Electric vehicle control device

Abstract

To provide a control device for an electric vehicle capable of simulating an engine stall and restraining the simulation of an engine stall from causing an inconvenience.SOLUTION: Provided is a controller apparatus for electric vehicle that includes a virtual engine rotation speed calculation unit configured to calculate a virtual rotation speed of an engine on the basis of operation amounts of an accelerator operation unit and clutch operation unit device, the control apparatus including the following steps of: performing engine stall control for stopping a rotating machine to simulate the engine stall when the virtual rotation speed of the engine calculated by a virtual engine rotation speed calculation unit is less than a predetermined rotation speed; and performing hold assist control for applying braking torque to wheels by braking devices when the engine stall control is executed (Step S2).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for reproducing the behavior of a vehicle equipped with an engine and a manual transmission in an electric vehicle using an electric motor as a driving force source. [Background technology]

[0002] Patent Document 1 describes a control device configured to simulate the behavior of an electric vehicle equipped with a manual transmission that sets gears between the engine and the drive wheels in response to a driver's shift operation, using a rotary machine as a driving force source connected to the drive wheels via a gear mechanism or a propeller shaft. The electric vehicle includes an accelerator pedal, a shift lever, and a clutch pedal as operational request input devices operated by the driver. The control device is configured to determine the output torque of the rotary machine in response to the amount of operation of these operational request input devices. Specifically, the control device calculates the output torque of a virtual engine in response to the amount of accelerator operation, and multiplies the output torque of the virtual engine by a gain corresponding to the amount of clutch pedal operation to determine the output torque of the rotary machine. The control device is also configured to calculate the rotation speed of the virtual engine in addition to the output torque of the rotary machine. [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 control device described in Patent Document 1 is configured to simulate the behavior of a vehicle equipped with an engine and a manual transmission using an electric vehicle that does not have an engine or a manual transmission. Therefore, for example, an engine stall can be simulated when the accelerator pedal is operated lightly and the clutch pedal is depressed less. Simulating such an engine stall can result in the torque of the rotating machine, which is the driving force source, becoming zero. For example, when simulating an engine stall on an uphill road, if the driver depresses the clutch pedal, the vehicle may unintentionally roll back, which may be undesirable. On the other hand, if an engine stall is not simulated to prevent such inconvenience, a driver who prefers vehicle operability may feel uncomfortable.

[0005] The present invention has been made in light of the above technical problems. The behavior of the vehicle can be made to match or approximate the behavior of a virtual vehicle. The present invention aims to provide a control device for an electric vehicle that can [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a control device for an electric vehicle which includes a rotary machine that transmits torque to wheels and a braking device that applies braking torque to the wheels, and which does not include an engine, a transmission connected to the engine, or a clutch mechanism that connects and disconnects torque from the engine to the wheels, but in which the rotary machine and the wheels are always connected, the control device comprising: an accelerator operation unit that is operated by a driver and determines a drive request amount of the electric vehicle; a shift operation unit that is operated by the driver and simulates operation of the transmission; and a clutch operation unit that is operated by the driver and simulates operation of the clutch mechanism. a brake operating unit that is operated by the driver and determines the braking torque of the braking device;and a controller for controlling the braking device, the controller including a virtual engine rotation speed calculation unit that calculates a virtual rotation speed of the engine based on operation amounts of the accelerator operation unit and the clutch operation unit, and performing engine stall control to stop rotation and torque output of the rotary machine when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit becomes less than a predetermined first predetermined rotation speed. and when the engine stall control is executed, a recovery notification is given to recover the engine from stall, and the recovery notification includes an operation of the brake operation unit to increase the braking torque by the braking device and an operation of the clutch operation unit to simulate the release of the clutch mechanism. It is characterized by the following.

[0010] In the present invention, the controller may stop the engine stall control when the brake operating unit and the clutch operating unit are operated. 。 Further, in the present invention, there is provided a control device for an electric vehicle which is equipped with a rotary machine that transmits torque to wheels and a braking device that applies braking torque to the wheels, and which is not equipped with an engine, a transmission connected to the engine, or a clutch mechanism that connects and disconnects torque from the engine to the wheels, but in which the rotary machine and the wheels are always connected, the control device comprising an accelerator operation unit that is operated by a driver and determines a drive request amount of the electric vehicle, a shift operation unit that is operated by the driver and simulates operation of the transmission, a clutch operation unit that is operated by the driver and simulates operation of the clutch mechanism, and a clutch operation unit that is operated by the driver and simulates operation of the brake mechanism. a brake operation unit that determines a braking torque of a rotating machine, and a controller that controls the braking unit, wherein the controller has a virtual engine rotation speed calculation unit that calculates a virtual rotation speed of the engine based on the operation amounts of the accelerator operation unit and the clutch operation unit, and when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit becomes less than a predetermined first predetermined rotation speed, the controller executes engine stall control to stop the rotation and torque output of the rotating machine, and when the brake operation unit and the clutch operation unit are operated, the controller stops the engine stall control.

