Electric vehicles

Abstract

To eliminate trouble due to not-fixation of a control mode when a vehicle is activated, while enjoying both driving like a MT vehicle and driving of a normal electric vehicle by switching of the control mode.SOLUTION: An electric automobile includes a mode selection device and a control device. The mode selection device selects any one of an EV mode and an MT mode according to mode selection operation of a driver. The control device changes output of the electric motor according to operation of the accelerator pedal without depending on the operation position of the shifter when the electric motor is controlled in the EV mode, and changes output characteristics of the electric motor for operation of the accelerator pedal according to the operation position of the shifter when the electric motor is controlled in the MT mode. The mode selection device automatically selects the EV mode, when the electric automobile is activated, and switches the control mode from the EV mode to the MT mode in response to the selection operation of the MT mode by the driver.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to an electric vehicle that uses an electric motor as a driving power device.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2021-118569 discloses a technique for simulating torque characteristics of a vehicle (hereinafter referred to as an MT vehicle) equipped with a manual transmission and an internal combustion engine by controlling the motor torque of an electric vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By making it possible to switch between a control mode that provides torque characteristics like those of an MT vehicle and a control mode that has the torque characteristics of a normal electric vehicle, a driver can selectively enjoy both driving like an MT vehicle and driving as a normal electric vehicle. However, on the other hand, if the control mode when starting the vehicle is different each time, the driver will feel annoyed because they have to cope with the differences in vehicle operation due to the differences in the control modes.

[0005] The present disclosure has been made in view of the above problems. One object of the present disclosure is to enable a driver to selectively enjoy both driving like an MT vehicle and driving as a normal electric vehicle by switching the control mode in an electric vehicle that uses an electric motor as a driving power device, while eliminating the annoyance caused by the indeterminate control mode when starting the vehicle.

Means for Solving the Problems

[0006] This disclosure provides an electric vehicle for achieving the above objective. The electric vehicle of this disclosure comprises an accelerator pedal, a shifter, a mode selection device, and a control device. The mode selection device is a device that selects either a first mode or a second mode as the control mode of the electric motor according to the driver's mode selection operation. The control device is a device that controls the electric motor according to the control mode selected by the mode selection device. When the electric motor is controlled in the first mode, the control device is configured to change the output of the electric motor in response to the operation of the accelerator pedal, regardless of the shifter's operating position, and when the electric motor is controlled in the second mode, it is configured to change the output characteristics of the electric motor in response to the operation of the accelerator pedal according to the shifter's operating position. The mode selection device is configured to automatically select a specific control mode from the first mode and the second mode when the electric vehicle is started up. [Effects of the Invention]

[0007] According to the electric vehicle of this disclosure, the driver can selectively enjoy both driving as a normal electric vehicle by selecting the first mode and driving like a manual transmission vehicle by selecting the second mode, without causing the driver any inconvenience caused by the control mode not being determined when the vehicle starts up. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows the configuration of an electric vehicle according to an embodiment of the present disclosure. [Figure 2] Figure 1 is a block diagram showing the configuration of the control system for an electric vehicle. [Figure 3] Figure 1 is a block diagram showing the functions of the control device for an electric vehicle. [Figure 4] This flowchart shows the procedure for mode switching processing by the mode selection device. [Figure 5] This block diagram shows an example of a manual transmission vehicle model equipped with the control device shown in Figure 3. [Figure 6]Figure 5 shows an example of the engine model, clutch model, and transmission model that make up the MT vehicle model. [Modes for carrying out the invention]

[0009] 1. Electric Vehicle Configuration Figure 1 is a schematic diagram showing the configuration of the powertrain of the electric vehicle 10 according to this embodiment. As shown in Figure 1, the electric vehicle 10 is equipped with 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 rotational speed sensor 40 for detecting its rotational speed. The output shaft 3 of the electric motor 2 is connected to one end of the propeller shaft 5 via a gear mechanism 4. The other end of the propeller shaft 5 is connected to the drive shaft 7 at the front of the vehicle via a differential gear 6.

