JP2001047993A - Brake controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize a delivered brake-fluid pressure of hydraulic pumps by controlling properly a modulator to smoothly and surely conduct various kinds of braking controls. SOLUTION: In this controller, a brake fluid of a master cylinder MC is delivered to a wheel cylinder Wfr and the like by hydraulic pumps HP1, HP2 via a modulator (opening and closing valve PC1 and the like). When the modulator is regulated to increase a brake fluid pressure of the wheel cylinder Wfr, the pumps HP1, HP2 are driven continously, and the second opening and closing valves S11, S12 are brought into opened conditions. Time of the remainder at the time when a required pressure-increasing time for the wheel cylinder Wfr is divided by a time corresponding to a delivery time during one cycle of the hydraulic pumps HP1, HP2 to get an integer quotient is computed, it is repeated by the number of times corresponding to the quoatient that the modulator is brought into an opened condition during a time corresponding to the delivery time and that it is brought thereafter into a closed condition, and it is brought into an opened condition during time corresponding to the remainder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake control device for performing various types of braking control such as braking steering control and brake assist control. More particularly, the present invention relates to a brake pump for hydraulically pumping master cylinder brake fluid through a modulator. The present invention relates to a vehicle brake control device provided with a brake fluid pressure control device that discharges to a cylinder.

[0002]

2. Description of the Related Art For example, Japanese Patent Laying-Open No. 2-70561 proposes a motion control device for maintaining the stability of a vehicle by a braking control means for compensating for the influence of the lateral force of the vehicle.
In this device, the braking control means controls the braking force on the vehicle according to the comparison result of the actual yaw rate and the target yaw rate, and for example, ensures stability even when the vehicle moves during cornering. Can be maintained. Accordingly, a braking force is applied to each wheel regardless of whether or not the brake pedal is operated, and so-called braking steering control performs oversteer suppression control and understeer suppression control.

A traction (TRC) control device for controlling a braking force on a driving wheel when an acceleration slip occurs when a brake pedal is not operated is disclosed in Japanese Patent Application Laid-Open No. Hei 5-116609. "ABS with two brake circuits, individual control of the wheels by means of ABS valves, a self-contained pump for each brake circuit for returning the brake fluid discharged during control to the brake circuit,
A Brake pressure control system for an all-wheel drive vehicle including a brake ASR that uses a return pump to supply brake pressure in the case of ASR, and aims to "make a brake apply even during ASR operation." An apparatus is also disclosed (the terms and expressions in parentheses refer directly to the publication).

On the other hand, while the vehicle is running, for example, during emergency braking, the brake pedal is depressed at a rapid speed, but the pedaling force is insufficient or it is difficult to maintain the pedaling force, so that an appropriate braking force may not be obtained. . Further, even in a vehicle provided with an anti-skid control device (ABS), the anti-skid control does not start due to insufficient pedaling force of the brake pedal, and the function of turning angle cannot be sufficiently exhibited. . In view of such a point, it has recently been proposed to add a brake assist control function, and it has already been provided in some commercial vehicles. This brake assist control is to assist the driver's brake pedal operation by automatically increasing the braking force when the brake pedal is depressed at a rapid speed or when the brake pedal is deeply depressed, In general, control of the doubler function of the vacuum booster is performed.

[0005] Japanese Patent Application Laid-Open No. 11-129878 discloses that when the system shifts to the anti-skid control during the brake assist control, or when the system shifts to the anti-skid control during the brake steering control, etc. If the pulse pressure increase mode that repeats pressure increase and hold is selected for the wheel cylinders of the two wheels, the time during which the suction valve is closed is shortened, so the pump pumps out the brake fluid in the reservoir. In view of the fact that the time that can be performed is shortened, a braking control device has been proposed to solve this problem.

That is, a vehicle equipped with a brake fluid pressure control device for discharging brake fluid of a master cylinder to a wheel cylinder via a modulator by a hydraulic pump and storing brake fluid of the wheel cylinder in a reservoir via a modulator. In the brake control device, the brake fluid stored in the brake control reservoir is appropriately discharged by a hydraulic pump so that the hydraulic pressure control in the brake steering control, the brake assist control, the anti-skid control, and the like can be appropriately and reliably performed. There has been proposed a braking control device which has a problem to be solved.

[0007]

The hydraulic pump used in the above-described braking control device is generally driven by a motor, and is configured so that suction and discharge are periodically repeated. Therefore, the discharge amount when the hydraulic pump makes one rotation can be calculated according to the time of one cycle of the electric motor, and the amount of brake fluid actually discharged corresponds to the time of approximately one half cycle. are doing. Conventionally, during the pressure increase control in the rapid pressure increase mode and the pulse pressure increase mode, the modulator for controlling the wheel cylinder hydraulic pressure is held in the open state, but the brake hydraulic pressure control for other wheels in the same hydraulic system is performed. For example, in order to avoid a so-called sneak path, time is naturally limited. For this reason, depending on the control situation, there is a possibility that the target hydraulic pressure cannot be reached. In order to avoid this, it is only necessary to control so that the timing of opening the modulator during the wheel cylinder hydraulic pressure control is synchronized with the discharge timing of the hydraulic pump.
Although it is also proposed in Japanese Patent No. 9878, it is not always easy.

In a general brake hydraulic pressure control device, the hydraulic pressure discharged from a hydraulic pump is supplied to a modulator via a damper or the like. When the opening / closing timing is not necessarily synchronized with the timing of the suction / discharge cycle of the hydraulic pump, the control of the modulator is synchronized by repeatedly controlling the open state and the holding state. The same effect as described above can be obtained, and there is no possibility that the target hydraulic pressure is not reached due to the above-described hydraulic pressure of the hydraulic pump, and the suction of the hydraulic pump as in the case where the modulator is kept open. It is also possible to prevent the backflow of brake fluid from the modulator side to the hydraulic pump side during a cycle.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a brake control apparatus for a vehicle having a brake fluid pressure control device for discharging a brake fluid of a master cylinder to a wheel cylinder via a modulator by a hydraulic pump. Accordingly, it is an object of the present invention to effectively utilize the discharge brake hydraulic pressure of a hydraulic pump so that various braking controls can be smoothly and reliably performed.