[0015] In the present invention, when the engine stall control has been executed, the controller may execute a start assist control that suppresses the engine stall control from being executed again. 。 Further, in the present invention, there is provided a control device for an electric vehicle which includes a rotary machine that transmits torque to wheels and a braking device that applies braking torque to the wheels, and which does not include an engine, a transmission connected to the engine, or a clutch mechanism that connects and disconnects torque from the engine to the wheels, but in which the rotary machine and the wheels are always connected, the control device comprising an accelerator operation unit that is operated by a driver and determines a drive request amount of the electric vehicle, a shift operation unit that is operated by the driver and simulates operation of the transmission, a clutch operation unit that is operated by the driver and simulates operation of the clutch mechanism, and a brake operation unit that is operated by the driver and simulates operation of the braking mechanism. and a controller for controlling the device, the controller having a virtual engine rotation speed calculation unit that calculates a virtual rotation speed of the engine based on the operation amounts of the accelerator operation unit and the clutch operation unit, and when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit becomes less than a predetermined first predetermined rotation speed, the controller executes engine stall control that stops the rotation and torque output of the rotating machine, and when the engine stall control has been executed, executes start assist control that prevents the engine stall control from being executed again.

[0016] In the present invention, the start assist control may include control for prohibiting execution of the engine stall control by setting a lower limit value of the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit to the first predetermined rotation speed or higher. 。 In the present invention, the controller may be configured to determine the output torque of the rotating machine based on the amount of operation of the accelerator operation unit, and when the engine stall control is executed, may prohibit the rotating machine from outputting torque based on the amount of operation of the accelerator operation unit. Book In the invention, when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit is less than a predetermined second specified rotation speed that is higher than the first rotation speed, the controller may output torque from the rotating machine that causes the electric vehicle to vibrate in a longitudinal direction. [Effects of the Invention]

[0017] According to the present invention, a virtual rotation speed of an engine not provided in an electric vehicle is calculated based on the operation amount of an accelerator operation unit and a clutch operation unit. Then, when the calculated virtual rotation speed of the engine falls below a predetermined rotation speed, engine stall control is executed to simulate an engine stall. In other words, the rotating machine is stopped. Therefore, This allows the behavior of the vehicle to be simulated to be faithfully reproduced. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram schematically illustrating the configuration of an electric vehicle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the configuration of an ECU in functional blocks. [Figure 3] 4 is a flowchart illustrating an example of control executed by a control device according to an embodiment of the present invention. [Figure 4] 10 is a flowchart illustrating an example of control for determining whether or not to execute assist control depending on the driving technique of a driver. [Figure 5] 10 is a flowchart illustrating an example of control for reproducing the behavior of a vehicle immediately before an engine stall. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described based on the embodiments shown in the drawings. Note that the embodiments described below are merely examples of specific embodiments of the present invention and are not intended to limit the present invention.

[0020] FIG. 1 schematically illustrates an example of an electric vehicle (hereinafter referred to as a vehicle) according to an embodiment of the present invention. The vehicle Ve is a front-drive vehicle equipped with a motor (MG) 1 as a driving force source, and travels by transmitting torque from the motor 1 to a pair of front wheels 2. Similar to motors provided in conventional electric vehicles and hybrid vehicles, the motor 1 can be configured as a so-called motor-generator, which functions not only as a motor that outputs driving torque when supplied with power from a battery (BATT) 3, but also as a generator that generates electricity when forcibly rotated by torque transmitted from an external source. Specifically, a permanent magnet synchronous motor or induction motor can be used. The motor 1 corresponds to the "rotating machine" in the embodiment of the present invention.

[0021] An output shaft 4 of the motor 1 is connected to a gear mechanism 5, which is further connected via a propeller shaft 6 to a differential gear mechanism 7, which is a final reduction gear. The output torque of the motor 1 is distributed to left and right drive shafts 8 via the differential gear mechanism 7, and a pair of front wheels (drive wheels) 2 connected to the drive shafts 8 are driven by the motor 1 to run the vehicle Ve. In other words, the vehicle Ve does not include an engine, a transmission connected to the engine, or a clutch mechanism that can interrupt the transmission of torque between the engine and the drive wheels. Furthermore, each wheel 2 is provided with a brake mechanism B that applies a braking torque to the respective wheel 2, as in conventional vehicles. The brake mechanism B corresponds to the "brake device" in this embodiment of the present invention.

