Electric vehicle

Abstract

To improve electric power consumption in an automatic operation mode.SOLUTION: An electric vehicle includes: a driving device having a motor for traveling and a power storage device for exchanging power between the motor and the driving device; and a control device for controlling the driving device so as to travel the electric vehicle while switching a manual operation mode and an automatic operation mode, and cutting a creep torque if a creep cut condition is established when the creep torque is output from the motor. The control device alleviates the creep cut condition compared to the manual operation mode, in the automatic operation mode.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, an electric vehicle of this type has been proposed that is equipped with a motor for driving and an electricity storage device that exchanges power with the motor, and that is capable of driving at a very slow speed using the creep torque from the motor, and that is capable of executing creep cut to reduce the creep torque of the electric motor while creep cut conditions are met, that is, the absolute vehicle speed is less than the stopping judgment vehicle speed and the braking force is greater than or equal to a set braking force (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-016168 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such electric vehicles, if, in autonomous driving mode, the same creep cut conditions as in manual driving mode are used to prioritize response to the driver's acceleration requests, it may not be possible to sufficiently suppress power consumption, and sufficient improvement in electricity efficiency may not be achieved.

[0005] The electric vehicle disclosed herein has a primary objective of improving electricity consumption in autonomous driving mode. [Means for solving the problem]

[0006] The electric vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The electric vehicle disclosed herein is A drive device having a motor for running the vehicle and a power storage device for exchanging electric power with the motor; a control device that controls the drive device so as to switch between a manual driving mode and an automatic driving mode and cuts off the creep torque when a creep cut condition is satisfied while a creep torque is being output from the motor; An electric vehicle comprising: The control device relaxes the creep cut condition in the automatic driving mode compared to the manual driving mode. The gist of the present invention is as follows.

[0008] In the electric vehicle disclosed herein, the drive device is controlled to switch between a manual driving mode and an automatic driving mode to run, and further, when a creep cut condition is satisfied while a creep torque is being output from the motor, the creep torque is cut. In this case, in the automatic driving mode, the creep cut condition is relaxed compared to the manual driving mode. As a result, in the automatic driving mode, it is easier to cut the creep torque compared to the manual driving mode, so that the power consumption of the vehicle can be suppressed and the electricity cost can be improved. Of course, in the manual driving mode, a response to the driver's acceleration request can be prioritized.

[0009] In the electric vehicle of the present disclosure, the creep cut condition may be a condition in which, in the manual driving mode, the vehicle speed is equal to or less than a first vehicle speed and the brake is on, and a condition in which, in the autonomous driving mode, the vehicle speed is equal to or less than a second vehicle speed that is equal to or greater than the first vehicle speed.

[0010] In the electric vehicle disclosed herein, the control device may control the motor so that the vehicle speed becomes a target vehicle speed based on the vehicle's current location when in the autonomous driving mode, and the creep cut condition may be a condition in which the vehicle speed is equal to or less than a first vehicle speed and the brake is on when in the manual driving mode, and a condition in which the target vehicle speed is equal to or less than a second vehicle speed that is equal to or greater than the first vehicle speed when in the autonomous driving mode. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram showing the outline of the configuration of an electric vehicle 20. [Diagram 2] 10 is a flowchart illustrating an example of a processing routine. [Diagram 3] 10 is a flowchart illustrating an example of a processing routine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of an electric vehicle 20 according to an embodiment of the present disclosure. As shown in the figure, the electric vehicle 20 of the embodiment includes a drive device 22, a brake device (braking device) 24, a steering device 26, an air conditioner 29, and a main electronic control unit (hereinafter referred to as "main ECU") 30.

[0013] The drive device 22 is configured as a device that rotates and drives a drive shaft 22a that is connected to drive wheels 28a, 28b via a differential gear 27, and includes a motor 22m, an inverter 22i, and a battery 22b. The motor 22m is configured as, for example, a synchronous generator motor, and a rotor of the motor 22m is connected to the drive shaft 22a. The inverter 22i has a plurality of switching elements, and is connected to a power line together with the battery 22b. The motor 22m is rotated and driven by switching of the plurality of switching elements of the inverter 22i.

