JP2000272496A - Vehicle behavior control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To minimize the time required for self-diagnosis of a hydraulic system. A precharge pressure generating operation is started by driving a motor M to close a piston stroke adjusting valve 24, and the pressure detection value pp is precharged from the time when the pressure detection value pp of the pressure sensor 16 starts to increase. Based on the time required to reach the minimum pressure value P _MIN of the pressure variation, the time required for the detected pressure value pp to reach the maximum pressure value P _MAX of the variation is calculated, and this is calculated as the estimated time T to reach the upper limit value. _{Assume 3} . Since the upper limit value reaching estimated time T ₃ is a time until the pressure detected value pp reaches the pressure detected value P _MAX at the latest when the pressure detected value pp continues to increase with the increase gain at the time of the rise, the estimated upper limit value reaching time T ₃ When the T ₃ has passed, if the pressure detection value pp does not exceed the maximum pressure value P _MAX, the pressure detection value pp can be considered stable, therefore, the hydraulic system a hydraulic circuit including the pressure sensor 16 Is determined to be normal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle behavior control device that generates a braking force to stabilize vehicle behavior.

[0002]

2. Description of the Related Art Various types of vehicle behavior control devices of this type have been proposed. For example, a target value of a vehicle behavior such as a yaw rate, a side slip angle or a side slip speed is calculated based on a vehicle model. Detects actual values of vehicle behavior such as yaw rate, sideslip angle or sideslip speed occurring in the vehicle,
According to the deviation between the two, for example, in order to obtain a force that matches the actual value of the vehicle behavior to the target value, the braking force of each wheel,
That is, the brake fluid pressure to the brake cylinder is controlled. According to such a vehicle behavior control device, for example, when the vehicle enters a turning state exceeding the limit of the grip of the tire such as extreme oversteer or understeer, for example, the actual value of the yaw rate is set to the target value. As a result, a moment is generated by controlling the braking force of each wheel so that the vehicle can always be driven in the grip area of the tire, and undesired turning such as extreme oversteer or understeer can be performed. The behavior can be prevented and suppressed.

[0003]

When such vehicle behavior control is performed, the brake cylinder of each wheel is connected to, for example, a two-system output master cylinder having ordinary front and rear piping,
A hydraulic pressure control unit for controlling vehicle behavior is provided between these braking fluid pressure sources and the braking cylinders by connecting a master cylinder or a pressure increasing pump or the like as a pressure source to each system. The braking force generated by the brake cylinder is controlled by increasing / decreasing the braking fluid pressure by the hydraulic pressure control unit.

[0004] In addition, since high control responsiveness is required, for example, Japanese Patent Application No. P11-2322, which has not been disclosed yet.
As described in No. 7, vehicle behavior in which a control unit for generating a predetermined pressure and applying the predetermined pressure to the suction side of the pressure boosting pump is provided in order to improve the initial pressure response of the pressure boosting pump. Control devices have also been proposed. In such a vehicle behavior control device, it is necessary to monitor an abnormality of the entire vehicle behavior control system because of fail safety. For example, abnormality detection of a pressure increasing pump, a motor for operating the pump, a hydraulic control unit, or the like. Need to do. For this reason, for example, when the engine is started, it is necessary to detect an abnormality by driving the motor and detecting whether the fluid pressure detected by the pressure sensor at this time is a predetermined value.

However, it takes time from the start of the motor to the stabilization of the fluid pressure. Therefore, it takes a certain amount of time to detect an abnormality. During this time, vibration or noise of the motor is generated. It is desired to reduce the driving time of the motor as much as possible. Therefore, the present invention has been made in view of the above-mentioned conventional unsolved problem, and an object of the present invention is to provide a vehicle behavior control device capable of minimizing the time required for failure diagnosis.

