Electric vehicle

Abstract

To enable driving torque to be controlled by a driver's own operation with delicacy according to a situation, in an electric vehicle including an electric motor as a driving source.SOLUTION: A vehicle 100 includes a pseudo clutch pedal 54 imitating a clutch pedal, in addition to an accelerator pedal 52 used for driving the same. A control device 101 of the vehicle 100 controls driving torque output by an electric motor 6 in response to operation of each of the accelerator pedal 52 and the pseudo clutch pedal 54 by a driver. The control device 101 determines basic torque as driving torque in a state where the pseudo clutch pedal 54 is not operated, according to an operation amount of the accelerator pedal 52 and a vehicle speed, and changes the driving torque between the basic torque and minimum torque, according to an operation amount of the pseudo clutch pedal 54. When a predetermined condition is satisfied, the control device 101 reduces sensitivity of the change of the driving torque to the operation of the pseudo clutch pedal 54.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electric vehicle having an electric motor as a drive source. [Background technology]

[0002] Japanese Patent No. 6787507 and Japanese Patent Laid-Open No. 2022-042730 disclose prior art electric vehicles that can simulate the manual shifting operation of a manually variable-speed internal combustion engine vehicle powered by an internal combustion engine by controlling an electric motor. These prior art electric vehicles are equipped with a pseudo clutch pedal that simulates the clutch pedal of a manually variable-speed internal combustion engine vehicle, in addition to an accelerator pedal. By operating the pseudo clutch pedal with the left foot while operating the accelerator pedal with the right foot, the driver can achieve delicate control of the drive torque that is not possible with a normal electric vehicle equipped only with an accelerator pedal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6787507 [Patent Document 2] Japanese Patent Publication No. 2022-042730 Summary of the Invention [Problem to be solved by the invention]

[0004] When controlling the drive torque through the driver's own operation, it would be more preferable if the sensitivity of the control could be varied depending on the situation. One object of the present disclosure is to enable the driver to control the drive torque with sensitivity according to the situation through the driver's own operation in an electric vehicle having an electric motor as a drive source. [Means for solving the problem]

[0005] The present disclosure provides an electric vehicle to achieve the above-mentioned object. According to one aspect of the present disclosure, the electric vehicle has an electric motor as a drive source, and includes a control device that controls the drive torque output by the electric motor and two indicators that issue instructions to the control device. A first of the two indicators issues continuous instructions to the control device in accordance with an operation amount. A second of the two indicators issues continuous instructions to the control device in accordance with an operation amount that can be operated simultaneously with the first indicator. The control device is configured to determine a base torque, which is the drive torque when the second indicator is not operated, in accordance with an operation amount of the first indicator and the vehicle speed of the electric vehicle, and to change the drive torque between the base torque and the minimum torque in accordance with an operation amount of the second indicator. Furthermore, the control device is configured to reduce the sensitivity of changes in the drive torque to operation of the second indicator when a predetermined condition is met.

[0006] According to another aspect of the present disclosure, the electric vehicle may further include a third indicator that issues discrete instructions to the control device for each operation. The control device may be configured to switch the relationship between the operation amount of the first indicator, the vehicle speed, and the base torque from among a plurality of predetermined relationships in response to the operation of the third indicator.

[0007] According to yet another aspect of the present disclosure, the electric vehicle may further include a sound generator that artificially generates sound within the vehicle cabin. The sound generator may be configured to increase the sound pressure or frequency of the sound depending on the amount of operation of the second indicator, and to reduce sensitivity of the sound pressure or frequency to changes in the sound pressure or frequency in response to the operation of the second indicator when the predetermined condition is satisfied. [Effects of the Invention]

[0008] According to the electric vehicle of the present disclosure, the driver can control the drive torque delicately by operating the first indicator and the second indicator simultaneously. When a predetermined condition is met, the sensitivity of the drive torque to the operation of the second indicator is reduced, allowing the drive torque to be controlled delicately according to the situation. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a configuration of a vehicle according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of a vehicle model according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a diagram illustrating an example of a change characteristic of a virtual torque transfer capacity relative to a clutch pedal depression amount set in a clutch model according to an embodiment of the present disclosure. [Figure 4] FIG. 10 is a diagram illustrating another example of the change characteristic of the virtual transmission torque capacity with respect to the clutch pedal depression amount set in the clutch model according to the embodiment of the present disclosure. [Figure 5] FIG. 10 is a diagram illustrating another example of the change characteristic of the virtual transmission torque capacity with respect to the clutch pedal depression amount set in the clutch model according to the embodiment of the present disclosure. [Figure 6] FIG. 10 is a diagram illustrating an effect obtained by drive torque control using a clutch model according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1. Vehicle power system configuration 1 is a diagram schematically illustrating the configuration of a vehicle 100 according to an embodiment of the present disclosure. First, the configuration of the power system of the vehicle 100 will be described with reference to FIG.

