Electric vehicles

Abstract

To provide an electric vehicle equipped with a transmission with a reverse gear, in which an electric motor suppresses a great shock from being generated even when switching the gear stage to the reverse gear while traveling forward or switching the gear stage to a forward gear while traveling backward.SOLUTION: The electric vehicle according to the invention is configured so that when a transmission is switched to a reverse gear while the electric vehicle is traveling forward (affirmative determination in S10, and affirmative determination in S11), or when the transmission is switched to a forward gear while the electric vehicle is traveling backward (affirmative determination in S12, and affirmative determination in S14), fail-safe control is executed (S13) to allow reverse rotation of the motor generator (MG), thereby suppressing a great shock from being generated in the vehicle.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to electric vehicles. [Background technology]

[0002] Japanese Patent Application Publication No. 2014-183610 (Patent Document 1) discloses that in an electric vehicle in which the drive wheels are driven by the output of a motor, when the range position of the shift lever is in D range (forward range), the motor rotates forward to move the vehicle forward, and when the range position is in R range (reverse range), the motor rotates reversely to move the vehicle backward. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-183610 A Summary of the Invention [Problem to be solved by the invention]

[0004] The electric vehicle of Patent Document 1 does not have a transmission, but the output of the motor may be transmitted to the drive wheels via a transmission in order to extend the driving range by driving the motor in an efficient range, or to improve driving performance by increasing the drive torque of the drive wheels. Some transmissions have forward and reverse gears as gear stages. The reverse gear is used when the vehicle is moving backwards (reverse), and reverses the rotation direction of the output shaft of the transmission from the rotation direction of the forward gear. Hereinafter, a transmission with forward and reverse gears is also referred to as a transmission with reverse gear.

[0005] In an electric vehicle in which the output of a motor is transmitted to a drive wheel via a transmission with a reverse gear, it is desirable to switch the gear to the reverse gear by operating a shift lever when the vehicle is moving backwards. In such an electric vehicle, when the gear is in a forward gear, the motor rotates in the direction in which the vehicle moves forward when the gear is in a forward gear. In this disclosure, the rotation of the motor in the direction in which the vehicle moves forward when the gear is in a forward gear is referred to as "forward rotation," and the direction of rotation is referred to as "forward direction."

[0006] In this way, in an electric vehicle equipped with a transmission with a reverse gear, the motor is controlled to rotate in the forward direction, and the vehicle moves forward and backward by switching the gears of the transmission. Therefore, when the shift lever is operated to switch the gear from the forward gear to the reverse gear while the vehicle is moving forward, the drive wheels are driven in the reverse direction by the motor rotating in the forward direction, causing a large shock to the vehicle. Similarly, when the shift lever is operated to switch the gear from the reverse gear to the forward gear while the vehicle is moving backward, the drive wheels are driven in the forward direction by the motor rotating in the forward direction, causing a large shock to the vehicle.

[0007] An object of the present disclosure is to prevent a large shock from occurring to an electric vehicle equipped with a transmission with a reverse gear, even when switching to reverse gear while moving forward, or switching to forward gear while moving in reverse. [Means for solving the problem]

[0008] The electric vehicle disclosed herein is an electric vehicle that includes a motor, a transmission having a forward gear and a reverse gear and transmitting the output of the motor to drive wheels, and a control device, and when the motor rotates in the forward direction, the vehicle moves forward when the forward gear is achieved, and moves backward when the reverse gear is achieved. The control device controls the motor to rotate in the forward direction when the electric vehicle is traveling. When the electric vehicle is moving forward, the control device allows reverse rotation, in which the motor rotates in the direction opposite to the forward rotation, when the transmission is switched to the reverse gear, and when the electric vehicle is moving in reverse, the control device allows reverse rotation of the motor when the transmission is switched to the forward gear.

