JPH0834334A - Brake fluid pressure estimating device in brake traction controller for vehicle - Google Patents

Abstract

PURPOSE:To lessen the error of estimated brake fluid pressure and perform brake traction control precisely by storing the relationship of change gradient to the temperature condition of brake fluid with a variation-of-brake-fluid- pressure operation means, and changing over the change gradient, in accordance with the temperature condition. CONSTITUTION:The CPU of an electronic control unit ECU stores a program which executes antilock control and brake traction control, and each control is performed, according to specified logic. As to the traction control, the ECU stores the relationship of the change gradient of brake fluid pressure to a pressure increase or decrease signal, and operates the variation of brake fluid pressure, based on the pressure increase or decrease signal, and operates this value of the estimated brake fluid pressure, based on the operated variation and the previous value of the estimated brake fluid pressure, and updates this operated value as the previous value of the estimated brake fluid pressured. The ECU stores the relationship of change gradient to the temperature condition of the brake fluid, and changes over the change gradient, in accordance with the temperature condition of the brake fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention of the present application relates to a brake fluid pressure estimating device in a vehicle brake traction control device.

[0002]

2. Description of the Related Art As a conventional device of this type, Japanese Patent Laid-Open No.
85051 and JP-A-5-457.
Those described in Japanese Patent Publication No. 2 are cited.

The one disclosed in Japanese Patent Application Laid-Open No. 2-85051 shuts off the drive wheel brake from the master cylinder by supplying hydraulic fluid to the brake fluid passage extending from the master cylinder to the left and right drive wheel brakes during brake traction control. A high-pressure accumulator with a brake fluid pressure control valve inserted in the hydraulic fluid passage from each actuator to a single high-pressure accumulator that accumulates the hydraulic fluid of this actuator. It supplies and discharges high-pressure hydraulic fluid to each actuator to control the brake fluid pressure of each drive wheel brake.The brake fluid pressure increase time and the pressure decrease time are measured, and the brake fluid pressure is calculated based on the deviation. Presumed.

Further, in the one disclosed in Japanese Patent Laid-Open No. 5-4572, at the time of brake traction control, a brake booster is actuated to turn a master cylinder into a high-pressure brake fluid source, and the left and right drive wheel brakes from the master cylinder. The brake fluid pressure control valve connected to the hydraulic pressure path supplies the high pressure brake fluid from the master cylinder to each drive wheel brake to control the brake fluid pressure of each drive wheel brake. Stores the relationship between the previous value of the estimated brake fluid pressure and the change amount of the brake fluid pressure according to the pressure increase / decrease signal, and based on the previous value of the estimated brake fluid pressure and the pressure increase / decrease signal, the change amount of the brake fluid pressure. Is determined, the current value is determined from the change amount and the previous value, and the current value is updated as the previous value.

Further, in the brake traction control device, for example, as described in Japanese Patent Publication No. 5-65388, the brake fluid in the reservoir is pumped to the left drive wheel brake and the right drive wheel brake to drive each drive wheel. Brake fluid pressure generating means including at least a pump for increasing the brake fluid pressure of the brake and an electric motor for driving the pump, brake fluid inflow from the pump to each of the drive wheel brakes, and each of the drives A plurality of brake fluid pressure control valve means arranged corresponding to each drive wheel brake in order to control the brake fluid outflow from the wheel brakes to the reservoir to independently control the brake fluid pressure of each drive wheel brake; , Outputs a drive signal to the electric motor according to the rotation state of each drive wheel when the vehicle is driven, and causes the brake hydraulic pressure control valve means to Also and control means for preventing idling of the drive wheels and outputs a reduced pressure signal.

[0006]

In any of the above-mentioned brake traction control devices, since the viscosity of the brake fluid greatly differs between the case where the brake fluid temperature is the normal temperature and the case where the brake fluid temperature is the low temperature, when the brake fluid pressure is increased, Since the change gradient at the time of depressurization greatly differs, the conventional technique which does not take this into consideration has a problem that the error of the estimated brake fluid pressure with respect to the actual brake fluid pressure becomes too large.

The invention of this application is intended to solve the above problems.

[0008]

A brake fluid pressure estimating device in a vehicle brake traction control device according to the invention of this application according to the above-mentioned object includes a brake fluid inflow from a brake fluid pressure generating means to a drive wheel brake and the drive. Brake fluid pressure control valve means for controlling the brake fluid outflow from the wheel brake to the reservoir to control the brake fluid pressure of the drive wheel brake, and the brake fluid according to the rotation state of the drive wheel when the vehicle is driven. In a vehicle brake traction control device including a control unit that outputs a pressure increase signal and a pressure decrease signal to a pressure control valve unit to prevent idling of drive wheels, a relationship between a change gradient of brake fluid pressure with respect to the pressure increase / decrease signal is shown. A change amount calculating means for storing a change amount calculating means for calculating a brake fluid pressure change amount based on the pressure increase / decrease signal, and a change amount calculating means for calculating the change amount. This time value calculating means for calculating the current value of the estimated brake hydraulic pressure based on the change amount of the brake hydraulic pressure and the previous value of the estimated brake hydraulic pressure, and the current value calculated by the current value calculating means for the estimated brake hydraulic pressure. The change amount calculating means stores a relationship of the change gradient with respect to the temperature state of the brake fluid, and the change amount calculation means stores the change gradient corresponding to the temperature state of the brake fluid. It is to switch.