[0014] The drive device 22 is controlled by a drive electronic control unit (hereinafter referred to as "drive ECU") 23. The drive ECU 23 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, not shown. Signals from various sensors are input to the drive ECU 23 via the input port. For example, the drive ECU 23 receives a rotational position θm from a rotational position sensor that detects the rotational position of the rotor of the motor 22m, and a voltage Vb and a current Ib from a voltage sensor and a current sensor attached to the battery 22b. The drive ECU 23, for example, controls the switching of a plurality of switching elements of the inverter 22i. The drive ECU 23 calculates the rotational speed Nm of the motor 22m (the rotational speed of the drive shaft 22a) based on the rotational position θa of the rotor of the motor 22m from the rotational position sensor. The drive ECU 23 communicates with the main ECU 30 via the communication port.

[0015] The brake device 24 is configured as a well-known hydraulically driven brake device, and is configured to be able to apply a braking force resulting from the brake depression force applied by depressing a brake pedal 48 and a braking force resulting from hydraulic pressure adjustment to the driving wheels 28a, 28b and the driven wheels 28c, 28d. The brake device 24 is controlled by a brake electronic control unit (hereinafter referred to as "brake ECU") 25. Although not shown, the brake ECU 25 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The brake ECU 25 controls, for example, the braking force resulting from the brake depression force applied by the brake device 24 and the braking force resulting from hydraulic pressure adjustment. The brake ECU 25 communicates with the main ECU 30 via the communication port.

[0016] The steering device 26 is mechanically connected to a steering wheel (not shown) and the drive wheels 28a, 28b via a steering shaft, and is equipped with a steering actuator. The steering device 26 steers the drive wheels 28a, 28b based on the driver's operation, and also steers the drive wheels 28a, 28b by driving the actuator based on a steering signal from the main ECU 30.

[0017] The air conditioner 29 has a refrigeration cycle and a blower fan, and conditions the air in the vehicle cabin.

[0018] The main ECU 30 includes a microcomputer having a CPU 31, a ROM 32, a RAM 33, a flash memory 34, and input / output and communication ports (not shown). Signals from various sensors are input to the main ECU 30 via the input ports. For example, an air conditioning command signal from an air conditioning switch 29a that commands the air conditioning device 29 to be turned on and off is input to the main ECU 30. An ignition signal IG from an ignition switch 40, a vehicle speed V from a vehicle speed sensor 41, wheel speeds Vwa to Vwd of the driving wheels 28a, 28b and the driven wheels 28c, 28d from a wheel speed sensor 42, an acceleration α from an acceleration sensor 43, a yaw rate Yr from a yaw rate sensor 44, and a road surface gradient θr from a gradient sensor 45 are input to the main ECU 30. The main ECU 30 also receives an accelerator position AP from an accelerator pedal position sensor 47 that detects the amount of depression of an accelerator pedal 46 , and a brake position BP from a brake pedal position sensor 49 that detects the amount of depression of a brake pedal 48 .

[0019] The main ECU 30, for example, controls the steering device 26, the air conditioning device 29, the display device 70, and the communication device 72. As described above, the main ECU 30 communicates with the drive ECU 23, the brake ECU 25, and the like via communication ports. The main ECU 30 communicates with a shift electronic control unit (hereinafter referred to as "shift ECU") 50, a surroundings recognition electronic control unit (hereinafter referred to as "surroundings recognition ECU") 55, and a navigation device 60 via the communication ports.

[0020] The shift ECU 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, not shown. A shift position signal from a shift position sensor 52 that detects the operation position of a shift lever 51 is input to the shift ECU 50 via an input port. The shift positions include a parking position (P range), a neutral position (N range), a drive position (D range), and a reverse position (R range). The shift ECU 50 is connected to the main ECU 30 and the surrounding recognition ECU 55 via a communication port, and sets a shift position based on the shift position signal from the shift position sensor 52 and a control signal from the surrounding recognition ECU 55, and transmits the set shift position to the main ECU 30.