[0010]

According to the present invention, there is provided a brake for applying a braking force to at least each wheel of a vehicle according to an operation of a brake pedal. A brake pressure control device for a vehicle, comprising: a brake pressure control device, and a brake control unit configured to control the brake fluid pressure control device to control a braking force on each wheel of the vehicle. A wheel cylinder attached to each wheel of the vehicle to apply a braking force, a master cylinder that boosts brake fluid in response to operation of the brake pedal and outputs a master cylinder fluid pressure, and each of the master cylinder and the wheel cylinder. Are connected via a plurality of hydraulic systems, and are mounted on the hydraulic system to adjust the brake hydraulic pressure of the wheel cylinders in accordance with the control by the braking control means. A hydraulic pump for discharging brake fluid periodically pressurized to the wheel cylinder via the modulator; a reservoir for storing brake fluid discharged from the wheel cylinder via the modulator; and a master cylinder. A normally open first on-off valve for opening and closing a hydraulic path for communicating and connecting the modulator and a normally closed second open / close valve for opening and closing a hydraulic path for communicating and connecting the master cylinder and the suction side of the hydraulic pump. And the brake control means, when adjusting the modulator so as to increase the brake fluid pressure of the wheel cylinder, continuously drives the hydraulic pump and performs the second open / close operation. With the valve in the open position, the required pressure increase time for the wheel cylinder is divided by the time corresponding to the discharge time in one cycle of the hydraulic pump. The remainder time when the quotient of the number is obtained is calculated, and the modulator is opened and closed for the time corresponding to the discharge time by the number of times of the quotient, and the remainder time is repeated. The modulator is configured to be in an open state.

The required pressure increasing time for the wheel cylinder is appropriately set by the braking control means according to the control state. When the required pressure increase time is less than the time corresponding to the discharge time in one cycle of the hydraulic pump, only the surplus value is set, and the required pressure increase time at that time is actually used by the hydraulic pump as it is. It is time to increase the pressure.

The brake control means may control the time corresponding to one cycle of the hydraulic pump immediately after the adjustment of the modulator is started so that the brake hydraulic pressure of the wheel cylinder is increased. During this time, the modulator may be configured to be kept closed.

Further, the braking control means may be configured to set the second on-off valve to a closed position after the lapse of the total pressure increasing time.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, an overall configuration of an embodiment of the present invention will be described with reference to FIG. Engine EG
Is an internal combustion engine provided with a throttle control device TH and a fuel injection device FI. In the throttle control device TH, a main throttle opening of a main throttle valve MT is controlled according to an operation of an accelerator pedal AP. Further, the throttle control device T is controlled according to the output of the electronic control device ECU.
The H sub-throttle valve ST is driven to control the sub-throttle opening, and the fuel injection device FI is driven to control the fuel injection amount. The engine EG of the present embodiment is connected to wheels FL and FR in front of the vehicle via a shift control device GS, and has a so-called front wheel drive system. However, the drive system in the present invention is not limited to this. Absent.

As for the braking system, the wheels FL, FR, R
Wheel cylinders Wfl, Wfr, Wr for L and RR, respectively
1, Wrr are mounted, and a brake fluid pressure control device BC is connected to these wheel cylinders Wfl and the like. The wheel FL indicates the front left wheel when viewed from the driver's seat, the wheel FR indicates the front right wheel, the wheel RL indicates the rear left wheel, and the wheel RR indicates the rear right wheel. In the present embodiment, a so-called X pipe is configured. However, it may be a front and rear pipe.

The wheels FL, FR, RL, RR are provided with wheel speed sensors WS1 to WS4, which are connected to the electronic control unit ECU. The rotation speed of each wheel, that is, the pulse number proportional to the wheel speed, is provided. Is input to the electronic control unit ECU. Further, the brake switch BS which is turned on when the brake pedal BP is depressed, the steering angle δf of the wheels FL and FR in front of the vehicle.
, A lateral acceleration sensor YG for detecting the lateral acceleration of the vehicle, and a yaw rate for detecting a changing speed of the vehicle rotation angle (yaw angle) around a vertical axis passing through the center of gravity of the vehicle, that is, a yaw angular speed (yaw rate). The sensors YS and the like are connected to the electronic control unit ECU.

The electronic control unit ECU of the present embodiment has a configuration shown in FIG.
As shown in FIG. 1, a microcomputer CMP comprising a processing unit CPU, a memory ROM, a RAM, an input port IPT, an output port OPT, and the like, which are interconnected via a bus, is provided. The wheel speed sensor WS
1 to WS4, brake switch BS, front wheel steering angle sensor SSf, yaw rate sensor YS, lateral acceleration sensor YG, etc.
It is configured to be input from the PT to the processing unit CPU. Further, control signals are output from the output port OPT to the throttle control device TH and the brake fluid pressure control device BC via the drive circuit ACT.

In the microcomputer CMP,
The memory ROM stores programs for various processes including the flowcharts shown in FIGS. 3 to 7, the processing unit CPU executes the programs while an ignition switch (not shown) is closed, and the memory RAM executes the programs. Temporarily stores the variable data required for the execution of For each control such as throttle control,
Alternatively, a plurality of microcomputers may be configured by appropriately combining related controls, and the microcomputers may be electrically connected to each other.

As shown in FIG. 1, in the braking system including the above-described brake fluid pressure control device BC, the master cylinder MC is boosted through the vacuum booster VB in response to the operation of the brake pedal BP, and the low-pressure reservoir LRS The brake fluid inside is pressurized and the wheels FR, RL and the wheels FL, RR
The master cylinder hydraulic pressure is output to the two brake hydraulic systems on the side. The master cylinder MC is a tandem type master cylinder having two pressure chambers.
One of the pressure chambers is connected to a brake hydraulic system on the wheels FR and RL, and the other pressure chamber is connected to a brake hydraulic system on the wheels FL and RR. The output side of the master cylinder MC is provided with a pressure sensor PS for detecting the output hydraulic pressure (master cylinder hydraulic pressure).

The vacuum booster VB according to the present embodiment comprises:
The configuration is the same as that of the conventional vacuum booster, and a constant pressure chamber B2 and a variable pressure chamber B3 are formed via a movable wall B1, and the movable wall B1 is connected to a brake pedal BP. The movable wall B1 includes a vacuum valve (not shown) for interrupting communication between the constant pressure chamber B2 and the variable pressure chamber B3, and an air valve (not shown) for interrupting communication between the variable pressure chamber B3 and the atmosphere. A valve mechanism B4 is provided. And
The constant pressure chamber B2 is configured to always communicate with an intake manifold (not shown) of the engine EG and to introduce a negative pressure. On the other hand, the variable pressure chamber B3 is operated by the valve mechanism B4.
A state in which it is isolated from the constant pressure chamber B2 and communicates with the atmosphere;
It is configured to select a state in which a negative pressure is introduced in communication with the second pressure. Thus, the vacuum valve and the air valve of the valve mechanism B4 open and close in response to the operation of the brake pedal BP, and a differential pressure corresponding to the operation force of the brake pedal BP is generated between the constant pressure chamber B2 and the variable pressure chamber B3. As a result, the output amplified according to the operation force of the brake pedal BP is transmitted to the master cylinder MC.

