Electric vehicles

Abstract

To provide an electric automobile allowing a driver to experience operation of a manual shift-type internal combustion engine vehicle, and capable of replicating engine braking even while a charging acceptance amount of an on-vehicle battery is small.SOLUTION: The present disclosure relates to an electric automobile including an electric motor as a driving source. The electric automobile includes: a driving operation member used for driving the electric automobile; a pseudo shift operation member imitating an operation member used for shift operation of a manual shift-type internal combustion engine vehicle; a control device for controlling the electric automobile according to operation of the driving operation member; and an on-vehicle battery charged with electrical energy generated when regenerative braking is actuated. When a selection is made by a driver, the control device executes a control mode in which operation of the pseudo shift operation member is associated with torque of the electric motor. In addition, during execution of the control mode, the control device notifies the driver of a shift position according to a charging acceptance amount of the on-vehicle battery.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] Japanese Patent No. 6787507 discloses a prior art related to an electric vehicle capable of pseudo-reproducing a manual shift operation of a vehicle equipped with a manual transmission having an internal combustion engine as a power source (hereinafter referred to as a manual shift type internal combustion engine vehicle) by controlling an electric motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Engine braking is a braking method peculiar to manual shift type internal combustion engine vehicles. According to the above prior art, the operation of a manual shift type internal combustion engine vehicle can be experienced in an electric vehicle. However, although studies have been made to reproduce clutch operations and shift operations, no studies have been made to reproduce engine braking without impairing the operating feeling as if actually operating a manual shift type internal combustion engine vehicle.

Means for Solving the Problems

[0005] The present disclosure relates to an electric vehicle having an electric motor as a drive source. The electric vehicle includes a driving operation member used for driving the electric vehicle, a pseudo-shift operation member imitating an operation member used for a shift operation of a manual shift type internal combustion engine vehicle, a control device that controls the electric vehicle in response to an operation of the driving operation member, It includes an onboard battery that charges the electrical energy generated when regenerative braking is activated. The control device is The system executes a control mode in which the operation of the simulated gear shifting control member is associated with the torque of the electric motor, based on the driver's selection. When the above control mode is executed, Determining a virtual shift position based on the operation of a simulated gear shift operating member, When the above electric vehicle is in motion and there is no accelerator input, regenerative braking is activated with a strength corresponding to the virtual shift position. It is configured to notify the driver of the shift position corresponding to the amount of charge the onboard battery has received. [Effects of the Invention]

[0006] According to the electric vehicle disclosed herein, the engine braking of a manually operated internal combustion engine vehicle is reproduced by regenerative braking. While regenerative braking may be limited by the amount of charge the onboard battery can accept, in such cases the driver is notified of a shift position corresponding to the amount of charge accepted, and the driver can adjust the shift position to reproduce engine braking even when the amount of regenerative power that can be accepted is low. For the driver, this allows them to continue driving the electric vehicle without compromising the feel of operating a manually operated internal combustion engine vehicle that is close to that of a real one, thereby increasing driver satisfaction. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows the configuration of an electric vehicle according to an embodiment of this disclosure. [Figure 2] This is a tree diagram showing an example of an electric vehicle control mode that can be selected by the control unit. [Figure 3] This is a tree diagram showing an example of an electric vehicle control mode that can be selected by the control unit. [Figure 4] This diagram shows the configuration of a control device related to the driving control of an electric vehicle. [Figure 5]This diagram shows the configuration of a control device related to sound control in an electric vehicle. [Figure 6] This diagram shows the configuration of the control device related to virtual engine braking. [Figure 7] This is a conceptual diagram illustrating the driver's notification regarding the shift position. [Figure 8] This flowchart shows the first example of the control device's processing related to notifying the driver. [Figure 9] This flowchart shows a second example of the control device's processing related to notifying the driver. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described with reference to the attached drawings.

[0009] 1. Configuration of the powertrain of an electric vehicle Figure 1 is a schematic diagram showing the configuration of an electric vehicle 100 according to an embodiment of this disclosure. First, the configuration of the power system of the electric vehicle 100 will be described with reference to Figure 1.

[0010] The electric vehicle 100 is equipped with two electric motors (M) 4F and 4R at the front and rear. The electric motors 4F and 4R have the function of converting supplied power into torque and the function of converting input torque into power. The electric motors 4F and 4R are, for example, three-phase AC motors. The front electric motor 4F is connected to the front drive shaft 5F which drives the front wheel 6F. The rear electric motor 4R is connected to the rear drive shaft 5R which drives the rear wheel 6R. The front wheel 6F is suspended by an independently electronically controlled front suspension 7F on the left and right sides. The rear wheel 6R is suspended by an independently electronically controlled rear suspension 7R on the left and right sides.

[0011] The electric motors 4F and 4R are used as power sources for driving. Inverters (INV) 3F and 3R are respectively attached to the front electric motor 4F and the rear electric motor 4R. The front inverter 3F and the rear inverter 3R are respectively connected to the battery (BATT) 2. The battery 2 stores the electrical energy for driving the electric motors 4F and 4R. That is, the electric vehicle 100 is a battery electric vehicle (BEV) that runs on the electrical energy stored in the battery 2. The inverters 3F and 3R are, for example, voltage source inverters, and control the torque of the electric motors 4F and 4R by PWM control.

[0012] Also, the front electric motor 4F and the rear electric motor 4R each have a function as a generator that generates regenerative power from the torque input from the front drive shaft 5F and the rear drive shaft 5R. By operating the electric motors 4F and 4R as generators during the running of the electric vehicle 100, the electric vehicle 100 can be decelerated by regenerative braking. At this time, the regenerative power generated by the power generation of the electric motors 4F and 4R is charged to the battery 2 via the inverters 3F and 3R.

