Battery electric vehicle

Abstract

The invention relates to a battery electric vehicle. A battery electric vehicle includes an electric motor as a drive source. A battery-powered vehicle includes an accelerator pedal, a dummy shifter, and a controller. The dummy shifter emulates a shifter for performing a shift operation of a manual transmission internal combustion engine vehicle. The controller is configured to change a relationship between a vehicle speed of the battery electric vehicle, an accelerator operation amount of the accelerator pedal, and a torque of the electric motor in response to an operation of the dummy shifter. The controller is configured to change the relationship within a predetermined time after operating the dummy shifter.

Description

Technical Field

[0001] The present disclosure relates to a battery electric vehicle including an electric motor as a drive source. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2022-030838 (JP 2022-030838 A) discloses a battery electric vehicle that can simulate a manual shifting operation of a vehicle equipped with a manual transmission and powered by an internal combustion engine (hereinafter referred to as a "manual transmission internal combustion engine vehicle") by controlling an electric motor. The battery electric vehicle disclosed in this publication includes a vehicle model that simulates a manual transmission internal combustion engine vehicle and a driver model that simulates a typical driver. The vehicle model includes an engine model, a clutch model, and a manual transmission model. The driver model calculates the amount of depression of the clutch pedal of a virtual clutch simulated by the clutch model based on the rotational speed difference between the rotational speed of the input shaft of a virtual manual transmission simulated by the manual transmission model and the rotational speed of a virtual engine simulated by the engine model.

[0003] In the battery electric vehicle disclosed in the above publication, the virtual clutch cannot be engaged unless the rotational speed difference calculated by the driver model is reduced, and the shifting operation will not be completed according to the calculation of the vehicle model. During this time, the battery electric vehicle simulates the behavior of a manual transmission internal combustion engine vehicle with the clutch disengaged. Therefore, the longer it takes to complete the shifting operation, the more uncomfortable the driver feels. Summary of the Invention

[0004] The present disclosure provides a battery electric vehicle that can simulate a shifting operation of a manual transmission internal combustion engine vehicle. The battery electric vehicle reduces the possibility that a driver may feel uncomfortable due to a long shifting time.

[0005] A battery electric vehicle according to an embodiment of the present disclosure includes an electric motor as a drive source. The battery electric vehicle includes an accelerator pedal, a pseudo-shifter, and a controller. The pseudo-shifter mimics a shifter for performing a shifting operation of a manual transmission internal combustion engine vehicle. The controller is configured to change the relationship among the vehicle speed of the battery electric vehicle, the accelerator operation amount of the accelerator pedal, and the torque of the electric motor in response to an operation of the pseudo-shifter. The controller is configured to change the relationship within a predetermined time after operating the pseudo-shifter.

[0006] In an embodiment of the present disclosure, the controller may be configured as follows.

[0007] The controller may include: a memory that stores a vehicle model for modeling a virtual vehicle; and a processing circuit coupled to the memory and configured to execute the vehicle model. The vehicle model may include: a driver model for modeling a typical driver; an engine model for modeling a virtual internal combustion engine; a clutch model for modeling a virtual clutch; and a transmission model for modeling a virtual manual transmission.

[0008] The driver model may be configured to calculate a virtual accelerator operation amount of the virtual internal combustion engine, a virtual clutch operation amount of the virtual clutch, and a virtual gear of the virtual manual transmission based on an accelerator operation amount of an accelerator pedal, a shift position of a pseudo-shifter, a vehicle speed of a battery electric vehicle, and a virtual engine speed of the virtual internal combustion engine. The engine model may be configured to calculate a virtual engine speed based on the virtual gear and the vehicle speed when the virtual clutch is in an engaged state, and may be configured to calculate a virtual engine speed based on the virtual accelerator operation amount and a virtual moment of inertia of the virtual internal combustion engine when the virtual clutch is in a disengaged state.