The temperature condition of the brake fluid may be detected by a sensor that directly detects the brake fluid temperature, or may be determined by detecting a physical quantity closely related to the brake fluid temperature. When divided into two, it can be determined by the idling speed of the vehicle engine (since the idling speed is higher at low temperature than at room temperature).

[0010]

In the brake fluid pressure estimating device having the above-described structure, the brake fluid pressure change amount calculation means switches the change gradient of the brake fluid pressure to the change gradient corresponding to the temperature state of the brake fluid to calculate the change amount. Therefore, the error of the estimated change amount with respect to the actual change amount is reduced, and the error of the estimated brake fluid pressure is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a brake fluid pressure estimating device in a brake traction control device according to the invention of this application will be described with reference to the drawings.

FIG. 1 shows the overall construction of an antilock control device and a brake traction control device for an FR vehicle (front engine / rear drive vehicle). One pressure chamber of the tandem type master cylinder MC driven by the brake pedal BP is connected to the left rear wheel brake RL, which is a drive wheel brake, via the normally open electromagnetic cutoff valve SIRL, and the normally open electromagnetic cutoff valve SIRR. It is connected to the right rear wheel brake RR, which is a drive wheel brake, respectively. The left rear wheel brake RL and the right rear wheel brake RR are connected to the low pressure reservoir R1 via a normally closed electromagnetic cutoff valve SORL and a normally closed electromagnetic cutoff valve SORR, respectively. A suction port of a pump P1 driven by an electric motor M is connected to the low pressure reservoir R1 via a check valve CV1.
The discharge port of No. 1 is connected to one pressure chamber of the master cylinder MC via the damper chamber D1 having a fixed volume for damping the pump discharge pulsation and the orifice O1, the electromagnetic cutoff valve SIRL and the electromagnetic cutoff valve SI.
It is connected to the brake fluid passage that connects to RR. The check valve CV2 that allows only the flow of brake fluid from the left rear wheel brake RL side to the master cylinder MC side is the electromagnetic shutoff valve S.
A check valve CV3 that is arranged in parallel with the IRL and allows only the flow of brake fluid from the right rear wheel brake RR side to the master cylinder MC side is arranged in parallel with the electromagnetic cutoff valve SIRR.

The other pressure chamber of the master cylinder MC is connected to a left front wheel brake FL which is a driven wheel brake through a normally open electromagnetic cutoff valve SIFL, and a right wheel which is a driven wheel brake via a normally open electromagnetic cutoff valve SIFR. Each is connected to the front wheel brake FR. The left front wheel brake FL and the right front wheel brake FR are connected to a low pressure reservoir R2 via a normally closed electromagnetic shutoff valve SOFL and a normally closed electromagnetic shutoff valve SOFR, respectively.
It is connected to the. A suction port of a pump P2 driven by an electric motor M is connected to the low-pressure reservoir R2, and a discharge port of the pump P2 of the master cylinder MC via a damper chamber D2 having a fixed volume for damping pump discharge pulsation and an orifice O2. On the other hand, it is connected to a brake fluid passage that connects the pressure chamber to the electromagnetic shutoff valve SIFL and the electromagnetic shutoff valve SIFR. A check valve CV4 that allows only the flow of brake fluid from the left front wheel brake FL side to the master cylinder MC side is arranged in parallel with the electromagnetic cutoff valve SIFL, and only the brake fluid flow from the right front wheel brake FR side to the master cylinder MC side. The check valve CV5 that allows the solenoid valve is arranged in parallel with the electromagnetic shutoff valve SIFR.

In order to perform brake traction control,
One pressure chamber of master cylinder MC and solenoid cutoff valve SIRL
A normally open electromagnetic cutoff valve SMC is provided at a position on the master cylinder side of the brake fluid passage connecting the electromagnetic cutoff valve SIRR and the discharge brake fluid of the pump P1. Then, when the hydraulic pressure in the brake fluid passage connecting the electromagnetic shutoff valve SMC to the electromagnetic shutoff valve SIRL and the electromagnetic shutoff valve SIRR abnormally rises, the safety valve S that releases the brake fluid in the hydraulic fluid passage to the master cylinder side.
V is arranged in parallel with the electromagnetic cutoff valve SMC. Furthermore,
The suction port of the pump P1 is connected to the master cylinder reservoir MCR via a normally closed electromagnetic cutoff valve SSC, and the electromagnetic cutoff valve SMC, the electromagnetic cutoff valve SIRL, and the electromagnetic cutoff valve SIRR are connected.
The brake fluid passage that connects the
And the pressure limiting valve RV in this order, and is connected to the brake fluid passage that connects the electromagnetic cutoff valve SSC and the suction port of the pump P1.

