JPH11115740A - Brake fluid pressure control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect leakage of a separation valve in a brake fluid pressure control device which has the separation valve for separating a first system from a second system of a fluid pressure circuit. SOLUTION: This type of device has a first system communicated with a master cylinder 14 and a second system communicated with a regulator 15. The first system is separated from the second system by means of a separation valve (SS)58. The first system is provided with master cut valves (SMC-1 )88 and (SMC-2 )90. A closed circuit including a fluid pressure sensor 62 is formed by closing the valves (SS)58, (SMC-1 )88 and (SMC-2 )90. After forming the closed circuit, pressure of fluid to be supplied from the regulator 15 to the valve (SS)58 is varied. Occurrence of leakage is determined when the fluid pressure in the closed circuit is varied together with variation of fluid pressure supplied to the valve (SS)58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake fluid pressure control device, and more particularly to a brake fluid pressure control device suitable as a device for controlling a brake fluid pressure in a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a device for controlling a brake fluid pressure in a vehicle, a device in which a hydraulic circuit is separated into a first system and a second system is known. In the above-mentioned conventional apparatus, two wheel cylinders of four wheels communicate with the first system. In the second system,
The remaining two wheel cylinders are in communication.

As described above, when the hydraulic circuit is divided into two systems, when one hydraulic circuit fails, the braking force is reliably generated by using the other hydraulic circuit. be able to. For this reason, according to the above-mentioned conventional apparatus, it is possible to realize excellent fail-safe performance against a failure of the hydraulic circuit.

[0004]

In a vehicle, there is a case where it is desired to generate a wheel cylinder pressure P _{W / C} different from the master cylinder pressure in the wheel cylinder of each wheel. The function of separating the hydraulic circuit into two systems and the function of meeting the above requirements can be realized by, for example, an apparatus described in Japanese Patent Application No. 9-96138 by the present applicant.

[0005] The above-described apparatus includes a first system to which wheel cylinders of two wheels among four wheels belong, and a second system to which wheel cylinders of the other two wheels belong. Both the first system and the second system are in communication with a hydro booster that generates a hydraulic pressure (hereinafter, referred to as a master cylinder pressure) in accordance with the brake depression force. The first system has a master cut valve between the hydro booster and the wheel cylinder. On the other hand, the second system includes a hydraulic pressure control valve between the hydro booster and the wheel cylinder. Further, the first system and the second system are communicated via a separation valve. The separation valve is disposed between a downstream portion of the first system master cut valve and a downstream portion of the second system hydraulic pressure control valve.

According to the above-described apparatus, if the master cut valve is opened and the separation valve is closed, the first
The two wheel cylinders belonging to the second system and the two wheel cylinders belonging to the second system can be connected to the hydro booster via different hydraulic systems. Therefore, according to the above-described device, by forming such a situation, a function of separating the hydraulic circuit into two systems can be realized.

On the other hand, according to the above-mentioned apparatus, the wheel cylinders of all the wheels are separated from the hydro booster by closing the master cut valve and opening the separation valve, and the hydraulic pressure control valve Can be communicated with.
Therefore, according to the above device, by forming such a situation, it is possible to realize a function of generating a wheel cylinder pressure different from the master cylinder pressure in the wheel cylinder of each wheel.

However, in a device for connecting the first system and the second system via the separation valve, if a failure occurs in the separation valve, the first system and the second system are completely connected. Separation, that is, the hydraulic circuit cannot be completely separated into two systems. Therefore, in such a device, it is desirable to be able to detect a leakage failure of the separation valve.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a brake fluid pressure control device capable of accurately detecting a leakage failure of a separation valve for separating a hydraulic circuit into two systems. With the goal.

[0010]

The above object is achieved by the present invention.
, A separation valve is provided between the first system communicating with the hydraulic pressure source and the second system communicating with the hydraulic pressure source, and at least the first system and the second system are connected to each other. One of the brake fluid pressure control devices includes a hydraulic pressure cut valve between the hydraulic pressure source and the separation valve, wherein the separation valve and the hydraulic pressure cut valve are both closed, and a closed circuit is provided between the two. A closed-circuit forming means for forming a closed-circuit, a hydraulic-pressure control means for changing a hydraulic pressure supplied from the hydraulic-pressure source side to the separation valve under the condition that the closed-circuit is formed, and the hydraulic-pressure control means This is achieved by a brake fluid pressure control device including: a leak failure detecting unit that detects leakage of the separation valve based on a fluid pressure change occurring in the closed circuit when the fluid pressure is changed.

In the present invention, when the hydraulic pressure cut valve is opened and the separation valve is closed, the first system and the second system are independently connected to the hydraulic pressure source. Can be realized. In the present invention, when the separation valve and the hydraulic pressure cut valve are closed, a closed circuit cut off from the hydraulic pressure source can be formed therebetween.

If no failure has occurred in the separation valve,
Even if the hydraulic pressure supplied from the hydraulic pressure source to the separation valve changes, the hydraulic pressure does not change inside the closed circuit. On the other hand, if a failure occurs in the separation valve, a change in the hydraulic pressure supplied from the hydraulic pressure source to the separation valve causes a change in the hydraulic pressure inside the closed circuit.
Therefore, according to the method of the present invention, the leakage failure of the separation valve can be accurately determined.

According to a second aspect of the present invention, in the brake fluid pressure control device according to the first aspect, the closed circuit forming means can store an initial hydraulic pressure higher than the atmospheric pressure in the closed circuit. A closed circuit condition judging unit that allows the formation of the closed circuit below, and the hydraulic pressure control unit compares a hydraulic pressure supplied to the separation valve after the closed circuit is formed with the initial hydraulic pressure. And a detection processing prohibiting means for prohibiting execution of processing necessary for detecting leakage of the separation valve when the initial hydraulic pressure exceeds a predetermined value. The brake fluid pressure control device is effective in preventing the generation of loud noise due to the detection of the leakage of the separation valve.

In the present invention, the leakage of the separation valve is detected by detecting the hydraulic pressure supplied from the hydraulic pressure source to the separation valve while the initial hydraulic pressure higher than the atmospheric pressure is stored in the closed circuit. This is performed by setting the hydraulic pressure lower than the hydraulic pressure. If a failure has occurred in the separation valve, the hydraulic pressure in the closed circuit is reduced as compared to the initial hydraulic pressure after the above processing is performed. On the other hand, if no failure has occurred in the separation valve, after the above processing is performed, no change in the hydraulic pressure occurs in the closed circuit. Therefore,
According to the above method, the leakage failure of the separation valve can be accurately determined.

In the present invention, in order to reduce the hydraulic pressure supplied from the hydraulic pressure source to the separation valve from the initial hydraulic pressure, it is necessary to discharge the brake fluid from between the hydraulic pressure source and the separation valve. At this time, if the initial hydraulic pressure is unduly high, a loud noise is generated along with the outflow of the brake fluid. Further, when a failure occurs in the separation valve, after the hydraulic pressure supplied to the separation valve is reduced from the initial hydraulic pressure, the hydraulic pressure in the closed circuit flows out through the separation valve. At this time, if the initial hydraulic pressure is unduly high, a loud noise is generated along with the outflow of the brake fluid.

Therefore, if the processing necessary for detecting a failure is executed even in a situation where the initial hydraulic pressure is unduly high, a loud noise is generated with the execution of the processing. In the present invention, when the initial hydraulic pressure exceeds a predetermined value, execution of processing necessary for detecting a leak failure is prohibited. For this reason, according to the present invention, it is possible to effectively prevent generation of loud noise due to detection of leakage failure.

Further, the above object is achieved by providing a separation valve between a first system communicating with a hydraulic pressure source and a second system communicating with a hydraulic pressure source. First
One of the system and the second system includes a hydraulic pressure cutoff valve between the hydraulic pressure source and the separation valve, and at least the other of the first system and the second system includes the hydraulic pressure control valve. A brake fluid pressure control device including a relief valve between a pressure source and the separation valve that allows a fluid flow from the hydraulic pressure source side to the separation valve side, wherein the relief valve and the hydraulic pressure In a state in which a hydraulic pressure higher than the atmospheric pressure is supplied to the cut valve, the separation valve is closed, and the hydraulic cut valve is opened to form an inspection state. This is achieved by a brake fluid pressure control device comprising: means for detecting leakage of the separation valve based on a differential pressure generated on both sides of the separation valve in a state where the inspection state is realized. Is done.

