure 4, the battery 20 includes a battery management system (BMS) 22 and a temperature sensor 24. The BMS 22 is configured to monitor the state of the battery 20, such as the input voltage, output voltage, and temperature, and to control the charging and discharging currents to the battery 20 based on these states. The temperature sensor 24 may be configured to measure the temperature of each of the multiple cells contained in the battery 20.

[0079] The work vehicle 10 illustrated in Figure 4 is equipped with a cooling system 60 for high-voltage equipment and a battery temperature control system 70. The cooling system 60 is used to cool equipment to which high voltage is applied (also referred to as "high-voltage equipment"). The cooling system 60 comprises a radiator 65, a reservoir tank 66, a pump 67, and a cooling fan 68. In the example in Figure 4, the cooling system 60 is connected via hoses to the first inverter 35A, the first electric motor 30A, the second electric motor 30B, the second inverter 35B, and the power converter 58 in that order. This forms a flow path through which the coolant circulates. The coolant in the cooling system 60 is, for example, water or oil. The cooling system 60 cools these high-voltage equipment by circulating the coolant through the flow path. The coolant heated by the high-voltage equipment is cooled by heat dissipation in the radiator 65. The cooling fan 68 generates cooling air to cool the coolant inside the radiator 65. The cooling air promotes heat dissipation from the radiator 65.

[0080] The battery temperature control system 70 is used to cool or heat (also referred to as "heating") the battery 20. The battery temperature control system 70 comprises a heater 72, a radiator 75, a reservoir tank 76, and a pump 77. The battery temperature control system 70 is connected to the battery 20 via a hose. This creates a passage through which the coolant circulates. The coolant in the battery temperature control system 70 is, for example, water or oil. The battery temperature control system 70 cools the battery 20 by circulating the coolant through the passage. The coolant heated by the battery 20 is cooled by heat dissipation in the radiator 75. Cooling air from the cooling fan 68 also plays a role in cooling the coolant inside the radiator 75. The heater 72 raises the temperature of the battery 20 by warming the coolant. This makes it possible to suppress a decrease in the charge and discharge performance of the battery 20 even in low-temperature environments where the ambient temperature is, for example, below 0 degrees Celsius (°C).

[0081] The operation of the cooling system 60 and the battery temperature control system 70 is controlled by the electric ECU 62. For example, the electric ECU 62 is configured or programmed to maintain the temperature of the battery 20 within an appropriate range by controlling the battery temperature control system 70 based on the temperature of the battery 20 measured by the temperature sensor 24. In addition to the measurement value of the temperature sensor 24, the electric ECU 62 may also control the battery temperature control system 70 based on the measurement value of a temperature sensor 25 that measures the ambient temperature and is installed in the work vehicle 10.

[0082] The flow paths of the coolant in the cooling system 60 and the battery temperature control system 70 are not limited to the illustrated paths and can be changed as appropriate. The cooling method in the cooling system 60 and the battery temperature control system 70 is not limited to water cooling or oil cooling, but may also be air cooling. Alternatively, the refrigerant used in an air conditioner may be used instead of the above-mentioned coolant.

[0083] <4. Example of Meter Panel Unit Configuration> Figure 8 is a schematic front view showing a meter panel unit 54 attached to a work vehicle 10. In the illustrated example, the meter panel unit 54 is positioned on the front side of the driver's seat of the work vehicle 10. Specifically, the meter panel unit 54 is fitted into an opening in the meter cover 240 above the handle stay 230 that rotatably supports the steering wheel 220 (handle). The meter panel unit 54 is positioned so that it can be seen by the driver seated in the driver's seat.

[0084] Figure 9 is a front view showing an example of the arrangement of the main components of a meter panel unit 54. The meter panel unit 54 shown in Figure 9 includes a meter section 110. The meter section 110 has a first analog meter 111, a second analog meter 112, and a display element 113. The display element 113 is positioned between the first analog meter 111 and the second analog meter 112.