[0009] The driver model may be configured to calculate a virtual clutch operation amount to engage the virtual clutch when a rotational speed difference between the virtual engine speed and a virtual input shaft speed of the virtual manual transmission falls within a predetermined range after a start of a shift of the virtual manual transmission. The driver model may be configured to calculate a virtual clutch operation amount to engage the virtual clutch when a time elapsed since the start of the shift of the virtual manual transmission exceeds a predetermined standby time, regardless of the rotational speed difference between the virtual engine speed and the virtual input shaft speed.

[0010] In a battery electric vehicle according to an embodiment of the present disclosure, when a driver operates a pseudo-shifter, a relationship among a vehicle speed of the battery electric vehicle, an accelerator operation amount of an accelerator pedal, and a torque of an electric motor always changes within a predetermined time. Therefore, when simulating a shift operation of a manual transmission internal combustion engine vehicle, the shift operation will always be completed within a predetermined time from the operation of the pseudo-shifter. This reduces a possibility that a driver may feel uncomfortable due to a long shift time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0012] Figure 1 shows a configuration of a battery electric vehicle according to an embodiment of the present disclosure;

[0013] Figure 2 shows a configuration of a vehicle model included in a controller;

[0014] Figure 3 Shows the state determination process performed by the driver model;

[0015] Figure 4 Shows the details of the shift state determination process performed by the driver model;

[0016] Figure 5 Is a flowchart showing the process of the backup shift process; and

[0017] Figure 6 Shows a specific example of the shift control performed by the controller. Detailed Description of the Invention

[0018] 1. Configuration of the powertrain of the battery electric vehicle

[0019] Figure 1 Schematically shows the configuration of a battery electric vehicle 100 according to an embodiment of the present disclosure. First, reference will be made to Figure 1 Describe the configuration of the powertrain of the battery electric vehicle 100.

[0020] The battery electric vehicle 100 includes two electric motors (M) 4F, 4R at the front and rear as traction power sources. The electric motors 4F, 4R are, for example, three-phase alternating current (AC) motors. The front electric motor 4F is connected to the front drive shaft 5F that drives the front wheels 6F. The rear electric motor 4R is connected to the rear drive shaft 5R that drives the rear wheels 6R. The front wheels 6F are suspended on the left and right front suspensions 7F that are independently electronically controlled. The rear wheels 6R are suspended on the left and right rear suspensions 7R that are independently electronically controlled.

[0021] The front electric motor 4F and the rear electric motor 4R are respectively equipped with inverters (INV) 3F, 3R. The front inverter 3F and the rear inverter 3R are each connected to the battery (BATT) 2. That is, the battery electric vehicle 100 is a battery electric vehicle (BEV) that travels relying on the electric energy stored in the battery 2. The inverters 3F, 3R are, for example, voltage inverters, and respectively control the torque of the electric motors 4F, 4R through pulse width modulation (PWM) control.

[0022] 2. Configuration of the control system of the battery electric vehicle

[0023] Next, reference will be made to Figure 1 Describe the configuration of the control system of the battery electric vehicle 100.

[0024] The battery electric vehicle 100 includes a vehicle speed sensor 11. At least one of wheel speed sensors (not shown) mounted on the left and right front wheels 6F and the left and right rear wheels 6R serves as the vehicle speed sensor 11. The battery electric vehicle 100 also includes an accelerator pedal stroke sensor 12. The accelerator pedal stroke sensor 12 is provided for the accelerator pedal 22 and outputs a signal indicating the depression amount of the accelerator pedal 22 (i.e., the accelerator operation amount). The battery electric vehicle 100 also includes a brake pedal stroke sensor 13. The brake pedal stroke sensor 13 is provided for the brake pedal 23 and outputs a signal indicating the depression amount of the brake pedal 23 (i.e., the brake operation amount).

[0025] The accelerator pedal 22 and the brake pedal 23 are driving operation members for driving the battery electric vehicle 100. In addition to these driving operation members, the battery electric vehicle 100 also includes a pseudo-shifter 24 that mimics a shifter for performing a shifting operation of a manual transmission internal combustion engine vehicle. The pseudo-shifter 24 may be a pseudo-sequential shifter that mimics a sequential shifter such as a paddle shifter, or may be a pseudo-H shifter that mimics an H-type shifter. Here, it is assumed that the pseudo-shifter 24 is a pseudo-paddle shifter that mimics a paddle shifter.

