JP7413959B2 - Electric car - Google Patents

Description

The present invention relates to an electric vehicle that uses an electric motor as a driving power device.

An electric motor used as a driving power device in an electric vehicle (EV) has significantly different torque characteristics from an internal combustion engine that has been used as a driving power device in conventional vehicles. Due to differences in the torque characteristics of power plants, CVs require a transmission, whereas EVs generally do not have a transmission. Of course, EVs are not equipped with a manual transmission (MT) that changes the gear ratio manually by the driver. For this reason, there is a big difference in driving sensation between driving a conventional vehicle with an MT (hereinafter also referred to as "MT vehicle") and driving an EV.

On the other hand, the torque of an electric motor can be controlled relatively easily by controlling the applied voltage and magnetic field. Therefore, in an electric motor, by performing appropriate control, it is possible to obtain desired torque characteristics within the operating range of the electric motor. Techniques have been proposed that take advantage of this feature to control the torque of EV vehicles to simulate the torque characteristics unique to MT vehicles.

Patent Document 1 discloses a technique for producing a pseudo shift change in a vehicle in which torque is transmitted to wheels by a drive motor. In this vehicle, the torque of the drive motor is reduced by a set variation amount at a predetermined timing determined by the vehicle speed, accelerator opening degree, accelerator opening speed, or amount of brake depression, and then the torque is increased again at a predetermined time. Variation control is performed. The company claims that this will reduce the sense of discomfort that it gives to drivers who are accustomed to vehicles equipped with stepped transmissions.

Japanese Patent Application Publication No. 2018-166386

However, with the above technology, the timing of torque fluctuation control that simulates a gear shift operation cannot be independently determined by the driver's own operation. In particular, for a driver who is accustomed to driving a manual transmission vehicle, a pseudo-shift operation that does not involve the driver's own manual gear shift operation may give a sense of discomfort to the driver.

In consideration of these circumstances, the inventors of the present application are considering providing an EV with a pseudo shift device and a pseudo clutch pedal so that the EV can provide the driving sensation of a manual transmission vehicle. Of course, these pseudo devices are not simply attached to EVs. The inventors of the present application are considering making it possible to control an electric motor so as to obtain torque characteristics similar to those of an MT vehicle by operating a pseudo shift device and a pseudo clutch pedal.

On the other hand, as a driver, you may want to drive the vehicle like a manual transmission vehicle or as a regular EV, depending on the driving environment or your own mood, for example. One possible way to achieve this request is to prepare two control modes for the electric motor: a control mode that simulates a manual transmission vehicle, and a normal control mode for an EV, and make it possible to switch between them at will. It will be done.

However, in the control mode that simulates an MT vehicle, the torque characteristic simulates that of an internal combustion engine, so the maximum torque is not generated when the vehicle starts. For this reason, in a control mode that simulates a manual transmission vehicle, even though the power device is an electric motor, it is not possible to achieve good acceleration when starting, which is characteristic of EVs.

The present invention was made in view of the above-mentioned problems, and it is possible to obtain the driving feeling of both MT vehicle-like driving and normal EV driving, and when starting, it is possible to perform acceleration peculiar to EV. The aim is to provide electric vehicles that can.

The electric vehicle according to the present invention is an electric vehicle that uses an electric motor as a driving power device, and includes an acceleration pedal, a pseudo clutch pedal, a pseudo shift device, a mode selection switch, and a control device. The mode selection switch is a switch that selects the control mode of the electric motor between a first mode and a second mode. The control device is a device that controls the motor torque output by the electric motor according to the control mode selected by the mode selection switch.

The control device includes a memory and a processor. The memory stores an MT vehicle model and a motor torque command map. The MT vehicle model is a model that simulates the torque characteristics of drive wheel torque in an MT vehicle. The MT vehicle here is a vehicle that has an internal combustion engine whose torque is controlled by operating a gas pedal, and a manual transmission whose gears are changed by operating a clutch pedal and operating a shift device. The MT vehicle model is used in the first mode. The motor torque command map is a map that defines the relationship between the operation amount of the acceleration pedal and the motor torque with respect to the rotational speed of the electric motor. The motor torque command map is used in the second mode.

When controlling the electric motor in the first mode, the processor executes the following first to fifth processes. The first process is a process of accepting the operation amount of the acceleration pedal as an input of the operation amount of the gas pedal for the MT vehicle model. The second process is a process of accepting the operation amount of the pseudo clutch pedal as an input of the operation amount of the clutch pedal for the MT vehicle model. The third process is a process of accepting the shift position of the pseudo shift device as an input of the shift device for the MT vehicle model. The fourth process is a process of calculating the drive wheel torque determined by the operation amount of the acceleration pedal, the operation amount of the pseudo clutch pedal, and the shift position of the pseudo shift device using the MT vehicle model. The fifth process is a process of calculating the motor torque for applying the drive wheel torque to the drive wheels of the host vehicle.