[0006]

To achieve the above object, a vehicle behavior control apparatus according to a first aspect of the present invention includes a booster pump for increasing a working pressure to a brake cylinder. A preload applying means for applying a predetermined preload; a pressure sensor capable of detecting a discharge pressure of the preload applying means; and a pressure sensor based on whether a pressure detection value of the pressure sensor is within a predetermined range of the preload variation. Diagnosis means for performing a failure diagnosis, based on the time required from when the preload applying means is activated until the pressure detection value of the pressure sensor reaches a preset minimum value of the variation of the preload, the pressure detection value is An estimating means for estimating a time required to reach a maximum value of the variation of the preload, wherein the diagnosing means passes the estimated time estimated by the estimating means. Is characterized that it is so when the a determination of the fault diagnosis.

Further, in the vehicle behavior control device according to the present invention, the estimating means may include a time required for the detected pressure value to start to increase and reach the minimum value, and a maximum value and a minimum value of the variation. The estimation time is estimated based on the ratio of Also,
The vehicle behavior control device according to claim 3, wherein the diagnosis unit includes:
It is characterized in that the determination is made at the latest when a preset minimum value arrival time has elapsed.

Furthermore, in the vehicle behavior control device according to a fourth aspect, the minimum value reaching time is set based on a time required until the pressure detection value reaches the minimum value in a low temperature environment. It is characterized by:

[0009]

According to the vehicle behavior control device according to the first aspect of the present invention, the maximum value of the preload variation is determined based on the time required for the pressure detection value of the pressure sensor to reach the minimum value of the preload variation. Since the time required to reach the estimated time is estimated, and the determination is made when the estimated time has elapsed, the time required for the failure diagnosis can be reduced, and the driving of the preload applying means accompanying the failure diagnosis can be reduced. Time can be reduced.

Further, according to the vehicle behavior control device of the second aspect, after the pressure detection value of the pressure sensor starts to increase,
The time required to reach the minimum preload variation,
Since the estimated time is estimated based on the ratio between the maximum value and the minimum value of the preload variation, an accurate estimated time can be obtained. Further, according to the vehicle behavior control device of the third aspect, the diagnosis unit performs the determination at the latest when the minimum value arrival time has elapsed, so that the failure diagnosis is not performed for a long time. can do.

Further, according to the vehicle behavior control device of the present invention, the minimum value arrival time is set based on the required time in a low temperature environment, so that accurate determination can be made even at a low temperature. be able to.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a hydraulic system of a vehicle behavior control device according to the present invention. 1FL, 1 in the figure
RR indicates a front left wheel and a rear right wheel, respectively, 1FR, 1RL
Indicates a front right wheel and a rear left wheel, respectively. Then, wheel cylinders 2FL to 2RR as braking cylinders are attached to the respective wheels 1FL to 1RR. Note that each of the wheel cylinders 2FL to 2RR is a so-called disc brake, in which a pad is attached to a disc rotor for braking.

The master cylinder 5 generates two systems of master cylinder pressure in response to depression of the brake pedal 4. The connection structure between the wheel cylinders 2FL to 2RR is such that the front left wheel cylinder 2FL and the rear left wheel cylinder 2RL are connected to one system of the master cylinder 5, and the front right wheel cylinder 3FR and the rear right wheel are connected to the other system. The wheel cylinder 2RR is connected.

First, similarly to the conventional anti-lock brake system, the pressure increase control corresponding to the upstream side of each of the wheel cylinders 2FL, 2RL or 2FR, 2RR connected to each system of the master cylinder 5 is performed. The valve 8FL, 8RL or 8FR, 8RR is inserted.
The brake fluid pressure upstream of these pressure increase control valves 8FL to 8RR is also referred to as a line pressure for convenience. In addition, check valves 9FL, 9RL or 9FR, 9RR are provided in the bypass passages of these pressure increase control valves 8FL, 8RL or 8FR, 8RR so that the wheel cylinder is released when the depression of the brake pedal 4 is released. The braking fluid in 2FL, 2RL or 2FR, 2RR is immediately returned to the master cylinder 5 side.