[0010] The electric vehicle 10 is equipped with drive wheels 8, which are the front wheels, and driven wheels 12, which are the rear wheels. The drive wheels 8 are located at both ends of the drive shaft 7. Wheel speed sensors 30 are provided on each wheel 8 and 12. In Figure 1, only the wheel speed sensor 30 of the right rear wheel is shown as a representative example. The wheel speed sensors 30 are also used as vehicle speed sensors to detect the vehicle speed of the electric vehicle 10. The wheel speed sensors 30 are connected to a control device 50, which will be described later, via an in-vehicle network such as a Controller Area Network (CAN).

[0011] The electric vehicle 10 is equipped with a battery 14 and an inverter 16. The battery 14 stores electrical energy to drive the electric motor 2. In other words, the electric vehicle 10 is a battery electric vehicle (BEV) that runs on the electrical energy stored in the battery 14. The inverter 16 converts the DC power input from the battery 14 into driving power for the electric motor 2. The power conversion by the inverter 16 is performed by PWM control by the control device 50. The inverter 16 is connected to the control device 50 by an in-vehicle network.

[0012] The electric vehicle 10 is equipped with an accelerator pedal 22 for inputting acceleration requests and a brake pedal 24 for inputting braking requests, which serve as an operation request input device for the driver to input operation requests to the electric vehicle 10. The accelerator pedal 22 is equipped with an accelerator position sensor 32 for detecting the accelerator opening, which is the amount the accelerator pedal 22 is operated on. The brake pedal 24 is equipped with a brake position sensor 34 for detecting the amount the brake pedal 24 is operated on, which is the amount the brake pedal 24 is pressed down on. The accelerator position sensor 32 and the brake position sensor 34 are connected to the control device 50 by an in-vehicle network.

[0013] The electric vehicle 10 is further equipped with a simulated paddle shifter 26 as an input device. A paddle shifter, or paddle-type sequential shifter, is a device used to operate a sequential manual transmission (SMT), but naturally, the electric vehicle 10 does not have an SMT. The simulated paddle shifter 26 is merely a dummy and is different from a real paddle shifter. Generally, MT vehicles equipped with paddle shifters are clutch-less MT vehicles that do not have a clutch pedal. Therefore, although the electric vehicle 10 is equipped with a simulated paddle shifter 26, it does not have a simulated clutch pedal that resembles a clutch pedal.

[0014] The simulated paddle shifter 26 has a structure similar to the paddle shifters found in clutchless manual transmission vehicles. The simulated paddle shifter 26 is mounted on the steering wheel. The simulated paddle shifter 26 is equipped with an upshift switch 26u and a downshift switch 26d. The upshift switch 26u is located on the right side of the steering wheel, and the downshift switch 26d is located on the left side of the steering wheel. The upshift switch 26u and the downshift switch 26d can be operated independently. The upshift switch 26u emits a signal when pulled towards the driver, and the downshift switch 26d also emits a signal when pulled towards the driver. Hereinafter, the operation of pulling the upshift switch 26u towards the driver will be referred to as an upshift operation, and the signal emitted by the upshift switch 26u as a result of the upshift operation will be referred to as an upshift signal. Similarly, the operation of pulling the downshift switch 26d towards the driver will be referred to as a downshift operation, and the signal emitted by the downshift switch 26d as a result of the downshift operation will be referred to as a downshift signal. The upshift switch 26u and the downshift switch 26d are connected to the control unit 50 via the in-vehicle network.

[0015] The electric vehicle 10 is equipped with a mode selection switch 42. The mode selection switch 42 is a switch for selecting the control mode of the electric motor 2. There are two control modes for the electric motor 2: MT mode and EV mode. The mode selection switch 42 is configured to allow arbitrary selection of either MT mode or EV mode. As will be described in detail later, in EV mode, the electric motor 2 is controlled in the normal control mode (first mode) for a typical electric vehicle. In MT mode, the electric motor 2 is controlled in the control mode (second mode) for driving the electric vehicle 10 like a manual transmission vehicle. The mode selection switch 42 is connected to the control device 50 by an in-vehicle network.