When controlling the electric motor in the second mode, the processor executes the following sixth and seventh processes. The sixth process is a process of invalidating the operation of the pseudo clutch pedal and the operation of the pseudo shift device. The seventh process is a process of calculating the motor torque using a motor torque command map based on the operation amount of the acceleration pedal and the rotational speed of the electric motor.

Further, when the first mode is selected by the mode selection switch, the processor determines whether the gear stage of the MT vehicle model determined by the shift position is less than a predetermined value or the vehicle speed of the own vehicle is less than a predetermined value. If either one of the above conditions holds true, the electric motor is controlled to achieve the motor torque in the second mode.

According to the above configuration, the driver can drive the electric vehicle like a manual transmission vehicle having an internal combustion engine and a manual transmission by selecting the first mode using the mode selection switch. In other words, the driver can operate the clutch pedal and shift device to obtain a driving sensation similar to that of a manual transmission vehicle. Furthermore, by selecting the second mode using the mode selection switch, the driver can drive the electric vehicle with its original performance.

Furthermore, according to the above configuration, even if the first mode is selected by the mode selection switch, the gear stage of the MT vehicle model is less than a predetermined value or the vehicle speed of the host vehicle is less than a predetermined value. If either one of them is true, the electric motor is controlled in the second mode. In other words, when starting the vehicle, acceleration unique to EVs can be achieved regardless of the selected mode.

As described above, according to the present invention, it is possible to obtain the driving sensations of both an MT vehicle and a normal EV, and when starting, an electric vehicle is able to perform acceleration peculiar to an EV. can be provided.

1 is a diagram schematically showing the configuration of a power system of an electric vehicle according to an embodiment of the present invention. 2 is a block diagram showing the configuration of a control system for the electric vehicle shown in FIG. 1. FIG. FIG. 2 is a block diagram showing functions of a control device for the electric vehicle shown in FIG. 1. FIG. 4 is a diagram showing an example of a motor torque command map included in the control device shown in FIG. 3. FIG. 4 is a block diagram showing an example of an MT vehicle model included in the control device shown in FIG. 3. FIG. 6 is a diagram showing an example of an engine model that constitutes the MT vehicle model shown in FIG. 5. FIG. 6 is a diagram showing an example of a clutch model that constitutes the MT vehicle model shown in FIG. 5. FIG. 6 is a diagram showing an example of an MT model that constitutes the MT vehicle model shown in FIG. 5. FIG. FIG. 3 is a diagram illustrating the torque characteristics of the electric motor realized in the MT driving mode in comparison with the torque characteristics of the electric motor realized in the EV driving mode. 4 is a flowchart showing a process executed by a driving mode determination unit of the control device shown in FIG. 3. FIG. FIG. 4 is a diagram showing an example of a motor torque selected according to vehicle speed and gear stage by a driving mode determination section of the control device shown in FIG. 3 when the MT mode is selected by the mode selection switch shown in FIG. 1; FIG. 2 is a block diagram showing the functions of the control device for the electric vehicle shown in FIG. 1 when a modified aspect is adopted. 4 is a flowchart showing a process executed by a driving mode determination unit of the control device shown in FIG. 3 when a modified aspect is adopted.

Embodiments of the present invention will be described below with reference to the drawings. However, in the embodiments shown below, when referring to the number, quantity, amount, range, etc. of each element, unless it is specifically specified or it is clearly specified to that number in principle, This invention is not limited to the number. Furthermore, the structures and the like described in the embodiments shown below are not necessarily essential to the present invention, unless specifically specified or clearly specified in principle. In each figure, the same or corresponding parts are denoted by the same reference numerals, and repeated explanations thereof will be simplified or omitted as appropriate.

1. Configuration of Electric Vehicle FIG. 1 is a diagram schematically showing the configuration of a power system of an electric vehicle 10 according to the present embodiment. As shown in FIG. 1, the electric vehicle 10 includes an electric motor 2 as a power source. The electric motor 2 is, for example, a brushless DC motor or a three-phase AC synchronous motor. The electric motor 2 is provided with a rotation speed sensor 40 for detecting its rotation speed. An output shaft 3 of the electric motor 2 is connected to one end of a propeller shaft 5 via a gear mechanism 4. The other end of the propeller shaft 5 is connected to a drive shaft 7 at the front of the vehicle via a differential gear 6.

The electric vehicle 10 includes driving wheels 8, which are front wheels, and driven wheels 12, which are rear wheels. Drive wheels 8 are provided at both ends of the drive shaft 7, respectively. Each wheel 8, 12 is provided with a wheel speed sensor 30. In FIG. 1, only the wheel speed sensor 30 of the right rear wheel is representatively depicted. The wheel speed sensor 30 is also used as a vehicle speed sensor for detecting the vehicle speed of the electric vehicle 10. The wheel speed sensor 30 is connected to a control device 50, which will be described later, via an in-vehicle network such as a CAN (Controller Area Network).

Electric vehicle 10 includes a battery 14 and an inverter 16. Battery 14 stores electrical energy for driving electric motor 2 . Inverter 16 converts DC power input from battery 14 into driving power for electric motor 2 . Power conversion by the inverter 16 is performed by PWM (Pulse Wave Modulation) control by the control device 50. Inverter 16 is connected to control device 50 via an in-vehicle network.