The discharge side of each of the main pumps 11 LH and 11 RH is connected to each system of the master cylinder 5, and their suction sides and the wheel cylinder 2 are connected to each other.
Pressure reducing control valve 1 between FL, 2RL or 2FR, 2RR
Insert 0FL, 10RL or 10FR, 10RR.
The two main pumps 11LH and 11RH also serve as one pump motor M. In addition, each pressure reducing control valve 10F
L, 10RL or 10FR, 10RR and main pump 11L
H and 11RH are connected to reservoirs 18LH and 18RH. A main pump 11L is provided between each reservoir 18LH, 18RH and the main pump 11LH, 11RH.
H, a check valve 26LH that shuts out the flow from the 11RH side,
26RH is inserted.

On the other hand, as in a so-called traction control system, even when there is no braking input by the driver, the suction side of the main pumps 11LH and 11RH is provided so that line pressure can be supplied instead of the master cylinder 5. The master cylinder reservoir 5a is connected via the gate-in valves 7LH and 7RH. The main pump 11L
Non-return valves 25LH, 25RH for blocking outflow from the main pumps 11LH, 11RH are interposed between H, 11RH and the respective gate-in valves 7LH, 7RH. Further, in order to prevent the line pressure created by each of the main pumps 11LH and 11RH from being returned to the master cylinder 5 side by the brake fluid sucked from the master cylinder reservoir 5a, the connection between the main pumps 11LH and 11RH and the master cylinder 5 is prevented. Are inserted through check valves 22LH and 22RH, and gate-out valves 6LH and 6RH are inserted into the bypass circuit.

Between each of the gate-in valves 7LH, 7RH and the master cylinder reservoir 5a, there are provided two systems of auxiliary pumps 3LH, 3RH for sucking and pressurizing the brake fluid of the master cylinder reservoir 5a and a line pressure. The main pump 11LH, 1
The precharge pistons 20LH and 20RH for improving the initial pressure response of 1RH are interposed, and the discharge pressure of the auxiliary pumps 3LH and 3RH is used as a piston stroke input of the precharge pistons 20LH and 20RH. And this precharge piston 20LH, 2
A relief valve 21L that regulates the discharge side pressure of the main pumps 11LH, 11RH, that is, the line pressure, between the discharge side of 0RH and the discharge side of the main pumps 11LH, 11RH.
H, 21RH are inserted.

The auxiliary pumps 3LH and 3RH are
The pump motor M of the main pumps 11LH and 11RH is shared. The discharge pressures of the auxiliary pumps 3LH and 3RH are joined again. Therefore, the discharge pressures of the auxiliary pumps 3LH and 3RH, which are the piston inputs of the precharge pistons 20LH and 20RH, are reduced by the auxiliary pump 3L.
The pressure is regulated by a piston stroke adjusting valve 24 and a relief valve 23 interposed between the discharge side and the suction side of H, 3RH.

The precharge piston 20LH,
The pressure at the piston input side of 20 RH, that is, the auxiliary pump 3
LH, the pressure discharge pressure of the master cylinder pressure input side of 3RH, that is, when greater than the true master cylinder pressure P _MC in accordance with the depression amount of the brake pedal 4 is precharged piston is moved to the left in FIG. 1 Piston 2
The discharge pressures of 0LH and 20RH are equal to the auxiliary pumps 3LH and 3R.
Discharge pressure of H that is, the pre-charge pressure P _{P / P,} and conversely, the true master cylinder pressure P _MC is auxiliary pump 3LH, 3
When the pressure is higher than the discharge pressure of RH, the piston moves rightward in FIG.
Discharge pressure of 20RH, the master cylinder pressure P _MC, and the other words, the precharge piston 20LH, the discharge pressure of 20RH, the master cylinder pressure and the auxiliary pump 3LH, so the larger one of the discharge pressure of 3RH I have.

