Electric vehicle power efficiency calculation system, driving range calculation system, program and method

Abstract

This makes it possible to calculate power efficiency taking into account the ability to follow the driving environment and stability. [Solution] The power efficiency calculation system 50 includes a section power efficiency acquisition unit 51 that acquires the section power efficiency of the electric vehicle in each section of a predetermined driving distance based on the power consumption of the electric vehicle for each section, a long-distance power efficiency acquisition unit 52 that acquires the long-distance power efficiency based on the power consumption of the electric vehicle for driving distances longer than the predetermined driving distance, and a power efficiency calculation unit 53 that calculates the power efficiency of the electric vehicle using values ​​obtained by multiplying the latest section power efficiency, which is the section power efficiency for the latest section, and the long-distance power efficiency by weighting factors.

Description

Technical Field

[0001] The present invention relates to a system, program, and method for calculating the power efficiency of an electric vehicle by a computer.

Background Art

[0002] Using the electricity cost (power consumption rate) of an electric vehicle and the remaining battery level (remaining power), the cruising range of the electric vehicle is estimated. For example, Japanese Patent No. 5729191 (Patent Document 1) discloses an apparatus for estimating the cruising range of a vehicle. This apparatus calculates a first electricity cost based on the power consumption and the travel distance in a first sampling interval, and calculates a second electricity cost based on the power consumption and the travel distance in a second sampling interval that is longer than the first sampling interval. Before the initialization condition is satisfied, the apparatus estimates the cruising range estimate value using the first electricity cost, while when the initialization condition is satisfied, the apparatus estimates the cruising range estimate value using the second electricity cost.

[0003] In addition, Japanese Patent Application Laid-Open No. 2013-162618 (Patent Document 2) discloses a power consumption rate calculation apparatus for a vehicle that can perform electricity cost learning. In this electricity cost learning, the electricity cost (interval electricity cost) is calculated every predetermined time (for example, 5 minutes). The electricity cost learning is performed by reflecting this interval electricity cost on the learned electricity cost learned in the past.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The power efficiency of electric vehicles varies depending on the vehicle's operating environment. Therefore, for example, the power efficiency calculated using the conventional technology described above will change in accordance with the operating environment. As a result, the stability of the calculated power efficiency may be low.

[0006] Therefore, this application discloses a system, program, and method that enable the calculation of power efficiency taking into account responsiveness and stability to the driving environment. [Means for solving the problem]

[0007] The power efficiency calculation system for an electric vehicle in an embodiment of the present invention comprises: a section power efficiency acquisition unit that acquires the section power efficiency of the electric vehicle in each section based on the power consumption of the electric vehicle for each section of a predetermined driving distance; a long-distance power efficiency acquisition unit that acquires the long-distance power efficiency based on the power consumption of the electric vehicle over a driving distance longer than the predetermined driving distance; and a power efficiency calculation unit that calculates the power efficiency of the electric vehicle using the latest section power efficiency, which is the section power efficiency in the latest section acquired by the section power efficiency acquisition unit, and the long-distance power efficiency, each multiplied by a weighting coefficient. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a functional block diagram showing an example configuration of a drivable distance calculation system including a power efficiency calculation system in this embodiment. [Figure 2] Figure 2 is a left side view showing an example configuration of an electric assist bicycle, which is an example of an electric vehicle. [Figure 3] Figure 3 is a block diagram showing an example of the mechanical and electrical connection configuration of the components of the electric assist bicycle shown in Figure 2. [Figure 4] Figure 4 is a flowchart showing an example of the power efficiency calculation process using the power efficiency calculation system shown in Figure 1. [Figure 5] Figure 5 is a flowchart showing an example of the mileage calculation process using the mileage calculation system shown in Figure 1. [Figure 6]Figure 6 is a diagram illustrating an example of the process for calculating power efficiency for each driving mode. [Figure 7] Figure 7 illustrates another example of the process for calculating power efficiency for each driving mode. [Modes for carrying out the invention]

[0009] The power efficiency of electric vehicles varies depending on the driving environment and user habits. The driving environment tends to change over short distances. On the other hand, user habits tend to change less over long distances. Thus, the factors that affect power efficiency include factors that fluctuate over relatively short distances and factors that fluctuate over relatively long distances. The inventors have come up with a system that calculates power efficiency by balancing these multiple factors.

[0010] (Composition 1) The power efficiency calculation system for an electric vehicle in an embodiment of the present invention comprises: a section power efficiency acquisition unit that acquires the section power efficiency of the electric vehicle in each section based on the power consumption of the electric vehicle for each section of a predetermined driving distance; a long-distance power efficiency acquisition unit that acquires the long-distance power efficiency based on the power consumption of the electric vehicle over a driving distance longer than the predetermined driving distance; and a power efficiency calculation unit that calculates the power efficiency of the electric vehicle using the latest section power efficiency, which is the section power efficiency in the latest section acquired by the section power efficiency acquisition unit, and the long-distance power efficiency, each multiplied by a weighting coefficient.

[0011] According to the above configuration 1, the section power efficiency is obtained every time the electric vehicle travels a predetermined travel distance. Further, the long-distance power efficiency based on the power consumption at a distance of one section, that is, a travel distance longer than the predetermined travel distance, is obtained. Then, the power efficiency is calculated using the value obtained by multiplying the section power efficiency in the latest section by the weighting coefficient and the value obtained by multiplying the long-distance power efficiency by the weighting coefficient. These weighting coefficients adjust the weight of the factors that vary over a predetermined travel distance of one section and the weight of the factors that vary over a longer travel distance. Therefore, it is possible to calculate the power efficiency by taking the balance between the factors that vary over a relatively short travel distance and the factors that vary over a relatively long travel distance. As a result, it becomes possible to calculate the power efficiency considering the followability and stability to the driving environment.

[0012] Power efficiency is a value indicating the efficiency of the power for driving. The power efficiency may be, for example, a travel distance per unit amount of electrical energy, for example, a value indicating the distance that can be traveled with a unit capacity of an electrical energy source. Alternatively, the power efficiency may be a value indicating the amount of electrical energy per unit travel distance, that is, the amount of electrical energy required to travel a unit travel distance. The power efficiency can also be referred to as the electricity cost. The unit of power efficiency is not particularly limited, but may be, for example, km / Ah, m / Ah, m / As, km / Wh, m / Wh, m / Ws, Ah / m, Ah / km, As / m, Wh / km, Wh / m, or Ws / m, etc.

