JP2000177567A - Brake controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a response delay by a change in a working fluid temperature when controlling braking pressure by pressure generated by a braking pressure generating means. SOLUTION: A master cylinder 1 and a braking pressure generating circuit 9 are selected by solenoid directional control valves 4FL to 4RR to be connected to wheel cylinders 6FL to 6RR, and in a state of selecting the braking pressure generating circuit 9, braking pressure to the wheel cylinders is generated by controlling pressure control valves 16FL to 16RR according to operation quantity of a brake pedal 2. At this time, a working fluid temperature estimative value is calculated from the elapsed time required for changing a working fluid temperature by increase/decrease quantity or prescribed increase/decrease quantity per unit time in an accumulator 9 at nonbraking time, and when this working fluid temperature estimative value is not more than a prescribed value, a correction value is added to target braking pressure during a prescribed time to restrain a response delay.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device which performs normal braking by controlling a braking pressure generated separately from a master cylinder pressure.

[0002]

2. Description of the Related Art As a brake control device of this type, there is a conventional brake control device described in, for example, Japanese Patent Application Laid-Open No. 6-191393. In this conventional example, a hydraulic pressure control device is a proportional electromagnetic hydraulic pressure control device that controls the hydraulic pressure of a hydraulic pressure source to a height proportional to a current supplied to a coil, and detects an operation amount of a brake operation member. Operation amount detection means for performing
The control means sets the target wheel cylinder pressure based on the detection result of the operation amount detection means, and controls the supply current to the coil of the proportional electromagnetic hydraulic pressure control device so that the hydraulic pressure of the hydraulic pressure source is adjusted to the target wheel cylinder pressure. The wheel cylinder is provided with a hydraulic pressure of a value corresponding to the operation amount of the brake operation member, for example, a hydraulic pressure proportional to the operation amount, or a vehicle body deceleration proportional to the operation force. Pressure is supplied to suppress rotation of the wheels. If an abnormality occurs in the electrically controlled hydraulic brake and the hydraulic pressure from the hydraulic pressure source cannot be supplied to the wheel cylinder, switch to the mechanical brake that supplies the hydraulic pressure from the master cylinder directly to the wheel cylinder. I have to.

[0003]

However, in the above-mentioned conventional brake control device, current is supplied to the coil of the proportional electromagnetic hydraulic pressure control device because the viscosity of the liquid in the hydraulic pressure source changes according to the liquid temperature. The time from when the pressure is reached until the wheel cylinder pressure reaches the target wheel cylinder pressure changes depending on the liquid temperature of the hydraulic pressure source, and especially when the liquid temperature of the hydraulic pressure source is low, the proportional electromagnetic hydraulic pressure control device There is an unsolved problem that the time from when the current is supplied to the coil to when the wheel cylinder pressure reaches the target wheel cylinder pressure is delayed.

Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and does not increase the cost due to the provision of a temperature sensor for detecting the temperature of the working fluid. It is an object of the present invention to provide a brake control device capable of suppressing a time delay until the braking pressure of the braking means reaches a braking pressure target value and improving response characteristics regardless of the working fluid temperature.

[0005]

According to a first aspect of the present invention, there is provided a brake control device comprising: a master cylinder for outputting a working fluid having a braking pressure corresponding to an operation amount of a brake operating member; Braking pressure generating means for outputting a working fluid of an arbitrary braking pressure based on the value, and a braking pressure for selecting the working fluid output from the master cylinder and the braking pressure generating means and supplying the selected working fluid to the braking means disposed on the wheels. Selecting means, brake operation amount detection means for detecting an operation amount of the brake operation member, and setting a brake pressure target value for the braking means according to the brake operation amount detected by the brake operation amount detection means; A brake control unit that determines a pressure command value for the braking pressure generation unit based on the pressure target value and controls a braking pressure selection unit. A fluid temperature estimating means for estimating a working fluid temperature of the braking pressure generating means, wherein the braking control means is configured to perform the braking for a predetermined set time when an estimated value of the fluid temperature estimating means is equal to or less than a first threshold value. The pressure command value for the pressure generating means based on the detection value of the brake operation amount detecting means is increased and corrected by a predetermined correction amount.

According to the first aspect of the present invention, the working fluid temperature of the braking pressure generating means is estimated by the fluid temperature estimating means, and when the estimated working fluid temperature is equal to or less than a predetermined threshold value, a predetermined set time is set. In the meantime, the pressure command value based on the detection value of the brake operation amount detection means for the braking pressure generation means is increased and corrected by a predetermined correction amount, so that the pressure command value is increased when the viscosity of the working fluid is low, and The response delay of the braking pressure generating means is improved by accelerating the rise of the braking pressure.

According to a second aspect of the present invention, in the brake control device according to the first aspect, the braking control means performs an increase correction for the pressure command value when a magnitude of a change in a gradient of the braking pressure target value is predetermined. It is characterized in that it is performed when the value exceeds the value. In the invention according to the second aspect, by performing the increase correction on the pressure command value when the amount of change in the inclination of the braking pressure target becomes equal to or greater than a predetermined value, the response delay can be reduced without giving the driver an uncomfortable feeling. Improve.

Further, in the brake control device according to a third aspect, in the invention according to the first or second aspect, the brake control unit determines at least one of the set time and the predetermined correction amount by an estimation amount of the fluid temperature estimation unit. It is configured to be changed according to.

In the invention according to the third aspect, at least one of the set time and the correction amount for increasing and correcting the pressure command value is changed according to the estimated fluid temperature of the fluid temperature estimating means, so that the response delay can be made more accurate. To suppress. Furthermore, the brake control device according to claim 4 is the one according to claim 1.
In any one of the inventions according to any one of the first to third aspects, the braking pressure generating means includes a fluid pressure generating source having a fluid pressure pump, a pressure control valve for controlling the fluid pressure of the fluid pressure generating source to a reduced pressure, A fluid pressure detecting means for detecting a fluid pressure; and a pump driving means for driving and controlling the fluid pressure pump based on the fluid pressure detected by the fluid pressure detecting means. The fluid temperature is estimated based on an increase amount of the fluid pressure detecting means when the fluid pressure pump is driven by the pump driving means for a predetermined time in a non-braking state where is not operated. And

In the invention according to claim 4, the fluid temperature estimating means drives the fluid pump by the pump driving means by decreasing the fluid pressure when the fluid temperature of the fluid pressure generating source is in the non-braking state. At this time, since the amount of pressure increase of the fluid pressure detecting means changes according to the viscosity of the working fluid, the fluid temperature is estimated based on this.

Further, according to a fifth aspect of the present invention, in the brake control apparatus according to any one of the first to third aspects, the braking pressure generating means includes a fluid pressure generating source having a fluid pressure pump, and a hydraulic pressure generating source. A pressure control valve for controlling the fluid pressure of the fluid pressure source, fluid pressure detecting means for detecting the fluid pressure of the fluid pressure generating source, and drive control of the fluid pressure pump based on the fluid pressure detected by the fluid pressure detecting means. And a fluid temperature estimating means, wherein the fluid temperature estimating means is configured to detect the fluid pressure detecting means when the fluid pressure pump is driven by the pump driving means in a non-braking state in which the braking means is not operated. It is characterized in that the fluid temperature is estimated from the increase time required for the detection value to increase by a preset increase amount.

According to the fifth aspect of the invention, when the output pressure of the braking pressure generating means is reduced and the hydraulic pump is driven in the non-braking state, the detected value of the fluid pressure detecting means increases by a predetermined amount. Since the increase time required for the operation varies depending on the viscosity of the working fluid, the increase time is measured, and the fluid temperature is estimated based on the increase time.