[0009] According to this configuration, when the electric vehicle is traveling, the motor is controlled to rotate in the forward direction, and moves forward when the forward gear of the transmission is achieved, and moves backward when the reverse gear is achieved. The forward and reverse movement of the electric vehicle is achieved by operating the gear of the transmission. When the electric vehicle is traveling forward, if the transmission is switched to the reverse gear, reverse rotation of the motor is permitted. When the electric vehicle is traveling backward, if the transmission is switched to the forward gear, reverse rotation of the motor is permitted. Reverse rotation of the motor means that the motor rotates in the direction opposite to the forward rotation.

[0010] When an electric vehicle is switched to reverse gear while moving forward, reverse rotation of the motor is permitted, so the drive wheels can be prevented from being driven in the reverse direction, and a large shock to the vehicle can be prevented.When an electric vehicle is switched to forward gear while moving backward, reverse rotation of the motor is permitted, so the drive wheels can be prevented from being driven in the forward direction, and a large shock to the vehicle can be prevented.

[0011] Preferably, the control device allows the motor to rotate in reverse until the electric vehicle comes to a stop. According to this configuration, when the electric vehicle is switched to reverse gear while moving forward, or when the electric vehicle is switched to forward gear while moving backward, the motor is allowed to rotate in reverse until the electric vehicle stops. When the electric vehicle stops, the motor is controlled to rotate forward, enabling the vehicle to travel in a manner corresponding to the gear of the transmission.

[0012] Preferably, when the control device permits reverse rotation of the motor, the control device may control the motor so that torque is output in a reverse rotation direction.

[0013] With this configuration, when the electric vehicle is switched to reverse gear while moving forward, or when the electric vehicle is switched to forward gear while moving backward, the motor outputs torque in the direction of reverse rotation, which can counteract the inertial force of the motor in the forward rotation direction, and more effectively prevents large shocks to the vehicle.

[0014] Preferably, the control device may allow the motor to rotate in reverse by setting the output torque of the motor to zero.

[0015] According to this configuration, when the electric vehicle is switched to reverse gear while moving forward, or when the electric vehicle is switched to forward gear while moving in reverse, the output torque of the motor is made zero and the motor is allowed to rotate in reverse, thereby preventing a large shock to the vehicle and enabling the vehicle to decelerate towards a stop. Effect of the Invention

[0016] According to the present disclosure, even when switching to reverse gear while moving forward, or switching to forward gear while moving backward, it is possible to prevent a large impact from occurring to the vehicle. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing an overall configuration of an electric vehicle according to an embodiment of the present invention; [Diagram 2] 2 is a diagram illustrating functional blocks configured in a control ECU in the present embodiment. FIG. [Diagram 3] 4 is a flowchart showing an example of a process executed by a control ECU in the present embodiment. [Figure 4] 4 is a flowchart showing an example of a fail-safe control process executed by a control ECU. [Diagram 5] 4 is a map for calculating the counter torque Tqr. [Figure 6] 10 is a flowchart showing an example of a fail-safe control process executed by a control ECU in the first modification. [Figure 7] 13 is a map for calculating counter torque Tqr in Modification 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description thereof will not be repeated.

[0019] 1 is a diagram showing the overall configuration of an electric vehicle according to this embodiment. The electric vehicle V includes a motor generator (MG) 1, a clutch 2, a transmission 3, a differential gear 4, and drive wheels 5.

[0020] MG1 is a rotating electric machine, for example an interior permanent magnet (IPM) synchronous motor with a permanent magnet embedded in the rotor, and corresponds to the "motor" in this disclosure. An output shaft (rotor shaft) of MG1 is connected to clutch 2. When clutch 2 is engaged, the output torque of MG1 is input to transmission 3.

[0021] The transmission 3 is a constant mesh type manual transmission, and may be, for example, a five-speed manual transmission. The transmission 3 has forward and reverse gears 3a as gear stages. When the reverse gear 3a is selected by a shift lever (not shown), the rotation direction of the output shaft of the transmission 3 becomes the opposite direction to the rotation direction in the forward gear stage.

[0022] The transmission 3 may be a multi-speed automatic transmission or a continuously variable transmission. In this case, the output torque of the MG1 is input to the transmission 3 via a torque converter instead of the clutch 2. When the transmission 3 is a planetary gear type multi-speed automatic transmission, the reverse gear 3a is achieved by controlling the engagement state of friction engagement devices (clutches, brakes). In the case of a continuously variable transmission, a forward / reverse switching device made of planetary gears or the like corresponds to the reverse gear 3a, and the reverse gear is achieved when the forward / reverse switching device is switched to reverse.

