Electric vehicle

Abstract

To provide an electric vehicle capable of reproducing the behavior of a transmission vehicle, which visually notifies a driver of a shift operation timing.SOLUTION: An electric vehicle has an electric motor as a driving source. The electric vehicle includes: an accelerator pedal; a pseudo transmission operation member imitating an operation member used for a transmission operation of a transmission vehicle; a display device performing display for a driver; a vehicle speed sensor; and a control device controlling a torque of the electric motor according to an accelerator pedal. The control device executes switching a relation between an acceleration opening and a torque of the electric motor to the vehicle speed according to the operation of the pseudo transmission operation member, displaying an indicator where the display is continuously changed interlocking with a driving wheel torque and the vehicle speed on a display device, and notifying the driver of a timing when the operation of the pseudo transmission operation member is recommended, by the indicator.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to an electric vehicle having an electric motor as a drive source. [Background technology]

[0002] Patent Document 1 discloses a hybrid vehicle equipped with a meter display device that can be switched from a power meter display to a tachometer display by operating a switch. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6947051 Summary of the Invention [Problem to be solved by the invention]

[0004] There are known electric vehicles that can simulate the behavior of a vehicle equipped with a manual transmission (transmission vehicle) powered by an engine by controlling an electric motor. In these electric vehicles, the gear shifting of a transmission vehicle can also be replicated, allowing the driver to manually perform simulated gear shifting operations. In such vehicles, we are considering how to notify the driver of the timing of gear shifting operations in an easy-to-understand manner.

[0005] One object of the present disclosure is to provide a technology that can visually notify the driver of the timing of a virtually reproduced gear shift in an electric vehicle that can reproduce the behavior of a transmission vehicle. [Means for solving the problem]

[0006] The present disclosure provides an electric vehicle having an electric motor as a drive source. The electric vehicle includes an accelerator pedal used for driving, a pseudo-shift operation member that simulates an operation member used to change gears in a transmission vehicle, a display device for displaying information to the driver, a vehicle speed sensor that measures the vehicle speed of the electric vehicle, and a control device that controls the torque of the electric motor in response to operation of the accelerator pedal. The control device is configured to switch the relationship between the accelerator pedal position and the torque of the electric motor in response to operation of the pseudo-shift operation member, display an indicator on the display device that continuously changes its display in response to drive wheel torque and vehicle speed, and notify the driver, via the indicator, of the timing when it is recommended to operate the pseudo-shift operation member. [Effects of the Invention]

[0007] According to the electric vehicle of the present disclosure, the timing when a pseudo gearshift operation using the pseudo gearshift operating member is recommended is notified by an indicator displayed on the display device. Furthermore, the display of the indicator changes continuously according to the state of the vehicle. By notifying the driver of the recommended gearshift operation through an indicator that changes continuously according to the state of the vehicle rather than simply notifying the driver of the recommended gearshift operation in a one-off manner, the driver can visually grasp the timing of the gearshift operation in an easily understandable manner. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a configuration of an electric vehicle according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram showing the configuration of a control device related to driving control of an electric vehicle. [Figure 3] FIG. 4 is a graph showing the relationship between virtual engine rotation speed and virtual engine torque. [Figure 4] FIG. 10 is a diagram for explaining indicators displayed by an electric vehicle according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is a diagram illustrating an example of a map for determining the length of a bar. [Figure 6]FIG. 10 is a diagram for explaining changes in maps depending on modes. [Figure 7] FIG. 10 is a diagram illustrating an example of a display on an indicator. [Figure 8] FIG. 10 is a diagram showing another example of display on the indicator. [Figure 9] 10A and 10B are diagrams illustrating examples of changes to the display on the indicator. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0010] 1. Electric vehicle power system configuration 1 is a diagram schematically illustrating the configuration of an electric vehicle 100 according to an embodiment of the present disclosure. First, the configuration of the power system of the electric vehicle 100 will be described with reference to FIG.

[0011] The electric vehicle 100 is equipped with two electric motors (M) 4F, 4R at the front and rear as a power source for driving. The electric motors 4F, 4R are, for example, three-phase AC motors. The front electric motor 4F is connected to a front drive shaft 5F that drives the front wheels 6F. The rear electric motor 4R is connected to a rear drive shaft 5R that drives the rear wheels 6R. The front wheels 6F are suspended by independent left and right electronically controlled front suspensions 7F. The rear wheels 6R are suspended by independent left and right electronically controlled rear suspensions 7R.

[0012] The front electric motor 4F and the rear electric motor 4R are respectively equipped with inverters (INV) 3F and 3R. The front inverter 3F and the rear inverter 3R are each connected to a battery (BATT) 2. The battery 2 stores electrical energy to drive the electric motors 4F and 4R. In other words, the electric vehicle 100 is a battery electric vehicle (BEV) that runs on electrical energy stored in the battery 2. The inverters 3F and 3R are, for example, voltage-type inverters, and control the torque of the electric motors 4F and 4R by PWM control.