[0013] (Configuration 2) In the above configuration 1, the power efficiency calculation unit may calculate the power efficiency using the value obtained by adding the value obtained by multiplying the latest section power efficiency by (P-α) as a weighting coefficient and the value obtained by multiplying the long-distance power efficiency by α as a weighting coefficient. P is a constant, and 0 < α < P. Thereby, the power efficiency with adjusted weight can be efficiently calculated by simple processing.

[0014] In the above Configuration 1 or 2, the long-distance power efficiency may be, for example, the power efficiency for multiple sections calculated based on the power consumption in a plurality of sections, or the total travel distance power efficiency calculated based on the power consumption in the total travel distance of the electric vehicle.

[0015] The power efficiency for multiple sections may be calculated, for example, based on the power efficiency for each of the plurality of sections before the latest section. As an example, the power efficiency for multiple sections may be the previous power efficiency calculated by the power efficiency calculation unit for the section immediately before the latest section.

[0016] (Configuration 3) For example, in the above Configuration 1 or 2, the long-distance power efficiency acquisition unit may acquire the previous power efficiency calculated by the power efficiency calculation unit for the section immediately before the latest section as the long-distance power efficiency. The power efficiency calculation unit may calculate the power efficiency using values obtained by multiplying the latest section power efficiency and the previous power efficiency by a weighting coefficient, respectively.

[0017] Thereby, it becomes easier to ensure the followability of the power efficiency with respect to changes in the driving situation. As the travel distance of the electric vehicle increases, the number of past sections that form the basis of the long-distance power efficiency increases. According to Configuration 3 above, even when the driving situation changes significantly after the travel distance has increased, the followability of the power efficiency with respect to changes in the driving situation can be ensured. Note that Configuration 3 is an example when the long-distance power efficiency is the power efficiency for multiple sections.

[0018] (Configuration 4) In the above Configuration 1 or 2, the long-distance power efficiency acquisition unit acquires the total travel distance power efficiency calculated based on the power consumption in the total travel distance of the electric vehicle as the long-distance power efficiency, and the power efficiency calculation unit may calculate the power efficiency using values obtained by multiplying the latest section power efficiency and the total travel distance power efficiency by a weighting coefficient, respectively. Thereby, a power efficiency that takes into account the power consumption in the total travel distance and the power efficiency in the latest section in a well-balanced manner can be calculated.

[0019] The total driving distance of the electric vehicle may be, for example, the driving distance from when the electric vehicle was manufactured until now. For example, the total driving distance of the electric vehicle may be measured by an odometer provided in the electric vehicle.

[0020] (Configuration 5) A driving distance calculation system including the power efficiency calculation system according to any one of the above Configurations 1 to 4 is also included in an embodiment of the present invention. The driving distance calculation system includes a battery remaining amount acquisition unit that acquires the remaining amount of the battery provided in the electric vehicle, and a driving distance calculation unit that calculates a driving distance that can be traveled using the power of the battery of the electric vehicle using the power efficiency calculated by the power efficiency calculation unit and the remaining amount of the battery. An appropriate driving distance is calculated based on the power efficiency considering the followability and stability to the driving environment.

[0021] As an example, the weighting coefficient of the latest section power efficiency can be made larger than the weighting coefficient of the long-distance power efficiency. That is, P / 2 > α can be set. In this case, the contribution degree of the driving environment in the most recent section to the power efficiency can be made higher than the contribution degree of the factors in the past longer driving distance to the power efficiency. As a result, it is possible to calculate the power efficiency considering stability while enhancing the followability to the driving environment.

[0022] The weighting coefficient of the latest section power efficiency and the weighting coefficient of the long-distance power efficiency may be updatable according to an input from the user. Thereby, the user can adjust the balance between the followability and stability of the calculated power efficiency to the driving environment.

[0023] The predetermined driving distance may be updatable according to an input from the user. Thereby, the driving distance of one section can be adjusted.

[0024] The remaining amount of the battery may be calculated using, for example, the full charge capacity (FCC) and the remaining capacity ratio (RSOC) of the battery. Thereby, the remaining amount of the battery considering the degree of deterioration of the battery can be calculated.

[0025] (Composition 6) In the above configurations 1 to 5, the electric vehicle can switch between multiple driving modes using electricity according to the user's selection operation, and the power efficiency calculation unit may calculate the power efficiency of the driving mode selected by the user. The driving mode may be a mode of controlling the electric propulsion force in response to the propulsion force input by the user (e.g., pedaling force). For example, by switching the driving mode, the way in which the electric propulsion force responds to the propulsion force input by the user may be switched.

[0026] The power efficiency calculation unit may calculate the power efficiency of the selected driving mode by multiplying the selected mode's latest section power efficiency, which is the section power efficiency in the most recent section of the selected driving mode, and the selected mode's long-distance power efficiency, which is the long-distance power efficiency of the selected driving mode, by a weighting coefficient.

[0027] In this case, the section power efficiency acquisition unit may acquire the section power efficiency of the electric vehicle in each section of each driving mode based on the power consumption of the electric vehicle in each section of a predetermined driving distance for each driving mode. The long-distance power efficiency acquisition unit may acquire the long-distance power efficiency based on the power consumption of the electric vehicle in each driving mode over a driving distance longer than the predetermined driving distance.

[0028] Alternatively, the power efficiency calculation unit may calculate the power efficiency by correcting the value calculated using a weighting coefficient applied to each of the latest section power efficiency and long-distance power efficiency values, according to the selected driving mode. In this case, the section power efficiency acquisition unit may acquire the section power efficiency of the electric vehicle in each section based on the power consumption of the electric vehicle in each section of a predetermined driving distance for all driving modes. The long-distance power efficiency acquisition unit may acquire the long-distance power efficiency based on the power consumption of the electric vehicle over a driving distance of all driving modes that is longer than the predetermined driving distance.

[0029] The ratio or difference between the power consumption value of a selected driving mode and the average power consumption value of multiple driving modes may be used for the correction. The power consumption value may, for example, be a value indicating the amount of output of the motor equipped in the electric vehicle. The value indicating the amount of motor output may, for example, be the ratio of motor output for assistance to pedaling force (assist ratio). As an example, the average power consumption value of multiple driving modes can be the sum of the power consumption values ​​in each driving mode, weighted according to the usage time or distance of each mode, divided by the usage time or distance of all driving modes.