[0085] The first analog meter 111 has an indicator needle 102A. The second analog meter 112 has indicator needles 102B and 102C. Indicator needle 102A is rotatably supported around a pivot axis located near the center of the first analog meter 111. Depending on the direction in which the tip of indicator needle 102A points, it indicates, for example, the total power consumption or total output of the first electric motor 30A and the second electric motor 30B. Indicator needles 102B and 102C are rotatably supported around two pivot axes located at different locations on the second analog meter 112. Depending on the direction in which the tip of indicator needle 102B points, it indicates, for example, the battery level. Indicator needle 102C indicates, for example, the battery temperature, depending on the direction in which the tip of indicator needle 102C points. The indicator needles 102A, 102B, and 102C are driven by the drive unit (movement) provided in the meter unit 110. The drive unit receives electrical signals indicating sensor outputs such as the power consumption of the first electric motor 30A and the second electric motor 30B, the battery level, or the battery temperature, and can convert these into mechanical motion that changes the direction of the indicator needles 102A, 102B, and 102C. Each of the drive units for the indicator needles 102A, 102B, and 102C has an actuator such as a stepping motor.

[0086] The first analog meter 111 further comprises a first arc-shaped indicator 140A. The second analog meter 112 further comprises a second arc-shaped indicator 140B. The first arc-shaped indicator 140A is positioned around the movable area of ​​the indicator needle 102A. The second arc-shaped indicator 140B is positioned around the movable areas of the indicator needles 102B and 102C. In this disclosure, "arc" means a part of a circle (circumference), but this circle is not limited to a "perfect circle" and may include a part where the curvature changes gradually or locally, such as a part of an ellipse. The first arc-shaped indicator 140A and the second arc-shaped indicator 140B have a symmetrical structure.

[0087] Each of the arc-shaped indicators 140A and 140B may include multiple light-emitting elements (e.g., LEDs) that emit light of different colors. These multiple light-emitting elements may include, for example, LEDs that emit red light, LEDs that emit green light, and LEDs that emit blue light. By selectively emitting these LEDs, the arc-shaped indicators 140A and 140B can perform the function of notifying the operator of information using light of various colors. For this reason, the arc-shaped indicators 140A and 140B are sometimes referred to as "communication rings."

[0088] The display element 113 is a digital meter (i.e., a digital display), not an analog meter. The display element 113 is, for example, an active-matrix display such as a liquid crystal display panel or an OLED (Organic Light Emitting Diode). The display element 113 has a large number of pixels arranged two-dimensionally in a display area, and a display visible to the human eye is realized by the light emitted from the large number of pixels. In the display element 113 in this embodiment, each pixel includes RGB subpixels, and a color image can be displayed. The display element 113 can display numbers, characters, figures, icons, symbols, still images, or moving images of any size at any position within the display area. Strictly speaking, numbers, characters, figures, icons, and symbols are also part of the image (still image or moving image) that the display element 113 displays in the display area. The display element 113 can also display an image that, for example, superficially resembles all or part of an analog meter with an indicator needle. When the display element 113 displays an image of an "analog meter," it is possible to rotate the "indicator needle" within the image to any direction as part of a video by changing the image frame by frame.

[0089] The difference between the image of the "analog meter" displayed by a digital display such as the display element 113 and the first analog meter 111 and the second analog meter 112 is that the former is two-dimensional, while the latter is three-dimensional. Furthermore, the former allows for changes in the shape, color, and size of the indicator needle and scale of the analog meter, whereas it is difficult to change these in the latter. In addition, the visibility of the former depends on the contrast of the image, so visibility may decrease when exposed to strong sunlight during the day, whereas this possibility is relatively small in the latter. Taking these factors into consideration, in this embodiment, some of the information displayed on the meter unit 110, especially information of high importance that requires strong visibility, is displayed by an analog meter with a three-dimensional structure.