[0013] 2. Electric vehicle control system configuration Next, the configuration of the control system of the electric vehicle 100 will be described with reference to FIG.

[0014] The electric vehicle 100 is equipped with a battery management system (BMS) 10. The battery management system 10 is a device that monitors the cell voltage, current, temperature, etc. of the battery 2. The battery management system 10 has a function of estimating the state of charge (SOC) of the battery 2.

[0015] The electric vehicle 100 is equipped with a vehicle speed sensor 11. At least one of wheel speed sensors (not shown) provided on each of the left and right front wheels 6F and the left and right rear wheels 6R is used as the vehicle speed sensor 11. The electric vehicle 100 is also equipped with an accelerator pedal stroke sensor 12. The accelerator pedal stroke sensor 12 is provided on an accelerator pedal 22 and outputs a signal indicating the amount of depression of the accelerator pedal 22, i.e., the accelerator opening. The electric vehicle 100 is also equipped with a brake pedal stroke sensor 13. The brake pedal stroke sensor 13 is provided on a brake pedal 23 and outputs a signal indicating the amount of depression of the brake pedal 23, i.e., the brake opening.

[0016] The accelerator pedal 22 and the brake pedal 23 are driving operation members used to drive the electric vehicle 100. In addition to these driving operation members, the electric vehicle 100 is equipped with pseudo gearshift operation members that imitate operation members used to change gears in a transmission vehicle. The pseudo gearshift operation members include a pseudo H-shifter 24, a pseudo paddle shifter 25, and a pseudo clutch pedal 26, which will be described below.

[0017] The pseudo-H-shaped shifter 24 is a dummy that is different from an actual H-shaped shifter. The pseudo-H-shaped shifter 24 has a structure that resembles a shift stick mounted on a console, and can be moved along an H-shaped gate between shift positions. However, because the electric vehicle 100 does not have an actual transmission, the shift positions of the pseudo-H-shaped shifter 24 are virtual shift positions. The pseudo-H-shaped shifter 24 is provided with a shift position sensor 14. The shift position sensor 14 outputs a signal that indicates the shift position selected by the pseudo-H-shaped shifter 24.

[0018] The pseudo paddle shifter 25 is a dummy that is different from a real paddle shifter, which is a type of sequential shifter. The pseudo paddle shifter 25 has a structure similar to shift paddles attached to the steering wheel, and the left and right paddles can be moved independently. The pseudo paddle shifter 25 is equipped with a paddle shift switch 15. The paddle shift switch 15 outputs an upshift signal when the right paddle is pulled, and outputs a downshift signal when the left paddle is pulled.

[0019] The pseudo clutch pedal 26 is a dummy that is different from an actual clutch pedal. The pseudo clutch pedal 26 has a structure similar to that of a clutch pedal provided in a conventional transmission vehicle. For example, the pseudo clutch pedal 26 is equipped with a reaction force mechanism that generates a reaction force when the driver presses down on the pedal. The position when no pressure is applied to the pseudo clutch pedal 26 is the starting position of the pseudo clutch pedal 26, and the position when the pseudo clutch pedal is pressed down to the fullest extent is the end position of the pseudo clutch pedal 26. The driver can operate the pseudo clutch pedal 26 from the starting position to the end position against the reaction force from the reaction force mechanism. The pseudo clutch pedal 26 is equipped with a clutch pedal stroke sensor 16. The clutch pedal stroke sensor 16 outputs a signal indicating the amount of depression of the pseudo clutch pedal 26. Because the electric vehicle 100 does not have an actual clutch, the operation amount of the pseudo clutch pedal 26, i.e., the clutch opening, is a virtual clutch opening.

[0020] Although the pseudo clutch pedal 26 is a pedal-type operating device operated by foot, a lever-type operating device or a dial-type operating device operated by hand may also be provided as the pseudo clutch operating device. The pseudo clutch operating device can be configured in a variety of ways as long as the driver can operate it from the start position to the end position against a reaction force and the operating feel is similar to that of a clutch pedal provided in a conventional transmission vehicle.

[0021] The electric vehicle 100 also includes a human-machine interface (HMI) 20 as an interface with the driver, a display device 21, and an in-vehicle speaker 27. The HMI 20 includes a touch panel display. The HMI 20 displays information on the touch panel display and accepts input from the driver via touch operations on the touch panel display. The display device 21 is provided, for example, on a meter panel, and is capable of displaying a reproduced transmission vehicle state on the display in the MT mode described below. The in-vehicle speaker 27 provides information to the driver by voice and is also capable of outputting a simulated engine sound described below.

[0022] The electric vehicle 100 is equipped with a control device 101. Sensors and devices to be controlled mounted on the electric vehicle 100 are connected to the control device 101 via an in-vehicle network. In addition to a battery management system 10, a vehicle speed sensor 11, an accelerator pedal stroke sensor 12, a brake pedal stroke sensor 13, a shift position sensor 14, a paddle shift switch 15, and a clutch pedal stroke sensor 16, the electric vehicle 100 is also equipped with various other sensors.

