Electric vehicle

Abstract

To provide an electric vehicle having an electric motor as a driving source, which can perform operation of speed-change that is equivalent to operation of speed-change in a vehicle loaded with a manual transmission-type internal combustion engine, in a wide area from an area where large driving force is required to a high-speed area.SOLUTION: A vehicle according to an embodiment in the disclosure is an electric vehicle using an electric motor as a driving source. The vehicle is provided with a transmission having a plurality of transmission gear ratios that can be switched and a pseudo shifter that can select shift positions that are more than the number of transmission gear ratios that can be switched by the transmission. A control device of the vehicle determines a combination of motor torque of the electric motor and the transmission gear ratios of the transmission so that a relation between accelerator opening, vehicle speed and torque of a driving wheel is switched in accordance with the shift position selected by the pseudo shifter.SELECTED DRAWING: Figure 3

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 discloses a conventional electric vehicle that can simulate the manual shifting operation of a manually variable internal combustion engine vehicle driven by an internal combustion engine by controlling an electric motor. The electric vehicle according to the conventional technology is equipped with a pseudo shift lever, and causes the electric motor to output torque according to the shift position of the pseudo shift lever and the accelerator opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6787507 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described conventional technology allows a driver to experience the operation of a manual-transmission internal combustion engine vehicle in an electric vehicle. However, because the manual transmission operated in the above-described conventional technology is merely virtual, the driving force of the electric vehicle can only be changed within a driving force range determined by the maximum torque of the electric motor and the reduction ratio from the electric motor to the drive wheels. Therefore, depending on the maximum torque of the electric motor, there is a concern that the driving force may be insufficient when a large driving force is required. Furthermore, while simply increasing the reduction ratio would solve the insufficient driving force, doing so could make high-speed driving difficult due to the constraints on the motor rotation speed. In other words, the above-described conventional technology does not necessarily allow a driver to enjoy the same level of gear-shifting experience as a manual-transmission internal combustion engine vehicle over a wide range, from areas requiring large driving force to high-speed areas.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and one objective of the present disclosure is to enable an electric vehicle having an electric motor as a drive source to enjoy gear shifting operations equivalent to those of a manually-shifted internal combustion engine vehicle over a wide range of speeds, from those requiring large driving force to high speeds. [Means for solving the problem]

[0006] The present disclosure provides an electric vehicle that achieves the above-mentioned objective. According to one aspect of the disclosure, the electric vehicle includes a transmission with multiple switchable gear ratios, a pseudo shifter that can select a number of shift positions greater than the number of switchable gear ratios of the transmission, and a control device that controls an electric motor serving as a drive source and the transmission. The control device is configured to determine a combination of motor torque of the electric motor and gear ratio of the transmission so that the relationship between accelerator opening, vehicle speed, and drive wheel torque changes depending on the shift position selected by the pseudo shifter. [Effects of the Invention]

[0007] According to the electric vehicle of the present disclosure, by combining an electric motor with a transmission, it is possible to drive in a wide range of ranges, from ranges requiring large driving force to high speeds. Furthermore, by determining the combination of the motor torque of the electric motor and the gear ratio of the transmission according to the shift position of the pseudo shifter, the driver can enjoy pseudo gear changes with a number of gear ratios greater than the number of gear ratios that the transmission has. [Brief explanation of the drawings]

[0008] [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. 4 is a diagram showing a first example of a motor torque map for determining a motor torque based on a gear position of a transmission. [Figure 4] FIG. 10 is a diagram showing a second example of a motor torque map for determining a motor torque based on a gear position of a transmission. [Figure 5] FIG. 10 is a diagram showing a third example of a motor torque map for determining a motor torque based on a gear position of a transmission. [Figure 6] FIG. 4 is a diagram showing an example of a motor torque map when the transmission has three speeds. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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.

[0010] 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.

[0011] The output shaft of the electric motor 6 is connected to a transmission (T / M) 8. The transmission 8 is a stepped transmission having switchable high-speed and low-speed gears. The high-speed gear is a gear with a relatively high speed ratio that can cover the high-speed range. The low-speed gear is a gear with a relatively low speed ratio that can cover the range where a large driving force is required. The switching between the high-speed and low-speed gears of the transmission 8 is performed by a control device 101, which will be described later.

[0012] The transmission 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 either 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 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 shifter 56 is a dummy that differs from an actual shifter. The pseudo shifter 56 has a structure resembling an H-shaped shifter equipped in a conventional manual-transmission internal combustion engine vehicle. The pseudo shifter 56 has a shift lever as a shift operation member, which can be moved along an H-shaped gate. Each gate is assigned a shift position. However, because the vehicle 100 does not have an actual transmission, the shift positions of the pseudo shifter 56 are virtual shift positions. One feature of the vehicle 100 according to an embodiment of the present disclosure is that the number of shift positions selectable by the pseudo shifter 56 is greater than the number of gears in the transmission 8. 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, followed by second, third, fourth, fifth, and sixth gears, in that order.