[0090] When viewed from the front, the meter section 110 has an outline that resembles an ellipse, but the outline of the meter section 110 is not limited to this example. When viewed from the front, the outline of the meter section 110 may be roughly a rectangle, or it may be a figure that combines straight lines and curves.

[0091] Next, the indicator area of ​​the meter unit 110 will be described with reference to Figure 10. In the example of Figure 10, the meter unit 110 has an indicator area 114T provided above the display element 113, and indicator areas 114L and 114R provided below the display element 113. Various indicators are provided in each of the indicator areas 114T, 114L, and 114R. When the light-emitting element behind each indicator, such as an LED, is lit, it displays predetermined information such as a warning.

[0092] In this embodiment, two indicator areas 114L and 114R, which are divided into left and right sections, are arranged at the bottom of the display element 113. However, a single indicator area formed by integrating the two indicator areas may also be arranged.

[0093] In the indicator area 114T located above the display element 113, indicators that show particularly important information (information with a high warning level) may be selected and placed from among a number of indicators (for example, indicators that show the illumination status of lighting devices, turn signals, warnings to the driver, etc.). The "warning level" of the information displayed by the indicators may be defined, for example, in the owner's manual for the work vehicle. For example, information such as motor abnormality or failure, or whether the headlights are illuminated, has a high warning level.

[0094] In this embodiment, each indicator located in the indicator areas 114T, 114L, and 114R consists of a translucent area shaped to define a characteristic figure (including icons and / or characters) and a light-emitting element located behind it. The indicators can be turned on or off by turning the light-emitting element behind them on or off. Behind each indicator, for example, one or two light-emitting elements are located.

[0095] Next, an example of the display of the display element 113 will be described with reference to Figure 11. In the example in Figure 11, the display area of ​​the display element 113 is divided into several areas. Each area displays an "image" showing information such as the gear shift stage, vehicle speed, various function performance displays, and hour meter. This image contains various types of information represented by letters, numbers, shapes, icons, symbols, etc. Diverse digital images may be shown in different colors to enhance visibility. Furthermore, when it is particularly important to attract the operator's attention, the position, size, or color of at least one of the letters, numbers, shapes, icons, or symbols may be changed to provide a highlighted display. When such a highlighted display is performed, sound or voice may be emitted from an audio device such as a speaker.

[0096] <5. Information Display System> Next, an example of the configuration of an information display system mounted on the work vehicle 10 will be described. Figure 12 is a schematic block diagram showing an example of the configuration of the information display system 500. The information display system 500 shown in Figure 12 comprises the meter panel unit 54 described above and a control device 400 that controls the meter panel unit 54. The control device 400 includes the main ECU 61 and the electric ECU 62 shown in Figure 4. The control device 400 is communicated via a bus 650 to the sensor group 620 provided on the work vehicle 10. The control device 400 receives sensor data output from multiple sensors included in the sensor group 620 and controls the display of the meter panel unit 54 according to the state of the work vehicle 10.

[0097] In this embodiment, the control device 400 displays information on the meter panel unit 54 corresponding to the total power consumption of the first electric motor 30A and the second electric motor 30B while the work vehicle 10 is in operation. Here, "total power consumption" is the sum of the power consumption of the first electric motor 30A and the power consumption of the second electric motor 30B. The meter panel unit 54 may display the value of the total power consumption of the first electric motor 30A and the second electric motor 30B itself as "information corresponding to total power consumption," or it may display other quantities that change according to the total power consumption. For example, it may output the sum of the output of the first electric motor 30A and the output of the second electric motor 30B (hereinafter also referred to as "total output"). The motor output is expressed as the product of the motor's rotational angular velocity ω (rad / s) and torque T (N・m), and corresponds to the value obtained by subtracting losses from the power consumption (input power).