[0023] An output shaft of the transmission 3 is connected to a differential gear 4 via a propeller shaft. The differential gear 4 is connected to driving wheels 5 via a drive shaft. The electric vehicle V transmits the output torque (driving torque) output from the MG1 to the driving wheels 5 via the transmission 3 and the differential gear 4.

[0024] The power control unit (PCU) 20 is a power conversion device that converts power bidirectionally between the MG1 and the battery 10. The PCU 20 includes, for example, an inverter and a converter. The converter boosts the voltage supplied from the battery 10 and supplies the boosted voltage to the inverter. The inverter converts the DC power supplied from the converter into AC power to drive the MG1.

[0025] The battery 10 is a rechargeable secondary battery, and is an assembled battery in which a plurality of single cells (battery cells) are stacked. For example, the cells are electrically connected in series. The single cells may be lithium ion batteries or nickel metal hydride batteries. The battery 10 and the PCU 20 are connected via a system main relay (SMR) 30.

[0026] The battery 10 can be charged using an external power source 200. The electric vehicle V is equipped with an inlet 60, to which a connector 220 of the external power source 200 can be connected. The external power source 200 may be a commercial alternating current (AC) power source, and AC power supplied from the external power source 200 to the inlet 60 is converted to DC power by a charger 50 and supplied to the battery 10 via a charging relay 70, thereby charging the battery 10. When the electric vehicle V is braked, the battery 10 may be charged using regenerative power from the MG1.

[0027] The control ECU (Electronic Control Unit) 100 corresponds to the "control device" of the present disclosure, and controls the PCU 20, the SMR 30, the charger 50, the charging relay 70, and the like. The control ECU 100 includes a CPU (Central Processing Unit) 101 and a memory (including, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory)) 102. The control ECU 100 controls each device such as the PCU 20 based on information such as signals from various sensors and maps and programs stored in the memory 102, so that the electric vehicle V is in a desired state.

[0028] The various sensors input to the control ECU 100 include, for example, an accelerator opening sensor 151, a shift position sensor 152, a vehicle speed sensor 153, a wheel speed sensor 154, and a longitudinal acceleration sensor 155. The accelerator opening sensor 151 detects an accelerator opening ACCP, which is the amount of depression of the accelerator pedal. The shift position sensor 152 detects a position (shift position) P of a shift lever that operates the gear stage of the transmission 3. The vehicle speed sensor 153 detects a vehicle speed SPD of the electric vehicle V. The wheel speed sensor 154 detects a speed (wheel speed) WS of the drive wheels 5. The longitudinal acceleration sensor 155 detects a longitudinal acceleration Gx of the electric vehicle V.

[0029] The control ECU 100 performs normal control when the electric vehicle V is traveling. In normal control, the control ECU 100 calculates a target drive torque Tr based on the accelerator opening ACCP, the vehicle speed SPD, etc., and multiplies the target drive torque Tr by the wheel speed WS to obtain a target output. Then, the control ECU 100 calculates a command torque Tqt for MG1 so that the target output is output from MG1. The command torque Tqt is a torque in the direction in which the electric vehicle V moves forward (forward direction) when the gear stage of the transmission 3 is the forward gear (hereinafter also referred to as "positive torque"). The control ECU 100 controls the PCU 20 so that the output torque of MG1 becomes the command torque Tqt.

[0030] During normal control, MG1 rotates in the forward direction (forward rotation). Therefore, if MG1 rotates in the reverse direction opposite to the forward rotation during normal control, there is a high probability that the system has malfunctioned. The control ECU 100 determines the reverse rotation of MG1 using a signal from the resolver or rotary encoder of MG1. Then, when the control ECU 100 detects the reverse rotation of MG1 during normal control, it determines that the system has malfunctioned and issues an alarm. The alarm may be the illumination of a Malfunction Indicator Light (MIL).