Both the pump P1 and the pump P2 have a built-in suction valve and discharge valve. The opening pressure of the suction valve of the pump P2 is higher than the atmospheric pressure, whereas the pump P1.
The valve opening pressure of the suction valve is lower than atmospheric pressure. The valve opening pressure of the check valve CV1 is higher than the valve opening pressure of the suction valve of the pump P1.

Further, the pump P1, the electric motor M, the electromagnetic shutoff valve SMC, the electromagnetic shutoff valve SSC, the electromagnetic shutoff valve SRC, the pressure limiting valve RV, the safety valve SV, and the check valve CV1 are the brake fluid pressure generating means in claim 1. Comprising a solenoid cutoff valve SIRL,
The electromagnetic shutoff valve SORL, the electromagnetic shutoff valve SIRR, and the electromagnetic shutoff valve SORR constitute the brake fluid pressure control valve means in claim 1.

With the above structure, the electric motor M is energized to prevent the left rear wheel, the right rear wheel, the left front wheel, and the right front wheel from being locked during vehicle braking, and the electromagnetic cutoff valve SIRL, the electromagnetic cutoff valve SIRR, and the electromagnetic cutoff are provided. Valve SIFL, solenoid cutoff valve SIFR
By controlling the energization / de-energization of each solenoid, the brake fluid pressures of the left rear wheel brake RL, the right rear wheel brake RR, the left front wheel brake FL, and the right front wheel brake FR are individually reduced, maintained and increased. Lock control can be performed. When the vehicle starts or accelerates, the motor M, the electromagnetic cutoff valve SMC, the electromagnetic cutoff valve SSC, and the electromagnetic cutoff valve SRC are energized to prevent the left rear wheel and the right rear wheel from idling and the electromagnetic cutoff valve SIRL is turned on. The left rear wheel brake R is controlled by energizing or deenergizing the solenoids of the solenoid shutoff valve SIRR, the solenoid shutoff valve SIFL, and the solenoid shutoff valve SIFR.
L, increase the brake fluid pressure of the right rear wheel brake RR individually,
Brake traction control for controlling pressure holding and pressure reduction can be performed.

For example, when the vehicle is being braked, the electric motor M is energized, and the solenoid of the electromagnetic cutoff valve SIRL and / or the solenoid cutoff valve SIRR and the electromagnetic cutoff valve SOR are controlled.
When the solenoid of L and / or the electromagnetic shut-off valve SORR is energized, the brake fluid of the left rear wheel brake RL and / or the right rear wheel brake RR is discharged to the low pressure reservoir R1 and the left rear wheel brake RL and / or the right rear wheel. Brake R
The brake fluid pressure of R is reduced. The brake fluid flowing out to the low pressure reservoir R1 is transferred to the master cylinder M by the pump P1.
It recirculates to a brake fluid passage that connects one pressure chamber of C to the electromagnetic cutoff valve SIRL and the electromagnetic cutoff valve SIRR. By deenergizing the solenoid of the electromagnetic shutoff valve SIRL and / or the solenoid shutoff valve SIRR and the solenoid of the electromagnetic shutoff valve SORL and / or the solenoid shutoff valve SORR,
Brake fluid from one pressure chamber of the master cylinder and the pump P1 is supplied to the left rear wheel brake RL and / or the right rear wheel brake RR to increase the brake fluid pressure of the left rear wheel brake RL and / or the right rear wheel brake RR. Is pressed.
Further, the electromagnetic shutoff valve SIRL and / or the electromagnetic shutoff valve S
While energizing the solenoid of IRR, solenoid shutoff valve SOR
If the solenoid of L and / or the electromagnetic shut-off valve SORR is de-energized, the brake fluid is prevented from entering and leaving the left rear wheel brake RL and / or the right rear wheel brake RR, and the left rear wheel brake RL and / or the right rear wheel brake. RR
The brake fluid pressure is maintained.