Each of the above-mentioned pressure control valves is a two-position solenoid-operated switching valve which is switched by a drive signal from a control unit to be described later. For fail-safe operation, for example, the gate-out valves 6LH and 6RH are always open and the gates are open. The inlet valves 7LH and 7RH are normally closed, and the pressure increase control valve 8F
L, 8RL or 8FR, 8RR is always open, pressure reducing control valve 1
0FL, 10RL or 10FR, 10RR are always closed, and when the solenoid of each electromagnetic switching valve is excited by the drive signal, the state is switched to the opposite open / closed state. The auxiliary pumps 3LH and 3RH and the main pump 11L
H, 11RH or the piston stroke adjusting valve 24 is also driven and controlled by a driving signal from the control unit.

Therefore, in this hydraulic system, when controlling the braking force for performing the vehicle behavior control described later, the braking fluid pressure (hereinafter, referred to as the braking fluid pressure) of each of the wheel cylinders 2FL to 2RR.
Also referred to as wheel cylinder pressure. )
For example, when the gate-out valves 6LH and 6RH are closed and the gate-in valves 7LH and 7RH are open, the main pump 11LH and 6RH are opened.
11RH, and controls the discharge pressure, that is, the line pressure, to open the pressure increase control valves 8FL to 8RR while the pressure reduction control valves 10FL to 10RR are closed.
Supply to FL ~ 2RR.

Each of the wheel cylinders 2FL-2FL
In order to reduce the wheel cylinder pressure after the RR wheel cylinder pressure is increased, for example, the gate-out valve 6
The main pumps 11LH and 11RH are driven in a state where the LH and 6RH are closed and the gate-in valves 7LH and 7RH are closed, and the pressure-decreasing control valve 10FL is driven while each of the pressure-increasing control valves 8FL to 8RR is closed.
Open control of 10 RR to 10 RR for each wheel cylinder 2 FL
Drain the brake fluid in 2RR.

The opening control of each of the pressure increase control valves 8FL to 8RR and the pressure reduction control valves 10FL to 10RR will be described later. The opening / closing control of the gate-in valves 7LH and 7RH and the gate-out valves 6LH and 6RH is performed according to, for example, an individual calculation process (not shown) performed using the line pressure at that time. In order to reduce the reaction force to the brake pedal 4, the gate-out valves 6LH and 6RH may be opened when the brake pedal 4 is depressed. Further, increasing the braking force and reducing the braking fluid pressure (wheel cylinder pressure) have the same meaning, and henceforth, both will be treated synonymously.

[0024] Figure 2, there is shown a block diagram of a control system of the vehicle behavior control device according to the present invention, the each wheel 1FL~1RR the wheel speed Vw _i (i corresponding to the rotational speed of the wheel = FL to RR) (hereinafter, also referred to as wheel speed). Wheel speed sensors 12FL to 12RR are attached. Further, the vehicle includes a yaw rate sensor 13 for detecting an actual yaw rate φ ′ generated in the vehicle, a steering angle sensor 14 for detecting a steering angle θ of a steered wheel from a steering angle of a steering wheel, and a lateral acceleration Y _G generated in the vehicle. an acceleration sensor 15 for detecting a longitudinal acceleration X _G, logic detects the depression of the brake pedal 4, which shows the OFF state when not the logical value "1", depressed indicating the oN state when the brake pedal is depressed A brake switch 17 or the like that outputs a brake switch signal S _BRK having a value “0” is attached, and the detection signals of the respective sensors and switches are all input to a control unit 19 described later. Further, a pressure sensor 16 for detecting the discharge pressure of the precharge piston 20LH is provided between the precharge piston 20LH and the gate-in valve 7LH.
Is input to

[0025] The control unit 19 inputs a state signal S _IG of the detection signal and the ignition switch SW from the sensors and switches described above, outputs a control signal of said each switching valve for the vehicle behavior control And a drive circuit that converts a control signal output from the microcomputer into a drive signal for each control valve solenoid including the above-described electromagnetic switching valve and the like. And the microcomputer is A
An input interface circuit having a / D conversion function, etc.
An output interface circuit having an / A conversion function and the like, an arithmetic processing unit including a microprocessor unit MPU and the like, and a storage device including a ROM and a RAM are provided.