[0098] Figure 13 is a flowchart showing an example of an information display method performed by the control device 400. In the example shown in Figure 13, the control device 400 obtains measured values ​​of the input voltage and input current of the first electric motor 30A and the second electric motor 30B from the sensor group 620 (step S101). Next, the control device 400 calculates the input power, i.e., power consumption, of the first electric motor 30A and the second electric motor 30B based on these measured values ​​(step S102). The control device 400 calculates the total power consumption of the first electric motor 30A and the second electric motor 30B by adding their power consumptions (step S103). The control device 400 displays information corresponding to the calculated total power consumption on the meter panel unit 54 (step S104). The operations from steps S101 to S104 are repeated while the work vehicle 10 is in operation. This operation effectively communicates the degree of the workload performed by the work vehicle 10 to the user.

[0099] Information corresponding to the total power consumption of the first electric motor 30A and the second electric motor 30B can be displayed by an indicator needle 102A on an analog meter 111, as shown in Figures 9 to 11. In this example, the control device 400 controls the meter panel unit 54 so that the indicator needle 102A on the analog meter 111 moves according to the total power consumption of the first electric motor 30A and the second electric motor 30B. For example, the control device 400 may be configured to control the meter panel unit 54 so that the indicator needle 102A displays the ratio of the current total power consumption (or total output) to the upper limit of the total power consumption (or total output) of the first electric motor 30A and the second electric motor 30B, or the magnitude of the regenerative power. In the example shown in Figures 9 to 11, the current total power consumption (or total output) of the first electric motor 30A and the second electric motor 30B is displayed by the indicator needle 102A pointing to a gauge portion 132 labeled "PWR". On the other hand, regenerative power is indicated by the indicator needle 102A pointing to the gauge section 134, which is marked with the letters "CHG".

[0100] In this embodiment, the electric work vehicle generates less noise compared to work vehicles driven by internal combustion engines such as diesel engines. Therefore, it is not easy for the user to judge the load during work driving based on the level of noise. To address this, in this embodiment, the control device 400 is configured to display information on the meter panel unit 54 corresponding to the total power consumption (or total output) or regenerative power of the first electric motor 30A for driving and the second electric motor 30B for the PTO. This effectively communicates the degree of load during driving or work, or the amount of regeneration, to the user. In particular, by using an analog meter 111 with an indicator needle 102A as shown in Figure 9, the degree of load and the amount of regeneration during work driving can be easily communicated to the user.

[0101] The control device 400 may also display information corresponding to the power consumption of the first electric motor 30A and information corresponding to the power consumption of the second electric motor 30B separately in different areas of the meter panel unit 54. For example, this information may be displayed separately by the two indicator needles 102B and 102C of the analog meter 112 shown in Figure 9. In this case, the total power consumption of motors 30A and 30B does not need to be displayed. The control device 400 may also display information regarding the individual power consumption of motors 30A and 30B, or the total power consumption of motors 30A and 30B, on a display element 113 (i.e., a digital display) instead of the analog meters 111 and 112. For example, the individual power consumption of motors 30A and 30B, or information corresponding to their total power consumption, may be displayed on the display element 113 by an image that mimics an analog meter or an image of a gauge. Numerical values ​​corresponding to the individual power consumption of motors 30A and 30B, or their total power consumption, may be displayed on the display element 113.

[0102] The control device 400 can detect the power consumption or output of the first electric motor 30A and the second electric motor 30B, respectively, based on signals output from multiple sensors included in the sensor group 620 shown in Figure 12. An example of the detection method will be described below.

[0103] Figure 14A is a block diagram showing a part of the configuration shown in FIG. 4 in more detail. In the example shown in FIG. 14A, the first inverter 35A and the second inverter 35B each include sensors 31A and 31B. The sensors 31A and 31B are included in the sensor group 620 shown in FIG. 12. The sensor 31A measures the voltage and current input from the first inverter 35A to the first electric motor 30A, and transmits a signal indicating the measured values to the electric ECU 62 included in the control device 400. The sensor 31B measures the voltage and current input from the second inverter 35B to the second electric motor 30B, and sends a signal indicating the measured values to the electric ECU 62. These signals are transmitted by communication such as CAN, for example. The electric ECU 62 calculates the total power consumption of the first electric motor 30A and the second electric motor 30B based on the signals output from the sensors 31A and 31B. The main ECU 61 causes the meter panel unit 54 to display information corresponding to the total power consumption.