Similarly, when the vehicle is being braked, the electric motor M is energized, and the solenoid of the solenoid cutoff valve SIFL and / or the solenoid cutoff valve SIFR and the solenoid cutoff valve SOF are set.
By energizing the solenoid of L and / or the electromagnetic cutoff valve SOFR, the brake fluid of the left front wheel brake FL and / or the right front wheel brake FR is discharged to the low pressure reservoir R2, and the left front wheel brake FL and / or the right front wheel brake F is released.
The brake fluid pressure of R is reduced. The brake fluid flowing out to the low pressure reservoir R1 is transferred to the master cylinder M by the pump P1.
It is returned to the brake fluid passage connecting the other pressure chamber of C with the electromagnetic shutoff valve SIFL and the electromagnetic shutoff valve SIFR. By deenergizing the solenoid of the solenoid cutoff valve SIFL and / or the solenoid cutoff valve SIFR and the solenoid of the solenoid cutoff valve SOFL and / or the solenoid cutoff valve SOFR,
Brake fluid from one pressure chamber of the master cylinder and the pump P2 is supplied to the left front wheel brake FL and / or the right front wheel brake FR to increase the brake fluid pressure of the left front wheel brake FL and / or the right front wheel brake FR.
Further, the electromagnetic shutoff valve SIFL and / or the electromagnetic shutoff valve S
While energizing the solenoid of IFR, solenoid shutoff valve SOF
If the solenoid of L and / or the electromagnetic shutoff valve SOFR is de-energized, the brake fluid is prevented from flowing in and out of the left front wheel brake FL and / or the right front wheel brake FR, and the left front wheel brake FL and / or the right front wheel brake FR.
The brake fluid pressure is maintained.

When starting or accelerating the vehicle, the electric motor M
And electromagnetic shutoff valve SMC, electromagnetic shutoff valve SSC, electromagnetic shutoff valve S
When RC is energized, the pump P1 draws in the brake fluid from the master cylinder reservoir MCR and discharges it into the brake fluid passage connecting the electromagnetic shutoff valve SMC, the electromagnetic shutoff valve SIRL, and the electromagnetic shutoff valve SIRR to the brake fluid passage. The applied brake fluid is supplied to the left rear wheel brake RL through the electromagnetic cutoff valve SIRL and is also supplied to the right rear wheel brake RR through the electromagnetic cutoff valve SIRR, so that the brake fluid pressures of the left rear wheel brake RL and the right rear wheel brake RR are increased. Are increased at the same time. At that time, if the electromagnetic cutoff valve SIRL or the electromagnetic cutoff valve SIRR is energized, all the brake fluid discharged from the pump P1 is supplied to the right rear wheel brake RR or the left rear wheel brake RL, and the right rear wheel brake RR or the left rear wheel brake RR. The brake fluid pressure of the wheel brake RL is increased with a pressure increase gradient that is larger than the pressure increase gradient when the brake fluid pressures of the left rear wheel brake RL and the right rear wheel brake RR are simultaneously increased. FIG. 2 shows that the brake fluid pressure is increased by pumping the brake fluid to the left rear wheel brake (or the right rear wheel brake) by the pump P1 in a stable operation state at each of the room temperature and the low temperature of the brake fluid temperature. The change of the brake fluid pressure with respect to time is shown. Further, while energizing the solenoid of the solenoid cutoff valve SIRL and / or the solenoid cutoff valve SIRR, the solenoid cutoff valve SORL and / or the solenoid cutoff valve SO
When the solenoid of the RR is energized, the brake fluid of the left rear wheel brake RL and / or the right rear wheel brake RR is discharged to the low pressure reservoir R1, and the brake fluid pressure of the left rear wheel brake RL and / or the right rear wheel brake RR is increased. The pressure is reduced.
Further, the electromagnetic cutoff valve SIRL and / or the electromagnetic cutoff valve S
While energizing the solenoid of IRR, solenoid shutoff valve SOR
If the solenoid of L and / or the electromagnetic shut-off valve SORR is de-energized, the brake fluid is prevented from entering and leaving the left rear wheel brake RL and / or the right rear wheel brake RR, and the left rear wheel brake RL and / or the right rear wheel brake. RR
The brake fluid pressure is maintained.

Solenoid valve cutoff valve SIRL, solenoid valve cutoff valve SI
RL, solenoid valve shutoff valve SORL, solenoid valve shutoff valve SORL,
The solenoid valve shutoff valve SIFL, solenoid valve shutoff valve SIFL, solenoid valve shutoff valve SOFL, solenoid valve shutoff valve SOFL, solenoid valve shutoff valve SMC, solenoid valve shutoff valve SSC, solenoid valve shutoff valve SRC are connected to an electronic control unit ECU, Energization and de-energization of each solenoid are controlled. The electric motor M is also an electronic control unit E
It is connected to and controlled by the CU. Further, wheel speed sensors SE1 to SE4 are respectively arranged on the left rear wheel, the right rear wheel, the left front wheel, and the right front wheel, and these are electronic control devices E.
It is connected to the CU and is configured so that the rotation speed of each wheel, that is, the wheel speed signal is input to the electronic control unit ECU.