[0016] The electric vehicle 10 includes a start switch 46. When the start switch 46 is turned on, a start signal is input from the start switch 46 to the control device 50. When the start switch 46 is turned off, a stop signal is input from the start switch 46 to the control device 50. When a start signal is input to the control device 50, the system of the electric vehicle 10 starts, and the electric vehicle 10 becomes capable of running. Then, when a stop signal is input to the control device 50, the system of the electric vehicle 10 stops, and the electric vehicle 10 becomes unable to run.

[0017] The control device 50 is typically an electronic control unit (ECU) mounted on the electric vehicle 10. The control device 50 may be a combination of a plurality of ECUs. 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 for temporarily recording data and a ROM for storing programs executable by the processor 56 and various data related to the programs. The program is composed of a plurality of instructions. The processor 56 reads the program and data from the memory 54 and executes them, and generates a control signal based on the signals acquired from each sensor.

[0018] FIG. 2 is a block diagram showing the configuration of the control system of the electric vehicle 10 according to the present embodiment. The control device 50 receives the input of signals from at least the wheel speed sensor 30, the accelerator position sensor 32, the brake position sensor 34, the upshift switch 26u, the downshift switch 26d, the rotational speed sensor 40, the drive mode selection switch 42, and the start switch 46. Also, the control device 50 outputs a signal to at least the inverter 16. Although not shown, various other sensors, actuators, and displays are mounted on the electric vehicle 10.

[0019] The control device 50 has a function as a control signal calculation unit 520. Specifically, when a program stored in the memory 54 is executed by the processor 56, the processor 56 functions at least as the control signal calculation unit 520. Control signal calculation is a function of calculating control signals for actuators and devices. The control signals include at least signals for PWM control of the inverter 16. Hereinafter, the functions of the control device 50 will be described.

[0020] 2. Functions of the control device 2-1. Motor torque calculation function 2-1-1. Functions of the control signal calculation unit FIG. 3 is a block diagram showing the functions of the control device 50 according to the present embodiment, particularly the functions related to the calculation of the motor torque command value for the electric motor 2. The control device 50 calculates the motor torque command value according to the functions shown in this block diagram, and generates a control signal for PWM control of the inverter 16 based on the motor torque command value.

[0021] As shown in FIG. 3, the control signal calculation unit 520 includes an MT vehicle model 530, a required motor torque calculation unit 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 upshift switch 26u, the downshift switch 26d, the rotational speed sensor 40, and the mode selection switch 42 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 output to the electric motor 2.

[0022] The motor torque calculation by the control signal calculation unit 520 can be performed in two ways: using the MT vehicle model 530 and the requested motor torque calculation unit 540, and using the motor torque command map 550. The former is used to calculate the motor torque when the electric vehicle 10 is driven in MT mode. The latter is used to calculate the motor torque when the electric vehicle 10 is driven in EV mode. Which motor torque to use is determined by the changeover switch 560. The changeover switch 560 is operated by a signal input from the mode selection switch 42. The changeover switch 560 and the mode selection switch 42 constitute a mode selection device.

[0023] 2-1-2. Calculation of motor torque in MT mode The MT vehicle model 530 is a model that calculates the drive wheel torque that should be obtained by operating the accelerator pedal 22 and the simulated paddle shifter 26, assuming that the electric vehicle 10 is a clutchless MT vehicle. A clutchless MT vehicle is an MT vehicle that has an engine, an SMT, and a clutch connecting the engine and the SMT, but does not have a clutch pedal because the clutch is operated automatically. The drive wheel torque in a clutchless MT vehicle is determined by operating the gas pedal, which controls the fuel supply to the engine, and operating the paddle shifter, which switches the gear position of the SMT. The engine may be a spark-ignition engine or a diesel engine. Hereinafter, the engine, clutch, and SMT that are virtually realized by the MT vehicle model 530 will be referred to as the virtual engine, virtual clutch, and virtual SMT, respectively.

[0024] In the MT vehicle model 530, the accelerator opening Pap detected by the accelerator position sensor 32 is input as the amount of operation of the gas pedal of the virtual engine. In addition, the MT vehicle model 530 receives the upshift signal Su transmitted from the upshift switch 26u and the downshift signal Sd transmitted from the downshift switch 26d as inputs for operation of the paddle shifter that determines the gear position of the virtual SMT. Furthermore, the MT vehicle model 530 also receives the vehicle speed Vw (or wheel speed) detected by the wheel speed sensor 30 as a signal indicating the load state of the vehicle.