[0013] In the above description, the driving electric motors 4F and 4R are described as having a function as a generator. However, the electric vehicle 100 may be provided with a driving electric motor and generators separately arranged from the driving electric motor at the front and the rear.

[0014] 2. Configuration of the control system of the electric vehicle Subsequently, the configuration of the control system of the electric vehicle 100 will be described while referring to FIG. 1.

[0015] 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 to estimate the state of charge (SOC) of the battery 2. In addition, the functions of the battery management system 10 include a function to estimate the amount of charge the battery 2 can accept, that is, the amount obtained by subtracting the current charge from the full charge.

[0016] The electric vehicle 100 is equipped with a vehicle speed sensor 11. At least one of the 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 the accelerator pedal 22 and outputs a signal indicating the amount the accelerator pedal 22 is pressed, i.e., the accelerator opening. Furthermore, the electric vehicle 100 is also 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 amount the brake pedal 23 is pressed, i.e., the brake opening.

[0017] The accelerator pedal 22 and brake pedal 23 are driving control components used to operate the electric vehicle 100. Separately from these driving control components, the electric vehicle 100 is equipped with simulated gear shifting control components that mimic the control components used to operate gears in a manually operated internal combustion engine vehicle. The simulated gear shifting control components include the following simulated H-type shifter 24, simulated paddle shifter 25, and simulated clutch pedal 26.

[0018] The pseudo-H-type shifter 24 is a dummy, different from a real H-type shifter. The pseudo-H-type shifter 24 has a structure similar to a shift stick installed on the console and can move along an H-shaped gate between shift positions. However, since the electric vehicle 100 does not have a real transmission, the shift positions of the pseudo-H-type shifter 24 are virtual shift positions. The pseudo-H-type shifter 24 is equipped with a shift position sensor 14. The shift position sensor 14 outputs a signal indicating the shift position selected by the pseudo-H-type shifter 24.

[0019] The simulated paddle shifter 25 is a dummy, different from a real paddle shifter, which is a type of sequential shifter. The simulated paddle shifter 25 has a structure that resembles a shift paddle attached to the steering wheel, and the left and right paddles can be moved independently. The simulated paddle shifter 25 is equipped with a paddle shift switch 15. The paddle shift switch 15 outputs an upshift signal when the right paddle is pulled and a downshift signal when the left paddle is pulled.

[0020] The simulated clutch pedal 26 is a dummy, different from the actual clutch pedal. The simulated clutch pedal 26 has a structure similar to the clutch pedal found in conventional manual transmission internal combustion engine vehicles. For example, the simulated clutch pedal 26 is equipped with a reaction force mechanism that generates a reaction force in response to the driver's pressing. The position when no force is applied is the starting position of the simulated clutch pedal 26, and the position when it is pressed all the way down is the ending position of the simulated clutch pedal 26. The driver can operate the simulated clutch pedal 26 from the starting position to the ending position, resisting the reaction force from the reaction force mechanism. The simulated clutch pedal 26 is equipped with a clutch pedal stroke sensor 16. The clutch pedal stroke sensor 16 outputs a signal indicating the amount the simulated clutch pedal 26 is pressed. Since the electric vehicle 100 does not have a real clutch, the amount of operation of the simulated clutch pedal 26, i.e., the clutch opening, is a virtual clutch opening.

[0021] Although the simulated clutch pedal 26 is a pedal-type operating device operated with the foot, a lever-type or dial-type operating device operated by hand may also be provided as a simulated clutch operating device. The simulated clutch operating device can be operated by the driver against the reaction force from the starting position to the ending position, and various structures can be adopted as long as the driver can feel the operation sensation of a clutch pedal, similar to that of a conventional manual transmission internal combustion engine, with their feet or hands.

[0022] Furthermore, the electric vehicle 100 is equipped with a human-machine interface (HMI) 20 and an in-car speaker 21 as an interface with the driver. The HMI 20 has a touch panel display. The HMI 20 displays information on the touch panel display and accepts input from the driver through touch operation on the touch panel display. The in-car speaker 21 provides information to the driver by voice and can also output a simulated engine sound, which will be described later.

[0023] The electric vehicle 100 is equipped with a control device 101. Sensors and controlled devices mounted on the electric vehicle 100 are connected to the control device 101 via an in-vehicle network. In addition to the battery management system 10, vehicle speed sensor 11, accelerator pedal stroke sensor 12, brake pedal stroke sensor 13, shift position sensor 14, paddle shift switch 15, and clutch pedal stroke sensor 16, various other sensors are also installed in the electric vehicle 100.

[0024] 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 RAM for temporarily recording data and 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 the program 104 and data 105 from the memory 103 and executes them, and generates control signals based on signals acquired from each sensor. The control device 101 may have one or more processors 102.

[0025] The control device 101 can control the electric vehicle 100 in various control modes. The control mode can be selected by the driver by touching the touch panel display of the HMI 20. 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. The control modes of the electric vehicle 100 by the control device 101 that can be selected by the driver by operating the HMI 20 will be described below.

[0026] 3. Control modes for electric vehicles Figures 2 and 3 are tree diagrams showing examples of control modes for the electric vehicle 100 that can be selected by the control device 101. In the HMI 20, the selection screen is displayed on the touch panel display according to the control tree shown in Figure 2.

[0027] The initial screen of the HMI20 displays the option "Control Mode" OP000. Selecting "Control Mode" OP000 displays the options "Automatic Mode" OP110 and "Manual Mode" OP120 on the touch panel display. If "Automatic Mode" OP110 is selected, the control mode of the electric vehicle 100 switches to automatic mode. Automatic mode is the control mode for driving the electric vehicle 100 as a normal BEV. In automatic mode, the driver can basically drive the electric vehicle 100 using only the accelerator pedal 22, brake pedal 23, and the steering wheel (not shown). In automatic mode, the shift operation of the simulated H-shaped shifter 24, the shift operation of the simulated paddle shifter 25, and the clutch operation of the simulated clutch pedal 26 are disabled.

