Electric vehicles and programs

Abstract

This improves the drivability of electric vehicles when the driver operates the shifter. [Solution] According to one embodiment, an electric vehicle includes a shifter and a control device that can be operated by a driver. The control device is configured to perform multiple types of automatic drive force control that change the drive force independently of the driver input while performing manual drive force control that changes the drive force in response to the driver input. Manual drive force control includes a first mode in which the driver input includes the operation of the shifter and the operation of the shifter can switch the output characteristics of the electric motor in multiple stages, and a second mode in which the driver input does not include the operation of the shifter. Multiple types of automatic drive force control include a first type of automatic drive force control that operates when driving in the first mode and also when driving in the second mode, and a second type of automatic drive force control that does not operate when driving in the first mode but operates when driving in the second mode.

Description

Technical Field

[0001] The present disclosure relates to an electric vehicle that travels by a driving force generated by a motor, and more particularly to an electric vehicle provided with a shifter that can be operated by a driver. The present disclosure also relates to a program for an electric vehicle provided with a shifter that can be operated by a driver.

Background Art

[0002] Patent Document 1 discloses a technique of providing an electric vehicle with a shifter and changing the output characteristics of an electric motor in multiple stages in response to an operation of the shifter. According to this technique, a driver can enjoy a driving feeling similar to that of a vehicle with a manual transmission (hereinafter referred to as an MT vehicle) in an electric vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric vehicle, as a function of supporting a driver's operation, a plurality of types of automatic driving force controls that change the driving force regardless of an input from the driver are implemented. However, if an unintended driving force control is executed, there is a risk that a driver who wants to enjoy driving by operating a shifter may feel that the driving ability has decreased.

[0005] The present disclosure has been made in view of the above problems. One object of the present disclosure is to improve the driving ability of a driver when the driver operates a shifter to drive an electric vehicle.

Means for Solving the Problems

[0006] This disclosure provides an electric vehicle for achieving the above objective. An electric vehicle according to one embodiment of this disclosure is an electric vehicle that runs on a driving force generated by a motor and comprises a shifter that can be operated by a driver and a control device. The control device is configured to perform multiple types of automatic driving force control that change the driving force independently of the driver input while performing manual driving force control that changes the driving force in response to the driver input. Here, the manual driving force control includes a first mode in which the driver input includes the operation of the shifter and the motor output characteristics can be switched in multiple stages by the operation of the shifter, and a second mode in which the driver input does not include the operation of the shifter. The multiple types of automatic driving force control include a first type of automatic driving force control that operates when driving in the first mode and also when driving in the second mode, and a second type of automatic driving force control that does not operate when driving in the first mode but operates when driving in the second mode.

[0007] Furthermore, this disclosure provides a program for achieving the above objectives. One embodiment of this disclosure is a program for an electric vehicle equipped with a driver-operable shifter, and is configured to cause an on-board computer to execute multiple types of automatic drive force control that change the drive force independently of driver input while manual drive force control is being performed, which changes the drive force in response to driver input. Here, the manual drive force control includes a first mode in which the driver input includes shifter operation and the motor output characteristics can be switched in multiple stages by shifter operation, and a second mode in which the driver input does not include shifter operation. Furthermore, the multiple types of automatic drive force control include a first type of automatic drive force control that operates during operation in the first mode and also during operation in the second mode, and a second type of automatic drive force control that does not operate during operation in the first mode but operates during operation in the second mode. [Effects of the Invention]

[0008] According to this disclosure, by switching between the activation / deactivation of multiple types of automatic drive force control depending on the mode of manual drive force control, the drivability when the driver operates the shifter to drive the electric vehicle can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram showing the configuration of the power control system of an electric vehicle according to this embodiment. [Figure 2] Figure 2 shows examples of the engine model, clutch model, and transmission model that make up a vehicle model. [Figure 3] Figure 3 is a flowchart showing a first example of how to determine whether the automatic drive force control is activated or deactivated. [Figure 4] Figure 4 is a flowchart showing a second example of how to determine whether the automatic drive force control is activated or deactivated. [Figure 5] Figure 5 is a block diagram showing a modified configuration of the power control system of an electric vehicle. [Modes for carrying out the invention]

[0010] Figure 1 is a block diagram showing the configuration of the power control system of the electric vehicle 10 according to this embodiment. The electric vehicle 10 is equipped with an electric motor 44, a battery 46, and an inverter 42. The electric motor 44 is the power unit for driving. The battery 46 stores the electrical energy that drives the electric motor 44. In other words, the electric vehicle 10 is a battery electric vehicle (BEV) that runs on the electrical energy stored in the battery 46. The inverter 42 converts the DC power input from the battery 46 during acceleration into driving power for the electric motor 2. The inverter 42 also converts the regenerative power input from the electric motor 44 during deceleration into DC power and charges the battery 46.