[0011] The vehicle 100 is equipped with an electric motor (M) 6 as a driving source for traveling. The vehicle 100 also has a battery (BATT) 2 and an inverter (INV) 4. The battery 2 stores electric energy for driving the electric motor 6. In other words, the vehicle 100 is a battery electric vehicle (BEV) that runs on the electric energy stored in the battery 2. The electric motor 6 is, for example, a three-phase AC motor. The inverter 4 is, for example, a voltage-type inverter, and controls the torque of the electric motor 6 by PWM control.

[0012] The output shaft of the electric motor 6 is connected to a reduction gear (RG) 8. The reduction gear 8 is connected to a differential gear 14 by a propeller shaft 12. The differential gear 14 is connected to left and right drive wheels 18 by left and right drive shafts 16. The drive wheels 18 may be rear wheels or front wheels. However, the vehicle 100 may be configured as an all-wheel drive vehicle. In that case, a center differential gear may be provided on the propeller shaft 12, and the drive torque divided by the center differential gear may be transmitted to the front wheels and the rear wheels, respectively.

[0013] 2. Vehicle control system configuration Next, the configuration of the control system of the vehicle 100 will be described with reference to FIG.

[0014] The vehicle 100 is equipped with a vehicle speed sensor 40. The vehicle speed sensor 40 is a sensor that outputs a signal corresponding to the traveling speed (hereinafter referred to as vehicle speed) of the vehicle 100. At least one of wheel speed sensors (not shown) provided on each of the left and right front wheels and the left and right rear wheels is used as the vehicle speed sensor 40.

[0015] Vehicle 100 also includes accelerator position sensor 42. Accelerator position sensor 42 is provided on accelerator pedal 52 and outputs a signal corresponding to the amount of operation of accelerator pedal 52. The amount of operation of accelerator pedal 52 refers to the amount of depression of accelerator pedal 52 by the driver, i.e., the accelerator opening.

[0016] The accelerator pedal 52 is a driving operation member used to drive the vehicle 100. In addition to the accelerator pedal 52, the driving operation members also include a brake pedal (not shown). In addition to these driving operation members, the vehicle 100 is equipped with pseudo gearshift operation members that imitate operation members used to change gears in a manually variable transmission internal combustion engine vehicle. The pseudo gearshift operation members include a pseudo clutch pedal 54 and a pseudo H-type shifter 56, which will be described below.

[0017] The pseudo clutch pedal 54 is a dummy that is different from an actual clutch pedal. The pseudo clutch pedal 54 has a structure similar to that of a clutch pedal provided in a conventional manual transmission internal combustion engine vehicle. For example, the pseudo clutch pedal 54 is equipped with a reaction force mechanism that generates a reaction force when the driver presses down on the pedal. The position when no pressure is applied to the pseudo clutch pedal 54 is the start position of the pseudo clutch pedal 54, and the position when the pseudo clutch pedal is pressed down to the farthest point is the end position of the pseudo clutch pedal 54. The driver can operate the pseudo clutch pedal 54 from the start position to the end position against the reaction force from the reaction force mechanism.

[0018] Vehicle 100 is equipped with clutch position sensor 44. Clutch position sensor 44 is provided on pseudo clutch pedal 54 and is a sensor that outputs a signal according to the amount of operation of pseudo clutch pedal 54. The amount of operation of pseudo clutch pedal 54 means the amount of depression of pseudo clutch pedal 54 by the driver.

[0019] The pseudo H-shaped shifter 56 is a dummy that is different from an actual shifter. The pseudo H-shaped shifter 56 has a structure that resembles an H-shaped shifter equipped in a conventional manual transmission internal combustion engine vehicle. The pseudo H-shaped shifter 56 has a shift lever that can be moved along an H-shaped gate. Each gate is assigned a shift position. However, since the vehicle 100 does not have an actual transmission, the shift positions of the pseudo H-shaped shifter 56 are virtual shift positions. In the example shown in FIG. 1 , first, second, third, fourth, fifth, and sixth gears are provided as virtual shift positions. In a conventional manual transmission internal combustion engine vehicle, first gear is the shift position with the largest gear ratio, and the gear ratios decrease in the order of second, third, fourth, fifth, and sixth gears.