[0031] In the electric vehicle V, forward and backward movement is switched by switching the gears (forward and reverse) of the transmission 3. For example, when the electric vehicle V is parked in reverse (back parking), in order to finely adjust the position of the parking space and the electric vehicle V, forward and backward movement is repeated. In this situation, when the gear is switched from the forward gear to the reverse gear while the electric vehicle V is moving forward, and the reverse gear is achieved as the gear, the drive wheels 5 are driven in the reverse direction by the MG1 rotating forward, and a large shock is generated for the vehicle. Also, when the gear is switched from the reverse gear to the forward gear while the electric vehicle V is moving backward, and the forward gear is achieved as the gear, the drive wheels 5 are driven in the forward direction by the MG1 rotating forward, and a large shock is generated for the vehicle.

[0032] In this embodiment, when reverse gear is achieved while moving forward, or when forward gear is achieved while moving backward, MG1 is permitted to rotate in reverse to prevent a large shock from occurring to the vehicle.

[0033] Fig. 2 is a diagram illustrating functional blocks configured in the control ECU 100 in this embodiment. In Fig. 2, a traveling direction detection unit 110 detects the traveling direction (forward, reverse) of the electric vehicle V. For example, based on a wheel speed WS detected by a wheel speed sensor 154, the rotation direction of the drive wheels 5 is detected to detect the traveling direction of the electric vehicle V. A gear determination unit 120 determines whether the gear selected by the shift lever is a forward gear or a reverse gear. For example, based on a shift position P detected by a shift position sensor 152, it determines whether the gear is a forward gear or a reverse gear.

[0034] The fail-safe control unit 130 executes "fail-safe control" that permits reverse rotation of the MG 1. When the traveling direction detected by the traveling direction detection unit 110 is forward and the gear stage determination unit 120 determines the reverse stage, the fail-safe control unit 130 executes the fail-safe control. Also, when the traveling direction detected by the traveling direction detection unit 110 is reverse and the gear stage determination unit 120 determines the forward stage, the fail-safe control unit 130 executes the fail-safe control.

[0035] 3 is a flowchart showing an example of processing executed by the control ECU 100 in this embodiment. This flowchart is repeatedly processed at predetermined intervals during startup of the electric vehicle V (from when the power switch is turned ON until the power switch is turned OFF). In step (hereinafter, step is abbreviated as "S") 10, it is determined whether the electric vehicle V is moving forward. For example, if the wheel speed WS detected by the wheel speed sensor 154 indicates that the vehicle is rotating in the forward direction, it is determined that the vehicle is moving forward (positive determination), and the process proceeds to S11. On the other hand, if it is not determined that the vehicle is moving forward (negative determination), the process proceeds to S12.

[0036] In S11, it is determined whether the gear of the transmission 3 is reverse gear. If the transmission 3 is a five-speed manual transmission, the shift position P detected by the shift position sensor 152 outputs a signal indicating the forward gears "1st gear to 5th gear" and the reverse gear "R". In S11, if the shift position P is a signal indicating "R", it is determined that the gear is reverse gear (positive determination), and the process proceeds to S13. If the shift position P is not a signal indicating "R", it is determined that the gear is not reverse gear (negative determination), and the process proceeds to S16.

[0037] In step 12, it is determined whether the electric vehicle V is moving backward. If the wheel speed WS detected by the wheel speed sensor 154 indicates that the vehicle is rotating in the backward direction, it is determined that the vehicle is moving backward (positive determination), and the process proceeds to S14. On the other hand, if it is not determined that the vehicle is moving backward (negative determination), the vehicle V is stopped, and the process proceeds to S16.

[0038] In S14, it is determined whether the gear of the transmission 3 is a forward gear. When the shift position P detected by the shift position sensor 152 is a signal indicating "1st gear to 5th gear," it is determined to be a forward gear (positive determination), and the process proceeds to S13. When the shift position P is not a signal indicating "1st gear to 5th gear," it is determined to be not a forward gear (negative determination), and the process proceeds to S16.