As shown in FIG. 3, the electronic control unit ECU includes a microcomputer having a CPU, a ROM, a RAM and the like, which is connected to an input interface and an output interface via a common bus to perform input / output with the outside. There is. Detection signals of the wheel speed sensors SE1 to SE4 are input to the CPU from the input interface via the amplifier circuits AMP1 to AMP4. Then, in order to determine whether or not the brake fluid temperature is low, an engine idle speed signal EIN from an engine controller (not shown) is input to the CPU from the input interface. From the output interface, drive circuits Da to D
solenoid valve shutoff valve SIRL, solenoid valve shutoff valve SIRL, solenoid valve shutoff valve SORL, solenoid valve shutoff valve SO
RL, solenoid valve shutoff valve SIFL, solenoid valve shutoff valve SIFL,
Solenoid valve shutoff valve SOFL, solenoid valve shutoff valve SOFL, solenoid valve shutoff valve SMC, solenoid valve shutoff valve SSC, solenoid valve shutoff valve SR
The control signal is output to C and the control signal is output to the electric motor M via the drive circuit Dm. Electronic control unit E
The CPU of the CU stores a program that executes antilock control and brake traction control,
Although the anti-lock control and the brake traction control are performed according to a predetermined logic, the anti-lock control is not directly related to the invention of this application, so the description thereof will be omitted. ~ It demonstrates below with reference to FIG.

4 and 5 show the processing procedure of the main routine. In FIG. 4, first, in step S1, the wheel speeds of the left rear wheel, the right rear wheel, the left front wheel, and the right front wheel are sequentially calculated, and when the wheel speed calculation of the four wheels is completed, the process proceeds to step 2. In step 2, the estimated vehicle body speed is calculated based on the wheel speeds of the left front wheel and the right front wheel, and the process proceeds to step S3. In step S3, the brake control start determination reference wheel speed, the brake control end determination reference wheel speed, and the brake fluid pressure increase determination reference wheel speed are based on the estimated vehicle body speed and the four slip ratio predetermined values. , The reference wheel speed for determining the brake fluid pressure reduction is sequentially calculated, and step S
Go to 4. In step S4, the wheel acceleration of the left rear wheel and the wheel acceleration of the right rear wheel are sequentially calculated, and the process proceeds to step S5.
In step S5, the left rear wheel is selected and the process proceeds to step S6. In step S6, the RL brake control in-progress flag is 1 (RL brake control in-progress flag = 1 indicates that the left rear wheel brake is in brake control). Whether or not it is determined, and if the determination result is No, the process proceeds to step S7. In step S7, it is determined whether to start the RL brake control. The condition for starting the RL brake control is that the wheel speed of the left rear wheel becomes equal to or higher than the reference wheel speed for brake control start determination. If the determination result in step S7 is Yes, the RL brake control flag is set to 1 in step S8, and the process proceeds to step S9. In step S9, the electric motor M, the electromagnetic cutoff valve SMC, the electromagnetic cutoff valve SS
C and the electromagnetic cutoff valve SRC are energized, then the process proceeds to step S10, the RL brake control is executed, the RL pressure increase / decrease time is returned to 0 in step S11, and the measurement of the RL pressure increase / decrease time is started. To step S19.

If the result of the determination in step S6 is No, the process proceeds to step S12, and in step S12 R
After the estimation of the L brake hydraulic pressure, it is determined in step S13 whether or not to terminate the RL brake control. RL
The condition for ending the brake control is that the wheel speed is less than the reference wheel speed for judging the brake control end and the RL estimated brake hydraulic pressure is 0. If the decision result in the step S13 is YES, the RL brake control flag, the RL pressure reducing flag and the RL gentle pressure reducing flag are set to 0 in a step S14, and then the RR is performed in a step S15.
It is determined whether or not the brake control flag is 0, and if the determination result is Yes, in step S16, the electric motor M, the electromagnetic cutoff valve SMC, the electromagnetic cutoff valve SSC, the electromagnetic cutoff valve SRC, and the electromagnetic cutoff valve SIRL. And solenoid shutoff valve SOR
L is de-energized, the RL pressure increase / decrease time is returned to 0 in step S17, and then the process proceeds to step S19. If the determination result in step S15 is No, step S15
At 18, the electromagnetic shut-off valve SIRL is energized while the electromagnetic shut-off valve SORL is de-energized, and then the process proceeds to step S17. If the determination result in step S13 is No, the process returns to step S10.

In FIG. 5, the right rear wheel is selected in step S19, and the process proceeds to step S20. In step S20, it is determined whether or not the RR brake control flag is 1, and if the determination result is No, It proceeds to step S21. In step S21, it is determined whether to start the RR brake control. The conditions to start the brake control are
That is, the wheel speed of the right rear wheel is equal to or higher than the reference wheel speed for the brake control start determination. If the determination result in step S21 is Yes, the RR brake control flag is set to 1 in step S22, and the process proceeds to step S22. In step S23, the electric motor M, the electromagnetic cutoff valve SMC, the electromagnetic cutoff valve SSC, and the electromagnetic cutoff valve SRC are energized, then the RR brake control is executed in step S24, and the RR pressure increase / decrease time is returned to 0 in step S25. The measurement of the RR increase / decrease time is started, and then the process returns to step S1 in FIG. 4 to end one cycle.

Further, the determination result in step S20 is No.
In this case, the process proceeds to step S26, and after the RR brake hydraulic pressure estimation is performed in step S26, it is determined in step S27 whether or not to terminate the RR brake control. R
The condition for ending the R brake control is that the wheel speed is less than the reference wheel speed for judging the brake control end and the RR estimated brake hydraulic pressure is 0. If the decision result in the step S27 is YES, in a step S28, the brake control flag, the RR pressure reducing flag and the RR slow pressure reducing flag are set to 0, and then the RL brake control flag is 0 in a step S29. It is determined whether or not there is, and when the determination result is Yes, in step S30, the electric motor M, the electromagnetic cutoff valve SMC, the electromagnetic cutoff valve SSC, the electromagnetic cutoff valve SRC, the electromagnetic cutoff valve SIRL, and the electromagnetic cutoff valve SORL.
Is de-energized, and after the RR pressure increasing / decreasing time is returned to 0 in step S31, the process returns to step S1 in FIG. If the determination result in step S29 is No, step S29
At 32, the electromagnetic cutoff valve SIRL is energized while the electromagnetic cutoff valve SORL is deenergized, and then the process proceeds to step S31.

Details of step S10 are shown in FIG. Figure 6
In step S10a, it is determined whether or not the brake fluid pressure is to be increased by referring to the map stored in the ROM on the basis of the pressure increase determination reference wheel speed and the wheel acceleration. If the determination result is Yes, step S1
At 0b, it is determined whether the estimated brake fluid pressure is equal to or higher than a predetermined value. If the determination result is Yes, step S
At 10c, the RL gradually increasing pressure flag is set to 1, and at the same time, the RL increasing pressure flag, the RL reducing pressure flag, the RL gradually reducing pressure flag, and the RL holding pressure flag are set to 0, and then at step S10d, The electromagnetic shutoff valve SORL is deenergized at the same time as the electromagnetic shutoff valve SORL is energized in a pulsed manner at a predetermined time interval for a predetermined time. If the determination result in step S10b is No, the process proceeds to step S10e, the RL pressure increasing flag is set to 1, and the RL slowly increasing pressure flag, RL depressurizing flag, RL are set.
The in-slow depressurization flag and the RL in-pressure holding flag are set to 0, and then, in step S10f, the electromagnetic cutoff valve SIRL and the electromagnetic cutoff valve SORL are de-energized, and then the process ends. The reason why the pressure is gradually increased when the estimated brake fluid pressure is equal to or higher than the predetermined value is to maintain the vehicle acceleration feeling.

If the result of the determination in step S10a is No, in step S10g the brake fluid pressure is reduced by referring to the map stored in the ROM based on the reference wheel speed for pressure reduction determination and the wheel acceleration. It is determined whether or not.
If the determination result is Yes, it is determined in step S10i whether or not the pressure increase time is equal to or greater than a predetermined value. If the determination result is Yes, the RL depressurizing flag is set to 1 in step S10j. RL pressure increasing flag, RL gentle pressure increasing flag, RL gentle pressure reducing flag and R
The L pressure holding flag is set to 0, and then step S1
Solenoid shutoff valve SIRL and solenoid shutoff valve SORL at 0k
Is turned on, and then ends. If the decision result in the step S10i is No, the RL gradually decreasing pressure flag is set to 1 and the RL increasing pressure flag, the RL slowly increasing pressure flag, the RL decreasing pressure flag and the R
The L pressure holding flag is set to 0, and then step S1
At 0n, the electromagnetic cutoff valve SIRL is energized and the electromagnetic cutoff valve SORL is energized in a pulsed manner, and then the process ends. If the determination result in step S10g is No, the RL pressure maintaining flag is set to 1 in step S10o, and the RL pressure increasing flag, the RL slow pressure increasing flag, R
The L depressurizing flag and the RL gentle depressurizing flag are set to 0, and then in step S10p, the electromagnetic shutoff valve SIRL is set.
Is energized and the electromagnetic shut-off valve SORL is de-energized, and then the process ends.

The details of the RR brake control in step S24 are the contents in which RL, SIRL, and SORL are read as RR, SIRR, and SORR in FIG. 6, respectively.

Details of step S12 are shown in FIGS. In FIG. 7, first, in step S1201, RL is set.
It is determined whether or not the pressure-increasing flag is 1, and if the determination result is Yes, it is determined whether or not the RR pressure-increasing flag is 1 in step S1202, and the determination result is Yes. In this case, it is determined in step S1203 whether or not the brake fluid temperature is in a low temperature state (when the engine idle speed is equal to or higher than a predetermined speed), and the determination result is N.
If it is o, the change gradient WC is set to the predetermined value WC1 in step S1204, and if the determination result in step S1203 is Yes, the change gradient WC is set to the predetermined value WC2 in step S1205. Step S1
Proceed to 231.