[0028] If 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 that makes the electric vehicle 100 operate like a manually operated internal combustion engine. By selecting the option "Manual Mode" OP120, the options "Shift Mode" OP210, "Engine Characteristics" OP220, "Engine Sound" OP230, "Drive Mode" OP240, and "Suspension Characteristics" OP250 are displayed on the touch panel display. The driver can determine the characteristics of a manually operated internal combustion engine that they want the electric vehicle 100 to simulate by appropriately combining these options OP210-OP250.

[0029] The "Shift Mode" option OP210 is an option for selecting the shift mode of the manual transmission when operating the electric vehicle 100 like a manually operated internal combustion engine vehicle. As shown in Figure 2, selecting the "Shift Mode" option OP210 displays the options "Paddle Shift" OP311 and "Stick Shift" OP312 on the touch panel display. If the "Paddle Shift" option OP311 is selected, the shift mode of the manual transmission reproduced in the electric vehicle 100 switches to paddle shift mode. Paddle shift mode is a mode in which the simulated paddle shifter 25 is used for shifting. In paddle shift mode, the shift operation of the simulated H-type shifter 24 is disabled. In paddle shift mode, the operation when the gear ratio of the manual transmission is switched is reproduced by the shift operation of the simulated paddle shifter 25. In a real paddle shift type manual transmission, clutch operation is performed automatically by the robot. Therefore, in paddle shift mode, clutch operation of the simulated clutch pedal 26 is not required. In paddle shift mode, the clutch operation of the simulated clutch pedal 26 is disabled.

[0030] If the option "Stick Shift" OP312 is selected, the stick shift mode is selected. Stick shift mode is a mode in which the simulated H-type shifter 24 is used for shifting. In stick shift mode, the shifting operation of the simulated paddle shifter 25 is disabled. In stick shift mode, the operation when the gear ratio of a manual transmission is switched is reproduced by the shifting operation of the simulated H-type shifter 24. Real H-type shifter manual transmissions come in two types: one in which the driver performs the clutch operation themselves, and another in which the clutch operation is entrusted to a robot. If the option "Stick Shift" OP312 is selected, the options "With Clutch Operation" OP411 and "Without Clutch Operation" OP412 are displayed on the touch panel display. If the option "With Clutch Operation" OP411 is selected, the stick shift mode switches to a mode that requires clutch operation of the simulated clutch pedal 26. On the other hand, if the option "Without Clutch Operation" OP412 is selected, the clutch operation of the simulated clutch pedal 26 is disabled, and the stick shift mode switches to a mode that does not require clutch operation.

[0031] The "Engine Characteristics" option OP220 is an option for selecting the characteristics of the internal combustion engine when operating the electric vehicle 100 like a manually operated internal combustion engine vehicle. As shown in Figure 2, selecting the "Engine Characteristics" option OP220 displays the options "Low-to-Medium RPM Type" OP321, "High-RPM Type" OP322, and "Full-RPM Type" OP323 on the touch panel display. If the "Low-to-Medium RPM Type" OP321 option is selected, the characteristics of the internal combustion engine reproduced in the electric vehicle 100 will switch to a low-to-medium RPM type, where the torque in the low-to-medium RPM range is relatively high. If the "High-RPM Type" OP322 option is selected, the characteristics of the internal combustion engine reproduced in the electric vehicle 100 will switch to a high-RPM type, where the torque in the high-RPM range is relatively high. And if the "Full-RPM Type" OP323 option is selected, the characteristics of the internal combustion engine reproduced in the electric vehicle 100 will switch to a full-range type, where the torque is uniform across the entire range. However, low-to-medium RPM, high-RPM, and full-range RPM types are merely examples of engine characteristics that can be reproduced by the control of the electric vehicle 100.

[0032] The "Engine Sound" option (OP230) is used to select the engine sound to be reproduced in the electric vehicle 100. As shown in Figure 2, selecting the "Engine Sound" option (OP230) displays the following options on the touch panel display: "Inline 4-cylinder turbocharged engine" (OP331), "Flat 6-cylinder engine" (OP332), and "V12 engine" (OP333). If "Inline 4-cylinder turbocharged engine" (OP331) is selected, the engine sound reproduced in the electric vehicle 100 switches to the sound of an inline 4-cylinder turbocharged engine. If "Flat 6-cylinder engine" (OP332) is selected, the engine sound reproduced in the electric vehicle 100 switches to the sound of a flat 6-cylinder engine. And if "V12 engine" (OP333) is selected, the engine sound reproduced in the electric vehicle 100 switches to the sound of a V12 engine. However, the inline 4-cylinder turbocharged engine, flat 6-cylinder engine, and V12 engine are just examples of engine sounds that can be reproduced in the electric vehicle 100.

[0033] The "Drive Mode" option OP240 is used to select the drive mode of the electric vehicle 100. As shown in Figure 3, selecting the "Drive Mode" option OP240 displays the options "Four-Wheel Drive" OP341 and "Rear-Wheel Drive" OP342 on the touch panel display. If the "Four-Wheel Drive" option OP341 is selected, the drive mode of the electric vehicle 100 switches to four-wheel drive mode. In four-wheel drive mode, the front wheels 6F are driven by the front electric motor 4F, and the rear wheels 6R are driven by the rear electric motor 4R. The torque distribution between the front wheels 6F and the rear wheels 6R can be fixed or variable by the control of the electric motors 4F and 4F by inverters 3F and 3R. If the "Rear-Wheel Drive" option OP342 is selected, the drive mode of the electric vehicle 100 switches to rear-wheel drive mode. In rear-wheel drive mode, only the rear wheels 6R are driven by the rear electric motor 4R. However, in the electric vehicle 100, it is also possible to select a front-wheel drive mode in addition to the rear-wheel drive mode, where only the front wheels 6F are driven by the front electric motor 4F.