The electric vehicle 10 has an accelerator pedal (acceleration pedal) 22 for inputting an acceleration request and a brake for inputting a braking request as an operation request input device for the driver to input an operation request for the electric vehicle 10. It is equipped with a pedal 24. The accelerator pedal 22 is provided with an accelerator position sensor 32 for detecting the accelerator opening degree Pap [%], which is the operation amount of the accelerator pedal 22 . Further, the brake pedal 24 is provided with a brake position sensor 34 for detecting the amount of brake depression, which is the amount of operation of the brake pedal 24. An accelerator position sensor 32 and a brake position sensor 34 are connected to a control device 50 via an in-vehicle network.

The electric vehicle 10 further includes a pseudo shift lever (pseudo shift device) 26 and a pseudo clutch pedal 28 as operation input devices. A shift lever (shift device) and a clutch pedal are devices for operating a manual transmission (MT), but of course the electric vehicle 10 does not have an MT. The pseudo shift lever 26 and the pseudo clutch pedal 28 are merely dummies different from the original shift lever and clutch pedal.

The pseudo shift lever 26 has a structure that simulates a shift lever included in an MT vehicle. The arrangement and operational feel of the pseudo shift lever 26 are equivalent to those of an actual MT vehicle. The pseudo shift lever 26 is provided with positions corresponding to, for example, 1st, 2nd, 3rd, 4th, 5th, 6th, and neutral gear stages. The pseudo shift lever 26 is provided with a shift position sensor 36 that detects a shift position Sp indicating which position the pseudo shift lever 26 is located. Shift position sensor 36 is connected to control device 50 via an on-vehicle network.

The pseudo clutch pedal 28 has a structure that simulates a clutch pedal provided in an MT vehicle. The arrangement and operational feel of the pseudo clutch pedal 28 are equivalent to those of an actual MT vehicle. When the driver wants to change the gear setting using the pseudo shift lever 26, he depresses the pseudo clutch pedal 28, and when he finishes changing the gear setting, he stops depressing the pedal and returns the pseudo clutch pedal 28 to its original position. The pseudo clutch pedal 28 is provided with a clutch position sensor 38 for detecting the clutch pedal depression amount Pc [%] of the pseudo clutch pedal 28. Clutch position sensor 38 is connected to control device 50 via an on-vehicle network.

The electric vehicle 10 is equipped with a pseudo engine speed meter 44. The engine rotation speed meter is a device that displays the rotation speed of the internal combustion engine (engine) to the driver, but of course the electric vehicle 10 does not include an engine. The pseudo engine speed meter 44 is merely a dummy that is different from the original engine speed meter. The pseudo engine rotation speed meter 44 has a structure that simulates an engine rotation speed meter provided in a conventional vehicle. The pseudo engine speed meter 44 may be of a mechanical type or a liquid crystal display type. In the case of a liquid crystal display type, the rev limit may be set arbitrarily. The pseudo engine speed meter 44 is connected to the control device 50 via an on-vehicle network.

The electric vehicle 10 includes a mode selection switch 42. The mode selection switch 42 is a switch for selecting a driving mode of the electric vehicle 10. The driving modes of the electric vehicle 10 include an MT mode and an EV mode. The mode selection switch 42 is configured to be able to arbitrarily select either MT mode or EV mode. Although details will be described later, in the MT mode, the electric motor 2 is controlled in a control mode (first mode) for driving the electric vehicle 10 like a MT vehicle. In the EV mode, the electric motor 2 is controlled in a normal control mode (second mode) for general electric vehicles. The mode selection switch 42 is connected to the control device 50 via an in-vehicle network.

The electric vehicle 10 includes a control device 50. Control device 50 is typically an ECU (Electronic Control Unit) mounted on electric vehicle 10. The control device 50 may be a combination of multiple ECUs. Alternatively, the control device 50 may be an information processing device external to the electric vehicle 10. The control device 50 includes an interface 52, a memory 54, and a processor 56. An in-vehicle network is connected to the interface 52. The memory 54 includes a RAM (Random Access Memory) that temporarily records data, and a ROM (Read Only Memory) that stores a control program executable by the processor 56 and various data related to the control program. . The processor 56 reads control programs and data from the memory 54 and executes them, and generates control signals based on signals acquired from each sensor.

FIG. 2 is a block diagram showing the configuration of a control system for electric vehicle 10 according to the present embodiment. Signals are input to the control device 50 from at least the wheel speed sensor 30 , the accelerator position sensor 32 , the brake position sensor 34 , the shift position sensor 36 , the clutch position sensor 38 , the rotational speed sensor 40 , and the mode selection switch 42 . An in-vehicle network is used for communication between these sensors and the control device 50. Although not shown, various other sensors are mounted on the electric vehicle 10 and connected to the control device 50 via an on-vehicle network.