According to a sixth aspect of the present invention, there is provided a brake control device according to any one of the first to third aspects, wherein the braking pressure generating means includes a fluid pressure generating source having a fluid pressure pump driven by an electric motor. A pressure control valve for controlling the fluid pressure of the fluid pressure generating source, a fluid pressure detecting means for detecting the fluid pressure of the fluid pressure generating source, and the fluid based on the fluid pressure detected by the fluid pressure detecting means. Pump driving means for controlling the driving of the pressure pump, wherein the fluid temperature estimating means is provided when the hydraulic pump is driven by the pump driving means in a non-braking state in which the braking means is not operated. The fluid temperature is estimated from the amount of change in the detected value of the fluid pressure detecting means and the current value of the electric motor.

Also in the invention according to the sixth aspect, when the fluid pressure pump is driven in the non-braking state, the amount of change in the detected value of the fluid pressure detecting means and the current value of the electric motor driving the fluid pump are different. Since it changes according to the viscosity of the working fluid, the fluid temperature is estimated based on these.

Further, the brake control device according to a seventh aspect of the present invention is the brake control device according to any one of the first to third aspects, wherein the braking pressure generating means includes a fluid pressure generating source having a fluid pressure pump driven by an electric motor. A pressure control valve for controlling the fluid pressure of the fluid pressure generating source, a fluid pressure detecting means for detecting the fluid pressure of the fluid pressure generating source, and the fluid based on the fluid pressure detected by the fluid pressure detecting means. Pump driving means for controlling the driving of the pressure pump, wherein the fluid temperature estimating means is provided when the hydraulic pump is driven by the pump driving means in a non-braking state in which the braking means is not operated. The fluid temperature is estimated from the amount of change in the detected value of the fluid pressure detecting means and the number of revolutions of the electric motor.

Also in this invention, when the fluid pressure pump is driven in the non-braking state, the amount of change in the detection value of the fluid pressure detecting means and the rotation speed of the electric motor driving the fluid pump are different. Since it changes according to the viscosity of the working fluid, the fluid temperature is estimated based on these.

Further, in a brake control device according to an eighth aspect of the present invention, in the invention according to any one of the first to third aspects, the braking pressure generating means includes a hydraulic pressure generating source having a hydraulic pressure pump; A pressure control valve for controlling the fluid pressure of the fluid pressure source, fluid pressure detecting means for detecting the fluid pressure of the fluid pressure generating source, and drive control of the fluid pressure pump based on the fluid pressure detected by the fluid pressure detecting means. At least when the fluid pressure estimating means is in a non-braking state in which the braking means is not operated and when the fluid pressure pump is in a non-driving state. It is characterized in that the fluid temperature is estimated from the decrease amount of the pressure detecting means.

In the invention according to the eighth aspect, when the hydraulic pressure pump is in the non-driving state and the hydraulic pressure pump is in the non-driving state, an internal leak of the pressure control valve constituting the braking pressure generating means causes the hydraulic pressure generating source to be disconnected. Since the fluid pressure gradually decreases, and the amount of the decrease changes according to the viscosity of the working fluid,
The fluid temperature is estimated by obtaining the amount of decrease during a predetermined time based on the value detected by the fluid pressure detecting means.

According to a ninth aspect of the present invention, there is provided a brake control device according to any one of the first to third aspects, wherein the braking pressure generating means includes a hydraulic pressure generating source having a hydraulic pressure pump; A pressure control valve for controlling the fluid pressure of the fluid pressure source, fluid pressure detecting means for detecting the fluid pressure of the fluid pressure generating source, and drive control of the fluid pressure pump based on the fluid pressure detected by the fluid pressure detecting means. The fluid temperature estimating means is in a non-braking state in which the braking means is not operated, and when the fluid pressure pump is in a non-driving state, The fluid temperature is estimated from the time required for the detected value to decrease by a predetermined amount.

In the ninth aspect of the present invention, similarly to the eighth aspect, in the non-braking state and the non-driving state of the fluid pressure pump, the fluid pressure of the fluid pressure generating source due to the internal leak of the pressure control valve is increased. Since the flow rate decreases and the flow rate changes depending on the viscosity, the fluid temperature can be estimated from the time required until the fluid pressure decreases by a predetermined amount.

Further, a brake control device according to a tenth aspect of the present invention is the brake control device according to any one of the first to third aspects, further comprising a braking pressure detecting unit that detects a braking pressure of the braking unit, and the fluid temperature estimating unit. The brake pressure target value is braked when the vehicle is stopped and the braking means is not operated, or when the vehicle is stopped and the detection value of the brake operation amount detecting means is constant. The fluid temperature is estimated from the time required until the detected value of the braking pressure detecting means reaches a braking pressure target value after a predetermined amount is increased from a value based on the detected value of the manipulated variable detecting means. .

According to the present invention, when the vehicle is stopped and the braking means is not operated or when the vehicle is stopped and the detection value of the brake operation amount detecting means is constant, In a state where the starting of the vehicle is suppressed, the braking pressure target value is increased by a predetermined amount, the braking pressure of the braking means is detected by the braking pressure detecting means, and the time until the braking pressure detection value reaches the braking pressure target value. Since this changes depending on the viscosity of the working fluid, by measuring this time,
The working fluid temperature can be measured.

The brake control device according to an eleventh aspect of the present invention is the brake control device according to the first to the third aspects, further comprising a braking pressure detecting unit for detecting a braking pressure of the braking unit, wherein the fluid temperature estimating unit is configured to stop the vehicle. Time and when the braking means is not operated, or when the vehicle is stopped and the detection value of the brake operation amount detecting means is constant,
The brake pressure target value is increased by a predetermined amount from a value based on the detection value of the brake operation amount detection means, and then the fluid temperature is estimated from the detection value of the braking pressure detection means after a lapse of a predetermined time. I have.

Also in the invention according to the eleventh aspect, when the vehicle is stopped and the braking means is not operated or when the vehicle is stopped and the detection value of the brake operation amount detecting means is constant, In a state where the start of the vehicle is suppressed, the braking pressure target value is increased by a predetermined amount, and the braking pressure of the braking means is detected by the braking pressure detecting means. Since the amount changes depending on the viscosity of the working fluid, the working fluid temperature can be measured by measuring the amount of change in the braking pressure.

[0025]

According to the first aspect of the present invention, when the fluid temperature estimated by the fluid temperature estimating means becomes equal to or less than the first threshold value, the pressure command value to the braking pressure generating means for a predetermined set time. Is corrected by a predetermined increase amount from the pressure command value based on the detection value of the brake operation amount detection means, regardless of the working fluid temperature of the braking pressure generating means, especially when the working fluid temperature is low. The time delay from when the pressure command value is output to the generating means until the braking pressure of the braking means reaches the target value can be improved, and the fluid temperature is estimated by the fluid temperature estimating means. The effect that there is no need to provide a detecting means is obtained.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the start timing for increasing the pressure command value of the braking pressure generating means is corrected by the slope of the braking pressure target value. Is set when the magnitude of the change becomes equal to or greater than a predetermined value, an effect is obtained that the initial time delay when the brake operation member is further depressed and depressed is improved.

According to the third aspect of the present invention, in addition to the effects of the first and second aspects of the present invention, any one of the predetermined set time and the predetermined correction amount is set according to the estimated temperature by the fluid temperature estimating means. Therefore, it is possible to achieve an effect that accurate control according to the estimated temperature of the fluid temperature estimating means can be realized.

According to the fourth and fifth aspects of the present invention, in addition to the effects of the first to third aspects, in addition to the effect of the invention according to the first to third aspects, when the brake operating member is not operated and the hydraulic fluid is driven by the pump driving means. Since the increase amount per unit time or the elapsed time per unit increase amount of the fluid pressure detecting means when the pressure pump is driven is measured, the effect that the working fluid temperature can be accurately estimated can be obtained.

Further, according to the inventions according to claims 6 and 7, in addition to the effects of the inventions according to claims 1 to 3, in addition to the effect of the invention according to claims 1 to 3, the fluid is supplied by the pump driving means in the non-braking state where the brake operating member is not operated. Since the detection amount of the fluid pressure detecting means and the motor current value or the number of revolutions when the pressure pump is driven are detected, the effect that the working fluid temperature of the fluid pressure generating source can be accurately estimated in a shorter time is obtained.

According to the eighth and ninth aspects of the invention, in addition to the effects of the first to third aspects, in addition to the non-braking state where the brake operating member is not operated and the hydraulic pump is driven. In the non-driving state, the decrease amount per unit time detected by the fluid pressure detection means or the elapsed time per unit decrease amount is measured, so the drive frequency of the fluid pressure pump is reduced, and the sound vibration performance and durability are improved. The effect is obtained.

According to the tenth and eleventh aspects of the present invention, in addition to the effects of the first to third aspects, in addition to the non-braking state or the vehicle stop state when the vehicle is stopped and the brake operating member is not operated. At a time and when the detection amount of the brake operation amount detecting means is constant, the braking pressure target value is increased by a predetermined amount from a value based on the detection value of the brake operation amount detecting means, and then the braking pressure of the braking pressure detecting means is increased. Since the time until the detected value reaches the braking pressure target value or the amount of increase per unit time is measured, it is possible to estimate the working fluid temperature of each braking means.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention. In the drawing, reference numeral 1 denotes a drive wheel, for example, as a front wheel side and a driven wheel according to the depression amount of a brake pedal 2 as a brake operation member. 2 for the rear wheel side
The system has two pressurizing chambers that generate a working fluid of a front wheel side master pressure PMf and a working fluid of a rear wheel side master pressure PMr of the system,
The master cylinder outputs the front wheel side master pressure PMf and the rear wheel side master pressure PMr generated in these pressurizing chambers from the front wheel side output port p1 and the rear wheel side output port p2, respectively.

The working fluid of the front-wheel side master pressure PMf output from the master cylinder 1 is supplied to a 3-port 2-position electromagnetic switching valve 3F and a 3-port 2-position electromagnetic direction switching valves 4FL and 4FR as braking pressure selecting means. Via left and right front wheel 5F
It is supplied to wheel cylinders 6FL and 6FR as braking means for applying a braking force to L and 5FR.

Similarly, the working fluid of the rear wheel side master pressure PMr output from the master cylinder 1 is supplied to the electromagnetic directional control valve 3R at the 3-port 2-position, the proportioning valve 7 and the 3-port 2-position as the braking pressure selecting means. Electromagnetic directional switching valve 4
It is supplied to the wheel cylinders 6RL and 6RR that apply a braking force to the left and right rear wheels 5RL and 5RR via the RL and 4RR.

Here, the electromagnetic directional control valve 3F has one input port ps connected to the front wheel side port p1 of the master cylinder 1, and one of the two output ports po1 and po2 connected to the stroke simulator 8F. And the other port po2 is connected to the solenoid on-off valves 4FL and 4F.
R is connected to one of the two input ports ps2, the input port ps and the output port po1 are communicated at the normal position, the output port po2 is shut off, and the input port ps and the output port po2 are communicated at the offset position. , And the output port po1 is shut off. Similarly, in the electromagnetic directional control valve 3R, one input port ps is connected to the rear wheel side port p1 of the master cylinder 1, and one of the two output ports po1 and po2 is connected to the stroke simulator 8R. The other port po2 is connected to the solenoid on-off valve 4RL via the provisional valve 7
And 4RR are connected to one of the two input ports ps2, and the input port ps and the output port po1 at the normal position.
And the output port po2 is closed, the input port ps and the output port po2 are connected at the offset position, and the output port po1 is closed.

The stroke simulators 8F, 8
Each of R simulates the oil consumption when connected to the front wheel side master pressure PMf and the rear wheel side master pressure PMr by the electromagnetic switching valves 3F and 3R, and reduces the oil amount discharged from the master cylinder 1. It is configured to absorb and consume to secure a driver's brake pedal depression feeling.

The output ports po of the electromagnetic directional control valves 4FL, 4FR and 4RL, 4RR are connected to the wheel cylinders 5FL, 5FR and 5RL, 5RR, and one input side ps2 is connected to the electromagnetic directional control valve 3F. And 3
The other input port ps1 is connected to a braking pressure generating circuit 9 as a braking pressure generating means.

In each of the electromagnetic switching valves 3FL to 3RR, the input port ps1 and the output port po communicate with each other at a normal position in which a control signal _SD supplied from the control unit 30 to be described later supplied to the solenoid s1 is off. Then, the input port ps2 is shut off, the input port ps1 is shut off at the offset position where the control signal _SD supplied to the solenoid s1 is on, and the input port ps2 and the output port po are communicated.

The braking pressure generating circuit 9 is connected to a reservoir 10 connected to the master cylinder 1 and connected to a low pressure side pipe 11L.
The suction side is communicated with the reservoir 10 and the electric motor 12
The high-pressure side pipe 11H communicated with the discharge side of the hydraulic pump 13 that is rotationally driven by the hydraulic pump 13 and the accumulator 14 for accumulating pressure connected between the discharge side of the hydraulic pump 13 and the high-pressure side pipe 11H. The pressure generating source 15, the input side and the return side port are connected to the high pressure side pipe 11H and the low pressure side pipe 11L, respectively, and the output port is individually connected to the other input side port of the electromagnetic directional control valves 4FL, 4FR and 4RL, 4RR. And pressure control valves 16FL, 16FR and 16RL, 16RR having a configuration of an electromagnetic proportional pressure reducing valve connected to the pressure control valve.

Here, when the accumulated pressure of the accumulator 14 becomes equal to or lower than a first set pressure set in advance, the hydraulic pump 13 is driven by the electric motor 12 being driven to rotate by a control unit 30 which will be described later. 14 is higher than the first set pressure.
To the set pressure.

Each of the pressure control valves 16FL to 16RR is configured to communicate between each port by a spool driven by an electromagnetic solenoid, and as shown in FIG. 2, a current value inputted to the electromagnetic solenoid is used. It is configured to output an output pressure Pc having a value proportional to the control signals CS _{FL to} CS _RR .

The brake pedal 2 is provided with a brake switch 21 for detecting depression and a depression force sensor 22 for detecting depression force. The electromagnetic direction switching valves 4FL to 4RR and the wheel cylinder are provided. 6FL ~
The brake pressure sensors 23FL to 23RR constituting brake pressure detecting means for detecting a wheel cylinder pressure as a brake pressure are provided in a hydraulic pipe connecting the 6RR and the brake pressure, and the accumulated pressure is stored in the accumulator 14 of the brake pressure generating source 15. A pressure accumulation sensor 24 constituting a fluid pressure detecting means for detecting is provided,
Further, wheel speed sensors 25FL to 25RR for detecting rotation speeds of the wheels 5FL to 5RR are provided.

The electromagnetic directional control valves 3F, 3R and 4
FL ~ 4RR, electric motor 12, pressure control valve 16FL ~
16RR is controlled by a braking control device 30 as a braking control means. The braking control device 30 includes at least an arithmetic processing device 32a, a ROM 32b, a RAM 32c, an input interface 32d, and an output interface 3
2e and a bus connecting them.

Then, the input interface unit 32d outputs A
/ D converter and the like, and the input interface unit 32d includes a brake switch 2
1, pedal force sensor 22, braking pressure sensors 23FL to 23R
R, pressure accumulation sensor 24 and wheel speed sensors 25FL-25R
R are connected to each other, and a longitudinal acceleration sensor 26 and a lateral acceleration sensor 27 that detect acceleration in the front-rear direction and left-right direction of the vehicle body are connected respectively.

The output interface section 32e includes a predetermined drive circuit, a D / A converter, etc., and includes an electromagnetic directional control valve 3F, 3R, 4FL-4RR, an electric motor 12
And the pressure control valves 16FL to 16RR.
The ROM 32b stores a control map representing the relationship between the brake pedal depressing force and the target deceleration, and a program required for the arithmetic processing of the arithmetic processing unit 32a.

The braking control by the braking control device 30 is normally performed by controlling the output pressures of the pressure control valves 16FL to 16RR based on the detected treading force of the treading force sensor 22, and the electromagnetic direction switching valves 3F, 3R and 4FL-4RR
Is controlled to the normal position shown in FIG. 1, and the master cylinder 1 is connected to the stroke simulators 8F and 8R.
6FL based on the output pressure of ~ 16RR
-6RR, the electromagnetic directional control valves 3F, 3R and 4FL-4RR are all switched to the offset position, and the front-wheel master pressure PMf and the rear-wheel master pressure PMr of the master cylinder 1 are switched. Is supplied to the wheel cylinders 6FL, 6FR and 6RL, 6RR, and is mechanically controlled.

Next, a description will be given of a brake control processing procedure in which the operation of the first embodiment is executed by the brake control device 30 with reference to flowcharts of FIGS. That is, the brake control device 30 executes the brake control process shown in FIG. 6 as a timer interrupt process every predetermined time (for example, 5 msec).

In the brake control process, first, in step S1, it is determined whether or not the brake pedal 2 is depressed. This determination is made based on whether or not the switch signal of the brake switch 21 is ON. When the switch signal of the brake switch 21 is OFF, it is determined that the vehicle is in the non-braking state, and the timer interrupt process is terminated and a predetermined Return to the main program of
When the first switch signal is in the ON state, it is determined that the vehicle is in the braking state, and the process proceeds to step S2.

In step S2, the detected value of the pedaling force of the pedaling force sensor 22 and the detected value of the longitudinal acceleration of the longitudinal acceleration sensor 26 are read. Then, the process proceeds to step S3, where the vehicle speed is determined based on the detected value of the pedaling force and the detected longitudinal acceleration. The target deceleration is determined, and then the process proceeds to step S4, where the target braking pressure P to be supplied to each wheel cylinder based on the target deceleration is determined.
After determining B ^* , the process proceeds to step S5.

In step S5, the command value determination processing shown in FIG. 4 is executed to determine the pressure command values for the respective pressure control valves 16FL to 16RR. Then, the process proceeds to step S6, where the determined pressure command values are set. Each pressure control valve 16FL
After .about.16RR are individually output, the timer interrupt process is terminated and the process returns to the predetermined main program.

In the command value determination process, as shown in FIG. 4, first, in step S11, it is determined whether or not the count value C1 of the software counter formed in the RAM 32c is "0". , The step S
Then, the process proceeds to step S12, in which the estimated liquid temperature value To determined in the estimated liquid temperature process shown in FIG. 5 is read. Then, the operation proceeds to step S23, where the read estimated liquid temperature value To is set to the first threshold value set in advance. It is determined whether it is not more than X1. If To> X1, it is determined that the working fluid temperature of the braking pressure generation source 15 is relatively high, and the process proceeds to step S24, where each wheel corresponding to the target braking pressure is determined. Calculate the pressure command values P _{FL to} P _RR of
After updating and storing in a predetermined storage area of the AM 32c, the timer interrupt processing is terminated, and the processing returns to the predetermined main program.
If To ≦ X1, the process moves to step S25.

In step S25, the change in the slope of the target braking pressure, that is, the change amount PB ^* 'per unit time is set to a preset value X2 (for example, about 10 to 50 kgf / cm).
² / sec) or more, and PB ^* ′
If <X2, it is determined that the change in the target braking pressure is small, and the routine proceeds to step S24, where PB ^* '<X
When it is 2, it is determined that the change in the target braking pressure is large, and the process proceeds to step S26.

In this step S26, the correction value DP and the set value DC are set to predetermined values, and then the process proceeds to step S27, in which the pressure command values P _{FL to} P _RR stored in the predetermined storage area of the RAM 32c are set. The values obtained by adding the correction values DP are updated and stored in the predetermined storage area of the RAM 32c as new pressure command values P _{FL to} P _RR , and then the process proceeds to step S28.

In step S28, the count value C1 of the software counter is incremented by "1", and the process proceeds to step S29 to determine whether the count value C1 has become equal to the set value DC (a value corresponding to about 10 to 300 msec). It is determined whether or not C1 <DC, the timer interrupt process is terminated as it is, and the process returns to a predetermined main program. If C1 = DC, step S is performed.
The flow shifts to 30, where the count value C1 is cleared to "0", the timer interrupt process is terminated, and the process returns to the predetermined main program.

On the other hand, if the result of determination in step S21 is that the count value C1 is not "0", the flow jumps directly to step S27. Further, as shown in FIG. 5, the working fluid temperature estimating process first determines whether or not the brake pedal 2 is depressed in step S31.
The brake switch 2
When the first switch signal is in the off state, it is determined that the vehicle is in the non-braking state, and the process proceeds to step S32.

In this step S32, it is determined whether or not a temperature estimation flag F indicating whether or not the fluid temperature estimation has been started is set to "1" indicating that the estimation has been started, and this is set to "0". If it has been reset, it is determined that the fluid temperature estimation has not been started and step S3
Move to 3.

In step S33, the pressure accumulation sensor 24
The accumulator pressure PA detected in step (1) is read, and then the process proceeds to step S34, where the accumulator pressure PA is set to a preset set pressure X3 (for example, about 50 to 150 kgf / cm).
² )), and if PA ≧ X3, it is determined that the temperature cannot be estimated, the timer interrupt process is terminated, and the process returns to the predetermined main program, where PA <X3. Sometimes, it is determined that the temperature can be estimated, and the process proceeds to step S35.

In step S35, the electric motor 12
, A rotational drive signal is output, the hydraulic pump 13 is rotationally driven, and the process proceeds to step S36. The temperature estimation flag F is set to "1", and then the process proceeds to step S37. In this step S37, step S33
Accumulator pressure P detected by the pressure accumulation sensor 24 in the same manner as
A, and then proceeds to step S38 to determine whether or not the accumulator pressure PA has reached the set pressure X3 or more. If PA <X3, the timer interrupt processing is terminated and the predetermined main program is executed. Return, P
If A ≧ X3, the process shifts to step S39 and R
After incrementing the count value C2 of the software counter formed on the AM 32c by "1", the process proceeds to step S
Move to 40.

In this step S40, the count value C2
Is greater than or equal to a predetermined threshold value X5 (for example, a value corresponding to about 1 to 10 seconds), and C2 <X5
If it is, the timer interrupt process is terminated and the process returns to the predetermined main program. If C2 ≧ X5, the process proceeds to step S41 to calculate the working fluid temperature estimated value.

The calculation of the estimated value of the working fluid temperature is based on the accumulator pressure PA read in step S37 and the set pressure X
An accumulator pressure change amount ΔPA, which is a value obtained by subtracting 3, is calculated, and based on the accumulator pressure increase amount ΔPA,
This is performed by calculating the working fluid temperature estimated value To with reference to the working fluid temperature calculation map shown in FIG. 6 stored in the ROM 32b in advance.

Next, the operation proceeds to step S42, in which the supply of the motor current to the electric motor 12 is stopped to stop the operation of the hydraulic pump 13, and then the operation proceeds to step S43, where the temperature estimation flag F is set to "0". At the same time as resetting, the count value C2 of the counter is cleared to "0", the timer interrupt processing is terminated, and the processing returns to the predetermined main program.

On the other hand, if the result of the determination in step S31 is that the brake signal is in the ON state and the brake pedal 2 is being depressed, the braking state is determined.
The process proceeds to step S44 and the temperature estimation flag F is set to “1”.
It is determined whether or not this is "1". If this is "1", the process proceeds to step S42, and if it is "0", the timer interrupt process is terminated and the process returns to the predetermined main program.

Therefore, the vehicle now has the brake pedal 2
If the vehicle is running in a non-braking state in which the brake pressure is released, the spool pressure control valves 16FL-1
6RR, an internal leak occurs between the supply port and the return port, and in the non-braking state, the pressure control valve 1
The accumulator pressure PA of the accumulator 9 gradually decreases even when 6FL to 16RR are not in operation.

Therefore, at the timing when the working fluid temperature estimating process of FIG. 5 is executed, in the non-braking state and when the temperature estimation flag F is reset to “0”, the accumulator pressure PA is increased in step S33. When the pressure is equal to or higher than the set pressure X3, the process is terminated without performing the working fluid temperature estimation. However, when the accumulator pressure PA falls below the set pressure X3, the process proceeds to step S35,
The drive of the hydraulic pump 13 is started, whereby the accumulator pressure PA is started to rise.

Next, the process proceeds to step S36, in which the temperature estimation flag F is set to "1", and then the accumulator pressure PA is read again. Immediately after the hydraulic pump 13 is started to be driven, the accumulator pressure PA is actually increased. Since the temperature has not risen and is lower than the set pressure X3, the temperature estimation process is terminated as it is.

Thereafter, since the temperature estimation flag F is set to "1", the process directly proceeds from the step S32 to the step S37, and when the accumulator pressure PA becomes higher than the set temperature X3, the process proceeds to the step S39. Then, the count value C2 of the counter is incremented by "1".

The count value C2 is equal to the set value X5.
When the predetermined time before reaching the predetermined time has not elapsed, the increment of the count value C2 is repeated. When the predetermined time elapses after the count value C2 reaches the set value X5, step S
41, the pressure increase amount ΔPA is calculated by subtracting the set pressure X3 from the accumulator pressure PA at that time, and based on this, the working fluid temperature estimation is performed with reference to the working fluid temperature calculation map of FIG. The value To is calculated and updated and stored in a predetermined storage area of the RAM 32c.

Thereafter, after the operation of the hydraulic pump 13 is stopped, the temperature estimation flag is reset to "0", and the count value C2 is cleared to "0". When the brake pedal 2 is depressed and the temperature estimation flag F is set to "1" to enter the braking state, step S44 is executed.
Then, the process shifts to step S42 to stop the temperature estimation process.

In this way, in the running state in the non-braking state where the brake pedal 2 is released, the working fluid temperature estimated value To is calculated every time the accumulator pressure PA falls below the set pressure X3. Since the working fluid temperature estimated value To is sequentially updated and stored in the RAM 32c in this manner, when the brake pedal 2 is depressed at the timing when the brake control process of FIG. The deceleration is calculated, and the target braking pressure PB ^* according to the target deceleration is determined. Based on the target braking pressure PB ^* , the pressure command value P _FL in the command value calculation process of FIG.
~ _PRR is calculated.

At this time, if the count value C1 has been cleared to "0" and the braking pressure increase process has not been performed, the process proceeds to step S22, where the fluid temperature estimation estimated in the above-described temperature estimation process is performed. The value To is read, and when this value is higher than the set temperature X1, the viscosity is small and the pressure control valve 1
It is determined that the response delay of the output pressure of 6FL to 16RR is small, and the process shifts to step S24 to calculate the pressure command values P _{FL to} P _RR corresponding to the target braking pressure PB ^*, and to calculate the calculated pressure command values P _{FL to} P _RR. To 16RR, the braking pressure of the wheel cylinders 6FL to 6RR is reduced by the pressure control valve 16F.
L-16RR, the braking force corresponding to the amount of depression of the brake pedal 2, that is, the amount of brake operation, is controlled by the wheels 5FL.
To 5RR.

However, when the estimated fluid temperature value To is equal to or lower than the set temperature X1, the process proceeds to step S25,
The amount of change P per unit time, which is the deviation between the previous value and the current value of the target braking pressure PB ^* calculated in step S4 in FIG.
If B ^* 'is less than the preset value X2, the process proceeds to step S24 to calculate the same pressure command values P _{FL to} P _RR as when the estimated fluid temperature value To is high.
When the change amount PB ^* 'is equal to or larger than the set value, step S27 is performed.
Then, a value obtained by adding the correction value DP to each of the pressure command values P _{FL to} P _RR is set as a new pressure command value P _{FL to} P _RR ,
After incrementing the count value C1, the pressure command values P _{FL to} P _RR corrected for increase are applied to the pressure control valves 16FL to 16R.
R, and this state is maintained until the count value C1 reaches the set value DC.

As a result, when the working fluid temperature estimated value To is low and the temperature is low, the pressure command values P _{FL to} P _RR are increased and corrected, so that the pressure control valve 16 F
Even in a state where the response delay of the output pressure of L to 16RR is large, the response is accelerated by the increase correction of the pressure command value, and the delay time can be improved.

In the first embodiment, the case where the correction value DP to be added to the pressure command values P _{FL to} P _RR and the set value DC representing the correction continuation time are set to predetermined values has been described. The correction amount calculation map shown in FIG. 7 is used to increase the rate of change of the correction value DP according to the decrease in the estimated working fluid temperature To, based on the estimated working fluid temperature To. The correction value DP according to the working fluid temperature estimated value To may be set in the same manner.
Based on the working fluid temperature estimated value To, the working fluid temperature estimated value T using a set value calculation map shown in FIG. 8 in which the rate of change of the set value DC increases as the working fluid temperature estimated value To decreases.
A setting value DC corresponding to the value o may be set.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, an estimated value of the working fluid temperature is calculated by measuring the elapsed time per unit change amount of the accumulator pressure. That is, in the second embodiment, as shown in FIG. 9, the working fluid temperature estimating process is performed in steps S40 and S41 in the process of FIG.
Are omitted, and steps S50 and S51 are provided instead. At step S50, the accumulator pressure PA is higher than the set pressure X3 by a predetermined pressure X4.
It is determined whether or not the above is satisfied. When PA <X4, the timer interrupt process is terminated as it is. When PA ≧ X4, the accumulator pressure PA changes by a predetermined amount of change ΔX (=
X4−X3), and it is determined that there has been a change in step S5.
Proceeds to 1, by multiplying the timer interrupt cycle count value C2 at that time, calculates the elapsed time t _T, in accordance with the elapsed time t _T which indicates the elapsed time t _T in Fig. 10 based on a longer Except for calculating the fluid temperature estimated value To with reference to the fluid temperature calculation map in which the fluid temperature estimated value To decreases, the same processing as the processing in FIG. 5 is performed, and the processing corresponding to FIG. Have the same step numbers, and detailed description thereof is omitted.

Here, as shown in FIG. 10, the working fluid temperature estimated value calculation map indicates that when the count value C2 is a small value, that is, when the elapsed time during which the accumulator pressure PA rises from the set pressure X3 to X4 is short. Then, the working fluid temperature estimated value To becomes high, and the line characteristic is set so that the working fluid temperature estimated value To becomes lower each time the count value C2 increases from this state.

According to the second embodiment, the accumulator pressure PA during non-braking when the brake pedal 2 is released.
Is lower than the set value X3, the hydraulic pump 1
3 to rotate and raise the accumulator pressure PA,
The elapsed time t _T until this reaches the set value X4 higher than the set value X3 is calculated, and based on this, the working fluid temperature estimated value calculation map of FIG. From the elapsed time can be accurately calculated.

Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, the working fluid temperature is estimated based on the accumulator pressure PA and the motor current when the pump is driven.
That is, in the third embodiment, as shown in FIG. 11, the working fluid temperature estimating process omits steps S39 to S41 in FIG. 5 in the first embodiment described above, and replaces them with steps S59 and S59. The same processing as in FIG. 5 is performed except that S60 is added,
Steps corresponding to those in FIG. 5 are denoted by the same step numbers, and detailed description thereof is omitted.

At step S59, the motor current detection value IM of the electric motor 12 for driving the hydraulic pump 13 is read, and then the routine proceeds to step S60, where the operation shown in FIG. 12 is performed based on the accumulator pressure PA and the motor current IM. The estimated working fluid temperature To is calculated with reference to the estimated fluid temperature calculation map. Here, the working fluid temperature estimated value calculation map of FIG. 12 is stored in the RAM 32c in advance, and using the accumulator pressure PA as a parameter, the working fluid temperature estimated value To decreases as the motor current detection value IM increases. Is set to That is, the working fluid temperature estimated value calculation map of FIG. 12 shows that when the working fluid temperature increases, the viscosity of the working fluid decreases in response to this, so that the load at the time of increasing the pressure by the hydraulic pump is reduced, which is necessary. The setting is made in accordance with a decrease in the motor current value.

According to the third embodiment, an accurate working fluid temperature estimated value To can be calculated based on the accumulator pressure PA and the detected motor current value IM, and the hydraulic pump 13 is driven at a certain time. Since the working fluid temperature is estimated using the detected motor current value IM and the accumulator pressure PA during the operation, there is an advantage that an accurate working fluid temperature estimated value To can be calculated in a shorter time.

In the third embodiment, the case where the estimated working fluid temperature To is calculated using the accumulator pressure PA and the detected motor current IM has been described. However, the present invention is not limited to this. as shown in FIG. 13, instead of the motor current detection value IM to read non-step S59, the motor speed N _M applies the read-free step S69, in place of step S60, the motor rotational speed N _M and the accumulator pressure By applying step S70 of estimating the working fluid temperature based on PA, an accurate estimated working fluid temperature value To can be estimated in a short time as in the third embodiment.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the fourth embodiment,
This is for estimating the working fluid temperature while the accumulator pressure PA is decreasing. That is, in the fourth embodiment, the working fluid temperature estimating process first determines in step S81 whether or not the brake pedal 2 is depressed, as shown in FIG. 14, and the brake pedal 2 is not depressed. In the non-braking state, the process proceeds to step S82, in which it is determined whether or not the temperature estimation flag FH indicating that the working fluid temperature is to be estimated in a state where the accumulator pressure is high is set to "1". If the temperature estimation flag FL indicating that the working fluid temperature estimation is to be performed in a state where the accumulator pressure is low is set to "1", it is determined whether or not the temperature estimation flag FL is set to "1".
If this is "0", the flow shifts to step S84.

In step S84, the accumulator pressure PA is read, and then the process proceeds to step S85 to determine whether the accumulator pressure PA is less than the preset pressure X3, and PA ≧ X3. Sometimes
In step S86, the motor current to the electric motor 12 is cut off to stop the hydraulic pump 13, and then the process proceeds to step S87, in which the temperature estimation flag FH is set, and the process proceeds to step 88.

In step S88, the accumulator pressure PA is read again, and then the process proceeds to step S89 to determine whether or not the accumulator pressure PA has become less than the set pressure X3.
The process proceeds to 90, where the count value C3 of the software counter formed in the RAM 32c is incremented by “1”, and then proceeds to step S91.

In step S91, the count value C3
Is a preset value X6 (for example, about 1 to 10 seconds)
It is determined whether or not C3 <
If X6, the timer interrupt process is terminated, and if C3 ≧ X6, the process proceeds to step S92.

In this step S92, the current accumulator pressure PA is subtracted from the set pressure X3 to calculate an accumulator pressure reduction amount ΔPA. Then, the flow shifts to step S93, and based on the calculated accumulator pressure reduction amount ΔPA. The fluid temperature estimated value To is calculated with reference to the fifteen fluid temperature estimated value calculation maps.

Here, as shown in FIG. 15, when the accumulator pressure decrease amount ΔPA is small, the working fluid temperature estimated value To is set to be low, and the accumulator pressure decrease amount ΔPA is changed from this state. As the working fluid temperature increases, the estimated working fluid temperature value To rapidly increases in the initial stage, and is thereafter set so that the amount of increase gradually decreases.

Then, the process shifts to step S94 to reset the temperature estimation flags FH and FL to "0",
After the count value C3 is cleared to "0", the timer interrupt processing ends. On the other hand, if the result of the determination in step S85 is PA ≧ X3, the flow shifts to step S95, sets the temperature estimation flag FL to “1”, and then shifts to step S96, where the accumulator pressure PA is read. Next, the routine proceeds to step S97, where it is determined whether or not the accumulator pressure PA is equal to or higher than the set pressure X3.
If X3, the process proceeds to step S98, in which the motor current to the electric motor 12 is interrupted to stop the hydraulic pump 13, and then to step S90, where PA <X
If it is 3, the process proceeds to step S99 to determine whether or not the count value C3 is "0". If it is not "0", the process proceeds to step S90. If it is "0", the timer interrupt process is terminated. I do.

Further, when the result of the determination in step S81 is that the brake pedal 2 is being depressed, the flow jumps directly to step S94, and the flow proceeds to step S82.
If the result of the determination is FH = "1", the process directly jumps to step S88, and if the result of the determination in step S83 is FL = "1", the process directly jumps to step S96.

According to the second embodiment, in the braking state where the brake pedal 2 is depressed, every time the processing of FIG.
94, the temperature estimation flags FH and FH
L has been reset to "0" and the count value C3 has been cleared to "0".

When the brake pedal 2 is released from the braking state to shift to the non-braking state, when the accumulator pressure PA is higher than the set pressure X3, as shown in FIG.
At the timing when the process of No. 4 is executed, the temperature estimation flag F
Since H and FL have been reset to "0", the process proceeds to step S86 through steps S81 to S85, whereby the hydraulic pump 13 is stopped, and the increase in the accumulator pressure PA is stopped, and then in step S87. The temperature estimation flag FH is set to "1", and the process directly jumps from step S82 to step S88 from the next time.

Therefore, as described above, the pressure control valve 16
The accumulator pressure PA gradually decreases due to the internal leak at FL to 16RR, and when the accumulator pressure PA is equal to or higher than the set pressure X3, the process is terminated as it is.
The count value C3 is incremented by "1", and then the process proceeds to step S91. However, since the count value C3 is small, the timer interrupt process ends.

When the count value C3 reaches the set value X6 by repeating this, the process proceeds to step S92, in which the current accumulator pressure PA is subtracted from the set pressure X3, and the unit time (X6 is multiplied by the timer interrupt period). The amount of decrease ΔPA in accumulator pressure per time) is calculated.

Then, the flow shifts to step S93, where the estimated working fluid temperature value To is calculated based on the calculated accumulator pressure reduction amount ΔPA with reference to the working fluid temperature estimated value calculation map in FIG. , The temperature estimation flags FH and FL are reset to “0”, and the count value C3 is set to “0”.
To clear.

On the other hand, when the accumulator pressure PA at the start of the temperature estimation is lower than the set pressure X3, steps S81 to S81
After step S85, the process proceeds to step S86, in which the temperature estimation flag FL is set to "1". Then, the accumulator pressure PA is read again, and is lower than the set pressure X3.
Then, the flow shifts from step S7 to step S99, and since the count value C3 has been cleared to "0", the timer interrupt processing ends as it is.

For this reason, from the next time, the process directly proceeds from step S83 to step S96, and the timer interrupt process is terminated as it is until the accumulator pressure PA becomes equal to or higher than the set pressure X3.
8, the operation of the hydraulic pump 13 is stopped, the increase in the accumulator pressure PA is stopped, and the pressure control valve 16F
The state shifts to a reduced state due to an internal leak of L to 16RR, and falls below the set pressure X3.

Then, the count value C3 is incremented by "1", so that the next step S9
The process proceeds to step S90 via 7, S99, and the count value C3 is counted up. When the count value C3 reaches the set value X6, the process proceeds from step S91 to step S92.
And the accumulator pressure PA is set to the set pressure X
3, the accumulator pressure decrease amount ΔP
A is calculated, and the fluid temperature estimated value To is calculated with reference to the fluid temperature estimated value calculation map.
The data is updated and stored in the predetermined storage area 2c.

According to the fourth embodiment, the first
To the third embodiment, an accurate fluid temperature estimated value To
Can be calculated, the effect can be obtained, and it is not necessary to drive the hydraulic pump when estimating the fluid temperature. Therefore, the operation frequency of the hydraulic pump can be reduced, and the sound vibration and durability can be improved.

In the fourth embodiment, the case where the accumulator pressure decrease amount ΔPA per unit time is calculated and the working fluid temperature is estimated based on this is described. However, the present invention is not limited to this. Instead of FIG.
As shown in FIG. 14, step S91 in FIG. 14 is replaced with step S101 for determining whether or not the accumulator pressure PA is equal to or less than a set pressure X7 lower than the set pressure X3, and when the determination result is PA ≦ X7. Step S
The process proceeds to step 102, where the count value C3 at that time is read, and then, in step S103, the working fluid temperature estimated value To is calculated based on the count value C3 with reference to the working fluid temperature estimated value calculation map in FIG. Even if you do
The same effects as in the fourth embodiment can be obtained.

In the first to fourth embodiments, the case has been described in which the increase / decrease amount of the accumulator pressure PA is calculated using the set pressure X3 as a reference pressure. However, the present invention is not limited to this. Instead of the pressure X3, the accumulator pressure PA at the time of starting the temperature estimation may be stored and set as the reference pressure.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. The fifth embodiment is a state in which the vehicle is stopped and the braking means is not operated,
And when the vehicle is stopped and the value detected by the brake operation amount detecting means is constant, the working fluid temperature is estimated.

That is, in the fifth embodiment, as shown in FIG. 17, first, in step S111, it is determined whether or not the vehicle is stopped. This determination is made for each wheel 5FL-
The determination is made by determining whether or not the wheel speed detection values of the wheel speed sensors 23FL to 23RR provided in the 5RR are all "0". When the vehicle is stopped, step S112 is performed.
Then, it is determined whether or not the brake pedal 2 is depressed. If the brake is in a braking state in which the brake pedal is depressed, the flow shifts to step S113 to detect the treading force detected by the treading force sensor 22 and the aforementioned figure. The target braking pressure PB ^* calculated in the brake control process 3 is read, and then the process proceeds to step S114, where it is determined whether the detected pedal force matches the previous value and there is no change in pedal force, and there is no change in pedal force. Sometimes, the process proceeds to step S115.

In step S115, the target braking pressure P
B^*At a predetermined pressure P0 (for example, 5 to 30 kgf / cm^TwoAbout
) Is corrected to a value obtained by adding the pressure command value P
_FL~ P _RRIs output to the pressure control valves 16FL to 16RR?
Then, the process proceeds to step S116.

In this step S116, the brake pressure detection values PB _{FL to} PB _RR of the brake pressure sensors 23FL to 23RR for detecting the brake pressure of each of the wheel cylinders 6FL to 6RR are read, and then the process proceeds to step S117 to read. It is determined whether the brake pressure detection values PB _{FL to} PB _RR match the target brake pressure PB ^*, and when they do not match, that is, when the brake pressure detection values PB _{FL to} PB _RR are lower than the target brake pressure PB ^* , the step is performed. In S118, when the count C4 of the software counter formed in the RAM 32c is incremented by "1", the timer interrupt process is terminated, and when the brake pressure detection values PB _{FL to} PB _RR match the target brake pressure PB ^*. Then, control goes to a step S119.

In step S119, the count value C4 at that time is read, and then, the process proceeds to step S120, and based on the count value C4, the operation is performed with reference to the working fluid temperature estimated value calculation map shown in FIG. The estimated fluid temperature To is calculated. Next, the process shifts to step S121 to clear the count value C4 to "0", and then shifts to step S122 to return the target braking pressure PB ^* to its original value, and then ends the timer interrupt process.

On the other hand, if the result of the determination in step S111 is that the vehicle is not stopped, the process jumps directly to step S121. If the result of the determination in step S112 is that the brake pedal 2 is not depressed, the process directly proceeds to step S11.
5, and if the result of determination in step S114 is that the pedaling force is not constant, the process directly jumps to step S121.

According to the fifth embodiment, when the vehicle is stopped and the braking means is not operated, or when the vehicle is stopped and the depression force of the brake pedal is constant, the target The braking pressure PB ^* is increased by a relatively small predetermined pressure P0, and the pressure control valves 16FL to 16RR are increased.
Braking pressure sensors 23FL to 23R
R, and the elapsed time until the detected braking pressure detection values PB _{FL to} PB _RR reach the increased target braking pressure PB ^* is measured, and the working fluid temperature estimated value To is calculated based on this. In addition to the effect of being able to calculate an accurate estimated working fluid temperature To as in the first to fourth embodiments, the working fluid temperature of each of the wheel cylinders 6FL to 6RR can be estimated. Therefore, by using this to individually control each of the pressure control valves 16FL to 16RR, it is possible to more accurately suppress a response delay occurring in the pressure control valve.

In the fifth embodiment, when the target braking pressure PB ^* is increased by the predetermined pressure P0, the working fluid temperature is determined based on the elapsed time until the braking pressure detection value matches the target braking pressure. Although the case where the estimated value is calculated has been described, the present invention is not limited to this. As shown in FIG. 19, the step S117 in FIG.
Step 127 which determines whether or not the value is equal to or longer than 10 sec) is determined.
If it is, the flow shifts to step S118, where C4 ≧
If it is X8, the process proceeds to step S128, and the value obtained by subtracting the braking pressure target value PB ^* before the predetermined pressure increase from the braking pressure detection values PB _{FL to} PB _RR at that time is determined as the braking pressure increase amount Δ
Calculated as PB _FL ~ ΔPB _RR , then step S12
9 to calculate the estimated working fluid temperature value To based on the braking pressure increase amounts ΔPB _{FL to} ΔPB _RR with reference to the working fluid temperature estimated value calculation map corresponding to FIG. 6 described above. Is also good.

In each of the above embodiments, the case where the pedaling force sensor 22 for detecting the pedaling force is applied as the pedal operation amount detecting means has been described. However, the present invention is not limited to this. A stroke sensor or a master pressure sensor that detects a master cylinder pressure discharged from the master cylinder 1 may be applied.

In each of the above embodiments, the case where the master cylinder pressure supplied to the wheel cylinders 6FL to 6RR and the output pressure from the pressure control valves 16FL to 16RR are switched by the electromagnetic direction switching valves 4FL to 4RR. However, the present invention is not limited to this, and an electromagnetic opening / closing valve may be interposed separately on the master cylinder 1 side and the pressure control valves 16FL to 16RR side. Further, the pressure control valves 16FL to 16RR may be Alternatively, the solenoid valve may be directly connected to the wheel cylinders 4FL to 4RR, and the solenoid valve may be inserted only on the master cylinder 1 side.

Furthermore, in each of the above-described embodiments, the case where the master cylinder 1 has two pressurizing chambers has been described. However, the present invention is not limited to this. One pressurizing chamber is used for the front wheel side and the rear wheel side. A master cylinder that outputs the master cylinder pressure can be applied. In this case, one of the two stroke simulators 8F and 8R can be omitted.

In each of the above embodiments,
Although the case where the front wheels are the drive wheels has been described, the present invention is also applicable to the case where the rear wheels are the drive wheels.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a characteristic diagram illustrating an output pressure characteristic with respect to a pressure reduction command value of a pressure control valve according to the first embodiment.

FIG. 3 is a flowchart illustrating an example of a brake control process according to the first embodiment.

FIG. 4 is a flowchart illustrating an example of a command value determination process in FIG. 3;

FIG. 5 is a flowchart illustrating an example of a working fluid temperature estimation process according to the first embodiment.

FIG. 6 is a characteristic diagram showing a working fluid temperature estimated value calculation map showing a relationship between an accumulator pressure increase amount and a working fluid temperature estimated value.

FIG. 7 is a characteristic diagram showing a relationship between a correction value DP and a working fluid temperature estimated value.

FIG. 8 is a characteristic diagram showing a relationship between a set value DC and a working fluid temperature estimated value.

FIG. 9 is a flowchart illustrating an example of a working fluid temperature estimation process according to the second embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a working fluid temperature estimated value calculation map representing a relationship between a count value and a working fluid temperature estimated value applicable to the second embodiment.

FIG. 11 is a flowchart illustrating an example of a working fluid temperature estimation process according to a third embodiment of the present invention.

FIG. 12 is a characteristic line diagram showing a working fluid temperature estimated value calculation map representing a relationship between a motor current and a working fluid temperature using an accumulator pressure as a parameter applicable to the third embodiment.

FIG. 13 is a flowchart of a working fluid temperature estimation process showing a modification of the third embodiment.

FIG. 14 is a flowchart illustrating an example of a working fluid temperature estimation process according to a fourth embodiment of the present invention.

FIG. 15 is a characteristic diagram showing a working fluid temperature estimated value calculation map representing a relationship between an accumulator pressure decrease amount and a working fluid temperature estimated value applicable to the fourth embodiment.

FIG. 16 is a flowchart of a working fluid temperature estimation process showing a modification of the fourth embodiment.

FIG. 17 is a flowchart illustrating an example of a working fluid estimating process according to the fifth embodiment of the present invention.

FIG. 18 is a flowchart of a working fluid temperature estimating process showing a modification of the fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Master cylinder 2 Brake pedal 3F, 3R Electromagnetic direction switching valve 4FL-4FR Electromagnetic direction switching valve 5FL-5RR Wheel 6FL-6RR Wheel cylinder 8F, 8R Stroke simulator 9 Braking pressure generating circuit 12 Electric motor 13 Hydraulic pump 14 Accumulator 15 Braking pressure Source 16FL to 16RR Pressure control valve 21 Brake switch 22 Treading force sensor 23FL to 23RR Brake pressure sensor 24 Accumulation sensor 26 Front-back acceleration sensor 30 Brake control device

Continuation of the front page (72) Inventor Mihiro Doi 2-term Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. F term (reference) 3D046 BB28 CC02 DD03 EE01 FF09 HH02 HH16 HH26 HH36 JJ03 JJ25 KK11 KK12 LL02 LL14 LL37 LL41

Claims (11)

[Claims] A master cylinder for outputting a working fluid having a braking pressure corresponding to an operation amount of a brake operating member; a braking pressure generating means for outputting a working fluid having an arbitrary braking pressure based on a pressure command value; A brake pressure selecting means for selecting a working fluid output from the cylinder and the brake pressure generating means and supplying the selected working fluid to a braking means disposed on the wheel; a brake operation amount detecting means for detecting an operation amount of the brake operating member; A brake pressure target value for the braking means is set in accordance with the brake operation amount detected by the brake operation amount detection means, and a pressure command value for the braking pressure generation means is determined based on the brake pressure target value. A brake control unit for controlling the selection unit, wherein the brake control unit includes a fluid temperature estimating unit for estimating a working fluid temperature of the braking pressure generating unit. Means for increasing, by a predetermined correction amount, a pressure command value based on a detection value of the brake operation amount detection means for the braking pressure generation means for a predetermined set time when an estimated value of the fluid temperature estimation means is equal to or less than a predetermined threshold value. A brake control device characterized in that correction is made. 2. The brake control means according to claim 1, wherein the increase in the pressure command value is corrected when the magnitude of the change in the slope of the brake pressure target value is equal to or greater than a predetermined value. 2. The brake control device according to 1. 3. The braking control unit according to claim 1, wherein at least one of the set time and the predetermined correction amount is changed according to the estimated amount of the fluid temperature estimating unit. 3. The brake control device according to 2. 4. The brake pressure generating means includes a fluid pressure source having a fluid pressure pump, a pressure control valve for controlling the fluid pressure of the fluid pressure source, and detecting a fluid pressure of the fluid pressure source. And a pump driving means for driving and controlling the hydraulic pump based on the fluid pressure detected by the fluid pressure detecting means, wherein the fluid temperature estimating means is operated by the braking means. The fluid temperature is estimated based on an increase amount of the fluid pressure detecting means when the fluid pressure pump is driven by the pump driving means for a predetermined time in a non-braking state. The brake control device according to any one of claims 1 to 3. 5. The brake pressure generating means includes a fluid pressure source having a fluid pressure pump, a pressure control valve for controlling the fluid pressure of the fluid pressure source, and a fluid pressure of the fluid pressure source. And a pump driving means for driving and controlling the hydraulic pump based on the fluid pressure detected by the fluid pressure detecting means, wherein the fluid temperature estimating means is operated by the braking means. In a non-braking state, the fluid temperature is estimated from an increase time required for the detection value of the fluid pressure detection means to increase by a preset increase amount when the fluid pressure pump is driven by the pump drive means. The brake control device according to any one of claims 1 to 3, wherein: 6. The fluid pressure generating means having a fluid pressure pump having a fluid pressure pump driven by an electric motor, a pressure control valve for controlling the fluid pressure of the fluid pressure source, and a fluid pressure generating valve. A fluid pressure detecting means for detecting a fluid pressure of the source, and a pump driving means for driving and controlling the fluid pressure pump based on the fluid pressure detected by the fluid pressure detecting means, wherein the fluid temperature estimating means comprises: In a non-braking state in which the braking means is not operated, the fluid temperature is determined from the amount of change in the detection value of the fluid pressure detecting means when the hydraulic pressure pump is driven by the pump driving means and the current value of the electric motor. The brake control device according to any one of claims 1 to 3, wherein the brake control device is estimated. 7. The braking pressure generating means includes a fluid pressure generating source having a fluid pressure pump driven by an electric motor, a pressure control valve for controlling the fluid pressure of the fluid pressure generating source, and the fluid pressure generating means. A fluid pressure detecting means for detecting a fluid pressure of the source, and a pump driving means for driving and controlling the fluid pressure pump based on the fluid pressure detected by the fluid pressure detecting means, wherein the fluid temperature estimating means comprises: In a non-braking state in which the braking means is not operated, the fluid temperature is determined from the amount of change in the detection value of the fluid pressure detecting means when the fluid pressure pump is driven by the pump driving means and the number of revolutions of the electric motor. The brake control device according to any one of claims 1 to 3, wherein the brake control device is estimated. 8. The braking pressure generating means includes a fluid pressure source having a fluid pressure pump, a pressure control valve for controlling the fluid pressure of the fluid pressure source, and detecting a fluid pressure of the fluid pressure source. And a pump driving means for driving and controlling the hydraulic pump based on the fluid pressure detected by the fluid pressure detecting means, wherein the fluid temperature estimating means is operated by the braking means. When there is no non-braking state, and when the hydraulic pump is in a non-driving state,
The fluid temperature is estimated from the amount of decrease of the fluid pressure detecting means after a predetermined time has elapsed.
The brake control device according to any one of the above. 9. The brake pressure generating means includes a fluid pressure source having a fluid pressure pump, a pressure control valve for controlling the fluid pressure of the fluid pressure source, and a fluid pressure of the fluid pressure source. And a pump driving means for driving and controlling the hydraulic pump based on the fluid pressure detected by the fluid pressure detecting means, wherein the fluid temperature estimating means is operated by the braking means. When there is no non-braking state, and when the hydraulic pump is in a non-driving state,
4. The brake control device according to claim 1, wherein the fluid temperature is estimated from a time required for the detection value of the fluid pressure detection means to decrease by a predetermined amount. 10. A brake pressure detecting means for detecting a braking pressure of the braking means, wherein the fluid temperature estimating means is provided when the vehicle is stopped and the braking means is not operated, and when the vehicle is stopped and the brake is applied. In any state where the detection value of the operation amount detection means is constant, the brake pressure target value is increased by a predetermined amount from a value based on the detection value of the brake operation amount detection means, and then the detection of the brake pressure detection means is performed. The brake control device according to any one of claims 1 to 3, wherein the fluid temperature is estimated from a time required until the value reaches the brake pressure target value. 11. A brake pressure detecting means for detecting a braking pressure of the braking means, wherein the fluid temperature estimating means is provided when the vehicle is stopped and the braking means is not operated, and when the vehicle is stopped and the brake is applied. When the detected value of the operation amount detecting means is in a constant state, the braking pressure target value is increased by a predetermined amount from a value based on the detection value of the brake operation amount detecting means, and the braking after a lapse of a predetermined time has elapsed. The brake control device according to any one of claims 1 to 3, wherein the fluid temperature is estimated from a value detected by the pressure detecting means.