[0034] The "Suspension Characteristics" option OP250 is used to select the suspension characteristics of the electric vehicle 100. As shown in Figure 3, selecting the "Suspension Characteristics" option OP250 displays the options "Soft" OP351, "Hard" OP352, and "Medium" OP353 on the touch panel display. If "Soft" OP351 is selected, the suspension characteristics of the electric vehicle 100 are switched to soft mode. In soft mode, the damping force of suspensions 7F and 7R is reduced. If "Hard" OP352 is selected, the suspension characteristics of the electric vehicle 100 are switched to hard mode. In hard mode, the damping force of suspensions 7F and 7R is increased. If "Medium" OP353 is selected, the suspension characteristics of the electric vehicle 100 are switched to medium mode. In medium mode, the damping force of suspensions 7F and 7R is set to an intermediate damping force between soft mode and hard mode. However, since the suspensions 7F and 7R are electronically controlled, their suspension characteristics can be widely adjusted. Therefore, the soft mode, hard mode, and medium mode are merely examples of suspension characteristics that can be achieved in the electric vehicle 100. Furthermore, the drive mode and suspension characteristics may be selectable not only in manual mode but also in automatic mode.

[0035] By operating the HMI20's touch panel display according to the control tree described above, the driver can switch the control mode of the electric vehicle 100 to their preference. The switchable control modes include modes related to the driving control of the electric vehicle 100 and modes related to the sound control of the electric vehicle 100. Specifically, the mode related to the "engine sound" option OP230 is a mode related to sound control, while all others are modes related to driving control. The following chapters will describe the driving control and sound control of the electric vehicle 100 by the control device 101.

[0036] 4. Driving control of electric vehicles Figure 4 shows the configuration of the control device 101 related to the driving control of the electric vehicle 100. More specifically, Figure 2 shows the configuration related to torque control within the driving control. The processor 102 functions as a driving control device when one or more driving control programs 104 stored in memory 103 are executed by the processor 102.

[0037] The control device 101, which functions as a driving control device, receives a control mode signal from the HMI 20. The control mode signal contains information about the control mode selected by the driver. Based on the control mode signal, the control device 101 performs process P110. In process P110, the control mode is switched according to the control mode signal. The switch between automatic mode and manual mode is particularly influential on driving control.

[0038] 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 the accelerator opening from the signal of the accelerator pedal stroke sensor 12. The control device 101 has a motor torque map with accelerator opening and vehicle speed as parameters. The control device 101 inputs the vehicle speed and accelerator opening into the motor torque map and controls inverters 3F and 3R to generate the torque obtained from the motor torque map in electric motors 4F and 4R.

[0039] When the control mode is switched to manual mode, the control device 101 executes process P130 for torque calculation in manual mode. Process P130 includes process P131 for calculating the torque to be generated by the drive wheels. Process P130 also includes processes P132 and P133. Process P132 is for calculating the torque to be generated by the front electric motor 4F, and process P133 is for calculating the torque to be generated by the rear electric motor 4R. Processes P132 and P133 are executed according to the drive wheel torque calculated in process P130 and the torque distribution between the front wheel 6F and the rear wheel 6R.

[0040] The vehicle model MOD01 is used to calculate the drive wheel torque in process P131. Vehicle model MOD01 includes the engine model MOD11, the clutch model MOD12, and the transmission model MOD13. The engine virtually realized by vehicle model MOD01 is called the virtual engine, the virtually realized clutch is called the virtual clutch, and the virtually realized transmission is called the virtual transmission. The engine model MOD11 models the virtual engine. The clutch model MOD12 models the virtual clutch. The transmission model MOD13 models the virtual transmission.

[0041] Engine model MOD11 calculates virtual engine speed and virtual engine torque. Virtual engine speed is calculated from vehicle speed, overall reduction ratio, and virtual clutch slip ratio. Virtual engine torque is calculated from virtual engine speed and accelerator opening. Vehicle speed is obtained from the signal of vehicle speed sensor 11. Accelerator opening is obtained from the signal of 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 engine model MOD11, the relationship between virtual engine speed and virtual engine torque is defined for each accelerator opening. The engine characteristics of engine model MOD11 can be selected by the driver by operating the HMI20. In the example shown in Figure 2, engine characteristics can be selected from low-to-medium RPM type, high-RPM type, and full-range type.

[0042] The clutch model MOD12 calculates the torque transmission gain. The torque transmission gain is used to calculate the degree of torque transmission of the virtual clutch according to the clutch opening. When the clutch-operated stick shift mode is selected as the shift mode, the clutch opening is obtained from the signal of the clutch pedal stroke sensor 16. The clutch opening is 0% at the starting position of the simulated clutch pedal 26 and 100% at the ending position of the simulated clutch pedal 26. In the clutch model MOD12, a torque transmission gain is assigned to the clutch opening. The torque transmission gain is converted into the clutch torque capacity of the virtual clutch, i.e., the virtual clutch torque capacity. 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. In addition, the clutch model MOD12 calculates the slip ratio as 1 minus the torque transmission gain. The slip ratio is used in the calculation of the virtual engine speed in the engine model MOD11.

[0043] When paddle shift mode is selected as the shift mode, the clutch opening angle input to clutch model MOD12 is calculated using the clutch operation model. Similarly, when clutchless stick shift mode is selected as the shift mode, the clutch opening angle input to clutch model MOD12 is calculated using the clutch operation model. The clutch operation model is a model that simulates the clutch operation of a model driver. When paddle shift mode is selected, the clutch operation model receives signals from the vehicle speed, virtual engine speed, and paddle shift switch 15. When clutchless stick shift mode is selected, the clutch operation model receives signals from the vehicle speed, virtual engine speed, and shift position sensor 14.

