JP2012131306A - Brake control device of electric motor vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the prevention of control interference, frequency restraint of control reintervention and effectiveness of securing a regenerative energy quantity, when ABS control intervenes in regenerative cooperative brake control.SOLUTION: This brake control device of a hybrid vehicle includes a brake liquid pressure generating device 1 being a hydraulic braking means, a motor controller 8 being a regenerative quantity control means, an integrated controller 9 being a regenerative cooperative brake control means, and a brake controller 7 being an ABS control means. The integrated controller 9 performs the regenerative cooperative brake control in ABS intervention for returning to the regenerative cooperative brake control by a limited regenerative braking request with a regenerative quantity limited to a value of not exceeding a regenerative quantity in ABS control intervention of the last time as a regenerative quantity limiter of this time, when the ABS control transfers to a nonoperation state, by stopping the regenerative braking request in ABS control intervention, when the ABS control intervenes in the regenerative cooperative brake control (Fig.3).

Description

  The present invention relates to a brake control device for an electric vehicle that is applied to an electric vehicle such as a hybrid vehicle or an electric vehicle and that has anti-lock brake control (= ABS control) intervention during regenerative cooperative brake control.

  Conventionally, the braking force control device prohibits the generation of regenerative braking force by the regenerative braking means when ABS control for preventing wheel lock is executed. And after ABS control is complete | finished during brake operation, what prohibits generation | occurrence | production of the regenerative braking force during the brake operation is known (for example, refer patent document 1).

Japanese Patent No. 3541646

  However, in the conventional braking force control device, when the ABS control is once activated during one brake operation, the regenerative cooperative brake control is prohibited from the start of the ABS control to the end of the brake operation in the braking operation. . For this reason, for example, during low μ road braking where the ABS control operation frequency is high, the amount of regenerative energy due to regenerative braking will be kept low. In this case, there was a problem that the utility electricity cost was lowered.

  The present invention has been made paying attention to the above problems, and when anti-lock brake control intervenes during regenerative cooperative brake control, it is effective to prevent control interference, reduce the frequency of control re-intervention, and ensure the amount of regenerative energy. It is an object of the present invention to provide a brake control device for an electric vehicle that can achieve the above.

In order to achieve the above object, a brake control device for an electric vehicle according to the present invention comprises a hydraulic braking means, a regeneration amount control means, a regeneration cooperative brake control means, an antilock brake control means, an ABS intervention regeneration cooperative brake. Control means and means provided.
The hydraulic braking means applies a brake hydraulic pressure to a wheel cylinder provided on each of the front and rear wheels during a brake operation.
The regenerative amount control means controls the regenerative amount in accordance with a command to a traveling electric motor connected to the drive wheel during a brake operation.
The regenerative cooperative brake control means performs control to achieve a braking target value as a sum of a hydraulic braking force based on the brake hydraulic pressure and a regenerative braking force based on the regenerative amount during a brake operation.
The anti-lock brake control means increases / decreases the brake fluid pressure to the wheel cylinder so as to suppress the brake lock according to a command to the brake fluid pressure actuator when the wheel is likely to be brake-locked during a brake operation.
The regenerative cooperative brake control means during the ABS intervention stops the regenerative braking request during the antilock brake control intervention when the antilock brake control intervenes during the regenerative cooperative brake control, and the antilock brake control is not activated. Is shifted to the regenerative cooperative brake control by the limited regenerative braking request with the regenerative amount limited to the value not exceeding the regenerative amount at the time of the previous anti-lock brake control intervention as the current regenerative amount upper limit value.

Therefore, when the antilock brake control intervenes during the regenerative cooperative brake control, the regenerative braking request is stopped during the antilock brake control intervention. For this reason, the control interference which has a bad influence by regenerative braking force with respect to the anti-lock brake control which suppresses braking lock by pressure reduction operation of brake fluid pressure is prevented.
Further, when returning to the regenerative cooperative brake control, the regenerative amount that is limited to a value that does not exceed the regenerative amount at the time of the previous antilock brake control intervention is set as the current regenerative amount upper limit value. That is, when an unrestricted regenerative braking request is made at the time of return, the return braking force for the regenerative wheel becomes excessive, which induces re-intervention of the antilock brake control and increases the frequency of re-intervention. On the other hand, the frequency of re-intervention of the antilock brake control can be suppressed by using the limited regenerative braking request.
And if anti-lock brake control transfers to a non-operation state, it will return to regenerative cooperation brake control. For this reason, the regenerative prohibition frequency is reduced compared to the case where the regenerative braking is prohibited even when the antilock brake control shifts to the non-operating state. In addition, since the re-intervention frequency of the antilock brake control is suppressed by the limited regenerative braking request, the restored regenerative cooperative brake control is continued, and the amount of regenerative energy by regenerative braking is effectively secured.
As a result, when antilock brake control intervenes during regenerative cooperative brake control, it is possible to achieve prevention of control interference, suppression of frequency of control re-intervention, and effective securing of the amount of regenerative energy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a brake system diagram illustrating a configuration of a hybrid vehicle by front wheel drive to which a brake control device according to a first embodiment is applied. It is a brake fluid pressure circuit diagram showing the VDC brake fluid pressure unit in the brake control device of Example 1. It is a flowchart which shows the structure and flow of a regenerative cooperation brake control process at the time of ABS intervention performed with the integrated controller in the brake control apparatus of Example 1. 5 is a time chart showing characteristics of vehicle body speed, wheel speed, ABS operation flag, and regenerative torque when ABS control intervenes during regenerative cooperative brake control in the brake control device of Comparative Example 1; 7 is a time chart showing characteristics of vehicle body speed, wheel speed, ABS operation flag, and regenerative torque when ABS control intervenes during regenerative cooperative brake control in the brake control device of Comparative Example 2. FIG. 4 is an operation explanatory diagram showing a regenerative cooperative brake control operation at the time of maximum regenerative torque generation in which a driver-requested deceleration is achieved by a sum of basic hydraulic pressure and regenerative components when a brake is operated in a hybrid vehicle equipped with the brake control device of Embodiment 1; is there. Regenerative coordination during ABS intervention that achieves deceleration by switching from the sum of basic fluid pressure and pressurization to the sum of basic fluid pressure and regeneration during braking in a hybrid vehicle equipped with the brake control device of Example 1 It is action explanatory drawing which shows a brake control action. 6 is a time chart showing characteristics of a vehicle body speed, a wheel speed, an ABS operation flag, and a regenerative torque when ABS control intervenes during regenerative cooperative brake control in the brake control device of the first embodiment.