In the present invention, the inspection state is such that the hydraulic pressure cut valve is opened and the separation valve is closed when the hydraulic pressure source is generating a hydraulic pressure higher than the atmospheric pressure. This is realized by being in the valve state. When the inspection state is realized, the hydraulic pressure generated by the hydraulic pressure source is directly guided to the path from the hydraulic pressure cut valve to the separation valve. On the other hand, a hydraulic pressure obtained by subtracting the relief pressure of the relief valve from the hydraulic pressure generated by the hydraulic pressure source is led to the path from the relief valve to the separation valve.

Therefore, when no failure occurs in the separation valve, a differential pressure corresponding to the above-described relief pressure is generated on both sides of the separation valve. On the other hand, when a failure occurs in the separation valve, the differential pressure generated on both sides of the separation valve becomes smaller than that of the relief valve. Therefore, according to the method of the present invention, the leakage failure of the separation valve can be accurately determined.

[0020]

FIG. 1 shows a system configuration diagram of a braking force control device according to an embodiment of the present invention. The braking force control device according to the present embodiment includes an electronic control unit 10 (hereinafter referred to as an ECU 1).
0). Further, the braking force control device of the present embodiment includes a brake pedal 11. A brake switch 12 is provided near the brake pedal 11. The brake switch 12 outputs an ON signal when the brake pedal 11 is depressed. ECU10
Determines whether the brake pedal 11 is depressed based on the output signal of the brake switch 12.

The brake pedal 11 is a brake booster 1
3 is connected. The brake booster 13 is fixed to the master cylinder 14. The brake booster 13 amplifies the brake depression force applied to the brake pedal 11 and transmits the same to the master cylinder 14. The master cylinder 14 generates a master cylinder pressure PMC having a predetermined boosting ratio with respect to the brake depression force.

The master cylinder 14 has a regulator 1
5 is fixed. A reservoir tank 16 is provided above the master cylinder 14 and the regulator 15. Brake fluid is stored in the reservoir tank 16. The master cylinder 14 becomes conductive with the reservoir tank 16 when the depression of the brake pedal 11 is released.

The braking force control device has a pump 18. A reservoir tank 16 communicates with a suction hole of the pump 18. An accumulator 22 is connected to a discharge hole of the pump 18 via a check valve 20. The accumulator 22 accumulates the hydraulic pressure discharged from the pump 18 as an accumulator pressure P _ACC. The pump 18 discharges the brake fluid in the reservoir tank 16 to the accumulator 22 so that the accumulator pressure P _ACC falls within a predetermined range.

The accumulator 22 communicates with the regulator 15 described above. The regulator 15 uses the accumulator 22 as a high-pressure source and the reservoir tank 1
6 is used as a low pressure source to generate a hydraulic pressure equal to the master cylinder pressure PMC (hereinafter, referred to as a regulator pressure PREG). A fluid pressure passage 24 communicates with the regulator 15. The hydraulic pressure passage 24 has a brake hydraulic pressure sensor 26 (hereinafter, referred to as a hydraulic pressure sensor).
PREG sensor 26). PREG
The sensor 26 generates an output signal VREG according to the regulator pressure PREG. The ECU 10 outputs the output signal VREG.
The regulator pressure PREG is detected based on

In the hydraulic passage 24, a pressure increasing linear control valve 28 (hereinafter referred to as SLA 28) and a check valve 30
The hydraulic passage 31 communicates with the fluid passage 31 via the. SLA 28 is
The control valve opens when the hydraulic pressure in the hydraulic passage 24 is higher than a predetermined relief pressure Prel as compared with the hydraulic pressure in the hydraulic passage 31. The SLA 28 linearly changes the relief pressure Prel according to the drive signal supplied from the ECU 10. The check valve 30 is connected to the hydraulic passage 24 from the hydraulic passage 31 side.
It is a one-way valve that allows fluid flow to the side.

The hydraulic pressure passage 31 has a brake hydraulic pressure sensor 3
4 (hereinafter, referred to as a PRW sensor 34).
The PRW sensor 34 generates an output signal VRW according to the internal pressure PRW of the hydraulic passage 31. The ECU 10 detects the internal pressure PRW of the hydraulic passage 31 based on the output signal VRW. The hydraulic pressure passage 31 is provided with a pressure-reducing linear control valve 36 (hereinafter referred to as a
SLR 36) and a pressure-reducing reservoir 40 through a check valve 38. The SLR 36 is a control valve having a variable orifice therein. SLR3
6 changes the effective diameter of the orifice linearly according to the drive signal supplied from the ECU 10. Check valve 3
Reference numeral 8 denotes a one-way valve that allows a fluid to flow from the pressure reduction restriction reservoir 40 toward the hydraulic passage 31. The auxiliary reservoir 40 can store a predetermined amount of brake fluid therein.

A hydraulic passage 46 communicates with the hydraulic passage 31 via a holding valve 42 and a check valve 44. Holding valve 4
Reference numeral 2 denotes a two-position solenoid valve that keeps the valve open in a normal state and is closed when a drive signal is supplied from the ECU 10. On the other hand, the check valve 44 is a one-way valve that allows a fluid to flow from the hydraulic passage 46 to the hydraulic passage 31.

The hydraulic passage 46 communicates with the wheel cylinders 50 and 52 of the left and right rear wheels RL and RR via a P valve 48 and communicates with a reservoir passage 56 via a pressure reducing valve 54. The pressure reducing valve 54 is a two-position solenoid valve that maintains a closed state in a normal state and is opened when a drive signal is supplied from the ECU 10. Reservoir passage 56
Communicates with the reservoir tank 16 described above.

The hydraulic pressure passage 31 is connected to a separation valve 58 (hereinafter referred to as SS).
58) to the hydraulic passage 60. S
S58 is a two-position solenoid valve that keeps the valve closed in a normal state and is opened when a drive signal is supplied from the ECU 10. The internal pressure PFW of the hydraulic pressure passage 60 is Brake pressure sensor 62 that generates an output signal VF according to
(Hereinafter, referred to as a PFW sensor 62).
The ECU 10 detects the internal pressure PFW of the hydraulic passage 60 based on the output signal VF.

The hydraulic passage 60 communicates with the hydraulic passage 68 via a holding valve 64 and a check valve 66 and communicates with a hydraulic passage 74 via a holding valve 70 and a check valve 72. I have. Each of the holding valves 64 and 70 is a two-position solenoid valve that maintains an open state in a normal state and is closed when a drive signal is supplied from the ECU 10. On the other hand, the check valves 66 and 72 are one-way valves that allow only the flow of the fluid from the hydraulic passage 68 or the hydraulic passage 74 to the hydraulic passage 60.

The hydraulic passages 68 and 74 are respectively provided with wheel cylinders 76 and 78 of the left and right front wheels FL and FR.
And with the reservoir passage 56 via the pressure reducing valves 80 and 82. The pressure reducing valves 80 and 82 are two-position solenoid valves that maintain a closed state in a normal state and are opened when a drive signal is supplied from the ECU 10.

A hydraulic passage 84 communicates with the master cylinder 14. The hydraulic pressure passage 84 has a brake hydraulic pressure sensor 86
(Hereinafter, referred to as a PMC sensor 86). P
The MC sensor 86 generates an output signal VMC corresponding to the master cylinder pressure PMC. The ECU 10 outputs the output signal VM
The master cylinder pressure PMC is detected based on C. The hydraulic passage 84 also has a first master cut valve 88 (hereinafter, referred to as a first master cut valve 88).
Together with the liquid pressure passage 74 via the SMC _-1 referred to as 88) is communicated, the second master cut valve 90 (hereinafter, SMC _-2
90) is in communication with the hydraulic passage 68. S
The MC- ₁ 88 and the SMC- ₂ 90 are two-position solenoid valves that maintain a valve-open state in a normal state and are closed when a drive signal is supplied from the ECU 10.