[0044] Signals from the paddle shift switch 15 and the shift position sensor 14 are used to time the clutch operation. When the driver's shift operation is detected by the signals from the paddle shift switch 15 and the shift position sensor 14, the clutch operation model maximizes the clutch opening to disengage the virtual clutch. Vehicle speed and virtual engine speed are used to calculate the clutch opening. In order to smoothly match the rotational speed of the virtual transmission input shaft, which is calculated from the vehicle speed, with the virtual engine speed, the clutch operation model calculates the clutch opening based on the rotational speed difference between the rotational speed of the virtual transmission input shaft and the virtual engine speed.

[0045] Transmission model MOD13 calculates the virtual gear ratio. The virtual gear ratio is the gear ratio determined by the virtual shift position in the virtual transmission. The virtual gear ratio is set for each shift position. The largest virtual gear ratio is set for 1st gear, and the virtual gear ratio decreases in the order of 2nd gear, 3rd gear, 4th gear, ... In stick shift mode, the shift position is mapped one-to-one with the signal from the shift position sensor 14. In paddle shift mode, the shift position is moved up one step in response to an upshift signal from the paddle shift switch 15, and downshifted one step in response to a downshift signal from the paddle shift switch 15. Note that the number of shift positions is physically determined in the pseudo-H type shifter 24, whereas there are no physical constraints on the number of shift positions in the pseudo-paddle shifter 25. Therefore, the transmission model MOD 13 can be different for stick shift mode and paddle shift mode, and the number of shift positions in paddle shift mode can be greater than the number of shift positions in stick shift mode.

[0046] Transmission model MOD13 calculates virtual transmission torque using virtual gear ratios and virtual clutch torque. Virtual transmission torque is a virtual torque output from the virtual transmission. Control device 101 controls inverters 3F and 3R to change the output torque of electric motors 4F and 4R according to the virtual transmission torque. The virtual transmission torque changes discontinuously in accordance with the switching of virtual gear ratios. This discontinuous change in virtual transmission torque generates torque shocks in the electric vehicle 100, creating the impression of a vehicle with a stepped transmission.

[0047] Vehicle model MOD01 calculates drive wheel torque from virtual transmission torque and reduction ratio. 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 to the front wheels (6F) and rear wheels (6R) can be fixed, or it can be actively or passively changed. 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).

[0048] In process P132, the torque of the front electric motor 4F (front motor torque) in manual mode is calculated by multiplying the drive wheel torque calculated in process P131 by the torque distribution ratio to the front wheel 6F and the reduction ratio from the output shaft of the front electric motor 4F to the front wheel 6F. The control device 101 controls the front inverter 3F to generate the front motor torque calculated in process P132 at the front electric motor 4F.

[0049] In process P133, the torque of the rear electric motor 4R (rear motor torque) in manual mode is calculated by multiplying the drive wheel torque calculated in process P131 by the torque distribution ratio to the rear wheel 6R and the reduction ratio from the output shaft of the rear electric motor 4R to the rear wheel 6R. The control device 101 controls the rear inverter 3R to generate the rear motor torque calculated in process P133 at the rear electric motor 4R.

[0050] In the configuration shown in Figure 2, the battery management system 10 and the brake pedal stroke sensor 13 are not necessarily required for the above-described driving control. However, if switching the control mode affects the State of Charge (SOC) of the battery 2, the signal from the battery management system 10 may be used as information to determine whether or not to switch the control mode. Also, 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 that the brake pedal 23 is pressed. In that case, the signal from the brake pedal stroke sensor 13 can be used as information to determine whether the brake pedal 23 is pressed.

[0051] 5. Sound control in electric vehicles Figure 5 shows the configuration of a control device 101 related to sound control of an electric vehicle 100. One or more sound control programs 104 stored in memory 103 are executed by the processor 102, thereby enabling the processor 102 to function as a sound control device. The processor 102 that functions as a torque control device and the processor 102 that functions as a sound control device may be separate processors or the same processor.

[0052] The control device 101, acting as a sound control device, can generate artificially produced sounds from the in-vehicle speaker 21. One of these artificial sounds is a simulated engine sound that resembles the engine sound of a conventional internal combustion engine vehicle. When a control mode signal indicating that manual mode has been selected is input from the HMI 20, the control device 101, acting as a sound control device, executes process P140. In process P140, a simulated engine sound is generated based on the virtual engine torque and virtual engine speed calculated in process P131.

[0053] In process P140, the engine sound selected by HMI20 is used as the sound source for the simulated engine sound generated by the in-car speaker 21. In the example shown in Figure 2, the engine sound selected from a straight-four turbocharged engine, a flat-six engine, and a V12 engine is used as the sound source for the simulated engine sound. However, in process P140, the sound source is not used as is. In process P140, for example, the sound pressure of the sound source is changed by an amplifier, and for example, the frequency of the sound source is changed by a frequency modulator.

[0054] Process P140 includes process P141, which calculates engine sound pressure, and process P142, which calculates engine sound frequency. In process P141, the sound pressure of the simulated engine sound is calculated from the virtual engine torque using the sound pressure map M11. The sound pressure map M11 is designed so that the sound pressure increases as the virtual engine torque increases. In process P142, the frequency of the simulated engine sound is calculated from the virtual engine speed using the frequency map M12. The frequency map M12 is designed so that the frequency increases as the virtual engine speed increases. The virtual engine torque and virtual engine speed change according to the driver's accelerator, shift, and clutch operations. By changing the sound pressure and frequency of the simulated engine sound in accordance with these changing virtual engine torque and virtual engine speed, it is possible to give the driver a sense of realism as if they were driving a real manual transmission internal combustion engine.