The control unit 19 estimates the master cylinder pressure corresponding to the amount of depression of the brake pedal 4 of the master cylinder 5 based on the detection signals from the sensors and switches, and calculates the estimated master cylinder pressure. A master cylinder pressure estimating unit 19a for setting the pressure _PMC ^* and a vehicle behavior control unit 19b for performing vehicle behavior control using the estimated master cylinder pressure _PMC ^* estimated by the master cylinder pressure estimating unit 19a are provided. .

In the master cylinder pressure estimating section 19a,
The pressure detection value pp from the pressure sensor 16 and the brakes
Brake switch signal S from switch 17_BRK, Vehicle lift
VDC operation flag F set by the motion control unit 19b_VDCAlso
In addition, the master system according to the amount of depression of the brake pedal 4
Estimate the cylinder pressure. That is, the VDC operation flag F
_VDCIs off, the pressure detection value pp is
Pressure P_MC ^*VDC operation flag F_VDCBut
When in the ON state, for example, the brake switch signal
S_BRKIs off, the master cylinder pressure P_MC ^*Is zero
And the brake switch signal S_BRKIs turned on,
Precharge pressure P_{P / P}Predetermined value p smaller than_XThe master
Cylinder pressure P_MC ^*And the detected pressure value pp increases,
Precharge pressure P set_{P / P}Greater than threshold
When this state continues for a predetermined time after exceeding α
The detected value pp is changed to the master cylinder pressure P_MC ^*And And
Wait until the pressure detection value pp becomes smaller than the threshold value α.
When a predetermined time elapses, the predetermined value p_XThe master
Linda pressure P_MC ^*And the brake switch signal S_BRKBut
Master cylinder pressure P_MC ^*Is assumed as zero
Is to be specified.

On the other hand, the vehicle behavior control section 19b is provided with the wheel speed sensor 1 in the same manner as a known vehicle behavior control device.
A wheel speed Vw _i from 2FL～12RR, the actual yaw rate phi 'from the yaw rate sensor 13, steering angle sensor 14
And the lateral acceleration Y _G from the acceleration sensor 15
And the longitudinal acceleration _XG, and the master cylinder pressure estimating unit 1
The control yaw moment for stabilizing the vehicle behavior is calculated based on the estimated master cylinder pressure P _MC ^* estimated in 9a and the like, and is required to add the calculated control yaw moment to the current vehicle behavior. Calculate the pressure increase / decrease amount of each wheel cylinder pressure, and control each of the pressure increase control valves 8FL to 8RR and the pressure reduction control valves 10FL to 10RR in accordance with the pressure increase / decrease amount, for example, to adjust the wheel cylinder pressure of the turning inner wheel or the outer wheel. The pressure is increased or decreased by a predetermined pressure.

If necessary, the motor M is driven while the piston stroke adjusting valve 24 is closed, the gate-out valves 6LH, 6RH are closed, and the gate-in valves 7LH, 7RH are open, to drive the main pumps 11LH, 11RH. Drive the
Further, the auxiliary pumps 3LH and 3RH are driven to improve the initial pressure response of the main pumps 11LH and 11RH, and the discharge pressure of the main pumps 11LH and 11RH is used as a brake fluid pressure source to the wheel cylinders 2FL to 2RR. It has become. And the auxiliary pumps 3LH and 3RH
Is activated and the discharge pressure of the auxiliary pumps 3LH, 3RH is acting on the piston input side of the precharge pistons 20LH, 20RH, the VDC operation flag F _{VDC is set} to F
_VDC = 1, and when the discharge pressure of the auxiliary pumps 3LH and 3RH is not acting on the piston input side, F
_VDC = 1 is set.

The vehicle behavior control section 19b performs a self-diagnosis process for performing a failure diagnosis of the hydraulic system shown in FIG. 1, that is, a hydraulic circuit including the pressure sensor 16 at the time of startup. FIG. 3 is a flowchart showing a processing procedure of the self-diagnosis processing. This self-diagnosis processing is executed, for example, as a timer interrupt every predetermined time. The flags under processing and the count value T are set to zero at startup.