In the vacuum booster VB of this embodiment, an auxiliary movable wall B5 is further disposed in the constant pressure chamber B2, and an auxiliary variable pressure chamber B6 is formed between the auxiliary movable wall B1 and the movable wall B1. The auxiliary movable wall B5 can move in the direction of the master cylinder MC along with the movement of the brake pedal BP, but is configured to move in the direction of the master cylinder MC independently of the brake pedal BP and drive it. That is, depending on the operation of the booster switching valve SB, the auxiliary transformer chamber B6 is selected between a state in which it communicates with the atmosphere and a state in which it communicates with an intake manifold (not shown) of the engine EG to introduce a negative pressure. It is configured as follows. Booster switching valve SB is 3
As shown in FIG. 1, the auxiliary variable pressure chamber B6 is connected to the intake manifold of the engine EG together with the constant pressure chamber B2 at the first position in the off state (normal state). At the set second position, the auxiliary transformation chamber B6 is switched to communicate with the atmosphere (indicated by AR in FIG. 1).

If a negative pressure is introduced into the auxiliary variable pressure chamber B6 via the booster switching valve SB, the auxiliary movable wall B5 is maintained at a fixed distance with respect to the movable wall B1, and the auxiliary movable wall B5 is moved with the movement of the brake pedal BP. Although it moves in the direction of the master cylinder MC, when the auxiliary variable pressure chamber B6 communicates with the atmosphere, a differential pressure is generated between the auxiliary variable pressure chamber B6 and the negative pressure constant pressure chamber B2.
The master cylinder MC is driven in response to the movement of the auxiliary movable wall B5 irrespective of the operation of P (even if the provisional command and the brake pedal BP are not operated).

In the brake hydraulic system for the wheels FR and RL of the present embodiment, one pressure chamber is connected to the wheel cylinders Wfr and Wrl via the main hydraulic path MF and the branch hydraulic paths MFr and MFl, respectively. Have been. Main hydraulic path MF
A normally open first on-off valve SC1 (which functions as a so-called cut-off valve, hereinafter simply referred to as on-off valve SC1) is interposed. One of the pressure chambers is an auxiliary hydraulic pressure path MF.
It is connected between check valves CV5 and CV6 described later via c. A normally closed second on-off valve S is provided in the auxiliary hydraulic pressure path MFc.
I1 (hereinafter simply referred to as on-off valve SI1) is interposed. Each of these on-off valves is constituted by a 2-port 2-position electromagnetic on-off valve. The branch hydraulic pressure paths MFr and MFl are normally open two-port two-position solenoid on-off valves PC1 and PC1, respectively.
2 (hereinafter simply referred to as on-off valves PC1 and PC2). In parallel with these, check valves CV1 and CV1, respectively
V2 is interposed.

The check valves CV1 and CV2 allow the flow of the brake fluid in the direction of the master cylinder MC and restrict the flow of the brake fluid in the direction of the wheel cylinders Wfr and Wrl. The brake fluid in the wheel cylinders Wfr and Wrl is supplied to the master cylinder MC via the on-off valve SC1 at the first position (the state shown).
Thus, it is configured to be returned to the low pressure reservoir LRS. Thus, when the brake pedal BP is released, the hydraulic pressure in the wheel cylinders Wfr and Wrl can quickly follow the decrease in hydraulic pressure on the master cylinder MC side. Also,
Normally closed two-port two-position solenoid on-off valves PC5 and PC6 (hereinafter simply referred to as on-off valves PC5 and PC6) are respectively connected to discharge-side branch hydraulic pressure paths RFr and RFl that are connected to and connected to the wheel cylinders Wfr and Wrl. And the discharge hydraulic pressure line RF where the branch hydraulic pressure lines RFr and RFl merge is connected to the reservoir R
It is connected to S1.

In the brake hydraulic system on the wheels FR and RL, a modulator is constituted by the on-off valves PC1, PC2, PC5 and PC6. In addition, on-off valve P
A hydraulic pump HP1 is interposed in a hydraulic passage MFp that is connected to the branch hydraulic passages MFr and MFl on the upstream side of C1 and PC2, and a reservoir RS1 is provided on the suction side thereof through check valves CV5 and CV6. It is connected. Also, the hydraulic pump HP1
Is connected to on-off valves PC1 and PC2 via a check valve CV7 and a damper DP1, respectively. The hydraulic pump HP1 is provided with one electric motor M together with the hydraulic pump HP2.
, The brake fluid is introduced from the suction side, boosted to a predetermined pressure, and output from the discharge side. The reservoir RS1 is provided independently of the low-pressure reservoir LRS of the master cylinder MC, and can also be referred to as an accumulator. The reservoir RS1 includes a piston and a spring, and can store brake fluid having a capacity necessary for various controls described later. Is configured.

The master cylinder MC is connected to a check valve CV5 and a check valve C on the suction side of the hydraulic pump HP1 via a hydraulic passage MFc.
It is connected to V6. The check valve CV5 prevents the flow of the brake fluid to the reservoir RS1, and allows the flow in the reverse direction. Check valves CV6, CV7
Regulates the flow of brake fluid discharged through the hydraulic pump HP1 in a certain direction.
1 are integrally formed. Thus, the on-off valve SI1
1 is switched so that the communication between the master cylinder MC and the suction side of the hydraulic pump HP1 is interrupted at the normal closed position shown in FIG. 1 and the master cylinder MC and the suction side of the hydraulic pump HP1 are communicated at the open position.

Further, the flow of the brake fluid from the master cylinder MC toward the on-off valves PC1 and PC2 is restricted in parallel with the on-off valve SC1, and the brake fluid pressure on the on-off valves PC1 and PC2 side becomes the brake fluid on the master cylinder MC side. The relief valve RV1 allows the flow of the brake fluid in the direction of the master cylinder MC when the pressure becomes larger than the predetermined differential pressure with respect to the pressure. A check valve AV1 for inhibiting flow is interposed. When the pressurized brake fluid discharged from the hydraulic pump HP1 becomes larger than the output hydraulic pressure of the master cylinder MC by a predetermined differential pressure or more, the relief valve RV1 supplies the brake fluid to the low-pressure reservoir LRS via the master cylinder MC. The pressure of the discharge brake fluid of the hydraulic pump HP1 is adjusted to a predetermined pressure. Also, the hydraulic pump H
A damper DP1 is disposed on the discharge side of P1, and a proportioning valve PV1 is interposed in a hydraulic path leading to a wheel cylinder Wrl on the rear wheel side.

Similarly, in the brake hydraulic system on the side of the wheels FL and RR, a normally open 2-port 2-position solenoid valve SC2 (first valve) including a reservoir RS2, a damper DP2 and a proportioning valve PV2. , Normally closed 2-port 2-position solenoid valve SI2 (second valve), P
C7, PC8, normally open 2-port 2-position solenoid on-off valve PC
3, PC4, check valve CV3, CV4, CV8 to CV1
0, a relief valve RV2 and a check valve AV2 are provided. The hydraulic pump HP2 is driven by the electric motor M together with the hydraulic pump HP1, and after the electric motor M is started, both the hydraulic pumps HP1 and HP2 are continuously driven. On-off valve SC1, SC2, SI1, SI2 and on-off valve PC
The PCs 1 to 8 are driven and controlled by the above-mentioned electronic control unit ECU, and various controls including a brake steering control are performed.