[0026] The pseudo-shifter 24 has a structure that mimics paddle shifters attached to the steering wheel or the steering shaft and allows the left and right paddles to move independently of each other. The pseudo-shifter 24 is provided with a shift position sensor 14. The shift position sensor 14 outputs an upshift signal when the right paddle is pulled and outputs a downshift signal when the left paddle is pulled.

[0027] The battery electric vehicle 100 also includes a human machine interface (HMI) 20 and a pseudo-tachometer 21 as an interface for communicating with the driver. The HMI 20 includes a touch panel display. The HMI 20 displays information on the touch panel display and receives input from the driver through a touch operation on the touch panel display. The pseudo-tachometer 21 displays a virtual engine speed that will be described later to the driver.

[0028] The battery electric vehicle 100 includes a controller 101. Sensors and devices to be controlled mounted on the battery electric vehicle 100 are connected to the controller 101 via an in-vehicle network. In addition to the vehicle speed sensor 11, the accelerator pedal stroke sensor 12, the brake pedal stroke sensor 13, and the shift position sensor 14, various other sensors are also mounted on the battery electric vehicle 100.

[0029] The controller 101 is typically an electronic control unit (ECU). The controller 101 can be a combination of multiple ECUs. The controller 101 includes at least a processing circuit 102 and a memory 103. For example, the processing circuit 102 can be a central processing unit (CPU), or a combination of a CPU and a field programmable gate array (FPGA). The memory 103 includes a random access memory (RAM) for temporarily recording data and a read only memory (ROM) for storing a program 104 executable by the processing circuit 102 and various types of data 105 related to the program. The memory 103 can be included in the processing circuit 102. The program 104 consists of multiple instruction codes. The processing circuit 102 reads the program 104 and the data 105 from the memory 103, executes the program 104, and generates a control signal based on the signals acquired from the sensors. The controller 101 can include one processing circuit 102, or can include multiple processing circuits 102.

[0030] 3. Functions of the Controller

[0031] 3-1. Control Modes

[0032] The controller 101 is capable of controlling the battery electric vehicle 100 in various control modes. The driver can select his / her own control mode by performing a touch operation on the touch panel display of the HMI 20. Specifically, when a touch operation is performed on the touch panel display of the HMI 20, one or more programs 104 associated with the touch operation are read from the memory 103 and executed by the processing circuit 102.

[0033] The control modes selectable via the HMI 20 include an automatic mode and a manual mode. The automatic mode is a control mode in which the battery electric vehicle 100 is driven as a normal BEV. In the automatic mode, the driver can basically drive the battery electric vehicle 100 only by operating the accelerator pedal 22, the brake pedal 23, and the steering wheel (not shown). In the automatic mode, the shifting operation of the pseudo-shifter 24 is disabled. The manual mode is a control mode in which the battery electric vehicle 100 is operated like an internal combustion engine vehicle with a manual transmission. In the manual mode, the operation when the gear ratio changes in a manual transmission is reproduced by the shifting operation of the pseudo-shifter 24.

[0034] 3-2. Vehicle Model

[0035] When the processing circuit 102 executes one or more torque control programs 104 stored in the memory 103, the controller 101 functions as a torque controller. A control mode signal is input from the HMI 20 to the controller 101 that functions as a torque controller. The control mode signal includes information about the control mode selected by the driver. When the control mode is switched to the manual mode, the controller 101 calculates the drive wheel torque to be generated by the drive wheels using a vehicle model, and generates a motor torque command value to be given to the inverters 3F, 3R based on the drive wheel torque.