In this self-diagnosis processing, first, in step S
At 1, it is determined whether the self-diagnosis has already been completed. This determination is made based on a self-diagnosis flag F _TEST that is set in a process described later and that indicates whether the self-diagnosis has been completed. When the self-diagnosis flag is F _TEST = 1, it is determined that the self-diagnosis has already been completed, and the self-diagnosis processing ends. On the other hand, when the self-diagnosis flag is F _TEST = 0, it is determined that the self-diagnosis has not been completed, and the process proceeds to step S2.

In this step S2, it is determined whether or not a preset self-diagnosis start condition is satisfied. This self-diagnosis start condition is, for example, the ignition switch S
Whether W is in the ON state and the vehicle speed is equal to or higher than a predetermined value, and so on. Incidentally, the vehicle speed, for example, may be calculated based on the wheel speed Vw _i from the wheel speed sensors 12FL～12RR. When the self-diagnosis start condition is not satisfied, the self-diagnosis processing ends.

On the other hand, when the self-diagnosis start condition is satisfied, the flow shifts to step S3 to perform a precharge pressure generating operation. That is, the motor M is driven and the auxiliary pump 3L is driven.
H, 3RH are driven, and the piston stroke adjusting valve 24 is closed. Next, the process proceeds to step S4 to determine whether or not the detected pressure value pp has already _exceeded the minimum pressure value _PMIN . This determination is made based on a minimum value flag F _MIN that is set in a process described later and indicates whether the detected pressure value pp has already _{exceeded the} minimum pressure value P _MIN . The minimum pressure value P _MIN is the precharge pressure P
_{When generating P / P} , this is the minimum value of the variation of the precharge pressure that can be regarded as generating the normal precharge pressure, and the maximum value of this variation is defined as the maximum pressure value _PMAX .

At step S4, the minimum value flag is set to F
_If not _MIN = 1, the process proceeds to step S5, and F _MIN
If = 1, the process proceeds to step S11 described below.
In step S5, the detected pressure value pp is equal to the minimum pressure value P
_It is determined whether or not _MIN has been _exceeded . If pp> P _MIN , the process proceeds to step S6, and based on the following equation (1),
Estimating the upper limit arrival time T _2. This upper limit value arrival time T
₂ is the time when the operation of generating the precharge pressure is started (hereinafter, referred to as the time of starting the operation of generating the precharge pressure), that is, from the time when the motor M is turned on and the piston stroke adjusting valve 24 is closed. This is the time required for the detected pressure value pp to reach the maximum detected pressure value _PMAX .

T ₂ = (T ₁ −T ₀ ) × (P _MAX / P _MIN ) + T ₀ (1) In the equation, T ₀ is a pressure detection value pp from the start of the precharge pressure generation operation. Is a response time until the self-diagnosis process starts to increase, and is a value set in advance so that the self-diagnosis process does not malfunction. In the equation, T ₁ is the minimum pressure value P from the start of the precharge pressure generation operation.
_This is a time required to reach _MIN , and is a measured value based on a count value T set by a process described later.

Next, the process proceeds to step S7, where the minimum value flag F _MIN is set to F _MIN = 1. Then, control goes to a step S11. Meanwhile, in the above step S5, when the pressure detection value pp does not exceed the minimum pressure value P _MIN, the process proceeds to step S8, the upper limit estimated arrival time T ₂ the lower limit arrival time maximum value T ₃ set in advance Set as The maximum value T ₃ of the lower limit reaching time is the minimum pressure value P of the variation of the precharge pressure from the start of the precharge pressure generating operation when the hydraulic system is normal.
_MIN is the maximum value of the time required to reach _MIN , for example, the pressure detection value p
It is set in advance based on the time required until p reaches the minimum pressure value P _MIN .