[0020] The vehicle 100 is equipped with a shift position sensor 46. The shift position sensor 46 is provided in the pseudo shifter 56 and outputs a signal indicating the shift position selected by the pseudo 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 wheel torque control device 110 and a sound control device 120. More specifically, a program stored in a memory is executed by a processor, causing the processor to function as at least the driving wheel torque control device 110 and the sound control device 120. The processor functioning as the driving wheel torque control device 110 and the processor functioning as the sound control device 120 may be separate processors or may be the same processor.

[0024] 3. Drive wheel torque control The control targets of the driving wheel torque control device 110 are the inverter 4 and the transmission 8. A virtual shift position of the pseudo shifter 56 obtained from a signal of the shift position sensor 46 is input to the driving wheel torque control device 110. The driving wheel 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 the gear ratio of a virtual transmission that is virtually realized in the vehicle 100 by combining torque control of the electric motor 6 using the vehicle model and gear shift control of the transmission 8.

[0025] Further, the driving wheel torque control device 110 receives 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. The driving wheel 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 wheel 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 wheel 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 motor 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 wheel torque control device 110 controls the inverter 4 so as to generate the motor torque obtained from the vehicle model.

[0027] The driving wheel torque control device 110 executes step P114 based on at least one of the vehicle speed, the accelerator opening, and the virtual gear ratio calculated in step P111. In step P114, the gear position of the transmission 8 is determined in accordance with a predetermined control rule. The driving wheel torque control device 110 controls the transmission 8 to operate at the determined gear position. The transmission 8 shifts from a high gear to a low gear, or from a low gear to a high gear, or maintains the current gear position.

[0028] Here, the vehicle model used by the driving wheel 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 virtual transmission is modeled in the transmission model MOD11. The engine virtually realized by the vehicle model MOD01 is called a virtual engine. The virtual engine is modeled in the engine model MOD12. The clutch virtually realized by the vehicle model MOD01 is called a virtual clutch. The virtual clutch is modeled in the clutch model MOD13.

[0029] The transmission model MOD11 calculates a virtual gear ratio. The virtual gear ratio is a gear ratio in the virtual transmission that is 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, which will be described later. The virtual transmission torque is a virtual torque that is output from the virtual transmission.

[0030] The driving wheel torque control device 110 calculates the motor torque based on the gear position of the transmission 8 so that the driving wheel torque generated in the driving wheels 18 changes according to the virtual transmission torque. A motor torque map, which will be described later, is used to calculate the motor torque based on the gear position. The driving wheel torque control device 110 controls the inverter 4 so that the motor torque calculated based on the gear position of the transmission 8 is output to the electric motor 6.

[0031] 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.

[0032] 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.

[0033] 4.Motor torque map details The motor torque map is a map for determining the motor torque based on the gear stage of the transmission 8, i.e., the gear ratio. A motor torque map is prepared for each gear stage of the transmission 8 and for each required value of driving wheel torque. The required value of driving wheel torque is equal to the virtual transmission torque multiplied by a predetermined reduction ratio. In this embodiment, the transmission 8 has a low-speed gear and a high-speed gear, so a map for the low-speed gear and a map for the high-speed gear are prepared for each required value of driving wheel torque.

[0034] 3 is a diagram showing a first example of a motor torque map. In the first example, the low-speed gear map and the high-speed gear map have the same size and shape of the area defined by motor torque and motor speed. In the first example, of the first to sixth shift positions selectable by the pseudo shifter 56, first to third gears are associated with low-speed gears, and the low-speed gear map defines the relationship between motor speed and motor torque for the first to third gear shift positions. Furthermore, of the first to sixth shift positions selectable by the pseudo shifter 56, fourth to sixth gears are associated with high-speed gears, and the high-speed gear map defines the relationship between motor speed and motor torque for the fourth to sixth gear shift positions.

[0035] When the transmission 8 is operated in a low gear, the driving wheel torque control device 110 selects a low gear map according to the required value of driving wheel torque and determines the motor torque based on the shift position selected by the pseudo shifter 56 and the motor speed in accordance with the selected low gear map. When the transmission 8 is operated in a high gear, the driving wheel torque control device 110 selects a high gear map according to the required value of driving wheel torque and determines the motor torque based on the shift position selected by the pseudo shifter 56 and the motor speed in accordance with the selected high gear map. The motor speed used to determine the motor torque is the required motor speed, which is calculated based on the virtual gear ratio determined by the shift position selected by the pseudo shifter 56 and the vehicle speed.

