control device

Abstract

In a vehicle driven by an electric motor, if the vehicle speed exceeds the upper speed limit, it will be quickly decelerated to within the upper speed limit. [Solution] A hybrid ECU 10 applied to a vehicle 1 capable of driving and regenerative braking by a motor 2, which controls the motor 2 with a set target regenerative force, comprising: a vehicle speed acquisition unit 11 that acquires the vehicle speed V of the vehicle 1; an upper limit speed acquisition unit 12 that acquires the upper limit speed Vu of the road on which the vehicle 1 travels; and a regenerative force setting unit 13 that increases the target regenerative force when the vehicle speed V exceeds the upper limit speed Vu.

Description

Technical Field

[0001] The present invention relates to a control device for an electric vehicle.

Background Art

[0002] In electric vehicles that can be driven by an electric motor, such as electric cars, hybrid cars, and plug-in hybrid cars, regenerative power generation is generally performed by the electric motor during deceleration of the vehicle in order to suppress power consumption. By this regenerative power generation, power is recovered to the battery and regenerative braking force is applied to the vehicle.

[0003] For example, in Patent Document 1, there is disclosed a conventional technique in which the position of the host vehicle is acquired, and when it is determined that the host vehicle is located in an accident-prone environment, the regenerative force of the motor is made to act stronger than usual by using the regenerative braking force as described above.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when the traveling speed (vehicle speed) of the vehicle exceeds the upper limit speed of the road, it is necessary to decelerate the vehicle speed within the upper limit speed regardless of whether the position of the host vehicle is an accident-prone environment.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a control device for an electric vehicle that can quickly decelerate within the upper limit speed when the vehicle speed exceeds the upper limit speed in a vehicle driven by a motor.

Means for Solving the Problems

[0007] To achieve the above objective, the control device according to the present invention is applied to a vehicle capable of driving and regenerative braking by a motor, and is a control device that controls the motor with a set target regenerative force, comprising: a vehicle speed acquisition unit that acquires the driving speed of the vehicle; an upper speed limit acquisition unit that acquires the upper speed limit of the road on which the vehicle is traveling; and a regenerative force setting unit that increases the target regenerative force when the driving speed exceeds the upper speed limit. [Effects of the Invention]

[0008] The control device of the present invention acquires the vehicle's travel speed and the upper speed limit of the road on which the vehicle is traveling, and if the travel speed exceeds the upper speed limit, it controls the motor to increase its target regenerative force. As a result, the regenerative braking force when the accelerator is released from the vehicle is stronger than usual. Therefore, according to the electric vehicle control device of the present invention, in a vehicle driven by an electric motor, if the vehicle speed exceeds the upper speed limit, it can be quickly decelerated to within the upper speed limit. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram relating to regenerative braking control of a vehicle to which the control device described herein is applied. [Figure 2] This is an example of a regenerative braking level controlled by paddle shifters. [Figure 3] This flowchart shows the procedure for setting the target regenerative force during regenerative braking. [Modes for carrying out the invention]

[0010] The embodiments will now be described in detail with reference to the drawings. Figure 1 is a block diagram relating to regenerative braking control of a vehicle 1 to which the control device according to this disclosure is applied. Vehicle 1 is a plug-in hybrid vehicle (PHEV) or hybrid vehicle (hereinafter referred to as a hybrid vehicle) that can be charged from an external source and can supply power to an external source, and its main components related to regenerative braking control include a motor 2, an MCU 3, a battery 4, a BMU 5, a vehicle system ECU 6, a braking device 7, an ADAS-ECU 8, a paddle shift 9, and a hybrid ECU 10 as a "control device". In addition to the above configuration, vehicle 1 is also equipped with various components that are known to be installed in hybrid vehicles, such as an engine (internal combustion engine) which is not shown. Furthermore, vehicle 1 may be an electric vehicle (pure EV) that does not have an engine (internal combustion engine).

[0011] Motor 2 is a so-called motor generator that can provide power to drive vehicle 1 when electricity is supplied, and can also generate electricity by regenerating power when vehicle 1 is decelerating.