[0030] For example, the electric vehicle may be an electric assist bicycle, and the multiple riding modes may be multiple riding modes with different assist levels. In this case, a value representing the ratio or difference between the power consumption value of the assist level of the selected riding mode and the power consumption value of the average assist level of the multiple riding modes may be used for the correction. The assist level may be, for example, an assist ratio. As an example, a value representing the ratio of the motor output of the assist ratio of the selected riding mode to the motor output of the average assist ratio of the multiple riding modes may be used for the correction.

[0031] (Composition 7) In the above configurations 1 to 6, the electric vehicle may be an electric assist bicycle. An electric assist bicycle has a motor that outputs an assist force corresponding to the pedaling force input to the pedals. Since the power consumption of an electric assist bicycle when it is not in motion is negligible, power efficiency can be calculated without using data indicating the time of operation. Therefore, power efficiency can be calculated efficiently with a simple process.

[0032] The section power efficiency acquisition unit may acquire the section power efficiency each time the electric assist bicycle travels the predetermined distance, and the power efficiency calculation unit may calculate the power efficiency each time the electric assist bicycle travels the predetermined distance.

[0033] (Composition 8) In the above configuration 6 or 7, the electric vehicle is an electric assist bicycle, and the range of travel may be the assist range of travel with assistance using the power from the battery.

[0034] An electric assist bicycle may have multiple wheels, pedals to which the user's pedaling force is input to drive at least one of the multiple wheels, a motor to drive at least one of the multiple wheels, a battery to supply power to the motor, and a controller to control the assist force output by the motor in accordance with the pedaling force. The controller may switch between multiple riding modes with different assist levels in response to pedaling force, according to the user's selection.

[0035] An electric vehicle equipped with the above-described power efficiency calculation system or driving range calculation system is also included in embodiments of the present invention. The electric vehicle may be equipped with a display device that displays the power efficiency calculated by the power efficiency calculation system or the driving range calculated by the driving range calculation system.

[0036] The system in an embodiment of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description of those parts will not be repeated. In the following description, the front, rear, left, right, and up and down directions of an electric vehicle (for example, an electric assist bicycle) refer to the front, rear, left, right, and up and down directions relative to the state in which the user is riding. The front, rear, left, right, and up and down directions of the electric vehicle are the same as the front, rear, left, right, and up and down directions of the vehicle body, i.e., the vehicle frame. Also, the direction of travel of the electric vehicle is the same as the front, rear direction of the electric vehicle.

[0037] (Example system configuration) Figure 1 is a functional block diagram showing an example configuration of a mileage calculation system including a power efficiency calculation system in this embodiment. In the example in Figure 1, the power efficiency calculation system 50 calculates the power efficiency of the electric vehicle 10. The mileage calculation system calculates the mileage of the electric vehicle 10 based on the calculated power efficiency. In this embodiment, as an example, the electric vehicle 10 is an electric assist bicycle. The power efficiency calculation system 50 includes a section power efficiency acquisition unit 51, a long-distance power efficiency acquisition unit 52, and a power efficiency calculation unit 53. The mileage calculation system 5 further includes a mileage calculation unit 54 and a battery level acquisition unit 55.

[0038] The section power efficiency acquisition unit 51 acquires the section power efficiency x(n). The section power efficiency x(n) is the power efficiency based on the power consumption of the electric vehicle 10 for each section of a predetermined travel distance d. Here, n is a natural number and represents the section number. The x(k) when n=k is taken as the latest section power efficiency. The section power efficiency x(n) is calculated each time the electric vehicle 10 travels the predetermined travel distance d. In the example in Figure 1, the sections do not overlap with each other. That is, the power efficiency in each of the multiple sections of predetermined travel distance d that do not overlap with each other is calculated as the section power efficiency x(k). The section power efficiency x(n) for each section is calculated using the power consumption W(n) of the electric vehicle 10 in each section and the predetermined travel distance d. The section power efficiency acquisition unit 51 may acquire the calculated section power efficiency x(n), or it may calculate x(n) using the power consumption W(n). The section power efficiency acquisition unit 51 may, for example, acquire the latest section power efficiency x(k) when the journey to the most recent section is completed. As a result, the latest section power efficiency is acquired at the end of each section and becomes available to the power efficiency calculation system 50. The acquired latest section power efficiency x(k) is stored in a memory device accessible by the power efficiency calculation system.

[0039] The long-distance power efficiency acquisition unit 52 acquires the long-distance power efficiency Y. The long-distance power efficiency Y is the power efficiency based on the power consumption of the electric vehicle 10 over a distance longer than a predetermined distance d. The long-distance power efficiency Y may be calculated, for example, using the total distance dT measured by the odometer of the electric vehicle 10 and the power consumption WT during the journey over the total distance dT. Alternatively, the long-distance power efficiency Y may be the previous power efficiency y(k-1) calculated by the power efficiency calculation unit 53. The long-distance power efficiency acquisition unit 52 may acquire the calculated long-distance power efficiency Y, or it may calculate the long-distance power efficiency Y using the power consumption WT and the total distance dT. The long-distance power efficiency acquisition unit 52 may acquire the long-distance power efficiency Y, for example, when the journey over the most recent section is completed. As a result, the long-distance power efficiency Y is acquired at the end of each section and becomes available to the power efficiency calculation system 50. The acquired long-distance power efficiency Y is stored in a storage device accessible by the power efficiency calculation system.

[0040] The power efficiency calculation unit 53 calculates the power efficiency y(k) of the electric vehicle 10 using the values ​​obtained by multiplying the latest section power efficiency x(k) and the long-distance power efficiency Y by weighting coefficients. For example, the sum of the values ​​obtained by multiplying the latest section power efficiency x(k) and the long-distance power efficiency Y by weighting coefficients, or a corrected value of that sum, is calculated as the power efficiency y(k). As an example, the power efficiency y(k) may be calculated using the following formula with weighting coefficients α and a constant P. y(k) = (P - α) × x(k) + α × Y (0<α <P)

[0041] The power efficiency calculation unit 53 may calculate the power efficiency y(k) when the most recent section of travel is completed. This ensures that the power efficiency is calculated at the end of each section of travel. In other words, the power efficiency y(k) is updated each time the electric vehicle 10 travels a predetermined distance d. The power efficiency y(k) is stored in a memory device accessible by the power efficiency calculation system. The power efficiency y(k) can be described as the power efficiency learned based on the power efficiency of each section and the long-distance power efficiency, and can therefore be called the learned power efficiency.