The hydraulic pressure passage 84 is further connected to a brake stroke simulator 92. The brake stroke simulator 92 is composed of SMC _- 188 and SMC- _2.
When the valve 90 is closed, it is a mechanism for absorbing brake fluid flowing out of the master cylinder 14 and realizing an appropriate brake feeling. Next, the operation of the braking force control device according to the present embodiment will be described.

When it is determined that the brake pedal 11 has not been depressed by the driver (hereinafter, this state is referred to as "no braking required"), the ECU 10 sets all the control valves to the off state to implement the braking force control device. 1 (hereinafter referred to as a normal state). When the brake pedal 11 is depressed in a state where the normal state is realized, the PR
The EG sensor 26, the PFW sensor 62, and the PMC sensor 86 each provide a hydraulic pressure PRE corresponding to a brake operation amount.
Detect G, PFW and PMC.

When the detected values exceed a predetermined value, the ECU 10 determines that the brake pedal 11 has been depressed, that is, the driver has requested a braking force. When it is recognized that the brake fluid pressure control device functions normally, the ECU 10 starts the one-system fluid pressure control by detecting the occurrence of a braking request. One line pressure control is a SMC _-1 88 and SMC _-2 90 is turned on (closed), the on-state (open state) to SS58, and realized by performing cooperative control on SLA28 and SLR36 Is done.

When SMC _- 188 and SMC _- 290 are turned on (valve closed state) and SS58 is turned on (valve open state), the wheel cylinders of all wheels are
It is shut off from the master cylinder 14 and communicates with the hydraulic passage 31. Therefore, according to the one-system hydraulic pressure control, the wheel cylinder pressures of all the wheels can be controlled to be equal to the hydraulic pressure of the hydraulic pressure passage 31.

According to the SLA 28, a fluid pressure lower than the regulator pressure PREG by the relief pressure Prel can be supplied to the fluid pressure passage 31. Further, according to the SLR 36, the hydraulic pressure in the hydraulic passage 31 can be reduced by causing the brake fluid to flow from the hydraulic passage 31 to the auxiliary reservoir 40. The cooperative control of the SLA 28 and the SLR 36 is executed so that the hydraulic pressure in the hydraulic passage 31 matches the target hydraulic pressure. Therefore, according to the one-system hydraulic pressure control,
The fluid pressure in the fluid pressure passage 31, that is, the wheel cylinder pressure PWC of all the wheels can be controlled to an arbitrary fluid pressure equal to or less than the master cylinder pressure PMC.

According to the above-mentioned normal state, the hydraulic circuit of the brake hydraulic pressure control device controls the left and right front wheels FL,
It is separated into a first system communicating with the wheel cylinders 76, 78 of the FR and a second system communicating with the wheel cylinders 50, 52 of the left and right rear wheels RL, RR. At this time, the wheel cylinders 76 and 78 belonging to the first system are in conduction with the master cylinder 14, and the wheel cylinders 50 and 52 belonging to the second system are in conduction with the hydraulic passage 31.

If a failure is found in any of the pipes 46, 68, 74 leading to any of the wheel cylinders, the ECU 10 implements a brake fluid pressure control device even after the brake pedal 11 is depressed. The normal state shown in FIG. According to the normal state, it is possible to surely increase the wheel cylinder pressure PWC in a system in which no leakage occurs in the piping. Therefore, according to the brake fluid pressure control device of the present embodiment, it is possible to realize an excellent fail-safe property against a pipe leakage failure or the like.

By the way, in the brake fluid pressure control device of this embodiment, when a failure occurs in SS58,
Even if the ECU 10 requests the realization of the normal state, a situation occurs in which the first system and the second system cannot be completely separated. Therefore, in the brake fluid pressure control device of the present embodiment, it is desirable that the leakage failure of the separation valve SS can be reliably detected.

The braking force control apparatus according to the present embodiment responds to the above-mentioned request at a predetermined timing to detect a leakage failure of the SS 58 (hereinafter referred to as an SS leakage inspection).
Is performed. Hereinafter, FIGS. 2 to 5
With reference to FIG. FIG.
4 shows a flowchart of an example of a control routine executed by the ECU 10 in order to determine whether or not a start condition of the SS leakage inspection is satisfied. The routine shown in FIG. 2 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 2 is started, first, the process of step 100 is executed.

In step 100, it is determined whether bottoming has occurred in the auxiliary reservoir 40. In the brake fluid pressure control device, the brake fluid on the fluid pressure passage 31 side may flow into the auxiliary reservoir 40 via the SLR 36 during the execution of the one-system fluid pressure control. The brake fluid flowing into the auxiliary reservoir 40 is supplied to the brake pedal 1
After the depression of 1 is released, it is returned to the regulator 15 via the check valves 38 and 30. Therefore, no brake fluid remains inside the auxiliary reservoir 40 while the depression of the brake pedal 11 is released.

After the brake pedal 11 is depressed, the ECU 10 determines the amount of brake fluid that has flowed through the SLR 36 and flowed into the auxiliary reservoir 40 during the execution of the one-system hydraulic pressure control by the time when the drive signal was supplied to the SLR 36. And so on. In step 100, when the amount of brake fluid estimated to have flowed into the auxiliary reservoir 40 has reached the maximum capacity of the auxiliary reservoir 40, it is determined that bottoming has occurred in the auxiliary reservoir 40. On the other hand, if such a condition is not satisfied, the auxiliary reservoir 4
It is determined that bottoming has not occurred at 0.

In this embodiment, during the execution of the SS leakage inspection, a process of causing the brake fluid in the hydraulic passage 31 to flow out to the auxiliary reservoir 40 is executed. Auxiliary reservoir 4
If bottoming has occurred at 0, the above processing cannot be executed. Therefore, when it is recognized that bottoming has occurred in the auxiliary reservoir 40, execution of the SS leakage inspection should not be permitted. If such a determination is made in step 100, the process of step 102 is executed next.

In step 102, a start condition flag X is set to indicate that the start condition of the SS leakage inspection is not satisfied.
TESTSS is reset to “0”. This step 1
When the process of No. 02 is executed, the start of the SS leakage inspection is prohibited thereafter. When the process of step 102 is completed, the current routine is completed. If it is determined in step 100 in this routine that bottoming has not occurred in the auxiliary reservoir 40, then the process of step 104 is executed.

In step 104, it is determined whether a leak failure of the SLR 36 has been detected. During the execution of the SS leakage inspection, it is required to maintain a high hydraulic pressure in the hydraulic passage 31. If a leak failure has occurred in the SLR 36,
The high pressure hydraulic pressure cannot be maintained in the hydraulic pressure passage 31.
Therefore, if it is recognized that a failure has occurred in the SLR 36, execution of the SS leakage inspection should not be permitted. If such a determination is made in step 104, the process of step 102 is executed thereafter, and then the current routine ends.

In this routine, at step 104, SL
If it is determined that no failure has occurred in R36,
Next, the process of step 106 is performed. Step 10
At 6, it is determined whether or not the SS leakage inspection has not been completed. In the past SS leakage inspection, SS58
If a leak failure has already been detected, and SS5
If it is already detected that no leak failure has occurred in No. 8, it is determined in this step 106 that the SS leakage inspection has been completed. If the SS leakage inspection has already been completed,
There is no need to execute the SS leakage inspection again. Therefore, if it is determined in step 106 that the SS leakage inspection has been completed, the process in step 102 is performed thereafter, and the current routine is terminated.

If it is determined in step 106 in this routine that the SS leakage inspection is not yet completed, the process of step 108 is executed. In step 108, it is determined whether or not it is stored that the braking request has been turned off. The off memory of the braking request is deleted when the brake pedal 11 is depressed to such an extent that the master cylinder pressure PMC exceeds a predetermined value. Therefore, in step 108, after the master cylinder pressure PMC is sufficiently increased, it is determined that there is no braking request off memory until the brake pedal 11 is depressed.

In the present embodiment, the SS leakage inspection needs to be executed in a situation where the brake pedal 11 is continuously depressed after the master cylinder pressure PMC is sufficiently increased. Therefore, when it is determined in step 108 that the braking request is off, execution of the SS leakage inspection should not be permitted. Therefore, step 108
If such a determination is made, the process of step 102 is executed, and then the current routine is terminated.