[0020] The vehicle 100 is equipped with a shift position sensor 46. The shift position sensor 46 is provided on the pseudo-H-type shifter 56 and is a sensor that outputs a signal indicating the shift position selected by the pseudo-H-type shifter 56. When the shift lever is not in any shift position, the shift position sensor 46 outputs a signal indicating the neutral position.

[0021] The vehicle 100 is equipped with a control device 101. Sensors and devices to be controlled mounted on the vehicle 100 are connected to the control device 101 via an in-vehicle network. The vehicle speed sensor 40, the accelerator position sensor 42, the clutch position sensor 44, and the shift position sensor 46 are examples of sensors mounted on the vehicle 100.

[0022] The control device 101 is typically an electronic control unit (ECU). The control device 101 may be a combination of multiple ECUs. The control device 101 includes an interface, memory, and processor (not shown). An in-vehicle network is connected to the interface. The memory includes a RAM for temporarily recording data and a ROM for storing programs executable by the processor and various data related to the programs. The programs are made up of multiple instructions. The processor reads and executes the programs and data from the memory, and generates control signals based on signals acquired from each sensor. The control device 101 may include one or more processors. The one or more processors form a processing circuit.

[0023] The control device 101 includes a driving torque control device 110 and a display and sound control device 120. In more detail, a program stored in a memory is executed by the processor, causing the processor to function as at least the driving torque control device 110 and the display and sound control device 120. The processor functioning as the driving torque control device 110 and the processor functioning as the display and sound control device 120 may be separate processors or may be the same processor.

[0024] 3. Drive torque control The control target of the driving torque control device 110 is the inverter 4. The virtual shift position of the pseudo shifter 50 obtained from the signal of the shift position sensor 46 is input to the driving torque control device 110. The driving torque control device 110 executes process P111 based on the virtual shift position. In process P111, a virtual gear ratio of the vehicle 100 is calculated using a vehicle model (described below) that models a manually variable transmission internal combustion engine vehicle. The virtual gear ratio is a gear ratio of the transmission that is virtually realized by torque control of the electric motor 6 using the vehicle model.

[0025] Further, the depression amount of the pseudo clutch pedal 54 (hereinafter referred to as clutch pedal depression amount) obtained from the signal of the clutch position sensor 44 is input to the driving torque control device 110. The driving torque control device 110 executes process P112 based on the clutch pedal depression amount. In process P112, a virtual transmission torque capacity is calculated using a vehicle model.

[0026] The driving torque control device 110 also receives as input the vehicle speed obtained from the signal of the vehicle speed sensor 40 and the accelerator opening degree obtained from the signal of the accelerator position sensor 42. The driving torque control device 110 executes step P113 based on the vehicle speed, accelerator opening degree, the virtual gear ratio calculated in step P111, and the virtual transmission torque capacity calculated in step P112. In step P113, a vehicle model is used to calculate the driving torque to be generated in the electric motor 6 from the vehicle speed, accelerator opening degree, virtual gear ratio, and virtual transmission torque capacity. The driving torque control device 110 controls the inverter 4 so that the electric motor 6 generates the driving torque obtained from the vehicle model.

[0027] Here, the vehicle model used by the driving torque control device 110 will be described with reference to FIG. 2. As shown in FIG. 2, the vehicle model MOD01 is composed of a transmission model MOD11, an engine model MOD12, and a clutch model MOD13. The transmission virtually realized by the vehicle model MOD01 is called a virtual transmission. The transmission model MOD11 models the virtual transmission. The engine virtually realized by the vehicle model MOD01 is called a virtual engine. The engine model MOD12 models the virtual engine. The clutch virtually realized by the vehicle model MOD01 is called a virtual clutch. The clutch model MOD13 models the virtual clutch.

[0028] The transmission model MOD11 calculates a virtual gear ratio. The virtual gear ratio is a gear ratio in the virtual transmission determined by the virtual shift position. A virtual gear ratio is set for each virtual shift position. The largest virtual gear ratio is set for first gear, and the virtual gear ratios decrease in the order of second, third, fourth, fifth, and sixth gears. The transmission model MOD11 calculates a virtual transmission torque using the virtual gear ratio and a virtual engine torque (described below). The virtual transmission torque is a virtual torque output from the virtual transmission. The drive torque control device 110 controls the inverter 4 so that the drive torque output by the electric motor 6 changes according to the virtual transmission torque. The virtual transmission torque changes discontinuously as the virtual gear ratio is switched. This discontinuous change in the virtual transmission torque generates a torque shock in the vehicle 100, creating the feeling that the vehicle is equipped with a stepped transmission.

