Control device

Abstract

To improve responsiveness of acceleration.SOLUTION: A control device is a control device for a vehicle including a brake deice and a motor as a drive source, and includes one or a plurality of processors, and one or a plurality of memories connected to the processor. The processor executes processing including switching of a mode of brake control for braking the vehicle according to brake operation by a driver between a first brake mode and a second brake mode. The first brake mode is a mode in which the brake device operates while regenerative brake force is applied on the vehicle by the motor. The second brake mode is a mode in which the brake device operates while the drive force is applied on the vehicle by the motor so that brake force applied on the vehicle by the brake device becomes larger as compared with the first brake mode.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a control device.

Background Art

[0002] Vehicles equipped with a motor as a drive source are widely used. In such a vehicle, for example, as disclosed in Patent Document 1, the vehicle can be braked (that is, decelerated) by using regenerative braking by the motor. In regenerative braking by the motor, a regenerative braking force, which is a braking force by regenerative braking, is applied to the vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a vehicle equipped with a motor as a drive source, the vehicle can be accelerated by applying a driving force to the vehicle by the motor. The direction of the torque of the motor is reversed between the state where a regenerative braking force is applied to the vehicle by the motor and the state where a driving force is applied to the vehicle by the motor. Here, when the direction of the torque of the motor is reversed, in order to reduce the shock caused by backlash in the power transmission path, the time change rate of the torque of the motor (that is, the torque change rate) is limited. Therefore, when accelerating after braking the vehicle, the responsiveness of acceleration decreases.

[0005] Therefore, an object of the present invention is to provide a control device capable of improving the responsiveness of acceleration.

Means for Solving the Problems

[0006] To solve the above problems, a control device according to an embodiment of the present invention is a control device for a vehicle including a braking device and a motor as a drive source, one or more processors, one or more memories connected to the processor, and has the processor executes a process including switching a braking control mode for braking the vehicle in response to a braking operation by a driver the brake pedal between a first braking mode and a second braking mode, control and is executed when the braking operation is being performed the first braking mode is a mode in which the braking device operates while a regenerative braking force is applied to the vehicle by the motor, the second braking mode is a mode in which the braking device operates such that a braking force applied to the vehicle by the braking device becomes greater than that in the first braking mode while a driving force is applied to the vehicle by the motor, when the braking control mode is set to the first braking mode, if the braking operation is performed, the processor executes the first braking mode, when the braking control mode is set to the second braking mode, if the braking operation is performed, the processor executes the second braking mode, when the braking control mode is set to the second braking mode, if the braking operation is released during the execution of the second braking mode, the processor ends the second braking mode and continues to apply the driving force to the vehicle by the motor until an accelerator operation by the driver is started, In the first braking mode, controlling the motor and the braking device so that a required braking force corresponding to the operation amount of the braking operation is applied to the vehicle; In the second braking mode, controlling the motor and the braking device so that the required braking force is applied to the vehicle; and executes a process including .

Advantages of the Invention

[0007] ​According to the present invention, it is possible to improve the responsiveness of acceleration.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to avoid redundant description, and elements not directly related to the present invention are not shown.

[0010] <Configuration of Vehicle> With reference to FIGS. 1 and 2, the configuration of a vehicle 1 according to an embodiment of the present invention will be described.

[0011] FIG. 1 is a schematic diagram showing a schematic configuration of the vehicle 1. As shown in FIG. 1, the vehicle 1 includes wheels 11, a power transmission system 12, a motor 21, an inverter 22, a battery 23, a brake device 31, a hydraulic control unit 32, a master cylinder 33, an accelerator pedal 41, a brake pedal 42, an input device 43, an accelerator opening sensor 51, a brake sensor 52, a vehicle speed sensor 53, a motor temperature sensor 54, a battery sensor 55, and a control device 100.

[0012] The vehicle 1 is an electric vehicle that includes only the motor 21, which is a driving motor, as a driving source, and travels using the power output from the motor 21. However, the vehicle according to the present invention is not limited to this example, and for example, it may be a hybrid vehicle that includes an engine as a driving source in addition to the motor 21.

[0013] The motor 21 outputs power transmitted to the wheels 11. The motor 21 is, for example, a three-phase alternating current motor. The motor 21 is connected to the battery 23 via the inverter 22, and is driven using the power of the battery 23 to output power. The output shaft of the motor 21 is connected to the wheels 11 via the power transmission system 12. The power output from the motor 21 is transmitted to the wheels 11 via the power transmission system 12. In this case, a driving force is applied to the vehicle 1 by the motor 21, and the vehicle 1 accelerates.

[0014] In the vehicle 1, the drive wheels to which the power output from the motor 21 is transmitted may be the front wheels or the rear wheels. Further, the power output from the output side of the power transmission system 12 may be transmitted to both the front wheels and the rear wheels via a propeller shaft (not shown).

[0015] The motor 21 can generate electricity using the kinetic energy of the wheel 11. The electric power generated by the motor 21 is supplied to the battery 23 via the inverter 22. Thereby, the battery 23 is charged by the electric power generated by the motor 21. In this case, a regenerative braking force (i.e., the braking force by regenerative braking) is applied to the vehicle 1 by the motor 21, and the vehicle 1 is braked (i.e., decelerated).

[0016] The inverter 22 is a power conversion device that performs bidirectional power conversion. For example, the inverter 22 includes a three-phase bridge circuit. The inverter 22 can convert the DC power supplied from the battery 23 into AC power and supply it to the motor 21. Also, the inverter 22 can convert the AC power generated by the motor 21 into DC power and supply it to the battery 23.

[0017] The battery 23 is a battery that can charge and discharge electric power. As the battery 23, for example, a lithium-ion battery, a lithium-ion polymer battery, a nickel-metal hydride battery, a nickel-cadmium battery, or a lead-acid battery is used. However, other batteries may be used as the battery 23. The battery 23 stores the electric power supplied to the motor 21.

[0018] The master cylinder 33 is connected to the brake pedal 42 via a force multiplier device (not shown), and generates hydraulic pressure according to the brake operation amount, which is the operation amount of the brake pedal 42. The master cylinder 33 is connected to the brake device 31 provided on each wheel 11 via the hydraulic control unit 32. The hydraulic pressure generated by the master cylinder 33 is supplied to each brake device 31 via the hydraulic control unit 32.

[0019] The braking device 31 applies a braking force to the wheels 11 using hydraulic pressure. The sum of the braking forces applied by each braking device 31 to each wheel 11 corresponds to the braking force applied to the vehicle 1 by the braking device 31.

[0020] The braking device 31 has, for example, a brake caliper (not shown) including a brake pad and a wheel cylinder. The brake pads are provided in a pair so as to face each other on both side surfaces of a brake disk that rotates integrally with the wheel 11, for example. The wheel cylinder is formed inside the brake caliper, and a piston is slidably provided inside the wheel cylinder. The tip of the piston is provided to face the brake pad, and the brake pad is configured to move toward each side surface of the brake disk as the piston slides. The hydraulic pressure generated by the master cylinder 33 is supplied to the wheel cylinder of the braking device 31. Thereby, the piston and the brake pad inside the brake caliper move, and both side surfaces of the brake disk are clamped by the pair of brake pads, and a braking force is applied to the wheel 11.

[0021] The hydraulic control unit 32 can adjust the hydraulic pressure supplied to each braking device 31 (that is, the brake hydraulic pressure of each braking device 31). Specifically, the hydraulic control unit 32 has devices such as a pump and a control valve, and the brake hydraulic pressure of each braking device 31 is controlled by controlling the operations of these devices. Thereby, the braking force applied to each wheel 11 is controlled. The hydraulic control unit 32 may be able to individually adjust the hydraulic pressure supplied to each braking device 31. Also, the brake system may be of two systems.

[0022] The accelerator pedal 41 receives an accelerator operation by the driver. Specifically, the accelerator operation is an operation of stepping on the accelerator pedal 41.

[0023] The brake pedal 42 receives a brake operation by the driver. Specifically, the brake operation is an operation of stepping on the brake pedal 42.

[0024] The input device 43 receives various operations by the driver. The input device 43 is, for example, a paddle provided on the steering wheel. The driver can perform an operation of pulling the paddle forward. However, the input device 43 is not limited to this example. For example, the input device 43 may be a device other than the paddle (e.g., a push button, etc.). Also, for example, the installation position of the input device 43 may be other than the steering wheel.

[0025] The accelerator opening sensor 51 detects the accelerator opening, which is the operation amount of the accelerator pedal 41 by the driver, and outputs the detection result to the control device 100.

[0026] The brake sensor 52 detects the brake operation amount, which is the operation amount of the brake pedal 42 by the driver, and outputs the detection result to the control device 100.

[0027] The vehicle speed sensor 53 detects the vehicle speed, which is the speed of the vehicle 1, and outputs the detection result to the control device 100.

[0028] The motor temperature sensor 54 detects the motor temperature (that is, the temperature of the motor 21), and outputs the detection result to the control device 100.

[0029] The battery sensor 55 detects various information related to the battery 23, and outputs the detection result to the control device 100. The information detected by the battery sensor 55 includes the remaining capacity of the battery 23 (hereinafter also referred to as SOC).

[0030] The control device 100 includes one or more processors 101 and one or more memories 102 connected to the processor 101. The processor 101 includes, for example, a CPU (Central Processing Unit). The memory 102 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM is a storage element that stores programs and arithmetic parameters used by the CPU. The RAM is a storage element that temporarily stores data such as variables and parameters used in the processes executed by the CPU.

[0031] The control device 100 communicates with each device provided in the vehicle 1 (for example, the inverter 22, the hydraulic control unit 32, the input device 43, the accelerator opening sensor 51, the brake sensor 52, the vehicle speed sensor 53, the motor temperature sensor 54, and the battery sensor 55, etc.). The communication between the control device 100 and each device is realized by using, for example, CAN (Controller Area Network) communication.

[0032] FIG. 2 is a block diagram showing an example of the functional configuration of the control device 100. For example, as shown in FIG. 2, the control device 100 includes an acquisition unit 111 and a control unit 112. Note that various processes including the processes described below performed by the acquisition unit 111 or the control unit 112 can be executed by the processor 101. Specifically, by the processor 101 executing the programs stored in the memory 102, various processes are executed.

[0033] The acquisition unit 111 acquires various information used in the processes performed by the control unit 112 and outputs it to the control unit 112. For example, the acquisition unit 111 acquires information from the input device 43, the accelerator opening sensor 51, the brake sensor 52, the vehicle speed sensor 53, the motor temperature sensor 54, and the battery sensor 55.

[0034] The control unit 112 controls the operations of each device in the vehicle 1. For example, the control unit 112 includes a motor control unit 112a, a brake control unit 112b, a setting unit 112c, and a determination unit 112d.

[0035] The motor control unit 112a controls the operation of the motor 21. Specifically, the motor control unit 112a controls the supply of power between the battery 23 and the motor 21 by controlling the operation of the switching elements of the inverter 22. Thereby, the motor control unit 112a can control the generation and power generation of power by the motor 21. Therefore, the motor control unit 112a can control the driving force applied to the vehicle 1 by the motor 21. Also, the motor control unit 112a can control the regenerative braking force applied to the vehicle 1 by the motor 21.