If it is determined in the above step 108 that there is no braking request OFF memory, the process of step 110 is executed. In step 110, it is determined whether or not a braking request has occurred in the brake fluid pressure control device. When a braking request is generated in the brake fluid pressure control device, the wheel cylinder pressures higher than the atmospheric pressure are applied to the wheel cylinder cylinders 76 and 78 of the left and right front wheels FL and FR by executing one-system fluid pressure control. PW
It can be determined that C has been derived.

In this embodiment, the SS leakage inspection needs to be started in a situation where the wheel cylinder pressures PWC higher than the atmospheric pressure are generated in the wheel cylinders 76, 78 of the left and right front wheels FL, FR. is there. Therefore, step 1
If it is determined in step 10 that a braking request has not been issued,
The execution of the leakage check should not be permitted. Therefore, when such a determination is made in step 110, the process of step 102 is executed thereafter, and the current routine is terminated.

If it is determined in step 110 that there is no brake request OFF stored in this routine, then the process of step 112 is executed. In step 112, it is determined whether a system abnormality has occurred in the brake fluid pressure control device. The SS leakage inspection needs to be performed in a situation where no abnormality has occurred in the system. Therefore, if it is determined in step 112 that a system abnormality has occurred, execution of the SS leakage inspection should not be permitted. Therefore, when such a determination is made in step 110, the process of step 102 is performed thereafter, and then the current routine is terminated.

In this routine, if it is determined in step 112 that no system abnormality has occurred in the brake fluid pressure control device, then the process of step 114 is executed. In step 114, it is determined whether the vehicle is stopped. In the present embodiment, the response of the wheel cylinder pressure PWC may temporarily deteriorate during the execution of the SS leakage inspection. Therefore, the SS leakage inspection is desirably performed in a situation where deterioration of the responsiveness of the wheel cylinder pressure PWC does not substantially matter, that is, while the vehicle is stopped.

For this reason, if it is determined in step 114 that the vehicle is not stopped, the process of step 102 is executed to prohibit the execution of the SS leakage inspection. Is terminated. On the other hand, if it is determined in step 114 that the vehicle is stopped, the process of step 116 is executed next. In step 116, the lower hydraulic pressure min (PMC, PRE) of the master cylinder pressure PMC and the regulator pressure PREG is used.
G) satisfies α ≧ min (PMC, PREG)> β.

In this embodiment, the SS leakage test is performed under the condition that the master cylinder pressure PMC and the regulator pressure PREG are increased to a pressure higher than the atmospheric pressure, that is, the hydraulic pressure passage 31 It is started under the condition that a high fluid pressure is introduced. When the SS leakage test is started, a process of releasing the hydraulic pressure in the hydraulic pressure passage 31 to the auxiliary reservoir 40 via the SLR 36 is executed.

The hydraulic pressure in the hydraulic pressure passage 31 is controlled by the auxiliary reservoir 40.
When the vehicle is opened, noise is generated due to the flow of brake fluid. This noise is generated as the hydraulic pressure in the hydraulic passage 31 at the time when the SS leak test is started is higher, that is, the master cylinder pressure PMC and the regulator pressure PREG at the time when the SS leak test is started. The higher the pressure, the louder the sound.

The predetermined value α used in the condition of step 116 is a threshold value for suppressing the noise level to a level at which the occupant of the vehicle does not feel uncomfortable. Therefore, in step 116, α ≧ min (PMC, PRE
When it is determined that G) is not established, it can be determined that noise that gives discomfort to the occupant of the vehicle is generated by performing the SS leakage inspection. In this case, in order to prohibit the execution of the SS leakage inspection, the process of step 102 is thereafter executed, and then the current routine is terminated.

With the start of the SS leakage inspection, the hydraulic pressure passage 31
The process of releasing the internal hydraulic pressure to the auxiliary reservoir 40 is executed after all the holding valves 42, 64, 70 are closed. According to the above-described processing, after the hydraulic pressure in the hydraulic pressure passage 31 is released to the auxiliary reservoir 40, the hydraulic pressure guided to the hydraulic pressure passage 31 at the start of the SS leakage inspection is changed to the wheel cylinder 50 of each wheel. , 52, 76, 78.

In the present embodiment, the SS leakage inspection is executed in a situation where the vehicle is stopped. Step 11 above
The predetermined value β used under the condition of No. 6 is a wheel cylinder pressure P which is a minimum necessary for maintaining a stopped vehicle in a stopped state.
Master cylinder pressure PMC required to generate _{W / C}
And the regulator pressure PREG. Therefore, if it is determined in step 116 that min (PMC, PREG)> β does not hold, it can be determined that the vehicle may not be able to be properly maintained in the stopped state after the SS leakage inspection is started. . In this case, in order to prohibit the execution of the SS leakage inspection, the process of step 102 is thereafter executed, and then the current routine is terminated.

In step 116 of this routine, α ≧
If it is determined that min (PMC, PREG)> β holds, it is possible to execute the SS leakage inspection without generating an unduly loud noise and keeping the vehicle properly stopped. It can be determined that there is. in this case,
Next, the process of step 118 is executed. Step 11
At 8, the start condition flag XTESTSS is set to "1" to indicate that the SS leak test start condition has been satisfied. When the process of step 118 is performed, the current routine ends.

According to the above-described processing, there is no occurrence of a situation that hinders the execution of the SS leakage inspection (steps 100, 10).
4, 112), the SS leakage inspection is not completed (step 106), and the wheel cylinders 7 of the left and right front wheels FL, FR
While the sufficiently high wheel cylinder pressure PWC is guided to 6,78, one-system hydraulic pressure control is continuously performed (steps 108 and 110), and the vehicle stops before and after the SS leakage inspection starts. Maintain (steps 114, 116),
In addition, when no loud noise is generated with the execution of the SS leakage inspection (step 116), it can be determined that the SS leakage inspection start condition is satisfied.

FIGS. 3 and 4 show a flowchart of an example of a control routine executed by the ECU 10 to execute the SS leakage inspection. The routine shown in FIGS. 3 and 4 is a routine that is started each time the processing is completed. FIG.
When the routine shown in FIG. 4 is started, first, the process of step 120 is executed. In step 120, it is determined whether or not “1” is set in the start condition flag XTESTSS. As a result, if it is determined that XTESTSS = 1 does not hold, the current routine is terminated without any further processing. On the other hand, X
If it is determined that TESTSS = 1 is established, SS
Next, the process of step 122 is executed to start the leak inspection.

[0063] At step 122, the process of the SMC _-1 88 and SMC _-2 90 turned on (closed) is executed. In step 124, a process for turning off SS58 (valve closed state) is executed. According to the above processing, the wheel cylinders 76, 78 of the left and right front wheels FL, FR are provided between the SMC- ₁ 88 and SMC- ₂ 90 and the SS 58.
Is formed.

The processing in steps 122 and 124 is performed by the hydraulic cylinder 31 through the wheel cylinders 50, 5 of each wheel.
The operation is performed under the condition that the liquid pressure higher than the atmospheric pressure is supplied to 2, 76, 78. Therefore, when the above processing is executed, the hydraulic pressure passage 31 is started at the time when the SS leakage inspection is started.
Hydraulic pressure (hereinafter referred to as initial hydraulic pressure PSTA)
Is stored in the wheel cylinders 76, 78 of the front left and right wheels FL, FR, thereby forming the above closed circuit.

In step 126, a process is executed to turn the holding valves 42, 64, 72 of the front and rear wheels on (closed). When the above processing is executed, the initial hydraulic pressure PS is applied to the wheel cylinders 50, 52, 76, 78 of each wheel.
Wheel cylinder pressure PWC substantially equal to TA is stored. In step 128, a process for turning off the SLA 28 (state where the relief pressure Prel is maximum) is executed.

In step 130, a process for turning on the SLR 36 (state where the effective diameter is maximum) is executed. When the process of step 130 is completed, the process of step 132 shown in FIG. 4 is executed. According to the processing of steps 128 and 130, the flow of the brake fluid from the regulator 15 to the hydraulic pressure passage 31 can be cut off, and the hydraulic pressure passage 31 and the auxiliary reservoir 40 can be made conductive. Therefore, according to the above processing, the initial hydraulic pressure PSTA guided to the hydraulic pressure passage 31 can be released to the auxiliary reservoir 40.

If no leakage failure has occurred in SS58, the initial hydraulic pressure PSTA in the hydraulic passage 31 is
0, the initial hydraulic pressure PSTA remains inside the closed circuit.
Is saved. Therefore, in this case, step 13
After the process of 0 is performed, a large differential pressure is generated on both sides of SS58. On the other hand, if a leakage failure has occurred in SS58, after the initial hydraulic pressure PSTA in the hydraulic pressure passage 31 is released,
A situation occurs in which the hydraulic pressure in the closed circuit is released through SS58. In this case, after the process of step 130 is performed, the differential pressure generated on both sides of SS58 decreases with time.

For this reason, according to the brake fluid pressure control device of the present embodiment, the change in the differential pressure generated on both sides of the SS 58 after the processing of the step 130 is executed is monitored, so that the SS 58 is monitored. It is possible to accurately determine whether or not a leak failure has occurred. Step 13
In 2, it is determined whether or not the braking request has been turned off. When the braking request is turned off, it is necessary to reduce the wheel cylinder pressure PWC of each wheel to the atmospheric pressure. Therefore, when the braking request is turned off during the execution of the SS leakage inspection, it is appropriate to interrupt the SS leakage inspection and return the brake fluid pressure control device to the normal state. If it is determined in step 132 that the braking request has been turned off, then in step 13
4 is executed. On the other hand, if it is not determined that the braking request has been turned off, the process of step 136 is executed next.

In step 134, the execution of the SS leakage inspection is terminated, and a flag process for indicating that the SS leakage inspection is not completed is executed. Step 13
When the process of No. 4 ends, the current routine ends. S
If the flag process indicating that the leakage check has not been completed has been executed, then step 1 in the routine shown in FIG.
The condition of 06 is always satisfied. Therefore, in this case, the SS leakage inspection is performed again when another condition is satisfied.

In step 136, min (PMC, PR
It is determined whether or not a value obtained by subtracting the internal pressure PRW of the hydraulic passage 31 from EG) is larger than a predetermined value γ. min (PM
(C, PREG) -PRW is the magnitude of the differential pressure generated on both sides of the SLA 28. The predetermined value γ is SLA
This value is substantially equal to the maximum relief pressure of 28. Therefore,
If it is determined that min (PMC, PREG) -PRW> γ holds, it can be determined that a differential pressure exceeding the maximum relief pressure has been generated on both sides of the SLA 28.

When a differential pressure exceeding the maximum relief pressure is generated on both sides of the SLA 28, brake fluid flows from the regulator 15 side to the hydraulic pressure passage 31 side through the SLA 28. When the brake fluid flows into the hydraulic passage 31, S
Even if no leakage occurs in S58, the differential pressure between the internal pressure of the hydraulic passage 31 and the hydraulic pressure in the closed circuit may decrease. Therefore, under such circumstances, it is not possible to determine whether or not a leakage failure has occurred in SS58 based on the differential pressure generated on both sides of SS58.

For this reason, step 13 in this routine
If it is determined in step 6 that min (PMC, PREG) -PRW> γ is satisfied, the process of step 134 is executed, and then the current routine is terminated. On the other hand, when it is determined that the above condition is not satisfied, the process of step 138 is executed next. In step 138, it is determined whether the vehicle has started. When the vehicle has started, it is appropriate to immediately terminate the SS leakage inspection and release the wheel cylinder pressure PWC of each wheel to the atmospheric pressure. Therefore, if such a determination is made in step 138, the process of step 134 is executed, and then the current routine is terminated. On the other hand, if it is determined in step 138 that the vehicle has not started, the process of step 140 is executed next.

In step 140, it is determined whether an abnormality has occurred in the system of the brake fluid pressure control device.
As a result, when it is determined that an abnormality has occurred in the system, it is appropriate to immediately terminate the SS leakage inspection. Therefore, if such a determination is made in step 140, the process of step 134 is executed, and then the current routine is terminated. On the other hand, if it is determined in step 140 that no abnormality has occurred in the system, the process of step 142 is executed next.

In step 142, it is determined whether or not a leakage failure of SS58 has been detected. In step 142, specifically, when the fluid pressure PFW in the closed circuit decreases beyond a predetermined value after the SS leak test is started, or after the SS leak test is started, the SS 58 SS58 when the differential pressure generated on both sides of the
It is determined that a leak failure has occurred. Step 14
If it is determined in step 2 that a failure has occurred in SS58, the process of step 144 is executed next.

In step 144, it is stored that a leakage failure has occurred in SS58. After the process of step 144 is executed, the ECU 10 thereafter executes a process for notifying the driver of the vehicle of the occurrence of the failure. In this routine, if it is determined in step 142 that the leakage failure of SS58 has not been detected, then in step 14
6 is executed.

[0076] At step 146, after the execution of the SS leakage inspection is started, specifically, after the process of step 132 is executed first, whether or not a predetermined time T ₀ has elapsed is determined . The predetermined time T ₀ is a time necessary and sufficient for detecting the occurrence of the leakage failure based on the change in the hydraulic pressure PFW in the closed circuit when the leakage failure occurs in the SS 58.

Therefore, if it is determined in step 146 that the predetermined time T ₀ has elapsed, the program proceeds to step SS58.
It cannot be concluded that no leak failure has occurred.
In this case, the process of step 132 is executed again after step 146. On the other hand, step 14
6, if the predetermined time T ₀ is determined to have passed, it can be concluded that a fault leakage in SS58 has not occurred. In this case, the process of step 148 is executed next.

At step 148, it is stored that SS58 is normal. During this routine, the above step 14
When the processing in step 8 or the processing in step 144 is executed, the processing in step 150 is executed next. In step 150, the execution of the SS leakage inspection is terminated, and a flag process for indicating that the SS leakage inspection is completed is executed. When the process of step 150 ends, the current routine ends.

The flag indicating the completion of the SS leakage inspection is maintained in the set state until the ignition switch (IG switch) of the vehicle changes from the off state to the on state again, that is, until the vehicle is restarted. Is done. While the flag indicating the completion of the SS leakage inspection is maintained in the set state, the condition of step 106 in the routine shown in FIG. 2 is always not satisfied. Therefore, hereinafter, IG
While the switch is kept on, the SS leakage check is not performed again.

FIG. 5 is a time chart for explaining the operation before and after the SS leakage inspection is performed in the brake fluid pressure control device of this embodiment. The time chart shown in FIG. 5 is realized when no system abnormality has occurred in the brake hydraulic pressure control device and no bottoming has occurred in the auxiliary reservoir 40 during execution of the one-system hydraulic pressure control.

When a braking request is made continuously during the running of the vehicle (FIG. 5A), the vehicle speed SPD gradually decreases (FIG. 5).
(B)). According to the brake fluid pressure control device of the present embodiment,
Until the vehicle stops, one-system hydraulic pressure control is executed. During this time, SMC _- 188, SMC- ₂ 90, and S
S58 is controlled to the ON state (FIG. 5C, FIG.
(D) and FIG. 5 (E)) together with the SLA 28 and the SLR.
36 is subjected to cooperative control (FIG. 5E, FIG.
(F)).

According to the routine shown in FIGS. 3 and 4, when the vehicle stops while the braking request is continuously generated, the SS leakage inspection is started at that time. When the SS leakage inspection is started, SMC _- 188 and SMC _- 290 are used.
SS58 is controlled to be in the off state (valve closed state) while being maintained in the on state (valve closed state) (FIGS. 5C and 5C).
(D) and FIG. 5 (E)), the SLA 28 is closed, the SLR 36 is opened, and the holding valves 42 and 6 are closed.
4, 72 are controlled to the on state (valve closed state).