[0037] Then, the process proceeds to step S9, determines whether the lower limit arrival time maximum value T ₃ has passed from the pre-charge pressure producing operation starting time. In other words, it determines whether the count value T to be set by the processing described later is T> T _3. Then, when not T> T ₃ Step S11
Proceeds to step described later when a T> T ₃ S1
Move to 5. In step S11, the count value T
To the original, to determine if the pre-charge pressure producing operation starting time, or the time of the smaller one of the upper limit estimated arrival time T ₂ and the lower limit arrival time maximum value T ₃ has elapsed (T>
MIN [T ₂ , T ₃ ]), when T> T ₂ and T> T ₃ are not satisfied, the process proceeds to step S12, and the counter value T is set to 1
Then, the self-diagnosis processing ends.

On the other hand, when the counter value T is larger than the smaller one of the estimated upper limit value arrival time T ₂ and the lower limit arrival time maximum value T ₃ in step S 11, the process proceeds to step S 13, and the pressure detection value is determined. pp determines whether exceeds a maximum pressure value P _MAX. If pp> _PMAX , the process proceeds to step S15, and the result of the self-diagnosis is determined to be abnormal, and the failure flag F _{FAIL is set} to F _FAIL
Then, the process proceeds to step S16. If pp> _PMAX is not satisfied in step S13, the result of the self-diagnosis is determined to be normal, and the process directly proceeds to step S16.

In step S16, the motor M is turned off and the piston stroke adjusting valve 24 is opened.
Stop generation of precharge pressure. And step S
7 and set the self-diagnosis end flag F _TEST to F _TEST = 1
Then, the self-diagnosis processing ends. Here, the drive of the motor M and the auxiliary pumps 3LH and 3RH correspond to the preload applying means, and the self-diagnosis processing of FIG.
The processing in step S6 in FIG. 3 corresponds to the estimating means.

Next, the operation of the above embodiment will be described with reference to a time chart shown in FIG. In FIG. 4, (a) shows the operating state of the motor M, and the operating state is represented by the H level. (B) shows the state of the piston stroke adjusting valve 24, in which the closed state is represented by the H level. (C) is a detected pressure value pp of the pressure sensor 16, wherein a solid line represents a normal time and a broken line represents an abnormal time. (D) represents a minimum value flag F _MIN ,
(E) represents a fail flag F _FAIL .

When activated, the vehicle behavior control section 19b executes the self-diagnosis processing shown in FIG. 3 at a predetermined interruption timing. When the ignition switch SW is turned on at time t ₁ and the vehicle starts moving and the vehicle speed becomes equal to or higher than a predetermined value and a predetermined self-diagnosis start condition is satisfied, the process proceeds to step S3 via steps S1 and S2. Then, the motor M is turned on, the piston stroke adjusting valve 24 is closed, the precharge pressure generating operation is started, and the auxiliary pumps 3LH and 3RH are started.

Since there is a response dead time from the start of the auxiliary pumps 3LH and 3RH to the change of the fluid pressure at the position of the pressure sensor 16, the pressure at the position of the pressure sensor 16 is still maintained at zero at this time. since a state shifts to step S8 through step S4, S5, the maximum value T ₃ lower limit arrival time set in advance is set as the upper limit value estimated arrival time T _2. And step S
9, the process proceeds to step S11, and the count value T is incremented by one.

This process is repeated, and the time t₁From
Precharge pressure response dead time T₀This lapse after
Time t_TwoIncreases the pressure detection value pp of the pressure sensor 16
Begin to. And time t_ThreeIs the minimum pressure value pp
Force value P_MINTo step S6 from step S5
Then, based on the above equation (1), the estimated upper limit value arrival time T_TwoBut
Is calculated. That is, as indicated by a straight line L in FIG.
Point t_TwoFrom time t_ThreeThe pressure detection value pp is between zero and minimum during
Pressure value P_MINUp to the straight line L
If the pressure rises with a slope of
Pressure value P _MAXEstimate how long it takes to reach
Based on this, the estimated upper limit value arrival time T_Two
Can be estimated.