Furthermore, signals are output from the control device 50 to at least the inverter 16 and the pseudo engine speed meter 44. Control device 50 performs torque control of electric motor 2 via inverter 16 . An in-vehicle network is used for communication between these devices and the control device 50. Although not shown, various other actuators and indicators are mounted on the electric vehicle 10 and connected to the control device 50 via an on-vehicle network.

The control device 50 has a function as a driving mode determination section 500 and a function as a control signal calculation section 520. Specifically, the program stored in the memory 54 (see FIG. 1) is executed by the processor 56 (see FIG. 1), so that the processor 56 functions as at least the driving mode determination section 500 and the control signal calculation section 520. Function. The driving mode determination is a function of determining in which driving mode, EV mode or MT mode, the electric vehicle 10 is to be driven. Control signal calculation is a function of calculating control signals for actuators and devices. The control signal includes at least a signal for controlling the torque of the electric motor 2 via the inverter 16 and a signal for displaying information on the pseudo engine speed meter 44. Hereinafter, these functions that the control device 50 has will be explained.

2. Control device functions 2-1. Motor Torque Calculation Function FIG. 3 is a block diagram showing functions of the control device 50 according to the present embodiment, particularly functions related to calculation of a motor torque command value for the electric motor 2. As shown in FIG. Control device 50 calculates a motor torque command value using the functions shown in this block diagram, and generates a control signal for controlling the torque of electric motor 2 via inverter 16 based on the motor torque command value.

As shown in FIG. 3, the control signal calculation section 520 includes an MT vehicle model 530, a required motor torque calculation section 540, a motor torque command map 550, and a changeover switch 560. Signals from the wheel speed sensor 30 , the accelerator position sensor 32 , the shift position sensor 36 , the clutch position sensor 38 , and the rotational speed sensor 40 are input to the control signal calculation unit 520 . The control signal calculation unit 520 processes the signals from these sensors and calculates the motor torque to be outputted to the electric motor 2.

There are two ways to calculate the motor torque by the control signal calculation unit 520: calculation using the MT vehicle model 530 and requested motor torque calculation unit 540, and calculation using the motor torque command map 550. The former is used to calculate the motor torque when the electric vehicle 10 is driven in the MT mode. The latter is used to calculate the motor torque when the electric vehicle 10 is driven in EV mode. Which motor torque is used is determined by the changeover switch 560. The switching by the changeover switch 560 is performed based on the determination result by the driving mode determining section 500.

2-2. Calculation of motor torque in MT mode Drive wheel torque in an MT vehicle is determined by the operation of the gas pedal that controls fuel supply to the engine, the operation of the shift lever (shift device) that changes the MT gear, and the difference between the engine and MT. This is determined by the operation of the clutch pedal that operates the clutch. The MT vehicle model 530 is a model that calculates drive wheel torque obtained by operating the accelerator pedal 22, the pseudo clutch pedal 28, and the pseudo shift lever 26. Hereinafter, in the MT mode, the engine, clutch, and MT virtually realized by the MT vehicle model 530 will be referred to as a virtual engine, a virtual clutch, and a virtual MT.

A signal from the accelerator position sensor 32 is input to the MT vehicle model 530 as the operation amount of the gas pedal of the virtual engine. A signal from the shift position sensor 36 is input as the shift position of the shift lever of the virtual MT. Further, a signal from the clutch position sensor 38 is input as the operation amount of the clutch pedal of the virtual clutch. In addition, a signal from the wheel speed sensor 30 is also input to the MT vehicle model 530 as a signal indicating the load state of the vehicle. The MT vehicle model 530 is a model that simulates the torque characteristics of drive wheel torque in an MT vehicle. The MT vehicle model 530 is created so that the driver's operations of the accelerator pedal 22, pseudo shift lever 26, and pseudo clutch pedal 28 are reflected in the value of the drive wheel torque. Details of the MT vehicle model 530 will be described later.

The required motor torque calculation unit 540 converts the drive torque calculated by the MT vehicle model 530 into a required motor torque. The required motor torque is the motor torque required to realize the drive torque calculated by the MT vehicle model 530. The reduction ratio from the output shaft 3 of the electric motor 2 to the drive wheels 8 is used to convert the drive torque into the required motor torque.

2-3. Calculation of Motor Torque in EV Mode FIG. 4 is a diagram showing an example of a motor torque command map 550 used to calculate motor torque in EV mode. The motor torque command map 550 is a map that determines the motor torque using the accelerator opening, Pap, and the rotational speed of the electric motor 2 as parameters. A signal from the accelerator position sensor 32 and a signal from the rotational speed sensor 40 are input to each parameter of the motor torque command map 550. Motor torque command map 550 outputs motor torque corresponding to these signals.

2-4. Switching Motor Torque The motor torque calculated using the motor torque command map 550 is expressed as Tev, and the motor torque calculated using the MT vehicle model 530 and the required motor torque calculation unit 540 is expressed as Tmt. The motor torque selected by the changeover switch 560 from the two motor torques Tev and Tmt is given to the electric motor 2 as a motor torque command value.

In the EV mode, even if the driver operates the pseudo shift lever 26 or the pseudo clutch pedal 28, the operation is not reflected in the operation of the electric vehicle 10. That is, in the EV mode, the operation of the pseudo shift lever 26 and the operation of the pseudo clutch pedal 28 are disabled. However, even while the motor torque Tev is being output as the motor torque command value, calculation of the motor torque Tmt using the MT vehicle model 530 continues. Conversely, calculation of the motor torque Tev continues even while the motor torque Tmt is being output as the motor torque command value. That is, both the motor torque Tev and the motor torque Tmt are continuously input to the changeover switch 560.

By switching the input using the changeover switch 560, the motor torque command value is switched from motor torque Tev to motor torque Tmt, or from motor torque Tmt to motor torque Tev. At this time, if there is a difference between the two motor torques, a torque step will occur due to switching. Therefore, for a while after switching, gradual change processing is performed on the motor torque command value so that a sudden change in torque does not occur. For example, when switching from EV mode to MT mode, the motor torque command value is not immediately switched from motor torque Tev to motor torque Tmt, but is gradually changed toward motor torque Tmt at a predetermined rate of change. Similar processing is performed when switching from MT mode to EV mode.

The changeover switch 560 is operated by a signal from a driving mode determining section 500, which will be described later. In addition to the signal from the mode selection switch 42, the driving mode determination section 500 receives signals from the wheel speed sensor 30 and the shift position sensor 36. Information about the vehicle speed of the host vehicle is acquired by the wheel speed sensor 30 . The shift position sensor 36 acquires gear position information in the MT vehicle model. The driving mode determining unit 500 operates the changeover switch 560, taking into account not only the selection made by the mode selection switch 42 but also the vehicle speed of the host vehicle and the gear position in the MT vehicle model. Details of the operation of the changeover switch 560 by the driving mode determining section 500 will be described later.

2-5. MT vehicle model 2-5-1. Overview Next, the MT vehicle model 530 will be explained. FIG. 5 is a block diagram showing an example of the MT vehicle model 530. The MT vehicle model 530 includes an engine model 531, a clutch model 532, an MT model 533, and an axle/drive wheel model 534. The engine model 531 models a virtual engine. In the clutch model 532, a virtual clutch is modeled. The MT model 533 is a virtual MT modeled. The axle/drive wheel model 534 models a virtual torque transmission system from the axle to the drive wheels. Each model may be represented by a calculation formula or a map.

Calculation results are input and output between each model. Furthermore, the accelerator opening degree Pap detected by the accelerator position sensor 32 is input to the engine model 531 . A clutch pedal depression amount Pc detected by the clutch position sensor 38 is input to the clutch model 532. The shift position Sp detected by the shift position sensor is input to the MT model 533. Furthermore, in the MT vehicle model 530, the vehicle speed Vw (or wheel speed) detected by the wheel speed sensor 30 is used in a plurality of models. In the MT vehicle model 530, the driving wheel torque Tw and the virtual engine rotation speed Ne are calculated based on these input signals.

2-5-2. Engine Model The engine model 531 calculates virtual engine rotation speed Ne and virtual engine output torque Teout. The engine model 531 includes a model that calculates the virtual engine rotational speed Ne and a model that calculates the virtual engine output torque Teout. For example, a model expressed by the following equation (1) is used to calculate the virtual engine rotational speed Ne. In the following equation (1), a virtual engine rotation speed Ne is calculated from the rotation speed Nw of the driving wheels 8, the overall reduction ratio R, and the slip ratio slip of the clutch mechanism.

In equation (1), the rotational speed Nw of the drive wheel 8 is calculated from the wheel speed detected by the wheel speed sensor 30. The overall reduction ratio R is calculated from a gear ratio (speed ratio) r calculated by an MT model 533, which will be described later, and a reduction ratio defined by an axle/drive wheel model 534. The slip rate slip is calculated by a clutch model 532, which will be described later. The virtual engine rotation speed Ne is displayed on the pseudo engine rotation speed meter 44 when the MT mode is selected.

Note that while the MT vehicle is idling, idle speed control control (ISC control) is performed to maintain the engine rotation speed at a constant rotation speed. Therefore, when the vehicle speed is 0 and the accelerator opening Pap is 0%, the engine model 531 calculates the virtual engine rotation speed Ne as a predetermined idling rotation speed (for example, 1000 rpm).

Engine model 531 calculates virtual engine output torque Teout from virtual engine rotational speed Ne and accelerator opening Pap. For example, a two-dimensional map as shown in FIG. 7 is used to calculate the virtual engine output torque Teout. In this two-dimensional map, a virtual engine output torque Teout for a virtual engine rotational speed Ne is given for each accelerator opening Pap. The torque characteristics shown in FIG. 6 can be set to characteristics assuming a gasoline engine, or can be set to characteristics assuming a diesel engine. Furthermore, the characteristics can be set assuming a naturally aspirated engine, or the characteristics can be set assuming a supercharged engine. A switch for switching the virtual engine in MT mode may be provided so that the driver can switch to his or her preferred setting. The virtual engine output torque Teout calculated by the engine model 531 is output to the clutch model 532.