After the vehicle stops, the driver of the vehicle keeps the state where the brake pedal 11 is depressed, that is, the state where a braking request is generated, until the vehicle is normally started. The SS leakage inspection is performed for a time T ₀ that is sufficiently shorter than the time that the brake pedal 11 is kept depressed.
(For example, 500 msec). Therefore, according to the brake fluid pressure control device of the present embodiment, it is possible to quickly and accurately determine whether or not the SS 58 has a failure after the vehicle is brought to a stop by the brake operation. Can be.

In the above embodiment, the master cylinder 14 and the regulator 15 correspond to the "hydraulic pressure source" of the first embodiment, the SS 58 corresponds to the "separation valve" of the first embodiment, and the SMC _- 188. And SMC 90 as defined in claim 1
The "closed circuit forming means" according to claim 1 corresponds to the "hydraulic cut valve" described above, and the ECU 10 executes the processing in steps 122 and 124, whereby the "closed circuit forming means" according to claim 1 The “hydraulic pressure control means” according to claim 1 is realized by executing the processing of step 130, and the “leakage failure detection means” according to claim 1 is realized by executing the processing of step 142. I have.

In the above embodiment, the SLA2
8 corresponds to the "hydraulic pressure reducing means" according to the second aspect, and the ECU 10 executes the steps 108, 11
The "closed circuit condition determining means" according to claim 2 is executed by executing the processing of steps 0, 118 and 120, and the "detection processing inhibiting means" is executed by executing the processing of step 116. , Respectively.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 to 8 together with FIG. The driver of the vehicle usually starts the vehicle with the brake pedal 11 depressed. More specifically, the brake pedal 1
The operator operates the IG switch of the vehicle from the OFF state to the ON state while depressing step 1. The brake fluid pressure control device shown in FIG. 1 necessarily maintains the normal state while the IG switch is in the off state. Therefore, when the driver of the vehicle depresses the brake pedal 11 before turning on the IG switch, the master cylinder pressure PMC is guided to the wheel cylinders 76, 78 of the left and right front wheels FL, FR, while From the regulator pressure PREG to the SL
A liquid pressure obtained by reducing the maximum relief pressure of A28 is led.

In this case, under the condition that no leakage failure has occurred in SS58, a differential pressure substantially equal to the maximum relief pressure of SLA 28 is generated on both sides of SS58. On the other hand, SS58
If a leak failure occurs in the SLA 28, the differential pressure generated on both sides of the SS 58 becomes a value sufficiently smaller than the maximum relief pressure of the SLA 28. Therefore, according to the brake fluid pressure control device shown in FIG. 1, when the IG switch is operated from the off state to the on state, it is determined whether an appropriate differential pressure is generated on both sides of the SS 58, It is possible to accurately determine whether or not a leakage failure has occurred in SS58.

The brake fluid pressure control apparatus of this embodiment maintains the normal state until the brake pedal 11 is once released after the IG switch of the vehicle is operated from the off state to the on state. And the brake pedal 11
After the depression of the brake pedal is once released, the brake pedal 11
Is executed, the one-system hydraulic pressure control is executed. The brake fluid pressure control device according to the present embodiment is characterized in that after the IG switch is turned on, the leak failure of SS58 is detected by the above-described method while the normal state is maintained as described above. ing. Hereinafter, the above features will be described.

The brake fluid pressure control device of this embodiment can be realized by causing the ECU 10 to execute the routines shown in FIGS. 6 to 8 in the system configuration shown in FIG. FIG. 6 shows a flowchart of a control routine executed by the ECU 10 in the brake fluid pressure control device of the present embodiment to determine whether or not the execution condition of the SS leakage inspection is satisfied. The routine shown in FIG. 6 is a periodic interrupt routine that is started every predetermined time. FIG.
Is activated, the process of step 152 is first executed. In FIG. 6, the steps for executing the same processing as the steps shown in FIG.
The same reference numerals are given and the description is omitted.

In step 152, it is determined whether or not the pre-maintenance of the ECU 10 has been completed, that is, one second has elapsed after the completion of the processing required for the activation of the ECU 10. The ECU 10 is in a state where the system can be checked by the completion of the pre-maintenance. In this embodiment, when 1 second has elapsed after the completion of the pre-maintenance, it can be determined that all the various processes to be executed prior to the execution of the SS leakage inspection have been completed.

In other words, it can be determined that the state in which the SS leakage inspection can be started has not yet been realized until one second elapses after the completion of the pre-maintenance. Therefore, the execution of the SS leakage inspection should not be permitted until one second elapses after the completion of the pre-maintenance. Step 15 in this routine
If it is determined in step 2 that one second has elapsed after the completion of the pre-maintenance, the process of step 108 is executed next. On the other hand, if it is determined in step 152 that 1 sec has not elapsed after the completion of the pre-maintenance, the current routine is terminated without any further processing.

In steps 108 to 114, as in the case of the routine shown in FIG. 2, whether a braking request has been continuously generated (steps 108 and 110) or whether an abnormality has occurred in the system (step 112). ,and,
It is determined whether the vehicle is stopped (step 114). If any of these conditions are not met,
This routine ends without executing the processing of step 154 and subsequent steps. On the other hand, when all of these conditions are satisfied, the process of step 154 is executed next.

In step 154, δ ≧ min (PMC,
(PREG)> β is determined. The predetermined value δ is the master cylinder pressure PMC at the start of the SS leakage inspection.
And the maximum allowable hydraulic pressure for the regulator pressure PREG. By the way, in the first embodiment described above,
After the SS leakage inspection is started, a process of causing the brake fluid in the hydraulic pressure passage 31 to flow to the auxiliary reservoir 40 is executed. At this time, the brake fluid pressure control device generates noise due to the flow of brake fluid. Therefore, in the first embodiment, as described above, the master cylinder pressure PMC and the regulator pressure P
It is necessary to regulate the REG to a hydraulic pressure α that does not generate an unduly large noise.

On the other hand, in this embodiment, SS
During the execution of the leakage inspection, a process involving the circulation of a large amount of brake fluid is not executed. Therefore, in the present embodiment, it is not necessary to regulate the master cylinder pressure PMC and the regulator pressure PREG at the start of the SS leakage inspection from the viewpoint of suppressing the flow noise of the brake fluid.
Therefore, the predetermined value δ used in step 154 is used.
Is set to a value larger than the threshold value α used in the first embodiment (see step 116 in FIG. 2).

In step 154 of this routine, δ ≧
If it is determined that min (PMC, PREG)> β does not hold, it can be determined that the master cylinder pressure PMC and the regulator pressure PREG do not satisfy the SS leakage inspection start condition. In this case, the current routine is terminated without any further processing. On the other hand, in step 154, δ ≧ min (PMC, PRE
If it is determined that G)> β holds, it can be determined that the master cylinder pressure PMC and the regulator pressure PREG satisfy the condition for starting the SS leakage inspection. in this case,
Thereafter, in step 118, the start condition flag XTESTSS
Is set to "1", the current routine ends.

According to the above processing, after the IG switch is turned on, a state in which the SS leakage inspection can be executed is formed (step 152), and a braking request is continuously generated (step 152). (Steps 108 and 110), when no system abnormality is detected (Step 112), the vehicle is stopped (Step 114), and the master cylinder pressure PMC and the regulator pressure PREG are within appropriate ranges. It can be determined that the SS leakage inspection start condition is satisfied.

FIG. 7 shows the counting of the time required after the condition for starting the SS leakage inspection is established and before a situation where it is possible to determine the presence or absence of a leak failure based on the differential pressure generated on both sides of SS 58 is formed. 4 is a flowchart illustrating an example of a control routine executed by the ECU 10 to perform the control. The routine shown in FIG. 7 is a routine that is started each time the processing is completed. When the routine shown in FIG.
The processing of 56 is executed.

In step 156, it is determined whether or not the start condition of the SS leakage inspection is satisfied, specifically, whether or not the start condition flag XTESTSS is set to "1". As a result, if it is determined that XTESTSS = 1 does not hold, the current routine is terminated without any further processing. On the other hand, XTEST
If it is determined that SS = 1 holds, the process of step 158 is executed next.