  Hereinafter, the best mode for realizing a brake control device for an electric vehicle according to the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 shows the configuration of a hybrid vehicle that is an example of a front-wheel drive electric vehicle to which the brake control device of the first embodiment is applied, and FIG. 2 shows a VDC brake hydraulic unit that is an example of a brake hydraulic actuator. Hereinafter, based on FIG. 1 and FIG. 2, the structure of the regeneration cooperation brake system using VDC is demonstrated.

  As shown in FIG. 1, the brake deceleration generation system of the brake control device according to the first embodiment includes a brake hydraulic pressure generating device 1 (hydraulic braking means), a VDC brake hydraulic pressure unit 2 (brake hydraulic pressure actuator), A stroke sensor 3, a left front wheel wheel cylinder 4FL, a right front wheel wheel cylinder 4FR, a left rear wheel wheel cylinder 4RL, a right rear wheel wheel cylinder 4RR, and a traveling electric motor 5 are provided.

  In other words, a regenerative cooperative brake system using an existing VDC system (VDC stands for “Vehicle Dynamics Control”) is used. The VDC system is a system that performs vehicle behavior control (= VDC control) that prevents skidding and exhibits excellent running stability when the vehicle posture is disturbed due to corner entry at high speed or sudden steering operation. In VDC control, for example, if the turning behavior is sensed as being oversteered, the front wheel outside the corner is braked, and conversely if the turning behavior is sensed as being understeered, the driving power is reduced and the corners of the rear wheels are reduced. Brake the inner tire.

  The brake fluid pressure generating device 1 is basic fluid pressure generating means for generating a basic fluid pressure component corresponding to a brake operation by a driver among brake fluid pressures to the wheel cylinders 4FL, 4FR, 4RL, 4RR of each wheel. . As shown in FIGS. 1 and 2, the brake fluid pressure generating device 1 includes a brake pedal 11, a negative pressure booster 12, a master cylinder 13, and a reserve tank 14. That is, the driver's brake pedal force applied to the brake pedal 11 is boosted by the negative pressure booster 12, and the primary hydraulic pressure and the secondary hydraulic pressure by the master cylinder pressure are generated by the master cylinder 13. At this time, it is designed in advance so that the deceleration generated by the master cylinder pressure is smaller than the driver requested deceleration.

  The VDC brake fluid pressure unit 2 is interposed between the brake fluid pressure generator 1 and the wheel cylinders 4FL, 4FR, 4RL, 4RR of each wheel. The VDC brake fluid pressure unit 2 is a brake fluid pressure actuator that includes fluid pressure pumps 22 and 22 driven by a VDC motor 21 and controls pressure increase / hold / reduction of the master cylinder pressure. The VDC brake fluid pressure unit 2 and the brake fluid pressure generator 1 are connected by a primary fluid pressure pipe 61 and a secondary fluid pressure pipe 62. The VDC brake hydraulic unit 2 and the wheel cylinders 4FL, 4FR, 4RL, 4RR of each wheel are connected by a left front wheel hydraulic pipe 63, a right front wheel hydraulic pipe 64, a left rear wheel hydraulic pipe 65, and a right rear wheel hydraulic pipe 66. ing. In other words, when a pressure is required at the time of brake operation, the master cylinder pressure generated by the brake fluid pressure generator 1 is pressurized by the VDC brake fluid pressure unit 2 and the wheel cylinders 4FL, 4FR, 4RL of each wheel. , 4RR is added to obtain a hydraulic braking force.

  As shown in FIG. 2, the specific configuration of the VDC brake hydraulic unit 2 includes a VDC motor 21, hydraulic pumps 22 and 22 driven by the VDC motor 21, reservoirs 23 and 23, and a master cylinder pressure sensor 24. And having. Solenoid valves include a first M / C cut solenoid valve 25, a second M / C cut solenoid valve 26, holding solenoid valves 27, 27, 27, 27, and pressure reducing solenoid valves 28, 28, 28, 28. Have. The first M / C cut solenoid valve 25 and the second M / C cut solenoid valve 26 are differential pressure valves. When the VDC motor 21 is operated, the differential pressure between the wheel cylinder pressure (downstream pressure) and the master cylinder pressure (upstream pressure) is obtained. Control.