[0023] The control device 101 is typically an electronic control unit (ECU). The control device 101 may be a combination of multiple ECUs. The control device 101 includes at least a processor 102 and a memory 103. The memory 103 includes a RAM for temporarily storing data and a ROM for storing a program 104 executable by the processor 102 and various data 105 related to the program. The program 104 is made up of multiple instructions. The processor 102 reads and executes the program 104 and data 105 from the memory 103, and generates control signals based on signals acquired from each sensor. The control device 101 may include one or more processors 102.

[0024] The control device 101 can control the electric vehicle 100 in various control modes. The driver can select a control mode by touching the touch panel display of the HMI 20. More specifically, by touching the touch panel display of the HMI 20, one or more programs 104 associated with each touch operation are read from the memory 103 and executed by the processor 102. Below, we will explain the control modes of the electric vehicle 100 by the control device 101 that the driver can select by operating the HMI 20.

[0025] 3. Electric vehicle control mode The control modes of the electric vehicle 100 that can be selected by the control device 101 include an EV mode and an MT mode. The driver can select the control mode from a selection screen displayed on the touch panel display of the HMI 20.

[0026] When the EV mode is selected, the control mode of the electric vehicle 100 switches to the EV mode. The EV mode is a mode in which the electric motor is controlled with normal torque characteristics to drive the vehicle. In the EV mode, the driver can basically drive the electric vehicle 100 by operating only the accelerator pedal 22, the brake pedal 23, and the steering wheel (not shown). In the EV mode, the shift operation of the pseudo H-type shifter 24, the shift operation of the pseudo paddle shifter 25, and the clutch operation of the pseudo clutch pedal 26 are disabled.

[0027] When the MT mode is selected, the control mode of the electric vehicle 100 switches to the MT mode. The MT mode is a control mode that causes the electric vehicle 100 to operate like a transmission vehicle. In the MT mode, a virtual shift position (gear stage) is reproduced, allowing the driver to manually perform a pseudo-shift operation.

[0028] In the MT mode, the driver may be able to select a more detailed control mode. For example, the driver may be able to select an option for the shift mode of a manual transmission reproduced in the electric vehicle 100. The shift modes include a paddle shift mode and a stick shift mode. The paddle shift mode is a mode in which the pseudo paddle shifters 25 are used for shifting operations. In the paddle shift mode, the shift operation of the pseudo H-type shifter 24 is disabled. In the paddle shift mode, the operation when the gear ratio of a manual transmission is changed is reproduced by the shift operation of the pseudo paddle shifters 25. Note that the clutch operation in a real paddle shift-type manual transmission is automatically performed by the robot. Therefore, in the paddle shift mode, clutch operation of the pseudo clutch pedal 26 is not required. In the paddle shift mode, clutch operation of the pseudo clutch pedal 26 is disabled.

[0029] Stick shift mode is a mode in which the pseudo H-type shifter 24 is used for shifting. In stick shift mode, shifting of the pseudo paddle shifters 25 is disabled. In stick shift mode, the operation of a manual transmission when changing gear ratios is reproduced by shifting of the pseudo H-type shifter 24. In stick shift mode, the driver may further select either clutch operation or clutch-less operation. In a genuine H-type manual transmission, there are those in which the clutch operation is performed by the driver themselves and those in which clutch operation is performed by a robot. When clutch operation is selected, the stick shift mode switches to a mode requiring clutch operation of the pseudo clutch pedal 26. On the other hand, when clutch-less stick operation is selected, clutch operation of the pseudo clutch pedal 26 is disabled, and the stick shift mode switches to a mode requiring no clutch operation.

[0030] The driver may also be able to select options related to engine characteristics, engine sound, drive mode, suspension characteristics, etc. By appropriately combining these options, the driver can determine the characteristics of a transmission vehicle that he or she wants electric vehicle 100 to simulate. In this way, by operating the touch panel display of HMI 20, the control mode of electric vehicle 100 can be switched to suit the driver's preferences.

[0031] Such control modes that can be switched by the driver relate to the driving control of the electric vehicle 100. In the next chapter, the driving control of the electric vehicle 100 by the control device 101 will be described.

[0032] 4. Electric vehicle driving control Fig. 2 is a diagram showing the configuration of the control device 101 related to the driving control of the electric vehicle 100. In detail, Fig. 2 shows the configuration related to torque control in particular among the driving control. The processor 102 executes one or more driving control programs 104 stored in the memory 103, causing the processor 102 to function as a driving control device.

[0033] A control mode signal is input from the HMI 20 to the control device 101, which functions as a driving control device. The control mode signal includes information about the control mode selected by the driver. The control device 101 executes process P110 based on the control mode signal. In process P110, the control mode is switched in accordance with the control mode signal. The control mode switching that particularly affects driving control is the switch between EV mode and MT mode.

