Electric vehicle and program for controlling electric vehicle

Abstract

The invention relates to an electric vehicle and a program for controlling the electric vehicle. The electric vehicle has an electric motor as a drive source. An electric vehicle is provided with an accelerator pedal used in the driving of the electric vehicle, an analog sequential shifter, and a processor for controlling the electric vehicle in accordance with the operation of the accelerator pedal. The simulation sequential shifter simulates a sequential shifter used in a shift operation of a manual shift diesel locomotive, and is provided in a steering gear. The processor executes a control mode in which the operation of the analog sequential shifter is associated with a virtual gear, which is a virtual gear, and the opening degree of an accelerator pedal, the virtual gear, the vehicle speed of the electric vehicle, and the torque of an electric motor, in accordance with the selection of the driver. When the steering angle of the steering wheel is equal to or greater than a predetermined angle during execution of the control mode, the processor automatically downshifts the virtual gear according to the vehicle speed.

Description

Technical Field

[0001] The present disclosure relates to an electric vehicle having an electric motor as a drive source and a program for controlling the electric vehicle. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2021-151168 discloses a technique related to an electric vehicle capable of simulating and reproducing a manual shifting operation of a vehicle equipped with a manual transmission having an internal combustion engine as a power source (hereinafter referred to as a manual transmission internal combustion engine vehicle) by controlling an electric motor. A driver of the electric vehicle can select a plurality of virtual gear stage modes (virtual gears) by a paddle switch or the like. The paddle switch is a shifting device (hereinafter referred to as an analog sequential shifter) of an analog sequential shifter provided in a steering gear. Summary of the Invention

[0003] According to the above technique, it is possible to experience the shifting operation of a manual transmission internal combustion engine vehicle in an electric vehicle. At this time, the driver can select a virtual gear that reproduces the gear of the manual transmission internal combustion engine vehicle by an analog sequential shifter. However, when the analog sequential shifter is provided in the steering gear, when the steering gear is largely steered to turn the electric vehicle, the positional relationship between the hand placed on the steering wheel and the analog sequential shifter changes. Therefore, in a state where the steering angle of the steering gear becomes large, it is difficult for the driver to smoothly operate the analog sequential shifter.

[0004] The present disclosure provides an electric vehicle in which a driver can select a mode in which the operation of a manual transmission internal combustion engine vehicle can be experienced and the ease of driving in the mode can be improved in an electric vehicle capable of reproducing the shifting operation of a manual transmission internal combustion engine vehicle.

[0005] According to one aspect of the present disclosure, an electric vehicle has an electric motor as a drive source. The electric vehicle includes an accelerator pedal used in driving the electric vehicle, an analog sequential shifter, and a processor that controls the electric vehicle according to an operation of the accelerator pedal. The analog sequential shifter simulates a sequential shifter used in a shifting operation of a manual transmission internal combustion engine vehicle and is provided in a steering gear. The processor is configured to execute a control mode according to a driver's selection, the control mode associating an operation of the analog sequential shifter with a virtual gear as a virtual gear, and associating an opening degree of the accelerator pedal, the virtual gear, and a vehicle speed of the electric vehicle with a torque of the electric motor. The processor is configured to automatically downshift the virtual gear according to the vehicle speed when the steering angle of the steering wheel becomes a predetermined angle or more during the execution of the control mode.

[0006] According to one aspect of the present disclosure, the analog sequential shifter may be provided on the steering wheel. Alternatively, the analog sequential shifter may be provided on the steering column.

[0007] Moreover, according to other aspects of the present disclosure, a program controls an electric vehicle. The electric vehicle has an electric motor as a drive source, and includes an accelerator pedal used during driving of the electric vehicle, a simulated sequential shifter, and a processor that controls the electric vehicle according to an operation of the accelerator pedal. The simulated sequential shifter simulates a sequential shifter used in a shifting operation of a manual transmission internal combustion engine vehicle and is provided on a steering wheel. The program causes the processor to execute: executing a control mode according to a driver's selection, the control mode associating an operation of the simulated sequential shifter with a virtual gear as a virtual gear position, and associating an opening degree of the accelerator pedal, the virtual gear position, and a vehicle speed of the electric vehicle with a torque of the electric motor; and during execution of the control mode, when a steering angle of the steering wheel becomes a predetermined angle or more, automatically downshifting the virtual gear according to the vehicle speed.

[0008] In the electric vehicle according to the present disclosure, when the steering angle of the steering wheel becomes a predetermined angle or more in a manual mode, the virtual gear is automatically downshifted according to the vehicle speed of the electric vehicle. That is, even when the steering angle of the steering wheel becomes large and it is difficult for the driver to operate the simulated sequential shifter, downshifting corresponding to the vehicle speed is automatically performed. As a result, downshifting can be performed without waiting until the steering angle of the steering wheel becomes small and it becomes easy for the driver to operate the simulated sequential shifter, and smooth acceleration when the driver desires to accelerate the electric vehicle again can be achieved. In this way, driving performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the drawings, in which like reference numerals denote like elements, and in which:

[0010] Figure 1 is a diagram showing the structure of an electric vehicle according to an embodiment of the present disclosure.

[0011] Figure 2 is a diagram showing an example of a simulated sequential shifter provided on a steering wheel.

[0012] Figure 3 is a diagram showing an example of a simulated sequential shifter provided on a steering column.

[0013] Figure 4 is a tree diagram showing an example of a control mode of an electric vehicle that can be selected in a control device.

[0014] Figure 5 is a diagram showing the structure of a control device related to driving control of an electric vehicle.

[0015] Figure 6This is a diagram showing the structure of a control device related to the sound control of an electric vehicle.

[0016] Figure 7 This is a conceptual diagram showing an example of a scenario for performing automatic upshifting of an electric vehicle according to the present embodiment.

[0017] Figure 8 This is a flowchart showing an example of processing performed by the electric vehicle according to the present embodiment.

[0018] Figure 9 This is a diagram showing the state of rotation of the steering wheel when an analog sequential shifter is provided on the steering column.

[0019] Figure 10 This is a graph for explaining the timing of performing automatic downshifting of an electric vehicle according to the present embodiment. Detailed Embodiments

[0020] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0021] 1. Structure of the powertrain of an electric vehicle

[0022] Figure 1 This is a diagram schematically showing the structure of an electric vehicle 100 according to an embodiment of the present disclosure. First, refer to Figure 1 to describe the structure of the powertrain of the electric vehicle 100.

[0023] The electric vehicle 100 is provided with two electric motors (M) 4F and 4R at the front and rear as a power source for driving. The electric motors 4F and 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 left and right independent electronically controlled front suspensions 7F. The rear wheels 6R are suspended by left and right independent electronically controlled rear suspensions 7R.

[0024] Inverters (INV) 3F and 3R are respectively installed on the front electric motor 4F and the rear electric motor 4R. The front inverter 3F and the rear inverter 3R are respectively connected to a battery (BATT) 2. The battery 2 stores electrical energy for driving the electric motors 4F and 4R. That is, the electric vehicle 100 is a battery electric vehicle (BEV) that travels using the 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 through PWM control.

[0025] 2. Structure of the control system of an electric vehicle

[0026] Next, refer to Figures 1 to 3And explain the structure of the control system of the electric vehicle 100.

[0027] 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.

[0028] The electric vehicle 100 is equipped with a vehicle speed sensor 11. At least one of the wheel speed sensors (not shown) respectively provided on the left and right front wheels 6F and the left and right rear wheels 6R is used as the vehicle speed sensor 11. And, the electric vehicle 100 is equipped with an accelerator pedal stroke sensor 12. The accelerator pedal stroke sensor 12 is provided on the accelerator pedal 22 and outputs a signal indicating the depression amount of the accelerator pedal 22, that is, the accelerator opening. And, the electric vehicle 100 is equipped with a brake pedal stroke sensor 13. The brake pedal stroke sensor 13 is provided on the brake pedal 23 and outputs a signal indicating the depression amount of the brake pedal 23, that is, the brake opening. Moreover, the electric vehicle 100 is equipped with a steering angle sensor 14. The steering angle sensor 14 is provided on the steering gear 24 and outputs a signal indicating the steering angle of the steering gear 24, that is, the rotation angle of the steering wheel.

[0029] The accelerator pedal 22, the brake pedal 23, and the steering gear 24 are driving operation components used during the driving of the electric vehicle 100. In addition to those driving operation components, the electric vehicle 100 is equipped with an analog shift operation component that simulates the operation components used in the shift operation of a manual transmission internal combustion locomotive. The analog shift operation component at least includes the following analog sequential shifter 25.

[0030] In the present embodiment, the analog sequential shifter 25 is provided on the steering gear 24. Figure 2 And Figure 3 An example of the analog sequential shifter 25 is shown in

[0031] In Figure 2 As an example of the analog sequential shifter 25, an analog paddle shifter 51 mounted on the steering wheel 41 is shown. The analog paddle shifter 51 is a dummy different from the original steering wheel-fixed paddle shifter which is a type of sequential shifter. The analog paddle shifter 51 is composed of a pair of paddles having a structure similar to the shift paddles mounted on the steering wheel. It is configured to be able to move the left and right paddles independently. Since the analog paddle shifter 51 is fixed to the steering wheel 41, when the steering wheel 41 rotates, the analog paddle shifter 51 also rotates together with the steering wheel 41.

[0032] A shift switch 15 is provided on the analog paddle shifter 51 (refer to Figure 1). The shift switch 15 outputs an upshift signal when the right paddle is pulled and a downshift signal when the left paddle is pulled. Alternatively, the left paddle may correspond to the upshift signal and the right paddle may correspond to the downshift signal. However, since the electric vehicle 100 does not have a physical transmission, the gears that increase or decrease according to the signal from the shift switch 15 are virtual gears.

[0033] In Figure 3 As an example of the analog sequential shifter 25, an analog paddle shifter 52 mounted on the steering column (steering shaft) 42 is shown. The analog paddle shifter 52 is a substitute different from the original steering column-fixed paddle shifter. The analog paddle shifter 52 is composed of a pair of paddles having a structure similar to the shift paddles mounted on the steering column. It is configured to be able to move the left and right paddles independently. Since the analog paddle shifter 52 is fixed to the steering column 42, the position of the analog paddle shifter 52 does not change even when the steering wheel 41 rotates.

[0034] A shift switch 15 is provided in the analog paddle shifter 52 (see Figure 1 ). An upshift signal is output from the shift switch 15 when the right paddle is pulled, and a downshift signal is output from the shift switch 15 when the left paddle is pulled. Alternatively, the left paddle may correspond to the upshift signal and the right paddle may correspond to the downshift signal.

[0035] As another example, the analog sequential shifter 25 may also be buttons provided on the steering wheel 41. For example, one button is provided on each of the left and right sides of the steering wheel 41. When the right button is pressed, the shift switch 15 outputs an upshift signal, and when the left button is pressed, the shift switch 15 outputs a downshift signal.

[0036] Referring again to Figure 1 . The electric vehicle 100 includes a human-machine interface (HMI) 20 as an interface with the driver and an in-vehicle speaker 21. The HMI 20 includes a touch panel display. The HMI 20 displays information on the touch panel display and accepts input from the driver based on a touch operation on the touch panel display. The in-vehicle speaker 21 provides information to the driver by sound and is capable of outputting the simulated engine sound described later.

[0037] The electric vehicle 100 includes a control device 101. The sensors mounted on the electric vehicle 100 and the devices to be controlled are connected to the control device 101 via an in-vehicle network. In addition to the battery management system 10, the vehicle speed sensor 11, the accelerator pedal stroke sensor 12, the brake pedal stroke sensor 13, the steering angle sensor 14, and the shift switch 15, various sensors are also mounted in the electric vehicle 100.

[0038] Typically, the control device 101 is an electronic control unit (ECU). The control device 101 can also be a combination of multiple ECUs. The control device 101 at least includes a processor 102 and a memory 103. The memory 103 includes a RAM for temporarily recording data, a ROM for storing a program 104 executable by the processor 102, and various data 105 related to the program. The program 104 consists of multiple instructions. The processor 102 reads out the program 104 and data 105 from the memory 103 and executes them, and generates a control signal based on the signals obtained from each sensor. The number of processors 102 included in the control device 101 can be one or multiple.

[0039] The control modes in which the control device 101 controls the electric vehicle 100 include multiple modes, at least including an automatic mode and a manual mode. The control mode can be selected by the driver himself / herself through a touch operation on the touch panel display of the HMI 20. Specifically, by performing a touch operation on the touch panel display of the HMI 20, one or more programs 104 associated with each touch operation are read out from the memory 103 and executed by the processor 102. Hereinafter, the control modes of the electric vehicle 100 based on the control device 101 that the driver can select through the operation of the HMI 20, and the driving control and sound control of the electric vehicle 100 related to the control modes will be described.

[0040] 3. Control Modes of Electric Vehicles

[0041] Figure 4 It is a tree diagram showing an example of the control modes of the electric vehicle 100 that can be selected in the control device 101. In the HMI 20, a selection screen is displayed on the touch panel display according to the Figure 4 shown control tree.

[0042] On the initial screen of the HMI 20, the option "Control Mode" OP100 is displayed. By selecting the option "Control Mode" OP100, the options "Automatic Mode" OP110 and "Manual Mode" OP120 are displayed on the touch panel display. When the option "Automatic Mode" OP110 is selected, the control mode of the electric vehicle 100 is switched to the automatic mode. The automatic mode is a control mode for driving the electric vehicle 100 as a normal BEV. In the automatic mode, the driver can basically drive the electric vehicle 100 only by operating the accelerator pedal 22, the brake pedal 23, and the steering wheel 41. In the automatic mode, the shifting operation of the simulated sequential shifter 25 is invalidated.

[0043] When the option "manual mode" OP120 is selected, the control mode of the electric vehicle 100 is switched to the manual mode. The manual mode refers to a control mode for operating the electric vehicle 100 in the same way as a manually shifted internal combustion locomotive. In the manual mode, the driver uses the analog sequential shifter 25 to perform the shifting operation. Moreover, the operation when the gear ratio of the manual transmission is switched is reproduced by the shifting operation of the analog sequential shifter 25. It should be noted that the clutch operation in a true sequential shift type manual transmission is automatically performed by a robot. Therefore, in the manual mode of the electric vehicle 100, the clutch opening is also automatically calculated. It should be noted that the electric vehicle 100 does not have a physical clutch, so the calculated clutch opening in the manual mode is a virtual clutch opening.

[0044] The manual mode may further include multiple control modes. The control modes that the driver can select may include, for example, control modes related to drive modes such as four-wheel drive and rear-wheel drive, and control modes related to the type of engine sound reproduced in the electric vehicle 100.

[0045] 4. Driving Control of Electric Vehicle

[0046] Figure 5 FIG. is a diagram showing the structure of the control device 101 related to the driving control of the electric vehicle 100. Specifically, the structure particularly related to torque control in the driving control is shown. One or more driving control programs 104 stored in the memory 103 are executed by the processor 102, whereby the processor 102 functions as a driving control device.

[0047] A control mode signal is input from the HMI 20 to the control device 101 as a driving control device. The control mode signal contains information related to the control mode selected by the driver. The control device 101 performs the process P110 based on the control mode signal. In the process P110, the control mode is switched according to the control mode signal. The switching between the automatic mode and the manual mode particularly affects the driving control during the switching of the control mode.

[0048] When the control mode is switched to the automatic mode, the control device 101 performs the process P120 for torque calculation in the automatic mode. In the process P120, the control device 101 obtains the vehicle speed from the signal of the vehicle speed sensor 11 and the accelerator opening from the signal of the accelerator pedal stroke sensor 12. The control device 101 has a motor torque map with the accelerator opening and the vehicle speed as parameters. The control device 101 inputs the vehicle speed and the accelerator opening into the motor torque map, and controls the converters 3F, 3R so that the motors 4F, 4R generate the torque obtained by using the motor torque map.

[0049] When the control mode is switched to the manual mode, the control device 101 executes the process P130 for torque calculation in the manual mode. The process P130 includes the process P131 for calculating the torque generated in the drive wheels. Also, the process P130 includes the processes P132 and P133. The process P132 is the process for calculating the torque generated by the front motor 4F, and the process P133 is the process for calculating the torque generated by the rear motor 4R. The processes P132 and P133 are executed in accordance with the drive wheel torque calculated in the process P130 and the torque distribution between the front wheels 6F and the rear wheels 6R.

[0050] The vehicle model MOD01 is used in the calculation of the drive wheel torque in the process P131. The vehicle model MOD01 includes the engine model MOD11, the clutch model MOD12, and the transmission model MOD13. The engine virtually realized by the vehicle model MOD01 is called the virtual engine. The clutch virtually realized is called the virtual clutch. The transmission virtually realized is called the virtual transmission. The virtual engine is modeled in the engine model MOD11. The virtual clutch is modeled in the clutch model MOD12. The virtual transmission is modeled in the transmission model MOD13.

[0051] The engine model MOD11 calculates the virtual engine speed and the virtual engine torque. The virtual engine speed is calculated based on the vehicle speed, the overall reduction ratio, and the slip ratio of the virtual clutch. The virtual engine torque is calculated based on the virtual engine speed and the accelerator opening. The vehicle speed is obtained from the signal of the vehicle speed sensor 11. The accelerator opening is obtained from the signal of 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 can also be selected by the driver through the operation of the HMI 20. For example, the engine characteristics can be selected from a low-medium rotation type, a high rotation type, and a full range type.

[0052] The clutch model MOD12 calculates the torque transmission gain. The torque transmission gain is a gain for calculating the torque transmission degree of the virtual clutch. In the clutch model MOD12, the torque transmission gain is given with respect to the clutch opening. The clutch opening is calculated using the clutch operation model. The clutch operation model is a model that simulates the clutch operation of a model driver. The vehicle speed, the virtual engine speed, and the signal from the shift switch 15 are input to the clutch operation model.

[0053] The signal from the shift switch 15 is used to measure the timing of clutch operation. When the driver's shift operation is detected by the signal from the shift switch 15, in the clutch operation model, the clutch opening is maximized by disconnecting the virtual clutch. The vehicle speed and the virtual engine speed are used for the calculation of the clutch opening. In order to smoothly match the rotational speed of the input shaft of the virtual transmission calculated from the vehicle speed and the virtual engine speed, in the clutch operation model, the clutch opening is calculated based on the rotational speed difference between the input shaft of the virtual transmission and the virtual engine speed.

[0054] The torque transfer gain calculated in the clutch model MOD12 is converted into the clutch torque capacity of the virtual clutch, that is, the virtual clutch torque capacity. And, based on the comparison between the virtual clutch torque capacity and the virtual engine torque calculated in the engine model MOD11, the virtual clutch torque input from the virtual clutch to the virtual transmission is calculated. And, in the clutch model MOD12, the value obtained by subtracting the torque transfer gain from 1 is calculated as the slip ratio. The slip ratio is used for the calculation of the virtual engine speed in the engine model MOD11.

[0055] The transmission model MOD13 calculates the virtual gear ratio. The virtual gear ratio is the gear ratio determined by the virtual gear in the virtual transmission. The virtual gear ratio is set for each virtual gear. The maximum virtual gear ratio is set in the first gear, and the virtual gear ratio is made smaller in the order of the second gear, the third gear, the fourth gear,.... The virtual gear rises one level when receiving the upshift signal from the shift switch 15, and drops one level when receiving the downshift signal from the shift switch 15. It should be noted that the number of gears determined by the simulated sequential shifter 25 has no physical limit. Therefore, for example, the driver can also arbitrarily set the number of gears through the HMI20.

[0056] The transmission model MOD13 uses the virtual gear ratio and the virtual clutch torque to calculate the virtual transmission torque. The virtual transmission torque is the virtual torque output from the virtual transmission. The control device 101 controls the converters 3F, 3R in such a way that the output torques of the motors 4F, 4R change 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 causes a torque shock in the electric vehicle 100, simulating the characteristics of a vehicle equipped with a stepped transmission.

[0057] The vehicle model MOD01 calculates the driving wheel torque based on the virtual transmission torque and the reduction ratio. The torque distribution between the front wheels 6F and the rear wheels 6R can be fixed or variable by controlling the motors 4F and 4R through the converters 3F and 3R. When the four-wheel drive mode is selected as the driving mode, the driving 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 to the front wheels 6F and the rear wheels 6R can be fixed or actively or passively changed. When the rear-wheel drive mode is selected as the driving mode, the driving wheel torque is the sum of the torques acting on the left and right rear wheels 6R.

[0058] In process P132, the torque of the front motor 4F (front motor torque) in the manual mode is calculated by multiplying the driving wheel torque calculated in process P131 by the torque distribution ratio to the front wheels 6F and the reduction ratio from the output shaft of the front motor 4F to the front wheels 6F. The control device 101 controls the front converter 3F so that the front motor 4F generates the front motor torque calculated in process P132.

[0059] In process P133, the torque of the rear motor 4R (rear motor torque) in the manual mode is calculated by multiplying the driving wheel torque calculated in process P131 by the torque distribution ratio to the rear wheels 6R and the reduction ratio from the output shaft of the rear motor 4R to the rear wheels 6R. The control device 101 controls the rear converter 3R so that the rear motor 4R generates the rear motor torque calculated in process P133.

[0060] It should be noted that in Figure 5 the structure shown, the battery management system 10 and the brake pedal stroke sensor 13 are not necessarily required in the above driving control. However, when the switching of the control mode affects the SOC of the battery 2, the signal of the battery management system 10 can be used as information for determining whether the control mode can be switched. Also, in a situation where the operation method of the electric vehicle 100 changes greatly, such as the switching between the automatic mode and the manual mode, stepping on the brake pedal 23 can also be used as a switching condition. In this case, the signal of the brake pedal stroke sensor 13 can be used as information for determining that the brake pedal 23 has been stepped on.

[0061] 5. Sound control of electric vehicles

[0062] Figure 6FIG. 0 is a diagram showing the structure of a control device 101 related to the sound control of an electric vehicle 100. One or more programs 104 for sound control stored in a memory 103 are executed by a processor 102, whereby the processor 102 functions as a sound control device. The processor 102 functioning as a torque control device and the processor 102 functioning as a sound control device may be separate processors or the same processor.

[0063] The control device 101 as a sound control device can cause an artificially generated sound to be produced from an in-vehicle speaker 21. One of the artificial sounds is an analog engine sound similar to the engine sound in an existing internal combustion locomotive. When a control mode signal indicating the selection of a manual mode is input from an HMI 20, the control device 101 as a sound control device executes process P140. In process P140, an analog engine sound is generated based on the virtual engine torque and virtual engine speed calculated in process P131.

[0064] In process P140, a specified engine sound is used as the sound source of the analog engine sound produced from the in-vehicle speaker 21. The type of engine sound can be selected by the driver in the HMI 20, for example. However, in process P140, the sound of the sound source is not directly used. In process P140, 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.

[0065] Process P140 includes a process P141 for calculating the engine sound pressure and a process P142 for calculating the engine sound frequency. In process P141, using a sound pressure map M11, the sound pressure of the analog engine sound is calculated based on the virtual engine torque. The sound pressure map M11 is made such that the greater the virtual engine torque, the greater the sound pressure. In process P142, using a frequency map M12, the frequency of the analog engine sound is calculated based on the virtual engine speed. The frequency map M12 is made such that the greater the virtual engine speed, the higher the frequency. The virtual engine torque and virtual engine speed change according to the driver's accelerator operation, shift operation, and clutch operation. By changing the sound pressure and frequency of the analog engine sound according to the thus-changed virtual engine torque and virtual engine speed, a sense of reality similar to driving a real manual transmission internal combustion locomotive can be given to the driver.

[0066] 6. First Embodiment - Analog Sequential Shifter Provided on the Steering Wheel

[0067] 6-1. Automatic Downshifting during Steering

[0068] As described above, the driver of the electric vehicle 100 can experience the operation of a manual transmission internal combustion engine in the electric vehicle 100 by operating the HMI 20 and switching the control mode to the manual mode. Although simply simulating the operation feeling of a manual transmission internal combustion engine can provide sufficient fun for the driver, it is also considered to enable the driver to experience the operation of a manual transmission internal combustion engine and further improve convenience on this basis.

[0069] As one of the scenarios where the driver may feel inconvenient, as Figure 7 shown, consider the scenario where the electric vehicle 100 is traveling on a road surface with continuous curves such as a mountain road. It should be noted that in the first embodiment, it is considered that the simulated sequential shifter 25 is the simulated paddle shifter 51 provided on the steering wheel 41.

[0070] Set the electric vehicle 100 to enter a curve at a relatively high speed while maintaining travel on the straight section before the curve. At the moment of entering the curve, according to the vehicle speed, the virtual gear is placed on the high gear side, for example, the fifth gear or the sixth gear. And it is set that after entering the curve, the driver reduces the vehicle speed of the electric vehicle 100. Since the vehicle speed decreases, the virtual engine speed also decreases.

[0071] Considering that when accelerating again on the straight road surface after exiting the curve, it is preferable for the driver to pre-reduce the virtual gear according to the virtual engine speed. If the driver of a manual transmission internal combustion engine, usually judges to what extent the engine speed has become low based on the magnitude of the engine sound, etc., and when the engine speed has become low to a certain extent, downshifts in a way that becomes a gear matching the engine speed and the vehicle speed. For the electric vehicle 100 that simulates the operation of a manual transmission internal combustion engine, the driver's operation is basically the same. That is, since the vehicle speed decreases and the virtual engine speed gradually decreases, the simulated engine sound becomes smaller. And the driver should judge based on the magnitude of the simulated engine sound, the vehicle speed, etc., and consider downshifting the virtual gear when the virtual engine speed has decreased to a certain extent.

[0072] However, at this time, the driver is turning the steering wheel 41 according to the curve of the road surface. And due to turning the steering wheel 41, the simulated paddle shifter 51 also rotates together and its position changes.

[0073] Figure 7The rotation of the steering wheel 41 is shown. When the steering wheel 41 is turned and the rotation angle of the steering wheel 41 becomes large up to around 180° as in the lowermost state, the left and right of the simulated paddle shifters 51 become opposite. The paddle on the left side as viewed from the driver corresponds to upshifting and the paddle on the right side corresponds to downshifting. Therefore, the driver may be confused as to which paddle corresponds to downshifting and may find it difficult to operate. Also, when the rotation angle becomes large, the driver may change hands to hold the steering wheel 41. In this case, confusion is more likely to occur. It may also be difficult to operate due to the change of hands.

[0074] Thus, although it is desired to downshift after entering a curve, the position of the simulated paddle shifters 51 changes, so the driver may not be able to perform the intended operation. In such a scenario, although it is possible to continue driving without downshifting, if downshifting is performed before exiting the curve, the acceleration after exiting the curve is smoother. Therefore, in the electric vehicle 100 according to the present embodiment, during manual mode driving, when the virtual engine speed becomes below a prescribed speed in a state where the steering angle of the steering gear 24 is large, the virtual gear is automatically downshifted according to the virtual engine speed. It should be noted that the steering angle of the steering gear 24 may also be referred to as the rotation angle of the steering wheel 41.

[0075] Figure 8 It is a flowchart showing an example of the processing executed by the electric vehicle 100. Figure 8 The processing shown in the flowchart is implemented by the processor 102 executing one or more driving control programs 104 stored in the memory 103.

[0076] According to Figure 8 the flow shown, first in step S101, it is determined whether the manual mode is selected as the control mode. If the manual mode is not selected, the process ends.

[0077] When the manual mode is selected as the control mode, step S102 is executed. In step S102, it is determined whether the rotation angle of the steering wheel 41 is equal to or greater than a prescribed angle. The prescribed angle here is set in advance. If the rotation angle of the steering wheel is less than the prescribed angle, the process ends.

[0078] When the rotation angle of the steering wheel 41 is greater than or equal to a specified angle, step S103 is executed. In step S103, it is determined whether the virtual engine speed is less than or equal to a specified speed. In step S103, the processor 102 may determine that the virtual engine speed is less than or equal to the specified speed when the state where the virtual engine speed is less than or equal to the specified speed has continued for a certain period of time or more, and determine that the virtual engine speed is higher than the specified speed when the state where the virtual engine speed is less than or equal to the specified speed ends before a certain period of time has elapsed. When the virtual engine speed is higher than the specified speed, the process ends.

[0079] When the virtual engine speed is less than or equal to the specified speed, step S104 is executed. In step S104, the virtual gear is downshifted from the current gear to the next lower gear.

[0080] 6-2. Effect

[0081] According to the above processing, when the virtual engine speed decreases in a state where the steering gear 24 is turned significantly during the running of the electric vehicle 100, automatic downshifting corresponding to the virtual engine speed is performed. The state where the steering gear 24 is turned significantly is generated when the electric vehicle 100 travels around a bend or a corner. In this state, it is difficult for the driver to grasp the position of the paddle corresponding to the downshift. However, since the downshift is automatically performed according to the virtual engine speed, smooth acceleration after passing through the bend or the corner becomes possible. In this way, the convenience for the driver can be improved.

[0082] It should be noted that when the driver directly stops the electric vehicle 100 at a bend or the like and there is no assumption of restarting the acceleration of the electric vehicle 100, downshifting is not necessarily required. However, even in this case, downshifting will not have an adverse effect on the running of the electric vehicle 100, so the above processing will not be an obstacle to the driver.

[0083] 6-3. Specified angle

[0084] The specified angle used as the determination criterion in step S102 is set to an angle close to 180°. When the rotation angle of the steering wheel 41 approaches 180°, the left and right of the simulated paddle shifter 51 become opposite. For the driver, it becomes difficult to grasp the position of the paddle. However, the specified angle can also be set to 150°, for example, or can also be set to 120°. Furthermore, it is also possible to use 90° where the positions of the left and right paddles are opposite to each other with respect to the plumb line passing through the center of the steering wheel 41 as a reference, and determine that the determination in step S102 is established if the rotation angle of the steering wheel 41 is 90° or more.

[0085] 7. Second Embodiment - Simulated Paddle Shifter Provided on the Steering Column

[0086] The second embodiment is an embodiment in which the analog sequential shifter 25 is an analog paddle shifter 52 provided on the steering column 42. Similar to the first embodiment, consider a scenario where the virtual engine speed decreases as the driver reduces the amount of depression of the accelerator pedal 22 while the electric vehicle 100 is traveling on a curved road surface. In the second embodiment, there may also arise a problem that downshifting cannot be smoothly performed in a scenario where the driver desires to downshift.

[0087] Figure 9 The state when the steering wheel 41 rotates is shown. The gray area surrounded by the dashed line is the position where the left hand is placed when the steering wheel 41 is in the initial position. Since it is fixed to the steering column 42, the position of the analog paddle shifter 52 itself does not change, but as the steering wheel 41 rotates, the positional relationship with the position of the hand changes. For the driver, it becomes difficult to operate the analog paddle shifter 52. For example, when the rotation angle of the steering wheel 41 is around 90°, the position of the left hand moves away from the position of the left paddle of the analog paddle shifter 52, making it difficult to perform a downshifting operation. When the rotation angle becomes even larger, the position of the left hand and the position of the left paddle of the analog paddle shifter 52 become even farther apart. When the rotation angle becomes large, the driver may change hands to hold the steering wheel 41. Even if the hands are changed, the positional relationship between the position of the hand and the analog paddle shifter 52 is different from when the steering wheel 41 is in the initial position, so it may become difficult to operate the analog paddle shifter 52. Therefore, in the second embodiment, when the electric vehicle 100 selects the manual mode and the steering angle of the steering gear 24 becomes larger than a specified angle during traveling, the virtual gear is automatically downshifted according to the virtual engine speed.

[0088] The processing performed by the electric vehicle 100 can be represented by the Figure 8 flowchart as in the first embodiment. Regarding the processing performed in steps S101 to S104, it is the same as in the first embodiment. However, the specified angle used for determination in step S102 is set to an angle smaller than that in the first embodiment. This is because in the second embodiment, before the rotation angle of the steering wheel 41 reaches 90°, the position of the left hand moves away from the position of the left paddle of the analog paddle shifter 52, creating a difficulty for the driver to perform an operation for downshifting. The specified angle can also be, for example, 80°.

[0089] Through this processing of the electric vehicle 100, even in a scenario where it becomes difficult for the driver to operate the simulated paddle shifter 52 due to an increase in the steering angle of the steering gear 24, an automatic downshift corresponding to the virtual engine speed is performed. The state where the steering angle of the steering gear 24 increases occurs during the driving of the electric vehicle 100 at a corner, a bend, etc., and enables smooth acceleration after passing through the corner or bend. Thus, the convenience for the driver can be improved.

[0090] 8. Timing of downshift

[0091] As described above, the automatic downshift based on the virtual engine speed performed by the electric vehicle 100 has been explained. It should be noted that the timing of performing the automatic downshift can also be said to be determined according to the vehicle speed. Figure 10 The relationship between the vehicle speed and the virtual engine speed of the electric vehicle 100 is shown. And, the circle shown by the dotted line represents the switching timing of the virtual gear during the automatic downshift. It should be noted that in Figure 10 the virtual gear has five levels from the first gear to the fifth gear, but the number of gear levels is an example. As Figure 10 shown, if there is no operation of the simulated sequential shifter 25 and the clutch opening is constant, the vehicle speed and the virtual engine speed at a certain gear are in a one-to-one correspondence relationship. Therefore, the timing of the downshift determined by the virtual engine speed can also be said to be determined by the vehicle speed corresponding to the gear.

[0092] 9. Notification to the driver

[0093] The automatic downshift performed based on the electric vehicle 100 can also be notified to the driver through the HMI 20. For example, the current gear can be displayed on the display of the HMI 20, and the driver can observe the display and be able to know that the gear has been switched.

[0094] Or, the automatic downshift can be not explicitly notified to the driver. When the virtual gear is switched by the downshift, since the virtual engine torque increases, the engine sound suddenly becomes louder. Therefore, even without notification based on display or the like, the driver can be aware of the automatic downshift.

Claims

1. An electric vehicle having an electric motor as a driving source, comprising: an accelerator pedal for driving the electric vehicle; A simulated sequential shifter, which is arranged on the steering gear and simulates the sequential shifter used in the speed change operation of a manual transmission type internal combustion locomotive; as well as A processor controls the electric vehicle according to the operation of the accelerator pedal, wherein: The processor is configured to execute the following control mode according to the driver's selection: the operation of the simulated sequential shifter is associated with a virtual gear position as a virtual gear position, and the opening degree of the accelerator pedal, the virtual gear position, and the speed of the electric vehicle are associated with the torque of the motor, and The processor is configured to automatically downshift the virtual gear according to the vehicle speed when a steering angle of a steering wheel becomes equal to or larger than a predetermined angle during execution of the control mode.

2. The electric vehicle according to claim 1, wherein: The simulated sequential gear shifter is arranged on the steering wheel.

3. The electric vehicle according to claim 1, wherein: The simulated sequential gear shifter is arranged on the steering column.

4. The electric vehicle according to claim 2, wherein: The simulated sequential shifter is a button disposed on the steering wheel.

5. The electric vehicle according to claim 2 or 3, wherein: The simulated sequential shifter is a simulated paddle shifter that simulates a paddle shifter.

6. The electric vehicle according to claim 5, wherein: The simulated paddle shifter is a pair of paddles installed on the left and right sides of the steering gear.

7. The electric vehicle according to any one of claims 1 to 4, wherein: Upon receiving that the vehicle speed has dropped below the vehicle speed set for each of the virtual gears, the virtual gear is automatically downshifted according to the vehicle speed.

8. The electric vehicle according to any one of claims 1 to 4, wherein: The electric vehicle further includes a speaker for outputting a simulated engine sound that reproduces the engine sound of the manual transmission type internal combustion engine vehicle into the vehicle. The processor is configured to further execute, during the execution of the control mode: playing the simulated engine sound from the speaker; and The opening degree of the accelerator pedal, the virtual gear position, and the vehicle speed are associated with the magnitude of the simulated engine sound.

9. The electric vehicle according to any one of claims 1 to 4, wherein: Automatically downshifting the virtual gear position according to the vehicle speed includes changing the virtual gear position from a current gear position to a gear position of a next step according to the vehicle speed.

10. A program for controlling an electric vehicle, the electric vehicle having an electric motor as a driving source, the electric vehicle comprising: an accelerator pedal for driving the electric vehicle; a simulated sequential shifter provided on a steering gear and simulating a sequential shifter used in a shifting operation of a manual transmission type internal combustion engine vehicle; and a processor for controlling the electric vehicle according to the operation of the accelerator pedal, wherein: The program causes the processor to execute: The following control mode is executed according to the driver's selection: the operation of the simulated sequential shifter is associated with a virtual gear position as a virtual gear position, and the opening degree of the accelerator pedal, the virtual gear position, and the speed of the electric vehicle are associated with the torque of the motor; and During execution of the control mode, when the steering angle of the steering wheel becomes equal to or larger than a predetermined angle, the virtual gear position is automatically downshifted according to the vehicle speed.

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