[0036] The brake control unit 112b controls the operation of the brake device 31. Specifically, the brake control unit 112b controls the brake hydraulic pressure of each brake device 31 provided for each wheel 11 by controlling the operation of the hydraulic control unit 32. Thereby, the brake control unit 112b can control the braking force applied to the vehicle 1 by the brake device 31.

[0037] As described above, the control unit 112 can brake the vehicle 1 by controlling the motor 21 and the brake device 31. The control unit 112 executes brake control in response to a brake operation by the driver. The brake control is control for braking the vehicle 1 and is executed when a brake operation is being performed.

[0038] Here, the control unit 112 switches the mode of the brake control between a first brake mode and a second brake mode. The first brake mode is a mode in which the braking device 31 operates while the regenerative braking force is applied to the vehicle 1 by the motor 21. The second brake mode is a mode in which the braking device 31 operates so that the braking force applied to the vehicle 1 by the braking device 31 becomes larger than that in the first brake mode while the driving force is applied to the vehicle 1 by the motor 21. The brake control is executed by the motor control unit 112a and the brake control unit 112b. Details of the brake control will be described later.

[0039] The setting unit 112c sets various parameters used in the processes performed by the control unit 112.

[0040] The determination unit 112d performs various determinations. The control unit 112 performs various processes based on the determination results by the determination unit 112d.

[0041] Note that the functions of the control device 100 according to the present embodiment may be divided into a plurality of control devices, or a plurality of functions may be realized by one control device. When the functions of the control device 100 are divided into a plurality of control devices, the plurality of control devices may be connected to each other via a communication bus such as CAN.

[0042] <Operation of the control device> Subsequently, with reference to FIGS. 3 to 8, the operation of the control device 100 according to the embodiment of the present invention will be described.

[0043] As described above, the control unit 112 switches the mode of the brake control between the first brake mode and the second brake mode. As will be described later, in the present embodiment, by executing the second brake mode in addition to the first brake mode as the brake control mode, it is possible to improve the acceleration responsiveness.

[0044] FIG. 3 is a flowchart showing an example of the main processing flow regarding the second braking mode performed by the control device 100. The control flow shown in FIG. 3 is repeatedly started after completion.

[0045] The control flow shown in FIG. 3 starts in a situation where the mode of the brake control is set to the first braking mode. When the mode of the brake control is set to the first braking mode, when a braking operation is performed, the control unit 112 executes the first braking mode.

[0046] In the first braking mode, the control unit 112 operates the brake device 31 while applying a regenerative braking force to the vehicle 1 by the motor 21. In the first braking mode, the control unit 112 controls the motor 21 and the brake device 31 so that a required braking force (that is, a required value of the braking force) corresponding to the braking operation amount is applied to the vehicle 1. In the first braking mode, the control unit 112 controls the motor 21 and the brake device 31 so that, for example, the shortage of the regenerative braking force with respect to the required braking force is compensated by the braking force of the brake device 31.

[0047] When the control flow shown in FIG. 3 is started, first, in step S101, the determination unit 112d of the control unit 112 determines whether or not a setting operation by the driver has been performed. The setting operation is an operation for setting the mode of the brake control to the second braking mode. The driver performs the setting operation using, for example, the input device 43. When the input device 43 is a paddle provided on the steering wheel, for example, an operation of pulling the paddle once corresponds to the setting operation. However, the setting operation is not limited to this example.

[0048] If it is determined that the setting operation has not been performed (if it is determined NO in step S101), the control flow shown in FIG. 3 ends. On the other hand, if it is determined that the setting operation has been performed (if it is determined YES in step S101), the process proceeds to step S102.

[0049] If it is determined YES in step S101, in step S102, the setting unit 112c of the control unit 112 sets the mode of the brake control to the second brake mode.

[0050] Next, in step S103, the determination unit 112d of the control unit 112 determines whether or not the brake operation by the driver has started. The determination unit 112d determines whether or not the brake operation has started based on, for example, the detection result of the brake sensor 52.

[0051] If it is determined that the brake operation has not started (if it is determined NO in step S103), step S103 is repeated. On the other hand, if it is determined that the brake operation has started (if it is determined YES in step S103), the process proceeds to step S104.

[0052] If it is determined YES in step S103, in step S104, the control unit 112 executes the second brake mode.

[0053] In the second brake mode, the control unit 112 operates the brake device 31 while applying a driving force to the vehicle 1 by the motor 21. In the second brake mode, the control unit 112 controls the motor 21 and the brake device 31 so that a required braking force corresponding to the brake operation amount is applied to the vehicle 1.

[0054] Specifically, in the second brake mode, the control unit 112 controls the motor 21 and the brake device 31 so that the braking force by the brake device 31 becomes a value larger than the driving force by the motor 21 by the amount of the required braking force. That is, in the second brake mode, the absolute value of the braking force by the brake device 31 is the sum of the absolute value of the driving force by the motor 21 and the absolute value of the required braking force. Therefore, in the second brake mode, the braking force applied to the vehicle 1 by the brake device 31 becomes larger than in the first brake mode. Note that the details of the driving force in the second brake mode (that is, the driving force applied to the vehicle 1 by the motor 21 in the second brake mode) will be described later.

[0055] Next, in step S105, the determination unit 112d of the control unit 112 determines whether or not the brake operation by the driver has been released. The determination unit 112d determines whether or not the brake operation has been released based on, for example, the detection result of the brake sensor 52.

[0056] If it is determined that the brake operation has not been released (if it is determined NO in step S105), the process returns to step S104. On the other hand, if it is determined that the brake operation has been released (if it is determined YES in step S105), the process proceeds to step S106.

[0057] If it is determined YES in step S105, in step S106, the control unit 112 ends the second brake mode. Next, in step S107, the control unit 112 continues to apply the driving force to the vehicle 1 by the motor 21.

[0058] Next, in step S108, the determination unit 112d of the control unit 112 determines whether or not the accelerator operation by the driver has been started. The determination unit 112d determines whether or not the accelerator operation has been started based on, for example, the detection result of the accelerator opening sensor 51.

[0059] If it is determined that the accelerator operation has not been started (if it is determined NO in step S108), the process returns to step S107. On the other hand, if it is determined that the accelerator operation has been started (if it is determined YES in step S108), the process proceeds to step S109.

[0060] If it is determined YES in step S108, in step S109, the setting unit 112c of the control unit 112 sets the mode of the brake control to the first brake mode, and the control flow shown in FIG. 3 ends.

[0061] FIG. 4 is a diagram showing an example of the transition of various state quantities when a brake operation and an accelerator operation are sequentially performed during the running of the vehicle 1. In FIG. 4, as various state quantities, the transition of each of the execution state of the setting operation, the execution state of the accelerator operation, the execution state of the brake operation, the motor torque (that is, the torque of the motor 21), the braking force by the brake device 31, and the vehicle speed is shown. When each of the setting operation, the accelerator operation, and the brake operation is ON, each operation is being performed. When each of the setting operation, the accelerator operation, and the brake operation is OFF, each operation is not being performed. When the motor torque becomes a positive value, a driving force is applied to the vehicle 1 by the motor 21. When the motor torque becomes a negative value, a regenerative braking force is applied to the vehicle 1 by the motor 21.

[0062] Note that in FIG. 4, the various state quantities transition as shown by the solid line. The transition shown by the broken line in FIG. 4 is the transition of the various state quantities when the brake control mode is temporarily set to the first brake mode before the time point T1.

[0063] In the example shown in FIG. 4, before the time point T1, the vehicle 1 is running in a state where the brake operation is not performed and the accelerator operation is being performed. Note that before the time point T1, the brake control mode is set to the first brake mode. Then, at the time point T1, the setting operation is performed, and the brake control mode is set to the second brake mode. Thereafter, at the time point T2, the accelerator operation is released and the brake operation is started. Therefore, after the time point T2, the second brake mode is executed.

[0064] After the time point T2, since the second brake mode is executed, the motor torque becomes a positive value, and a driving force is applied to the vehicle 1 by the motor 21. Also, the brake device 31 operates, and a braking force is applied to the vehicle 1 by the brake device 31.

[0065] Here, during the execution of the second braking mode, the control unit 112 applies, for example, a driving force corresponding to the running resistance of the vehicle 1 to the vehicle 1 by the motor 21. The running resistance of the vehicle 1 increases as the vehicle speed increases. Therefore, the control unit 112 controls the driving force applied to the vehicle 1 by the motor 21 to increase as the vehicle speed increases. Thereby, the control unit 112 can control the driving force applied to the vehicle 1 by the motor 21 to a driving force corresponding to the running resistance of the vehicle 1 (that is, a driving force that matches the running resistance or a driving force close to the running resistance). Specifically, it is preferable that the control unit 112 further takes into account the gear ratio in the power transmission system 12 and the tire diameter of the wheels 11, etc., and controls the driving force applied to the vehicle 1 by the motor 21.

[0066] At a time point T3 after the time point T2, the braking operation is released and the accelerator operation is started. Therefore, at the time point T3, the second braking mode ends. Accordingly, at the time point T3, the supply of hydraulic pressure to the brake device 31 stops, and after the time point T3, the application of braking force to the vehicle 1 by the brake device 31 ends. Also, after the time point T3, the control unit 112 controls the motor torque according to the accelerator opening. Thereby, at a time point T4 after the time point T3, the vehicle 1 starts to accelerate. Note that at the time point T3, the braking control mode is set to the first braking mode.

[0067] Incidentally, in the example shown by the dashed line, after the time point T1, the braking control mode is set to the first braking mode. Therefore, after the time point T2 when the braking operation is started, the motor torque becomes a negative value, and a regenerative braking force is applied to the vehicle 1 by the motor 21. Also, the brake device 31 operates, and a braking force is applied to the vehicle 1 by the brake device 31. In both the first braking mode and the second braking mode, the motor 21 and the brake device 31 are controlled so that the required braking force is applied to the vehicle 1. Therefore, in the example shown by the dashed line (that is, the example in which the first braking mode is executed), the braking force by the brake device 31 is smaller than that in the example shown by the solid line (that is, the example in which the second braking mode is executed).

[0068] Here, in the example shown by the dashed line, at time point T3 when the brake operation is released and the accelerator operation is started, the motor torque is a negative value. Therefore, after time point T3, in the process of the motor torque increasing, the motor torque switches from a negative value to a positive value. Thus, when the direction of the motor torque reverses, in order to reduce the shock caused by backlash in the power transmission path (for example, the power transmission system 12), the time change rate of the motor torque is limited. For example, when the motor torque is within a predetermined range near 0 Nm, the control unit 112 limits the time change rate of the motor torque to a predetermined value or less. Therefore, as shown in region R1 in FIG. 4, when the motor torque switches from a negative value to a positive value, the time change rate of the motor torque becomes small. Thereby, in the example shown by the dashed line, at time point T5 after time point T4, the vehicle 1 starts to accelerate.

[0069] On the other hand, in the present embodiment shown by the solid line, after time point T1, the brake control mode is set to the second brake mode. Thereby, at time point T3 when the brake operation is released and the accelerator operation is started, the motor torque is a positive value. Therefore, when accelerating the vehicle 1 after braking, it is possible to suppress the reversal of the direction of the motor torque. Thus, it is possible to suppress the limitation of the time change rate of the motor torque. Therefore, the acceleration responsiveness can be improved.

[0070] As described above, the driving force in the second braking mode (i.e., the driving force applied to the vehicle 1 by the motor 21 in the second braking mode) is, for example, a driving force corresponding to the running resistance of the vehicle 1. Here, when the driving force in the second braking mode matches the running resistance of the vehicle 1, compared with the case where the driving force in the second braking mode is greater than the running resistance of the vehicle 1, it is possible to suppress sudden acceleration during re-acceleration of the vehicle 1 after the end of the second braking mode. Also, when the driving force in the second braking mode matches the running resistance of the vehicle 1, compared with the case where the driving force in the second braking mode is smaller than the running resistance of the vehicle 1, it is possible to further improve the acceleration responsiveness during re-acceleration of the vehicle 1 after the end of the second braking mode. Therefore, it is preferable that the control unit 112 applies, by the motor 21 to the vehicle 1, a driving force corresponding to the running resistance of the vehicle 1 during the execution of the second braking mode.

[0071] FIG. 5 is a diagram showing an example different from the example of FIG. 4 of the transition of various state quantities when a brake operation and an accelerator operation are sequentially performed during the running of the vehicle 1. In FIG. 5, similar to FIG. 4, as various state quantities, the transition of each of the execution state of the setting operation, the execution state of the accelerator operation, the execution state of the brake operation, the motor torque, the braking force by the brake device 31, and the vehicle speed is shown.

[0072] In the example shown in FIG. 5, before the time point T3, the transition of various state quantities is the same as the example of FIG. 4. Here, in the example shown in FIG. 5, different from the example of FIG. 4, the accelerator operation is not started at the time point T3 when the brake operation is released. At the time point T6 after the time point T3, the accelerator operation is started. At the time point T3, the control unit 112 ends the second braking mode. And between the time point T3 and the time point T6, the control unit 112 continues to apply the driving force to the vehicle 1 by the motor 21. During this period, it is preferable that the control unit 112 applies, by the motor 21 to the vehicle 1, a driving force corresponding to the running resistance of the vehicle 1 in the same manner as during the execution of the second braking mode. And after the time point T6 when the accelerator operation is started, the control unit 112 controls the motor torque according to the accelerator opening. Thereby, at the time point T7 after the time point T6, the vehicle 1 starts to accelerate.

[0073] As described above, when the brake operation is released during the execution of the second brake mode, the control unit 112 ends the second brake mode and continues to apply the driving force to the vehicle 1 by the motor 21 until the accelerator operation is started. Therefore, in the example of FIG. 5, the application of the driving force to the vehicle 1 by the motor 21 continues from time point T3 to time point T6. Thereby, during the period from the time when the second brake mode ends until the accelerator operation is started, the regenerative braking by the motor 21 is performed, and it is suppressed that the motor torque becomes a negative value. Therefore, when accelerating the vehicle 1 after braking, it is possible to more appropriately suppress the reversal of the direction of the motor torque. Therefore, it is possible to more appropriately suppress the limitation of the time change rate of the motor torque. Therefore, the acceleration responsiveness can be more appropriately improved.

[0074] In the above, with reference to the flowchart of FIG. 3, the main processing flow regarding the second brake mode has been described. However, the control device 100 may perform processing other than the processing described above as processing related to brake control. Hereinafter, with reference to FIGS. 6 to 8, the processing other than the processing described above performed by the control device 100 will be described.

[0075] FIG. 6 is a flowchart showing an example of the processing flow regarding the setting of the upper limit value of the time change rate of the motor torque performed by the control device 100. The control flow shown in FIG. 6 may be executed after the control flow shown in FIG. 3 ends, or may be executed by interrupting during the execution of the control flow shown in FIG. 3.

[0076] When the control flow shown in FIG. 6 is started, first, in step S201, the determination unit 112d of the control unit 112 determines whether a specific operation by the driver has been performed. The specific operation is an operation for adjusting the upper limit value of the time change rate of the motor torque. The driver performs the specific operation using, for example, the input device 43. For example, an operation of performing a setting operation (for example, an operation of pulling a paddle as the input device 43) again in a state where the brake control mode is set to the second brake mode corresponds to the specific operation. However, the specific operation may be an operation other than this example. Also, the specific operation may be performed in a state where the brake control mode is set to the first brake mode. Further, the specific operation may be performed during the execution of the brake control or when the brake control is not being executed.

[0077] If it is determined that the specific operation has not been performed (if it is determined NO in step S201), the control flow shown in FIG. 6 ends. On the other hand, if it is determined that the specific operation has been performed (if it is determined YES in step S201), the process proceeds to step S202.

[0078] If it is determined YES in step S201, in step S202, the setting unit 112c of the control unit 112 sets the upper limit value of the time change rate of the motor torque during an accelerator operation performed after the end of the second brake mode to a value larger than the normal upper limit value, and the control flow shown in FIG. 6 ends. The normal upper limit value is the upper limit value of the time change rate of the motor torque during an accelerator operation performed at timings other than after the end of the second brake mode. The control unit 112 controls the torque of the motor 21 so that the time change rate of the motor torque becomes equal to or less than the set value of the upper limit value of the time change rate.

[0079] As described above, when a specific operation by the driver is performed, the control unit 112 may increase the upper limit value of the time change rate of the motor torque during an accelerator operation performed after the end of the second braking mode, compared to the upper limit value of the time change rate of the motor torque during an accelerator operation performed at timings other than after the end of the second braking mode. The driver performs the specific operation when he / she wants to further improve the acceleration responsiveness during an accelerator operation performed after the end of the second braking mode. Therefore, during an accelerator operation performed after the end of the second braking mode, the acceleration responsiveness can be improved in accordance with the driver's intention.

[0080] Note that after the upper limit value of the time change rate of the motor torque is set to a value larger than the normal upper limit value, when a specific condition is satisfied, the setting unit 112c of the control unit 112 sets the upper limit value of the time change rate of the motor torque to the normal upper limit value. The specific condition may be, for example, that the accelerator operation performed after the end of the second braking mode is canceled, or that a predetermined operation by the driver is performed.

[0081] FIG. 7 is a flowchart showing an example of the flow of processing related to the setting of the driving force in the second braking mode performed by the control device 100 (that is, the driving force applied to the vehicle 1 by the motor 21 in the second braking mode). The control flow shown in FIG. 7 may be executed after the control flow shown in FIG. 3 ends, or may be executed by interrupting during the execution of the control flow shown in FIG. 3.

[0082] When the control flow shown in FIG. 7 is started, first, in step S301, the determination unit 112d of the control unit 112 determines whether the motor temperature is equal to or higher than the reference temperature. The reference temperature is, for example, an index for determining whether the motor 21 is at a high temperature to the extent that it is difficult to operate normally. The determination unit 112d determines whether the motor temperature is equal to or higher than the reference temperature based on, for example, the detection result of the motor temperature sensor 54.

[0083] When it is determined that the motor temperature is equal to or higher than the reference temperature (when the determination in step S301 is YES), the process proceeds to step S302. On the other hand, when it is determined that the motor temperature is lower than the reference temperature (when the determination in step S301 is NO), the process proceeds to step S303.

[0084] When the determination in step S301 is YES, in step S302, the setting unit 112c of the control unit 112 sets the driving force in the second brake mode to the second driving force, and the control flow shown in FIG. 7 ends. The second driving force is smaller than the first driving force, which will be described later. The second driving force is, for example, about several Nm.

[0085] When the determination in step S301 is NO, in step S303, the determination unit 112d of the control unit 112 determines whether or not the SOC of the battery 23 is equal to or lower than the reference SOC (that is, the reference remaining capacity). The reference SOC is, for example, an index for determining whether or not the electric power for driving the motor 21 is sufficiently stored in the battery 23. The determination unit 112d determines whether or not the SOC of the battery 23 is equal to or lower than the reference SOC based on, for example, the detection result of the battery sensor 55.

[0086] When it is determined that the SOC of the battery 23 is equal to or lower than the reference SOC (when the determination in step S303 is YES), the process proceeds to step S302. On the other hand, when it is determined that the SOC of the battery 23 is greater than the reference SOC (when the determination in step S303 is NO), the process proceeds to step S304.

[0087] When the determination in step S303 is NO, in step S304, the setting unit 112c of the control unit 112 sets the driving force in the second brake mode to the first driving force, and the control flow shown in FIG. 7 ends. The first driving force is, for example, a driving force corresponding to the running resistance of the vehicle 1. The control unit 112 controls the driving force applied to the vehicle 1 by the motor 21 to be a set value in the second brake mode.

[0088] As described above, when the motor temperature is equal to or higher than the reference temperature, the control unit 112 may reduce the driving force applied to the vehicle 1 by the motor 21 in the second braking mode as compared to the case where the motor temperature is lower than the reference temperature. When the motor temperature is equal to or higher than the reference temperature, it can be determined that the motor 21 is at a high temperature to such an extent that it becomes difficult to operate normally. In such a case, by reducing the driving force in the second braking mode, it is possible to suppress a further increase in the motor temperature.

[0089] Also, as described above, when the SOC of the battery 23 is equal to or lower than the reference SOC, the control unit 112 may reduce the driving force applied to the vehicle 1 by the motor 21 in the second braking mode as compared to the case where the SOC of the battery 23 is higher than the reference SOC. When the SOC of the battery 23 is equal to or lower than the reference SOC, it can be determined that the electric power for driving the motor 21 is not sufficiently stored in the battery 23. In such a case, by reducing the driving force in the second braking mode, it is possible to suppress an early depletion of the electric power of the battery 23.

[0090] Note that, as described above, even when the motor temperature is equal to or higher than the reference temperature or the SOC of the battery 23 is equal to or lower than the reference SOC, although the driving force in the second braking mode becomes small (for example, about several Nm), a driving force is applied to the vehicle 1 by the motor 21 in the second braking mode. Therefore, at the time of re-acceleration of the vehicle 1 after the end of the second braking mode, it is possible to suppress the occurrence of backlash in the power transmission system 12 and the like, and to suppress a reversal of the direction of the motor torque.

[0091] FIG. 8 is a flowchart showing an example different from the example of FIG. 7 of the flow of processing related to the setting of the driving force in the second braking mode (that is, the driving force applied to the vehicle 1 by the motor 21 in the second braking mode) performed by the control device 100. The control flow shown in FIG. 8 may be executed after the control flow shown in FIG. 3 ends, or may be executed by interrupting during the execution of the control flow shown in FIG. 3.

[0092] When the control flow shown in FIG. 8 starts, first, in step S401, the determination unit 112d of the control unit 112 determines whether the motor temperature is equal to or higher than the reference temperature. The process of step S401 is the same as the process of step S301 in the flowchart of FIG. 7 described above.

[0093] If it is determined that the motor temperature is equal to or higher than the reference temperature (when the determination in step S401 is YES), the process proceeds to step S402. On the other hand, if it is determined that the motor temperature is lower than the reference temperature (when the determination in step S401 is NO), the process proceeds to step S404.

[0094] When the determination in step S401 is YES, in step S402, the setting unit 112c of the control unit 112 permits the second brake mode. Next, in step S403, the setting unit 112c of the control unit 112 sets the driving force of the second brake mode to the second driving force, and the control flow shown in FIG. 8 ends. The second driving force in step S403 is the same as the second driving force in step S302 in the flowchart of FIG. 7 described above.

[0095] When the determination in step S401 is NO, in step S404, the determination unit 112d of the control unit 112 determines whether the SOC of the battery 23 is equal to or lower than the reference SOC. The process of step S404 is the same as the process of step S303 in the flowchart of FIG. 7 described above.

[0096] If it is determined that the SOC of the battery 23 is equal to or lower than the reference SOC (when the determination in step S404 is YES), the process proceeds to step S405. On the other hand, if it is determined that the SOC of the battery 23 is greater than the reference SOC (when the determination in step S404 is NO), the process proceeds to step S406.

[0097] When the determination in step S404 is YES, in step S405, the setting unit 112c of the control unit 112 prohibits the second brake mode, and the control flow shown in FIG. 8 ends.

[0098] When it is determined as NO in step S404, in step S406, the setting unit 112c of the control unit 112 permits the second brake mode. Next, in step S407, the setting unit 112c of the control unit 112 sets the driving force of the second brake mode to the first driving force, and the control flow shown in FIG. 8 ends. The first driving force in step S407 is the same as the first driving force in step S304 in the flowchart of FIG. 7 described above.

[0099] As described above, when the SOC of the battery 23 is less than or equal to the reference SOC, the control unit 112 may prohibit the second brake mode. As described above, when the SOC of the battery 23 is less than or equal to the reference SOC, it can be determined that the power for driving the motor 21 is not sufficiently stored in the battery 23. In such a case, by prohibiting the second brake mode and setting the first brake mode to be executed as the brake control, the motor 21 can be made to generate electricity to charge the battery 23. Therefore, the SOC of the battery 23 can be restored early.

[0100] In the above, an example in which the brake control mode is switched between the first brake mode and the second brake mode in response to a setting operation by the driver has been described. In this example, the brake control mode can be switched according to the driver's intention. That is, the acceleration responsiveness can be improved according to the driver's intention. However, the control unit 112 may automatically switch the brake control mode regardless of the setting operation by the driver. For example, the control unit 112 determines whether the driver desires an improvement in acceleration responsiveness based on information regarding the driving state of the vehicle 1 (for example, the acceleration of the vehicle 1 or the lateral acceleration occurring in the vehicle 1). Then, when the control unit 112 determines that the driver desires an improvement in acceleration responsiveness, the control unit 112 may switch the brake control mode to the second brake mode.

[0101] Also, in the above description, an example was described in which when an accelerator operation is started after the end of the second braking mode, the braking control mode is switched from the second braking mode to the first braking mode. In this example, each time the second braking mode ends, the braking control mode is switched to the first braking mode. However, when a predetermined operation by the driver is performed while the braking control mode is set to the second braking mode, the control unit 112 may switch the braking control mode to the first braking mode. In this case, if a next braking operation is performed without performing a predetermined operation after the end of the second braking mode, the second braking mode is executed again. Note that a mode in which the braking control mode is switched to the first braking mode triggered by an accelerator operation and a mode in which the braking control mode is switched to the first braking mode triggered by a predetermined operation by the driver may be selectable.

[0102] <Effect of the control device> Subsequently, the effect of the control device 100 according to the embodiment of the present invention will be described.

[0103] In the control device 100 according to the present embodiment, the control unit 112 switches the braking control mode between the first braking mode and the second braking mode. The first braking mode is a mode in which the braking device 31 operates while the regenerative braking force is applied to the vehicle 1 by the motor 21. The second braking mode is a mode in which the braking device 31 operates so that the braking force applied to the vehicle 1 by the braking device 31 becomes larger than that in the first braking mode while the driving force is applied to the vehicle 1 by the motor 21. Therefore, in the present embodiment, by setting the braking control mode to the second braking mode, it is possible to suppress the reversal of the direction of the motor torque when accelerating the vehicle 1 after braking. Thus, it is possible to suppress the time change rate of the motor torque from being restricted. Therefore, the acceleration responsiveness can be improved.

[0104] Further, in the control device 100 according to the present embodiment, it is preferable that the control unit 112 applies a driving force corresponding to the running resistance of the vehicle 1 to the vehicle 1 by the motor 21 during the execution of the second brake mode. Thereby, it is possible to suppress sudden acceleration during re-acceleration of the vehicle 1 after the end of the second brake mode, and effectively improve the acceleration responsiveness.

[0105] Further, in the control device 100 according to the present embodiment, when the brake operation is released during the execution of the second brake mode, the control unit 112 ends the second brake mode and continues to apply the driving force of the motor 21 to the vehicle 1 until the accelerator operation is started. Thereby, when accelerating the vehicle 1 after braking, it is possible to more appropriately suppress the reversal of the direction of the motor torque. Therefore, it is possible to more appropriately suppress the limitation of the time change rate of the motor torque. Accordingly, the acceleration responsiveness can be more appropriately improved.

[0106] Further, in the control device 100 according to the present embodiment, when a specific operation by the driver is performed, the control unit 112 increases the upper limit value of the time change rate of the motor torque during the accelerator operation by the driver after the end of the second brake mode, compared with the upper limit value during the accelerator operation by the driver at timing other than after the end of the second brake mode. Thereby, during the accelerator operation performed after the end of the second brake mode, the acceleration responsiveness can be improved in accordance with the driver's intention.

[0107] Further, in the control device 100 according to the present embodiment, when the motor temperature is equal to or higher than the reference temperature, it is preferable that the control unit 112 makes the driving force applied to the vehicle 1 by the motor 21 in the second brake mode smaller than when the motor temperature is lower than the reference temperature. Thereby, when the motor 21 is at a high temperature to the extent that it is difficult to operate normally, it is possible to suppress the further increase in the motor temperature.

[0108] Further, in the control device 100 according to the present embodiment, when the SOC of the battery 23 is less than or equal to the reference SOC, it is preferable that the control unit 112 reduces the driving force applied to the vehicle 1 by the motor 21 in the second braking mode as compared with the case where the SOC of the battery 23 is greater than the reference SOC. Thereby, when the electric power for driving the motor 21 is not sufficiently stored in the battery 23, it is possible to suppress the early depletion of the electric power of the battery 23.

[0109] Further, in the control device 100 according to the present embodiment, when the SOC of the battery 23 is less than or equal to the reference SOC, it is preferable that the control unit 112 prohibits the second braking mode. Thereby, when the electric power for driving the motor 21 is not sufficiently stored in the battery 23, it is possible to recover the SOC of the battery 23 at an early stage.

[0110] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications or corrections within the scope described in the claims also belong to the technical scope of the present invention.

[0111] For example, the processes described using flowcharts in this specification do not necessarily have to be executed in the order shown in the flowcharts. Also, additional processing steps may be adopted, and some processing steps may be omitted.

Explanation of Reference Numerals

[0112] 1 Vehicle 11 Wheels 12 Power Transmission System 21 Motor 22 Inverter 23 Battery 31 Brake Device 32 Hydraulic Control Unit 33 Master Cylinder 41 Accelerator Pedal 42 Brake Pedal 43 Input Device 51 Accelerator opening sensor 52 Brake sensor 53 Vehicle speed sensor 54 Motor temperature sensor 55 Battery sensor 100 Control device 101 Processor 102 Memory 111 Acquisition unit 112 Control unit 112a Motor control unit 112b Brake control unit 112c Setting unit 112d Judgment unit

Claims

1. A control device for a vehicle including a braking device and a motor as a drive source, one or more processors, one or more memories connected to the processor, having, the processor executes a process including switching between a first braking mode and a second braking mode for a braking control mode that is executed when the vehicle is braked in response to a braking operation by a driver's brake pedal, the first braking mode is a mode in which the braking device operates while a regenerative braking force is applied to the vehicle by the motor, the second braking mode is a mode in which the braking device operates such that a braking force applied to the vehicle by the braking device becomes greater than that in the first braking mode while a driving force is applied to the vehicle by the motor, the processor, when the braking control mode is set to the first braking mode, when the braking operation is performed, execute the first braking mode, in the first braking mode, control the motor and the braking device so that a required braking force corresponding to an operation amount of the braking operation is applied to the vehicle, when the braking control mode is set to the second braking mode, when the braking operation is performed, execute the second braking mode, in the second braking mode, control the motor and the braking device so that the required braking force is applied to the vehicle, when the braking control mode is set to the second braking mode, if the braking operation is released during execution of the second braking mode, end the second braking mode and continue applying the driving force to the vehicle by the motor until an accelerator operation by the driver is started, executing a process including, a control device.

2. The processor executes a process including applying, by the motor, a driving force corresponding to a running resistance of the vehicle to the vehicle during execution of the second braking mode, The control device according to claim 1.

3. When a specific operation by the driver is performed, the processor executes a process including making the upper limit value of the rate of change of the torque of the motor with respect to time during an accelerator operation by the driver performed after the end of the second braking mode larger than the upper limit value during an accelerator operation by the driver performed at a timing other than after the end of the second braking mode. The control device according to claim 1 or 2.

4. When the temperature of the motor is equal to or higher than a reference temperature, the processor executes a process including making the driving force applied to the vehicle by the motor in the second braking mode smaller than that when the temperature of the motor is lower than the reference temperature. The control device according to any one of claims 1 to 3.

5. The vehicle includes a battery connected to the motor. When the remaining capacity of the battery is equal to or less than a reference remaining capacity, the processor executes a process including making the driving force applied to the vehicle by the motor in the second braking mode smaller than that when the remaining capacity of the battery is larger than the reference remaining capacity. The control device according to any one of claims 1 to 4.

6. The vehicle includes a battery connected to the motor. When the remaining capacity of the battery is equal to or less than a reference remaining capacity, the processor executes a process including prohibiting the second braking mode. The control device according to any one of claims 1 to 4.

7. A control device for a vehicle including a braking device and a motor as a drive source, The control device includes a control unit that switches between a first braking mode and a second braking mode, which is a control for braking the vehicle in response to a braking operation by the driver's brake pedal and is executed when the braking operation is being performed. The first braking mode is a mode in which the braking device operates while a regenerative braking force is applied to the vehicle by the motor. The second braking mode is a mode in which the braking device operates such that the braking force applied to the vehicle by the braking device is larger than that in the first braking mode while a driving force is applied to the vehicle by the motor. The control unit When the mode of the brake control is set to the first brake mode, when the brake operation is performed, the first brake mode is executed, In the first brake mode, the motor and the brake device are controlled so that a required braking force corresponding to the operation amount of the brake operation is applied to the vehicle, When the mode of the brake control is set to the second brake mode, when the brake operation is performed, the second brake mode is executed, In the second brake mode, the motor and the brake device are controlled so that the required braking force is applied to the vehicle, When the mode of the brake control is set to the second brake mode, if the brake operation is released during the execution of the second brake mode, the second brake mode is terminated, and the application of the driving force to the vehicle by the motor is continued until the accelerator operation by the driver is started, Control device.

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