First, during normal braking operation,
Each solenoid valve is in the normal position shown in FIG. 1, and the electric motor M is stopped. When the brake pedal BP is depressed in this state, the master cylinder MC is boosted by the vacuum booster VB, and the master cylinder hydraulic pressure is supplied from the two pressure chambers of the master cylinder MC to the wheels FR and RL, respectively.
Valves SC1 and SC2 and on-off valves PC1 through PC
8, the wheel cylinders Wfr, Wrl, Wf
1, Wrr. Wheel FR, RL side and wheel F
Since the brake hydraulic systems on the L and RR sides have the same configuration, the brake hydraulic system on the wheels FR and RL will be representatively described below.

For example, when the control is shifted to the anti-skid control during the braking operation and, for example, it is determined that the wheel FR side is in a locking tendency, the opening / closing valve PC1 is set to the closing position while the opening / closing valve SC1 is kept in the open position. , The on-off valve PC5 is set to the open position. Thus, the wheel cylinder Wfr is connected to the on-off valve P
The brake fluid in the wheel cylinder Wfr flows into the reservoir RS1 and is reduced in pressure by communicating with the reservoir RS1 via C5.

When the wheel cylinder Wfr enters the pulse pressure increasing mode, the open / close valve PC5 is closed and the open / close valve PC1 is opened, and the master cylinder MC receives the master cylinder hydraulic pressure via the open / close valve PC1 in the open position. To the wheel cylinder Wfr. And the on-off valve PC1
Is intermittently controlled, and the brake fluid in the wheel cylinder Wfr is repeatedly increased in pressure and held, increases in a pulsed manner, and is gradually increased. When the rapid pressure increase mode is set for the wheel cylinder Wfr, the open / close valves PC2 and PC5 are set to the closed position, then the open / close valve PC1 is set to the open position, and the master cylinder MC supplies the master cylinder hydraulic pressure.
Then, when the brake pedal BP is released and the master cylinder hydraulic pressure becomes lower than the hydraulic pressure of the wheel cylinder Wfr, the brake fluid in the wheel cylinder Wfr flows through the check valve CV1 and the open / close valve SC1 in the open position. Return to MC, and eventually to low pressure reservoir LRS. In this way, independent braking force control is performed for each wheel.

Then, when the control shifts to traction control, for example, when acceleration slip prevention control of the wheel FR is performed, the on-off valve SC1 is switched to the closed position, and the on-off valve SI1 is switched to the open position. The on-off valve PC2 connected to the on-off position is in the closed position, and the on-off valve PC1 is in the open position. Also, the booster switching valve SB
Is switched to the second position, the auxiliary transformer chamber B6 communicates with the atmosphere, the auxiliary movable wall B5 moves independently of the operation of the brake pedal BP, and the master cylinder MC is driven by boosting. Therefore, the suction side of the hydraulic pump HP1 is filled with the pressurized brake fluid. That is, the brake fluid is sucked from the low-pressure reservoir LRS introduced through the master cylinder MC and the open / close valve SI1 at the open position, and the suction side of the hydraulic pump HP1 is pressurized by the above-described vacuum booster VB. In this state, when the hydraulic pump HP1 is driven by the electric motor M, the pressurized brake fluid is immediately supplied to the wheel cylinder Wfr on the driving wheel side via the on-off valve PC1. If the on-off valve PC1 is in the closed position, the hydraulic pressure of the wheel cylinder Wfr is maintained.

Thus, even when the brake pedal BP is not operated, for example, during acceleration slip prevention control of the wheel FR, the hydraulic pump HP1 is operated by the vacuum booster VB.
Is immediately pressurized, and in this pressurized state, the hydraulic pump HP1 is driven, and the on-off valves PC1, PC5 are intermittently controlled according to the acceleration slip state of the wheel FR, so that the pulse is supplied to the wheel cylinder Wfr. One of the hydraulic modes of pressure increase, pulse pressure reduction, and holding is set. As a result, the braking force is applied to the wheels FR, the rotational driving force is limited, the acceleration slip is prevented, and the traction control can be appropriately performed.

Further, at the time of brake steering control of the vehicle,
In the brake hydraulic system for the wheels FR and RL, the on-off valve SC
1 is switched to the closed position, the on-off valve SI1 is switched to the open position, the electric motor M is driven, and the brake fluid is discharged from the hydraulic pump HP1. And the on-off valve P
The opening and closing of C1, PC2, PC5, and PC6 are controlled as appropriate, and the hydraulic pressure of the wheel cylinders Wfr, Wrl is increased, reduced, or held in pulses, and the brake hydraulic system on the wheels FL, RR is similarly controlled. Thus, the braking force distribution between the front and rear wheels is controlled so that the course traceability of the vehicle can be maintained. Also in this case, similarly to the above, the suction side of the hydraulic pump HP1 is immediately pressurized by the vacuum booster VB, and the control shifts to smooth hydraulic pressure control. In this state,
When the hydraulic pump HP1 is driven by the electric motor M, the pressurized brake fluid is immediately supplied to the wheel cylinder Wfr on the driving wheel side via the on-off valve PC1. For example, in order to prevent excessive oversteer as described above, a braking force is applied to the front wheels on the outside of the turn.

In this embodiment configured as described above, when the ignition switch (not shown) is closed, the execution of the program corresponding to the flowcharts in FIGS. Then, a series of processes such as braking steering control and anti-skid control are performed. FIG. 3 shows the braking control operation of the vehicle. First, in step 101, the microcomputer CMP is initialized and various calculated values are cleared. Next, step 102
, The detection signals of the wheel speed sensors WS1 to WS4 are read, the detection signal of the front wheel steering angle sensor SSf (steering angle δf), the detection signal of the yaw rate sensor YS (actual yaw rate γ), and the detection signal of the lateral acceleration sensor YG ( That is, the actual lateral acceleration is represented by Gya).

Next, the routine proceeds to step 103, where the wheel speed Vw ** of each wheel (** represents each wheel FR etc.) is calculated, and these are differentiated to obtain the wheel acceleration DVw ** of each wheel. Can be Subsequently, in step 104, the maximum value of the wheel speed Vw ** of each wheel is calculated as the estimated vehicle speed Vso at the position of the center of gravity of the vehicle (Vso = MAX (Vw **)). Further, an estimated vehicle speed Vso ** is obtained for each wheel based on the wheel speed Vw ** of each wheel, and if necessary, normalization is performed to reduce an error based on a difference between the inner and outer wheels when the vehicle turns. . Further, the estimated vehicle speed Vso is differentiated, and an estimated vehicle acceleration (including an estimated vehicle deceleration having the opposite sign) DVso at the position of the vehicle center of gravity is calculated.

In step 105, the actual slip ratio of each wheel is determined based on the wheel speed Vw ** of each wheel and the estimated vehicle speed Vso ** (or the normalized estimated vehicle speed) obtained in steps 103 and 104. Sa ** is Sa **
= (Vso **-Vw **) / Vso **. Next, in step 106, based on the estimated vehicle body acceleration DVso at the position of the center of gravity of the vehicle and the actual lateral acceleration Gya detected by the lateral acceleration sensor YG, the road surface friction coefficient μ is approximately (DVso
² + Gya ² ) ^1/2 . Further, as means for detecting the road surface friction coefficient, various means such as a sensor for directly detecting the road surface friction coefficient can be used.

Subsequently, in steps 107 and 108, the body slip angle velocity Dβ is calculated, and the body slip angle β is calculated. The vehicle body slip angle β represents the slip of the vehicle body with respect to the traveling direction of the vehicle as an angle, and can be calculated and estimated as follows. That is, the vehicle body slip angular velocity Dβ is a differential value dβ / dt of the vehicle body slip angle β.
In step 107, Dβ = Gy / Vso−γ can be obtained, which is integrated in step 108 and β = ∫ (Gy / Vso−γ) dt, and the vehicle body slip angle β
Can be requested.

Then, the routine proceeds to step 109, in which a braking steering control mode is set, a target slip ratio to be used for braking steering control is set as described later, and a hydraulic servo control in step 118 described later is performed according to the driving state of the vehicle. The braking force on each wheel is controlled. This braking steering control is superimposed on control in all control modes described later.
Thereafter, the process proceeds to step 110, where it is determined whether or not the anti-skid control start condition is satisfied. If the start condition is satisfied and it is determined that the anti-skid control is to be started at the time of braking steering, the initial specifying control is immediately terminated and step 111 is performed. Is set to a control mode for performing both braking steering control and anti-skid control.

If it is determined in step 110 that the anti-skid control start condition is not satisfied, the process proceeds to step 112, where it is determined whether the front-rear braking force distribution control start condition is satisfied. When it is determined that the braking force distribution control is started, the routine proceeds to step 113, where a control mode for performing both the braking steering control and the longitudinal braking force distribution control is set. Is satisfied or not. If it is determined that the traction control is started during the brake steering control, the control mode is set to perform both the brake steering control and the traction control in step 115, and if neither control is determined to be started during the brake steering control, In step 116, it is determined whether the brake steering control start condition is satisfied.

If it is determined in step 116 that the braking steering control is to be started, the routine proceeds to step 117, where a control mode in which only the braking steering control is performed is set. Then, after performing the hydraulic servo control in step 118 based on these control modes, the process returns to step 102. In the front / rear braking force distribution control mode, the distribution of the braking force applied to the rear wheels to the braking force applied to the front wheels is controlled so as to maintain stability of the vehicle during braking of the vehicle. On the other hand, if it is determined in step 116 that the braking steering control start condition is not satisfied, in step 119, the solenoids of all the solenoid valves are turned off, and the process returns to step 102.
Note that, based on steps 111, 113, 115, and 117, the sub-throttle opening of the throttle control device TH is adjusted according to the operating state of the vehicle, if necessary, and the engine E
The output of G is reduced, and the driving force is limited.

FIG. 4 shows the specific processing for setting the target slip ratio for the brake steering control in step 109 in FIG. 3. The brake steering control includes oversteer suppression control and understeer suppression control. A target slip ratio is set for the wheels according to the oversteer suppression control and / or the understeer suppression control. First, in steps 201 and 202, the start and end of the oversteer suppression control and the understeer suppression control are determined. The start / end determination of the oversteer suppression control performed in step 201 is performed based on whether or not the vehicle is in a control area indicated by oblique lines in FIG.

Thus, the start of the oversteer suppression control
Completion determination is based on the body slip angle β and the body slip angular velocity Dβ
The oversteer suppression control is started when the vehicle enters the control region, and the oversteer suppression control is terminated when the vehicle leaves the control region, and is controlled as indicated by the arrow curve in FIG. . Further, as will be described later, the braking force of each wheel is controlled so that the control amount increases as the distance from the boundary indicated by the two-dot chain line in FIG.

On the other hand, the start / end determination of the understeer suppression control performed in step 202 is made based on whether or not the vehicle is in a control area indicated by oblique lines in FIG. That is, at the time of determination, according to the change of the actual lateral acceleration Gya with respect to the target lateral acceleration Gyt, understeer suppression control is started when the vehicle deviates from the ideal state indicated by the one-dot chain line and enters the control region. Is ended, and control is performed as indicated by the arrow curve in FIG.

Subsequently, it is determined in step 203 whether or not the oversteer suppression control is being controlled. If not, it is determined in step 204 whether or not the understeer suppression control is being controlled. If not, the process returns to the main routine. When it is determined in step 204 that the vehicle is understeer suppression control, the process proceeds to step 205, and the target slip ratio of each wheel is set for understeer suppression control described later. If it is determined in step 203 that the vehicle is in the oversteer suppression control, the process proceeds to step 206 to determine whether or not the vehicle is understeer suppression control. Is set for If it is determined in step 206 that the understeer suppression control is being performed, the oversteer suppression control and the understeer suppression control are performed simultaneously, and in step 208, a target slip ratio for simultaneous control is set.

The target slip ratio of each wheel in step 205 is as follows: the front wheel on the outside of the turn is set to Stufo, the front wheel on the inside of the turn is set to Stufi, and the rear wheel on the inside of the turn is Sturi.
Is set to As for the sign of the slip ratio (S) shown here, "t" represents "target" and represents "actual measurement" described later.
Compared to "a". "u" is "understeer suppression control"
"R" represents "rear wheel", "o" represents "outside", "
i "represents" inside ", respectively.

The target slip ratio of each wheel in step 207 is set to Stefo for the front wheel on the outside of the turn and to Steri for the rear wheel on the inside of the turn. Here, “e” represents “oversteer suppression control”. And step 208
In, the target slip ratio of each wheel is set such that the front wheel on the outside of the turn is set to Stefo, the front wheel on the inside of the turn is set at Stufi, and the rear wheel on the inside of the turn is set at Sturi. That is, when the oversteer suppression control and the understeer suppression control are performed at the same time, the front wheels on the outside of turning are set in the same manner as the target slip ratio of the oversteer suppression control,
The wheels inside the turning are set in the same manner as the target slip ratio of the understeer suppression control. In any case, the rear wheels on the outside of the turn (ie, the driven wheels in the front-wheel drive vehicle) are not controlled because the estimated vehicle speed is set.

The vehicle slip angle β and the vehicle slip angular velocity Dβ are used for setting the target slip ratio for the oversteer suppression control in step 207. However, the target lateral acceleration Gyt is used for setting the target slip ratio for the understeer suppression control. And the actual lateral acceleration Gya.
The target lateral acceleration Gyt is obtained based on Gyt = γ (θf) · Vso. Here, γ (θf) is γ (θf) =
It is obtained as {θf / (N · L)} · Vso / (1 + Kh · Vso ² ), where Kh is a stability factor, N is a steering gear ratio, and L represents a wheelbase.

For example, the target slip ratio Stefo of the front wheel on the outside of the turn used for the oversteer suppression control is Stefo = K
1 · β + K2 · Dβ, and the target slip ratio Steri of the rear wheel inside the turn is set to 0. Here, K1, K
2 is a constant, and the target slip ratio Stefo is set to a value for controlling the pressing direction (direction for increasing the braking force).

On the other hand, the target slip ratio for the understeer suppression control is set as follows based on the deviation ΔGy between the target lateral acceleration Gyt and the actual lateral acceleration Gya. That is,
The target slip ratio Stufo for the front wheel outside the turning is K3
ΔGy is set, and the constant K3 is set to a value for controlling the pressurizing direction (or the depressurizing direction). The target slip ratio Sturi for the rear wheel on the inside of the turn is set to K4 · ΔGy, and the constant K4 is set to a value for controlling the pressing direction. Similarly, the target slip ratio Stufi for the front wheel on the inner side of the turn is set as K5 · ΔGy, and the constant K5 is set to a value for controlling the pressing direction.

FIG. 5 shows the processing of the hydraulic servo control performed in step 118 of FIG. 3. The slip ratio servo control of the wheel cylinder hydraulic pressure is performed for each wheel. First, steps 205, 207 or 20 described above are performed.
The target slip ratio St ** set in step 8 is used in step 30.
1, and these are read as they are as the target slip rates St ** of the respective wheels.

Subsequently, in step 302, the slip ratio deviation ΔSt ** is calculated for each wheel, and in step 303, the vehicle body acceleration deviation ΔDVso ** is calculated.
In step 302, the target slip ratio S of each wheel
The difference between t ** and the actual slip ratio Sa ** is calculated to determine the slip ratio deviation ΔSt ** (ΔSt ** = St ** − Sa *
*). In step 303, the difference between the estimated vehicle acceleration DVso at the position of the center of gravity of the vehicle and the wheel acceleration DVw ** of the wheel to be controlled is calculated, and the vehicle acceleration deviation ΔDV is calculated.
so ** is required. The actual slip ratio S of each wheel at this time
The calculation of a ** and the vehicle body acceleration deviation ΔDVso ** differ depending on the control mode such as anti-skid control, traction control, etc., but the description thereof will be omitted.

Further, the routine proceeds to step 304, where one parameter Y ** used for brake fluid pressure control in each control mode is calculated as Gs ** · (ΔSt ** + IΔSt **). Where Gs ** is a gain, and the vehicle body slip angle β
Is set as shown by the solid line in FIG. Also,
In step 305, another parameter X ** used for brake hydraulic pressure control is calculated as Gd ** · ΔDVso **. The gain Gd ** at this time is a constant value as shown by a broken line in FIG.

Thereafter, the routine proceeds to step 306, where the hydraulic mode is set for each wheel according to the control map shown in FIG. 12 based on the parameters X ** and Y **. In FIG. 12, a rapid pressure reduction region, a pulse pressure reduction region, a holding region,
Each region of the pulse pressure increasing region and the rapid pressure increasing region is set, and it is determined in step 307 which region corresponds to the values of the parameters X ** and Y **. In the non-control state, the hydraulic mode is not set (solenoid off).

If the area determined this time in step 306 is switched from pressure increase to pressure reduction or pressure reduction to pressure increase with respect to the area determined last time, the fall or rise of the brake fluid pressure is made smooth. Since it is necessary, pressure increase / decrease compensation processing is performed in step 307. For example, when switching from the rapid pressure reduction mode to the pulse pressure increase mode, rapid pressure increase control is performed, and the time is determined based on the duration of the immediately preceding rapid pressure reduction mode. Then, step 30
8, opening / closing valve SI * (representing SI1 and SI2), SC
The switching process of * (representing SC1 and SC2) is performed, which will be described later. Then, step 309
In accordance with the hydraulic pressure mode and the pressure increase / decrease compensation processing, the respective on-off valves PC * (PC
1 to PC8) are driven to control the braking force of each wheel.

Next, the switching processing of the on-off valves SI * and SC * performed in step 308 of FIG. 5 will be described with reference to FIG.
This will be described with reference to FIG. First, in step 400, it is determined whether or not automatic pressurization is performed. The automatic pressurization means that the brake fluid pressure is automatically applied to the wheel cylinder by the output fluid pressure of the hydraulic pump in traction control, braking steering control, and the like. Therefore, during the anti-skid control that does not include the brake steering control, the automatic pressurization is not performed, and the routine proceeds to step 411, where the on-off valve SC * is turned off and set to the open position. On the other hand, during automatic pressurization, step 4
01 to 409, the process proceeds to step 410, and the on-off valve S
C * is turned on to be in the closed position, and the electric motor M
Is turned on, and the hydraulic pump HP * (representing HP1 and HP2) is driven.

In step 401, step 30
It is determined whether the hydraulic mode set in 6 is a rapid pressure increase, a pulse pressure increase, a hold, a pulse pressure decrease, or a rapid pressure decrease,
The process proceeds to steps 402 to 406 according to the hydraulic mode.
If the rapid pressure increase mode is set, step 40
From 2, the process proceeds to step 407, where the pressure increase division process is performed. Also, when the pulse pressure increase mode is set, the process proceeds from step 403 to step 407, where the pressure increase division process is performed. It will be described later with reference to FIG.

In the rapid pressure increase mode and the pulse pressure increase mode, the process of limiting the on-off valve SI * is performed in step 409 following step 407. Here, the remaining amount of the brake fluid in the reservoir RS * is compared with the amount of the brake fluid required for the wheel cylinder (the wheel cylinder connected to the reservoir RS *) at that time. If the remaining amount of brake fluid Ar * in the reservoir RS * is larger than the amount of brake fluid required for the wheel cylinder at that time, the on-off valve SI * is turned off and the closed position is set. If the reverse is true, the on-off valve SI * is turned on and is set to the open position. As described above, if the remaining amount Ar * of the brake fluid in the reservoir RS * is larger than the predetermined brake fluid amount, the on-off valve SI * is held in the closed position, and is stored in the reservoir during the fluid pressure control. Brake fluid is also supplied by hydraulic pump HP *
Can be properly discharged.

The remaining amount of brake fluid Ar * in the reservoir RS * is calculated from the sum of (Kfa · ΣTaF *) and (Kra · ΣTaR *) by (K
ma · Mon). That is, A
r * = ｛(KfdΣTdF *) + (KrdΣΣTdR *) − (Km ・ Mo
n)｝ Where Kfd, Krd, and Km are coefficients, ΣTdF *, ΣT
dR * is the pressure reduction time on the front wheel side and the rear wheel side, respectively. Mon is the on time of the electric motor M when the on-off valve SI * is off. In addition, the reference amount of brake fluid is a fixed margin Kz (for example, 1.2) which is the sum of the required brake fluid amount (Kfo · TsF *) on the front wheel side and the required brake fluid amount (Kro · TsR *) on the rear wheel side. Multiplied by Kz · ｛(Kfo · TsF *) + (Kro · Ts
R *) Required as｝. Where Kfo and Kro are coefficients and Ts
F * and TsR * are pressure increase times in the pulse pressure increase mode on the front wheel side and the rear wheel side, respectively, and differ depending on the hydraulic pressure mode.

If the hydraulic mode set in step 306 is any of the holding mode, the pulse depressurizing mode, and the rapid depressurizing mode (that is, if it is not the rapid pressure increasing mode or the pulse pressure increasing mode), step 401 is performed. From step 40
The process proceeds to steps 4, 405 and 406. In step 408, the opening / closing valve SI * is turned off and the valve is closed. Then, the process proceeds from step 408 to step 410, in which the on-off valve SC * is turned on to the closed position, the electric motor M is turned on, and the hydraulic pump HP * is driven, as described above.

FIG. 7 is a flowchart showing the above-described pressure increasing division process, which will be described with reference to the time chart of FIG. First, in step 501, it is determined whether or not immediately after switching to the rapid pressure increase mode or the pulse pressure increase mode,
Otherwise, the process proceeds to step 503. If immediately after switching to the rapid pressure increase mode or the pulse pressure increase mode, the process proceeds to step 502, and the following initial processing is performed at t1 in FIG.

That is, first, the remaining pressure increase time Tr is equal to the total pressure increase time T.
Set to on. Here, the total pressure increase time Ton indicates a required pressure increase time for the wheel cylinder due to the discharge brake hydraulic pressure of the hydraulic pump HP *.
The remainder time (hereinafter, referred to as final discharge time Te) when an integer quotient (K) is obtained by dividing by the time corresponding to the discharge time during the cycle (hereinafter, referred to as pump discharge time Tp), and the quotient is obtained. It can be expressed by the sum of the time of the product (K · Tp) of K and the pump discharge time Tp and the final discharge time Te (Ton = K · Tp + Te). The remaining pressure increase time Tr is the remaining time obtained by subtracting the time during which the pressure increase was performed by the hydraulic pump HP * from the total pressure increase time Ton. Becomes
The required pressure increase time is appropriately set according to the mode of braking control such as braking steering control and brake assist control.

The above-described pump discharge time Tp is equal to the hydraulic pump H
This is determined by the mechanical characteristics of P *, and is the time during which the hydraulic pump HP * during continuous rotation makes one rotation (one cycle) and can actually discharge the brake hydraulic pressure to the wheel cylinder. Accordingly, this can be represented by the open time of the on-off valve PC * in the modulator, which corresponds to the time indicated as "pressure increase" in the modulator time chart in FIG.
The sum of the time of “pressure increase” and the time of “hold” in FIG. 8 is equal to 1 of the hydraulic pump HP *.
This corresponds to the period, and is represented by Ts in FIG. This cycle T
Since s has a fixed relationship with the voltage of the electric motor M as shown in FIG. 9, the voltage of the electric motor M, and thus the discharge amount of the hydraulic pump HP *, can be represented by the time of the cycle Ts.

Further, as an initial process in step 502, the modulator including the on-off valve PC * is held, and the on-off valve SI * for suction is turned on to the open position. At the same time, the suction timer Atm indicating the operation of sucking the brake fluid into the hydraulic pump HP * starts, and the pressure increasing timer Btm indicating the pressure increasing operation on the wheel cylinder by the hydraulic pump HP * is cleared (t1 in FIG. 8). Time).

Next, the routine proceeds to step 503, where it is determined whether or not the pressure increase remaining time Tr is greater than zero. If the remaining pressure increase time Tr is greater than 0, that is, if the required pressure increase time remains, in step 504, the elapsed time of the suction timer Atm is compared with the cycle Ts of the hydraulic pump HP *. If the elapsed time of the suction timer Atm is larger than the cycle Ts,
It means that the elapsed time after the initial processing is longer than the cycle Ts of the hydraulic pump HP *, and the elapsed time from t1 is longer than the hydraulic pump HP * as shown at t2 in FIG. Is longer than the time (cycle Ts) for discharging the brake fluid pressure by one rotation. In this case, step 5
Proceeding to 05, the modulator is set to the pressure increasing state,
The suction timer Atm is cleared, and the pressure increase timer Btm starts (at time t2 in FIG. 8).

If the elapsed time of the suction timer Atm is equal to or shorter than the cycle Ts as in the period between t1 and t2 in FIG. 8, the process proceeds to step 506. This period is the pump discharge time Tp
In some cases, not all are included and only some are included, so that this is excluded from being included in the pressure increase period.

In step 506, the elapsed time of the pressure increase timer Btm started at time t2 in FIG. 8 is the smaller of the pump discharge time Tp and the remaining pressure increase time Tr (=
MIN (Tp, Tr)), and if it is larger than the smaller value, the process proceeds to step 507. Step 50
7, n cycles of the pressure increase remaining time Tr and the pump discharge time Tp (= n · Tp, where n is an integer, and n = n for the first time)
The difference (Tr−n · Tp) of 0, n = K at the last time is set as a new pressure increase remaining time Tr, the modulator is held, and the pressure increase timer Btm is cleared. For example, after time t3 in FIG. 8, the elapsed time of the pressure increase timer Btm from time t2 exceeds the pump discharge time Tp, so that the modulator is held and the pressure increase timer Btm is cleared. I have. FIG. 8 shows an example of K = 1, and when the remaining pressure increase time Tr becomes a value smaller than the pump discharge time Tp, it means the above-mentioned final discharge time Te, which is as shown in FIG.

Since the time after t3 in FIG. 8 is not immediately after the switching to the rapid pressure increasing mode or the pulse pressure increasing mode, the process directly proceeds from step 501 to step 503, where the pressure increasing residual time Tr is larger than 0 and the necessary pressure increasing is performed. If the time remains, the elapsed time of the suction timer Atm is compared with the cycle Ts of the hydraulic pump HP * in step 504. The elapsed time of the suction timer Atm is equal to the period T as shown between the times t3 and t4 in FIG.
If it is equal to or less than s, the process directly proceeds to steps 506 and 507, and the holding state of the modulator is maintained. Suction timer A
If the elapsed time of tm is greater than the cycle Ts, the process proceeds to step 505, where the modulator is set to the pressure increasing state, the suction timer Atm is cleared, and the pressure increasing timer Btm starts (t4 in FIG. 8). Time).