  The stroke sensor 3 is means for detecting a brake pedal operation amount by a driver with a potentiometer or the like. The stroke sensor 3 is a component added to an existing VDC system as a configuration for detecting a driver request deceleration that is necessary information in regenerative cooperative brake control.

  The wheel cylinders 4FL, 4FR, 4RL, 4RR are set on the brake discs of the front and rear wheels, and the hydraulic pressure from the VDC brake hydraulic pressure unit 2 is applied. Then, when hydraulic pressure is applied to each wheel cylinder 4FL, 4FR, 4RL, 4RR, a hydraulic braking force is applied to the front and rear wheels by clamping the brake disc with a brake pad.

  The travel electric motor 5 is provided as a travel drive source for the left and right front wheels (drive wheels) and has a drive motor function and a power generator function. The electric motor 5 for traveling transmits driving force to the left and right front wheels by driving the motor while consuming battery power during power running. During regeneration, the load is applied to the rotational drive of the left and right front wheels to convert it into electrical energy, and the generated power is charged to the battery. That is, the load applied to the rotational drive of the left and right front wheels is the regenerative braking force. The driving system for the left and right front wheels (drive wheels) provided with the traveling electric motor 5 is provided with an engine 10 as a traveling drive source in addition to the traveling electric motor 5, and is driven to the left and right front wheels via the transmission 11. Transmit power.

  As shown in FIG. 1, the brake deceleration control system of the brake control device according to the first embodiment includes a brake controller 7 (anti-lock brake control means), a motor controller 8 (regenerative braking force control means), and an integrated controller 9 ( Regenerative cooperative brake control means) and an engine controller 12.

  The brake controller 7 inputs a command from the integrated controller 9 and pressure information from the master cylinder pressure sensor 24 of the VDC brake hydraulic pressure unit 2. Then, a drive command is output to the VDC motor 21 and solenoid valves 25, 26, 27, 28 of the VDC brake hydraulic unit 2 according to a predetermined control law. The brake controller 7 controls the differential pressure between the wheel cylinder pressure (downstream pressure) and the master cylinder pressure (upstream pressure) when a pressure increase command is input from the integrated controller 9 during regenerative cooperative brake control. The differential pressure control is performed by differential pressure control based on operating current values to the first M / C cut solenoid valve 25 and the second M / C cut solenoid valve 26 and pump-up pressure increase by the VDC motor 21. The brake controller 7 performs the VDC control, TCS control, ABS control, and the like in addition to the regenerative cooperative brake control. ABS control is based on the command to the VDC brake fluid pressure unit 2 to brake the brake fluid pressure to the wheel cylinder of the wheel that is likely to be locked by reducing / holding / increasing the pressure when braking is applied. Control to suppress the lock. This ABS control is started when the difference between the estimated vehicle speed and the detected wheel speed exceeds the ABS intervention threshold at the time of the brake operation, and the difference between the vehicle speed and the wheel speed converges and the state below the ABS release threshold is reached. It ends when the set time continues.

  The motor controller 8 is connected to a traveling electric motor 5 connected to left and right front wheels, which are drive wheels, via an inverter 13. When the regenerative braking command is input from the integrated controller 9 during the regenerative cooperative brake control, the regenerative braking force control means controls the regenerative braking force generated by the traveling electric motor 5 according to the input regenerative braking command. The motor controller 8 also has a function of controlling the motor torque and the motor rotation speed generated by the traveling electric motor 5 according to the traveling state and the vehicle state during traveling.

  The integrated controller 9 achieves the driver's required deceleration at the time of brake operation by the sum of the basic hydraulic pressure due to the master cylinder pressure, the regeneration due to the regenerative braking force, and the pressurization due to the VDC brake hydraulic pressure unit 2. Perform regenerative cooperative brake control. At this time, the driver requested deceleration is determined based on the pedal stroke sensor value from the stroke sensor 3 and the set driver requested deceleration characteristic map. The integrated controller 9 includes battery charge capacity information from the battery controller 91, vehicle speed information from the vehicle speed sensor 92, brake operation information from the brake switch 93, brake pedal stroke information from the stroke sensor 3, and master cylinder pressure sensor 24. Master cylinder pressure information, etc. are input. As the vehicle speed sensor 92, a vehicle speed detection means capable of detecting a vehicle speed up to an extremely low vehicle speed range and also used for ABS control is used.

  FIG. 3 shows the configuration and flow of ABS intervention regenerative cooperative brake control processing executed by the integrated controller 8 in the brake control apparatus of Embodiment 1 (ABS intervention regenerative cooperative brake control means). Hereinafter, each step of FIG. 3 will be described.

  In step S1, the presence or absence of a brake operation is determined based on the switch signal from the brake switch 93. If YES (with brake operation), the process proceeds to step S2. If NO (without brake operation), the process proceeds to step S11.

  In step S2, it is determined whether or not the ABS control is inactive following the determination that the brake operation is performed in step S1. If YES (ABS not activated), the process proceeds to step S3, and if NO (ABS activated), the process proceeds to step S6.

  In step S3, following the determination that the ABS is not operating in step S2, it is determined whether or not a regeneration permission condition (regenerative braking force generation system, hydraulic braking force generation system, and communication are all normal) is satisfied. . If YES (regeneration permission condition is satisfied), the process proceeds to step S4. If NO (regeneration permission condition is not satisfied), the process proceeds to the end.