[0034] When the control mode is switched to EV mode, the control device 101 executes process P120 for torque calculation in EV mode. In process P120, the control device 101 obtains the vehicle speed from the signal of the vehicle speed sensor 11 and obtains the accelerator opening from the signal of the accelerator pedal stroke sensor 12. The control device 101 has a motor torque map that uses the accelerator opening and vehicle speed as parameters. The control device 101 inputs the vehicle speed and accelerator opening into the motor torque map and controls the inverters 3F, 3R so that the electric motors 4F, 4R generate the torque obtained from the motor torque map.

[0035] When the control mode is switched to MT mode, the control device 101 executes process P130 for calculating torque in MT mode. Process P130 includes process P131 for calculating torque to be generated at the drive wheels. Process P130 also includes process P132 and process P133. Process P132 is for calculating torque to be generated at the front electric motor 4F, and process P133 is for calculating torque to be generated at the rear electric motor 4R. Processes P132 and P133 are executed in accordance with the drive wheel torque calculated in process P130 and the torque distribution between the front wheels 6F and the rear wheels 6R.

[0036] A vehicle model MOD01 is used to calculate the drive wheel torque in process P131. The vehicle model MOD01 includes an engine model MOD11, a clutch model MOD12, and a transmission model MOD13. The engine virtually realized by the vehicle model MOD01 is called a virtual engine, the clutch virtually realized is called a virtual clutch, and the transmission virtually realized is called a virtual transmission. The engine model MOD11 models the virtual engine. The clutch model MOD12 models the virtual clutch. The transmission model MOD13 models the virtual transmission.

[0037] The engine model MOD11 calculates a virtual engine speed and a virtual engine torque. The virtual engine speed is calculated from the vehicle speed, the overall reduction ratio, and the slip ratio of the virtual clutch. The virtual engine torque is calculated from the virtual engine speed and the accelerator opening. The vehicle speed is obtained from a signal from the vehicle speed sensor 11. The accelerator opening is obtained from a signal from the accelerator pedal stroke sensor 12. The overall reduction ratio is a value obtained by multiplying the gear ratio of the virtual transmission by the reduction ratio determined by the mechanical structure from the virtual transmission to the drive wheels. In the engine model MOD11, the relationship between the virtual engine speed and the virtual engine torque is specified for each accelerator opening. The engine characteristics of the engine model MOD11 may be selectable by the driver by operating the HMI 20.

[0038] The clutch model MOD12 calculates a torque transmission gain. The torque transmission gain is a gain used to calculate the degree of torque transmission of the virtual clutch according to the clutch opening. When the stick shift mode with clutch operation is selected as the shift mode, the clutch opening is obtained from the signal of the clutch pedal stroke sensor 16. The clutch opening is 0% at the start position of the pseudo clutch pedal 26 and 100% at the end position of the pseudo clutch pedal 26. The clutch model MOD12 assigns a torque transmission gain to the clutch opening. The torque transmission gain is converted into the clutch torque capacity of the virtual clutch, i.e., the virtual clutch torque capacity. The virtual clutch torque input from the virtual clutch to the virtual transmission is calculated based on a comparison between the virtual clutch torque capacity and the virtual engine torque calculated by the engine model MOD11. The clutch model MOD12 also calculates a slip ratio by subtracting the torque transmission gain from 1. The slip ratio is used to calculate the virtual engine speed in the engine model MOD11.

[0039] When the paddle shift mode is selected as the shift mode, the clutch opening degree input to the clutch model MOD12 is calculated using the clutch operation model. Also, when the clutch operation-less stick shift mode is selected as the shift mode, the clutch opening degree input to the clutch model MOD12 is calculated using the clutch operation model. The clutch operation model is a model that simulates the clutch operation of a model driver. When the paddle shift mode is selected, the clutch operation model receives the vehicle speed, virtual engine RPM, and a signal from the paddle shift switch 15. When the clutch operation-less stick shift mode is selected, the clutch operation model receives the vehicle speed, virtual engine RPM, and a signal from the shift position sensor 14.

[0040] The signals from the paddle shift switch 15 and the shift position sensor 14 are used to determine the timing of clutch operation. When a driver's shift operation is detected by the signals from the paddle shift switch 15 and the shift position sensor 14, the clutch operation model maximizes the clutch opening so as to disengage the virtual clutch. The vehicle speed and virtual engine RPM are used to calculate the clutch opening. The clutch operation model calculates the clutch opening based on the rotational speed difference between the rotational speed of the input shaft of the virtual transmission, which is calculated from the vehicle speed, and the virtual engine RPM so that the rotational speed of the input shaft of the virtual transmission smoothly matches the virtual engine RPM.

[0041] The transmission model MOD13 calculates a virtual gear ratio. The virtual gear ratio is a gear ratio determined by the virtual shift position (virtual gear) in the virtual transmission. A virtual gear ratio is set for each shift position. The maximum virtual gear ratio is set for first gear, and the virtual gear ratios decrease in the order of second gear, third gear, fourth gear, and so on. In stick shift mode, the shift positions are in one-to-one correspondence with the signal from the shift position sensor 14.

[0042] In the paddle shift mode, the shift position is increased by one step in response to an upshift signal from the paddle shift switch 15, and decreased by one step in response to a downshift signal from the paddle shift switch 15. Note that while the number of shift positions is physically determined in the pseudo H-type shifter 24, there are no physical restrictions on the number of shift positions in the pseudo paddle shifter 25. Therefore, the transmission model MOD13 may be different between the stick shift mode and the paddle shift mode, and the number of shift positions in the paddle shift mode may be greater than the number of shift positions in the stick shift mode.

[0043] The transmission model MOD13 calculates a virtual transmission torque using the virtual gear ratio and the virtual clutch torque. The virtual transmission torque is a virtual torque output from the virtual transmission. The control device 101 controls the inverters 3F, 3R so that the output torque of the electric motors 4F, 4R changes according to the virtual transmission torque. The virtual transmission torque changes discontinuously according to the switching of the virtual gear ratio. This discontinuous change in the virtual transmission torque generates a torque shock in the electric vehicle 100, creating the appearance of a vehicle equipped with a stepped transmission.

[0044] The vehicle model MOD01 calculates drive wheel torque from the virtual transmission torque and reduction ratio. The drive wheel torque is the sum of the torques acting on the left and right front wheels 6F and the left and right rear wheels 6R. The torque distribution between the front wheels 6F and the rear wheels 6R can be fixed or can be changed actively or passively. The torque distribution may be selectable by the driver; when a mode that drives only the rear wheels is selected, the drive wheel torque is the sum of the torques acting on the left and right rear wheels 6R.

[0045] In process P132, the torque of the front electric motor 4F in the MT mode (front motor torque) is calculated by multiplying the drive wheel torque calculated in process P131 by the torque distribution rate to the front wheels 6F and the reduction ratio from the output shaft of the front electric motor 4F to the front wheels 6F. The control device 101 controls the front inverter 3F so that the front electric motor 4F generates the front motor torque calculated in process P132.

[0046] In process P133, the torque of the rear electric motor 4R in MT mode (rear motor torque) is calculated by multiplying the drive wheel torque calculated in process P131 by the torque distribution rate to the rear wheels 6R and the reduction ratio from the output shaft of the rear electric motor 4R to the rear wheels 6R. The control device 101 controls the rear inverter 3R so that the rear electric motor 4R generates the rear motor torque calculated in process P133.

[0047] 2, the battery management system 10 and the brake pedal stroke sensor 13 are not necessarily required for the above-described driving control. However, if switching the control mode affects the SOC of the battery 2, the signal from the battery management system 10 may be used as information for determining whether or not to switch the control mode. Furthermore, in cases where the operation method of the electric vehicle 100 changes significantly, such as switching between EV mode and MT mode, the condition for switching may be whether the brake pedal 23 is depressed. In this case, the signal from the brake pedal stroke sensor 13 can be used as information for determining whether the brake pedal 23 is depressed.

[0048] 5. Sound control for electric vehicles The control device 101 may also perform sound control to control the sound emitted from the in-vehicle speaker 27. The processor 102 functions as a sound control device by executing one or more sound control programs 104 stored in the memory 103. The processor 102 functioning as the torque control device and the processor 102 functioning as the sound control device may be separate processors or may be the same processor.

[0049] The control device 101 as a sound control device can generate artificially generated sounds from the in-vehicle speaker 27. One of the artificial sounds is a pseudo engine sound that imitates the engine sound of a transmission vehicle. When a control mode signal indicating that the MT mode has been selected is input from the HMI 20, the control device 101 as a sound control device generates the pseudo engine sound based on the virtual engine torque and virtual engine speed calculated in process P131.

[0050] When the driver can select an engine sound, the engine sound selected by the HMI 20 is used as the sound source for the pseudo engine sound to be generated from the in-vehicle speaker 27. However, the sound of the sound source is not used as is; the sound pressure of the engine sound is calculated so that the greater the virtual engine torque, the greater the sound pressure, and the frequency of the engine sound is calculated so that the greater the virtual engine speed, the higher the frequency. Then, for example, the sound pressure of the sound source is changed by an amplifier, and the frequency of the sound source is changed by a frequency modulator, and the pseudo engine sound is reproduced from the in-vehicle speaker 27. The virtual engine torque and virtual engine speed change depending on the driver's accelerator operation, gear shift operation, and clutch operation. In this way, by changing the sound pressure and frequency of the pseudo engine sound in accordance with the virtual engine torque and virtual engine speed that change in accordance with the driver's operation, the driver can be given a sense of realism as if they were driving a vehicle with a real transmission.

[0051] 6. Notification of gear shift operation timing (first embodiment) As described above, the driver of electric vehicle 100 can experience the operation of a transmission vehicle in electric vehicle 100 by operating HMI 20 to switch the control mode to MT mode. In MT mode, which is one of the operations that simulates a transmission vehicle, the driver can manually perform a pseudo gear change operation (shift change) and switch the virtual shift position.

[0052] In a normal transmission vehicle, the timing to perform a gear shift is not explicitly notified. However, the driver can determine the timing to perform a gear shift based on the vehicle speed, engine RPM, etc. The concept of the timing to perform a gear shift is basically the same in the MT mode of the electric vehicle 100. In other words, even without an explicit notification, the driver can determine the timing to perform a gear shift based on the vehicle speed, virtual engine RPM, etc., and select a shift position that matches the state of the virtual transmission vehicle. However, it would be more convenient for the driver if the timing to perform a gear shift was visually notified.

[0053] Therefore, the electric vehicle 100 notifies the driver of the appropriate timing for shifting gears by displaying information on the display device 21. The notification by the electric vehicle 100 will be described below.

[0054] The timing of gear shifting can be considered based on the magnitude of the virtual engine speed and virtual engine torque. Figure 3 is a graph showing the relationship between the virtual engine speed and the maximum virtual engine torque. The maximum virtual engine torque relative to the virtual engine speed is determined by the vehicle model MOD01, and the shaded area is the range within which the virtual engine torque can be obtained.

[0055] Within the shaded area, the ellipse (1) indicates the approximate area where a downshift is recommended, the ellipse (2) indicates the approximate area when a shift position appropriate for the state of the virtual transmission vehicle is selected, and the ellipse (3) indicates the approximate area where an upshift is recommended. When the virtual engine speed and virtual engine torque are in the area (1), it is believed that downshifting will provide greater torque and make driving more comfortable for the driver, when in the area (2), it is believed that driving is possible in an area where torque can be fully utilized, and when in the area (3), it is believed that the area where the maximum virtual engine torque can be obtained has been exceeded and therefore upshifting would make driving more comfortable.

[0056] The white arrow in the shaded area indicates how the virtual engine speed and virtual engine torque change when the driver depresses the accelerator pedal 22 at a certain virtual shift position. The lower left side of the arrow is in a region where downshifting would be more comfortable. As the accelerator pedal 22 is depressed from this position, the virtual engine speed and virtual engine torque gradually increase, moving into a region where the current shift position is considered appropriate. As the accelerator pedal 22 is further depressed, the virtual engine speed and virtual engine torque increase further, entering a region where an upshift is recommended.

[0057] The display device 21 displays an indicator that shows the changes in the virtual engine speed and virtual engine torque by changing the length of a bar, and the timing at which a gear change is recommended is notified by the change in the length of the bar.

[0058] Figure 4 shows how the length of the bar changes in response to changes in virtual engine RPM and virtual engine torque. The positions (a) through (d) in the upper graph correspond to the displays (a) through (d) below. As shown in Figure 4, when the virtual engine RPM and virtual engine torque are located to the lower left of the white arrow, the length of the bar is shortened, and as the virtual engine RPM and virtual engine torque increase, the length of the bar gradually increases. The possible end positions of the bar are divided into three areas: a downshift recommendation area where a downshift is recommended, an area where the current shift position is recommended, and an upshift recommendation area where an upshift is recommended. When the end position falls within the upshift recommendation area, an upshift is indicated, and when the end position falls within the downshift recommendation area, a downshift is indicated.

[0059] In this way, the driver is visually notified of the timing when a gear shift is recommended by changing the length of the bar. The length of the bar also changes continuously to match the state of the virtual transmission vehicle reproduced in MT mode. Therefore, the driver can also see from the display how much margin there is before reaching the area where a downshift or upshift is recommended, making it easier for the driver to intuitively grasp the timing of a gear shift. In the example of Figure 4, both states (b) and (c) are in an area where the current shift position is considered appropriate. However, state (b) allows the driver to visually grasp that there is a margin before reaching the area where an upshift is recommended, whereas state (c) shows that there is little margin. This is an effect that cannot be achieved by a device that simply notifies the driver of the timing of a gear shift.

[0060] 3 and 4, the virtual engine speed and virtual engine torque do not necessarily change along the white arrows. However, even when the positions representing the virtual engine speed and virtual engine torque are not on the white arrows, the current virtual engine speed and virtual engine torque can be replaced with the length of the bar. In other words, the amount of time remaining until the timing of an upshift when the accelerator pedal 22 is depressed, or the amount of time remaining until the timing of a downshift when the accelerator pedal 22 is released, can be predicted based on the current virtual engine speed and virtual engine torque, and can be replaced with the length of the bar. Therefore, the length of the bar can be determined depending on where the virtual engine speed and virtual engine torque are within the range, and the timing at which a gear change is recommended can be notified by the continuously changing length of the bar.

[0061] A method for calculating the bar length will be described with reference to FIG. 5. FIG. 5 is a map showing the bar lengths corresponding to the virtual engine speed and the virtual engine torque. The color depth represents the bar length, with lighter areas representing shorter bars and darker areas representing longer bars. For a given virtual engine speed, the larger the virtual engine torque, the longer the bar. For a given virtual engine torque, the larger the virtual engine speed. Note that in the map shown in FIG. 5, the values ​​representing the magnitude of the virtual engine speed and the virtual engine torque do not necessarily correspond to the actual values ​​of the virtual engine speed and the virtual engine torque calculated by the vehicle model MOD01. For example, the values ​​of the virtual engine speed and the virtual engine torque may be replaced with scores, or a map may be set based on the scores. The map is prepared in advance and stored in memory 103. The bar length is calculated from the values ​​of the virtual engine speed and the virtual engine torque based on the map.

[0062] 7. Other embodiments 7-1. Second embodiment The above is the basic embodiment. Various modified embodiments will be described below. In a second embodiment, the map that determines the length of the bar is variable depending on the driving mode.

[0063] Figure 6 shows examples of three driving modes and their corresponding maps. Three driving modes are selectable: normal mode, eco mode, and sport mode. The top map shows the map for normal mode, the bottom left map shows the map for eco mode, and the bottom right map shows the map for sport mode. Normal mode is a map corresponding to typical shift change timing. In eco mode, the bar length is increased in the region where the virtual engine torque is low compared to normal mode. In other words, a notification recommending an upshift is issued from a relatively low virtual engine speed and virtual engine torque. By encouraging an early upshift in this way, the output of drive wheel torque can be reduced, thereby reducing battery 2 consumption. Sport mode is a mode that promotes so-called "pull driving," and compared to normal mode, the bar length is reduced as the virtual engine speed increases. In other words, the upshift timing is delayed compared to normal mode.

[0064] In this way, by changing the map according to the driving mode, the timing of shift changes can be notified according to the driver's preferences and the situation. When the map is changed according to the driving mode, the length of the bar set for the same virtual engine RPM and virtual engine torque may be changed, or the method of calculating the score based on the virtual engine RPM and virtual engine torque may be changed. Each driving mode may be selected arbitrarily by the driver operating the HMI 20. Alternatively, the driving mode may be automatically changed by the control device 101. For example, the control device 101 may obtain information from the battery management system 10 and automatically set the driving mode to eco mode when the remaining battery charge is low. The above three driving modes are merely examples, and the number of driving modes and their corresponding maps may be more or less than three, and the maps provided are not limited to those shown in FIG. 6.

[0065] 7-2.Third embodiment The third embodiment is a modification of the second embodiment. In the second embodiment, the timing of the notification prompting the driver to upshift or downshift is variable depending on the driving mode. In contrast, in the third embodiment, the rate of change in the length of the bar is variable depending on the driving mode.

[0066] For example, maps corresponding to two driving modes, normal mode and strong notification mode, are prepared. The virtual engine speed and virtual engine torque when the end position of the bar enters the downshift recommended area or the upshift recommended area are set to be equal in both maps. In other words, the timing of the notification prompting a downshift or upshift is the same in both modes. However, in strong notification mode, the rate of change of the bar length near the downshift recommended area or the upshift recommended area is increased. Because the bar length changes rapidly when entering the area where a shift change is recommended, it is easier for the driver to visually recognize that a notification is being given.

[0067] These two modes may be selectable by the driver or may be automatically set by the control device 101. The third embodiment may also be combined with the second embodiment. In other words, both the timing at which a shift change is notified and the rate at which the bar length changes near the upshift recommended region or the downshift recommended region may be made variable depending on the driving mode.

[0068] 7-3. Fourth embodiment (variation of display method) The indicator displayed on the display device 21 is not limited to being represented by a linear bar. Fig. 7 is a diagram showing an example of a method for displaying a bar. The bar may be displayed in a curved shape within a circular display area, as shown here.

[0069] Furthermore, in the indicator, the color of the bar may change as the length of the bar changes. For example, the color of the bar may change continuously as the length of the bar changes. Alternatively, the color of the bar may change gradually as the terminal position of the bar enters the downshift recommended region or the upshift recommended region. Alternatively, the bar may flash when the terminal position of the bar enters the downshift recommended region or the upshift recommended region, either in conjunction with or instead of changing color. Changing the color or flashing the color makes it easier for the driver to know that the downshift recommended region or the upshift recommended region has been entered.

[0070] Furthermore, the indicator display does not have to be a bar. In the example of FIG. 8, the downshift recommended area, the upshift recommended area, and the area where an appropriate shift position can be selected are indicated by circular areas. The blackened circular area represents the current state of the virtual transmission vehicle, and its size changes continuously in accordance with changes in the state of the virtual transmission vehicle. The display may be represented by a change in area in this way.

[0071] As such, the indicator may be any indicator that visually conveys continuous changes according to the state of the virtual transmission vehicle, and there are no limitations on the display method. Examples of indicators include a display in which a numerical value, color, area of ​​a graphic, bar length, or a combination of these changes continuously changes. Note that even when a display other than bar length is used as the indicator, the displayed parameters can be calculated using a map such as that shown in FIG. 5. For example, the area and color can be determined using a map such as that shown in FIG. 5.

[0072] 7-4. Fifth embodiment (divided areas) In the example of Figure 4, the possible positions of the end of the bar are divided into three areas: a downshift recommended area, an upshift recommended area, and an area where gear shifting is not required. By dividing the timing of gear shifting into three simple areas like this, it becomes easier for the driver to clearly grasp the timing of gear shifting.

[0073] The size of each of these three regions may be variable depending on the driver's selection. FIG. 9 shows an example of how the regions are divided. (e) is a method of dividing the regions in the normal mode. In contrast, (f) is a method of dividing the regions in a mode for drivers who want to actively downshift. In the display example shown here, the downshift recommendation region is wider than in the normal mode, and the upshift recommendation region is narrower than in the normal mode. In this way, the size of each region may be variable.

[0074] Furthermore, in the indicator display, the possible positions of the bar's end point may be further divided into smaller regions. For example, in the example (g), the possible ranges of the bar's end point are divided into four regions: a downshift recommended region, a large output margin region, a region where driving is possible with an appropriate shift position, and a recommended upshift region. The "large output margin" region indicates that there is a margin up to the region where maximum virtual engine torque can be obtained and that there is a depression on the accelerator pedal 22. Within this region, it is possible to continue driving with the current virtual shift position, or to downshift to obtain greater acceleration. Displaying such regions in addition to the recommended downshift region can serve as a guide for drivers who want to actively downshift.

[0075] In this way, by displaying more subdivided areas using the indicator, the driver can grasp the state of the virtual transmission vehicle in more detail. Note that the indicator display may be fixed to either the display divided into three areas or the more subdivided display, or may be switchable at the driver's discretion or automatically by the control device 101.

[0076] 8. Summary As described above, in the electric vehicle according to this embodiment, the driver is notified of the timing at which it is recommended to switch the virtual shift position by a continuously changing display. Because the display continuously changes in accordance with the state of the virtual transmission vehicle, the driver can visually and easily grasp the timing of the gear shift operation reproduced in the MT mode. This improves drivability. Note that the above-described multiple embodiments can be combined as appropriate. [Explanation of symbols]

[0077] 2 Battery, 3F Front inverter, 3R Rear inverter, 4F Front electric motor, 4R Rear electric motor, 5F Front drive shaft, 5R Rear drive shaft, 6F Front wheel, 6R Rear wheel, 7F Front suspension, 7R Rear suspension, 10 Battery management system, 11 Vehicle speed sensor, 12 Accelerator pedal stroke sensor, 13 Brake pedal stroke sensor, 14 Shift position sensor, 15 Paddle shift switch, 16 Clutch pedal stroke sensor, 21 Display device, 22 Accelerator pedal, 23 Brake pedal, 24 Pseudo H-type shifter, 25 Pseudo paddle shifter, 26 Pseudo clutch pedal, 27 In-car speaker, 100 Electric vehicle, 101 Control device, 102 Processor, 103 Memory, 104 Program, 105 Data

Claims

1. An electric vehicle having an electric motor as a drive source, an accelerator pedal used to drive the electric vehicle; a pseudo-speed change operation member that simulates an operation member used for speed change operations of a transmission vehicle; a display device for displaying information to a driver; a vehicle speed sensor for measuring the vehicle speed of the electric vehicle; a control device that controls the torque of the electric motor in response to operation of the accelerator pedal, The control device switching a relationship between the accelerator pedal opening degree and the torque of the electric motor relative to the vehicle speed in response to operation of the pseudo speed change operation member; displaying on the display device an indicator whose display continuously changes in conjunction with the drive wheel torque and the vehicle speed of the electric vehicle; and notifying the driver by the indicator of the timing at which it is recommended to operate the pseudo speed-change operating member. An electric vehicle characterized by:

2. 2. The electric vehicle according to claim 1, The indicator is an indicator that displays a bar whose length changes continuously. An electric vehicle characterized by:

3. 3. The electric vehicle according to claim 2, The indicator is an indicator that displays a bar whose color changes continuously as its length changes. An electric vehicle characterized by:

4. 2. The electric vehicle according to claim 1, The indicator is an indicator that displays a figure whose area changes continuously. An electric vehicle characterized by:

5. The electric vehicle according to any one of claims 1 to 4, The indicator is displayed on the meter panel. An electric vehicle characterized by:

6. 3. The electric vehicle according to claim 2, the control device changes the relationship between the drive wheel torque and the vehicle speed and the length of the bar in response to a selection by the driver. An electric vehicle characterized by:

7. 7. The electric vehicle according to claim 6, The control device has, as display modes of the bar, a first mode and a second mode in which the length of the bar is changed so that the bar reaches its maximum length in a region of higher rotation than in the first mode. An electric vehicle characterized by:

8. 7. The electric vehicle according to claim 6, The control device has, as display modes of the bar, a first mode and a third mode in which the length of the bar is changed so that the bar reaches its maximum length in a region with lower torque and rotation than in the first mode. An electric vehicle characterized by:

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