[0011] The electric vehicle 10 is equipped with an accelerator pedal 22 for the driver to input an acceleration request to the electric vehicle 10. The accelerator pedal 22 is equipped with an accelerator position sensor 32 for detecting the accelerator opening degree.

[0012] The electric vehicle 10 is equipped with paddle shifters 24. The paddle shifters 24 are mounted on the steering wheel or steering column. The paddle shifters 24 include an upshift switch 34u and a downshift switch 34d that determine the operating position. The upshift switch 34u emits an upshift signal when pulled towards the driver, and the downshift switch 36d emits a downshift signal when pulled towards the driver.

[0013] Wheel speed sensors 36 are provided on the wheels 26 of the electric vehicle 10. The wheel speed sensors 36 are used as vehicle speed sensors to detect the vehicle speed of the electric vehicle 10. In addition, a rotational speed sensor 38 is provided on the electric motor 44 to detect its rotational speed.

[0014] The electric vehicle 10 is equipped with a control device 50. The control device 50 controls the electric motor 44 by PWM control of the inverter 42. The control device 50 receives various sensor signals, including signals from the accelerator position sensor 32, upshift switch 34u, downshift switch 34d, wheel speed sensor 36, and rotational speed sensor 38. The control device 50 processes these signals and calculates a motor torque command value for PWM control of the inverter 42.

[0015] The control device 50 is an on-board computer installed in the electric vehicle 10, and more specifically, an ECU. The control device 50 may be a combination of multiple ECUs. The control device 50 includes a manual drive force control unit 52 and an automatic drive force control unit 54. The manual drive force control unit 52 includes a first-mode torque calculation unit 56 and a second-mode torque calculation unit 58. Each unit 52, 54, 56, and 58 may be an ECU function obtained by executing a program stored in memory on a processor, or each may be associated with an independent ECU.

[0016] The manual driving force control unit 52 is a unit that executes manual driving force control for changing the driving force according to an input from the driver. The input from the driver in the manual driving force control includes at least the operation of the accelerator pedal 22. The manual driving force control includes a first mode and a second mode as control modes of the electric motor 44 that takes the operation of the accelerator pedal 22 as an input. The manual driving force control unit 52 switches the control mode between the first mode and the second mode in response to the operation of a mode change switch (not shown).

[0017] The first mode is a control mode for driving the electric vehicle 10 like a MT vehicle. The first mode is programmed to change the output characteristics of the electric motor 44 with respect to the operation of the accelerator pedal 22 according to the upshift operation and downshift operation with respect to the paddle shifter 24. The calculation of the motor torque when the first mode is being executed is performed by the first mode torque calculation unit 56.

[0018] The first mode torque calculation unit 56 includes a vehicle model described later. The vehicle model is a model for calculating the drive wheel torque that should be obtained by the operations of the accelerator pedal 22 and the paddle shifter 24 when assuming that the electric vehicle 10 is a MT vehicle. The first mode torque calculation unit 56 converts the drive wheel torque calculated by the vehicle model into motor torque using the reduction ratio from the output shaft of the electric motor 44 to the drive wheels.

[0019] The second mode is a normal control mode for driving the electric vehicle 10 as a general BEV. The second mode is programmed to continuously change the output of the electric motor 44 according to the operation of the accelerator pedal 22. The second mode is programmed not to accept upshift operations and downshift operations. The calculation of the motor torque when the second mode is being executed is performed by the second mode torque calculation unit 58.

[0020] The second-mode torque calculation unit 58 has a function of calculating the motor torque when controlling the electric motor 44 in the second mode. A motor torque command map is stored in the second-mode torque calculation unit 58. The motor torque command map is a map that determines the motor torque from the accelerator opening degree and the rotational speed of the electric motor 44. Signals from the accelerator position sensor 32 and signals from the rotational speed sensor 38 are input to each parameter of the motor torque command map. Motor torque corresponding to these signals is output from the motor torque command map. Therefore, in the second mode, even if the driver operates the paddle shifter 24, the operation is not reflected in the motor torque.