In step S4, following the determination that the regeneration permission condition is satisfied in step S3, the regeneration amount is determined by selecting the maximum regeneration amount, regeneration amount limiter (regeneration amount upper limit value), regeneration rate limiter, and executable regeneration amount. Then, the process proceeds to step S5.
Here, the “maximum regeneration amount” refers to the maximum value of the regeneration amount that is determined based on the vehicle speed range without being subjected to regeneration amount restriction conditions such as battery charge capacity, battery temperature, and motor temperature.
“Regenerative amount limiter” refers to the upper limit of the regenerative amount that is used in regenerative cooperative brake control that is restored when the ABS operation is not performed next time when ABS control intervenes during regenerative cooperative brake control. It is set to a value that does not exceed the regenerative amount.
The “regeneration rate limiter” is a gradient limit value of the regeneration amount set by the increase gradient α of the regeneration amount in the return start region when the ABS control intervention state is shifted to the ABS non-operation state and the regeneration cooperative brake control is returned. Say. The regenerative amount increase gradient α is determined by replacing the decrease-side gradient with the increase-side gradient in consideration of the hydraulic pressure response (decrease gradient) when the brake fluid pressure is released in the return start region. That is, the increase gradient α is determined so that there is no change in the total braking force including the hydraulic braking force and the regenerative braking force in the return start region.
“Executable regeneration amount” is executable that can be determined by taking into account the limitations due to the regeneration amount restriction conditions such as battery charge capacity, battery temperature, motor temperature, etc., to the maximum regeneration amount determined by the vehicle speed range, etc. Regenerative amount.

  In step S5, following the determination of the regenerative amount by select low in step S4, a regenerative braking request for obtaining the determined regenerative amount is output, and the process proceeds to the end.

  In step S6, following the determination that the ABS operation is in step S2, a stop of the regenerative braking request that sets the regenerative amount to zero is output, and the process proceeds to step S7.

  In step S7, following the stop of the regenerative braking request in step S6, the regenerative amount (= current value) immediately before the current ABS control intervention is detected, and the process proceeds to step S8.

  In step S8, following the regeneration amount detection during the ABS control intervention in step S7, it is determined whether or not the previous regeneration amount limiter (= previous limiter value) exceeds the current value. If YES (previous limiter value> current value), the process proceeds to step S9. If NO (previous limiter value ≦ current value), the process proceeds to step S10.

  In step S9, following the determination that the previous limiter value> current value in step S8, the next regeneration amount limiter is set to the current value, and the process proceeds to the end.

  In step S10, following the determination in step S8 that the previous limiter value ≦ current value, the next regeneration amount limiter is set to the previous limiter value, and the process proceeds to the end.

  In step S11, following the determination that there is no brake operation in step S1, the regeneration amount limiter set at that time is reset, and the process proceeds to the end.

Next, the operation will be described.
First, “a problem when ABS control intervenes during regenerative cooperative brake control in a comparative example” will be described. Subsequently, the actions in the brake control device of the hybrid vehicle of Example 1 are as follows: “Regenerative cooperative brake control system using VDC”, “Regenerative cooperative brake control action when ABS control is not intervening”, “At the time of ABS control intervention” The description will be divided into “regenerative cooperative brake control action” and “regenerative amount gradual increase action in the return start range for regenerative cooperative brake control”.

[Problems in regenerative cooperative brake control of comparative example]
For example, as described in Japanese Patent No. 3541646, when ABS control for preventing wheel lock is executed, the generation of regenerative braking force by the regenerative braking means is prohibited. Then, after the ABS control is finished during the brake operation, the one that prohibits the generation of the regenerative braking force during the brake operation is referred to as Comparative Example 1. Hereinafter, the problem in the regenerative cooperative brake control of Comparative Example 1 will be described with reference to FIG.

In the case of Comparative Example 1, once the ABS control is activated during one braking operation, the braking torque is maintained at zero regenerative torque until the braking operation ends after the control end time t2 has elapsed from the control start time t1. That is, return to regenerative cooperative brake control is prohibited.
For this reason, for example, at the time of low μ road braking where the ABS control operation frequency is high, the amount of regenerative energy by regenerative braking can be kept low. descend. In the case of an electric vehicle, the utility power cost is reduced.

  For example, as described in JP-A-6-171489, when ABS control for preventing wheel lock is executed, the generation of regenerative braking force by the regenerative braking means is prohibited. Then, when the ABS control is finished during the brake operation, the generation of the regenerative braking force is permitted, and the one that returns to the normal regenerative cooperative brake control is referred to as Comparative Example 2. Hereinafter, the problem in the regenerative cooperative brake control of the comparative example 2 will be described with reference to FIG.

  In the case of Comparative Example 2, the ABS control is operated from the control start time t1 to the end time t2 during one brake operation, and when the end time t2 is reached, as shown in the regenerative torque characteristic surrounded by the arrow A in FIG. Return to regenerative cooperative brake control to raise the regenerative torque to MAX. By returning to the regenerative cooperative brake control, the wheel speed decreases, and the ABS control is started at time t3 when the ABS intervention threshold is crossed. That is, by returning the regenerative cooperative brake control, as indicated by the wheel speed characteristics surrounded by the arrow B in FIG. 5, re-intervention of the ABS control is induced and the vehicle behavior is deteriorated. In addition, when the ABS control is deactivated, the operation returns to the regenerative cooperative brake control. However, the duration time after returning to the regenerative cooperative brake control is shortened, and the regenerative energy cannot be effectively secured.

[Regenerative cooperative brake control system using VDC]
First, in the regenerative cooperative brake control using VDC, if a scene occurs that cannot be compensated for by the basic hydraulic pressure and the regenerative component with respect to the target deceleration, the hydraulic pressure that cannot be compensated by the VDC brake hydraulic unit. This is the control that achieves the driver's required deceleration by pressurizing. A regenerative cooperative brake system using the VDC of the first embodiment adopted for performing this regenerative cooperative brake control will be described with reference to FIG.

  In the case of an existing conventional VDC, the driver's requested deceleration is obtained by the basic hydraulic pressure component by the negative pressure booster during brake operation. On the other hand, an offset is set from the driver requested deceleration so that the basic hydraulic pressure by the negative pressure booster does not reach the driver requested deceleration during braking, and the offset is insufficient for the driver requested deceleration. To do. At this time, by setting the regenerative gap by the maximum regenerative torque as an offset, when the maximum regenerative torque is generated, as shown in FIG. 6, the driver requested deceleration is reduced by the negative pressure booster (basic hydraulic pressure) and the regenerative brake. (Regeneration) is achieved to maximize the regenerative function.

  However, for example, depending on the vehicle speed condition, the battery charge capacity condition, etc., even if an attempt is made to achieve a deceleration that is insufficient for the basic hydraulic pressure with respect to the driver-requested deceleration, it may not be achieved. Therefore, when the maximum regenerative torque cannot be generated, the VDC pump up (pressurized part) for the deficiency in the sum of the negative pressure booster (basic hydraulic pressure) and regenerative brake (regenerative part) for the driver's requested deceleration The regenerative cooperative brake system using VDC is compensated by the above.

  Therefore, an inexpensive regenerative cooperative brake system using VDC can be configured by simply changing the characteristics of the negative pressure booster, the characteristics of the VDC brake hydraulic unit, and adding a stroke sensor to the existing conventional VDC. Can do. That is, the safety function of the conventional VDC is expanded (safety function + regenerative cooperation function).

[Regenerative cooperative brake control action when no ABS control is involved]
In the case of a hybrid vehicle, when braking, not all braking energy is consumed as thermal energy as in an engine vehicle, but recovering the battery as much of the braking energy as regenerative energy improves practical fuel efficiency. Is important above. Hereinafter, the regenerative cooperative brake control action at the time of ABS control non-intervention reflecting this will be described.

  If the ABS control is not activated and the regeneration permission condition is satisfied at the time of the brake operation, in the flowchart of FIG. 3, the flow proceeds from step S 1 → step S 2 → step S 3 → step S 4 → step S 5 → end. Repeated. That is, in step S4, the regeneration amount is determined based on the select row of the maximum regeneration amount and the executable regeneration amount. Since the ABS control is inactive, the regeneration amount limiter and the regeneration rate limiter are not set. In the next step S5, a regenerative braking request for obtaining the determined regenerative amount is output.

  Therefore, regenerative cooperative brake control by non-intervention of ABS control is performed as follows, for example. First, during a loss stroke in which master cylinder pressure is not generated by brake operation, the driver's required deceleration is achieved by the sum of the regenerative component that increases and the pressurized component (VDC_P / U). Then, when the loss stroke is completed and the master cylinder pressure is generated, the target deceleration is set to the basic hydraulic pressure component due to the increase in the master cylinder pressure, the regenerative component that increases, and the pressure component that decreases (VDC_P / U). Achieved by the sum of If the driver required deceleration is maintained at a constant value, the driver required deceleration is divided into the basic hydraulic pressure due to the constant master cylinder pressure, the maximum regeneration, and the constant pressure increase (VDC_P / U). Achieved by the sum of From the vehicle speed at which the regeneration limit is reached to the vehicle speed at which the regeneration is zero, the driver's requested deceleration is reduced to the basic hydraulic pressure due to a certain master cylinder pressure, the regenerative component that decreases, and the increasing acceleration. Achieved by summation of pressure component (VDC_P / U). And until the vehicle stops after the regeneration is zero, the driver's requested deceleration is the sum of the basic hydraulic pressure due to the constant master cylinder pressure and the constant pressure increase (VDC_P / U). Achieve.

  Therefore, in the regenerative cooperative brake control that is executed at the time of brake operation, the braking energy that is shared by regeneration among the braking energy that is required from when the brake operation starts to when the vehicle is stopped is used as the regenerative energy, and is collected in the in-vehicle battery. Can do.

[Regenerative cooperative brake control action during ABS control intervention]
As described in the problem of Comparative Example 1 above, if regeneration is prohibited during ABS control intervention, regenerative energy cannot be secured. On the other hand, as described in the problem of Comparative Example 2 above, if normal regeneration is resumed at the time of ABS control intervention, ABS control re-intervention is inevitable. Thus, it is necessary to devise ways to improve the trade-off relationship that is difficult to achieve. Hereinafter, the regenerative cooperative brake control action at the time of ABS control intervention reflecting this will be described.

  When the operation of the ABS control is started by the intervention of the ABS control during the brake operation, the process proceeds from step S1 to step S2 to step S6 in the flowchart of FIG. 3, and the regenerative braking request is stopped in step S6. As described above, during the regenerative cooperative brake control, when the ABS control intervenes at time t1 in FIG. 8, during the ABS control intervention from time t1 to time t2 (ABS operation flag ON), the regenerative torque zero is maintained and the regenerative torque is maintained. The braking request is stopped.

  That is, the ABS control is a control that suppresses the brake lock by reducing the brake fluid pressure to reduce the hydraulic braking force. On the other hand, the addition of a regenerative braking force that increases the braking force during the ABS control does not adversely affect the suppression of braking lock or delay the suppression of braking lock. Control interference of regenerative cooperative brake control is prevented. As a result, when the ABS control operation is started, the regenerative braking request is stopped, so that the braking lock is quickly suppressed by the ABS control as shown in the wheel speed characteristics from time t1 to time t2 in FIG. It is done.

  When the previous limiter value> the current value, the process proceeds from step S6 to step S7 → step S8 → step S9. In step S9, the regeneration amount limiter is set to the current value which is the regeneration amount immediately before the ABS intervention. On the other hand, when the previous limiter value ≦ the current value, the process proceeds from step S6 to step S7 → step S8 → step S10. In step S10, the regeneration amount limiter is set to the previous limiter value. That is, the value is set to a value that does not exceed the previous limiter value as the regeneration amount limiter when returning to the regeneration cooperative brake control next time.

  Thus, when returning to the regenerative cooperative brake control next time, it is possible to return to the regenerative cooperative brake control with the regenerative torque MAX (= maximum regenerative torque). On the other hand, as indicated by an arrow C in FIGS. 7 and 8, the regeneration amount is limited from the value of the regeneration torque MAX to the value of the regeneration torque limiter (= the regeneration amount limiter). The value of the regenerative torque limiter is the regenerative amount at time t1 in FIG. 8 immediately before the current ABS control intervention.

  That is, as in Comparative Example 2, when an unrestricted regenerative braking request is made when returning to regenerative cooperative brake control, the braking force at the time of return to the regenerative wheel becomes excessive, and re-intervention of ABS control is induced, The frequency of re-intervention increases. On the other hand, the limited regenerative braking request, as shown in FIG. 8, suppresses the decrease in wheel speed that crosses the ABS intervention threshold after the return time t2, and eliminates re-intervention of ABS control. In addition, the frequency of ABS control re-intervention can be reduced. As a result, when shifting from the ABS control intervention state to the ABS control non-operation state, the duration of the regenerative cooperative brake control by the limited regenerative braking request is secured.

  When the ABS control is shifted from the operation to the non-operation and the regeneration permission condition is satisfied, the flow of step S1, step S2, step S3, step S4, step S5, and the end is repeated in the flowchart of FIG. Return to regenerative cooperative brake control. That is, in step S4, the regeneration amount is determined by selecting the maximum regeneration amount, regeneration amount limiter, regeneration rate limiter, and executable regeneration amount. As described above, when the time t2 in FIG. 8 at which the ABS control shifts to the non-operating state is reached, the regenerative cooperative brake control with the regeneration amount limiter as the upper limit value is returned from the time t2.

  That is, the regenerative prohibition frequency is reduced as compared with the case where the regenerative braking is prohibited even when the ABS control shifts to the non-operating state as in the first comparative example. In addition, as described above, the regenerative cooperative brake control that has been restored is continued by suppressing the re-intervention frequency of the ABS control by the limited regenerative braking request, as shown in the D region (hatching region) in FIG. The amount of regenerative energy by regenerative braking is effectively secured. As a result, in the hybrid vehicle, the travel distance in the EV mode (electric vehicle travel mode) is extended, and the practical fuel consumption is improved. In particular, at the time of low μ road braking where the frequency of ABS control intervention is high, the cost for improving the practical fuel consumption increases.

As described above, in the first embodiment, when the ABS control intervenes during the regenerative cooperative brake control, the regenerative braking request is stopped during the ABS control intervention (step S6 in FIG. 3). Then, when the ABS control shifts to the non-operating state, the regenerative cooperative brake control is returned to the regenerative cooperative brake control with the limited regenerative braking request using the regenerative amount limited to the value not exceeding the regenerative amount at the previous ABS control intervention as the current regenerative amount limiter. The structure to adopt was adopted (step S1-step S5 of FIG. 3).
Therefore, when ABS control intervenes during regenerative cooperative brake control, prevention of control interference, suppression of the frequency of control re-intervention, and effective securing of the amount of regenerative energy are achieved together.

As described above, in the first embodiment, when the regenerative braking request is stopped by the intervention of the ABS control, the regeneration amount immediately before the ABS control intervention is detected. And the structure which sets the regeneration amount limiter when ABS control transfers to a non-operation state next time based on this regeneration amount detection value and the last regeneration amount limiter was employ | adopted (step S7-step S10 of FIG. 3). .
With this configuration, at the time of the ABS control intervention, the regeneration amount limiter when the ABS control shifts to the non-operating state next time is set based on the regeneration amount immediately before the ABS control intervention that induced the intervention of the ABS control this time. .
Therefore, in preparation for the return to the next regeneration cooperative brake control, a regeneration amount limiter that suppresses the induction of re-intervention of the ABS control is set in advance while the ABS control is intervening.

[Regenerative amount gradual increase in the return start range to regenerative cooperative brake control]
When returning from the ABS control intervention state to the regenerative cooperative brake control, the braking force rapidly increases in the return start region for the regenerative cooperative brake control due to the difference between the hydraulic pressure response speed and the regenerative response speed. For this reason, it is necessary to eliminate the influence due to the difference in response speed in the return start range to the regenerative cooperative brake control. Hereinafter, the regeneration amount gradual increase action in the return start range to the regeneration cooperative brake control reflecting this will be described.