[0012] The MCU3 is an electronic control unit that exchanges power with the motor 2. It converts the DC power supplied from the battery 4 into AC power and outputs it to the motor 2, and converts the AC power regenerated from the motor 2 into DC power to charge the battery 4. The MCU3 also controls the operation of the motor drive and regenerative drive by controlling the motor torque of the motor 2.

[0013] Battery 4 is a lithium-ion battery that primarily outputs power used for driving vehicle 1 and can be charged by regenerative power from motor 2. In this embodiment, it is configured as a battery pack that integrates a voltage sensor Sv, a current sensor Sc, and a temperature sensor St. The voltage sensor Sv, current sensor Sc, and temperature sensor St measure the voltage, current, and temperature of battery 4 itself, respectively.

[0014] The BMU5 is an electronic control unit that performs State of Charge (SOC) calculations and manages the state of the battery 4 by obtaining the voltage, current, and temperature of the battery 4 as described above.

[0015] The vehicle system ECU 6 is an electronic control unit for controlling the vehicle body, such as the engine (not shown) and braking system 7, and acquires the vehicle speed (vehicle speed) of the vehicle 1 measured by the vehicle speed sensor Ss.

[0016] The braking device 7 is, for example, a friction brake provided on the wheels of the vehicle 1, and is a known deceleration device that is mainly operated by the driver of the vehicle 1 using the foot brake. In this embodiment, as will be described later, the braking device 7 is configured to decelerate the vehicle 1 by being driven and controlled from the hybrid ECU 10 via the vehicle system ECU 6 when the regenerative braking force of the motor 2 is insufficient.

[0017] The ADAS-ECU8 is an electronic control unit for performing various preventative safety support functions such as following the vehicle in front and lane keeping assist. In this embodiment in particular, it estimates the maximum speed of the driving route from information acquired from the camera C and navigation system N mounted on the vehicle 1.

[0018] The paddle shift 9 is a regenerative braking control unit that allows the driver to select the regenerative braking force during regenerative braking of the motor 2, as will be described in detail later. In this embodiment, it is provided on the steering wheel W of the vehicle 1 as a regenerative braking force increase button 9(+) and a regenerative braking force decrease button 9(-). Note that the regenerative braking control unit is not limited to the paddle shift 9, but may be a shift lever or other types of push buttons.

[0019] The hybrid ECU 10, acting as a "control device," is an electronic control unit that controls the entire vehicle 1 by transmitting and receiving information with each component of the vehicle 1. It consists of input / output devices, memory devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), timers, etc.

[0020] More specifically, the hybrid ECU 10 acquires the state of the battery 4 via the BMU 5 and acquires the vehicle speed of the vehicle 1 via the vehicle system ECU 6. Further, the hybrid ECU 10 controls, via the MCU 3, the discharge control from the battery 4 to the motor 2 in power running control and the charge control from the battery 4 to the motor 2 in regenerative control. At this time, the hybrid ECU 10 acquires the driver's regenerative force operation via the paddle shift 9, sets the target value of the regenerative braking force for the motor 2, that is, the target regenerative force, and controls the regenerative torque of the motor 2 with the target regenerative force.

[0021] In addition, the hybrid ECU 10 according to the present embodiment particularly includes a vehicle speed acquisition unit 11, an upper limit speed acquisition unit 12, a regenerative force setting unit 13, and a braking control unit 14 as function modules related to regenerative braking. Further, as will be described in detail later, when the vehicle speed V of the vehicle 1 exceeds the upper limit speed Vu of the road, the hybrid ECU 10 performs control to increase the regenerative braking force of the motor 2 during deceleration and quickly reduce the vehicle speed V within the upper limit speed Vu.

[0022] The vehicle speed acquisition unit 11 acquires the vehicle speed V measured by the vehicle speed sensor Ss via the vehicle system ECU 6. The upper limit speed acquisition unit 12 acquires the upper limit speed Vu of the road estimated by the ADAS-ECU 8. The regenerative force setting unit 13 sets the regenerative braking force of the motor 2 based on the operation of the paddle shift 9, instructs the MCU 3 to perform motor torque control during regenerative control, and performs control to increase the above-described target regenerative force when the vehicle speed V exceeds the upper limit speed Vu. The braking control unit 14 performs control to drive the braking device 7 via the vehicle system ECU 6 when the deviation between the vehicle speed V and the upper limit speed Vu is large and the regenerative braking force of the motor 2 alone is insufficient.