[0036] Figure 2 The configuration of the vehicle model MOD01 included in the controller 101 is shown. The vehicle model MOD01 is composed of a driver model MOD10, an engine model MOD11, a clutch model MOD12, a manual transmission model MOD13, and an axle / drive wheel model MOD14. The internal combustion engine virtually implemented by the vehicle model MOD01 will be referred to as the "virtual internal combustion engine", the clutch virtually implemented by the vehicle model MOD01 will be referred to as the "virtual clutch", and the manual transmission virtually implemented by the vehicle model MOD01 will be referred to as the "virtual manual transmission". The manual transmission internal combustion engine vehicle virtually implemented by the combination of these will be referred to as the "virtual vehicle".

[0037] The engine model MOD11 models the virtual internal combustion engine. The clutch model MOD12 models the virtual clutch. The manual transmission model MOD13 models the virtual manual transmission. The axle / drive wheel model MOD14 models the virtual torque transmission system from the axle to the drive wheels. The driver model MOD10 models a typical driver. The typical driver is an experienced driver for driving a manual transmission internal combustion engine vehicle. The driver model MOD10 can also be said to be a model of a virtual powertrain control unit (PCU) that integrally controls the virtual internal combustion engine, the virtual clutch, and the virtual manual transmission. The calculation results are transmitted between these models.

[0038] The engine model MOD11 calculates the virtual engine speed. Different calculation methods are used to calculate the virtual engine speed according to whether the virtual clutch is in the engaged state or the disengaged state. When the virtual clutch is in the engaged state, the virtual engine speed is calculated based on the vehicle speed, the virtual overall reduction ratio, and the slip ratio of the virtual clutch. The vehicle speed is obtained from the signal of the vehicle speed sensor 11. Among them, the virtual overall reduction ratio is a value obtained by multiplying the virtual transmission ratio of the virtual manual transmission by the virtual reduction ratio determined by the mechanical structure from the virtual manual transmission to the drive wheels. When the virtual clutch is in the disengaged state, the virtual accelerator operation amount and the virtual moment of inertia of the virtual internal combustion engine are used to calculate the virtual engine speed. For example, the virtual engine torque can be calculated based on the current virtual engine speed and the current virtual accelerator operation amount, and the change amount of the virtual engine speed after a unit time can be calculated based on the virtual engine torque and the virtual moment of inertia.

[0039] The engine model MOD11 calculates the virtual engine torque. The virtual engine torque is calculated based on the virtual engine speed and the virtual accelerator operation amount using a map such as the curve shown in Figure 2 . The virtual accelerator operation amount is calculated by the driver model MOD10. The engine model MOD11 defines the relationship between the virtual engine speed and the virtual engine torque for each virtual accelerator operation amount. The virtual engine torque is input from the engine model MOD11 to the clutch model MOD12.

[0040] The clutch model MOD12 calculates the virtual torque transfer gain. The virtual torque transfer gain is a gain used to calculate the torque transfer degree of the virtual clutch. The virtual torque transfer gain is calculated from the virtual clutch operation amount using a map such as the curve shown in Figure 2 . The virtual clutch operation amount is calculated by the driver model MOD10. When the virtual clutch is in the engaged state, the clutch model MOD12 calculates the virtual clutch torque using the virtual torque transfer gain. The virtual clutch torque is input from the clutch model MOD12 to the manual transmission model MOD13.

[0041] The manual transmission model MOD13 calculates the virtual transmission ratio. The virtual transmission ratio is the transmission ratio determined by the virtual gear position in the virtual manual transmission. The virtual gear ratio is calculated from the virtual gear position using a map such as the curve shown in Figure 2 . The virtual gear position is calculated by the driver model MOD10. The manual transmission model MOD13 calculates the virtual transmission torque using the virtual transmission ratio and the virtual clutch torque. The virtual transmission torque is input from the manual transmission model MOD13 to the axle / drive wheel model MOD14.