  When the ABS control is shifted from the operation to the non-operation and the regeneration permission condition is satisfied, the flow of step S1, step S2, step S3, step S4, step S5, and the end is repeated in the flowchart of FIG. Return to brake control. In this return start region, in step S4, the regeneration amount is determined by the regeneration rate limiter that is the regeneration amount that increases with the increasing gradient α. In this way, in the return start range for the regenerative cooperative brake control, the regenerative torque rises from zero with an increasing gradient α as shown in the regenerative torque characteristic from time t2 to time t3 in FIG.

  That is, when the time t2 in FIG. 8 is returned to return to the regenerative cooperative brake control, the operation of releasing the brake fluid pressure and the operation of adding the regenerative amount are started simultaneously. At this time, if the regeneration amount is immediately returned to the regeneration amount limiter while releasing the brake fluid pressure, it remains in the return start range for the regenerative cooperative brake control due to the difference between the slow hydraulic response speed and the fast regeneration response speed. The regenerative braking force is added to the hydraulic braking force, and the total braking force increases rapidly.

  On the other hand, the regeneration amount is increased by the increasing gradient α in the return start region to the regeneration cooperative brake control from the time t2 to the time t3 in FIG. Therefore, as shown in Fig. 7, when switching the VDC pump up (VDC_P / U) to regenerative braking, the reduction in deceleration due to the response delay caused by releasing the brake fluid pressure of the VDC pump up (VDC_P / U) The minute is compensated with a regenerative brake intentionally delayed in response. For this reason, the change of the total braking force is suppressed in the return start range to the regenerative cooperative brake control. As a result, the longitudinal acceleration fluctuation (G fluctuation) of the vehicle due to the switching of the braking force generation source in one braking time (hydraulic pressure → regeneration) is suppressed to the minimum.

As described above, in the first embodiment, when returning to the regenerative cooperative brake control due to the limited braking request by shifting the ABS control to the non-operating state, the increase gradient α of the regenerative amount in the return start region is set as the brake hydraulic pressure. A configuration that takes into account the hydraulic pressure response when pulling out was adopted.
With this configuration, the influence due to the difference between the hydraulic pressure response speed and the regeneration response speed is eliminated in the return start range to the regeneration cooperative brake control.
Therefore, in the return start range for the regenerative cooperative brake control, the change in the total braking force is suppressed, and the G variation of the vehicle due to the replacement of the braking force generation source is minimized.

Next, the effect will be described.
In the hybrid vehicle brake control device of the first embodiment, the following effects can be obtained.

(1) hydraulic braking means (brake hydraulic pressure generator 1) for applying brake hydraulic pressure to the wheel cylinders 4FL, 4FR, 4RL, 4RR provided on the front and rear wheels during braking operation;
Regenerative amount control means (motor controller 8) for controlling the regenerative amount in response to a command to the electric motor 5 for traveling connected to the drive wheel during braking operation;
Regenerative cooperative brake control means (integrated controller) that performs control to achieve a braking target value (driver-requested deceleration) by the sum of the hydraulic braking force by the brake hydraulic pressure and the regenerative braking force by the regenerative amount during brake operation 9)
When the wheel is likely to be locked during braking, the brake fluid pressure to the wheel cylinders 4FL, 4FR, 4RL, 4RR is controlled by the command to the brake fluid pressure actuator (VDC brake fluid pressure unit 2) so as to suppress the brake lock. Anti-lock brake control means (brake controller 7) for increasing and decreasing the control,
When the ABS control intervenes during the regenerative cooperative brake control, the value that does not exceed the regenerative amount at the previous ABS control intervention when the regenerative braking request is stopped during the ABS control intervention and the ABS control shifts to the non-operating state. Regenerative cooperative brake control means (FIG. 3) at the time of ABS intervention for returning to the regenerative cooperative brake control by the limited regenerative braking request with the regenerative amount limited to the regenerative amount upper limit value (regenerative amount limiter);
Is provided.
For this reason, when ABS control intervenes during regenerative cooperative brake control, the prevention of control interference between ABS control and regenerative cooperative brake control, suppression of the frequency of ABS control re-intervention, and the effectiveness of securing the amount of regenerative energy are combined. Can be achieved.

(2) When the ABS intervention regenerative cooperative brake control means (FIG. 3) returns to the regenerative cooperative brake control by the limited braking request by shifting to the non-operating state of the ABS control, the regeneration amount increases in the return start range. The gradient α is determined in consideration of the hydraulic pressure response when the brake hydraulic pressure is released.
For this reason, in addition to the effect of (1) above, the change of the total braking force is suppressed in the return start range to the regenerative cooperative brake control, and the G variation of the vehicle due to the replacement of the braking force generation source is minimized. Can do.

(3) The regenerative cooperative brake control means at the time of ABS intervention detects the regenerative amount immediately before this ABS control intervention when the regenerative braking request is stopped by the intervention of ABS control, Based on the regeneration amount upper limit value (regeneration amount limiter), the regeneration amount upper limit value (regeneration amount limiter) when the ABS control shifts to the non-operation state next time is set.
Therefore, in addition to the effect of (1) or (2) above, the upper limit of the regenerative amount that suppresses the induction of re-intervention of ABS control while ABS control is intervening in preparation for the return to the next regenerative coordinated brake control A value (regeneration amount limiter) can be set in advance.