[0029] The engine model MOD12 calculates a virtual engine speed and a virtual engine torque. The virtual engine speed is calculated from the vehicle speed and the virtual gear ratio according to a predetermined formula. When the virtual clutch is partially engaged, the virtual engine speed is calculated from the vehicle speed, the virtual gear ratio, and the virtual slip ratio. The virtual engine torque is calculated from the virtual engine speed and the accelerator position. The engine model MOD12 defines a relationship between the virtual engine speed and the virtual engine torque for each accelerator position. The torque characteristics of the engine model MOD12 can be set to characteristics assumed for a gasoline engine or a diesel engine. Furthermore, the torque characteristics can be set to characteristics assumed for a naturally aspirated engine or a supercharged engine. When the virtual engine speed drops below a predetermined engine stall speed, the virtual engine torque fluctuates for a very short time and then becomes zero, and the virtual engine speed also drops to zero.

[0030] The clutch model MOD13 calculates a virtual transmission torque capacity. The virtual transmission torque capacity refers to the transmission torque capacity of the virtual clutch. In the clutch model MOD13, the virtual transmission torque capacity is assigned to the clutch pedal depression amount. The clutch pedal depression amount is 0% at the start position of the pseudo clutch pedal 54 and 100% at the end position of the pseudo clutch pedal 54. When the clutch pedal depression amount is 100%, the virtual transmission torque capacity is zero. At this time, the virtual clutch in the clutch model MOD13 is completely disengaged, and the transmission of virtual engine torque from the virtual engine to the virtual transmission is cut off. When the clutch pedal depression amount is reduced from 100%, the state of the virtual clutch changes from a disengaged state to a partially engaged state. This causes the virtual transmission torque capacity to begin to increase, and accordingly, the transmission of virtual engine torque from the virtual engine to the virtual transmission begins. When the virtual transmission torque capacity becomes equal to or greater than the virtual engine torque, the virtual clutch is engaged, and all of the virtual engine torque output from the virtual engine is input to the virtual transmission. The virtual slip ratio may be calculated based on the virtual torque transmission capacity, or may be given in relation to the clutch pedal depression amount in a map.

[0031] 4. Details of the clutch model In an actual clutch installed in a manually variable-speed internal combustion engine vehicle, the transmission torque capacity is mechanically determined by factors such as spring force, disc diameter, number of discs, and friction coefficient. The clutch stroke is also mechanically determined by the distance between the discs. Therefore, in an actual clutch, the change in transmission torque capacity relative to changes in clutch stroke is also mechanically determined, and this change is essentially constant except for aging due to use.

[0032] On the other hand, with the virtual clutch realized by the above-described clutch model MOD13, the change characteristics of the virtual transmission torque capacity can be made variable by programming the clutch model MOD13. One advantage of using the clutch model MOD13 to calculate the drive torque is that the driver can precisely control the drive torque output from the electric motor 6 by operating the pseudo clutch pedal 54 with his / her left foot while operating the accelerator pedal 52 with his / her right foot. If the change characteristics of the virtual transmission torque capacity relative to the clutch pedal depression amount can be made variable depending on the situation, it becomes possible to control the drive torque with precision according to the situation.

[0033] 3 is a diagram showing an example of the change characteristic of the virtual transmission torque capacity with respect to the clutch pedal depression amount (hereinafter referred to as the virtual transmission torque capacity characteristic) set in the clutch model MOD13. In this example, the basic characteristic C0 and the low-sensitivity characteristic C1 are set in the clutch model MOD13 as the virtual transmission torque capacity characteristic.

[0034] The basic characteristic C0 and the low-sensitivity characteristic C1 differ in the size of the range of clutch pedal depression amount in which the virtual clutch is in a half-engaged state. With the low-sensitivity characteristic C1, when the clutch pedal depression amount is returned from 100%, the virtual clutch changes from a released state to a half-engaged state at a clutch pedal depression amount greater than that of the basic characteristic C0. In other words, the starting point of the half-engaged state in the low-sensitivity characteristic C1 is closer to the end position of the pseudo clutch pedal 54 than the starting point of the half-engaged state in the basic characteristic C0. Therefore, the range of clutch pedal depression amount in which the virtual clutch is in a half-engaged state is larger with the low-sensitivity characteristic C1 than with the basic characteristic C0. When the virtual clutch is in a half-engaged state, the change in virtual transmission torque capacity with respect to the change in clutch pedal depression amount is lower with the low-sensitivity characteristic C1 than with the basic characteristic C0.

