Electric vehicle

Abstract

The present disclosure relates to an electric vehicle. An electric vehicle configured to use an electric motor as a power device for traveling is provided with a control device configured to control the electric vehicle and a shift lever. The control device is configured to switch between an automatic mode in which traveling as a general electric vehicle is performed and a manual mode in which a virtual gear shift operation based on the shift lever is accepted and traveling in which manual transmission driving is simulated is performed, in accordance with an operation of a driver of the electric vehicle, and the control device is configured to switch the regenerative braking force of the electric motor in accordance with the virtual gear shift operation in the manual mode.

Description

Technical Field

[0001] This disclosure relates to techniques for controlling electric vehicles that have an electric motor as a drive source. Background Technology

[0002] Japanese Patent Application Publication No. 2024-157909 discloses an electric vehicle that uses an electric motor as its power source. This electric vehicle is equipped with a paddle shifter and a motor control device. The paddle shifter includes upshift, downshift, and mode switching operations. The motor control device receives the mode switching operations and switches between manual and automatic modes. Automatic mode is used to drive the electric vehicle as a regular electric vehicle. In manual mode, the manual shifting action of a manual transmission (MT) vehicle is simulated.

[0003] Electric vehicles equipped with manual and automatic modes are known. In manual mode, driving operations similar to those of a manual transmission (MT) vehicle are possible, while in automatic mode, the vehicle operates as a typical electric vehicle. In such electric vehicles, the driver can switch between manual and automatic modes. Furthermore, electric vehicles are known to have a function that changes deceleration by varying the magnitude of the regenerative braking force of the electric motor. However, the combination of electric vehicles equipped with manual and automatic modes with a function that selects the magnitude of the regenerative braking force has not been sufficiently studied to date. Summary of the Invention

[0004] This disclosure discloses an electric vehicle configured to use an electric motor as its driving power unit. The electric vehicle includes a control device and a gear shifter. The control device is configured to control the electric vehicle. The control device is configured to switch between an automatic mode and a manual mode in response to the driver's operation. In automatic mode, the vehicle operates as a normal electric vehicle. In manual mode, it accepts virtual gear shifting operations based on the gear shifter and simulates driving with a manual transmission. The control device is configured to switch the regenerative braking force of the electric motor in response to the virtual gear shifting operations in manual mode.

[0005] In the above scheme, the regenerative characteristics of the electric motor in manual mode may also be different from those in automatic mode.

[0006] In the above scheme, the automatic mode may also include multiple drive modes with different intensities of the regenerative braking force.

[0007] In the above scheme, the control device may also be configured to set the drive mode to the previously set drive mode when the control mode is switched from the manual mode to the automatic mode.

[0008] In the above scheme, the control device may also be configured to switch the drive mode in accordance with the operation of the gear shifter.

[0009] In the above-described scheme, the gear shifter may also be a paddle shifter consisting of a pair of paddles. Alternatively, the control device may be configured to, in manual mode, upshift a virtual gear in response to the operation of one paddle of the paddle shifter, and downshift the virtual gear in response to the operation of the other paddle of the paddle shifter. Alternatively, the control device may be configured to, in automatic mode, reduce the regenerative braking force in response to the operation of one paddle, and increase the regenerative braking force in response to the operation of the other paddle.

[0010] The electric vehicle disclosed herein has a manual mode and an automatic mode. In manual mode, the regenerative braking force of the electric motor is switched in accordance with the virtual gear shifting operation. According to the disclosed solution, by reproducing the switching of braking force of a manual transmission (MT) vehicle corresponding to the gear shifting operation on the regenerative side, a sense of realism, as if driving an actual MT vehicle, can be enhanced. Attached Figure Description

[0011] The features, advantages, and technical and industrial importance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in the drawings:

[0012] Figure 1 This is a diagram showing the structure of the control system of the electric vehicle according to this embodiment.

[0013] Figure 2 This is a block diagram illustrating the functions of the BEV-ECU.

[0014] Figure 3 It is a graph showing the virtual transmission torque specified for each gear in manual mode.

[0015] Figure 4 It is a graph showing the regenerative braking force when switching gears in manual mode.

[0016] Figure 5 It is a graph showing the intensity of regenerative braking force in multiple driving modes. Detailed Implementation

[0017] The embodiments of this disclosure will be described with reference to the accompanying drawings.