[0025] The requested motor torque calculation unit 540 converts the drive wheel torque Tw calculated in the MT vehicle model 530 into a requested motor torque Tm. The requested motor torque Tm is the motor torque required to achieve the drive wheel torque Tw calculated in 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 wheel torque Tw into a requested motor torque Tm.

[0026] 2-1-3. Calculation of motor torque in EV mode In EV mode, even if the driver operates the simulated paddle shifter 26, that operation is not reflected in the operation of the electric vehicle 10. In other words, in EV mode, the operation of the simulated paddle shifter 26 is disabled. The motor torque command map 550, which is used to calculate the motor torque in EV mode, is a map that determines the motor torque using the accelerator opening and the rotational speed of the electric motor 2 as parameters. The signals from the accelerator position sensor 32 and the rotational speed sensor 40 are input to each parameter of the motor torque command map 550. The motor torque corresponding to these signals is output from the motor torque command map 550.

[0027] 2-1-4. Switching Motor Torque The motor torque calculated using the motor torque command map 550 is denoted as Tev, and the motor torque calculated using the MT vehicle model 530 and the requested motor torque calculation unit 540 is denoted as Tmt. Of the two motor torques, Tev and Tmt, the motor torque selected by the changeover switch 560 is given to the electric motor 2 as a motor torque command value. However, while the motor torque Tev is output as a motor torque command value, the calculation of the motor torque Tmt using the MT vehicle model 530 continues. Conversely, while the motor torque Tmt is output as a motor torque command value, the calculation of the motor torque Tev continues. In other words, both the motor torque Tev and the motor torque Tmt are continuously input to the changeover switch 560.

[0028] The changeover switch 560 operates according to the control mode selected by the mode selection switch 42. When EV mode is selected by the mode selection switch 42, the changeover switch 560 connects to the motor torque command map 550 and outputs the motor torque Tev input from the motor torque command map 550 as the motor torque command value. When MT mode is selected by the mode selection switch 42, the changeover switch 560 switches its connection destination to the requested motor torque calculation unit 540. The changeover switch 560 then outputs the motor torque Tmt input from the requested motor torque calculation unit 540 as the motor torque command value. This input switching is performed in conjunction with the selection of the control mode by the mode selection switch 42.

[0029] However, when the electric vehicle 10 is started, the changeover switch 560 automatically connects to a pre-set startup connection destination, regardless of which control mode was selected during the previous trip. The startup connection destination can be arbitrarily set by the driver using a hard switch or a soft switch. In the initial setting, the startup connection destination of the changeover switch 560 is set to the motor torque command map 550. In other words, the initial setting is such that when the driver turns on the start switch 46, it will always start in EV mode. In EV mode, any driver, even someone who is not comfortable driving a manual transmission vehicle, can easily start driving. If the driver wishes to start in manual transmission mode, they can change the setting to set the startup connection destination of the changeover switch 560 to the requested motor torque calculation unit 540.

[0030] Figure 4 is a flowchart showing the procedure for mode switching by a mode selection device consisting of a mode selection switch 42 and a changeover switch 560. Here, the control mode at startup is assumed to be the initial setting, EV mode.

[0031] In step S01, it is determined whether the start switch 46 is turned on. The system remains stopped until the start switch 46 is turned on. If the start switch 46 is turned on, the procedure proceeds to step S02.

[0032] In step S02, regardless of whether the previous trip ended in EV mode or MT mode, the changeover switch 560 is automatically connected to the motor torque command map 550. In other words, the EV mode is automatically selected when the start switch 46 is turned on, and the electric vehicle 10 is always started in EV mode. Next, the procedure proceeds to step S03.

[0033] In step S03, it is determined whether MT mode is selected by the mode selection switch 42. Control of the electric motor 2 in EV mode continues until MT mode is selected. If MT mode is selected, the procedure proceeds to step S04.

[0034] In step S04, the connection destination of the changeover switch 560 is switched from the motor torque command map 550 to the requested motor torque calculation unit 540. As a result, the control mode switches from EV mode to MT mode.