[0036] As described above, by switching the motor torque map according to the gear position of the transmission 8, the drive wheel torque-vehicle speed characteristics shown in the graph on the right of Fig. 3 are realized. As this characteristic diagram shows, combining the electric motor 6 with the transmission 8 makes it possible to drive in a wide range of speeds, from low speeds where a large driving force is required to high speeds. Furthermore, by determining the combination of the motor torque of the electric motor 6 and the gear ratio of the transmission 8 according to the shift position of the pseudo shifter 56, the driver can enjoy pseudo gear changes with a number of gear ratios that is greater than the number of gear positions that the transmission 8 has.

[0037] 4 is a diagram showing a second example of a motor torque map. In the second example, the low-speed gear map is defined over the full range, whereas the high-speed gear map is defined over a limited range on the high-speed side of the low-speed gear map. In the second example, of the first to sixth shift positions selectable by the pseudo shifter 56, first to sixth are associated with low-speed gears, and the low-speed gear map defines the relationship between motor speed and motor torque at the first to sixth shift positions. Furthermore, of the first to sixth shift positions selectable by the pseudo shifter 56, fifth and sixth are associated with high-speed gears, and the high-speed gear map defines the relationship between motor speed and motor torque at the fifth and sixth shift positions.

[0038] The relationship between motor speed and motor torque at the fifth and sixth gear positions of the pseudo shifter 56 is defined in both a low-speed gear map and a high-speed gear map. In the graph on the right of FIG. 4, the solid line represents the drive wheel torque achieved by operating the transmission 8 in a low gear and controlling the electric motor 6 according to the low-speed gear map when the fifth and sixth gear positions are selected on the pseudo shifter. On the other hand, the dashed line represents the drive wheel torque achieved by operating the transmission 8 in a high gear and controlling the electric motor 6 according to the high-speed gear map when the fifth and sixth gear positions are selected on the pseudo shifter. As can be seen from the comparison of the two maps, the low-speed gear map and the high-speed gear map are created so that the drive wheel torque is continuous with changes in vehicle speed when switching between low and high gears.

[0039] In the second example, the low-speed gear is a regular gear having a regular gear ratio, and the high-speed gear is a gear for high-speed driving having a high-speed gear ratio lower than the regular gear ratio. By the driving wheel torque control device 110 switching between the low-speed gear and the high-speed gear according to the vehicle speed, the driver can enjoy gear-changing operations equivalent to those of a manually-shifted internal combustion engine vehicle over a wide range from low speeds where large driving force is required to high speeds.

[0040] FIG. 5 is a diagram showing a third example of a motor torque map. In the third example, the high-speed gear map is defined over the full range, whereas the low-speed gear map is defined over a limited range on the large drive wheel torque side of the high-speed gear map. In the third example, of the first to sixth shift positions selectable by the pseudo shifter 56, first and second gears are associated with low gears, and the low-speed gear map defines the relationship between motor speed and motor torque at the first and second shift positions. Furthermore, of the first to sixth shift positions selectable by the pseudo shifter 56, second to sixth gears are associated with high gears, and the high-speed gear map defines the relationship between motor speed and motor torque at the second to sixth shift positions.

[0041] The relationship between motor speed and motor torque when the pseudo shifter 56 is in the second gear position is defined in both a low-speed gear map and a high-speed gear map. In the graph on the right of FIG. 5, the solid line represents the drive wheel torque achieved by operating the transmission 8 in a low gear and controlling the electric motor 6 according to the low-speed gear map when the pseudo shifter is in the second gear position. On the other hand, the dashed line represents the drive wheel torque achieved by operating the transmission 8 in a high gear and controlling the electric motor 6 according to the high-speed gear map when the pseudo shifter is in the second gear position. As can be seen from a comparison of the two maps, the low-speed gear map and the high-speed gear map are created so that the drive wheel torque is continuous with changes in vehicle speed when switching between low and high gears.

[0042] In a third example, the high-speed gear is a regular gear having a regular gear ratio, and the low-speed gear is a gear for large driving force having a low-speed gear ratio higher than the regular gear ratio. The driving wheel torque control device 110 switches between the low-speed gear and the high-speed gear in accordance with the required value of driving wheel torque, allowing the driver to enjoy gear-changing operations equivalent to those of a manually-shifted internal combustion engine vehicle over a wide range from low speeds where large driving force is required to high speeds.

[0043] 5. Sound Control Returning to FIG. 1 again, sound control by the sound control device 120 will be explained. Sound control is a control that gives the driver the auditory sensation of driving a manual transmission internal combustion engine vehicle. The control target of sound control is the sound generator 30. Sound artificially generated by the sound generator 30 is output from speakers installed in the passenger compartment of the vehicle 100. The sound generator 30 can generate a variety of sounds. One of these artificial sounds is a pseudo engine sound that imitates the engine sound of a conventional engine vehicle. The sound generator 30 changes the sound pressure and frequency of the pseudo engine sound generated from the speaker.