In step 506, the elapsed time of the pressure increase timer Btm started at time t4 in FIG. 8 is the smaller of the pump discharge time Tp and the remaining pressure increase time Tr (= MIN (Tp, Tr)), the modulator returns to the main routine as it is, that is, the modulator remains in the pressure increasing state.
It is determined whether it is greater. In this way, the modulator is in the pressure increasing state from time t4 in FIG. 8 to time t5 when the remaining pressure increase time Tr becomes 0, and when time t5 is reached, the process proceeds from step 503 to step 508, where the modulator is held. At the same time, the suction timer Atm and the pressure increase timer Btm are cleared. Then, the process proceeds to a step 509, wherein the on-off valve SI * is turned off and set to the closed position.

As described above, according to this embodiment, the modulator is kept open during the pump discharge time Tp and the final discharge time Te without leaving it open, and otherwise closed and opened. Since the pressure is controlled so as to repeatedly increase the closed state, the target hydraulic pressure can be reliably obtained, and there is no danger that the brake fluid will flow backward from the modulator side to the hydraulic pump side during the suction cycle of the hydraulic pump. Thus, the various braking controls described above can be performed smoothly and reliably.

[0071]

The present invention has the following effects because it is configured as described above. That is, the vehicle brake control device of the present invention includes a brake fluid pressure control device that discharges the brake fluid of the master cylinder to the wheel cylinder via a modulator by a hydraulic pump, so that the brake fluid pressure of the wheel cylinder is increased. When adjusting the modulator, the hydraulic pump is driven continuously,
With the second on-off valve in the open position, the required pressure increase time for the wheel cylinder is divided by the time corresponding to the discharge time in one cycle of the hydraulic pump to calculate a surplus time when an integer quotient is obtained, Since the modulator is opened and closed for the time corresponding to the discharge time by repeating the number of times of the quotient, and the remainder is opened for the remaining time, the hydraulic pump , And various braking controls can be smoothly and reliably performed.

Further, when the modulator is kept closed for a time corresponding to one cycle of the first hydraulic pump as described in claim 2, one of the hydraulic pumps is provided.
The case where the discharge time during the cycle is not reached is eliminated, and the pressure increase operation by the hydraulic pump for the required pressure increase time can be reliably performed.

Further, when the second on-off valve is configured to be in the closed position after the lapse of the total pressure increasing time, the suction operation to the hydraulic pump is appropriately performed. And the required discharge brake hydraulic pressure can be secured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram according to an embodiment of the present invention.

FIG. 3 is a flowchart showing an entire vehicle braking control according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating a process of setting a target slip ratio used for braking steering control according to the embodiment of the present invention.

FIG. 5 is a flowchart illustrating a hydraulic servo control process according to an embodiment of the present invention.

FIG. 6 shows on-off valves SI * and S in one embodiment of the present invention.
It is a flowchart which shows the switching process of C *.

FIG. 7 is a flowchart illustrating a pressure increase division process according to the embodiment of the present invention.

FIG. 8 is a graph showing an example of the operation states of the on-off valve and the modulator, and the fluctuation states of the suction timer, the pressure increase timer, and the remaining pressure increase time according to the embodiment of the present invention.

FIG. 9 is a graph showing a relationship between a motor voltage and a pump cycle in one embodiment of the present invention.

FIG. 10 is a graph showing an oversteer suppression control start / end determination area according to an embodiment of the present invention.

FIG. 11 is a graph showing an understeer suppression control start / end determination area according to an embodiment of the present invention.

FIG. 12 is a graph showing a relationship between a parameter used for brake hydraulic pressure control and a hydraulic mode in one embodiment of the present invention.

FIG. 13 is a graph showing a relationship between a vehicle body slip angle and a gain for parameter calculation according to an embodiment of the present invention.

[Explanation of symbols]

BP brake pedal, MC master cylinder, M
Electric motor HP1, HP2 hydraulic pump, RS1, RS2 reservoir Wfr, Wfl, Wrr, Wrl Wheel cylinder, FR, F
L, RR, RL wheels, BC brake fluid pressure control device, SC1, SC2 first on-off valve, SI1, SI2
Second on-off valve PC1 to PC8 On-off valve, ECU electronic control unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D046 BB28 BB29 CC02 DD04 EE01 HH08 HH16 HH25 HH36 JJ06 JJ16 LL10 LL23 LL29 LL37 LL47

Claims (3)

[Claims] 1. A brake fluid pressure control device for applying a braking force to at least each wheel of a vehicle according to an operation of a brake pedal, and a braking force applied to each wheel of the vehicle by controlling the brake fluid pressure control device. A braking control means for controlling a vehicle, wherein the brake fluid pressure control device is mounted on each wheel of the vehicle to apply a braking force, and in response to an operation of the brake pedal. A master cylinder that boosts the brake fluid and outputs a master cylinder hydraulic pressure, and connects between the master cylinder and each of the wheel cylinders via a plurality of hydraulic systems, and intervenes in the hydraulic system to perform the braking. A modulator for adjusting the brake fluid pressure of the wheel cylinder in accordance with the control by the control means; and periodically increasing the pressure of the wheel cylinder via the modulator. A hydraulic pump for discharging the brake fluid, a reservoir for storing the brake fluid discharged from the wheel cylinder via the modulator, and a normally open hydraulic circuit for opening and closing a hydraulic passage for connecting and connecting the master cylinder and the modulator. A first on-off valve; and a normally closed second on-off valve for opening and closing a hydraulic path for connecting and connecting the master cylinder to the suction side of the hydraulic pump. When adjusting the modulator to increase the brake fluid pressure, the hydraulic pump is continuously driven, the second open / close valve is set to the open position, and the required pressure increasing time for the wheel cylinder is set to the hydraulic pressure. Calculating the remainder time when an integer quotient is obtained by dividing by the time corresponding to the discharge time in one cycle of the pressure pump,
The modulator is configured to open the modulator for an amount of time corresponding to the ejection time and then to close the modulator by the number of times of the quotient, and to open the modulator for the remainder of the time. Vehicle braking control device. 2. The braking control means controls the modulator for a period corresponding to one cycle of the hydraulic pump immediately after the adjustment of the modulator is started so that the brake hydraulic pressure of the wheel cylinder is increased. The vehicle braking control device according to claim 1, wherein the vehicle braking control device is configured to be maintained in a closed state. 3. The braking control device for a vehicle according to claim 1, wherein the braking control means is configured to set the second on-off valve to a closed position when the total pressure increasing time has elapsed.