[0042] The battery level acquisition unit 55 acquires the battery level of the battery provided in the electric vehicle 10. The battery level acquisition unit 55 may acquire the battery level from, for example, the battery control unit of the battery. Alternatively, the battery level may be calculated based on voltage, current, or other values ​​indicating the battery state acquired from the battery. The battery level may be calculated using, for example, the full charge capacity (FCC) and the relative state of charge (RSOC) relative to the FCC.

[0043] The mileage calculation unit 54 calculates the mileage using the power efficiency y(k) calculated by the power efficiency calculation unit 53 and the remaining battery charge. The mileage is the distance that the electric vehicle 10 can travel using the power from the battery. If the electric vehicle 10 is an electric assist bicycle, the mileage may be the remaining assist distance. If the power efficiency y(k) is expressed as the distance traveled per unit amount of electrical energy, the mileage can be calculated, for example, by y(k) × remaining battery charge. If the power efficiency y(k) is expressed as the amount of electrical energy per unit distance traveled, the mileage can be calculated, for example, by (1 / y(k)) × remaining battery charge.

[0044] The electric vehicle 10 may be able to switch between multiple driving modes according to the user's selection. In this case, the power efficiency calculation unit 53 may calculate the power efficiency of the driving mode selected by the user. For example, the section power efficiency acquisition unit 51 may acquire the section power efficiency of each driving mode, and the long-distance power efficiency acquisition unit 52 may acquire the long-distance power efficiency of each driving mode. In this case, the power efficiency calculation unit 53 can calculate the power efficiency y(k) of the selected driving mode using values ​​obtained by multiplying the section power efficiency and long-distance power efficiency of the selected driving mode by a weighting coefficient. Alternatively, the section power efficiency acquisition unit 51 may acquire the section power efficiency of all driving modes, and the long-distance power efficiency acquisition unit 52 may acquire the long-distance power efficiency of all driving modes. In this case, the power efficiency calculation unit 53 can calculate the power efficiency y(k) by correcting the values ​​obtained by multiplying the section power efficiency and long-distance power efficiency by a weighting coefficient according to the selected driving mode.

[0045] The electric vehicle 10 may include a plurality of wheels, a motor that drives at least one of the plurality of wheels, a battery that supplies power to the motor, a mileage detector, and a power consumption detector. The mileage detector may include, for example, a rotation sensor that detects the rotation of the wheels of the electric vehicle 10. The rotation sensor detects the rotation of the wheels or a rotating body that rotates in conjunction with the rotation of the wheels. Each time the mileage detector detects that a predetermined mileage d has been traveled, the section power efficiency acquisition unit 51 can acquire the section power efficiency. The power consumption detector may, for example, detect the discharge power of the battery as power consumption. Alternatively, the power consumption detector may detect the power consumed by the motor as power consumption. The section power efficiency acquisition unit 51 can acquire the section power efficiency calculated based on the power consumption of each section detected by the power consumption detector.

[0046] The power efficiency calculation system and the driving range calculation system are implemented by one or more computers. That is, each functional part of the power efficiency calculation system and the driving range calculation system can be realized by the computer executing a program. The computer may consist of, for example, a CPU, an MPU (Micro Processing Unit), an MCU (Micro Controller Unit), a PLD (Programmable Logic Device), an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or other ICs. The program that executes the processing of the power efficiency calculation system and the driving range calculation system, and a non-transitory storage medium that stores the program are also included in embodiments of the present invention.

[0047] The power efficiency calculation system and the driving range calculation system may be implemented, for example, in an on-board computer mounted on the electric vehicle 10. In this case, the power efficiency, section power efficiency, and long-distance power efficiency calculated by the power efficiency calculation unit may be stored in an on-board storage device mounted on the electric vehicle 10. The on-board computer or on-board storage device may be, for example, a computer included in the drive unit 40, UI unit 70, or display device 71 of an electric assist bicycle, as described later, or in other on-board devices. Note that devices that can be attached to and detached from the electric vehicle 10, such as a cycle computer (cycle meter) or a smartphone, are also included in the on-board devices. The computer or storage device included in such a detachable device may be an on-board computer or on-board storage device.

[0048] (Example of an electric assist bicycle configuration) Figure 2 is a left side view showing an example configuration of an electric assist bicycle, which is an example of an electric vehicle 10. In Figure 2, the symbols F, B, U, and D represent the front, rear, top, and bottom, respectively. The electric assist bicycle comprises multiple wheels 21, 22, a frame 11, a motor 3, a crankshaft 41, and pedals 31. The multiple wheels 21, 22, the crankshaft 41, and the pedals 31 are rotatably supported relative to the frame 11. The electric assist bicycle also has a transmission mechanism that transmits the rotation of the motor 3 to at least one of the wheels 21, 22, and a transmission mechanism that transmits the pedaling force applied to the pedals 31 and crankshaft 41 to at least one of the wheels 21, 22. At least one of the wheels 21, 22 is driven by at least one of the pedaling force of the pedals 31 or the driving force of the motor 3.

[0049] The electric assist bicycle is equipped with a pedal force sensor 62 that detects the user's pedaling force. The pedal force sensor 62 is mounted around the crankshaft 41. The pedal force sensor 62 detects the torque that rotates the crankshaft 41 around its axis. The pedal force sensor 62 can be a non-contact type such as a magnetostrictive type, or a contact type torque sensor such as an elastic variable detection type. A magnetostrictive torque sensor has a magnetostrictive effect and includes a magnetostrictive material that receives the rotational force of the crankshaft, and a detection coil that detects the change in magnetic permeability due to the force of the magnetostrictive material.

[0050] The electric assist bicycle has a distance sensor 61. The distance sensor 61 may also function as a vehicle speed sensor. The distance sensor 61 is installed, for example, on the front fork 26. The distance sensor 61 includes, for example, a detection element that rotates with the front wheel 21 (wheel) and a detection element fixed to the vehicle frame 11 that detects the rotation of the detection element. The detection element detects the detection element mechanically, magnetically, or optically. The distance sensor 61 is not limited to the front wheel 21, but may also detect the rotation of a rotating body that rotates as the electric vehicle 10 moves, such as the rear wheel 22, motor 3, crankshaft 41, transmission gear, chain, etc. For example, the distance traveled is detected by multiplying the number of rotations of the detected rotating body by the tire circumference (the distance traveled in one rotation of the tire). The vehicle speed is detected by multiplying the number of rotations of the rotating body per unit time by the tire circumference.