[0055] 6. Reproduction of engine braking using regenerative braking 6-1. Overview The driver of the electric vehicle 100 can experience operating a manually operated internal combustion engine by operating the HMI 20 to switch the control mode to manual mode. While the control mode is set to manual mode, the electric vehicle 100 is controlled to replicate the behavior of a manually operated internal combustion engine.

[0056] One of the behaviors unique to manually operated internal combustion engine vehicles is engine braking. In the manual mode of the electric vehicle 100, the operation of engine braking is also reproduced. However, since the electric vehicle 100 does not have a real transmission, the engine braking that operates in manual mode is a virtual engine brake simulated by regenerative braking. Hereafter, the engine braking that is virtually realized by regenerative braking will be referred to as virtual engine braking.

[0057] Figure 6 shows the process related to the operation of the virtual engine brake by the control device 101. The process related to the operation of the virtual engine brake includes a process P151 for determining whether or not the virtual engine brake is activated and a process P152 for activating the regenerative brake. These processes are performed by the control device 101, which acts as a driving control device.

[0058] Process P151 determines whether or not to activate the engine brake. The control device 101 activates the virtual engine brake when the electric vehicle 100 is running in manual mode and there is no accelerator input. Whether or not manual mode is selected is obtained from the control mode signal input from the HMI 20. Whether or not there is accelerator input, that is, whether or not the accelerator pedal 22 is pressed by the driver, is obtained from the signal of the accelerator pedal stroke sensor 12. In addition, whether or not the electric vehicle 100 is running can be obtained from the signal of the vehicle speed sensor 11, and if the vehicle speed is not 0, it is determined that the electric vehicle 100 is running. Based on the signals obtained from the HMI 20, the vehicle speed sensor 11 and the accelerator pedal stroke sensor 12, the control device 101 decides to activate the virtual engine brake if the electric vehicle 100 is running in manual mode and the accelerator pedal 22 is not pressed.

[0059] If it is decided to activate the virtual engine brake, the control device 101 executes process P152. In process P152, the electric motors 4F and 4R are controlled to convert the torque input from the front drive shaft 5F and rear drive shaft 5R into regenerative power to apply the regenerative brake. The strength of the regenerative brake is determined according to the virtual shift position. The activation of the regenerative brake replicates the engine brake of a manually operated internal combustion engine.

[0060] By replicating engine braking in this way, the behavior of the electric vehicle 100 can be made closer to that of a real manually operated internal combustion engine. However, unlike engine braking in an actual manually operated internal combustion engine, the use of regenerative braking may be limited depending on the state of battery 2. Specifically, if the charge acceptance capacity of battery 2 is insufficient, there will be no destination for the regenerative power generated by regenerative braking to be charged, thus limiting the use of regenerative braking.

[0061] Here, engine braking works more strongly the larger the gear ratio. In the manual mode of the electric vehicle 100, to replicate engine braking, stronger regenerative braking is activated the larger the virtual gear ratio. In other words, if the virtual gear ratio is small, it is possible to replicate engine braking without activating strong regenerative braking. The virtual gear ratio increases as the virtual shift position moves towards the downshift side. Therefore, in manual mode, the electric vehicle 100 notifies the driver about the virtual shift position when the charge input is insufficient or is expected to be insufficient. The notifications given to the driver are explained below with specific examples. In the following explanation, we assume that the virtual shift position consists of six gears from 1st to 6th, but similar notifications are given when the number of shift positions in the virtual shift position is greater or less than that.

[0062] 6-2. Scenarios for using virtual engine braking Figure 7 shows an example of a scenario in which virtual engine braking is expected to be used frequently, depicting an electric vehicle 100 driving down a mountain road 200 with a continuous downhill slope.

[0063] At point (a), when the electric vehicle 100 approaches the mountain road 200, the battery 2 has a sufficiently large charge capacity. As the electric vehicle 100 enters the mountain road 200, the driver begins to engage virtual engine braking by downshifting the virtual shift position to reduce the use of the brake pedal 23.

[0064] For a while after starting to drive on Mountain Road 200, the battery charge is sufficient, and virtual engine braking is available regardless of the virtual shift position. During this time, the driver will not be notified about the shift position, or they will be notified that all shift positions are selectable.

[0065] As the virtual engine is used, battery 2 charges, and at point (b), the charge level becomes insufficient to use virtual engine braking in 1st gear. The driver is then notified to select an upshift position, i.e., 2nd gear or higher. If the driver complies with the notification and shifts to 2nd gear or higher, virtual engine braking remains available.

[0066] As battery 2 continues to charge and its charge capacity decreases, and the charge capacity becomes insufficient to use virtual engine braking in 2nd gear, the driver will be notified to select a shift position of 3rd gear or higher. If the driver complies with the notification and shifts to 3rd gear or higher, virtual engine braking will remain available.

[0067] The same applies to the following: As battery 2 charges and the amount of charge it accepts decreases, the driver is notified to select a shift position corresponding to the amount of charge it accepts.

[0068] 6-3. First example of processing Figure 8 is a flowchart showing an example of the processing performed by the control device 101. The series of processes shown in Figure 8 are repeatedly executed at a predetermined control cycle, for example, while the electric vehicle 100 is running. The series of processes are realized by the processor 102 executing program 104.

[0069] According to the flow shown in Figure 8, first, in step S101, it is determined whether or not the virtual engine brake is active. If the virtual engine brake is not active, the series of processes ends.

[0070] In step S101, the control device 101 may determine whether the electric vehicle 100 is in a virtual engine brake usage scenario, such as when it is driving on a mountain road with a continuous downhill slope, rather than simply determining whether the virtual engine brake is operating temporarily. A virtual engine brake usage scenario, as used here, is a scenario in which the virtual engine brake is expected to be used continuously to a certain extent. The control device 101 may determine that the electric vehicle 100 is in a virtual engine brake usage scenario if the virtual engine brake has been operating continuously for a predetermined time or longer, or if the frequency of the virtual engine brake operating within a certain period of time is greater than or equal to a predetermined frequency.