[0023] FIG. 2 shows an example of the regeneration level operated by paddle shift 9. The regenerative braking force of motor 2 is set to six levels of regenerative levels, for example, B0 to B5, depending on its magnitude. The regenerative braking force of B0 is 0, and the regenerative braking force is set to be in the order of B0 < B1 < B2 < B3 < B4 < B5. When the driver puts the shift lever of vehicle 1 into the drive range (D), the regenerative level B2 is set. Also, at this time, if the driver presses the regenerative force increase button 9(+) of paddle shift 9, for example, once, it is switched to the regenerative level B3. That is, the driver can select the magnitude of the regenerative braking force by paddle shift 9 according to his / her preference and can store it as the standard regenerative force unless a new change operation is performed.

[0024] Also, the driver can confirm which regenerative level is set by the display in the driver's seat of vehicle 1. Note that the regenerative braking force of motor 2 may be adjusted more finely than the above six levels, and as described later, the regenerative force setting unit 13 may continuously change the regenerative braking force according to the driving state of vehicle 1.

[0025] By the way, when the vehicle speed V of vehicle 1 exceeds the upper limit speed Vu of the road, it is necessary to decelerate the vehicle speed V of vehicle 1 within the upper limit speed Vu. For this reason, the hybrid ECU 10 according to the present embodiment performs control to quickly decelerate vehicle 1 within the upper limit speed Vu by increasing the regenerative braking force of motor 2 according to the procedure described below in such a case.

[0026] FIG. 3 is a flowchart showing the procedure for setting the target regenerative force during regenerative braking. The hybrid ECU 10 performs control to change the target regenerative force as necessary by repeatedly executing the procedure shown in FIG. 3 while vehicle 1 is being driven.

[0027] When this procedure is initiated, the hybrid ECU 10 acquires the regenerative braking level selected by the driver via the paddle shift 9 as described above and stores it as the standard regenerative braking force (step S1). Here, the standard regenerative braking force is assumed to be, for example, the initial setting, regenerative braking level B2.

[0028] Next, the hybrid ECU 10 acquires the constantly changing vehicle speed V from the vehicle speed sensor Ss in the vehicle speed acquisition unit 11 (step S2), and acquires the road's upper speed limit Vu estimated by the ADAS-ECU 8 in the upper speed limit acquisition unit 12 (step S3). Subsequently, the hybrid ECU 10 determines whether the vehicle speed V exceeds the upper speed limit Vu (step S4).

[0029] When the hybrid ECU 10 determines that the vehicle speed V exceeds the upper limit speed Vu (Yes in step S4), it determines whether the driver is operating the accelerator (step S5). At this time, the regenerative force setting unit 13 controls the target regenerative force to increase according to the difference De (=V-Vu) between the vehicle speed V and the upper limit speed Vu (step S6). More specifically, if the difference De is relatively small, the regenerative force setting unit 13 sets the target regenerative force to a regenerative braking force that is about halfway between regenerative level B2 and regenerative level B3, and if the difference De is relatively high, it sets the target regenerative force to regenerative level B3.

[0030] Furthermore, the method of increasing the target regenerative force is not limited to control based on the deviation De as in step S6. For example, the regenerative force setting unit 13 may calculate the deviation De based on the vehicle speed V and the upper limit speed Vu, and then calculate the ratio R of the deviation De to the upper limit speed Vu (=De / Vu=(V-Vu) / Vu), and increase the target regenerative force as the ratio R increases. As the ratio R increases, it becomes necessary to decelerate the vehicle 1 to the upper limit speed Vu as quickly as possible, so the regenerative force setting unit 13 can effectively apply regenerative braking force by using the ratio R as an indicator.

[0031] Here, the hybrid ECU 10 may determine whether the required braking force of the vehicle 1, which is determined according to the difference De between the vehicle speed V and the upper limit speed Vu, exceeds the regenerative braking force of the motor 2. If the braking control unit 14 determines that the required braking force exceeds the regenerative braking force, it drives the braking device 7 via the vehicle system ECU to compensate for the insufficient braking force. As a result, the hybrid ECU 10 enables the motor 2 and the braking device 7 to work together to reduce the vehicle speed V to within the upper limit speed Vu.