[0021] Although not shown, the surrounding recognition ECU 55 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Various signals are input to the surrounding recognition ECU 55 via the input port. For example, the surrounding recognition ECU 55 may include a signal indicating information on the vehicle and its surroundings from the surrounding recognition device 56 (for example, the distances D1 and D2 between the vehicle and other vehicles in front and behind the vehicle, and the vehicle's running position in the lane on the road surface, etc.), a mode signal from the automatic driving switch 57, etc. Examples of the surrounding recognition device 56 may include a camera, a millimeter wave radar, a quasi-millimeter wave radar, an infrared laser radar, and a sonar. The automatic driving switch 57 is a switch for switching between a manual driving mode in which the driver performs driving operations and an automatic driving mode in which the driver does not perform driving operations. As described above, the surrounding recognition ECU 55 communicates with the main ECU 30 and the shift ECU 50 via the communication port.

[0022] The navigation device 60 includes a main body 61 with a built-in control unit, a GPS antenna 62 that receives information about the current location of the vehicle, and a display 63. The control unit of the main body 61 has a storage medium (e.g., a hard disk or SSD) in which map information and the like are stored, an input / output port, and a communication port. The map information includes service information (e.g., tourist information, parking lots, etc.) and road information for each driving section (e.g., between traffic lights and between intersections) stored as a database. The road information includes distance information, road width information, number of lanes information, area information (urban area or suburban area), type information (general road or expressway), gradient information, legal speed limit, number of traffic lights, turning radius of each curve, and the like. The display 63 is configured as a touch panel display that displays various information such as information about the current location of the vehicle and a planned driving route to the destination, and allows the user to input various instructions. When a destination is set by a user operating the display 63, the main body 61 of the navigation device 60 sets a planned driving route from the current location of the vehicle to the destination based on map information stored in the main body 61 and the current location and destination of the vehicle obtained from the GPS antenna 62, and displays the set planned driving route on the display 63 to provide route guidance.

[0023] In the electric vehicle 20 of the embodiment thus configured, the vehicle travels by switching between a manual driving mode (the automatic driving switch 57 is off) and an automatic driving mode (the automatic driving switch 57 is on). In the manual driving mode, the main ECU 30 sets a required torque Td* for traveling based on the accelerator position AP, the brake position BP, and the vehicle speed V, and controls the motor 22m (the inverter 22i) and the brake device 24 so as to travel with the set required torque Td*. In the embodiment, when the accelerator is off and the vehicle speed V is equal to or less than a threshold value Vref0, it is determined that the creep torque condition is satisfied, the creep torque is set to the required torque Td*, and the motor 22m is controlled so as to output the creep torque from the motor 22m to the drive shaft 22a. The threshold value Vref0 is, for example, about 5km / h to 10km / h.

[0024] In the automatic driving mode, the main ECU 30 sets the target vehicle speed V* based on information from the navigation device 60 (e.g., a planned travel route, the current location of the vehicle, map information, etc.) and information from the surrounding recognition device 56 (e.g., information on the vehicle and its surroundings), sets the required torque Td* so that the vehicle speed V becomes the target vehicle speed V*, and controls the motor 22m (inverter 22i), the brake device 24, and the steering device 26 so that the vehicle travels along the planned travel route at the required torque Td*. In the embodiment, when the vehicle speed V and the target vehicle speed V* are equal to or less than the threshold value Vref0, it is determined that the creep torque condition is satisfied, the creep torque is set to the required torque Td*, and the motor 22m is controlled so that the creep torque is output from the motor 22m to the drive shaft 22a. Note that the creep torque condition may be, instead of the condition that the vehicle speed V and the target vehicle speed V* are equal to or less than the threshold value Vref0, a condition that at least one of the vehicle speed V and the target vehicle speed V* is equal to or less than the threshold value Vref0, or the like.

[0025] Next, the operation of the electric vehicle 20 of this embodiment, particularly the operation when creep torque is being output from the motor 22m to the drive shaft 22a, will be described. Figure 2 is a flowchart showing an example of a processing routine executed by the main ECU 30. This routine is repeatedly executed when creep torque is being output from the motor 22m to the drive shaft 22a.