[0039] In S13, fail-safe control is executed. For example, flag F is set to 1, and thus the fail-safe control described below is executed. In S16, normal control is executed. For example, flag F is set to 0, and thus the normal control is executed. As described above, in normal control, command torque Tqt of MG1 is calculated based on accelerator opening ACCP, vehicle speed SPD, etc., and PCU 20 is controlled. Command torque Tqt in normal control is a positive torque.

[0040] 4 is a flowchart showing an example of a fail-safe control process executed by the control ECU 100. This flowchart is executed when the process of S13 (FIG. 3) is executed (when the flag F is set to 1).

[0041] In FIG. 4, in S20, the "failure determination" that determines that the system has a failure when reverse rotation of MG1 is detected is prohibited.

[0042] In the next step S21, the counter torque Tqr is calculated based on the absolute value |SPD| of the vehicle speed SPD. FIG. 5 is a map for calculating the counter torque Tqr. In FIG. 5, the vertical axis represents the magnitude of the counter torque Tqr, and the horizontal axis represents time. As shown in FIG. 5, the initial value of the counter torque Tqr is set to a larger value as the absolute value |SPD| of the vehicle speed SPD is higher, and decreases over time to 0. The initial value of the counter torque Tqr is set to a larger value as the absolute value |SPD| of the vehicle speed SPD is higher because the inertial force of MG1 in the forward rotation direction is larger as the vehicle speed SPD (absolute value |SPD|) is higher, and therefore a larger counter torque Tqr is used to cancel the inertial force of MG1. Note that this map is set in advance by experiments, etc.

[0043] In S21, the counter torque Tqr is calculated from the map of Fig. 5 based on the vehicle speed SPD detected by the vehicle speed sensor 153. Note that the vehicle speed SPD is the vehicle speed SPD detected by the vehicle speed sensor 153 when S21 is processed (when the flag F is set to 1 and this routine is started).

[0044] In the next S22, the PCU 20 is controlled so that the reverse torque Tqr is output from the MG 1. The reverse torque Tqr is a torque that acts in a direction opposite to the forward rotation direction, and this allows the MG 1 to rotate in the reverse direction opposite to the forward rotation.

[0045] In S23, it is determined whether or not the electric vehicle V has stopped. For example, when the wheel speed WS becomes 0, it is determined that the electric vehicle V has stopped. If the electric vehicle V has not stopped, a negative determination is made in S23, and the process proceeds to S22. In S22, the PCU 20 is controlled so that the counter torque Tqr is output from the MG1, and the counter torque Tqr decreases over time and becomes 0.

[0046] When the wheel speed WS becomes 0 and the electric vehicle V stops, a positive determination is made in S23 and the process proceeds to S24. In S24, a "failure determination" is permitted to determine that the system has a malfunction when reverse rotation of MG1 is detected, and then the current process is terminated.

[0047] According to this embodiment, when the electric vehicle V is traveling, the MG1 is controlled to rotate forward by normal control, moves forward when the forward gear of the transmission 3 is achieved, and moves backward when the reverse gear is achieved. The forward and reverse movement of the electric vehicle V is achieved by operating the gear of the transmission 3. When the electric vehicle V is traveling forward, if the transmission 3 is switched to the reverse gear, the reverse rotation of the MG1 is permitted by fail-safe control. Since the reverse rotation of the MG1 is permitted, it is possible to prevent the drive wheels 5 from being driven in the reverse direction, and it is possible to prevent the occurrence of a large shock to the vehicle. When the electric vehicle V is traveling backward, if the transmission 3 is switched to the forward gear, the reverse rotation of the MG1 is permitted by fail-safe control. Since the reverse rotation of the MG1 is permitted, it is possible to prevent the drive wheels 5 from being driven in the forward direction, and it is possible to prevent the occurrence of a large shock to the vehicle.

[0048] The reverse rotation of the MG1 is permitted until the electric vehicle V stops. When the electric vehicle V stops, the fail-safe control ends and normal control starts, so that the MG1 is controlled to rotate in the forward direction and the vehicle can travel in a speed range corresponding to the gear of the transmission 3.