[0021] The vehicle model included in the first-mode torque calculation unit 56 will be described with reference to FIG. 2. As shown in FIG. 2, the vehicle model is composed of an engine model 561, a clutch model 562, and a transmission model 563. Note that the engine, clutch, and transmission virtually realized by the vehicle model are referred to as a virtual engine, a virtual clutch, and a virtual transmission, respectively. In the engine model 561, the virtual engine is modeled. In the clutch model 562, the virtual clutch is modeled. In the transmission model 563, the virtual transmission is modeled.

[0022] Engine model 561 calculates virtual engine speed and virtual engine output torque. Virtual engine speed is calculated from wheel speed, overall reduction ratio, and virtual clutch slip ratio. Virtual engine output torque is calculated from virtual engine speed and accelerator opening. As shown in Figure 2, a map is used to calculate virtual engine output torque, which defines the relationship between accelerator opening Pap, virtual engine speed Ne, and virtual engine output torque Teout. In this map, virtual engine output torque Teout is given for each accelerator opening Pap relative to virtual engine speed Ne. The torque characteristics shown in Figure 2 can be set to those of a gasoline engine, or to those of a diesel engine. Furthermore, it can be set to those of a naturally aspirated engine, or to those of a turbocharged engine.

[0023] The clutch model 562 calculates the torque transmission gain. The torque transmission gain is a gain used to calculate the degree of torque transmission by the virtual clutch according to the virtual clutch opening. The virtual clutch opening is normally 0%, and temporarily opens to 100% in conjunction with the switching of the virtual gear stage of the virtual transmission. The clutch model 562 has a map as shown in Figure 2. In this map, a torque transmission gain k is given for the virtual clutch opening Pc. In Figure 2, Pc0 corresponds to the position where the virtual clutch opening Pc is 0%, and Pc3 corresponds to the position where the virtual clutch opening Pc is 100%. The range from Pc0 to Pc1 and the range from Pc2 to Pc3 are dead zones where the torque transmission gain k does not change with respect to the virtual clutch opening Pc. The clutch model 562 calculates the clutch output torque using the torque transmission gain. The clutch output torque is the torque output from the virtual clutch. The clutch model 562 also calculates the slip ratio. The slip ratio is used to calculate the virtual engine speed in the engine model 561. To calculate the slip ratio, a map can be used in which the slip ratio is assigned to a virtual clutch opening, similar to the torque transmission gain.

[0024] Transmission model 563 calculates the gear ratio. The gear ratio is determined by the virtual gear stage in the virtual transmission. The virtual gear stage is increased by one step when the paddle shifter 24 is operated upshift, and the virtual gear stage is decreased by one step when the paddle shifter 24 is operated downshift. Transmission model 563 has a map as shown in Figure 2. In this map, the gear ratio r is given to the virtual gear stage GP such that the larger the virtual gear stage GP, the smaller the gear ratio r becomes. Transmission model 563 calculates the transmission output torque using the gear ratio obtained from the map and the clutch output torque. The transmission output torque changes discontinuously according to the gear ratio change.

[0025] The vehicle model calculates the drive wheel torque using a predetermined reduction ratio. The reduction ratio is a fixed value determined by the mechanical structure from the virtual transmission to the drive wheels. The value obtained by multiplying the reduction ratio by the gear ratio is the aforementioned overall reduction ratio. The vehicle model calculates the drive wheel torque from the transmission output torque and the reduction ratio. The motor torque in manual mode is calculated by multiplying the calculated drive wheel torque by the reduction ratio from the output shaft of the electric motor 44 to the drive wheels.

[0026] Returning to Figure 1, let's explain the automatic drive force control unit 54. The automatic drive force control unit 54 is a unit that performs multiple types of automatic drive force control, which changes the drive force regardless of the input from the driver. Automatic drive force control is classified into Type 1 automatic drive force control and Type 2 automatic drive force control.

[0027] Type 1 automatic drive force control includes, for example, wheel slip suppression control and skid suppression control. Type 1 automatic drive force control is a control related to vehicle stability. Type 1 automatic drive force control can also be defined as a control related to behavior management during driving, or as a control that optimizes operation based on vehicle operation and environmental conditions. Furthermore, Type 1 automatic drive force control can also be defined as a control with brake coordination.