[0022] Although the vehicle Ve shown in FIG. 1 is a front-drive vehicle, the electric vehicle of the present invention may be a rear-drive electric vehicle that runs by transmitting torque from the motor 1 to a pair of rear wheels 9, or may be a four-wheel drive vehicle that is provided with a transfer and runs by transmitting torque from the motor 1 to a pair of front wheels 2 and a pair of rear wheels 9.

[0023] An inverter (INV) 10 is provided for controlling the magnitude of the current flowing through the motor 1 and the frequency of the current flowing through each phase, and a power storage device (BATT) 3 that outputs a direct current is connected to the inverter 10. In addition to the inverter 10, other electrical equipment such as a converter for amplifying the voltage output from the power storage device 3 may be provided, and the power storage device 3 may include a power storage member such as a capacitor in addition to a secondary battery such as a lithium ion battery.

[0024] An electronic control unit (hereinafter referred to as ECU) 11 is provided for controlling the switching elements of the inverter 10 and the brake mechanism B. This ECU 11 corresponds to the "controller" in the embodiment of the present invention, and is configured to be mainly composed of a microcomputer like a conventionally known ECU provided in a vehicle, and is configured to receive signals from various sensors, perform calculations based on the input signals, pre-stored calculation formulas or maps, and output the results of the calculations as control signals to various devices such as actuators (not shown) that control the inverter 10 and the brake mechanism B, or speakers (not shown).

[0025] The vehicle Ve shown in FIG. 1 includes an accelerator pedal 12 that a driver (not shown) operates to accelerate or decelerate (increase or decrease power output), i.e., determines the required drive force of the vehicle Ve, and an accelerator position sensor 13 that detects the amount of depression of the accelerator pedal. The vehicle also includes a brake pedal 14 that the driver depresses to decelerate or stop the vehicle and that determines the braking torque of a brake mechanism B depending on the amount of depression, and a brake sensor 15 that detects the amount of depression and the force with which the brake pedal is depressed. Furthermore, the vehicle is also provided with a vehicle speed sensor (rotational speed sensor) 16 that detects the rotational speed of a propeller shaft 6 (i.e., vehicle speed). These sensors 13, 15, and 16 are connected to an ECU 11, and their detection signals (detected data) are input to the ECU 11. The accelerator pedal 12 corresponds to the "accelerator operation unit" in the embodiment of the present invention, and the brake pedal 14 corresponds to the "brake operation unit" in the embodiment of the present invention.

[0026] Furthermore, the vehicle Ve shown in FIG. 1 is equipped with devices for simulating manual gear shifting. First, a shift mechanism 17 is provided, primarily consisting of a shift lever or paddle switches for manually selecting multiple forward and reverse gears, a neutral position, and other positions that do not actually exist. When shifting gears in a vehicle equipped with a manual transmission, torque transmission between a driving force source such as an engine and the drive wheels is temporarily interrupted to enable gear engagement and disengagement and to reduce shift shock. The clutch used for this purpose is typically engaged and disconnected (intermittent) by a clutch pedal. The vehicle Ve shown in FIG. 1 is equipped with a clutch pedal 18 as a clutch mechanism to simulate a vehicle equipped with such a manual transmission. An operating unit in place of the clutch pedal 18 may be provided on the steering wheel. The shift device 17 corresponds to the "shift operating unit" in the embodiment of the present invention, and the clutch pedal 18 corresponds to the "clutch operating unit" in the embodiment of the present invention.

[0027] Also provided are a shift position sensor 19 that detects the position (or mode) of the gear selected by the shift mechanism 17, and a clutch position sensor 20 that detects the amount of depression of the clutch pedal 18. These sensors 19 and 20 are connected to the above-mentioned ECU 11, and their respective detection signals (detected data) are input to the ECU 11.

[0028] The vehicle Ve described above is configured to be able to simulate driving and shifting behavior simulating that of a vehicle equipped with an engine, a transmission (manual transmission) connected to the engine, and a clutch mechanism (hereinafter referred to as an MT vehicle), as well as normal EV driving, in which torque control of the motor 1 is performed to drive and brake in response to the driver's driving request, which is expressed as the accelerator pedal position. The control for simulating driving and shifting behavior of the MT vehicle may be the control described in the aforementioned Patent Document 1, which will be briefly described below.