[0071] If virtual engine braking is active, step S102 is executed. In step S102, it is determined whether the charge acceptance amount of battery 2 is less than a predetermined amount S1. The predetermined amount S1 is the lower limit of the charge acceptance amount that allows virtual engine braking to be activated even when the virtual shift position is 1st gear. The control device 101 obtains the charge acceptance amount from the signal input from the battery management system 10. If the charge acceptance amount is greater than or equal to the predetermined amount S1, the series of processes ends.

[0072] If the amount of charge accepted is less than a predetermined amount S1, step S103 is executed. In step S103, it is determined whether the amount of charge accepted is less than a predetermined amount S2. The predetermined amount S2 is the lower limit of the amount of charge accepted that can activate the virtual engine brake when the virtual shift position is 2nd gear or higher. The predetermined amount S2 is less than the predetermined amount S1.

[0073] If the amount of charge received is equal to or greater than a predetermined amount S2, step S104 is performed. In step S104, the driver is notified to select a shift position of 2nd gear or higher. The notification is made by the HMI 20 displaying the selectable shift positions on the touch panel display. Alternatively, an audio notification may be made via the in-vehicle speaker 21.

[0074] On the other hand, if the amount of charge accepted is less than a predetermined amount S2, step S105 is executed. In step S105, it is determined whether the amount of charge accepted is less than a predetermined amount S3. The predetermined amount S3 is the lower limit of the amount of charge accepted that can activate the virtual engine brake when the virtual shift position is 4th gear or higher. The predetermined amount S3 is less than the predetermined amount S2.

[0075] If the amount of charge received is equal to or greater than a predetermined amount S3, step S106 is performed. In step S106, the driver is notified to select a shift position of 4th gear or higher. The notification is given either visually or audibly.

[0076] On the other hand, if the amount of charge received is less than a predetermined amount S3, step S107 is performed. In step S107, the driver is notified to shift to 6th gear. The notification is given either visually or audibly.

[0077] Thus, when the electric vehicle 100 is in manual mode and deceleration is being performed by virtual engine braking, it prompts the driver to select a shift position corresponding to the amount of charge being received. More specifically, the electric vehicle 100 determines whether the current amount of charge received is less than the threshold amount set for each shift position. If the current amount of charge received is less than the threshold set for any shift position, it notifies the driver to select a shift position that is an upshift position from that shift position. At this time, if there are multiple selectable shift positions, as in steps S104 and S106 above, the driver is notified of all of these shift positions. Note that thresholds for each shift position do not necessarily need to be set for all shift positions. The above example describes a case where three stages of notification are given prompting the selection of a shift position of 2nd gear or higher, 4th gear or higher, and 6th gear. Alternatively, the notifications about selectable shift positions may switch more finely than in the above example. That is, in addition to the above notifications, notifications may be given prompting the driver to select a shift position of 3rd gear or higher, or a shift position of 5th gear or higher.

[0078] 6-4. Effects According to the above process, if the charge level of battery 2 decreases, the driver will be notified to keep the virtual shift position on the upshift side. By selecting the upshift shift position, the strength and frequency of use of the virtual engine brake will decrease, making it possible to reproduce the virtual engine brake even when the charge level is low. In this way, even when the charge level of battery 2 decreases, it is possible to continue using manual mode without compromising the feel of operating a manual transmission internal combustion engine. This can increase the satisfaction of drivers who want to experience the operation of a manual transmission internal combustion engine that is closer to the real thing. It is particularly effective in situations where a large amount of regenerative power is expected to be generated by using the virtual engine brake frequently, such as on downhill slopes.

[0079] 6-5. Second example of processing Figure 9 is a flowchart showing another example of the processing performed by the control device 101. The series of processes shown in Figure 9 are repeatedly executed at a predetermined control cycle, for example, while the electric vehicle 100 is running. The series of processes are realized by the processor 102 executing program 104.

[0080] According to the flow shown in Figure 9, first, in step S201, it is determined whether or not the virtual engine brake is active. If the virtual engine brake is not active, the series of processes ends.

[0081] In step S201, the control device 101 may determine whether the electric vehicle 100 is in a virtual engine braking scene. In this case, if it is not in a virtual engine braking scene, the series of processes ends, and if it is in a virtual engine braking scene, the process proceeds to step S202.

[0082] If virtual engine braking is active, step S202 is executed. In step S202, it is determined whether the amount of charge accepted by battery 2 is less than a predetermined amount. This predetermined amount may be the same as the predetermined amount S1 in step S102, or it may be less. If the amount of charge accepted is equal to or greater than the predetermined amount, the series of processes ends.

[0083] The determination in step S202 may be made based on the State of Operations (SOC). In this case, if the SOC is less than or equal to a predetermined percentage, the process ends; if the SOC is greater than the predetermined percentage, the process proceeds to step S203.

[0084] If the amount of charge received is less than a predetermined amount, step S203 is performed. In step S203, the control device 101 requests the driver not to downshift. For example, the control device 101 displays a message such as "Downshifting is restricted" on the HMI 20.

[0085] Thus, the control device 101 may request the driver not to downshift if the amount of charge received falls below a predetermined amount. In this case as in the first example, by keeping the virtual shift position on the upshift side, the strength and frequency of the virtual engine brake are reduced, and it becomes possible to reproduce engine braking by regenerative braking even with a small amount of charge received. In this way, it is possible to maintain a sense of operation similar to that of operating a real manual transmission internal combustion engine, regardless of the amount of charge received.