[0035] 2-2. MT Vehicle Models 2-2-1. Overview Next, the MT vehicle model 530 will be described. Figure 5 is a block diagram showing an example of the MT vehicle model 530. The MT vehicle model 530 consists of an engine model 531, a clutch model 532, an MT model 533, an axle / drive wheel model 534, and a PCU model 535. In the engine model 531, a virtual engine is modeled. In this embodiment, the virtual engine is a spark-ignition engine whose torque is controlled by the throttle opening. In the clutch model 532, a virtual clutch is modeled. In the MT model 533, a virtual SMT is modeled. In the axle / drive wheel model 534, a virtual torque transmission system from the axle to the drive wheel is modeled. And in the PCU model 535, some functions of a virtual plant control unit (PCU) that integrates and controls the virtual engine, virtual clutch, and virtual SMT are modeled. Each model may be represented, for example, by a calculation formula or by a map.

[0036] Input and output of calculation results are performed between each model. In addition, the accelerator opening Pap, upshift signal Su, and downshift signal Sd input to the MT vehicle model 530 are used in the PCU model 535. The vehicle speed Vw (or wheel speed) is used in multiple models. In the MT vehicle model 530, the drive wheel torque Tw and virtual engine speed Ne are calculated based on these input signals.

[0037] 2-2-2. PCU Model The PCU model 535 calculates the virtual throttle opening of the virtual engine, the virtual clutch opening of the virtual clutch, and the virtual gear position of the virtual SMT. The PCU model 535 consists of a throttle opening model for calculating the virtual throttle opening, a clutch opening model for calculating the virtual clutch opening, and a gear position model for calculating the virtual gear position.

[0038] The throttle position model receives the accelerator position Pap, the upshift signal Su, and the downshift signal Sd as inputs and outputs a virtual throttle position TA. In the throttle position model, the virtual throttle position TA is associated with the accelerator position Pap, and as the accelerator position Pap increases, the virtual throttle position TA increases. However, when the upshift signal Su and the downshift signal Sd are input, the virtual throttle position TA is temporarily reduced regardless of the accelerator position Pap. This means that when a shift operation is performed on the pseudo-paddle shifter 26, the virtual throttle is temporarily closed. The virtual throttle position TA output from the throttle position model is input to the engine model 531.

[0039] The clutch opening model receives the upshift signal Su and the downshift signal Sd as inputs and outputs a virtual clutch opening CP. The virtual clutch opening CP is basically set to zero percent. That is, the basic state of the virtual clutch is engaged. When the upshift signal Su and the downshift signal Sd are input, the virtual clutch opening CP is temporarily set to 0%. This means that when a shift operation is performed on the pseudo paddle shifter 26, the virtual clutch is temporarily released. The vehicle speed Vw and the virtual engine speed are used to calculate the virtual clutch opening CP when the virtual clutch is engaged. The clutch opening model calculates the virtual clutch opening CP based on the rotational speed difference so that the rotational speed of the input shaft of the virtual SMT calculated from the vehicle speed Vw and the virtual engine speed are smoothly matched. The virtual clutch opening CP output from the clutch opening model is input to the clutch model 532.

[0040] The gear stage model receives an upshift signal Su and a downshift signal Sd as inputs and outputs a virtual gear stage GP. The number of gear stages in the virtual SMT is N (where N is a natural number greater than or equal to 2). The virtual gear stage GP is raised by one stage each time an upshift signal Su is input. However, when the virtual gear stage GP is at the Nth stage, it remains at the Nth stage even when an upshift signal Su is input. Also, the virtual gear stage GP is lowered by one stage each time a downshift signal Sd is input. However, when the virtual gear stage GP is at the 1st stage, it remains at the 1st stage even when a downshift signal Sd is input. The virtual gear stage GP output from the gear stage model is input to the MT model 533.

[0041] 2-2-3. Engine Models Engine model 531 calculates the virtual engine rotational speed Ne and the virtual engine output torque Teout. Engine model 531 consists of a model for calculating the virtual engine rotational speed Ne and a model for calculating the virtual engine output torque Teout. For example, the model represented by equation (1) below is used to calculate the virtual engine rotational speed Ne. In equation (1), the virtual engine rotational speed Ne is calculated from the rotational speed Nw of the wheel 8, the overall reduction ratio R, and the slip ratio Rslip of the virtual clutch.