[0042] The axle / drive wheel model MOD14 calculates the drive wheel torque. The drive wheel torque is calculated using the virtual transmission torque and the virtual reduction ratio from the virtual manual transmission to the drive wheels. The drive wheel torque is the sum of the torques applied to the left and right front wheels 6F and the left and right rear wheels 6R. The torque generated by the front electric motor 4F is calculated by multiplying the drive wheel torque by the torque distribution ratio of the front wheels 6F and the reduction ratio from the output shaft of the front electric motor 4F to the front wheels 6F. The torque generated by the rear electric motor 4R is calculated by multiplying the drive wheel torque by the torque distribution ratio of the rear wheels 6R and the reduction ratio from the output shaft of the rear electric motor 4R to the rear wheels 6R.

[0043] The driver model MOD10 calculates the virtual accelerator operation amount of the virtual internal combustion engine, the virtual clutch operation amount of the virtual clutch, and the virtual gear position of the virtual manual transmission. To calculate these virtual operation amounts, the driver model MOD10 performs state determination processing P10, virtual accelerator operation amount calculation processing P21, virtual clutch operation amount calculation processing P22, and virtual gear position calculation processing P23.

[0044] In the state determination processing P10, the vehicle state and the shift state of the virtual vehicle are determined. The state determination processing P10 will be described in detail later. The shift state determined in the state determination processing P10 is used in the virtual accelerator operation amount calculation processing P21, the virtual clutch operation amount calculation processing P22, and the virtual gear position calculation processing P23.

[0045] In the virtual accelerator operation amount calculation processing P21, the virtual accelerator operation amount is calculated based on the accelerator operation amount obtained by the accelerator pedal stroke sensor 12 and the shift state of the virtual vehicle determined in the state determination processing P10. The accelerator operation amount obtained by the accelerator pedal stroke sensor 12 represents the magnitude of the torque requirement for the electric motors 4F and 4R. The virtual accelerator operation amount represents the magnitude of the torque requirement for the virtual internal combustion engine of the virtual vehicle. The virtual accelerator operation amount calculation processing P21 can be said to be a process of correcting the accelerator operation amount obtained by the accelerator pedal stroke sensor 12 to the accelerator operation amount of the virtual internal combustion engine. The virtual accelerator operation amount calculated in the virtual accelerator operation amount calculation processing P21 is input to the engine model MOD11.

[0046] In the virtual clutch operation amount calculation process P22, the virtual clutch operation amount is calculated based on the shift state of the virtual vehicle determined in the state determination process P10. The virtual clutch operation amount is basically set to 0%. That is to say, the basic state of the virtual clutch is the engaged state. When an upshift signal or a downshift signal is input from the shift position sensor 14, the virtual clutch operation amount is temporarily set to 100%. This means that when the shift operation of the pseudo-shifter 24 is performed, the virtual clutch is temporarily disengaged. The virtual clutch operation amount calculated in the virtual clutch operation amount calculation process P22 is input to the clutch model MOD12.

[0047] In the virtual gear calculation process P23, the virtual gear is calculated based on the shift position obtained by the shift position sensor 14 and the shift state of the virtual vehicle determined in the state determination process P10. The number of virtual gears is the sum of the number of positions of the pseudo-shifter 24 and the neutral gear. The virtual gear calculated in the virtual gear calculation process P23 is input to the manual transmission model MOD13.

[0048] Figure 3 The state determination process P10 is shown. The state determination process P10 includes a vehicle state determination process P11 and a shift state determination process P12. In these two processes P11, P12, the main process is the vehicle state determination process P11. When a predetermined condition is satisfied in the vehicle state determination process P11, the shift state determination process P12 is executed.

[0049] In the vehicle state determination process P11, steps S11, S12, and S13 are executed. In step S11, it is determined whether there is a shift request from the driver. When an upshift signal or a downshift signal is input from the shift position sensor 14, it is determined that the driver is requesting a shift. In response to the shift request from the driver, the shift starts, and the shift flag indicating that the virtual vehicle is shifting is switched from off (OFF) to on (ON).