[0104] Here, let the measured values of the voltage and current input to the first electric motor 30A be V １ , I １ , respectively, and let the measured values of the voltage and current input to the second electric motor 30B be V ２ , I ２ , respectively. The electric ECU 62 may be configured to calculate the ratio P of the total power consumption to the total maximum power consumption P ｍａｘ of the first electric motor 30A and the second electric motor 30B based on, for example, the following equation (1). P(%) = { (V １ · I １ ) + (V ２ · I ２ )} / P ｍａｘ (1) Pmax is a value determined by the specifications of the first electric motor 30A and the second electric motor 30B, and is pre-recorded in the memory of the electric ECU 62. The main ECU 61 may be configured to display the calculated ratio P as information corresponding to the total power consumption of the first electric motor 30A and the second electric motor 30B on the meter panel unit 54.

[0105] In this embodiment, the above operations are performed by the electric ECU 62 and the main ECU 61, but the above operations may be performed by one or more ECUs or other computers. Thus, the control device 400 can be implemented by one or more computers.

[0106] Sensors 31A and 31B may be provided outside inverters 35A and 35B, respectively. That is, sensor 31A may be provided between inverter 35A and motor 30A, and sensor 31B may be provided between inverter 35B and motor 30B. Also, each of sensors 31A and 31B may calculate power based on the measured voltage and current and transmit the value of said power to the motor ECU 62. In that case, the motor ECU 62 will use the power value obtained from sensors 31A and 31B (V in equation (1) above) １ I １ and V ２ I ２ It may be configured to calculate the percentage P of total power consumption based on (equivalent to)

[0107] Instead of sensors 31A and 31B, sensors 32A and 32B may be provided to measure the output (or torque and rotational speed) of motors 30A and 30B, as shown in Figure 14B. The control device 400 may calculate the total output of motors 30A and 30B based on the signals output from sensors 32A and 32B and display the value of the total output on the meter panel unit 54.

[0108] The meter panel unit 54 shown in Figure 9 includes a first arc-shaped indicator 140A located around the movable area of ​​the indicator needle 102A of the first analog meter 111, and a second arc-shaped indicator 140B located around the movable area of ​​the indicator needle 102B of the second analog meter 112. Each of the first arc-shaped indicator 140A and the second arc-shaped indicator 140B has an arc-shaped light-emitting area. The control device 400 may control the meter panel unit 54 so that the color of the light emitted from one or both of the light-emitting areas of the first arc-shaped indicator 140A and the second arc-shaped indicator 140B changes according to the total power consumption of the first electric motor 30A and the second electric motor 30B. Such control makes it easier for the user to understand that the work vehicle 10 is in a high-load state. A specific example of such a display will be described below.

[0109] Figures 15A, 15B, and 15C show an example in which the colors of the arc-shaped indicators 140A and 140B change according to the total power consumption (or total output) of the first electric motor 30A and the second electric motor 30B. In this example, the control device 400 calculates the sum of the maximum outputs P of the first electric motor 30A and the second electric motor 30B based on the above equation (1). ｍａｘ The control device 400 calculates the ratio P (%) of total power consumption to the total power consumption. As shown in Figure 15A, when the ratio P is in a first range (e.g., -100% or more and less than 0%: during regeneration), the control device 400 sets the color of the light emitted from the respective light-emitting regions of the arc-shaped indicators 140A and 140B to a first color (e.g., green). As shown in Figure 15B, when the ratio P is in a second range greater than the first range (e.g., 0% or more and less than 90%: during normal operation), the control device 400 sets the color of the light emitted from the respective light-emitting regions of the arc-shaped indicators 140A and 140B to a second color different from the first color (e.g., blue). As shown in Figure 15C, when the ratio P is in a third range greater than the second range (for example, 90% to 100%: under high load), the control device 400 changes the color of the light emitted from the respective light-emitting regions of the arc-shaped indicators 140A and 140B to a third color different from the first and second colors (for example, purple).