[0042]

number

[0043] In equation (1), the rotational speed Nw of wheel 8 is detected by the wheel speed sensor 30. The overall reduction ratio R is calculated from the gear ratio (shift ratio) r calculated in the MT model 533 described later and the reduction ratio specified in the axle / drive wheel model 534. The slip ratio Rslip is calculated in the clutch model 532 described later.

[0044] However, equation (1) is the formula for calculating the virtual engine speed Ne when the virtual engine and virtual SMT are connected by a virtual clutch. When the virtual clutch is disengaged, the virtual engine torque Te generated by the virtual engine can be considered to be used to increase the virtual engine speed Ne. The virtual engine torque Te is the torque obtained by adding the torque due to the moment of inertia to the virtual engine output torque Teout. When the virtual clutch is disengaged, the virtual engine output torque Teout is zero. Therefore, when the virtual clutch is disengaged, engine model 531 calculates the virtual engine speed Ne using the virtual engine torque Te and the moment of inertia J of the virtual engine by the following equation (2). A map with the virtual throttle opening TA as a parameter is used to calculate the virtual engine torque Te.

[0045]

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[0046] In addition, during idling in a clutchless manual transmission vehicle, idle speed control is performed to maintain the engine speed at a constant speed. Therefore, when the virtual clutch is disengaged, the vehicle speed is 0, and the virtual throttle opening TA is 0%, the engine model 531 calculates the virtual engine speed Ne as a predetermined idling speed (for example, 1000 rpm). When the driver depresses the accelerator pedal 22 while stationary to rev the engine, the idling speed is used as the initial value of the virtual engine speed Ne calculated by equation (2).

[0047] The engine model 531 calculates the virtual engine output torque Teout from the virtual engine rotational speed Ne and the virtual throttle opening TA. For example, a map like the one shown in Figure 6 is used to calculate the virtual engine output torque Teout. This map defines the relationship between the virtual throttle opening TA, the virtual engine rotational speed Ne, and the virtual engine output torque Teout in a steady state. In this map, the virtual engine output torque Teout is given for each virtual throttle opening TA relative to the virtual engine rotational speed Ne. The torque characteristics shown in Figure 6 can be set to represent a naturally aspirated engine or a turbocharged engine. Furthermore, the torque characteristics shown in Figure 6 can also be set to represent a diesel engine by replacing the virtual throttle opening TA with the virtual fuel injection amount. The virtual engine output torque Teout calculated by the engine model 531 is input to the clutch model 532.

[0048] 2-2-4. Clutch Model The clutch model 532 calculates the torque transmission gain k. The torque transmission gain k is a gain used to calculate the degree of torque transmission of the virtual clutch according to the virtual clutch opening CP. The clutch model 532 has a map, for example, as shown in Figure 6. In this map, the torque transmission gain k is given for the virtual clutch opening CP. In Figure 6, the torque transmission gain k is given such that the virtual clutch opening CP is 1 in the range from CP0 to CP1, decreases monotonically with a constant slope from CP1 to CP2 to 0, and is 0 in the range from CP2 to CP3. Here, CP0 corresponds to a clutch opening of 0%, and CP3 corresponds to a clutch opening of 100%. The range from CP0 to CP1 and the range from CP2 to CP3 are dead zones in which the torque transmission gain k does not change with respect to the virtual clutch opening CP.

[0049] The clutch model 532 calculates the clutch output torque Tcout using the torque transfer gain k. The clutch output torque Tcout is the torque output from the virtual clutch. For example, the clutch model 532 calculates the clutch output torque Tcout from the virtual engine output torque Teout and the torque transfer gain k using the following equation (3). The clutch output torque Tcout calculated by the clutch model 532 is input to the MT model 533.