  As mentioned above, although the brake control apparatus of the electric vehicle of this invention has been demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, It concerns on each claim of a claim Design changes and additions are allowed without departing from the scope of the invention.

  In the first embodiment, as the regenerative cooperative brake control means at the time of ABS intervention, the regenerative amount limiter in the regenerative cooperative brake control at the next return is set to the current value that is the regenerative amount immediately before the current ABS control intervention, or the previous regenerative brake control unit. An example in which the previous limiter value, which is a quantity limiter, is not exceeded is shown. However, the timing for determining the regeneration amount upper limit value may be an example of determining the current regeneration amount upper limit value so as not to exceed the previous regeneration amount when returning to regeneration cooperative brake control. In addition, the current regeneration amount upper limit value in the regenerative cooperative brake control that has been restored is a value that does not exceed the regeneration amount at the previous ABS control intervention, for example, a value slightly smaller than the regeneration amount at the previous ABS control intervention. Alternatively, the value may be smaller by a predetermined value. Also in these cases, when the ABS control intervenes, the regenerative amount can be increased as compared with the case where the regenerative cooperative brake control is prohibited.

  In the first embodiment, an example in which the driver requested deceleration is used as the braking target value is shown. However, as the braking target value, a target deceleration, a target braking force, a driver request braking force, or the like may be used.

  In the first embodiment, the brake fluid pressure generator 1 having the negative pressure booster 12 with a unique boost characteristic is used as the fluid pressure braking means for applying the brake fluid pressure to the wheel cylinders 4FL, 4FR, 4RL, 4RR. An example is shown. However, as the hydraulic braking means, for example, a brake hydraulic pressure generating device having an electric booster that has a high degree of freedom in controlling the boost characteristic and can accurately handle regenerative cooperative brake control may be used.

  In Example 1, the example using the VDC brake hydraulic pressure unit 2 shown in FIG. 2 as a brake hydraulic pressure actuator was shown. However, as a brake hydraulic pressure actuator, an ABS brake hydraulic pressure actuator or the like may be used as long as it is a brake hydraulic pressure actuator capable of ABS control.

  In the first embodiment, the brake control device of the present invention is applied to a front-wheel drive hybrid vehicle. However, if the vehicle is an electric vehicle such as a rear-wheel drive hybrid vehicle, an electric vehicle, a fuel cell vehicle, or the like and performs regenerative cooperative brake control and ABS control using a hydraulic braking force and a regenerative braking force, the brake control according to the present invention. The device can be applied.

1 Brake hydraulic pressure generator (hydraulic braking means)
2 VDC brake fluid pressure unit (brake fluid pressure actuator)
3 Stroke sensor 4FL Left front wheel wheel cylinder 4FR Right front wheel wheel cylinder 4RL Left rear wheel wheel cylinder 4RR Right rear wheel wheel cylinder 5 Driving electric motor 61 Primary hydraulic pipe 62 Secondary hydraulic pipe 63 Left front wheel hydraulic pipe 64 Right front wheel hydraulic pipe 65 Left Rear wheel hydraulic pipe 66 Right rear wheel hydraulic pipe 7 Brake controller (anti-lock brake control means)
8 Motor controller (regenerative braking force control means)
9 Integrated controller (regenerative cooperative brake control means)

Claims (3)

A hydraulic braking means for applying a brake hydraulic pressure to a wheel cylinder provided on each of the front and rear wheels during a brake operation;
Regenerative amount control means for controlling the regenerative amount in response to a command to the electric motor for traveling connected to the drive wheel during brake operation;
Regenerative cooperative brake control means for performing control to achieve a braking target value as a sum of a hydraulic braking force by the brake hydraulic pressure and a regenerative braking force by the regenerative amount at the time of braking operation;
An anti-lock brake control means for increasing / decreasing the brake fluid pressure to the wheel cylinder so as to suppress the brake lock by a command to the brake fluid pressure actuator when the wheel is likely to be brake-locked during a brake operation;
When the anti-lock brake control intervenes during the regenerative cooperative brake control, the regenerative braking request is stopped during the anti-lock brake control intervention, and when the anti-lock brake control shifts to the inactive state, the previous anti-lock brake control intervention is performed. Regenerative cooperative brake control means at the time of ABS intervention for returning to the regenerative cooperative brake control by the limited regenerative braking request with the regenerative amount limited to a value not exceeding the regenerative amount at the time as the current regenerative amount upper limit value;
A brake control device for an electric vehicle, comprising: In the brake control device for an electric vehicle according to claim 1,
The regenerative cooperative brake control means during the ABS intervention, when returning to the regenerative cooperative brake control due to the restricted braking request by shifting to the non-operating state of the antilock brake control, A brake control device for an electric vehicle, wherein the brake control device is determined in consideration of a hydraulic pressure responsiveness when the pressure is released. In the brake control device for an electric vehicle according to claim 1 or 2,
The regenerative cooperative brake control means at the time of ABS intervention detects the regenerative amount immediately before the current antilock brake control intervention when the regenerative braking request is stopped by the intervention of the antilock brake control, A brake control device for an electric vehicle characterized in that, based on the previous regeneration amount upper limit value, a regeneration amount upper limit value when the anti-lock brake control is shifted to a non-operation state next time is set.