[0044] The sound control device 120 executes process P121 based on the virtual engine speed and virtual engine torque input from the drive wheel torque control device 110. 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 for the virtual engine speed so that the sound pressure increases as the virtual engine speed increases. Also, sound pressure data is set for the virtual engine torque so that the sound pressure increases as the virtual engine torque increases. In the frequency map, frequency data is set for 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 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.

[0045] 6. Variations In the above-described embodiment, the transmission 8 has two gears. However, the transmission 8 may have three or more gears. Regardless of the number of gears of the transmission 8, a map defining the relationship between the motor speed and the motor torque for each shift position of the pseudo shifter 56 may be prepared for each required value of drive wheel torque and each gear. For example, if the transmission 8 has three gears, a low-speed gear map, a medium-speed gear map, and a high-speed gear map may be prepared, as shown in FIG. 6. In the example shown in FIG. 6, the low-speed gear map defines the relationship between the motor speed and the motor torque at the first and second gear positions. The medium-speed gear map defines the relationship between the motor speed and the motor torque at the third to sixth gear positions. The high-speed gear map defines the relationship between the motor speed and the motor torque at the seventh and eighth gear positions. The transmission 8 may also be a continuously variable transmission with a step shift function.

[0046] In the above-described embodiment, the accelerator pedal 52 is a pedal-type operating device operated by foot, but it may also be a lever-type operating device operated by hand. Also, the pseudo clutch pedal 54 is a pedal-type operating device operated by foot, but it may also be a lever-type operating device or a dial-type operating device operated by hand.

[0047] In the above-described embodiment, the pseudo shifter 56 is an H-type shifter, which is an absolute instruction type shifter in which shift positions are associated with predetermined physical positions and are configured to be selected by a shift operation member. In contrast, a sequential shifter such as a paddle shifter is a relative instruction type shifter in which an increase or decrease in the instruction value of the shift position is associated with the relative movement of the shift operation member. The pseudo shifter 56 may also be a relative instruction type shifter.

[0048] 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]

[0049] 2 battery, 4 inverter, 6 electric motor, 8 transmission, 12 propeller shaft, 14 differential gear, 16 drive shaft, 18 drive wheel, 30 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 shifter, 100 vehicle, 101 control device, 110 drive wheel torque control device, 120 sound control device

Claims

1. An electric vehicle having an electric motor as a drive source, a transmission having a plurality of switchable gear ratios; a pseudo shifter that can select a number of shift positions greater than the number of gear ratios that can be switched by the transmission; a control device that controls the electric motor and the transmission, The control device is configured to determine a combination of the motor torque of the electric motor and the gear ratio of the transmission so that the relationship between the accelerator opening, the vehicle speed, and the drive wheel torque changes depending on the shift position selected by the pseudo shifter. An electric vehicle characterized by:

2. 2. The electric vehicle according to claim 1, The control device a map defining the relationship between the motor speed of the electric motor and the motor torque for each shift position of the pseudo shifter, for each required value of the drive wheel torque and each gear ratio of the transmission; and determining the motor torque based on the shift position selected by the pseudo shifter in accordance with a map corresponding to the gear ratio at which the transmission operates and the required value of the drive wheel torque. An electric vehicle characterized by:

3. 3. The electric vehicle according to claim 2, One or more shift positions selectable by the pseudo shifter are associated with each gear ratio of the transmission, The map for each gear ratio defines the relationship between the motor speed and the motor torque at one or more shift positions associated with that gear ratio. An electric vehicle characterized by:

4. 3. The electric vehicle according to claim 2, a relationship between the motor speed and the motor torque at a predetermined shift position among the shift positions selectable by the pseudo shifter is defined by both a map for a first gear ratio among the plurality of gear ratios and a map for a second gear ratio adjacent to the first gear ratio; A drive wheel torque realized by operating the transmission at the first speed ratio and controlling the electric motor according to the map for the first speed ratio when the predetermined shift position is selected by the pseudo shifter, and a drive wheel torque realized by operating the transmission at the second speed ratio and controlling the electric motor according to the map for the second speed ratio when the predetermined shift position is selected by the pseudo shifter, are continuous with respect to changes in the vehicle speed. An electric vehicle characterized by:

5. 4. The electric vehicle according to claim 1, The pseudo-shifter is an absolute-indication shifter configured to associate shift positions with predetermined physical positions and to select the physical positions with a shift operating member; and a relative instruction type shifter in which an increase or decrease in an instruction value of a shift position is associated with the relative movement of a shift operation member. An electric vehicle characterized by:

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