[0032] Furthermore, the hybrid ECU 10 sets an upper limit for the target regenerative force according to the state of the battery 4 and limits the increase in the target regenerative force as necessary (step S7). That is, the regenerative force setting unit 13 obtains the voltage of the battery 4 measured by the voltage sensor Sv via the BMU 5 and calculates the strength of the regenerative braking force that would cause the battery 4 to overcharge during regenerative charging as an upper limit. Therefore, if the set target regenerative force exceeds the upper limit, the battery 4 is protected from overcharging by setting the target regenerative force to that upper limit. Note that the parameters related to the charge state are not limited to the voltage of the battery 4, but may also be the State of Charge calculated by the BMU 5.

[0033] The hybrid ECU 10 then determines whether or not regenerative torque has been generated by motor 2 due to the release of the driver's accelerator operation (step S8). If the hybrid ECU 10 determines that the accelerator operation has been released, it performs regenerative braking with the set target torque, decelerating vehicle 1 with a regenerative braking force stronger than the standard regenerative force. In addition, the hybrid ECU 10 maintains the set target torque for regenerative braking until the accelerator operation is released (No in step S8).

[0034] Furthermore, the regenerative force setting unit 13 may measure the duration of the state in which the vehicle speed V exceeds the upper limit speed Vu, and control the system to continuously or gradually increase the target regenerative force as the duration of this state increases. In this case, the longer the vehicle speed V exceeds the upper limit speed Vu, the stronger the regenerative braking force will be when the vehicle 1 decelerates, thus effectively making the driver aware of this situation.

[0035] Furthermore, when the accelerator operation is released (No in step S5, or Yes in step S8), the hybrid ECU 10 determines whether the vehicle speed V exceeds the upper limit speed Vu again (step S4). If the hybrid ECU 10 determines that the accelerator operation is being performed again despite the vehicle speed V still exceeding the upper limit speed Vu (Yes in step S4, Yes in step S5), it performs control to further increase the target regenerative force (step S6). In other words, when the vehicle speed V exceeds the upper limit speed Vu, the regenerative force setting unit 13 increases the target regenerative force each time the accelerator is operated, thereby increasing the regenerative braking force when the accelerator is released, quickly decelerating the vehicle 1, and effectively making the driver aware of this state.

[0036] On the other hand, if the regenerative force setting unit 13 determines that the vehicle speed V does not exceed the upper limit speed Vu, or that the vehicle speed V falls below the upper limit speed Vu due to deceleration (No in step S4), it controls the target regenerative force to return to the regenerative level selected by the driver, i.e., the standard regenerative level (step S9). As a result, when the vehicle speed V is below the upper limit speed Vu, regenerative braking force can be applied to the vehicle 1 during deceleration without causing discomfort to the driver.

[0037] As described above, the hybrid ECU 10 according to this disclosure acquires the vehicle speed V of the vehicle 1 and the upper speed limit Vu of the road on which the vehicle 1 is traveling, and controls the motor 2 to increase its target regenerative force when the vehicle speed V exceeds the upper speed limit Vu. As a result, the regenerative braking force of the vehicle 1 acts more strongly than usual when the accelerator operation is released. Therefore, with the hybrid ECU 10 of the electric vehicle according to this disclosure, the vehicle 1 driven by the motor 2 can be quickly decelerated to within the upper speed limit Vu when the vehicle speed V exceeds the upper speed limit Vu.

[0038] Furthermore, the hybrid ECU 10 measures the duration of the state in which the vehicle speed V exceeds the upper speed Vu, and increases the target regenerative force as the duration of this state increases. This allows for stronger regenerative braking force to be applied when the vehicle 1 decelerates the longer the speed exceeding state persists, and also effectively makes the driver aware of this situation.

[0039] Furthermore, when the vehicle speed V exceeds the upper speed Vu, the hybrid ECU 10 increases the target regenerative force each time the accelerator is pressed, thereby increasing the regenerative braking force when the accelerator is released, quickly decelerating the vehicle 1, and effectively making the driver aware of this state.