[0035] The torque output from the clutch model MOD13 is obtained by multiplying the torque output by the clutch model MOD13 by the virtual gear ratio calculated by the transmission model MOD11 and a predetermined virtual reduction ratio. When the accelerator opening is constant, i.e., when the virtual engine torque is constant, the torque output from the clutch model MOD13 is determined by the virtual transmission torque capacity characteristics of the clutch model MOD13 and the clutch pedal depression amount. Therefore, when the low-sensitivity characteristic C1 is selected in the clutch model MOD13, the ratio of the change in driving torque to the change in clutch pedal depression amount is smaller than when the basic characteristic C0 is selected. In other words, when the low-sensitivity characteristic C1 is selected, the sensitivity of the change in driving torque to the operation of the pseudo clutch pedal 54 is smaller than when the basic characteristic C0 is selected.

[0036] If the sensitivity of the drive torque change to the operation of the pseudo clutch pedal 54 is reduced, it becomes possible to control the drive torque more precisely by operating the pseudo clutch pedal 54. However, on the other hand, the virtual clutch is in a half-engaged state for a longer period of time, which causes a delay in acceleration in response to the operation of the accelerator pedal 52. Therefore, in the clutch model MOD13, the basic characteristic C0 is normally selected, and the low-sensitivity characteristic C1 is selected only when a predetermined condition is met.

[0037] To determine whether the conditions for selecting the low-sensitivity characteristic C1 are met, the clutch model MOD13 receives information such as the vehicle speed, the operating speed of the pseudo clutch pedal 54, the shift position of the pseudo H-type shifter 56, and the virtual engine torque calculated by the engine model MOD12. The conditions for selecting the low-sensitivity characteristic C1 include at least the following three conditions: If none of the three conditions are met, the basic characteristic C0 is selected, and if any one of the conditions is met, the low-sensitivity characteristic C1 is selected.

[0038] The first condition for selecting the low-sensitivity characteristic C1 is that the vehicle speed is lower than a predetermined speed. The predetermined speed is set, for example, between 0 km / h and 20 km / h. When starting or traveling at low speeds in a manual-speed internal combustion engine vehicle, suddenly engaging the clutch causes the engine speed to drop suddenly, resulting in an engine stall. Since the engine model MOD12 also reproduces an engine stall in the virtual engine, depending on the driver's operation of the pseudo clutch pedal 54, the driving force of the electric motor 6 may be suddenly lost, causing the vehicle 100 to stop. Therefore, by selecting the low-sensitivity characteristic C1 when the vehicle speed is lower than the predetermined speed, it is possible to reduce the likelihood of an engine stall occurring, even for a driver who is not adept at operating the pseudo clutch pedal 54.

[0039] A second condition for selecting the low-sensitivity characteristic C1 is that the operation speed of the pseudo clutch pedal 54 is lower than a predetermined speed. A low operation speed of the pseudo clutch pedal 54 can be considered to mean that the driver is carefully operating the pseudo clutch pedal 54 so as to maintain the virtual clutch in a partially engaged state. Selecting the low-sensitivity characteristic C1 in such a case makes it easier to control the virtual transmission torque capacity of the virtual clutch through operation of the pseudo clutch pedal 54, and enables delicate control of the drive torque output from the electric motor 6.

[0040] The third condition for selecting the low-sensitivity characteristic C1 is that a shift position with a predetermined high gear ratio is selected in the pseudo H-type shifter 56. The predetermined high-speed ratio shift position is, for example, first or second gear. In a manual-speed internal combustion engine vehicle, the higher the gear ratio selected in the transmission, the more likely it is that changes in vehicle acceleration will occur due to changes in the clutch's transmission torque capacity. This is a common issue with the vehicle 100, which is a reproduction of a manual-speed internal combustion engine vehicle using the vehicle model MOD01. However, while the sensitivity of a manual-speed internal combustion engine vehicle to changes in transmission torque capacity in response to clutch pedal operation is fixed, the sensitivity of the vehicle 100 can be changed between the basic characteristic C0 and the low-sensitivity characteristic C1. By selecting the low-sensitivity characteristic C1 when a shift position with a high gear ratio is selected, changes in vehicle acceleration due to operation of the pseudo clutch pedal 54 can be suppressed.

[0041] In addition to the low sensitivity characteristic C1, multiple low sensitivity characteristics with different sensitivities may be set in the clutch model MOD13. In this case, the lower the virtual speed ratio of the selected shift position, the lower the low sensitivity characteristic that may be selected.