[0050]

number

[0051] Furthermore, clutch model 532 calculates the slip ratio Rslip. The slip ratio Rslip is used in the calculation of the virtual engine speed Ne in engine model 531. Similar to the torque transmission gain k, a map can be used to calculate the slip ratio Rslip, where Rslip is given in relation to the clutch pedal depression amount Pc. Alternatively, the slip ratio Rslip may be calculated from the torque transmission gain k using the following equation (4), which expresses the relationship between the slip ratio Rslip and the torque transmission gain.

[0052]

number

[0053] 2-2-5. MT Model The MT model 533 calculates the gear ratio (shift ratio) r. The gear ratio r is determined by the virtual gear stage GP in the virtual SMT. The MT model 533 has a map, for example, as shown in Figure 6. In this map, the gear ratio r is given for the virtual gear stage GP. As shown in Figure 6, the larger the virtual gear stage GP, the smaller the gear ratio r becomes.

[0054] 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 SMT. MT model 533 calculates the transmission output torque Tgout from the clutch output torque Tcout and the gear ratio r, for example, using equation (5). The transmission output torque Tgout calculated by MT model 533 is input to the axle / drive wheel model 534.

[0055]

number

[0056] 2-2-5. Axle and 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 SMT to the drive wheel 8. The value obtained by multiplying the reduction ratio rr by the gear ratio r is the aforementioned overall reduction ratio R. The axle / drive wheel model 534 calculates the drive wheel torque Tw from the transmission output torque Tgout and the reduction ratio rr using, for example, the following equation (6). The drive wheel torque Tw calculated by the axle / drive wheel model 534 is output to the requested motor torque calculation unit 540.

[0057]

number

[0058] 3. Others In the above embodiment, a lever-type pseudo-shifter may be provided instead of a paddle-type pseudo-shifter. The lever-type pseudo-shifter is configured to output an upshift signal when the shift lever is moved forward and a downshift signal when the shift lever is moved backward.

[0059] In the above embodiment, a pseudo-sequential shifter may be replaced with a pseudo-H-type shifter and a pseudo-clutch pedal. In that case, the clutch model of the MT vehicle model should calculate the torque transmission gain according to the amount the pseudo-clutch pedal is pressed. Also, the MT model of the MT vehicle model should calculate the gear ratio according to the shift position of the pseudo-H-type shifter.

[0060] The electric vehicle 10 according to the above embodiment does not have a transmission. However, the present invention is also applicable to electric vehicles equipped with a stepped or continuously variable automatic transmission. In this case, the powertrain consisting of the electric motor and the automatic transmission should be controlled to output the motor torque calculated in the MT vehicle model.

[0061] The motor torque control technology disclosed herein is not limited to battery electric vehicles, but is broadly applicable to any electric vehicle that uses an electric motor as a power source for driving. [Explanation of Symbols]

[0062] 2 electric motors, 10 electric vehicles, 16 inverters, 22 accelerator pedals, 26 simulated paddle shifters, 42 mode selection switches, 46 start switches, 50 control devices

Claims

[Claim 1] An electric vehicle that uses an electric motor as a power source for driving, The accelerator pedal and Shifter and, A mode selection device that selects either a first mode or a second mode as the control mode of the electric motor according to the driver's mode selection operation, The system includes a control device that controls the electric motor according to the control mode selected by the mode selection device, The control device is When controlling the electric motor in the first mode, the motor torque of the electric motor is changed according to the opening degree of the accelerator pedal, without regard to the shift operation of the shifter. When controlling the electric motor in the second mode described above, The virtual gear position is determined according to the shift operation of the shifter. The larger the gear ratio of the virtual gear stage, the greater the rate of change of the motor torque with respect to the opening of the accelerator pedal. In the range of the accelerator pedal opening from 0% to the first opening, the motor torque is set to a negative torque, and the magnitude of the negative motor torque increases as the virtual gear stage has a larger gear ratio. In the range from a second opening (where the accelerator pedal opening is greater than the first opening) to 100%, the motor torque is set to a positive torque, and the magnitude of the positive motor torque increases as the virtual gear stage has a larger gear ratio. The mode selection device is When the electric vehicle is started, the first mode is automatically selected. The system is configured to switch the control mode from the first mode to the second mode in response to the driver's selection operation for the second mode. An electric vehicle characterized by the following features.

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