[0051] A battery unit 35 is located on the vehicle frame 11. The battery unit 35 supplies power to the motor 3 of the drive unit 40. The battery unit 35 includes a battery and a battery control unit (not shown). The battery is a rechargeable battery that can be charged and discharged. The battery control unit controls the charging and discharging of the battery and monitors the battery's output current, discharge power, and remaining capacity. However, the monitoring targets of the battery control unit are not limited to these. For example, the battery control unit does not need to monitor the discharge power. In this case, for example, the electric vehicle controller 500 (see Figure 3) can calculate the discharge power using the battery current and voltage supplied from the battery control unit.

[0052] Electric assist bicycles are equipped with a user interface (UI) unit 70 that accepts various operations from the user. The UI unit 70 has, for example, input devices 72 such as buttons or touch panels that accept user operations. The UI unit 70 may also include a display device (display) 72. In this case, the display device 71 and the input device 72 may be integrated to form a touch panel. Various information related to the electric vehicle 10 is displayed on the display device 71. For example, at least one of the power efficiency calculated by the power efficiency calculation unit 53 or the travel distance calculated by the travel distance calculation unit 54 may be displayed on the display device 71. The input device 72 may, for example, accept user operations to select a riding mode. The UI unit 70 may be composed of a detachable device attached to the electric vehicle 10, such as a cycle meter or a smartphone.

[0053] Figure 3 is a block diagram showing an example of the mechanical and electrical connection configuration of the components of the electric assist bicycle shown in Figure 2. In the example shown in Figure 3, the rotation of the pedal 31 is transmitted to the combined force mechanism 43 via a one-way clutch 49d. The rotation of the motor 3 is transmitted to the combined force mechanism 43 via a reduction gear 32 and a one-way clutch 49c. The combined force mechanism 43 includes, for example, a combining mechanism, a drive sprocket, a chain, and a driven sprocket. The combining mechanism combines the rotation of the crankshaft 41 and the rotation of the motor 3 and transmits it to the drive sprocket. In the combined force mechanism 43, power is transmitted in the order of the combining mechanism, the drive sprocket, the chain 46, and the driven sprocket. The rotation of the driven sprocket is transmitted to the rear wheel 22 via the drive shaft 44, the gear shift mechanism 48, and the one-way clutch 49a. The gear shift mechanism 48 is a mechanism that changes the gear ratio in response to the operation of the gear shift lever 47 by the rider.

[0054] The pedaling force generated when the rider presses down on the pedal 31 rotates the crankshaft 41 in the forward rotation direction. The rotation of the crankshaft 41 is transmitted to the rear wheel 22 by the transmission mechanism. In addition, the rotational force generated when the motor 3 operates rotates the crankshaft 41 in the forward rotation direction. As a result, the rotational force of the motor 3 is transmitted as a driving force that rotates the rear wheel 22 in the forward rotation direction. When the rider's pedaling force and the rotational force of the motor 3 are transmitted to the crankshaft simultaneously, the rotational force of the motor 3 assists (supports) the rider's pedaling force. As a modification, the rotational force of the motor 3 may be configured to be transmitted to the front wheel 21. That is, the transmission mechanism may be configured to transmit the rotation of the motor to a wheel different from the wheel to which the rotation of the crankshaft 41 is transmitted. In this case, a combining mechanism that combines the pedaling force and the motor output becomes unnecessary.

[0055] In the example shown in Figure 3, the electric assist bicycle has a controller 500. The controller 500 includes a mileage calculation system 5 and a power efficiency calculation system 50 (hereinafter sometimes simply referred to as systems 5 and 50). For example, the controller 500 is configured by a computer mounted on a circuit board inside the housing 40a of the drive unit 40. The controller 500, i.e., systems 5 and 50, is electrically connected to a mileage sensor 61, a pedal force sensor 62, a motor 3, a battery unit 35, and a UI unit 70. These connections may be wired or wireless.

[0056] The controller 500 controls the output of the motor 3 according to the pedal force detected by the pedal force sensor 62. The controller 500 causes the motor 3 to output an assist force corresponding to the pedal force. The way in which the motor 3 responds to the pedal force may be controlled to differ depending on the driving mode. For example, the controller 500 may switch between multiple driving modes, each with a different assist level for the pedal force, according to the user's selection.

[0057] (Example of power efficiency calculation process) Figure 4 is a flowchart illustrating an example of the power efficiency calculation process by the power efficiency calculation system 50 shown in Figure 1. In S01, the section power efficiency acquisition unit 51 acquires the latest section power efficiency x(k). The latest section power efficiency x(k) is calculated, for example, by converting the discharge power W(k) during the latest section's predetermined driving distance d to discharge power per unit distance (W(k) / d) or driving distance per unit power (d / W(k)). The discharge power W(k) during the latest section's driving may, for example, be the sum of the battery's discharge power during the driving of the predetermined section's predetermined driving distance d. The driving of the predetermined driving distance d can be detected by the driving distance sensor 61. The battery's discharge power can be obtained, for example, from the battery control unit 351 of the battery unit 35.

[0058] As an example, the discharge energy W(k)[Ws] during the most recent section of travel can be calculated using the following formula. Note that the unit of energy is not limited to [Ws], and may also be Wh, mWh, mWs, As, Ah, or mAs, for example.

number

[0059] In S02, the long-distance power efficiency acquisition unit 52 acquires the long-distance power efficiency Y. The long-distance power efficiency Y is calculated, for example, using the total travel distance dT and the total power consumption WT during the travel of the total travel distance dT. As an example, the long-distance power efficiency Y may be calculated as dT / WT or WT / dT. The total travel distance dT can be calculated, for example, by accumulating the travel distance detected by the travel distance sensor 61. The total power consumption WT can be calculated, for example, by accumulating the discharge power of the battery unit 35.

[0060] As another example, the long-distance power efficiency Y may be the previous power efficiency y(k-1) calculated by the power efficiency calculation unit 53 for the section immediately preceding the most recent section. In other words, the long-distance power efficiency may be the previously learned power efficiency. The power efficiency calculation unit 53 calculates the power efficiency for each section. That is, when the electric vehicle 10 completes a section of a predetermined distance d, the power efficiency is calculated based on the power efficiency of the most recent section (with that section being the most recent section) and the long-distance power efficiency. Therefore, the previous power efficiency y(k-1) is the power efficiency calculated based on the power efficiency of each of the multiple sections from the first section to the section immediately preceding the most recent section. Note that in calculating the power efficiency after completing the first section, a predetermined value (default value) may be used for the long-distance power efficiency.

[0061] The power efficiency calculation unit 53 calculates the power efficiency y(k) using the latest section power efficiency x(k) obtained in S01 and the long-distance power efficiency Y obtained in S02. For example, y(k) can be calculated using the formula shown in Figure 4, y(k) = (1-α) × x(k) + α × Y. α is a weighting coefficient, and in this example, 0 < α < 1. The power efficiency y(k) may be converted to a different unit as needed. For example, if the unit of the calculated power efficiency y(k) is energy per kilometer (for example, the unit is [mWs / km]), it can be converted to a power efficiency ye(k) in units of distance traveled per Wh [m / Wh] using the following formula. ye(k) = (3600 × 1000 × 1000) / y(k)

[0062] (Example of calculation process for remaining driving distance) Figure 5 is a flowchart showing an example of the driving range calculation process by the driving range calculation system 5 shown in Figure 1. In S04, the battery level acquisition unit 55 acquires the battery level. The battery level can be calculated, for example, by the following formula. The battery level may be calculated, for example, by the battery control unit 351 of the battery unit 35, or by the battery level acquisition unit 55. Battery level [Wh] = FCC [Wh] × RSOC [%] / 100

[0063] The travelable distance calculation unit 54 calculates the travelable distance by multiplying the power efficiency calculated in S03 by the remaining battery level acquired in S04. The travelable distance is, for example, the remaining assistable distance. The travelable distance is calculated by, for example, the following formula. The calculated travelable distance is displayed on, for example, a display device provided in the electric vehicle 10. Travelable distance [m] = Power efficiency [m / Wh] × Remaining battery level [Wh]

[0064] The travelable distance calculation process in FIG. 5 may be executed at a timing independent of the power efficiency calculation process in FIG. 4. For example, the travelable distance calculation may be executed at a fixed cycle. Or, the travelable distance may be calculated every time the electric vehicle travels a travelable distance ds (ds < d) shorter than a predetermined travelable distance d in one section. Or, at least, the travelable distance may be calculated契机に when the power efficiency is calculated, that is, when the power efficiency is updated.

[0065] In the process of FIG. 4 above, the power efficiency learned based on the power efficiency of the latest section and the long-distance power efficiency is calculated. Therefore, the power efficiency reflecting the user's individual usage conditions such as the driving environment, the user's usage method, and the characteristics of the electric vehicle is calculated. In the process of FIG. 5, since the travelable distance is calculated using this power efficiency, the travelable distance suitable for the user's usage conditions is calculated. Therefore, the deviation between the travelable distance presented to the user and the distance that can actually be traveled using electricity can be reduced.

[0066] It should be noted that in the translation of the sentence in , "契机に" is directly translated as "契机に" here because it seems to be a specific term in the original text. If there is a more accurate English equivalent, it can be further adjusted. Also, the overall translation tries to follow the original text structure and technical terms as closely as possible while ensuring the English is grammatically correct.Furthermore, in the above example, it is possible to set a weighting coefficient α. By adjusting the weighting coefficient α, the responsiveness and stability of the calculated power efficiency or drivable distance to changes in the driving environment can be adjusted. The weighting coefficient α determines the ratio of contributions from the latest section power efficiency and the long-distance power efficiency. Increasing the weighting coefficient α increases the proportion of the long-distance power efficiency. In this case, the fluctuation in the calculated power efficiency in response to changes in usage conditions becomes smaller, and stability increases. Decreasing the weighting coefficient α increases the proportion of the latest section power efficiency. In this case, the responsiveness of the calculated power efficiency to changes in usage conditions increases. The weighting coefficient α can also be called a filter coefficient.

[0067] In S02 of Figure 4, by setting the long-distance power efficiency Y to the previous power efficiency y(k-1), the ability of the calculated power efficiency to respond to changes in usage conditions can be improved compared to the case where the long-distance power efficiency Y is the power efficiency of the total distance traveled. When the long-distance power efficiency Y is the power efficiency of the total distance traveled, the ability of the calculated power efficiency to respond to changes in usage conditions slows down as the total distance traveled increases. In contrast, when the long-distance power efficiency Y is set to the previous power efficiency y(k-1), the ability to respond can be ensured. This is because the power efficiency of older sections is compressed, and the contribution of the power efficiency of newer sections increases. For example, if the usage conditions suddenly change after the total distance traveled by the electric vehicle has increased (for example, moving, or purchasing a used electric vehicle 10), the calculated power efficiency can be made to respond to the change without delay.

[0068] (Example of power efficiency calculation for each driving mode) The electric vehicle 10 may be able to switch between multiple driving modes using electricity according to the user's selection. If the electric vehicle 10 is an electric assist bicycle, the multiple driving modes may be multiple driving modes with different assist levels. For example, the multiple driving modes may include an eco mode with a low assist level to reduce power consumption, a normal mode with an average assist level that provides standard assistance, and a high mode with a high assist level that provides powerful assistance. The power efficiency calculation unit 53 may be configured to calculate the power efficiency of the driving mode selected by the user. This allows the power efficiency of the selected driving mode and the driving distance for that driving mode to be calculated and presented to the user when the user selects and switches driving modes.

[0069] Figure 6 is a diagram illustrating an example of the process for calculating power efficiency for each driving mode. In the example in Figure 6, for each of the driving modes 1 to 3, the section power efficiency xi(n) is calculated for each section of a predetermined driving distance d. That is, the section power efficiency acquisition unit 51 acquires the section power efficiency xi(n) for each section of each driving mode. i is the driving mode number. In this example, i = 1, 2, 3. The long-distance power efficiency acquisition unit 52 acquires the long-distance power efficiency Yi for each driving mode. The long-distance power efficiency Yi may be the total driving distance for each driving mode, or it may be the previous power efficiency for each driving mode. The power efficiency calculation unit 53 calculates the power efficiency of the selected driving mode using the latest section power efficiency xi(k) of the selected driving mode i and the long-distance power efficiency Yi of the selected driving mode multiplied by a weighting coefficient.