[0110] Thus, the control device 400 may change the color of the light emitted from the light-emitting areas of the arc-shaped indicators 140A and 140B according to the total power consumption of the motors 30A and 30B. This allows the user to recognize the magnitude of the load during driving or work, or whether regenerative braking is in progress, without having to look at the meter panel unit 54.

[0111] In the example shown in Figures 15A to 15C, the color of the light emitted from the light-emitting elements of the left and right arc-shaped indicators 140A and 140B is changed to the same color, but the colors of the two may be different. Also, the number of arc-shaped indicators whose color is changed may be just one (for example, only arc-shaped indicator 140A). Instead of changing the color, the blinking pattern of the arc-shaped indicator may be changed according to the total power consumption of motors 30A and 30B.

[0112] In the embodiments described above, the control device 400 expresses fluctuations in the load during operation by moving the indicator needle 102A of the analog meter 111 or changing the color of the arc-shaped indicators 140A and 140B according to the total power consumption of the motors 30A and 30B. However, the disclosure is not limited to such forms. For example, instead of the analog meters 111 and 112 and the arc-shaped indicators 140A and 140B, the display element 111 may display information corresponding to the total power consumption of the motors 30A and 30B. In that case, the meter panel unit 54 does not need to be equipped with the analog meters 111 and 112 and the arc-shaped indicators 140A and 140B.

[0113] As described above, the control device 400 in this embodiment expresses the magnitude of the load during work driving through visual information from the meter panel unit 54. In addition to this, or instead, the control device 400 may express the magnitude of the load through sound information from an acoustic device such as a speaker. For example, the control device 400 may generate a simulated engine sound, similar to that emitted by a conventional engine vehicle, using an acoustic device, and change the volume of the sound to increase in accordance with the increase in the total power consumption (or total output) of the motors 30A and 30B. With such a method, just like with a conventional engine vehicle, the user can easily determine the magnitude of the load during work driving of the work vehicle 10 based on the sound.

[0114] In the example shown in Figure 4, two electric motors 30A and 30B are provided on the work vehicle 10, but as shown in Figure 1, the work vehicle 10 may have a single electric motor 30. In that case, the control device 400 may display information on the meter panel unit 54 according to the power consumption or output of the electric motor 30. For example, the control device 400 may move the indicator needle of one or more analog meters on the meter panel unit 54 or change the light emission color or light emission pattern of one or more arc-shaped indicators according to the power consumption or output of the electric motor 30.

[0115] The information display systems in the above embodiments can also be retrofitted to work vehicles that do not have this function. Such systems can be manufactured and sold independently of the work vehicles. Computer programs used in such systems can also be manufactured and sold independently of the work vehicles. Computer programs can be provided, for example, stored in a computer-readable non-temporary storage medium. Computer programs can also be provided by download via telecommunications lines (e.g., the Internet).

[0116] The present invention can be applied to agricultural tractors equipped with electric motors for driving, and to electric work vehicles such as construction vehicles.