[0050] When it is determined that there is a shift request from the driver, in step S12, it is determined whether the virtual vehicle is in a shift state. When it is determined that there is no shift request from the driver, in step S13, it is determined that the virtual vehicle is in a state other than the shift state. The state other than the shift state includes, for example, the state where the pseudo-shifter 24 is not operated. When it is determined that the virtual vehicle is in a shift state, the shift state determination process P12 is executed.

[0051] In the shift state determination process P12, it is determined which of the shift states M1 to M6 the virtual vehicle is in. In the shift state M1, the virtual accelerator operation amount changes from the accelerator operation amount requested by the driver to zero. The accelerator operation amount requested by the driver is the accelerator operation amount obtained by the accelerator pedal stroke sensor 12. The transition condition E1 from the shift state M1 to the shift state M2 is that the virtual accelerator operation amount becomes zero. In the shift state M2, the virtual clutch is disengaged. That is, the virtual clutch operation amount changes to 100%. The transition condition E2 from the shift state M2 to the shift state M3 is that the disengagement of the virtual clutch is completed. In the shift state M3, after the shift operation, the virtual gear changes to the virtual gear corresponding to the shift position. This change of the virtual gear is made via the neutral gear.

[0052] When the change of the virtual gear is a downshift, the shift state M3 transitions to the shift state M5 via the shift state M4. The transition condition E3 from the shift state M3 to the shift state M4 is that the shift to the changed virtual gear is completed. In the shift state M4, the virtual engine speed and the virtual input shaft speed of the virtual manual transmission are synchronized. The transition condition E5 from the shift state M4 to the shift state M5 is that the speed difference between the virtual engine speed and the virtual input shaft speed falls within a predetermined range. When the change of the virtual gear is an upshift, the shift state M3 directly transitions to the shift state M5. The transition condition E4 from the shift state M3 to the shift state M5 is that the speed difference between the virtual engine speed and the virtual input shaft speed falls within a predetermined range.

[0053] In the shift state M5, the virtual clutch is engaged. That is, the virtual clutch operation amount becomes 0%. The transition condition E6 from the shift state M5 to the shift state M6 is that the engagement of the virtual clutch is completed. In the shift state M6, the virtual accelerator operation amount returns to the accelerator operation amount requested by the driver, that is, the accelerator operation amount obtained by the accelerator pedal stroke sensor 12. The transition condition E7 from the shift state M6 to the shift state M1 is that the virtual accelerator operation amount increases to the accelerator operation amount requested by the driver.

[0054] Figure 4 The details of the shift state determination process P12 are shown. Each of the shift states M1 to M6 can be represented by the virtual accelerator operation amount, the virtual clutch operation amount, and the virtual gear.

[0055] In the shift state M1, the virtual accelerator operation amount gradually changes from the operation amount requested by the driver (user requested operation amount) to 0%. The virtual clutch operation amount is set to the engagement operation amount, that is, the operation amount corresponding to the engaged state. The virtual gear remains at the current gear.

[0056] In the shift state M2, the virtual accelerator operation amount is set to 0%. The virtual clutch operation amount gradually changes from the engagement operation amount to the disengagement operation amount, i.e., the operation amount corresponding to the disengagement state. The virtual gear position remains at the current gear position.

[0057] In the shift state M3, the virtual accelerator operation amount is set to 0%. The virtual clutch operation amount is set to the disengagement operation amount. The virtual gear position first changes from the current gear position to the neutral position and then to the gear position requested by the driver.

[0058] In the shift state M4, a brief blipping is performed to temporarily increase the virtual accelerator operation amount, thereby increasing the virtual engine speed. The virtual clutch operation amount is set to the disengagement operation amount. The virtual gear position is set to the requested gear position.

[0059] In the shift state M5, the virtual accelerator operation amount is set to 0%. The virtual clutch operation amount gradually changes from the disengagement operation amount to the engagement operation amount. The virtual gear position is set to the requested gear position.

[0060] In the shift state M6, the virtual accelerator operation amount gradually changes from 0% to the operation amount requested by the user. The virtual clutch operation amount is set to the engagement operation amount. The virtual gear position is set to the requested gear position. When the virtual accelerator operation amount returns to the accelerator operation amount requested by the driver, the flag indicating that the virtual vehicle is shifting gears switches from ON to OFF.