[0086] 6-6. Variations In the flow chart of Figure 9, multiple thresholds may be set for the amount of charge accepted, and a minimum acceptable shift position may be set for each threshold. For example, for the first threshold of the amount of charge accepted, the minimum shift position may be set to 4th gear, and if the amount of charge accepted is less than the first threshold, the system may be required not to downshift to 3rd gear or lower. Alternatively, for the second threshold, which is smaller than the first threshold, the minimum shift position may be set to 3rd gear, and if the amount of charge accepted is less than the second threshold, the system may be required not to downshift to 2nd gear or lower.

[0087] In step S202 of the flow in Figure 9, it may be determined whether or not there is an abnormality in battery 2. If there is no abnormality in battery 2, the series of processes ends; if there is an abnormality in battery 2, the process proceeds to step S203. When an abnormality occurs in battery 2, battery 2 may not be able to accept regenerative power. In such cases, by prompting the driver to keep the virtual shift position on the upshift side, the frequency of use of virtual engine braking can be reduced, and the feeling of operation similar to that of a real manual transmission internal combustion engine can be maintained.

[0088] Furthermore, the control device 101 may pre-decrease the amount of charge the battery 2 accepts in accordance with the predicted amount of regenerative power generated. For example, the control device 101 communicates with the navigation system to obtain the planned route of the electric vehicle 100 in advance. If the planned route of the electric vehicle 100 includes a section with continuous downhill slopes, the control device 101 may discharge the battery 2 to reduce its charge before reaching the section with continuous downhill slopes. [Explanation of symbols]

[0089] 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 Shift position sensor, 15 Paddle shift switch, 16 Clutch pedal stroke sensor, 21 In-car speaker, 22 Accelerator pedal, 23 Brake pedal, 24 Simulated H-type shifter, 25 Simulated paddle shifter, 26 Simulated clutch pedal, 100 Electric vehicle, 101 Control unit, 102 Processor, 103 Memory, 104 Program, 105 Data

Claims

1. An electric vehicle having an electric motor as its driving source, Driving control members used for driving the electric vehicle, A simulated gear shift operating member that mimics the operating member used for shifting gears in a manually operated internal combustion engine, A control device that controls the electric vehicle in response to the operation of the driving operation member, The vehicle comprises an onboard battery for charging the electrical energy generated when the regenerative braking of the electric vehicle is activated, The control device is The system executes a control mode in which the operation of the simulated gear shifting control member is associated with the torque of the electric motor, based on the driver's selection. When the above control mode is executed, Determining a virtual shift position based on the operation of the aforementioned simulated gear shift operating member, When the electric vehicle is in motion and there is no accelerator input, regenerative braking is activated with a strength corresponding to the virtual shift position. The system is configured to notify the driver of the electric vehicle of the shift position corresponding to the charge acceptance amount of the onboard battery. An electric vehicle characterized by the following features.

2. In the electric vehicle according to claim 1, A threshold for the amount of charge to be accepted is set for each of the aforementioned virtual shift positions. The control device is During the execution of the control mode, while regenerative braking of a strength corresponding to the virtual shift position is in operation, it is determined whether the amount of charge received is less than the threshold, If the amount of charge received is less than a threshold set for any of the shift positions, the system is configured to notify the driver of a shift position that is an upshift position relative to any of the shift positions. An electric vehicle characterized by the following features.

3. In the electric vehicle according to claim 2, The control device is configured to notify the driver of the multiple shift positions if the shift position on the upshift side of any of the shift positions includes multiple shift positions. An electric vehicle characterized by the following features.

4. In the electric vehicle according to claim 1, The control device is During the execution of the control mode, while regenerative braking of a strength corresponding to the virtual shift position is in operation, it is determined whether the amount of charge received is less than a predetermined amount. The system is configured to perform the following actions: if the amount of charge received is less than the predetermined amount, it requests the driver not to downshift. An electric vehicle characterized by the following features.

5. In the electric vehicle according to claim 4, The control device is The system is configured to determine that the amount of charge received is less than the predetermined amount if the charge level of the vehicle battery is above a predetermined percentage, or if there is an abnormality in the vehicle battery. An electric vehicle characterized by the following features.

6. In an electric vehicle according to any one of claims 1 to 5, The aforementioned driving operation member includes an accelerator pedal, The aforementioned pseudo-speed shifting operating member is A pseudo-H-type shifter that simulates the H-type shifter of a manual transmission, Includes a simulated clutch operating device that mimics a clutch operating device. An electric vehicle characterized by the following features.

7. In the electric vehicle according to claim 6, The control device is configured to change the torque of the electric motor in the control mode according to the shift position selected by the pseudo-H type shifter, the amount of operation of the pseudo-clutch operating device, and the amount of operation of the accelerator pedal. An electric vehicle characterized by the following features.

8. In an electric vehicle according to any one of claims 1 to 5, The aforementioned driving operation member includes an accelerator pedal, The aforementioned simulated gear shifting operating member includes a simulated sequential shifter that mimics the sequential shifter of a manual transmission. An electric vehicle characterized by the following features.

9. In the electric vehicle according to claim 8, The control device is configured to change the torque of the electric motor in the control mode according to the shift position selected by the pseudo-sequential shifter and the amount of operation of the accelerator pedal. An electric vehicle characterized by the following features.

10. In an electric vehicle according to any one of claims 1 to 5, The aforementioned driving operation member includes an accelerator pedal, The aforementioned simulated gear shifting operating member includes a simulated H-shaped shifter that mimics the H-shaped shifter of a manual transmission. An electric vehicle characterized by the following features.

11. In the electric vehicle according to claim 10, The control device is configured to change the torque of the electric motor in the control mode according to the shift position selected by the pseudo-H-type shifter and the amount of operation of the accelerator pedal. An electric vehicle characterized by the following features.

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