If the determination result in step S1202 is No, it is determined in step S1206 whether or not the RR slowly increasing pressure flag is 1, and if the determination result is no, the brake is performed in step S1207. It is determined whether or not the liquid temperature is in a low temperature state. If the determination result is No, the change gradient WC is the predetermined value WC3 in step S1208.
After being set to, the process proceeds to step S1231. If the determination result in step S1206 is Yes, it is determined in step S1210 whether the brake fluid temperature is in the low temperature state. If the determination result is No, the change gradient WC is determined in step S1211. After the predetermined value WC5 is set, the process proceeds to step S1231. If the determination result in step S1210 is Yes, the change gradient WC is set to a predetermined value WC6 in step S1212, and then step S1210 is performed.
Proceed to 1231.

If the determination result in step S1201 is No, the process proceeds to step S1213 in FIG.
In 1213, it is determined whether or not the RL slowly increasing pressure flag is 1, and if the determination result is Yes, step S1.
At 214, it is determined whether or not the RR pressure increasing flag is 1, and if the determination result is Yes, step S in FIG.
Proceed to 1210. If the determination result in step S1214 is N
If o, it is determined in step S1215 whether or not the RR slowly increasing pressure flag is 1, and if the determination result is No, it is determined in step S1216 whether the brake fluid temperature is in a low temperature state. Is determined, and if the determination result is No, the change gradient WC is the predetermined value W in step S1217.
After being set to C7, the process proceeds to step S1231 in FIG. 7, and if the determination result in step S1216 is Yes, the change gradient WC is set to the predetermined value W in step S1218.
After being set to C8, the process proceeds to step S1231 in FIG. If the determination result in step S1215 is Yes, it is determined in step S1219 whether or not the brake fluid temperature is in the low temperature state, and if the determination result is No, the change gradient WC is a predetermined value in step S1220. After being set to WC9, the process proceeds to step S1231 in FIG. 7, and if the determination result in step S1219 is Yes, the change gradient WC is set to the predetermined value WC10 in step S1221, and then step S1231 in FIG. Go to. If the determination result in step S1213 is No, it is determined in step S1222 whether the RL depressurizing flag is 1, and if the determination result is Yes, step S1
At 223, it is determined whether the brake fluid temperature is in a low temperature state. If the determination result is No, step S12
After the change gradient WC is set to the predetermined value WC11 at 24, the process proceeds to step S1231 of FIG. 7 and step S12.
If the determination result in No. 22 is No, step S1225
After the change gradient WC is set to the predetermined value WC12 in, the process proceeds to step S1231 in FIG. If the determination result in step S1222 is No, in step S1226 R
It is determined whether or not the L slow depressurizing flag is 1, and if the determination result is Yes, it is determined in step S1227 whether or not the brake fluid temperature is in the low temperature state, and the determination result is No. In this case, after the change gradient WC is set to the predetermined value WC13 in step S1228, the process proceeds to step S1231 in FIG. 7, and if the determination result in step S1227 is No, the change gradient WC is calculated in step S1229.
Is set to a predetermined value WC14, and then step S1 in FIG.
Proceed to 231. The determination result in step S1226 is No.
In this case, after the change gradient WC is set to 0 in step S1230, the process proceeds to step S1231 in FIG.

In step S1231, the change amount ΔWC of the brake fluid pressure is calculated by the set change gradient WC and the pressure increasing / decreasing time, and in step S1232, the current value of the estimated brake fluid pressure is added to the previous value by the change amount ΔWC. Then, the current value is updated as the previous value in step S1233.

The change gradients WC1 to WC10 are positive (pressure increasing side)
Change gradient of WC11 to WC14 is negative (decompression side)
Is the change gradient of. Of the change gradients WC1 to WC10,
WC1 and WC2 are change gradients when increasing the pressure of the left rear wheel brake and the right rear wheel brake at the same time, and WC5 and WC6 are change gradients when increasing only one of the left rear wheel brake and the right rear wheel brake. Yes, WC3 and WC4 are change gradients when one of the left rear wheel brake and the right rear wheel brake is pressure-increased while the other is slowly increased, and WC7 and WC8 are the left rear wheel brake and the right rear wheel brake. It is a change gradient when only one of the brakes is gradually increased, and WC9 and WC10 are change gradients when the left rear wheel brake and the right rear wheel brake are simultaneously slowly increased. This is to supply the discharge brake fluid of the single pump P1 to the left rear wheel brake RL and / or the right rear wheel brake RR, and to increase the pressure of each of the left rear wheel brake RL and the right rear wheel brake RR. This is due to the setting of pressure (rapid pressure increase) and slow pressure increase. WC1> WC2, WC
3> WC4, WC5> WC6, WC7> WC8, WC9
> WC10.