[0042] If all three of the above conditions are not met, the virtual transmission torque capacity characteristic of the clutch model MOD13 is switched from the low-sensitivity characteristic C1 to the basic characteristic C0. However, even if any of the above three conditions is met, the virtual transmission torque capacity characteristic is switched from the low-sensitivity characteristic C1 to the basic characteristic C0 if the following condition is met: the driver depresses the accelerator pedal 52 while the virtual clutch is partially engaged, increasing the virtual engine torque. If the virtual transmission torque capacity is insufficient for the increased virtual engine torque, the virtual clutch slips, increasing the virtual engine speed, but torque is not transmitted to the virtual transmission, resulting in an insufficient driving torque output by the electric motor 6. Therefore, if the above condition is met when the low-sensitivity characteristic C1 is selected, the virtual transmission torque capacity characteristic can be switched from the low-sensitivity characteristic C1 to the basic characteristic C0 to prevent a lack of driving torque in response to the driver's operation of the accelerator pedal 52.

[0043] The above is an explanation of one example of the virtual transmission torque capacity characteristic set in the clutch model MOD13. As explained above, the virtual transmission torque capacity characteristic is variable, and it is sufficient if it includes, in addition to the basic characteristic, a characteristic that can reduce the sensitivity of changes in drive torque to the operation of the pseudo clutch pedal 54. Figure 4 is a diagram showing another example of the virtual transmission torque capacity characteristic set in the clutch model MOD13. In this example, the basic characteristic C0 and the low-sensitivity characteristic C2 are set in the clutch model MOD13 as the virtual transmission torque capacity characteristic.

[0044] The basic characteristic C0 and the low-sensitivity characteristic C2 differ in the size of the range of clutch pedal depression amount in which the virtual clutch is in a half-engaged state. With the low-sensitivity characteristic C2, when the clutch pedal depression amount is returned from 100%, the virtual clutch changes from a half-engaged state to an engaged state at a clutch pedal depression amount that is smaller than that of the basic characteristic C0. In other words, the end point of the half-engaged state in the low-sensitivity characteristic C2 is closer to the starting position of the pseudo clutch pedal 54 than the end point of the half-engaged state in the basic characteristic C0. Therefore, the range of clutch pedal depression amount in which the virtual clutch is in a half-engaged state is larger for the low-sensitivity characteristic C2 than for the basic characteristic C0. When the virtual clutch is in a half-engaged state, the change in virtual transmission torque capacity with respect to the change in clutch pedal depression amount is smaller for the low-sensitivity characteristic C2 than for the basic characteristic C0.

[0045] The low-sensitivity characteristic C2 described above can be combined with the low-sensitivity characteristic C1 shown in Figure 3. In this case, the start point of the half-engaged state will be closer to the terminal position of pseudo clutch pedal 54 than the start point of the half-engaged state in the basic characteristic C0, and the end point of the half-engaged state will be closer to the starting position of pseudo clutch pedal 54 than the end point of the half-engaged state in the basic characteristic C0.

[0046] 5 is a diagram showing yet another example of the virtual transmission torque capacity characteristic set in the clutch model MOD13. In this example, the basic characteristic C0 and the low-sensitivity characteristic C3 are set in the clutch model MOD13 as the virtual transmission torque capacity characteristic.

[0047] The maximum virtual transmission clutch capacity of the virtual clutch differs between the basic characteristic C0 and the low-sensitivity characteristic C3. The maximum virtual transmission clutch capacity of the low-sensitivity characteristic C3 is set lower than the maximum virtual transmission clutch capacity of the basic characteristic C0. Therefore, when the virtual clutch is in a partially engaged state, the amount of change in virtual transmission torque capacity relative to the amount of clutch pedal depression is lower for the low-sensitivity characteristic C3 than for the basic characteristic C0.

[0048] The low-sensitivity characteristic C3 may be combined with the low-sensitivity characteristic C1 shown in Figure 3 to set the maximum virtual transmission clutch capacity at the low-sensitivity characteristic C1 lower than that at the basic characteristic C0. Also, the low-sensitivity characteristic C3 may be combined with the low-sensitivity characteristic C2 shown in Figure 4 to set the maximum virtual transmission clutch capacity at the low-sensitivity characteristic C2 lower than that at the basic characteristic C0.

[0049] 5.Effects Fig. 6 is a diagram for explaining the effect obtained by driving torque control using the clutch model MOD 13. Fig. 6 shows the change in driving torque when the pseudo clutch pedal 54 is operated with the accelerator opening angle held constant.