[0026] When this routine is executed, the main ECU 30 judges whether the driving mode is manual or automatic (step S100). When the driving mode is judged to be manual, the main ECU 30 judges whether the vehicle speed V is equal to or lower than a threshold Vref1 (step S110) and judges whether the brake is on (step S120). Here, the threshold Vref1 is a threshold used to judge whether the vehicle is stopped in the manual driving mode. The threshold Vref1 is set as a vehicle speed lower than the above-mentioned threshold Vref0, and is set to, for example, about 0 km / h to several km / h. The process of judging whether the brake is on can be performed by judging at least one of, for example, whether the brake pedal 48 is depressed, whether the braking force is applied from the brake device 24 to the driving wheels 28a, 28b and the driven wheels 28c, 28d, and the like. The processes of steps S110 and S120 are processes of judging whether a creep cut condition for cutting the creep torque is satisfied in the manual driving mode.

[0027] When it is determined in step S110 that the vehicle speed V is higher than the threshold value Vref1, or when it is determined in step S120 that the brake is off, it is determined that the creep cut condition is not satisfied, and the cut of the creep torque is prohibited (step S150), and this routine is terminated. In this case, the creep torque is output from the motor 22m to the drive shaft 22a.

[0028] When it is determined in step S110 that the vehicle speed V is equal to or lower than the threshold value Vref1 and when it is determined in step S120 that the brake is on, it is determined that the creep cut condition is satisfied, and the creep torque is cut (step S140), and this routine ends. In this case, the creep torque is not output from the motor 22m to the drive shaft 22a.

[0029] When it is determined in step S100 that the vehicle is in the automatic driving mode, it is determined whether or not the vehicle speed V is equal to or lower than a threshold value Vref1 (step S130). The process of step S130 is a process for determining whether or not a creep cut condition is satisfied in the automatic driving mode.

[0030] When it is determined in step S130 that the vehicle speed V is higher than the threshold value Vref1, it is determined that the creep cut condition is not satisfied, the cut of the creep torque is prohibited (step S150), and this routine is terminated. On the other hand, when it is determined in step S130 that the vehicle speed V is equal to or lower than the threshold value Vref1, it is determined that the creep cut condition is satisfied, the cut of the creep torque is executed (step S150), and this routine is terminated.

[0031] In this way, in the manual driving mode, the creep cut condition is that the vehicle speed V is equal to or less than the threshold value Vref1 and the brake is on, whereas in the automatic driving mode, the creep cut condition is that the vehicle speed V is equal to or less than the threshold value Vref1. That is, in the automatic driving mode, the creep cut condition is relaxed (made easier to be met) compared to the manual driving mode. As a result, in the automatic driving mode, it is easier to cut the creep torque compared to the manual driving mode, so that the power consumption of the vehicle can be suppressed and the electricity cost can be improved. Of course, in the manual driving mode, it is possible to prioritize the response to the driver's acceleration request.

[0032] In the electric vehicle 20 of the present embodiment described above, when creep torque is output from the motor 22m to the drive shaft 22a, if the creep cut condition is satisfied, the creep torque is cut. In this case, in the automatic driving mode, the creep cut condition is relaxed (made easier to be satisfied) compared to the manual driving mode. As a result, in the automatic driving mode, it is easier to cut the creep torque compared to the manual driving mode, so that the power consumption of the vehicle can be suppressed and the electricity cost can be improved. Of course, in the manual driving mode, it is possible to prioritize the response to the driver's acceleration request.

[0033] In the above-described embodiment, the main ECU 30 executes the processing routine of Fig. 2, but instead of this, the main ECU 30 may execute the processing routine of Fig. 3. The processing routine of Fig. 3 differs from the processing routine of Fig. 2 in that the processing of step S130 is replaced with the processing of step S132.

[0034] In the processing routine of Fig. 3, when it is determined in step S100 that the automatic driving mode is selected, it is determined whether or not the target vehicle speed V* is equal to or lower than the threshold value Vref1 (step S132). When it is determined that the target vehicle speed V* is higher than the threshold value Vref1, it is determined that the creep cut condition is not satisfied, and the cut of the creep torque is prohibited (step S150), and this routine is terminated. On the other hand, when it is determined that the target vehicle speed V* is equal to or lower than the threshold value Vref1, it is determined that the creep cut condition is satisfied, and the cut of the creep torque is executed (step S150), and this routine is terminated.