[0040] Furthermore, when the vehicle speed V falls below the upper limit speed Vu, the hybrid ECU 10 resets the target regenerative force to a predetermined target regenerative force. This prevents the increased regenerative braking force from extending to driving within the upper limit speed Vu, thus allowing regenerative braking force to be applied to the driver during deceleration of the vehicle 1 without causing discomfort.

[0041] Furthermore, the hybrid ECU 10 acquires the regenerative braking level selected by the driver via the paddle shift 9 and stores it as the standard regenerative force, allowing the driver to set the regenerative braking force within the upper speed limit Vu according to their preference.

[0042] Furthermore, the hybrid ECU 10 controls the vehicle to increase the target regenerative force in accordance with the difference De (=V-Vu) between the vehicle speed V and the upper limit speed Vu, thereby enabling the vehicle speed V to be reduced to within the upper limit speed Vu more quickly.

[0043] Furthermore, the hybrid ECU 10 calculates the deviation De based on the vehicle speed V and the upper speed Vu, and increases the target regenerative force as the ratio R (=D / Vu=(V-Vu) / Vu) of the deviation De relative to the upper speed Vu increases. This allows for the application of stronger regenerative braking force more effectively when it is necessary to decelerate vehicle 1 urgently.

[0044] Furthermore, when the required braking force of the vehicle 1, which is determined according to the above-mentioned discrepancy De, exceeds the regenerative braking force of the motor 2, the hybrid ECU 10 drives the braking device 7 to compensate for the insufficient braking force, thereby enabling the motor 2 and the braking device 7 to work together to reduce the vehicle speed V to within the upper limit speed Vu.

[0045] Furthermore, the hybrid ECU 10 can prevent overcharging of the battery 4 by setting an upper limit for the target regenerative force according to parameters related to the charging of the battery 4 that supplies power to the motor 2. [Explanation of symbols]

[0046] 1 vehicle 2 motors 4 Batteries 7 Braking device 9 paddle shifters 9(+) Regenerative Power Increase Button 9(-) Regenerative braking reduction button 10 Hybrid ECU 11 Vehicle speed acquisition part 12 Upper limit speed acquisition section 13th Generation Student Development Department 14 Brake Control Unit

Claims

1. A control device applied to a vehicle capable of driving and regenerative braking by a motor, which controls the motor with a set target regenerative force, A vehicle speed acquisition unit that acquires the vehicle's travel speed, A speed limit acquisition unit that acquires the speed limit of the road on which the vehicle is traveling, A control device comprising: a regenerative force setting unit that increases the target regenerative force when the aforementioned driving speed exceeds the aforementioned upper speed limit.

2. The control device according to claim 1, wherein the regenerative force setting unit measures the duration of the state in which the driving speed exceeds the upper limit speed, and increases the target regenerative force as the duration increases.

3. The control device according to claim 1 or 2, wherein the regenerative force setting unit increases the target regenerative force each time the vehicle's accelerator is operated while the driving speed exceeds the upper limit speed.

4. The control device according to claim 1 or 2, wherein the regenerative force setting unit resets the target regenerative force to a predetermined standard regenerative force when the driving speed falls below the upper limit speed.

5. A control device according to claim 4, which is applied to a vehicle having a regenerative force operation unit for adjusting the regenerative braking force of the motor, The standard regenerative force is selected by the operation of the regenerative force control unit, and this is a control device.

6. The control device according to claim 1 or 2, wherein the regenerative force setting unit increases the target regenerative force as the difference between the driving speed and the upper limit speed increases.

7. The control device according to claim 1 or 2, wherein the regenerative force setting unit calculates the difference between the driving speed and the upper limit speed, and increases the target regenerative force as the ratio of the difference to the upper limit speed increases.

8. A control device according to claim 1 or 2, applicable to the vehicle having a braking device, A control device comprising a braking control unit that drives the braking device to compensate for insufficient braking force when the required braking force of the vehicle, which is determined according to the difference between the aforementioned driving speed and the aforementioned upper speed, exceeds the regenerative braking force of the motor.

9. The control device according to claim 1 or 2, wherein the regenerative force setting unit acquires parameters relating to the charge state of the battery that supplies power to the motor, and sets an upper limit of the target regenerative force so that the battery does not become overcharged according to the parameters.

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