The details of step S26 in FIG. 5 are the contents obtained by replacing RL and RR with RR and RL in FIGS. 7 and 8, respectively.

As shown in FIGS. 7 and 8, when calculating the pressure increase side change amount in the estimation of the brake fluid pressure, when the brake fluid temperature is room temperature, WC1, WC3,
WC5, WC7, WC9, WC11, or WC14 is used, and when the brake fluid temperature is low, WC
2, WC4, WC6, WC8, WC10, WC12, W
The calculation is performed using any one of C13, and the error of the estimated value of the brake fluid pressure with respect to the actual value is reduced, so that the brake traction control can be accurately ended.

The embodiment of the brake fluid pressure estimating device in the vehicle brake traction control device according to the invention of this application has been described above. However, the brake fluid pressure source and the brake fluid pressure control valve means for the brake traction control are explained. The specific low configuration is not limited to the configuration of FIG. 1 and can be changed as appropriate.

Also, the logic of the brake clutch control is not limited to those shown in FIGS. 4 and 5, but can be changed as appropriate.

Further, the number of divisions of the temperature state of the brake fluid is not limited to two, and for example, the number of divisions of the temperature state of the brake fluid may be set to three or more and corresponding three or more change gradients may be selected. Good. In the configuration in which the brake fluid is pumped to the drive wheel brakes by the motor-driven pump to increase the pressure, the change gradient changes depending on the motor operating voltage, and the change gradient when the brake fluid pressure increases is the pump operation after the motor starts operating. The change gradient changes until the brake pressure stabilizes, and the pressure increase gradient when calculating the change amount of the brake fluid pressure also depends on the motor operating voltage, the temperature state of the brake fluid, and the elapsed time from the start of control. By doing so, the error in the estimated brake fluid pressure can be further reduced.

[0040]

As described above in detail, according to the invention of this application, the brake fluid inflow from the brake fluid pressure source to the drive wheel brake and the brake fluid outflow from the drive wheel brake to the reservoir are controlled. To output a pressure increase signal and a pressure decrease signal to the brake fluid pressure control means for controlling the brake fluid pressure of the drive wheel brake, and the brake fluid pressure control means according to the rotation state of the drive wheels when the vehicle is driven. Therefore, it is possible to reduce the error of the estimated brake fluid pressure in the vehicle brake traction control device including the control means for preventing the drive wheels from idling, and to perform the brake traction control accurately.

[Brief description of drawings]

FIG. 1 is a brake fluid pressure path diagram of an embodiment of the invention of this application.

FIG. 2 is a diagram showing changes in brake fluid pressure increase at normal temperature and at low temperature.

FIG. 3 is a diagram showing a configuration of the electronic control device of FIG.

FIG. 4 is a first half portion of a flowchart showing a process of a main routine of an embodiment of the invention of this application.

FIG. 5 is the latter half of the flowchart showing the processing of the main routine of one embodiment of the invention of this application.

FIG. 6 is a flowchart showing details of step S10 in FIG.

7 is a part of a flowchart showing details of step S12 in FIG.

8 is the rest of the flowchart showing the details of step S12 in FIG.

[Explanation of symbols]

MC: Master cylinder SIRL, SIRR, SORL, SORR, SMC, S
SC, SRC ... Electromagnetic shutoff valve R1 ... Low pressure reservoir P1 ... Pump M ... Electric motor SV ... Safety valve RV ... Pressure limiting valve ECU ... Electronic control device SE1, SE2, SE3, SE4 ... Wheel speed sensors

Claims (1)

[Claims] 1. A brake fluid for controlling the brake fluid pressure of the drive wheel brake by controlling the brake fluid inflow from the brake fluid pressure generating means to the drive wheel brake and the brake fluid outflow from the drive wheel brake to the reservoir. Pressure control valve means and control means for outputting a pressure increase signal and a pressure decrease signal to the brake fluid pressure control valve means according to the rotation state of the drive wheels when the vehicle is driven to prevent the drive wheels from idling. In a vehicle brake traction control device, a change amount calculating means for storing a relationship of a change gradient of a brake hydraulic pressure with respect to the pressure increasing / decreasing signal and calculating a brake hydraulic pressure change amount based on the pressure increasing / decreasing signal, and the change amount. A current value calculation means for calculating a current value of the estimated brake fluid pressure based on a change amount of the brake fluid pressure calculated by the calculation means and a previous value of the estimated brake fluid pressure; The change amount calculating means stores the relationship of the change gradient with respect to the temperature state of the brake fluid, and the updating means for updating the current value calculated by the time value calculating means as the previous value of the estimated brake fluid pressure. A brake fluid pressure estimating device in a vehicle brake traction control device, wherein the change gradient is switched according to a temperature state of the brake fluid.