[0018] 1. Structure of the control system of an electric vehicle

[0019] Figure 1 This diagram illustrates the structure of the control system of an electric vehicle 100 according to an embodiment of the present disclosure. The electric vehicle 100 is a battery electric vehicle (BEV) that operates using electrical energy stored in a battery. As controlled objects, the control system of the electric vehicle 100 includes an electric motor 10 as a power unit for driving, an instrument panel 11 that provides visual information to the driver, a buzzer 12 that provides auditory information to the driver, and a speaker 13. Furthermore, as control devices for controlling these controlled objects, the electric vehicle 100 includes multiple ECUs (Electronic Control Units) and input devices that input instructions from the driver to these ECUs. The ECUs include a BEV (Battery Electric Vehicle) ECU 30, an SBW (Shift By Wire) ECU 31, a MM (Multi Media) ECU 32, an MG (Motor Generator) ECU 33, an instrument panel ECU 34, and an ASC (Active Sound Control) ECU 35. The input interface includes a gear selector 20, a control mode switch 21, an accelerator pedal 22, a paddle shifter 23, and a multimedia system 24.

[0020] The gear selector 20 is an input interface for the driver to select a gear. Available gears include, for example, parking, reverse, neutral, and drive. When the driver operates the gear selector 20, a signal s1 corresponding to the position of the operating component of the gear selector 20 is output from the gear selector 20 to the SBW-ECU 31. The SBW-ECU 31 determines the gear based on the input signal s1 and outputs a signal s2 containing information about the selected gear to the BEV-ECU 30.

[0021] The control mode switch 21 is an input interface for switching the control mode of the electric vehicle 100 between automatic and manual modes. Automatic mode is the mode in which the electric motor 10 is controlled with normal output characteristics in response to output requests from the driver. Manual mode is the mode in which the electric vehicle 100 operates like a motor vehicle capable of manual transmission (manual transmission vehicle / MT vehicle). In manual mode, the output characteristics of the electric motor 10 can be switched in multiple stages by operating the paddle shifter 23, described later. Furthermore, the control mode switch 21 can be either an alternating switch or a momentary switch. When the driver operates the control mode switch 21, a signal s3 corresponding to the control mode determined by the operation is output from the control mode switch 21 to the BEV-ECU 30.

[0022] The accelerator pedal 22 serves as an input interface for obtaining the amount of pressure applied by the driver when pressing the accelerator pedal 22, which is used as the driver's acceleration request. When the driver presses the accelerator pedal 22, the accelerator pedal travel sensor outputs a signal s4 corresponding to the amount of pressure applied to the BEV-ECU 30.

[0023] The paddle shifter 23 is an input interface consisting of a pair of paddles mounted on the steering wheel or steering column. When the driver pulls a paddle forward, a signal s5 corresponding to the pulled paddle is output from the paddle shifter 23 to the BEV-ECU 30. In manual mode, the paddle shifter 23 becomes an input interface for multi-level gear shifting. However, the electric vehicle 100 does not have a physical transmission. The gears mentioned here are not actual transmission gears, but rather one of the parameters of the physical model used for calculating engine torque (described later). In manual mode, the signal s5 output when the right paddle is pulled is a signal requesting an upshift, and the signal s5 output when the left paddle is pulled is a signal requesting a downshift. On the other hand, in automatic mode, the paddle shifter 23 becomes an input interface for multi-level switching of regenerative braking force intensity. In automatic mode, when the right paddle is pulled, the output signal s5 is a signal requesting a reduction in regenerative braking force, and when the left paddle is pulled, the output signal s5 is a signal requesting a strengthening of regenerative braking force.

[0024] The multimedia system 24 is an input interface with a touchscreen that displays various information such as navigation and audio settings and accepts touch operations from the driver. The driver can make various settings for the electric vehicle 100 through the touchscreen. When the driver operates the touchscreen, a signal s6 corresponding to the operation is output from the multimedia system 24 to the MM-ECU 32. The MM-ECU 32 determines the settings requested by the driver based on the input signal s6. If the driver requests a driving mode setting, the MM-ECU 32 outputs a signal s7 containing information about the driving mode selected by the driver to the BEV-ECU 30. The driving mode can be set in manual mode, and a driving mode that suits the driver's preferences can be selected from multiple driving modes. If the driver requests a setting for the speaker 13 to be turned on / off or adjusted in volume, the MM-ECU 32 outputs a signal s8 containing information about the speaker 13 being turned on / off or adjusted in volume to the ASC-ECU 35.

[0025] The BEV-ECU30 calculates the torque (hereinafter referred to as motor torque) output by the electric motor 10 based on the input signals s2, s3, s4, s5, and s7. However, in addition to these signals, other information, including at least the vehicle speed, is also used in the calculation of the motor torque. The vehicle speed is measured using speed sensors installed at each wheel. The BEV-ECU30 calculates the motor torque using a method corresponding to the control mode determined by signal s3. In automatic mode, the BEV-ECU30 primarily calculates the motor torque based on signal s4 and the vehicle speed. In manual mode, the BEV-ECU30 primarily calculates the motor torque based on signals s4, s5, and s7 and the vehicle speed. Details of the motor torque calculation method in each control mode are described later. The BEV-ECU30 outputs signal s9, which includes information about the calculated motor torque, to the MG-ECU33. The MG-ECU33 generates signal s12 for PWM control of the electric motor 10 based on signal s9 and uses signal s12 to control the electric motor 10.

[0026] The BEV-ECU 30 outputs a signal s10 to the instrument-ECU 34, which includes information to be displayed on the instrument cluster 11 and a buzzer sounding request. The information displayed on the instrument cluster 11 includes, for example, the selected control mode, the gear position when manual mode is selected, and the virtual engine speed. The virtual engine speed is one of the parameters of the physical model used for calculating motor torque in manual mode. The instrument-ECU 34 generates a signal s13 to display this information and uses the signal s13 to control the instrument cluster 11. For example, it outputs a buzzer sounding request to inform the driver when to downshift or upshift. When the signal s10 includes a buzzer sounding request, the instrument-ECU 34 generates a signal s14 and uses the signal s14 to sound the buzzer 12.

[0027] The BEV-ECU30 outputs signal s11, which includes information used to generate a simulated engine sound, to the ASC-ECU35. The simulated engine sound is a simulation of the exhaust sound of an engine vehicle emitted from speaker 13 when manual mode is selected. Information used to generate the simulated engine sound includes, for example, virtual engine speed, virtual engine torque, and virtual gear. Virtual engine torque is one of the parameters of the physical model used for calculating motor torque in manual mode. Based on this information, the ASC-ECU35 generates signal s15 to produce the simulated engine sound and uses signal s15 to control speaker 13.

[0028] 2. Functions of BEV-ECU

[0029] Next, the functions of BEV-ECU30 will be described. BEV-ECU30 has at least a processor (processing circuit) and a memory. The memory includes: RAM, which temporarily records data; and ROM, which stores programs executable by the processor and various data associated with the programs. The program consists of multiple instructions. The processor reads the program and data from the memory and executes them, generating signal s9 output to MG-ECU33, signal s10 output to Instrument Cluster-ECU34, and signal s11 output to ASC-ECU35.

[0030] Figure 2 This is a block diagram illustrating the functions of the BEV-ECU 30. The BEV-ECU 30 functions as a control mode switching unit 310, an automatic mode parameter calculation unit 320, and a manual mode parameter calculation unit 330. These functions are implemented by a processor executing one or more programs stored in the memory of the BEV-ECU 30.

[0031] The control mode switching unit 310 switches the control mode relative to the output control of the electric motor 10 from the driver's operation input. The control modes that can be switched by the control mode switching unit 310 are the aforementioned automatic mode and manual mode. The control mode switching unit 310 switches the control mode according to the signal s3 input from the control mode switching switch 21.

[0032] When the control mode is switched to automatic mode using the control mode switching unit 310, the BEV-ECU 30 functions as the automatic mode parameter calculation unit 320. The automatic mode parameter calculation unit 320 performs output control corresponding to the gear selected by the gear selector 20. For example, when the selected gear is D, the automatic mode parameter calculation unit 320 obtains the accelerator opening based on the signal s4 from the accelerator pedal 22 and the vehicle speed based on the signal from a speed sensor (not shown). The automatic mode parameter calculation unit 320 has a motor torque mapping function that uses the accelerator opening and vehicle speed as parameters. By inputting the accelerator opening and vehicle speed into the motor torque mapping function, the automatic mode parameter calculation unit 320 calculates the motor torque generated by the electric motor 10 and outputs a signal s9 containing information about the calculated motor torque to the MG-ECU 33.

[0033] In the aforementioned motor torque mapping, the motor torque is defined as negative when the accelerator opening is zero. That is, when the accelerator opening is zero, the regenerative braking force of the electric motor 10 operates, causing the electric vehicle 100 to decelerate. In automatic mode, the driver can operate the paddle shifter 23 to switch the intensity of the regenerative braking force. At this time, the intensity of the regenerative braking force can be switched either by multiplying the motor torque calculated by the motor torque mapping by a predetermined value, or by preparing multiple motor torque mappings with different regenerative braking forces in advance, or by switching the motor torque mapping to switch the intensity of the regenerative braking force.

[0034] When the control mode is switched to manual mode using the control mode switching unit 310, the BEV-ECU 30 functions as the manual mode parameter calculation unit 330. The manual mode parameter calculation unit 330 performs processing to calculate the drive wheel torque generated by the drive wheels and to calculate the motor torque based on the drive wheel torque.

[0035] The manual mode parameter calculation unit 330 uses a physical model of the engine vehicle to calculate the drive wheel torque. The physical model includes a virtual engine 331 modeled from the engine and a virtual transmission 332 modeled from the transmission capable of manual shifting. Furthermore, the virtual transmission 332 also includes a model of an automatic clutch.

[0036] In the virtual engine 331, the relationship between the virtual engine speed and the virtual engine torque is defined according to each accelerator opening degree. The speed-torque characteristic of the virtual engine 331 can be set to resemble that of a gasoline engine or a diesel engine. Furthermore, the speed-torque characteristic can be set to resemble that of a naturally aspirated engine or a turbocharged engine. The virtual engine speed is calculated based on the virtual gear ratio calculated by the virtual transmission 332, the virtual reduction ratio from the virtual transmission 332 to the drive wheels, and the vehicle speed. The virtual engine torque calculated by the virtual engine 331 is input to the virtual transmission 332.

[0037] In the virtual transmission 332, a virtual gear ratio is set for each gear. For example, when the gears are 1st to 6th, the maximum virtual gear ratio is set for 1st gear, and the virtual gear ratio decreases in the order of 2nd, 3rd, 4th, 5th, and 6th gears. The virtual transmission torque is calculated using the virtual gear ratios calculated by the virtual transmission 332 and the virtual engine torque input from the virtual engine 331. The manual mode parameter calculation unit 330 calculates the drive wheel torque based on the virtual transmission torque and the reduction ratio.

[0038] The manual mode parameter calculation unit 330 calculates the motor torque by multiplying the drive wheel torque by the actual reduction ratio from the output shaft of the electric motor 10 to the drive wheel, and outputs a signal s9 containing the calculated motor torque information to the MG-ECU 33. However, when the electric vehicle 100 has electric motors 10 on both the front and rear wheel sides, the manual mode parameter calculation unit 330 calculates the motor torque of the front electric motor based on the torque distribution from the drive wheel torque to the front wheel, and calculates the motor torque of the rear electric motor based on the torque distribution from the drive wheel torque to the rear wheel.

[0039] 3. Regenerative braking force in manual mode

[0040] In manual mode, the virtual transmission torque is calculated using a physical model of the engine vehicle. In the physical model used by the manual mode parameter calculation unit 330, the relationship between vehicle speed and virtual transmission torque is defined using torque mapping. Figure 3 The diagram illustrates the relationship between vehicle speed and virtual transmission torque at maximum accelerator opening for each virtual gear ratio. Switching between virtual gear ratios corresponds to switching the virtual transmission torque calculated from the torque mapping.

[0041] Furthermore, when the accelerator opening is zero, the virtual transmission torque is negative. This negative virtual transmission torque is reproduced by the regenerative braking force of the electric motor 10. This is equivalent to engine braking in a manual transmission (MT) vehicle. Figure 4The diagram illustrates the relationship between vehicle speed and virtual transmission torque for each virtual gear ratio. When switching virtual gear ratios, the virtual transmission torque calculated based on the torque mapping is switched accordingly. That is, in manual mode, the regenerative braking force of the electric motor 10 is switched in accordance with the virtual gear shifting operation using the paddle shifter 23.

[0042] In manual mode, the regenerative characteristics, i.e., the regenerative braking force for each virtual gear ratio defined by torque mapping, are determined to reproduce the engine braking of a manual transmission (MT) vehicle. On the other hand, the regenerative characteristics of the electric motor 10 in automatic mode do not reproduce the engine braking of an MT vehicle. Therefore, the regenerative characteristics in manual mode differ from those in automatic mode. In manual mode, the control is configured to reproduce the driving characteristics of the electric motor 10 as those of an MT vehicle. Furthermore, by making the regenerative characteristics of the electric motor 10 also reproduce the regenerative characteristics unique to manual mode, which reproduces engine braking, a sense of realism, as if driving an actual MT vehicle, is enhanced.

[0043] Furthermore, in the manual mode parameter calculation unit 330, the torque mapping can be switched according to each virtual gear ratio, and the virtual transmission torque can be calculated based on the torque mapping of each virtual gear ratio. Alternatively, the virtual engine torque can be calculated based on a torque mapping, and the virtual transmission torque can be calculated based on the virtual engine torque and the virtual gear ratio.

[0044] 4. Operating components for switching regenerative braking force

[0045] The paddle shifter 23 is used as an operating component for virtual gear shifting in manual mode and as a deceleration selector for switching the intensity of regenerative characteristics, i.e., deceleration, in automatic mode. By using the paddle shifter 23 in accordance with each mode, the operating components mounted on the electric vehicle 100 can be used effectively without the need for different operating components in manual and automatic modes.

[0046] Furthermore, in automatic mode, the driver can increase the strength of regenerative braking by performing the same downshifting operation as in manual mode, and decrease the strength of regenerative braking by performing the same upshifting operation as in manual mode. In manual transmission (MT) vehicles, engine braking strengthens when the gear is downshifted and weakens when the gear is upshifted. Therefore, in automatic mode, by using the same operation to increase regenerative braking as downshifting in manual mode and the same operation to decrease regenerative braking as upshifting in manual mode, the operation can be easily and intuitively mastered, reducing the risk of misoperation.

[0047] 5. Multiple drive modes

[0048] The automatic mode can also include multiple drive modes with different intensities of regenerative braking force. Furthermore, in automatic mode, the intensity of regenerative braking force can be switched by changing the drive mode in accordance with the driver's operation of the paddle shifter 23.

[0049] exist Figure 5 Examples of multiple drive modes are shown in the graph. The vertical axis of the graph shows the torque of the electric motor 10 that generates regenerative braking force, and the horizontal axis shows the motor speed. There are three drive modes: drive mode 1 to drive mode 3, and the intensity of regenerative braking force is preset according to each drive mode. When the right paddle of the paddle shifter 23, which weakens the regenerative braking force, is pulled, the BEV-ECU 30 shifts to a drive mode with weaker regenerative braking force, and when the left paddle, which strengthens the regenerative braking force, is pulled, it shifts to a drive mode with stronger regenerative braking force.

[0050] The driving modes can also be named according to the situation to provide a reference for the driver. For example, they can be named sequentially from the driving mode with weaker regenerative braking force as Eco mode, Normal mode, and Sport mode. In this way, by defining the regenerative characteristics according to each driving mode, the driver can easily select the intensity of regenerative braking force that matches their preferences and the situation.

[0051] Alternatively, in this scenario, when switching from manual to automatic control mode, the BEV-ECU30 can set the drive mode to the previously set mode. For example, suppose the driver selects sport mode while driving in automatic mode. Then, suppose the driver switches the control mode from automatic to manual mode, and then switches back from manual to automatic mode. In this case, the BEV-ECU30 will set the drive mode to the sport mode previously selected by the driver. This way, even without the driver manually selecting the mode, the drive mode setting that matches the driver's preferences can be inherited.

Claims

1. An electric vehicle configured to use an electric motor as a power unit for driving, characterized in that, The electric vehicle has the following features: A control device configured to control the electric vehicle; and Gear shifter, among which, The control device is configured to switch between automatic and manual modes in response to the operation of the driver of the electric vehicle. In automatic mode, the vehicle is driven as a normal electric vehicle, while in manual mode, it accepts virtual gear shifting operations based on the gear shifter and simulates driving with a manual transmission. The control device is configured to switch the regenerative braking force of the electric motor in the manual mode in accordance with the virtual gear shifting operation.

2. The electric vehicle according to claim 1, characterized in that, The regenerative characteristics of the electric motor in manual mode are different from those in automatic mode.

3. The electric vehicle according to claim 1 or 2, characterized in that, The automatic mode includes multiple drive modes with different intensities of the regenerative braking force.

4. The electric vehicle according to claim 3, characterized in that, The control device is configured to set the drive mode to the previously set drive mode when the control mode is switched from the manual mode to the automatic mode.

5. The electric vehicle according to claim 3, characterized in that, The control device is configured to switch the drive mode in accordance with the operation of the gear shifter.

6. The electric vehicle according to claim 1 or 2, characterized in that, The gear shifter is a paddle shifter consisting of a pair of paddles. The control device is configured to shift a virtual gear up in response to the operation of one of the paddles on the paddle shifter in the manual mode. The control device is configured to downshift the virtual gear in the manual mode in response to the operation of the other paddle of the paddle shifter. The control device is configured to reduce the regenerative braking force in accordance with the operation of one of the paddles in the automatic mode. The control device is configured to increase the regenerative braking force in accordance with the operation of the other party's paddle in the automatic mode.

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