[0049] In this embodiment, when the electric vehicle V is switched to the reverse gear while moving forward, or when the electric vehicle V is switched to the forward gear while moving backward, the MG1 is controlled to output a reverse torque Tqr, and the MG1 outputs torque in a direction in which the MG1 rotates in reverse. This reverse torque Tqr can cancel the inertial force of the MG1 in the forward rotation direction, and the occurrence of a large shock to the vehicle can be more suitably suppressed.

[0050] Furthermore, the counter torque Tqr becomes 0 regardless of the magnitude of the accelerator opening ACCP, as shown in the map of Fig. 5. Therefore, regardless of the operation state of the accelerator pedal, the electric vehicle V is decelerated toward a stop.

[0051] (Variation 1) In the above embodiment, reverse rotation of MG1 is permitted when the shift lever is used to switch to reverse gear while the electric vehicle V is moving forward, or when the shift lever is used to switch to forward gear while the electric vehicle V is moving backward. Even if the shift lever is used to switch to reverse gear or forward gear, the rotation (torque) of MG1 is not input to the transmission 3 while the clutch 2 is disengaged. Therefore, the reverse rotation of MG1 may be permitted taking into consideration the engagement state of the clutch 2.

[0052] Fig. 6 is a flowchart showing an example of the process of fail-safe control executed by the control ECU in Modification 1. In the flowchart of Fig. 6, the process of S25 is added before the processes of S20 to S24 in Fig. 4, and the processes of S20 to S24 are the same as the processes of S20 to S24 in Fig. 4.

[0053] In the first modified example, when the fail-safe control is started, in S25, it is determined whether or not the clutch 2 is in an engaged state. If the clutch 2 is in a released state, a negative determination is made, and S25 is processed again until the clutch 2 is in an engaged state. If the clutch 2 is in an engaged state, an affirmative determination is made in S25, and the process proceeds to S20. The process from S20 onwards is the same as that in FIG. 4, and therefore a description thereof will be omitted.

[0054] In this modification 1, the same effects as those of the above embodiment are achieved. (Variation 2) In the above embodiment, in the fail-safe control, the counter torque Tqr is calculated from the map in Fig. 5 based on the absolute value |SPD| of the vehicle speed SPD. In the second modification, the counter torque Tqr is calculated based on the absolute value |Gx| of the longitudinal acceleration Gx of the electric vehicle V.

[0055] Fig. 7 is a map for calculating the counter torque Tqr in Modification 2. In Fig. 7, the vertical axis represents the magnitude of the counter torque Tqr, and the horizontal axis represents the absolute value |Gx| of the longitudinal acceleration Gx. As shown in Fig. 7, the counter torque Tqr increases as the absolute value |Gx| of the longitudinal acceleration Gx increases, and becomes 0 when the absolute value |Gx| becomes small.

[0056] In the second modification, in the process of S21 (FIGS. 4 and 6), the counter torque Tqr is calculated using the map of FIG 7. Then, in the second modification, if a negative determination is made in S23, the process proceeds to S21, and each time S21 is processed, the absolute value |Gx| is obtained from the longitudinal acceleration Gx detected by the longitudinal acceleration sensor 155, the counter torque Tqr is calculated from the map of FIG 7, and the PCU 20 is controlled so that the counter torque Tqr is output from the MG1.

[0057] In this second modification as well, the inertial force in the forward rotation direction of MG1 can be counteracted by the counter torque Tqr calculated from the map of FIG. 7, and the occurrence of a large shock to the vehicle can be more suitably suppressed.

[0058] (Variation 3) In the above embodiment, in the fail-safe control, the counter torque Tqr is calculated from the map in Fig. 5 based on the absolute value |SPD| of the vehicle speed SPD. In the fail-safe control, the command torque of MG1 may be set to 0 without calculating the counter torque Tqr.

[0059] In the third modification, in the process of S21 (FIGS. 4 and 7), the command torque Tqt of MG1 is set to 0. As a result, in S22, the PCU 20 is controlled so that the torque output from MG1 becomes 0.