[0028] Type 2 automatic drive force control includes, for example, DMD control, climbing control, descending control, and dynamic G control. DMD control is a technology that improves the driving feel by estimating the driver's mindset and switching vehicle control accordingly, thereby bringing the vehicle behavior closer to what the driver desires. Based on empirical rules, the trajectory of the friction circle calculated from the vehicle's longitudinal and lateral acceleration has the characteristic that in situations where the driving feel is good, the operation follows the friction circle, and the radius of the friction circle increases as the driving becomes more sporty. In the DMD control of the electric vehicle 10, the deceleration when the accelerator is released in D range is controlled based on the driver's mindset. Climbing control is a technology that reduces the amount of accelerator operation by the driver and achieves stable vehicle behavior by correcting the driving force requested by the driver according to the gradient when climbing a hill. Descending control is a technology that switches the deceleration force when the accelerator is released in D range according to the gradient when descending a hill. Dynamic G control is a technology that reads the driver's acceleration intention from the driver's accelerator operation speed and changes the vehicle speed-acceleration characteristics to achieve a seamless feeling of acceleration as the vehicle speed increases. As illustrated above, Type 2 automatic drive force control is not a control related to vehicle stability, but rather a control aimed at improving the quality of the driver's driving. If Type 1 automatic drive force control is considered a basic control, then Type 2 automatic drive force control can be defined as a value-added control.

[0029] Automatic drive force control operates automatically while manual drive force control is being performed. However, there are differences in the determination of whether to activate or deactivate it between Type 1 and Type 2 automatic drive force control. Figure 3 is a flowchart showing the first example of the determination of whether to activate or deactivate automatic drive force control. The determination shown in this flowchart is made by the control device 50, specifically by the automatic drive force control unit 54.

[0030] In step S110, the control device 50 determines whether the currently executed manual drive force control is in the first mode. If the manual drive force control is in the first mode, the control device 50 executes steps S120 and S130. In step S120, the control device 50 activates the first type of automatic drive force control. In step S130, the control device 50 deactivates the second type of automatic drive force control. In other words, in the first mode, the first type of automatic drive force control is activated, but the second type of automatic drive force control is not.

[0031] On the other hand, when manual drive force control is in the second mode, the control device 50 performs steps S140 and S150. In step S140, the control device 50 activates the first type of automatic drive force control. In step S150, the control device 50 also activates the second type of automatic drive force control. In other words, in the second mode, both the first type of automatic drive force control and the second type of automatic drive force control are activated.

[0032] As described above, by determining whether or not to activate the automatic drive force control, the drivability when the driver operates the electric vehicle 10 by operating the paddle shifter 24 can be improved. More specifically, in situations where the driver desires to drive actively by operating the paddle shifter 24, activating only the first type of automatic drive force control, which is a basic control that affects vehicle stability, can increase the degree of freedom of vehicle control by the driver themselves. On the other hand, in situations where the driver desires the smooth driving characteristic of electric vehicles, activating not only the first type of automatic drive force control but also the second type of automatic drive force control can improve the quality of vehicle control performed automatically by the electric vehicle 10.

[0033] Figure 4 is a flowchart showing a second example of how to determine whether the automatic drive force control is activated or deactivated. In this flowchart, the same processes as in the first example are given the same numbers.

[0034] The second example differs from the first example in how it handles the case where manual drive force control is in the first mode. When manual drive force control is in the first mode, the control device 50 determines in step S122 whether the driver has specified that the first type of automatic drive force control should not be activated. As explained in the first example, the first type of automatic drive force control is a control that operates regardless of whether it is in the first or second mode. However, if the driver wants to steer the vehicle more freely, the first type of automatic drive force control may get in the way. Therefore, in the second example, the driver is given the option to choose whether to activate or deactivate the first type of automatic drive force control in the first mode.

[0035] If the driver specifies in step S122 that some or all of the Type 1 automatic drive force control be deactivated, the control device 50 executes step S124. In step S124, the control device 50 deactivates only the specified automatic drive force control among the Type 1 automatic drive force control. For example, if the driver specifies skid suppression control, the control device 50 deactivates skid suppression control in the first mode.

[0036] On the other hand, if the driver does not specify in step S122 that the first type of automatic drive force control be deactivated, the control device 50 executes step S126. In step S126, the control device 50 activates all first type of automatic drive force control.