[0029] A model of the manual transmission vehicle to be simulated is set in advance and stored in ECU 11 as a numerical model. The actual accelerator opening (amount of depression) detected by accelerator position sensor 13, the shift position on shift mechanism 17 detected by shift position sensor 19, the actual depression of clutch pedal 18 detected by clutch position sensor 20, and the actual rotational speed of propeller shaft 6 detected by rotational speed sensor 16 are applied to this modeled manual transmission vehicle to determine the torque (driving torque and braking torque) that should be output by motor 1, and ECU 11 controls inverter 10 to realize that torque.

[0030] The modeled manual transmission vehicle (hereinafter referred to as the virtual vehicle) includes an internal combustion engine (engine) and a stepped transmission connected to the output side thereof. A virtual engine rotation speed, which is the rotation speed of the engine, is calculated based on the actual operating state input from the aforementioned sensors 13, 19, 20, and 16. As an example, the virtual engine rotation speed can be calculated by multiplying the rotation speed of the propeller shaft 6 detected by the rotation speed sensor 16 by the gear ratio at the shift position (gear) selected by the shift mechanism 17, and further multiplying this by a slip ratio corresponding to the depression amount of the clutch pedal 18 detected by the clutch position sensor 20. Furthermore, when the rotation speed of the propeller shaft 6 is 0 (zero), the accelerator opening detected by the accelerator position sensor 13 is 0%, and the depression amount of the clutch pedal 18 detected by the clutch position sensor 20 is equal to or greater than a predetermined amount and is depressed to the extent that the clutch mechanism of the virtual vehicle does not transmit torque, the virtual engine rotation speed can be calculated as a predetermined idling rotation speed, assuming that the virtual engine is idling. The functional means or functional block that performs such calculations is shown in Fig. 2 as a "virtual engine rotation speed calculation unit 110." The virtual engine rotation speed calculated by the virtual engine rotation speed calculation unit 110 is output to a speaker (not shown), and a sound that simulates the engine sound is emitted from the speaker.

[0031] The virtual engine assumed to be mounted on the virtual vehicle is an engine whose displacement, the relationship between rotational speed and output torque, efficiency, etc. are determined by design, so once the virtual engine rotational speed is calculated, the output torque of the virtual engine can be calculated based on that value, the accelerator position, and a map that defines the relationship between rotational speed and output torque for the virtual engine. The functional means or functional block that performs this calculation is shown in Figure 2 as a "virtual engine output torque calculation unit 111."

[0032] The clutch mechanism of the virtual vehicle is assumed to be a friction clutch whose transmission torque capacity changes continuously. Therefore, a predetermined relationship between the depression amount of the clutch pedal 18 and the transmission torque capacity is established by design. This relationship can be prepared in advance as a map and stored in the ECU 11. For example, the transmission torque capacity can be set as a gain that changes from "0" to "1." When the depression amount of the clutch pedal 18 is between "0" and a predetermined value, the gain is "1." As the depression amount of the clutch pedal 18 increases beyond this value, the gain gradually decreases (linearly or proportionally) with the depression amount. Therefore, the torque output from the virtual clutch mechanism assumed to be installed in the virtual vehicle is determined by the gain. The gain can be calculated based on the map and the actual depression amount of the clutch pedal 18 detected by the clutch position sensor 20. A functional means or functional block that performs this calculation is shown in FIG. 2 as a "torque transmission gain calculation unit 112."

[0033] The torque input to the manual transmission assumed to be installed in the virtual vehicle is the torque obtained by changing the virtual engine output torque in accordance with the above gain, i.e., the clutch output torque. Therefore, the clutch output torque can be calculated by multiplying the virtual engine output torque calculated by the virtual engine output torque calculation unit 111 by the gain calculated by the torque transmission gain calculation unit 112. A functional means or functional block that performs such calculation is shown in Figure 2 as a "clutch output torque calculation unit 113."

[0034] In order to simulate the gear ratio (speed ratio) set in the manual transmission of the virtual vehicle, the gear ratio of the manual transmission is calculated from the actual driving state of the vehicle Ve. The gear ratio is the ratio between the engine rotation speed of the virtual vehicle and the output rotation speed of the manual transmission (specifically, the rotation speed of the propeller shaft 6). The engine rotation speed of the virtual vehicle corresponds to the virtual engine rotation speed, and the output rotation speed corresponds to the rotation speed of the propeller shaft 6 detected by the rotation speed sensor 16. Therefore, the gear ratio is calculated by dividing the virtual engine rotation speed by the rotation speed of the propeller shaft 6. A functional means or functional block that performs this calculation is shown in FIG. 2 as a "gear ratio calculation unit 114."