Then, the minimum value flag F_MINIs F_MIN= 1
(Step S7), and through Step S11
In step S12, the counter value T is incremented.
You. If the hydraulic system shown in FIG. 1 is normal,
As shown by the solid line in FIG.
Value within the range of pressure variation, that is, the maximum pressure value P
_MAXAnd P_MINAnd settle to a value between. Therefore, cow
Event value T is the estimated upper limit time T_TwoAt time t_Five
Then, the detected pressure value pp is the maximum pressure value P_MAXIs less than
From step S13 to step S16,
Drive M is stopped, and the piston stroke adjusting valve 24 is opened.
As a state, the generation of the precharge pressure is stopped. Soshi
The self-diagnosis end flag F_TESTSet to 1 (Step
Step S17). Thereafter, the self-diagnosis processing of FIG. 3 is performed.
The self-diagnosis end flag F_TESTIs set to 1
The self-diagnosis has already been performed in the process of step S1.
The self-diagnosis is not performed.

On the other hand, some abnormality occurs in the hydraulic system, without stable within the range of variation of the pre-charge pressure, as indicated by a broken line in FIG. 4, the maximum pressure value detected pressure value pp is at t ₄ P If it exceeds _MAX , steps S13 to S1
Then, it is determined that some abnormality has occurred in the hydraulic system. Then, the fail flag F _FAIL becomes F _FAIL = 1
Is set, the motor M is turned off, the piston stroke adjustment valve 24 is controlled to be open (step S16), and the self-diagnosis end flag F _TEST is set to F _TEST = 1 (step S17).

That is, the estimated upper limit value arrival time T_TwoIs the pressure
The detection value pp changes from zero to the minimum pressure value P_{MI N}Until you reach
Set based on the increase gain of pressure detection value pp
Therefore, if the hydraulic system is normal, the count value T will be
Estimated upper limit value arrival time T_TwoAt which point (in this case,
Point T_Five) Contains the maximum pressure value P_MAXStable with the following values
And Therefore, the estimated upper limit value arrival time T_TwoHas passed
Time T_FiveAnd the detected pressure value pp is the maximum pressure value P_MAXTo
If not, the detected pressure value pp is the maximum pressure value P_MAXLess than
The value below can be considered stable, i.e. the hydraulic pressure
The system can be considered normal. Conversely, time T_Five
And the detected pressure value pp is the maximum pressure value P_MAXIs over
The precharge pressure is out of range
Therefore, it is detected as an abnormality of the hydraulic system.

When the pressure sensor 16 becomes abnormal and the detected pressure value pp remains zero, or when the hydraulic system becomes abnormal and the pressure at the position of the pressure sensor 16 does not increase. the equal, even starts precharge pressure producing operation at the time t _1, pressure detection value pp of the pressure sensor 16 remains zero. In this case, from the time point t ₁ when the precharge pressure generating operation is started, when the maximum value T ₃ reaches the lower limit value reaching time, the steps S 9 to S 15 are performed.
Then, it is determined that an abnormality has occurred in the hydraulic system, and the fail flag F _FAIL is set to F _FAIL = 1.

Further, for example, when the device is placed in an extremely low temperature environment, the response of the fluid pressure is lower than that at normal temperature, so that the pressure detection value pp may not reach the minimum pressure value _PMIN. Since the required time is required, the lower limit value reaching time T ₁ is increased, and the upper limit value reaching estimated time T ₂ calculated based on the lower limit time T ₁ is calculated.
Becomes longer. However, if the upper limit estimated arrival time T ₂ is longer than the maximum value T ₃ lower limit arrival time is in the process of step S11, either the maximum value T ₃ the upper limit estimated arrival time T ₂ and the lower limit value arrival time The determination is made when a short time has elapsed, and the determination is made based on the detected pressure value pp at this time.

As described above, based on the gain of the increase in the detected pressure value pp of the pressure sensor 16 from the start of the precharge pressure generating operation, that is, the estimated time to reach the upper limit value based on the fluid pressure response at the present time of the hydraulic system. calculating a T _2, it is so arranged makes a determination when this upper limit estimated arrival time T ₂ has elapsed, it is possible to make a determination when it becomes possible to detect an abnormality, required for fault diagnosis Processing time can be reduced. