Electric vehicle and program for controlling electric vehicle

Abstract

The present disclosure provides an electric vehicle capable of reproducing a gear shift operation of a manual transmission type internal-combustion engine vehicle. The electric vehicle comprises an accelerator pedal and a pseudo-sequential shifter. The pseudo-sequential shifter simulates a sequential shifter used for the gear shift operation of a manual transmission type internal-combustion engine vehicle. The electric vehicle executes a manual mode in response to a selection by a driver. In the manual mode, the operation of the pseudo-sequential shifter is associated with a virtual shift position, which is a shift position that is virtual. Also, in the manual mode, the opening degree of an accelerator pedal, the virtual shift position, and the vehicle speed of the electric vehicle are associated with the torque of an electric motor. The electric vehicle automatically upshifts the virtual shift position in accordance with the vehicle speed of the electric vehicle when the steering angle of a steering wheel becomes a predetermined angle or more during the execution of the manual mode.

Description

Electric vehicles and programs for controlling electric vehicles

[0001] The present disclosure relates to a technique for controlling an electric vehicle that has an electric motor as a drive source.

[0002] Japanese Patent Application Laid-Open Publication No. 2021-151168 discloses a conventional technology related to an electric vehicle that can simulate the manual shifting operation of a vehicle equipped with a manual transmission powered by an internal combustion engine (hereinafter referred to as a manual-shift internal combustion engine vehicle) by controlling an electric motor. The driver of the electric vehicle can select multiple virtual gear modes (virtual shift positions) using paddle switches or the like. The paddle switches are a shift device (hereinafter referred to as a pseudo-sequential shifter) that simulates a sequential shifter provided on the steering wheel.

[0003] Japanese Patent Application Laid-Open No. 2021-151168

[0004] According to the above-described conventional technology, it is possible to experience the gear shifting operation of a manual-transmission internal combustion engine vehicle in an electric vehicle. The driver can then select a virtual shift position that replicates the shift position of a manual-transmission internal combustion engine vehicle using a pseudo-sequential shifter. However, when the pseudo-sequential shifter is provided on the steering wheel, the positional relationship between the hands on the steering wheel and the pseudo-sequential shifter changes when the steering wheel is turned significantly to turn the electric vehicle. As a result, it becomes difficult for the driver to smoothly operate the pseudo-sequential shifter when the steering angle is large.

[0005] The present disclosure has been made in view of the above-mentioned problems, and it is an object of the present disclosure to provide an electric vehicle that is capable of reproducing the gear shifting operation of a manual transmission internal combustion engine vehicle, allows the driver to select a mode in which the driver can experience the operation of a manual transmission internal combustion engine vehicle, and improves the ease of driving in that mode.

[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-sequential shifter, and a control device that controls the electric vehicle in response to operation of the accelerator pedal. The pseudo-sequential shifter is an operating member attached to a steering wheel that simulates a sequential shifter used for shifting gears in a manually variable internal combustion engine vehicle. The control device is configured to perform the following: First, the control device executes a manual mode, which is one of the control modes, in response to a driver's selection. In the manual mode, operation of the pseudo-sequential shifter is associated with a virtual shift position, which is a virtual shift position. In the manual mode, the accelerator pedal opening, the virtual shift position, and the vehicle speed of the electric vehicle are associated with the torque of the electric motor. Second, while the manual mode is being executed, when the steering angle of the steering wheel is equal to or greater than a predetermined angle, the control device automatically upshifts the virtual shift position in response to the vehicle speed of the electric vehicle.

[0007] According to one aspect of the present disclosure, the pseudo-sequential shifter may be mounted on the steering wheel, or the pseudo-sequential shifter may be mounted on the steering column.

[0008] The present disclosure also provides a program for controlling an electric vehicle. The electric vehicle has an electric motor as a drive source and includes an accelerator pedal used for driving, a pseudo-sequential shifter, and a control device that controls the electric vehicle in response to operation of the accelerator pedal. The pseudo-sequential shifter is an operating member attached to a steering wheel that simulates a sequential shifter used for shifting gears in a manually variable internal combustion engine vehicle. The program causes a computer to perform the following: First, the program executes a manual mode, which is one of the control modes, in response to a driver's selection. In the manual mode, operation of the pseudo-sequential shifter is associated with a virtual shift position, which is a virtual shift position. In the manual mode, the accelerator pedal opening, the virtual shift position, and the vehicle speed of the electric vehicle are associated with the torque of the electric motor. Second, when the steering angle of the steering wheel is equal to or greater than a predetermined angle while the manual mode is being executed, the program automatically upshifts the virtual shift position in response to the vehicle speed of the electric vehicle.

[0009] According to the electric vehicle of the present disclosure, when the steering wheel angle reaches a predetermined angle or more in manual mode, the virtual shift position is automatically upshifted in accordance with the vehicle speed of the electric vehicle. Even when the steering wheel angle becomes large and it becomes difficult to operate the pseudo-sequential shifter, the driver can smoothly upshift at the timing they want to, thereby improving drivability.

[0010] FIG. 1 is a diagram illustrating a configuration of an electric vehicle according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of a pseudo-sequential shifter provided on a steering wheel. FIG. 3 is a diagram illustrating an example of a pseudo-sequential shifter provided on a steering column. FIG. 4 is a tree diagram illustrating an example of control modes of an electric vehicle selectable by a control device. FIG. 5 is a diagram illustrating a configuration of a control device related to driving control of an electric vehicle. FIG. 6 is a diagram illustrating a configuration of a control device related to sound control of an electric vehicle. FIG. 7 is a conceptual diagram illustrating an example of a situation in which an automatic upshift is performed by an electric vehicle according to the present embodiment. FIG. 8 is a flow diagram illustrating an example of processing by an electric vehicle according to the present embodiment. FIG. 9 is a diagram illustrating the rotation of the steering wheel when a pseudo-sequential shifter is provided on a steering column. FIG. 10 is a graph diagram for explaining the timing at which an automatic upshift is performed by an electric vehicle according to the present embodiment.

[0011] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0012] 1. Configuration of the Power System of the Electric Vehicle Fig. 1 is a diagram schematically showing 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. 1.

[0013] 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.

[0014] 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 electric 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 the electric energy stored in the battery 2. The inverters 3F and 3R are, for example, voltage-type inverters that control the torque of the electric motors 4F and 4R by PWM control.

[0015] 2. Configuration of the Control System of the Electric Vehicle Next, the configuration of the control system of the electric vehicle 100 will be described with reference to FIGS.

[0016] 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.

[0017] 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 depression amount 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 depression amount of the brake pedal 23, i.e., the brake opening. The electric vehicle 100 is also equipped with a steering angle sensor 14. The steering angle sensor 14 is provided on the steering wheel 24 and outputs a signal indicating the steering angle of the steering wheel 24, i.e., the rotation angle of the steering wheel.

[0018] The accelerator pedal 22, brake pedal 23, and steering wheel 24 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-speed change operation members that imitate operation members used to change speeds in a manually variable internal combustion engine vehicle. The pseudo-speed change operation members include at least the following pseudo-sequential shifter 25.

[0019] In this embodiment, the pseudo-sequential shifter 25 is provided in the steering 24. An example of the pseudo-sequential shifter 25 is shown in FIGS.

[0020] 2 shows a pseudo paddle shifter 51 attached to the steering wheel 41 as an example of the pseudo sequential shifter 25. The pseudo paddle shifter 51 is a dummy that differs from a genuine paddle shifter that is fixed to the steering wheel, which is a type of sequential shifter. The pseudo paddle shifter 51 consists of a pair of paddles that have a structure similar to shift paddles attached to the steering wheel, and the left and right paddles can be moved independently. Because the pseudo paddle shifter 51 is fixed to the steering wheel 41, when the steering wheel 41 rotates, the pseudo paddle shifter 51 also rotates together with the steering wheel 41.

[0021] The pseudo paddle shifter 51 is provided with a shift switch 15 (see FIG. 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 an upshift signal, and the right paddle may correspond to a downshift signal. However, because the electric vehicle 100 does not have an actual transmission, the shift positions that are shifted up or down by the signal from the shift switch 15 are virtual shift positions.

[0022] 3 shows a pseudo paddle shifter 52 attached to the steering column (steering shaft) 42 as an example of the pseudo sequential shifter 25. The pseudo paddle shifter 52 is a dummy that differs from a real paddle shifter that is fixed to the steering column. The pseudo paddle shifter 52 consists of a pair of paddles that have a structure similar to shift paddles attached to the steering column, and the left and right paddles can be moved independently. Because the pseudo paddle shifter 52 is fixed to the steering column 42, the position of the pseudo paddle shifter 52 does not change even when the steering wheel 41 is rotated.

[0023] The pseudo paddle shifter 52 is provided with a shift switch 15 (see FIG. 1). When the right paddle is pulled, an upshift signal is output from the shift switch 15, and when the left paddle is pulled, a downshift signal is output from the shift switch 15. Alternatively, the left paddle may correspond to an upshift signal, and the right paddle may correspond to a downshift signal.

[0024] As yet another example, the pseudo-sequential shifter 25 may be a button provided on the steering wheel 41. For example, one button is provided on each side of the steering wheel 41, and 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.

[0025] Referring again to Figure 1, the electric vehicle 100 is equipped with a human-machine interface (HMI) 20 as an interface with the driver, and an in-vehicle speaker 21. The HMI 20 is equipped with 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 in-vehicle speaker 21 provides information to the driver by voice and is also capable of outputting a pseudo engine sound, which will be described later.

[0026] 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 steering angle sensor 14, and a shift switch 15, the electric vehicle 100 is also equipped with various other sensors.

[0027] 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 composed 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.

[0028] There are multiple control modes in which the control device 101 controls the electric vehicle 100, including at least an automatic mode and a manual mode. 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, and the driving control and sound control of the electric vehicle 100 related to the control modes.

[0029] 4 is a tree diagram showing an example of control modes of the electric vehicle 100 that can be selected by the control device 101. In the HMI 20, a selection screen is displayed on the touch panel display in accordance with the control tree shown in FIG.

[0030] An option "control mode" OP100 is displayed on the initial screen of the HMI 20. By selecting the option "control mode" OP100, an option "automatic mode" OP110 and an option "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 switches to automatic mode. Automatic mode is a control mode for driving the electric vehicle 100 as a normal BEV. In automatic 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 41. In automatic mode, the shift operation of the pseudo-sequential shifter 25 is disabled.

[0031] When the option "manual mode" OP120 is selected, the control mode of the electric vehicle 100 switches to manual mode. Manual mode is a control mode for operating the electric vehicle 100 like a manual transmission internal combustion engine vehicle. In manual mode, the driver performs shifting operations using the pseudo-sequential shifter 25. The operation when the gear ratio of a manual transmission is changed is reproduced by the shifting operation of the pseudo-sequential shifter 25. Note that clutch operation in a real sequential shift type manual transmission is performed automatically by a robot. Therefore, even in manual mode of the electric vehicle 100, the clutch opening degree is calculated automatically. Note that because the electric vehicle 100 does not have an actual clutch, the clutch opening degree calculated in manual mode is a virtual clutch opening degree.

[0032] The manual mode may further include a plurality of control modes. The control modes selectable by the driver may include, for example, a control mode related to a drive mode such as four-wheel drive or rear-wheel drive, and a control mode related to the type of engine sound reproduced by the electric vehicle 100.

[0033] 5 is a diagram showing the configuration of the control device 101 related to the driving control of the electric vehicle 100. In detail, the configuration particularly related to torque control among driving control is shown. 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.

[0034] A control mode signal is input from the HMI 20 to the control device 101, which functions as a cruise 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 cruise control is the switching between automatic mode and manual mode.

[0035] When the control mode is switched to automatic mode, the control device 101 executes process P120 for torque calculation in automatic 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 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 inverters 3F, 3R to cause the electric motors 4F, 4R to generate the torque obtained from the motor torque map.

[0036] When the control mode is switched to the manual mode, the control device 101 executes a process P130 for calculating torque in the manual mode. The process P130 includes a process P131 for calculating the torque to be generated at the drive wheels. The process P130 also includes a process P132 and a process P133. The process P132 is for calculating the torque to be generated at the front electric motor 4F, and the process P133 is for calculating the torque to be generated at the rear electric 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.

[0037] 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 a virtual engine. The clutch model MOD12 models a virtual clutch. The transmission model MOD13 models a virtual transmission.

[0038] 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 pedal position. The vehicle speed is obtained from a signal from the vehicle speed sensor 11. The accelerator pedal position 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 a reduction ratio determined by the mechanical structure from the virtual transmission to the drive wheels. The engine model MOD11 defines a relationship between the virtual engine speed and the virtual engine torque for each accelerator position. The engine characteristics of the engine model MOD11 may be selectable by the driver by operating the HMI 20. For example, the engine characteristics may be selectable from among a low-to-medium rotation type, a high rotation type, and a full-range type.

[0039] The clutch model MOD12 calculates a torque transmission gain. The torque transmission gain is a gain for calculating the degree of torque transmission 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 a clutch operation model. The clutch operation model is a model that simulates the clutch operation of a model driver. The vehicle speed, virtual engine speed, and a signal from the shift switch 15 are input to the clutch operation model.

[0040] The signal from the shift switch 15 is used to determine the timing of clutch operation. When a shift operation by the driver is detected by the signal from the shift switch 15, the clutch opening degree is maximized in the clutch operation model so as to disengage the virtual clutch. The vehicle speed and virtual engine speed are used to calculate the clutch opening degree. In the clutch operation model, the clutch opening degree is calculated based on the rotational speed difference between the rotational speed of the input shaft of the virtual transmission calculated from the vehicle speed and the virtual engine speed so as to smoothly match the rotational speed of the input shaft of the virtual transmission and the virtual engine speed.

[0041] The torque transmission gain calculated by the clutch model MOD12 is converted into the clutch torque capacity of the virtual clutch, i.e., the virtual clutch torque capacity. Then, based on a comparison between the virtual clutch torque capacity and the virtual engine torque calculated by the engine model MOD11, the virtual clutch torque input from the virtual clutch to the virtual transmission is calculated. Furthermore, the clutch model MOD12 calculates a slip ratio by subtracting the torque transmission gain from 1. The slip ratio is used in the calculation of the virtual engine speed by the engine model MOD11.

[0042] The transmission model MOD13 calculates a virtual gear ratio. The virtual gear ratio is a gear ratio in the virtual transmission determined by the virtual shift position. A virtual gear ratio is set for each virtual shift position. The largest 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. The virtual shift position is increased by one step in response to an upshift signal from the shift switch 15, and decreased by one step in response to a downshift signal from the shift switch 15. There is no physical restriction on the number of shift positions determined by the pseudo sequential shifter 25. Therefore, for example, the driver may be able to arbitrarily set the number of shift positions via the HMI 20.

[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 in accordance with the virtual transmission torque. The virtual transmission torque changes discontinuously in response to 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 the drive wheel torque from 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 electric motors 4F and 4R using the inverters 3F and 3R. When four-wheel drive mode is selected as the drive mode, 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. When rear-wheel drive mode is selected as the drive mode, 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 manual 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 to cause the front electric motor 4F to generate the front motor torque calculated in process P132.

[0046] In process P133, the torque of the rear electric motor 4R in the manual 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] 5, 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 automatic mode and manual 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 of Electric Vehicle Figure 6 is a diagram showing the configuration of the control device 101 related to sound control of the electric vehicle 100. The processor 102 executes one or more sound control programs 104 stored in the memory 103, causing the processor 102 to function as a sound control device. 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 speakers 21. One of the artificial sounds is a pseudo-engine sound that resembles the engine sound of a conventional internal combustion engine vehicle. When a control mode signal indicating that the manual mode has been selected is input from the HMI 20, the control device 101 as a sound control device executes process P140. In process P140, the pseudo-engine sound is generated based on the virtual engine torque and virtual engine speed calculated in process P131.

[0050] In process P140, a predetermined engine sound is used as the sound source of the pseudo engine sound to be generated from the in-vehicle speaker 21. The type of engine sound may be selectable by the driver using the HMI 20, for example. However, in process P140, the sound of the sound source is not used as is. In process P140, the sound pressure of the sound source is changed, for example, by an amplifier, and the frequency of the sound source is changed, for example, by a frequency modulator.

[0051] Process P140 includes process P141 for calculating engine sound pressure and process P142 for calculating engine sound frequency. In process P141, the sound pressure of the pseudo engine sound is calculated from the virtual engine torque using a sound pressure map M11. The sound pressure map M11 is created so that the sound pressure increases as the virtual engine torque increases. In process P142, the frequency of the pseudo engine sound is calculated from the virtual engine speed using a frequency map M12. The frequency map M12 is created so that the frequency increases as the virtual engine speed increases. The virtual engine torque and virtual engine speed change depending on the driver's accelerator operation, shift operation, and clutch operation. By changing the sound pressure and frequency of the pseudo engine sound in accordance with the changing virtual engine torque and virtual engine speed, the driver can be given a sense of realism as if they were driving a real manual-speed internal combustion engine vehicle.

[0052] 6. First Embodiment - Pseudo Sequential Shifter Installed on Steering Wheel 6-1. Automatic Upshift When Steering and Starting As described above, the driver of the electric vehicle 100 can experience operating a manual transmission internal combustion engine vehicle in the electric vehicle 100 by operating the HMI 20 to switch the control mode to manual mode. Simply simulating the operating feel of a manual transmission internal combustion engine vehicle can be enjoyable for the driver, but further improvements in convenience are also being considered.

[0053] Consider a situation in which the driver may feel inconvenienced when starting the electric vehicle 100 while steering after selecting the manual mode. An example of such a situation is when the electric vehicle 100 parked in a parking lot starts moving from a parking space, as shown in Figure 7. In the first embodiment, the pseudo sequential shifter 25 is a pseudo paddle shifter 51 mounted on the steering wheel 41.

[0054] When starting, the virtual shift position is in first gear. The driver increases the virtual engine torque by depressing the accelerator pedal 22 while turning the steering wheel 41. As the virtual engine torque increases, the pseudo engine sound becomes louder, and the vehicle speed and virtual engine speed increase. A driver of a manual transmission internal combustion engine vehicle typically determines how high the engine speed is by using the volume of the engine sound as a guide, and increases the shift position to second gear once the engine speed has reached a certain level. A driver of an electric vehicle 100 that has selected the manual mode will also likely use the virtual engine speed as a guide and consider increasing the virtual shift position to second gear once the vehicle speed has reached a certain level.

[0055] However, at this time, as the steering wheel 41 is turned, the pseudo paddle shifters 51 also rotate and change position. Figure 7 shows the rotation of the steering wheel 41. As the steering wheel 41 is turned and the rotation angle of the steering wheel 41 increases to approximately 180° as shown in the bottom state, the left and right sides of the pseudo paddle shifters 51 are reversed, and as seen from the driver's perspective, the left paddle corresponds to upshifting and the right paddle corresponds to downshifting. This can cause confusion for the driver as to which paddle corresponds to upshifting, making operation difficult. Furthermore, when the rotation angle increases, the driver may change their grip on the steering wheel 41, which can further cause confusion and make operation difficult due to the change in hand.

[0056] In such a situation, it is possible to continue driving without upshifting, but upshifting allows for smoother acceleration. Therefore, in the electric vehicle 100 according to this embodiment, when the virtual engine speed reaches or exceeds a predetermined speed while the steering angle of the steering wheel 24 is large, the virtual shift position is automatically upshifted in accordance with the virtual engine speed. The steering angle of the steering wheel 24 can also be referred to as the rotation angle of the steering wheel 41.

[0057] Fig. 8 is a flow diagram showing an example of processing executed by the electric vehicle 100. The processing shown in the flow diagram of Fig. 8 is realized by the processor 102 executing one or more driving control programs 104 stored in the memory 103.

[0058] 8, first, in step S101, it is determined whether or not the manual mode has been selected as the control mode. If the manual mode has not been selected, the flow ends.

[0059] If 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 predetermined angle. The predetermined angle is set in advance. If the rotation angle of the steering wheel is less than the predetermined angle, the flow ends.

[0060] If the rotation angle of the steering wheel 41 is equal to or greater than the predetermined angle, step S103 is executed. In step S103, it is determined whether the virtual engine speed is equal to or greater than the predetermined speed. In step S103, the processor 102 may determine that the virtual engine speed is equal to or greater than the predetermined speed if the state in which the virtual engine speed is equal to or greater than the predetermined speed continues for a certain period of time or longer, or may determine that the virtual engine speed is less than the predetermined speed if the state in which the virtual engine speed is equal to or greater than the predetermined speed ends before the certain period of time has elapsed. If the virtual engine speed is less than the predetermined speed, the flow ends.

[0061] If the virtual engine speed is equal to or greater than the predetermined speed, step S104 is executed, in which the virtual shift position is upshifted from first gear to second gear.

[0062] 6-2. Effects According to the above processing, an automatic upshift is performed according to the virtual engine speed in situations where the virtual engine speed increases with a large steering angle of the steering wheel 24, such as when starting while turning the steering wheel. This enables smooth acceleration even when the driver has difficulty grasping the position of the paddle corresponding to the upshift, thereby improving drivability.

[0063] 6-3. Predetermined Angle The predetermined angle used as the basis for the determination 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 pseudo paddle shifters 51 are reversed, making it difficult for the driver to grasp the position of the paddles. However, the predetermined angle may be set to, for example, 150° or 120°. Furthermore, the determination in step S102 may be established when the rotation angle of the steering wheel 41 is 90° or greater, with 90° being used as the reference angle at which the positions of the left and right paddles are reversed with respect to a vertical line passing through the center of the steering wheel 41.

[0064] 7. Second Embodiment - Pseudo Paddle Shifters Mounted on a Steering Column In the second embodiment, the pseudo sequential shifter 25 is a pseudo paddle shifter 52 mounted on the steering column 42. As with the first embodiment, consider a situation in which the driver starts the electric vehicle 100 while steering the steering wheel with the manual mode selected. In the second embodiment, too, a problem can arise in which the driver is unable to upshift smoothly when he or she wants to.

[0065] FIG. 9 shows the state of the steering wheel 41 as it rotates. The gray area surrounded by the dashed line indicates the position where the right hand is placed when the steering wheel 41 is in its initial position. Because the pseudo paddle shifters 52 are fixed to the steering column 42, the position of the pseudo paddle shifters 52 itself does not change. However, as the steering wheel 41 rotates, the relative position of the pseudo paddle shifters 52 to the driver's hands changes, making it difficult for the driver to operate the pseudo paddle shifters 52. For example, when the rotation angle of the steering wheel 41 is approximately 90°, the position of the right hand is farther away from the position of the right paddle of the pseudo paddle shifters 52, making it difficult to perform an upshift. As the rotation angle increases, the position of the right hand becomes even farther away from the position of the right paddle of the pseudo paddle shifters 52. As the rotation angle increases, the driver may change their grip on the steering wheel 41. However, even if they do, the relative position of the hand and the pseudo paddle shifters 52 changes from when the steering wheel 41 was in its initial position, which may make it difficult to operate the pseudo paddle shifters 52. Therefore, in the second embodiment as well, when the manual mode is selected and the steering angle of the steering wheel 24 is greater than a predetermined angle, the electric vehicle 100 automatically upshifts the virtual shift position in accordance with the virtual engine speed.

[0066] The process executed by the electric vehicle 100 can be represented by the flowchart of FIG. 8 , as in the first embodiment. The processes performed in steps S101 to S104 are the same as those in the first embodiment. However, the predetermined angle used for the determination in step S102 is set to a smaller angle than in the first embodiment. This is because, in the second embodiment, the driver's right hand moves away from the right paddle of the pseudo paddle shifter 52 before the steering wheel 41 reaches a rotation angle of 90°, making it difficult for the driver to perform an upshift. The predetermined angle may be, for example, 80°.

[0067] This processing by the electric vehicle 100 enables smooth acceleration by upshifting even in situations where the steering angle of the steering wheel 24 becomes large and it becomes difficult for the driver to operate the pseudo paddle shifters 52. In this way, drivability can be improved.

[0068] 8. Upshift Timing The above describes automatic upshifting by the electric vehicle 100 in accordance with the virtual engine speed. While the above example illustrates starting while steering, the application of automatic upshifting is not limited to starting. Furthermore, the shift position is not limited to upshifting from first to second. Even when not starting, if the virtual engine speed increases to a predetermined speed or higher while the rotation angle of the steering wheel 41 is equal to or greater than a predetermined angle, the processor 102 automatically upshifts. Furthermore, if the virtual shift position is second or higher, the shift position is increased by one gear. This allows smooth acceleration even in situations where the driver has difficulty operating the pseudo-sequential shifter 25 due to a large steering angle of the steering wheel 24, as in starting while steering, thereby improving convenience for the driver.

[0069] In other words, the timing of an automatic upshift can be determined based on the vehicle speed. FIG. 10 shows the relationship between the vehicle speed and the virtual engine speed of the electric vehicle 100. The dotted circles indicate the timing of switching the virtual shift position when an automatic upshift is performed. Although FIG. 10 shows five virtual shift positions, from first to fifth, this number of shift positions is merely an example. As shown in FIG. 10 , if the pseudo-sequential shifter 25 is not operated and the clutch opening is constant, there is a one-to-one correspondence between the vehicle speed and the virtual engine speed at a certain shift position. Therefore, it can also be said that the timing of an upshift determined based on the virtual engine speed is determined based on the vehicle speed corresponding to the shift position.

[0070] 9. Notification to the Driver The HMI 20 may notify the driver that an automatic upshift has been performed by the electric vehicle 100. For example, the current shift position may be displayed on the display of the HMI 20, and the driver may be able to know that the shift position has been changed by looking at the display.

[0071] Alternatively, the driver does not need to be explicitly notified that an automatic upshift has occurred. When the virtual shift position is changed by an upshift, the virtual engine torque decreases, causing the engine noise to decrease discontinuously. Therefore, the driver can notice the automatic upshift even without any notification such as a display.

[0072] 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 wheels, 6R Rear wheels, 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 Steering angle sensor, 15 Shift switch, 20 HMI, 21 In-car speaker, 22 Accelerator pedal, 23 Brake pedal, 24 Steering, 25 Pseudo sequential shifter, 41 Steering wheel, 42 Steering column, 51 Pseudo paddle shifter, 52 Pseudo paddle shifter, 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, comprising: an accelerator pedal used to drive the electric vehicle; a pseudo-sequential shifter installed on a steering wheel simulating a sequential shifter used to change gears in a manually-shifted internal combustion engine vehicle; and a control device that controls the electric vehicle in response to operation of the accelerator pedal, wherein the control device is configured to execute a control mode that, at the driver's selection, associates operation of the pseudo-sequential shifter with a virtual shift position, which is a virtual shift position, and associates the accelerator pedal opening, the virtual shift position, and the vehicle speed of the electric vehicle with the torque of the electric motor; and when the steering angle of the steering wheel becomes equal to or greater than a predetermined angle while the control mode is being executed, automatically upshifts the virtual shift position in response to the vehicle speed.

2. An electric vehicle as claimed in claim 1, characterized in that the pseudo-sequential shifter is installed on the steering wheel.

3. An electric vehicle as claimed in claim 1, characterized in that the pseudo-sequential shifter is installed on a steering column.

4. An electric vehicle as claimed in claim 2, characterized in that the pseudo-sequential shifter is a button provided on the steering wheel.

5. An electric vehicle according to claim 2 or 3, characterized in that the pseudo sequential shifter is a pseudo paddle shifter that simulates a paddle shifter.

6. An electric vehicle according to claim 5, wherein the pseudo paddle shifter is a pair of paddles attached to the left and right of the steering wheel.

7. An electric vehicle as claimed in any one of claims 1 to 4, further comprising a speaker that outputs inside the vehicle a pseudo engine sound that reproduces the engine sound of the manually-shifted internal combustion engine vehicle, and wherein the control device is configured to further execute the following while the control mode is being executed: playing the pseudo engine sound from the speaker; and associating the accelerator pedal opening, the virtual shift position, and the vehicle speed with the volume of the pseudo engine sound.

8. An electric vehicle as claimed in any one of claims 1 to 4, characterized in that the control device is configured to automatically upshift the virtual shift position from 1st gear to 2nd gear in accordance with the vehicle speed when the steering angle of the steering wheel becomes equal to or greater than a predetermined angle when the electric vehicle starts moving while the control mode is being executed.

9. A program for controlling an electric vehicle having an electric motor as a drive source, an accelerator pedal used for driving, and a pseudo-sequential shifter installed on the steering wheel simulating a sequential shifter used for shifting gears in manually variable internal combustion engine vehicles, the program causing a computer to execute the following operations: controlling the electric vehicle in response to operation of the accelerator pedal; executing a control mode in which, at the driver's option, the operation of the pseudo-sequential shifter is associated with a virtual shift position, which is a virtual shift position, and the accelerator pedal opening, the virtual shift position, and the vehicle speed of the electric vehicle are associated with the torque of the electric motor; and when the steering angle of the steering wheel becomes equal to or greater than a predetermined angle while the control mode is being executed, automatically upshifting the virtual shift position in response to the vehicle speed.

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