[0061] As described above, the virtual accelerator operation amount calculation process P21 is executed according to the state of the virtual accelerator operation amount defined by each of the shift states M1 to M6. The virtual clutch operation amount calculation process P22 is executed according to the state of the virtual clutch operation amount defined by each of the shift states M1 to M6. The virtual gear position calculation process P23 is executed according to the state of the virtual gear position defined by each of the shift states M1 to M6.

[0062] 4. Backup Shift Process

[0063] In the above shift state determination process P12, the timing for engaging the virtual clutch is determined based on the rotational speed difference between the virtual engine speed and the virtual input shaft speed. However, during an upshift, it is expected that the rotational speed difference will not decrease rapidly, and it takes time to meet the transition condition E4. Similarly, during a downshift, it is expected that the rotational speed difference will not decrease rapidly, and it takes time to meet the transition condition E5. Before the transition condition E4 or E5 is met, the virtual clutch cannot be engaged, and the shift operation in the virtual vehicle will not be completed. The longer it takes to complete the shift operation, the more uncomfortable the driver will feel.

[0064] As a measure to reduce or prevent an increase in shift time, the controller 101 performs an alternative shift process described below. More specifically, the alternative shift process is incorporated into the shift state determination process P12.

[0065] Figure 5 is a flowchart showing the flow of the alternative shift process. In step S101, it is determined whether there is a shift request from the driver. When an upshift signal or a downshift signal is input from the shift position sensor 14, it is determined that the driver is requesting a shift. In response to the shift request from the driver, shifting starts, and the shift flag is switched from OFF to ON.

[0066] When it is determined that there is a shift request from the driver, an alternative time is set in step S102. The length of the alternative time is preset and stored as data 105 in the memory 103. Then in step S103, it is determined whether the shift time has exceeded the alternative time. For example, the shift time can be defined as the time elapsed since the virtual gear shifted from the gear before the start of shifting to neutral. Alternatively, the shift time can be the time elapsed since the virtual gear shifted from neutral to the requested gear.

[0067] The process proceeds to step S104 until the shift time exceeds the alternative time. In step S104, normal synchronization determination is performed. In normal synchronization determination, when the shift conditions E4 or E5 are satisfied, it is determined that the virtual engine speed and the virtual input shaft speed are synchronized. That is, when the speed difference between the virtual engine speed and the virtual input shaft speed falls within a predetermined range, it is determined that the virtual engine speed and the virtual input shaft speed are synchronized. When normal synchronization determination is established, the virtual clutch operation amount calculation process P22 calculates the virtual clutch operation amount to engage the virtual clutch. Thus, the shift is completed, and the shift flag is switched from ON to OFF.

[0068] When the shift time exceeds the alternative time, the process proceeds to step S105. In step S105, forced synchronization determination is performed. In forced synchronization determination, even when the speed difference between the virtual engine speed and the virtual input shaft speed has not fallen within the predetermined range, it is forcibly determined that the virtual engine speed and the virtual input shaft speed are synchronized. When forced synchronization determination is established, the virtual clutch operation amount calculation process P22 calculates the virtual clutch operation amount to engage the virtual clutch regardless of the speed difference. Thus, the shift is completed, and the shift flag is switched from ON to OFF.

[0069] When the shift flag is switched from ON to OFF, the process advances from step S101 to step S106. In step S106, the shift time is reset.

[0070] Finally, reference will be made to Figure 6Describe a specific example of shift control including a standby shift process executed by the controller 101.

[0071] According to Figure 6 the timing chart shown, an upshift signal is input from the shift position sensor 14 to the controller 101 at time t1. In response to the input of the upshift signal, the virtual clutch operation amount starts to change from the engagement operation amount to the disengagement operation amount at time t2. As the virtual clutch operation amount gets closer to the disengagement operation amount, the virtual engine speed decreases, and the longitudinal acceleration acting on the battery electric vehicle 100 also decreases. At time t3, the virtual clutch operation amount becomes exactly equal to the disengagement operation amount, and in response thereto, the virtual gear is switched from the current gear (i.e., the Nth gear) to neutral.

[0072] At time t3 when the virtual gear is switched to neutral, the measurement of the shift time starts. At time t4 when a specific time has elapsed since the virtual gear was switched from the Nth gear to neutral, the virtual gear is switched from neutral to the gear requested by the driver ( Figure 6 the (N + 1)th gear in the example shown). During this time, normal synchronization determination is continued to determine whether the rotational speed difference between the virtual engine speed and the virtual input shaft speed (the rotational speed of the (N + 1)th gear in the Figure 6 example shown) falls within the allowable rotational speed difference.

[0073] In Figure 6 the example shown, before the rotational speed difference between the virtual engine speed and the (N + 1)th gear speed falls within the allowable speed difference, the shift time reaches the standby time. Therefore, forced synchronization determination is performed at time t5 when the shift time reaches the standby time. Since the forced synchronization determination is performed, the virtual clutch operation amount starts to change from the disengagement operation amount to the engagement operation amount, and the virtual engine speed quickly converges to the (N + 1)th gear speed. At time t6 when the change of the virtual clutch operation amount from the disengagement operation amount to the engagement operation amount is completed, the virtual engine speed is completely synchronized with the (N + 1)th gear speed.

[0074] As described above, in the battery electric vehicle 100 according to the present embodiment, during the shift control triggered by the driver's operation of the pseudo-shifter 24, standby shift processing is performed. Therefore, the shift operation of the manual transmission internal combustion engine vehicle simulated by the battery electric vehicle 100 will always be completed within a predetermined time from the operation of the pseudo-shifter 24. Therefore, the battery electric vehicle 100 according to the present embodiment reduces the possibility that the driver may feel uncomfortable due to a long shift time.

Claims

1. A battery electric vehicle, comprising an electric motor as a driving source, wherein the battery electric vehicle is characterized by comprising: accelerator pedal; a pseudo shifter that mimics a shifter used to perform a shift operation of a manual transmission internal combustion engine vehicle; as well as a controller configured to change a relationship among a vehicle speed of the battery electric vehicle, an accelerator operation amount of the accelerator pedal, and a torque of the electric motor in response to an operation of the pseudo shifter, wherein The controller is configured to change the relationship within a predetermined time after operating the pseudo shifter.

2. The battery electric vehicle according to claim 1, characterized in that: The controller comprises: a memory storing a vehicle model for modeling a virtual vehicle, and a processing circuit coupled to the memory and configured to execute the vehicle model; The vehicle model includes: A driver model that models a typical driver, an engine model for modeling a virtual internal combustion engine, a clutch model to model a virtual clutch, and a transmission model to model a virtual manual transmission; the driver model being configured to calculate a virtual accelerator operation amount of the virtual internal combustion engine, a virtual clutch operation amount of the virtual clutch, and a virtual gear position of the virtual manual transmission based on an accelerator operation amount of the accelerator pedal, a shift position of the pseudo shifter, a vehicle speed of the battery electric vehicle, and a virtual engine speed of the virtual internal combustion engine; The engine model is configured as follows: When the virtual clutch is in an engaged state, calculating the virtual engine speed based on the virtual gear position and the vehicle speed; and When the virtual clutch is in a disengaged state, calculating the virtual engine speed based on the virtual accelerator operation amount and a virtual moment of inertia of the virtual internal combustion engine; and The driver model is configured to: After starting the shift of the virtual manual transmission, when the speed difference between the virtual engine speed and the virtual input shaft speed of the virtual manual transmission falls within a predetermined range, calculating the virtual clutch operation amount so as to engage the virtual clutch; and When the time elapsed from the start of shifting of the virtual manual transmission exceeds a predetermined standby time, the virtual clutch operation amount is calculated so as to engage the virtual clutch regardless of the speed difference between the virtual engine speed and the virtual input shaft speed.

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