[0035] To make the behavior of the vehicle Ve, including the behavior during gear shifting, match or approximate the behavior of the virtual vehicle, the output torque of the motor 1 is controlled, for example, so that the torque of the propeller shaft 6 matches or approximates the output torque of the manual transmission of the virtual vehicle. Therefore, it is necessary to calculate the output torque of the manual transmission of the virtual vehicle, which is performed by a functional means or functional block shown as a "transmission output torque calculation unit 115" in FIG. 2. Specifically, since the manual transmission increases or decreases the input torque according to the gear ratio and outputs it, the transmission output torque is calculated by multiplying the clutch output torque input to the manual transmission by the gear ratio. The clutch output torque reflects the gain calculated by the torque transmission gain calculation unit 112, and therefore corresponds to the transmission torque capacity associated with the engagement and disengagement of the clutch mechanism during a gear shift transition. Therefore, by controlling the inverter 10 by the ECU 11 to realize the torque calculated by the transmission output torque calculation unit 115 (torque at the propeller shaft 6), behavior simulating the behavior of the virtual vehicle during gear changes can be made to appear in the above-mentioned actual vehicle Ve.

[0036] When the above-described virtual vehicle is stopped with the clutch pedal 18 depressed, the virtual engine rotation speed is faster than the virtual output rotation speed on the output side of the clutch mechanism. Therefore, when the depression of the clutch pedal 18 is reduced when starting off, a resistance torque acts on the virtual engine from the output side of the clutch mechanism. As a result, the virtual engine generates a torque greater than the resistance torque, and a driving torque is transmitted from the virtual engine via the clutch mechanism. In this case, if the torque generated by the virtual engine is greater than the resistance torque, the virtual engine rotation speed increases due to the excess virtual engine torque, and if it is smaller than the resistance torque, the virtual engine rotation speed decreases due to the excess resistance torque.

[0037] Therefore, when starting, the virtual engine rotation speed calculation unit 110 calculates the torque difference between the output torque of the virtual engine calculated by the virtual engine output torque calculation unit 111 and the resistance torque calculated based on the depression amount of the clutch pedal 18 and the current virtual engine rotation speed, and calculates the rate of change of the virtual engine rotation speed from the torque difference and a predetermined moment of inertia of the virtual engine, thereby changing (updating) the virtual engine rotation speed.

[0038] When the virtual engine speed falls below a predetermined speed, engine stall control is executed to simulate an engine stall. Specifically, to simulate a state in which the engine has stalled, the engine sound from the speaker is stopped and the output of torque corresponding to the depression amount of the accelerator pedal 12 is prohibited. In other words, the accelerator request is rejected.

[0039] On the other hand, for example, when engine stall control is executed on an uphill road, if an engine stall is simulated and an accelerator request is rejected as described above, there is a possibility that the vehicle Ve will roll back when the driver depresses the clutch pedal 18 to start the vehicle again. ,ECU11 is The control system is configured to suppress the movement of the vehicle Ve when engine stall control is executed. An example of this control is shown in FIG.

[0040] In the example shown in Fig. 3, first, it is determined whether or not engine stall control has been executed (step S1). This step S1 can be determined based on whether or not the virtual engine rotation speed calculated by virtual engine rotation speed calculation unit 110, as described above, is less than a predetermined first predetermined rotation speed, such as a rotation speed at which autonomous rotation is possible, or whether or not the virtual engine rotation speed is 0 (zero) and a flag for rejecting an accelerator request is turned on. Note that the above-mentioned first predetermined rotation speed corresponds to the "predetermined rotation speed" in the embodiment of the present invention.

[0041] If the answer to step S1 is negative because engine stall control is not being executed, the routine is immediately terminated. Conversely, if the answer to step S1 is positive because engine stall control has been executed, hold assist control is executed to fix the vehicle position (step S2). This hold assist control can be implemented by adapting a conventional hill hold control or the like. That is, even if the driver is not braking, braking torque is applied by the brake mechanism B provided on each wheel 2, 9. Also, in step S2, for example, the motor 1 may be energized to output torque so as to generate a load that counteracts the longitudinal load acting on the vehicle Ve, regardless of the amount of accelerator operation by the driver.

[0042] Next, a notification (return notification) for performing an operation to return from engine stall control is output (step S3). Specifically, the notification outputs a sequence of steps: depressing the brake pedal 14 to increase the braking torque of the brake mechanism B, depressing the clutch pedal 18 to simulate the release of the clutch mechanism, selecting the first forward gear (start gear) with the shift mechanism 17, and performing a restart operation. This step S3 may be performed by outputting a signal from the ECU 11 to a speaker to provide an audio return notification, or by outputting a signal to an instrument panel (not shown) to provide a display on the instrument panel. The restart operation is an operation of reducing the depression amount of the depressed clutch pedal 18 and increasing the depression amount of the accelerator pedal 12, which is the same as a start operation for a normal manual transmission vehicle. In this control example, the virtual engine is started by depressing the brake pedal 14 and the clutch pedal 18. That is, the rotational speed of the virtual engine is set to an idle rotational speed, and sound and vibration corresponding to the idle rotational speed are generated. Furthermore, the rejection of the accelerator request is released when the first forward gear is selected by the shift mechanism 17. Note that the rejection of the accelerator request may be released on the condition that the brake pedal 14 and the clutch pedal 18 are depressed. In other words, the engine stall control ends when at least the brake pedal 14 and the clutch pedal 18 are depressed.

[0043] Next, it is determined whether restarting is possible (step S4). That is, it is determined whether the driver has performed the brake pedal 14, clutch pedal 18, shift mechanism 17, and restarting operation notified in step S3. This step S4 can be determined based on the detection signals of the accelerator position sensor 13, brake sensor 15, clutch position sensor 20, and shift position sensor 19.

[0044] If the operation based on the return notification in step S3 has not been performed and restarting is not possible, and a negative determination is made in step S4, the process returns to step S3. That is, the return notification is continued until a state in which restarting is possible is reached. Conversely, if the restarting is possible and a positive determination is made in step S4, the hold assist control executed in step S2 is stopped (step S5), and this routine is temporarily terminated.

[0045] In the above-described control example, the return notification includes the shift operation and the restart operation, but this return notification need not include the shift operation or the restart operation as long as it at least enables the vehicle to return from the engine stall control. In this case, the determination in step S4 as to whether restart is possible can be made by determining whether the brake operation and the clutch operation are being performed. In other words, the hold assist control may be stopped before the shift operation and the restart operation are performed.

[0046] As described above, when engine stall control that simulates an engine stall is executed, hold assist control is executed to fix the position of the vehicle Ve, in other words, braking torque is applied to the wheels, thereby preventing the vehicle Ve from unintentionally rolling backward when, for example, the clutch pedal 18 is depressed to restart. Furthermore, by executing hold assist control in this manner, it is not necessary to prohibit the reproduction of an engine stall, and the behavior of the virtual vehicle can be faithfully reproduced.

[0047] In the control example described above, the hold assist control is always executed when engine stall control is executed, but some drivers may feel that such hold assist control is excessive. Therefore, in the control example shown in Fig. 4, whether or not to execute the hold assist control is determined depending on the driving technique of the driver, or whether or not to execute the hold assist control is determined depending on the surrounding conditions of the vehicle Ve. Note that the same steps as in Fig. 3 are assigned the same reference numerals, and their description will be omitted.

[0048] 4, if the result of step S1 is negative due to the execution of engine stall control, it is determined whether the driver's driving skill is low (step S10). This step S10 may be determined, for example, by having the driver operate a touch panel to select a driving skill level when getting into the vehicle Ve and storing the selected level in the ECU 11, or by storing the driver's driving operations in the ECU 11 and making a determination based on the driving operation history.

[0049] If the answer to step S10 is affirmative because the driver's driving skill is poor, the process proceeds to step S2. That is, hold assist control is executed. Conversely, if the answer to step S10 is negative because the driver's driving skill is not poor, the process determines whether the vehicle is on a slope (step S11). This step S11 is a step for determining whether the situation is favorable for executing hold assist control, and the slope in step S11 includes a downhill road and an uphill road. Whether the vehicle is on a slope may be determined based on an acceleration sensor mounted on the vehicle Ve, or based on road information stored in the navigation system.

[0050] If the answer to step S11 is affirmative because the vehicle is on a slope, the process proceeds to step S2, where the hold assist control is executed. Conversely, if the answer to step S11 is negative because the vehicle is not on a slope, the process proceeds to step S3, where the hold assist control is not executed.

[0051] In the above example, whether to perform the hold assist control is determined based on whether the driver's driving skill is low, and if the driver's driving skill is not low, whether to perform the hold assist control is determined based on whether the road is on a slope. However, whether to perform the hold assist control may be determined by dividing the driver's driving skill into three levels. Specifically, if the driver's driving skill is low, the hold assist control may be performed regardless of whether the road is on a slope. If the driver's driving skill is at an intermediate level of the three levels, the hold assist control may be performed only on a slope. If the driver's driving skill is high, the hold assist control may not be performed regardless of whether the road is on a slope. Alternatively, if the driving skill is high, the system may detect, using an on-board camera or the like, whether there is another vehicle in a direction in which the vehicle Ve may move unintentionally, i.e., behind if on an uphill road or ahead if on a downhill road, and perform the hold assist control only if there is another vehicle.