[0117] 10...Work vehicle, 11...Body, 12...Front frame, 13...Transmission case, 14...Wheels, 14F...Front wheels, 14R...Rear wheels, 15F...Front axle, 15R...Rear axle, 16...Housing frame, 17F...Front axle case, 17R...Rear axle case, 19...Front housing, 20...Battery, 22...Battery management system (BMS), 24...Temperature sensor, 30, 30A, 30B...Electric motor, 33...Output shaft, 34...Power transmission system, 35A, 35B...Inverter, 36...Hydraulic pump, 40...PTO shaft, 51...Loops frame, 52...Driver's seat, 53...Steering wheel, 54...Meter panel unit, 55...Pedal group, 56...Switch group, 57...Charging inlet, 58...Power converter, 60... High-voltage equipment cooling system, 61... Main ECU, 62... Electric ECU, 63... Charging ECU, 64... Relay, 65... High-voltage equipment radiator, 66... ​​Reservoir tank, 67... Pump, 68... Cooling fan, 70... Battery temperature control system, 72... Heater, 75... Battery radiator, 76... Reservoir tank, 77... Pump, 80... Power distribution unit, 81... Onboard charger (OBC), 82... DC-DC converter, 102A, 102B, 102C... Indicator needle, 110... Meter section, 111... First analog meter, 112... Second analog meter, 113... Display element, 140A, 140B... Arc-shaped indicator, 500... Information display system, 400... Control device, 620... Sensor group

Claims

1. An information display system for a work vehicle comprising a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, and a second electric motor for driving the PTO shaft, the system comprising a meter panel unit and a control device for controlling the meter panel unit, wherein the control device causes the meter panel unit to display information corresponding to the total power consumption of the first electric motor and the second electric motor while the work vehicle is in operation.

2. The information display system according to claim 1, wherein the meter panel unit comprises an analog meter having an indicator needle, and the control device controls the meter panel unit so that the indicator needle moves according to the total power consumption.

3. The information display system according to claim 2, wherein the control device controls the meter panel unit to display the ratio of the total power consumption of the first electric motor and the second electric motor to the upper limit of the total power consumption, or the magnitude of the regenerative power, on the indicator needle.

4. The information display system according to claim 1, wherein the meter panel unit comprises an analog meter having an indicator needle, and an arc-shaped indicator having an arc-shaped light-emitting region located around the movable area of ​​the indicator needle of the analog meter, and the control device controls the meter panel unit so that the color of the light emitted from the light-emitting region changes according to the total power consumption.

5. The information display system according to claim 1, wherein the meter panel unit comprises two analog meters, each having an indicator needle, and two arc-shaped indicators, each positioned around the movable area of ​​the indicator needles of the two analog meters, each of the two arc-shaped indicators having an arc-shaped light-emitting area, and the control device controls the meter panel unit such that the color of the light emitted from the light-emitting area of ​​each of the two arc-shaped indicators changes according to the total power consumption.

6. The information display system according to claim 5, wherein the meter panel unit further comprises a digital display between the two analog meters, and the control device causes the digital display to display information regarding the total power consumption.

7. The control device calculates the ratio of the total power consumption to the sum of the maximum outputs of the first electric motor and the second electric motor; when the ratio is within a first range, the color of the light emitted from the light-emitting region is set to a first color; when the ratio is within a second range, the color of the light emitted from the light-emitting region is set to a second color; and when the ratio is within a third range, the color of the light emitted from the light-emitting region is set to a third color, according to any one of claims 4 to 6.

8. A work vehicle comprising: an information display system according to any one of claims 1 to 6; the traveling device; the PTO shaft; the first electric motor; and the second electric motor.

9. An information display method for a work vehicle comprising a traveling device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the traveling device, a second electric motor for driving the PTO shaft, and a meter panel unit, the information display method comprising: determining the total power consumption of the first electric motor and the second electric motor while the work vehicle is in operation; and displaying information corresponding to the total power consumption on the meter panel unit.

10. A computer program for displaying information for a work vehicle comprising a travel device, a PTO shaft for supplying power to a work machine, a first electric motor for driving the travel device, a second electric motor for driving the PTO shaft, and a meter panel unit, wherein the computer program causes one or more computers to perform the following actions during the operation of the work vehicle: to determine the total power consumption of the first electric motor and the second electric motor, and to display information corresponding to the total power consumption on the meter panel unit.

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