2-5-3. Clutch Model Clutch model 532 calculates torque transfer gain k. The torque transmission gain k is a gain for calculating the degree of torque transmission of the virtual clutch according to the amount of depression of the pseudo clutch pedal 28. The clutch model 532 has a map as shown in FIG. 7, for example. In this map, a torque transmission gain k is given to the clutch pedal depression amount Pc. In FIG. 7, the torque transmission gain k becomes 1 when the clutch pedal depression amount Pc ranges from Pc0 to Pc1, monotonically decreases with a constant slope to 0 when the clutch pedal depression amount Pc ranges from Pc1 to Pc2, and the torque transmission gain k becomes 1 when the clutch pedal depression amount Pc ranges from Pc1 to Pc2. Pc is given so that it becomes 0 in the range from Pc2 to Pc3. Here, Pc0 corresponds to the clutch pedal depression amount Pc of 0%, Pc1 corresponds to the free play limit when the clutch pedal is depressed, Pc3 corresponds to the clutch pedal depression amount Pc of 100%, and Pc2 corresponds to the clutch pedal depression amount Pc from Pc3. It corresponds to the play limit when returning.

The map shown in FIG. 7 is an example, and the change curve of the torque transmission gain k with respect to the increase in the clutch pedal depression amount Pc is not limited as long as it is a broad monotonous decrease toward 0. For example, the change in torque transmission gain k from Pc1 to Pc2 may be a monotonically decreasing curve that is convex upward, or may be a monotonically decreasing curve that is convex downward.

Clutch model 532 calculates clutch output torque Tcout using torque transmission gain k. Clutch output torque Tcout is torque output from the virtual clutch. The clutch model 532 calculates the clutch output torque Tcout from the virtual engine output torque Teout and the torque transmission gain k using, for example, the following equation (2). The clutch output torque Tcout calculated by the clutch model 532 is output to the MT model 533.

2-5-4. MT Model The MT model 533 calculates the gear ratio (speed ratio) r. The gear ratio r is a gear ratio determined by the shift position Sp of the pseudo shift lever 26 in the virtual MT. The shift position Sp of the pseudo shift lever 26 and the gear stage of the virtual MT have a one-to-one relationship. The MT model 533 has a map as shown in FIG. 8, for example. In this map, a gear ratio r is given for each gear stage. As shown in FIG. 8, the gear ratio r becomes smaller as the gear stage becomes larger.

The MT model 533 calculates the transmission output torque Tgout using the gear ratio r. The transmission output torque Tgout is the torque output from the virtual transmission. The MT model 533 calculates the transmission output torque Tgout from the clutch output torque Tcout and the gear ratio r, for example, using the following equation (3). The transmission output torque Tgout calculated by the MT model 533 is output to the axle/drive wheel model 534.

2-5-5. Axle/Drive Wheel Model The axle/drive wheel model 534 calculates the drive wheel torque Tw using a predetermined reduction ratio rr. The reduction ratio rr is a fixed value determined by the mechanical structure from the virtual MT to the drive wheels 8. The axle/driving wheel model 534 calculates the driving wheel torque Tw from the transmission output torque Tgout and the reduction ratio rr, for example, using the following equation (4). The drive wheel torque Tw calculated by the axle/drive wheel model 534 is output to the required motor torque calculation unit 540.

2-6. Torque Characteristics of Electric Motor Realized in MT Mode The required motor torque calculation unit 540 converts the drive wheel torque Tw calculated by the MT vehicle model 530 into motor torque. FIG. 9 is a diagram showing the torque characteristics of the electric motor 2 realized in the MT driving mode in comparison with the torque characteristics of the electric motor 2 realized in the EV driving mode. In the case of the MT mode, as shown in FIG. 9, torque characteristics (solid line in the figure) that simulate the torque characteristics of an MT vehicle can be realized according to the gear stage set by the pseudo shift lever 26.

2-7. Driving Mode Determination Next, the operation of the changeover switch 560 by the driving mode determining section 500 of the control device 50 will be described. The operation of the changeover switch 560 by the driving mode determination unit 500 is performed in consideration of the mode selected by the mode selection switch 42, the vehicle speed detected by the wheel speed sensor 30, and the shift position Sp detected by the shift position sensor 36. It will be done. FIG. 10 is a flowchart showing the processing executed by the driving mode determination section 500. The process shown in FIG. 10 is repeatedly executed at a predetermined control cycle of the control device 50.

In step S510, the control device 50 determines whether the selection by the mode selection switch 42 is the MT mode or the EV mode. If the mode is MT mode (step S510; Yes), the process advances to step S511. If it is the EV mode (step S510; No), the process proceeds to step S521, and the selector switch 560 is operated to set the motor torque Tev.

In step S511, the control device 50 acquires information on vehicle speed and gear stage. The vehicle speed is a value detected by the wheel speed sensor 30. The gear stage is a gear stage of the virtual MT corresponding to the shift position Sp detected by the shift position sensor 36. Further, the acquired information is stored in the memory 54 at least until the next control cycle, and the control device 50 can refer to the information acquired in the previous control cycle. After the process in step S511, the process advances to step S512.

In step S512, control device 50 determines whether electric vehicle 10 is decelerating. The determination as to whether the electric vehicle 10 is decelerating is performed, for example, as follows. The vehicle speed acquired in step S511 of the previous control cycle is compared with the vehicle speed acquired in step S511 of the current control cycle, and when the value becomes smaller, it is determined that the vehicle is decelerating. Alternatively, in order to suppress misjudgments due to perturbations in the acquired vehicle speed, filtering processing is performed on the vehicle speed data acquired over a certain period of time, and it is determined that the vehicle is decelerating if the slope of the vehicle speed becomes negative within a certain period of time. You may do so.

If the electric vehicle 10 is decelerating (step S512; Yes), the process advances to step S513. If the electric vehicle 10 is not decelerating (step S512; No), the process proceeds to step S520.

In step S513, the control device 50 sets the motor torque selected in the current control cycle to the motor torque selected in the previous control cycle. That is, if motor torque Tmt in MT mode was selected in the previous control cycle, motor torque Tmt is also selected in the current control cycle. Conversely, if motor torque Tev in EV mode was selected in the previous control cycle, motor torque Tev is also selected in the current control cycle.

That is, if it is determined in step S512 that the electric vehicle 10 is decelerating, the motor torque switching process is not performed.

In step S520, the control device 50 determines whether the vehicle speed is less than a predetermined value or the gear position is less than a predetermined value. The predetermined values for the vehicle speed and gear stage are set, for example, to values such that the torque of the electric motor 2 realized in the MT drive mode is equivalent to the torque of the electric motor 2 realized in the EV drive mode. For example, in FIG. 9, the setting is made based on the intersection of the torque characteristic of the electric motor 2 realized in the MT driving mode of the 1st gear stage (solid line in the figure) and the torque characteristic in the EV mode (dotted line in the figure). In this case, the predetermined value for the gear stage is 2nd, and the predetermined value for the vehicle speed is the vehicle speed calculated from the rotational speed of the electric motor 2 at the intersection and the gear ratio up to the drive wheels.

If either the vehicle speed is less than the predetermined value or the gear position is less than the predetermined value (step S520; Yes), the process proceeds to step S521, and the changeover switch is set to the motor torque Tev. Operate 560. If the vehicle speed is greater than or equal to the predetermined value and the gear position is greater than or equal to the predetermined value (step S520; No), the process proceeds to step S530.

In step S530, the control device 50 determines whether the gear stage has been changed between the previous control cycle and the current control cycle. The determination as to whether or not the gear stage has been changed is performed, for example, as follows. The gear stage acquired in the previous control cycle stored in the memory 54 is compared with the gear stage acquired in the current control cycle, and the determination is made based on whether or not there is a change in the value.

If the gear position has been changed (step S530; Yes), the process proceeds to step S531, and the selector switch 560 is operated so that the motor torque becomes Tmt. If the gear position has not been changed (step S530; No), the process proceeds to step S521, and the changeover switch 560 is operated to set the motor torque Tev.

FIG. 11 is a diagram showing an example of the motor torque selected by the driving mode determination unit 500 when the MT mode is selected by the mode selection switch 42 (step S510; Yes). The predetermined value of the vehicle speed is shown by a thin line in the vehicle speed graph of FIG. The predetermined value of the gear stage is 2nd. dt represents the control period of the control device 50, and the process by the driving mode determination unit 500 shown in FIG. 10 is executed at each time point of time t1, t2, t3, t4, t5, and t6.

Further, at time t0, which is the starting point in each graph, the electric vehicle 10 is stopped. In other words, the graph shown in FIG. 11 shows the behavior of the electric vehicle 10 from the time of starting. At time t0, motor torque Tev is selected.

The electric vehicle 10 is accelerating from time t1 to t4 in FIG. 11 (step S512; Yes). On the other hand, the electric vehicle 10 is decelerating from time t4 to time t6 (step S512; No).

At time t1 in FIG. 11, the vehicle speed is less than the predetermined value and the gear position is also less than the predetermined value (step S520; Yes), so the motor torque Tev is selected.

At time t2 in FIG. 11, the gear position is equal to or higher than the predetermined value, but the vehicle speed is less than the predetermined value (step S520; Yes), so the motor torque Tev is selected.

At time t3 in FIG. 11, the vehicle speed is at least a predetermined value and the gear position is at least a predetermined value (step S520; No). Further, since the gear stage (2nd) at time t2 of the previous control cycle has been changed (step S530; Yes), the motor torque is switched to Tmt.

At time t6 in FIG. 11, the vehicle speed is less than the predetermined value and the gear stage is also less than the predetermined value, but since the electric vehicle 10 is decelerating (step S512; Yes), the motor torque is not switched, and the motor torque Tmt is selected.

In the electric vehicle 10 according to the present embodiment, even if the MT mode is selected by the mode selection switch 42, the motor torque Tev may be selected. For this reason, the control device 50 may be configured to notify the driver by display or voice as to which of the motor torque Tmt and the motor torque Tev is selected.