[0052] In the example shown in FIG. 4, following step S3, start assist control is performed again to prevent engine stall control from being executed (step S12), and the process proceeds to step S4. This start assist control sets the lower limit of the virtual engine rotation speed to a rotation speed equal to or higher than the virtual engine rotation speed at which the virtual engine can rotate autonomously, i.e., a rotation speed equal to or higher than a first predetermined rotation speed at which engine stall control is executed, thereby prohibiting the simulation of an engine stall. As with the hold assist control, whether or not to perform start assist control may be determined depending on the driver's driving skill. Specifically, for example, if the driver's driving skill is low, start assist control may be performed regardless of whether the vehicle is on a slope; if the driver's driving skill is intermediate among three levels, start assist control may be performed only on a slope; and if the driver's driving skill is high, start assist control may not be performed regardless of whether the vehicle is on a slope, or start assist control may be performed only if there is another vehicle in the direction of movement of the vehicle Ve.

[0053] By determining whether to perform the hold assist control or the start assist control in accordance with the driver's driving skill in this way, it is possible to prevent a driver with advanced driving skill from feeling that the assist control is excessive, and it is possible to reproduce the vehicle behavior that the driver prefers.

[0054] The control device of the present invention may be configured to reproduce the behavior immediately before the engine stalls. Figure 5 shows a flowchart for explaining such a control example, and the same steps as those in Figures 3 and 4 are assigned the same reference numerals.

[0055] 5, if the negative determination is made in step S1 because engine stall control is not being executed, it is determined whether or not the state is immediately before engine stall control is to be executed (step S20). Specifically, it is determined whether or not the virtual engine rotation speed calculated by virtual engine rotation speed calculation unit 110 has become less than a predetermined second predetermined rotation speed such as an idle rotation speed. In other words, if the engine rotation speed is equal to or greater than the first predetermined rotation speed and less than the second predetermined rotation speed, the positive determination is made in step S20.

[0056] If the engine rotation speed is equal to or greater than the second predetermined rotation speed and is not in a state immediately before the execution of engine stall control, and therefore a negative determination is made in step S20, the routine is temporarily terminated. Conversely, if the engine rotation speed is less than the second predetermined rotation speed and is in a state immediately before the execution of engine stall control, and therefore a positive determination is made in step S20, the behavior of the manual transmission vehicle immediately before the engine stall is reproduced (step S21), and then the routine is temporarily terminated. That is, in step S21, the behavior of the manual transmission vehicle immediately before the engine stall is simulated to make the driver aware of the possibility of the execution of engine stall control. By making the driver aware of the possibility of the execution of engine stall control in this way, the driver is prompted to perform an operation such as depressing the accelerator pedal 12 or the clutch pedal 18, thereby avoiding the execution of engine stall control. The behavior reproduction in step S21 may, for example, change the engine sound emitted from the speaker into the vehicle cabin as the virtual engine rotation speed decreases, or output a stepped torque from the motor 1 to generate longitudinal vibrations.

[0057] As in the control example described above, when there is a possibility that engine stall control will be executed, the behavior of the manual transmission vehicle immediately before the engine stall can be reproduced to make the driver aware of the possibility that engine stall control will be executed. By making the driver aware of the signs that engine stall control will be executed in this way, the driver can be prompted to perform an operation such as depressing the accelerator pedal 12 or the clutch pedal 18, thereby preventing the engine stall control from being executed.

[0058] The present invention is not limited to the above-described embodiment, and the rotating machine in the present invention is preferably a so-called motor-generator with the above-described power generation function, but may also be configured to include a motor that outputs drive torque and a generator that generates electricity during regenerative braking. Furthermore, the rotational speed for calculating the gear stage (gear ratio) is not limited to the rotational speed of the propeller shaft described above, and may be the rotational speed of an appropriate rotating member that corresponds to the vehicle speed. [Explanation of symbols]

[0059] 1 motor 2,9 wheels 11 Electronic Control Unit (ECU) 12 Accelerator pedal 14 Brake pedal 17 Shift mechanism 18 Clutch pedal 110 Virtual engine rotation speed calculation unit 111 Virtual engine output torque calculation unit 112 Torque transmission gain calculation unit 113 Clutch output torque calculation unit 114 Gear ratio calculation unit 115 Transmission output torque calculation section B Brake mechanism Ve electric vehicle

Claims

1. A control device for an electric vehicle that includes a rotary machine that transmits torque to wheels and a braking device that applies braking torque to the wheels, and that does not include an engine, a transmission connected to the engine, or a clutch mechanism that connects and disconnects torque from the engine to the wheels, and in which the rotary machine and the wheels are always connected, an accelerator operation unit that is operated by a driver and determines a required driving amount of the electric vehicle; a shift operation unit operated by the driver to simulate operation of the transmission; a clutch operating unit operated by the driver to simulate operation of the clutch mechanism; a brake operation unit that is operated by the driver and determines a braking torque of the braking device; a controller for controlling the braking device; Equipped with The controller a virtual engine rotation speed calculation unit that calculates a virtual rotation speed of the engine based on operation amounts of the accelerator operation unit and the clutch operation unit, executing engine stall control to stop rotation and torque output of the rotary machine when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit becomes less than a predetermined first predetermined rotation speed; When the engine stall control is executed, a recovery notification is given to recover from the stall of the engine; The return notification includes an operation of the brake operating unit to increase the braking torque of the braking device, and an operation of the clutch operating unit to simulate the release of the clutch mechanism. A control device for an electric vehicle.

2. 2. The electric vehicle control device according to claim 1, The controller When the brake operating unit and the clutch operating unit are operated, the engine stall control is stopped. A control device for an electric vehicle.

3. A control device for an electric vehicle that includes a rotating machine that transmits torque to wheels and a braking device that applies braking torque to the wheels, and that does not include an engine, a transmission connected to the engine, or a clutch mechanism that interrupts the transmission of torque from the engine to the wheels, and in which the rotating machine and the wheels are always connected, an accelerator operation unit that is operated by a driver and determines a required driving amount of the electric vehicle; a shift operation unit operated by the driver to simulate operation of the transmission; a clutch operating unit operated by the driver to simulate operation of the clutch mechanism; a brake operation unit that is operated by the driver and determines a braking torque of the braking device; a controller for controlling the braking device; Equipped with The controller a virtual engine rotation speed calculation unit that calculates a virtual rotation speed of the engine based on operation amounts of the accelerator operation unit and the clutch operation unit, executing engine stall control to stop rotation and torque output of the rotary machine when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit becomes less than a predetermined first predetermined rotation speed; When the brake operating unit and the clutch operating unit are operated, the engine stall control is stopped. A control device for an electric vehicle.

4. 4. The electric vehicle control device according to claim 1, The controller When the engine stall control is executed, a start assist control is executed to prevent the engine stall control from being executed again. A control device for an electric vehicle.

5. A control device for an electric vehicle that includes a rotating machine that transmits torque to wheels and a braking device that applies braking torque to the wheels, and that does not include an engine, a transmission connected to the engine, or a clutch mechanism that interrupts the transmission of torque from the engine to the wheels, and in which the rotating machine and the wheels are always connected, an accelerator operation unit that is operated by a driver and determines a required driving amount of the electric vehicle; a shift operation unit operated by the driver to simulate operation of the transmission; a clutch operating unit operated by the driver to simulate operation of the clutch mechanism; a controller for controlling the braking device; Equipped with The controller a virtual engine rotation speed calculation unit that calculates a virtual rotation speed of the engine based on operation amounts of the accelerator operation unit and the clutch operation unit, executing engine stall control to stop rotation and torque output of the rotary machine when the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit becomes less than a predetermined first predetermined rotation speed; When the engine stall control is executed, a start assist control is executed to prevent the engine stall control from being executed again. A control device for an electric vehicle.

6. 6. The electric vehicle control device according to claim 4 or 5, The start assist control includes control for prohibiting execution of the engine stall control by setting a lower limit value of the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit to the first predetermined rotation speed or higher. A control device for an electric vehicle.

7. A control device for an electric vehicle according to any one of claims 1 to 6, The controller an output torque of the rotary machine is determined based on an operation amount of the accelerator operation unit, When the engine stall control is executed, the rotary machine is prohibited from outputting torque based on the operation amount of the accelerator operation unit. A control device for an electric vehicle.

8. A control device for an electric vehicle according to any one of claims 1 to 7, The controller When the virtual rotation speed of the engine calculated by the virtual engine rotation speed calculation unit is less than a predetermined second rotation speed that is higher than the first rotation speed, a torque that causes the electric vehicle to vibrate in a longitudinal direction is output from the rotary machine. A control device for an electric vehicle.

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