[0070] Figure 7 illustrates another example of the process for calculating power efficiency for each driving mode. In the example in Figure 7, the section power efficiency x(n) is calculated for each section of a predetermined driving distance d in all driving modes. That is, the section power efficiency x(n) is obtained each time the predetermined driving distance d is traveled, regardless of the selected driving mode. The long-distance power efficiency is the power efficiency based on the power consumption for driving distances longer than d in all driving modes. That is, the power efficiency based on the power consumption when traveling a distance longer than d, regardless of the driving mode, is obtained as the long-distance power efficiency. The power efficiency calculation unit 53 calculates the power efficiency yi(k) of driving mode i by correcting the value y(k), which is calculated using the latest section power efficiency x(n) and the long-distance power efficiency, according to the selected driving mode i. For example, the power efficiency yi(k) of the corrected driving mode i is calculated by using a correction value corresponding to the selected driving mode i in the value y(k). The correction value may be, for example, the ratio or difference of the power consumption of the selected driving mode to the average power consumption of multiple driving modes.

[0071] In the example in Figure 7, the usage amount zi for each driving mode is calculated. The usage amount zi for each driving mode is, for example, the time during which the assist level i of each driving mode i was used. The usage amount for each driving mode is not limited to the usage time of each driving mode, but may also be a value indicating the distance traveled in each driving mode, the frequency of use of each driving mode, or other usage amounts. Based on the usage amount zi for each driving mode, the average power consumption of multiple driving modes and the power consumption of each driving mode are calculated. The correction value for the selected driving mode is determined using a value that indicates the ratio of the power consumption of the selected driving mode to the average power consumption. For example, the power efficiency yi(k) of the selected driving mode is calculated by multiplying the power efficiency y(k) of all driving modes by the correction value of the selected driving mode i.

[0072] In the example in Figure 7, y(k) is corrected using the value M(pi) / M(E), which represents the ratio of the motor output degree M(pi) of the selected driving mode i's assist ratio pi to the motor output degree M(E) of the average assist ratio E of multiple driving modes. Equation 1 in Figure 7 shows an example of calculating the average assist ratio E. Equation 2 shows an example of calculating the power efficiency yi(k) of the selected driving mode i. In Equation 2, M(pi) / M(E) is used as the correction value. The assist ratio is the ratio of motor output to the input pedal force. For example, the assist ratio can be the ratio of motor output when the pedal force is set to 1. Note that in Equation 2 in Figure 7, the unit of power efficiency yi(k) is an example where the unit is energy per unit distance (e.g., [mWs / km]). If the unit of power efficiency is driving distance per unit power (e.g., m / Wh), the correction value is the reciprocal of M(pi) / M(E).

[0073] In the example in Figure 6, the power efficiency yi(k) for each driving mode is calculated using the section power efficiency xi(k) and long-distance power efficiency Yi for each driving mode. In this case, differences in the frequency of use of driving modes may result in differences in the learning progress of power efficiency for each driving mode. Differences in learning progress may disrupt the correlation between, for example, the assist level and the calculated power efficiency or remaining assistable distance. In contrast, in the example in Figure 7, the power efficiency yi(k) for each driving mode is calculated by correcting the section power efficiency x(k) and long-distance power efficiency Yi, which are common to all driving modes, i.e., multiple driving modes. In this way, by calculating a single learned power efficiency for driving in multiple driving modes and correcting it to calculate the power efficiency for each driving mode, it is possible to avoid inconsistencies in calculation results due to differences in learning progress among driving modes.

[0074] Note that the process of correcting y(k) to calculate the power efficiency yi(k) of driving mode i is not limited to the example in Figure 7. For example, in addition to motor output, values ​​related to motor power consumption, battery discharge power, and other power consumption may be used as correction values. Also, in the example in Figure 7, the correction value is calculated using the average value of multiple driving modes and the value for each driving mode, but a predetermined fixed value may be used as the correction value for each driving mode.

[0075] The method for calculating the section power efficiency of each section obtained by the section power efficiency acquisition unit 51 is not limited to the above example. For example, the section power efficiency of each section may be calculated using a moving average of the power consumption or power efficiency of each sub-section obtained by further dividing each section. For example, the section power efficiency may be calculated using the moving average obtained by sequentially calculating the average power consumption of the sub-sections within the most recent section for each sub-section run, as the power consumption of each section. In this case, each section will overlap with other sections. Also, the section power efficiency is calculated for each sub-section. Alternatively, the section power efficiency may be calculated using a representative value (e.g., the average value) of the moving average of the power consumption of multiple sub-sections included in one section, as the power consumption of one section. In this case, each section will not overlap with other sections, and the section power efficiency can be calculated for each section.

[0076] (Example of setting the predetermined driving distance d) The predetermined driving distance d can be set based on the characteristics of the electric vehicle 10. If the electric vehicle 10 is an electric assist bicycle, the predetermined driving distance d can be set in the range of, for example, 1m to 20km. For example, by setting the predetermined driving distance d in the range of 1m to 5km, it is possible to calculate power efficiency and driving distance that closely follow changes in the usage conditions of the electric assist bicycle. From the viewpoint of requiring fine-grained responsiveness, for example, 1m ≤ d ≤ 1km is preferred, 1m ≤ d ≤ 500m is more preferred, and 1m ≤ d ≤ 250m is even more preferred. Furthermore, from the viewpoint of responsiveness to changes in average daily usage conditions, for example, 100m ≤ d ≤ 15km is preferred, 100m ≤ d ≤ 10km is more preferred, and 100m ≤ d ≤ 5km is even more preferred.

[0077] (Example configuration of the weighting factor α) The weighting factor α, although not limited to this, can be set such that, for example, P / 2 > α. This makes the contribution of the latest interval power efficiency higher than that of the long-distance power efficiency. Therefore, it becomes easier to calculate power efficiency with a balance between adaptability to usage conditions and stability. When emphasizing adaptability, P / 5 > α is preferable, and P / 10 > α is even more preferable. When emphasizing stability, P / 2 < α is preferable, and P / 5 < α is even more preferable. Note that 0 < α < P. The constant P is not particularly limited, and for example, P = 1×10^n (n is an integer) may be used.