3. Effects As described above, according to the electric vehicle 10 according to the present embodiment, the driver can drive the electric vehicle like an MT vehicle by selecting the MT mode using the mode selection switch 42. Furthermore, by selecting the EV mode using the mode selection switch 42, the driver can drive the electric vehicle with its original performance. This makes it possible to obtain the driving sensations of both an MT vehicle and a normal EV.

Furthermore, even if the MT mode is selected by the mode selection switch 42, if either the gear stage is less than a predetermined value or the vehicle speed is less than a predetermined value, The control device 50 controls the torque of the electric motor 2 so that the motor torque Tev is achieved. Thereby, at the time of starting, acceleration peculiar to an EV can be performed regardless of the mode selected by the mode selection switch 42.

4. Modifications The electric vehicle 10 according to the present embodiment may adopt a modified form as described below.

The control device 50 may be configured so that the driving mode determining unit 500 selects the motor torque by also considering the motor torque Tmt output by the required motor torque calculating unit 540.

FIG. 12 is a block diagram showing the functions of the control device 50 of the electric vehicle 10 according to the modification. In this control device 50, the driving mode determining section 500 receives as input the motor torque Tmt output from the required motor torque calculating section 540.

FIG. 13 is a flowchart showing a process executed by the driving mode determination unit 500 of the electric vehicle 10 according to the modification. The process shown in FIG. 13 is the same as the process shown in FIG. 10 except for step S540. Therefore, the description of processes other than step S540 will be omitted below.

In step S540, control device 50 determines whether motor torque Tmt is larger than a predetermined value. If the motor torque Tmt is larger than the predetermined value (step S540; Yes), the process proceeds to step S531, and the changeover switch 560 is operated so that the motor torque Tmt is achieved. If the motor torque Tmt is smaller than the predetermined value (step S540; No), the process proceeds to step S521, and the changeover switch 560 is operated so that the motor torque Tev is achieved.

By adopting this modified mode, the motor torque Tev for the EV mode is selected only when the operation of the accelerator pedal 22 is appropriate and it is considered that the driver is requesting a start in the EV mode. The control device 50 can be configured to At this time, if the accelerator pedal 22 is operated sufficiently, the vehicle can start with the motor torque Tmt in the MT mode even if the vehicle speed is less than a predetermined value or the gear position is less than a predetermined value.

Therefore, the predetermined value in step S540 is determined based on the operating range of the accelerator pedal 22 in which the driver is considered to be requesting a start in EV mode. For example, it is determined by vehicle compatibility of the electric vehicle 10, etc.

2 Electric motor 10 Electric vehicle 14 Battery 16 Inverter 22 Accelerator pedal 26 Pseudo shift lever 28 Pseudo clutch pedal 30 Wheel speed sensor 32 Accelerator position sensor 34 Brake position sensor 36 Shift position sensor 38 Clutch position sensor 40 Rotation speed sensor 42 Mode selection switch 50 Control device 500 Travel mode determination section 520 Control signal calculation section

Claims (1)

An electric vehicle that uses an electric motor as a driving power device,
an accelerator pedal,
pseudo clutch pedal,
A pseudo shift device,
a mode selection switch that selects a control mode of the electric motor between a first mode and a second mode;
a control device that controls a motor torque output by the electric motor according to the control mode selected by the mode selection switch;
The control device includes:
memory and
comprising a processor;
The memory is
An MT vehicle model that simulates the torque characteristics of drive wheel torque in an MT vehicle that has an internal combustion engine that controls torque by operating a gas pedal and a manual transmission that changes gears by operating a clutch pedal and a shift device;
storing a motor torque command map that defines a relationship between the operation amount of the acceleration pedal and the motor torque with respect to the rotational speed of the electric motor;
The processor includes:
When controlling the electric motor in the first mode,
a process of accepting the operation amount of the acceleration pedal as an input of the operation amount of the gas pedal for the MT vehicle model;
a process of accepting the operation amount of the pseudo clutch pedal as an input of the operation amount of the clutch pedal for the MT vehicle model;
a process of accepting a shift position of the pseudo shift device as an input of the shift device for the MT vehicle model;
a process of calculating the drive wheel torque determined by the operation amount of the acceleration pedal, the operation amount of the pseudo clutch pedal, and the shift position of the pseudo shift device using the MT vehicle model;
When controlling the electric motor in the second mode by performing a process of calculating the motor torque for applying the drive wheel torque to the drive wheels of the host vehicle,
processing for disabling the operation of the pseudo clutch pedal and the operation of the pseudo shift device;
calculating the motor torque using the motor torque command map based on the operation amount of the acceleration pedal and the rotational speed of the electric motor;
When the first mode is selected by the mode selection switch, whether the gear stage of the MT vehicle model determined by the shift position is less than a predetermined value or the vehicle speed of the host vehicle is less than a predetermined value. If either one is true,
An electric vehicle characterized in that the electric motor is controlled so that the motor torque is in the second mode.

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