[0050] Here, the drive torque when the pseudo clutch pedal 54 is not operated, i.e., when the clutch pedal depression amount is 0%, is referred to as the base torque. The base torque varies depending on the accelerator opening, vehicle speed, and the shift position of the pseudo H-type shifter 56. As the pseudo clutch pedal 54 is operated and the clutch pedal depression amount increases, the drive torque decreases from the base torque. Then, when the pseudo clutch pedal 54 is depressed to approximately 100%, the drive torque decreases to the minimum torque. In the example shown in Figure 6, the minimum torque is set to 0 Nm. Then, as the depressed pseudo clutch pedal 54 is returned to its original, undepressed state, the drive torque begins to increase from the minimum torque and eventually reaches the base torque.

[0051] The driving torque varies from minimum torque to basic torque depending on the amount of clutch pedal depression. When the basic characteristic is selected as the virtual transmission torque capacity characteristic of the clutch model MOD13, the driving torque varies as shown by the dashed line in Figure 6. On the other hand, when the above-mentioned predetermined conditions are met, the low-sensitivity characteristic is selected as the virtual transmission torque capacity characteristic, and the driving torque varies as shown by the solid line in Figure 6.

[0052] As is clear from a comparison of the change in drive torque shown by the dashed line with the change in drive torque shown in actual driving, when the above-mentioned predetermined conditions are met, the sensitivity of the change in drive torque to the operation of pseudo clutch pedal 54 is made smaller than usual. This allows the driver of vehicle 100 to control the drive torque with sensitivity appropriate to the situation.

[0053] 6. Display and sound control Returning to Fig. 1 again, the display and sound control by the display and sound control device 120 will be described. The display and sound control is a control that gives the driver the visual and auditory sensation of driving a manual transmission internal combustion locomotive. The display and sound control includes display control that gives the driver the visual sensation of driving a manual transmission internal combustion locomotive, and sound control that gives the driver the auditory sensation of driving a manual transmission internal combustion locomotive.

[0054] The display and sound control device 120 receives as input the vehicle speed obtained from the signal of the vehicle speed sensor 40 and the accelerator opening degree obtained from the signal of the accelerator position sensor 42. Furthermore, the display and sound control device 120 receives as input the virtual gear ratio calculated in process P111 and the virtual transmission torque capacity calculated in process P112 from the driving torque control device 110. The display and sound control device 120 executes process P121 based on the input information. In process P121, the operating point of the virtual engine, which is represented by the virtual engine speed and virtual engine torque, is calculated. A vehicle model MOD01 is used to calculate the operating point of the virtual engine.

[0055] The control target of the display control is an instrument panel 30 provided on the instrument panel of the vehicle 100. The instrument panel 30 includes a pseudo engine speed meter, a pseudo engine torque meter, and a pseudo engine power meter. These meters may be analog meters or digital meters. The instrument panel 30 does not have to be a dedicated device. For example, the instrument panel 30 may be displayed on the display by switching the display mode.

[0056] The pseudo engine speed meter displays the virtual engine speed calculated in process P121. The pseudo engine torque meter displays the virtual engine torque. And the pseudo engine power meter displays the virtual engine power calculated from the virtual engine speed and virtual engine torque. The displays of these meters change depending on the driver's operation of the accelerator pedal 52, and also change depending on the operation of the pseudo clutch pedal 54 and the pseudo H-type shifter 56. By watching the meter displays change in this way, the driver can visually get the feeling that he or she is driving a manually-shifted internal combustion engine vehicle.

[0057] The control target of the sound control is the sound generator 32. Sound artificially generated by the sound generator 32 is output from a speaker installed in the cabin of the vehicle 100. The sound generator 32 can generate a variety of sounds. One of the artificial sounds is a pseudo engine sound that imitates the engine sound of a conventional engine vehicle. The sound generator 32 changes the sound pressure and frequency of the pseudo engine sound generated from the speaker.

[0058] The display and sound control device 120 executes process P122 based on the operating point of the virtual engine calculated in process P121. In process P122, the sound pressure of the pseudo engine sound is calculated using the sound pressure map, and the frequency of the pseudo engine sound is calculated using the frequency map. In the sound pressure map, sound pressure data is set relative to the virtual engine speed so that the sound pressure increases as the virtual engine speed increases. Also, sound pressure data is set relative to the virtual engine torque so that the sound pressure increases as the virtual engine torque increases. In the frequency map, frequency data is set relative to the virtual engine speed so that the frequency increases as the virtual engine speed increases. Therefore, the sound pressure and frequency of the pseudo engine sound emitted from the speaker change depending on the driver's operation of the accelerator pedal 52, and also change depending on the operation of the pseudo clutch pedal 54 and the pseudo H-type shifter 56. By listening to the pseudo engine sound whose sound pressure and frequency change in this way, the driver auditorily acquires the sensation of driving a manually-shifted internal combustion engine vehicle.