[0037] Next, in step S132, the control device 50 determines whether the driver has specified the activation of the second type of automatic driving force control. As explained in the first example, the second type of automatic driving force control is activated in the second mode but not in the first mode. However, some drivers want to operate the vehicle more easily, and even the same driver may want to operate the vehicle more easily depending on the situation or their mood. Therefore, in the second example, the driver is given the option to choose whether to activate or deactivate the second type of automatic driving force control in the first mode.

[0038] If the driver specifies the activation of some or all of the Type 2 automatic driving force control in step S132, the control device 50 executes step S134. In step S134, the control device 50 activates only the specified automatic driving force control from the Type 2 automatic driving force control. For example, if hill climbing control is specified, the control device 50 activates hill climbing control in the first mode.

[0039] On the other hand, if the driver does not specify the activation of the second type of automatic drive force control in step S132, the control device 50 executes step S136. In step S136, the control device 50 deactivates all second type of automatic drive force control.

[0040] As described above, by determining whether the automatic drive force control is activated or deactivated, the drivability when the driver operates the paddle shifter 24 to drive the electric vehicle 10 can be further improved.

[0041] Finally, a modified configuration of the power control system of the electric vehicle 10 will be explained using Figure 5. In this modified configuration, an H-shaped shifter 62 is provided in place of the paddle shifter 24. The H-shaped shifter 62 is equipped with a shift position sensor 72 that detects which shift gate the shift lever is in, that is, which shift position has been selected. The shift position sensor 72 emits a signal indicating the selected shift position.

[0042] In this modified version, a clutch pedal 64 is provided. The clutch pedal 64 is equipped with a clutch position sensor 74 for detecting the clutch opening degree, which is the amount of operation of the pedal. In this modified version, the clutch opening degree detected by the clutch position sensor 74 is used to calculate the torque transmission gain using the clutch model 562. In other words, in the first mode of this modified version, the output characteristics of the electric motor 44 are switched by operating the H-type shifter 62 and the clutch pedal 64. On the other hand, in the second mode, whether the driver operates the H-type shifter 62 or the clutch pedal 64, the operation does not affect the motor torque. [Explanation of Symbols]

[0043] 10 Electric vehicle, 22 Accelerator pedal, 24 Paddle shifter, 44 Electric motor, 46 Battery, 50 Control unit, 62 H-type shifter, 64 Clutch pedal

Claims

1. An electric vehicle that is driven by the driving force generated by an electric motor, A shifter that can be operated by the driver, The control device is configured to perform multiple types of automatic drive force control, which change the drive force regardless of the input from the driver, while manual drive force control is being performed, which changes the drive force in response to the input from the driver. The manual drive force control is, A first mode includes the operation of the shifter as input from the driver, and the output characteristics of the electric motor can be switched in multiple stages by operating the shifter. A second mode includes the input from the driver which does not include the operation of the shifter, The aforementioned multiple types of automatic driving force control are: A first type of automatic driving force control that operates during operation in the first mode and also during operation in the second mode, Includes a second type of automatic drive force control that does not operate during operation in the first mode and operates during operation in the second mode. An electric vehicle characterized by the following features.

2. In the electric vehicle according to claim 1, The first type of automatic drive force control includes an automatic drive force control that is selected by the driver and does not operate during operation in the first mode. An electric vehicle characterized by the following features.

3. In the electric vehicle according to claim 1, The second type of automatic drive force control includes an automatic drive force control that is selected by the driver and operates during operation in the first mode. An electric vehicle characterized by the following features.

4. In an electric vehicle according to any one of claims 1 to 3, The system further includes a clutch pedal that can be operated by the aforementioned driver, The first mode includes the operation of the clutch pedal as input from the driver, and the output characteristics of the electric motor can be switched in multiple stages by operating the shifter and the clutch pedal. The second mode does not include the operation of the clutch pedal in the input from the driver. An electric vehicle characterized by the following features.

5. A program for an electric vehicle that includes a driver-operable shifter, The in-vehicle computer is configured to perform multiple types of automatic drive force control, which change the drive force regardless of the driver's input, while manual drive force control is being performed, which changes the drive force in response to the driver's input. The manual drive force control is, The input from the driver includes the operation of the shifter, and the operation of the shifter enables switching the output characteristics of the electric motor in multiple stages, in a first mode. A second mode includes the input from the driver which does not include the operation of the shifter, The aforementioned multiple types of automatic driving force control are: A first type of automatic driving force control that operates during operation in the first mode and also during operation in the second mode, Includes a second type of automatic drive force control that does not operate during operation in the first mode and operates during operation in the second mode. A program characterized by the following features.

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