[0060] In this third modification as well, when the electric vehicle V is switched to the reverse gear while moving forward, or when the electric vehicle V is switched to the forward gear while moving backward, the reverse rotation of the MG1 is permitted, so that it is possible to prevent a large shock from being generated on the vehicle. Also, the electric vehicle V is decelerated toward a stop.

[0061] In the above embodiment, an example has been described in which the transmission 3 is a constant mesh type manual transmission. In the case where a planetary gear type multi-stage automatic transmission is used as the transmission, when the forward range (D range) is selected, it may be determined that the transmission is in the forward stage, and when the reverse range (R range) is selected, it may be determined that the transmission is in the reverse stage. In addition, in the planetary gear type multi-stage automatic transmission, when the friction engagement device of the forward stage starts to engage, it may be determined that the transmission is in the forward stage, and when the friction engagement device of the reverse stage starts to engage, it may be determined that the transmission is in the reverse stage. In the case where the transmission is a continuously variable transmission, when the forward / reverse switching device is switched to forward, it may be determined that the transmission is in the forward stage, and when the forward / reverse switching device is switched to reverse, it may be determined that the transmission is in the reverse stage.

[0062] The following are examples of embodiments of the present disclosure. 1) An electric vehicle (V) including a motor (1), a transmission (3) having a forward gear and a reverse gear for transmitting the output of the motor (1) to drive wheels (5), and a control device (100), in which, when the motor (1) rotates in the forward direction, the vehicle moves forward when the forward gear is achieved, and moves backward when the reverse gear is achieved, the control device (100) controls (S16) the motor (1) to rotate in the forward direction when the electric vehicle (V) is traveling, and when the electric vehicle (V) is moving forward, when the transmission (3) is switched to the reverse gear, the control device (100) allows reverse rotation in which the motor (1) rotates in the opposite direction to the forward rotation, and when the electric vehicle (V) is moving backward, when the transmission (3) is switched to the forward gear, the control device (100) allows reverse rotation of the motor (2) (S13).

[0063] 2) In the above 1, the control device (100) allows the motor (1) to rotate in the reverse direction until the electric vehicle (V) stops, regardless of the operation of the accelerator pedal.

[0064] 3) In the above 1 or 2, the control device (100) prohibits a failure determination that would be made upon detection of reverse rotation of the motor (1) while the reverse rotation of the motor (1) is permitted.

[0065] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0066] 1 MG, 2 clutch, 3 transmission, 3a reverse gear, 4 differential gear, 5 drive wheels, 10 battery, 20 PCU, 30 SMR, 50 charger, 60 inlet, 70 charging relay, 100 control ECU, 101 CPU, 102 memory, 110 direction detection unit, 120 gear determination unit, 130 fail-safe control unit, 151 accelerator opening sensor, 152 shift position sensor, 153 vehicle speed sensor, 154 wheel speed sensor, 155 front / rear acceleration sensor, 200 external power supply, 220 connector, V electric vehicle.

Claims

1. An electric vehicle comprising: a motor; a transmission having a forward gear and a reverse gear and transmitting an output of the motor to a drive wheel; and a control device, wherein, when the motor is rotating in a forward direction, the vehicle moves forward when the forward gear is achieved, and moves backward when the reverse gear is achieved, The control device includes: When the electric vehicle is traveling, the motor is controlled to rotate in a forward direction; an electric vehicle, wherein when the transmission is switched to the reverse gear while the electric vehicle is moving forward, reverse rotation of the motor is permitted, that is, rotation in a direction opposite to the forward rotation, and when the electric vehicle is moving backward, the transmission is switched to the forward gear while the electric vehicle is moving backward, the reverse rotation of the motor is permitted.

2. The electric vehicle according to claim 1 , wherein the control device allows the reverse rotation of the motor until the electric vehicle stops.

3. 3 . The electric vehicle according to claim 1 , wherein the control device controls the motor so that torque is output from the motor in a reverse rotation direction when the reverse rotation of the motor is permitted. 4 .

4. 3 . The electric vehicle according to claim 1 , wherein the control device allows the reverse rotation of the motor by setting an output torque of the motor to zero. 4 .

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