[0059] 7. Variations In the above-described embodiment, accelerator pedal 52 and accelerator position sensor 42 constitute a first indicator that issues continuous instructions to control device 101 in accordance with the amount of operation of accelerator pedal 52. Accelerator pedal 52 is a pedal-type operating tool operated by foot, but a lever-type operating tool operated by hand may also be used as the first indicator.

[0060] In the above-described embodiment, the pseudo clutch pedal 54 and the clutch position sensor 44 constitute a second indicator that can be operated simultaneously with the pseudo clutch pedal 54 and that issues continuous instructions to the control device 101 according to the amount of operation of the pseudo clutch pedal 54. The pseudo clutch pedal 54 is a pedal-type operating device operated by a foot, but a lever-type operating device or a dial-type operating device operated by a hand may also be used as the second indicator. However, the second indicator is required to be operable with a foot or hand different from the foot or hand that operates the first indicator.

[0061] In the above-described embodiment, the pseudo-H-type shifter 56 and the shift position sensor 46 constitute a third indicator that issues a discrete instruction to the control device 101 for each operation of the pseudo-H-type shifter 56. The pseudo-H-type shifter 56 is a shifter in which each operation is uniquely associated with a shift position, but a relative instruction type shifter such as a sequential shifter may also be used as the third indicator. The sequential shifter may have a structure similar to a shift stick provided on a console, or a structure similar to shift paddles attached to a steering wheel, for example.

[0062] The drive torque control technology of the present disclosure is not limited to battery electric vehicles (BEVs) but can be widely applied to any electric vehicle that uses an electric motor as a driving power unit. For example, the drive torque control technology of the present disclosure can be applied to hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) that have a mode in which they run solely on the driving force of the electric motor. The drive torque control technology of the present disclosure can also be applied to fuel cell electric vehicles (FCEVs) that supply electric energy generated by a fuel cell to the electric motor. [Explanation of symbols]

[0063] 2 battery, 4 inverter, 6 electric motor, 8 reduction gear, 12 propeller shaft, 14 differential gear, 16 drive shaft, 18 drive wheel, 30 instrument panel, 32 sound generator, 40 vehicle speed sensor, 42 accelerator position sensor, 44 clutch position sensor, 46 shift position sensor, 52 accelerator pedal, 54 pseudo clutch pedal, 56 pseudo H-type shifter, 100 vehicle, 101 control device, 110 drive torque control device, 120 display and sound control device

Claims

1. An electric vehicle having an electric motor as a drive source, a control device for controlling a driving torque output by the electric motor; a first indicator that outputs continuous instructions to the control device in accordance with an operation amount; a second indicator that can be operated simultaneously with the first indicator and that issues successive instructions to the control device in accordance with an operation amount; The control device determining a base torque, which is the drive torque when the second indicator is not operated, in accordance with an operation amount of the first indicator and a vehicle speed of the electric vehicle; changing the drive torque between the basic torque and the minimum torque in accordance with an operation amount of the second indicator; and reducing the sensitivity of the change in the driving torque to the operation of the second indicator when a predetermined condition is satisfied. An electric vehicle characterized by:

2. 2. The electric vehicle according to claim 1, a third indicator that issues a discrete instruction to the control device for each operation; The control device is configured to switch the relationship between the operation amount of the first indicator, the vehicle speed, and the base torque from among a plurality of predetermined relationships in response to the operation of the third indicator. An electric vehicle characterized by:

3. 3. The electric vehicle according to claim 1, The predetermined condition includes the vehicle speed being lower than a predetermined speed. An electric vehicle characterized by:

4. 3. The electric vehicle according to claim 1, The predetermined condition includes that the operation speed of the second indicator is lower than a predetermined speed. An electric vehicle characterized by:

5. 3. The electric vehicle according to claim 2, The predetermined condition includes that the third indicator is operated so as to increase the basic torque when the operation amount of the first indicator is the same and the vehicle speed is the same. An electric vehicle characterized by:

6. 3. The electric vehicle according to claim 1, The control device is configured to increase the sensitivity when the operation amount of the first indicator increases while the sensitivity is reduced. An electric vehicle characterized by:

7. 2. The electric vehicle according to claim 1, Further provided with a sound generator that artificially generates sound in the vehicle interior, The sound generator comprises: increasing the sound pressure or frequency of the sound in accordance with the amount of operation of the second indicator; When the predetermined condition is satisfied, the sensitivity of the sound pressure or frequency change to the operation of the second indicator is reduced. An electric vehicle characterized by:

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