In step 158, the regulator pressure PR
The EG, the hydraulic pressure PRW in the hydraulic pressure passage 31, and the differential pressure PREG-PRW between PREG and PRW are stored as initial values PREGSS, PRWSS, and POFSS, respectively. The initial values PREGSS, PRWSS, and POFSS respectively correspond to the regulator pressure PREG, the hydraulic pressure PRW, and the differential pressure PREG-PRW at the time when the SS leakage inspection start condition is satisfied.

At step 160, the counter SSCNT
Starts counting up. Counter SSCNT
Is a counter for counting the elapsed time after the SS leakage inspection start condition is satisfied. In step 162,
It is determined whether or not the braking request has been turned off, that is, whether or not the depression of the brake pedal 11 has been released. As described above, the brake fluid pressure control device of the present embodiment maintains the normal state until the depression of the brake pedal 11 is released after the IG switch is turned on.

While the brake fluid pressure control device is maintained in the normal state and the brake pedal 11 is depressed, a differential pressure substantially equal to the maximum relief pressure of the SLA 28 is introduced to both sides of the SS 58. On the other hand, when the depression of the brake pedal 11 is released in such a situation, SS5
The differential pressure that has occurred on both sides of 8 is reduced. In this embodiment, in order to detect an SS leakage failure, it is necessary to guide an appropriate differential pressure to both sides of SS58. Accordingly, when the depression of the brake pedal 11 is released, SS5
When the differential pressure generated on both sides of the pressure sensor 8 is reduced, the SS leakage failure cannot be detected. In this embodiment,
When it is determined in step 162 that the braking request has been turned off, it can be determined that a state in which the SS leakage failure cannot be detected has been formed. In this case, the process of step 163 is performed after step 162.

In step 163, a process for interrupting the SS leakage inspection is executed. Specifically, in step 163, the execution of the SS leakage inspection is terminated, and
A process for resetting the start condition flag XTESTSS to “0” is executed. When the process of step 163 ends, the current routine ends. In this embodiment,
By executing the routine shown in FIG. 6, the start condition flag XTESTSS is set to "1" only once after the IG switch is turned on and one second has elapsed after the completion of the main control. . Therefore, after the process of step 163 is executed, the start condition flag XETTSS is always maintained at “0” while the IG switch is kept on.

In this embodiment, in order to start the SS leakage inspection, the start condition flag X
It is necessary to determine that "1" is set in TESTSS. Therefore, after the process of step 163 is executed, the execution of the SS leakage inspection is prohibited while the IG switch is kept on. If it is determined in step 162 that the braking request has not been turned off in this routine, the process of step 164 is performed next.

In step 164, it is determined whether or not the amount of operation of the brake pedal 11 has decreased by a predetermined value ε or more from the previous processing cycle to the current processing cycle. In step 164, specifically, the regulator pressure PRE detected in the previous processing cycle is specified.
G (PREG (n-1)) and the larger one of the regulator pressures PREG detected in the current processing cycle, MAX (P
REG (n-1), PREG) is PREG ≦ MAX (P
It is determined whether REG (n-1), PREG)-[epsilon] is satisfied. As a result, PREG ≦ MAX (PREG (n−
1) If it is determined that (PREG) −ε holds,
It can be determined that the regulator pressure PREG has decreased by the predetermined value ε or more from the previous processing cycle to the current processing cycle.

When the brake fluid pressure control device is maintained in the normal state, for example, when the regulator pressure PREG becomes SL
When the pressure is reduced in a region lower than the maximum relief pressure of A28, the hydraulic pressure PRW of the hydraulic passage 31 does not change. On the other hand, the hydraulic pressure PFW on the left and right front wheels 76, 78 shows a change following the regulator pressure PREG at that time. Therefore,
Under such circumstances, the differential pressure generated on both sides of SS58 may decrease with time even if no leak failure has occurred in SS58.

In this embodiment, if the SS leakage inspection is continued in such a situation, a leakage failure of SS58 may be detected. Therefore, it is appropriate not to continue the SS leakage inspection under a situation where the operation amount of the brake pedal 11 is decreasing. For this reason, in this routine, if it is determined in step 164 that the operation amount of the brake pedal 11 has decreased, then the process of step 163 is executed, and then the current routine ends. On the other hand, in step 164, the brake pedal 1
If it is determined that the manipulated variable of No. 1 has not decreased, the process of step 166 is executed next.

In step 166, it is determined whether the vehicle has started. The SS leakage inspection is desirably performed while the vehicle is stopped. Therefore, if it is determined in step 166 that the vehicle has started, the routine of this time is immediately terminated after the processing of step 163 is executed. On the other hand, if it is determined in this step 166 that the vehicle has not started, the next step 16
8 is executed.

At step 168, it is determined whether an abnormality has occurred in the brake hydraulic pressure control system.
As a result, when it is determined that an abnormality has occurred in the system, it is appropriate to immediately terminate the SS leakage inspection. Therefore, when such a determination is made in step 168, the process of step 163 is executed, and then the current routine ends. On the other hand, if it is determined in step 168 that no abnormality has occurred in the system, the process of step 170 is executed next.

At step 170, the counter SSCNT
Whether or not a predetermined time T ₁ is counted is determined by.
If a leakage failure has occurred in SS58, after the SS leakage failure has started, the differential pressure generated on both sides of SS58 is gradually reduced. The above-mentioned predetermined time T ₁ is a time required for sufficiently reducing the differential pressure due to a leakage failure of SS58.

Therefore, in step 170, SSCNT
If it is determined that ≧ T ₁ is not established, it can be determined that the time required to detect the leakage failure of SS58 has not yet elapsed after the SS leakage inspection has been started. In this case, following step 170, the processing of step 162 and subsequent steps is executed again. On the other hand, if it is determined in step 170 that SSCNT ≧ T ₁ holds, it can be determined that the time necessary to detect the leakage failure of SS58 has already passed. In this case, the process of step 172 is performed after step 170.

At step 172, processing for completing the SS leakage inspection is executed. Specifically, in this step 172, the process of terminating the execution of the SS leakage inspection, resetting the start condition flag XTESTSS to “0”, and setting the inspection completion flag XSSFIN to “1” are executed. Is done. Step 17
When the processing of step 2 is completed, the current routine is terminated.

FIG. 8 shows a flowchart of a control routine executed by the ECU 10 to determine whether or not a leakage failure has occurred in the SS 58 based on the result of the SS leakage inspection. The routine shown in FIG. 8 is a periodic interruption routine that is started every predetermined time. When the routine shown in FIG. 8 is started, first, the process of step 174 is executed.

In step 174, it is determined whether the SS leakage inspection has been completed. Specifically, it is determined whether or not “1” is set to the inspection completion flag XSSFIN. As a result, if it is determined that XSSFIN = 1 is not established, the current routine is terminated without any further processing. On the other hand, XSSFIN
If it is determined that = 1 holds, then step 17
6 is executed.

In step 176, it is determined whether or not the following conditions are satisfied. PREG <PRWSS + P ₁ (1) PRW> PRWSS + P ₂ (2) In the condition of the above equation (1), the regulator pressure PREG is greatly increased with respect to the initial value PRWSS of the hydraulic pressure PRW. This is the case when there is no, that is, when the brake pedal 11 has not been depressed significantly after the SS leakage inspection has started. Also, the condition of the above equation (2) is that the hydraulic pressure PRW
Is established when the SS leakage inspection is started and then greatly increased.

In the brake fluid pressure control device of the present embodiment, when no leakage failure has occurred in SS58, the brake fluid pressure PRW is not greatly depressed.
Is not greatly increased. Therefore, if the conditions of the above equations (1) and (2) are both satisfied, SS58
It can be determined that a leak failure has occurred. Step 1 above
If such a determination is made in step 76, then step 1
The process of 78 is executed.

In step 178, it is stored that the leakage failure has occurred in SS58. After the process of step 178 is executed, the ECU 10 thereafter executes a process for notifying the driver of the vehicle of the occurrence of the leak. In step 180, the inspection completion flag XSSFIN is set to "0".
Is performed. After the process of step 180 is executed, it is determined that the condition of step 174 is not always satisfied. When the process of step 180 is completed, the current routine is completed.

If it is determined in step 176 in this routine that at least one of the conditions of the above equations (1) and (2) is not satisfied, the processing of step 182 is executed next. In step 182, it is determined whether all the following conditions are satisfied. PREG ≧ PRWSS + P ₃ (3) PREG-PRW <POFSS-P ₄ (4) PREG-PRW <P ₅ (5) The condition of the above equation (3) is that the regulator pressure PREG is The regulator pressure PREG is equal to the initial value PRWS of the hydraulic pressure PRW.
This holds when the pressure is significantly increased with respect to S, that is, when the brake pedal 11 is further depressed after the SS leakage inspection is started. The condition of the above equation (4) is that the pressure difference between the regulator pressure PREG and the hydraulic pressure PRW is equal to the initial value POF.
This holds when the value is significantly reduced as compared with SS. The condition of the above equation (5) is satisfied when the pressure difference between the regulator pressure PREG and the hydraulic pressure PRW is sufficiently small.

If the brake pedal 11 is further depressed in a situation where no leakage failure has occurred in SS58, a differential pressure close to the maximum relief pressure of the SLA 28 should be generated on both sides of SS58. Under such circumstances, if the pressure difference between PREG and PRW is smaller than the initial value POFSS, and it is determined that the pressure difference is sufficiently small, SS
58 can be determined to have a leak failure. Therefore, if such a determination is made in step 182, the process of step 178 is executed thereafter.

By the way, in this embodiment, SS58
In order to increase the detection accuracy of the leak failure of the above, the condition of the above formula (4) and the condition of the above formula (5) are used in combination. It can be recognized that one of the conditions of the above equation (4) and the above equation (5) is satisfied. Therefore, in step 182, the occurrence of a leak failure may be determined when one of the conditions of the above formulas (4) and (5) is satisfied together with the condition of the above formula (3).

If it is determined in step 176 in this routine that at least one of the conditions of the above equations (3) to (5) is not satisfied, then the processing of step 184 is executed. In step 184, it is determined whether all the following conditions are satisfied. POFSS ≦ P ₆ (6) PREG> PREGSS + P ₇ (7) PREG-PRW <P ₈ (8) The condition of the above equation (6) is the time when the SS leakage inspection is started. Holds when the differential pressure between PREG and PRW is already a small value. The condition of the above equation (7) is satisfied when the brake pedal 11 is further depressed to an extent that PREG rises to some extent after the SS leakage inspection is started. Further, the condition of the above equation (8) is satisfied when the pressure difference between PREG and PRW does not appropriately increase even though the brake pedal 11 is depressed.

If no leakage failure has occurred in SS58, PREG and PRW at the time when SS leakage inspection is started.
If the brake pedal 11 is further depressed to such an extent that PREG rises even if the differential pressure with
A differential pressure close to the maximum relief pressure of the SLA 28 should occur on both sides of S58. Under such circumstances, PREG and P
If the pressure difference from the RW is determined to be sufficiently small, SS
58 can be determined to have a leak failure. Therefore, when such a determination is made in step 184, the process of step 178 is executed thereafter.

On the other hand, if it is determined that none of the conditions of steps 176, 182 and 184 are satisfied,
It can be determined that no leakage failure has occurred in SS58. In this case, the process of step 186 is executed after step 184. In step 186, SS
58 is recognized to be normal. This step 186
Is completed, the process of step 180 is executed, and then the current routine is terminated.

According to the above-described processing, without turning on / off the control valve and without flowing a large amount of brake fluid, immediately after the IG switch is turned on, a leakage failure occurs in SS58 immediately. Whether it has occurred can be determined. Therefore, according to the brake fluid pressure control device of the present embodiment, after the vehicle is started, the leakage failure of the SS 58 can be accurately detected by a simple operation without impairing the silence.

In the above embodiment, the master cylinder 14 and the regulator 15 correspond to the "hydraulic pressure source" according to the third aspect, the SS 58 corresponds to the "separation valve" according to the third aspect, and the SMC _- 188 SMC _- 290 corresponds to the "hydraulic cutoff valve" according to the third aspect, SLA28 corresponds to the "relief valve" according to the third aspect, and the ECU 10 sets the IG switch to the ON state. After that, by maintaining the brake fluid pressure control device in the normal state, the "inspection state forming means" according to the third aspect executes the processing of the steps 156 to 180, thereby executing the "steps 156 to 180". "Leakage failure detecting means" are each realized.

[0125]

As described above, according to the first and third aspects of the present invention, a failure occurs in the separation valve that separates the hydraulic circuit of the brake hydraulic pressure control device into two systems. Can be accurately detected. According to the second aspect of the present invention, it is possible to reliably detect the leakage failure of the separation valve and to surely prevent the generation of a loud noise accompanying the leakage failure detection processing.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a brake fluid pressure control device according to a first embodiment and a second embodiment of the present invention.

FIG. 2 is a flowchart of a control routine executed in the first embodiment of the present invention to determine whether an SS leakage inspection start condition is satisfied.

FIG. 3 is a flowchart (part 1) illustrating a series of processes executed in accordance with the SS leakage inspection in the first embodiment of the present invention.

FIG. 4 is a flowchart (part 2) illustrating a series of processes executed in accordance with the SS leakage inspection in the first embodiment of the present invention.

FIG. 5 is a time chart for explaining the operation of the first embodiment of the present invention.

FIG. 6 is a flowchart of a control routine that is executed to determine whether the SS leakage inspection start condition is satisfied in the second embodiment of the present invention.

FIG. 7 is a flowchart of a control routine executed to determine whether or not SS leakage inspection has been completed in a second embodiment of the present invention.

FIG. 8 is a flowchart of a control routine executed to determine whether or not a leakage failure has occurred in a separation valve (SS) in a second embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 Electronic control unit (ECU) 11 Brake pedal 14 Master cylinder 15 Regulator 28 Linear control valve for pressure increase 36 Linear control valve for pressure reduction 58 Separation valve (SS) 88 First master cut valve (SMC _-1 ) 90 Second master cut valve (SMC- ₂ ) PREG regulator pressure PMC master cylinder pressure PRW, PFW hydraulic pressure

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shoichi Miyago 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (3)

[Claims] An isolation valve is provided between a first system communicating with a hydraulic pressure source and a second system communicating with a hydraulic pressure source, and at least one of the first system and the second system. One is a brake fluid pressure control device including a fluid pressure cut valve between the fluid pressure source and the separation valve, wherein the separation valve and the fluid pressure cut valve are both closed, and a closed circuit is provided between them. Closed-circuit forming means for forming, a hydraulic pressure control means for changing a hydraulic pressure supplied from the hydraulic pressure source side to the separation valve in a state where the closed circuit is formed, and the hydraulic pressure control means A brake fluid pressure control device, comprising: leak failure detection means for detecting leakage of the separation valve based on a fluid pressure change occurring in the closed circuit when changing a fluid pressure. 2. The brake fluid pressure control device according to claim 1, wherein the closed circuit forming means forms the closed circuit under a condition in which the initial circuit pressure higher than the atmospheric pressure can be stored in the closed circuit. And the hydraulic pressure control means changes the hydraulic pressure supplied to the separation valve after the closed circuit is formed to a lower hydraulic pressure than the initial hydraulic pressure. Brake fluid, comprising: a hydraulic pressure reducing unit configured to cause the control unit to perform a process necessary for detecting a leakage of the separation valve when the initial hydraulic pressure exceeds a predetermined value. Pressure control device. 3. A system according to claim 1, further comprising a separation valve between a first system communicating with the hydraulic pressure source and a second system communicating with the hydraulic pressure source, wherein at least one of the first system and the second system is provided. A hydraulic pressure cutoff valve is provided between the hydraulic pressure source and the separation valve, and at least the other of the first system and the second system is provided between the hydraulic pressure source and the separation valve. In a brake fluid pressure control device including a relief valve that allows a fluid flow from a pressure source side to the separation valve side, a fluid higher than atmospheric pressure from the fluid pressure source to the relief valve and the fluid pressure cut valve is provided. Under pressure conditions,
Inspection state forming means for forming an inspection state by closing the separation valve and opening the hydraulic pressure cut valve, and generated on both sides of the separation valve when the inspection state is realized. And a leakage failure detecting means for detecting leakage of the separation valve based on the differential pressure.