[0035] When considering a case where the vehicle decelerates and stops, the target vehicle speed V* decreases before the vehicle speed V decreases. Therefore, the vehicle speed V reaches the threshold value Vref1 after the target vehicle speed V* reaches the threshold value Vref1. Therefore, instead of using the condition that the vehicle speed V is equal to or less than the threshold value Vref1 as in step S130 of the processing routine of FIG. 2, by using the condition that the target vehicle speed V* is equal to or less than the threshold value Vref1, it is possible to cut the creep torque at an earlier timing when the vehicle decelerates and stops. This makes it possible to further suppress the power consumption of the vehicle.

[0036] In the above embodiment, in the processing routine of FIG. 2, the same threshold value Vref1 is used to determine whether the vehicle is stopped in the manual driving mode and whether the vehicle is stopped in the automatic driving mode. However, the threshold value Vref1 may be used to determine whether the vehicle is stopped in the manual driving mode, and the threshold value Vref2 higher than the threshold value Vref1 and lower than the threshold value Vref0 may be used to determine whether the vehicle is stopped in the automatic driving mode. In this way, it becomes easier to cut the creep torque in the automatic driving mode, so that the power consumption of the vehicle can be suppressed. The processing routine of FIG. 3 may also be modified in the same manner.

[0037] In the above-described embodiment, the electric vehicle 20 is provided with the motor 22m, the inverter 22i, and the battery 22b as the drive device 22. However, the electric vehicle 20 may be provided with a hybrid vehicle having an engine in addition to the motor, inverter, and battery as the drive device, or may be provided with a fuel cell vehicle having a fuel cell in addition to the motor, inverter, and battery as the drive device.

[0038] The relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be described. In the embodiment, the drive device 22 having the motor 22m and the battery 22b corresponds to the "drive device", and the main ECU 30, the drive ECU 23, etc. correspond to the "control device".

[0039] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the embodiment is an example for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the Means for Solving the Problem column.

[0040] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure. [Industrial Applicability]

[0041] The present disclosure can be used in the electric vehicle manufacturing industry and the like. [Explanation of symbols]

[0042] 20 electric vehicle, 22 drive unit, 22a drive shaft, 22b battery, 22i inverter, 22m motor, 23 drive ECU, 24 brake unit, 25 brake ECU, 26 steering unit, 27 differential gear, 28a drive wheel, 28c driven wheel, 29 air conditioner, 29a air conditioner switch, 30 main ECU, 31 CPU, 32 ROM, 33 RAM, 34 flash memory, 40 ignition switch, 41 vehicle speed sensor, 42 wheel speed sensor, 43 acceleration sensor, 44 yaw rate sensor, 45 gradient sensor, 46 accelerator pedal, 47 accelerator pedal position sensor, 48 brake pedal, 49 brake pedal position sensor, 50 shift ECU, 51 shift lever, 52 shift position sensor, 55 surrounding recognition ECU, 56 surrounding recognition device, 57 automatic driving switch, 60 Navigation device, 61 main body, 62 GPS antenna, 63 display, 70 display device, 72 communication device.

Claims

1. A drive device having a motor for running the vehicle and a power storage device for exchanging electric power with the motor; a control device that controls the drive device so as to switch between a manual driving mode and an automatic driving mode and cuts off the creep torque when a creep cut condition is satisfied while a creep torque is being output from the motor; An electric vehicle comprising: The control device relaxes the creep cut condition in the automatic driving mode compared to the manual driving mode. Electric car.

2. The electric vehicle according to claim 1, The creep cut condition is: In the manual driving mode, the vehicle speed is equal to or lower than a first vehicle speed and the brake is on. In the automatic driving mode, the vehicle speed is equal to or lower than a second vehicle speed that is equal to or higher than the first vehicle speed. Electric car.

3. The electric vehicle according to claim 1, The control device controls the motor when in the autonomous driving mode so that the vehicle speed becomes a target vehicle speed based on a current location of the vehicle, The creep cut condition is: In the manual driving mode, the vehicle speed is equal to or lower than a first vehicle speed and the brake is on. In the automatic driving mode, the target vehicle speed is equal to or lower than a second vehicle speed that is equal to or higher than the first vehicle speed. Electric car.

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