[0078] Also, the weighting factor α may be set in consideration of the relationship with a predetermined travel distance d. For example, when the predetermined travel distance d is increased, the driving environment is averaged and stability is enhanced. Therefore, α can be decreased to increase adaptability and achieve a balance. When the predetermined travel distance d is decreased, the driving environment is not averaged and stability is reduced. Therefore, α can be increased to lower adaptability and achieve a balance. The ranges of α and d are not limited to this, but for example, when 100m ≤ d ≤ 10km, setting P / 2 > α > P / 100 results in a better balance between adaptability and stability.

[0079] At least one of the weighting factor α and the predetermined travel distance d may be updatable according to user input. The power efficiency calculation system 50 may receive an input of an update instruction for at least one of the weighting factor α and the predetermined travel distance d. For example, an update instruction from the user is input via the input device 72 of the UI unit 70 provided in the electric vehicle 10. When receiving the input of the update instruction, the power efficiency calculation system 50 may receive input from the user regarding both the adaptability level and the stability level. In this case, updated values of α and d may be determined according to the adaptability level and the stability level input by the user. The weighting factor α and the predetermined travel distance d are recorded in a recording device accessible to the power efficiency calculation system 50.

[0080] The electric vehicle in the embodiment of the present invention may be an electric assist bicycle, or for example, an electric bicycle, or an electric two-wheeled vehicle with pedals (electric moped), etc. Furthermore, the electric vehicle is not limited to a two-wheeled vehicle, but may be a vehicle having three or more wheels.

[0081] The embodiments of the present invention have been described above, but the embodiments described above are examples for carrying out the present invention. This is merely an illustration. Therefore, the present invention is not limited to the embodiments described above, nor does it deviate from its spirit. It is possible to implement the above-described embodiments by appropriately modifying them within the limits that do not deviate from the original design. [Explanation of Symbols]

[0082] 3: Motor, 5: Driving range calculation system, 50: Power efficiency calculation system, 51: Section power efficiency acquisition unit, 52: Long-distance power efficiency acquisition unit, 53: Power efficiency calculation unit, 54: Driving range calculation unit, 55: Battery level acquisition unit

Claims

1. A section power efficiency acquisition unit that acquires the section power efficiency of the electric vehicle in each section based on the power consumption of the electric vehicle for each section of a predetermined distance, A long-distance power efficiency acquisition unit that acquires the long-distance power efficiency based on the power consumption of the electric vehicle over a distance longer than the predetermined distance, A power efficiency calculation system for an electric vehicle, comprising: a power efficiency calculation unit that calculates the power efficiency of the electric vehicle using the latest section power efficiency, which is the section power efficiency in the latest section obtained by the section power efficiency acquisition unit, and the long-distance power efficiency, each multiplied by a weighting coefficient.

2. A power efficiency calculation system according to claim 1, The power efficiency calculation unit calculates the power efficiency using the sum of the latest section power efficiency multiplied by a weighting coefficient of (P - α) and the long-distance power efficiency multiplied by a weighting coefficient of α, where P is a constant and 0 < α < P.

3. A power efficiency calculation system according to claim 1 or 2, The long-distance power efficiency acquisition unit acquires the previous power efficiency calculated by the power efficiency calculation unit for the section immediately preceding the most recent section as the long-distance power efficiency. The power efficiency calculation unit calculates the power efficiency using the latest section power efficiency and the previous power efficiency, each multiplied by a weighting coefficient, as a power efficiency calculation system.

4. A power efficiency calculation system according to claim 1 or 2, The long-distance power efficiency acquisition unit acquires the total mileage power efficiency calculated based on the power consumption over the total mileage of the electric vehicle as the long-distance power efficiency. The power efficiency calculation unit calculates the power efficiency using values ​​obtained by multiplying the latest section power efficiency and the total distance traveled power efficiency by weighting coefficients.

5. A system for calculating the driving range of an electric vehicle, comprising the power efficiency calculation system described in claim 1 or 2, A battery level acquisition unit that acquires the remaining battery level of the battery equipped in the electric vehicle, A system for calculating the distance that can be traveled using the power from the battery of an electric vehicle, comprising: a distance calculation unit that calculates the distance that can be traveled using the power from the battery of the electric vehicle, using the power efficiency calculated by the power efficiency calculation unit and the remaining battery charge.

6. A power efficiency calculation system according to claim 1 or 2, The electric vehicle is capable of switching between multiple driving modes using electricity according to the user's selection. The aforementioned power efficiency calculation unit is a power efficiency calculation system that calculates the power efficiency of the driving mode selected by the user.

7. A power efficiency calculation system according to claim 1 or 2, The aforementioned electric vehicle is an electric assist bicycle having a motor that outputs an assist force corresponding to the pedaling force input to the pedals, and the power efficiency calculation system is also described.

8. A system for calculating the drivable distance according to claim 5, The electric vehicle in question is an electric assist bicycle. A system for calculating the range of possible travel, wherein the range of possible travel is the assisted travel distance during which the vehicle can travel with assistance using the power from the battery.

9. A section power efficiency acquisition process that acquires the section power efficiency of the electric vehicle in each section based on the power consumption of the electric vehicle for each section of a predetermined distance, A long-distance power efficiency acquisition process that acquires the long-distance power efficiency based on the power consumption of the electric vehicle over a distance longer than the predetermined distance, A power efficiency calculation process calculates the power efficiency of the electric vehicle using the latest section power efficiency, which is the section power efficiency in the latest section obtained by the section power efficiency acquisition process, and the long-distance power efficiency, each multiplied by a weighting coefficient. A program that uses a computer to calculate the power efficiency of electric vehicles.

10. A method for calculating the power efficiency of an electric vehicle, performed by a computer, A section power efficiency acquisition step is to acquire the section power efficiency of the electric vehicle in each section based on the power consumption of the electric vehicle for each section of a predetermined distance, A long-distance power efficiency acquisition step is to acquire the long-distance power efficiency based on the power consumption of the electric vehicle over a distance longer than the predetermined driving distance, A power efficiency calculation step, which calculates the power efficiency of the electric vehicle using the latest section power efficiency, which is the section power efficiency in the latest section obtained in the section power efficiency acquisition step, and the long-distance power efficiency, each multiplied by a weighting coefficient, A method for calculating the power efficiency of an electric vehicle, comprising the following:

Images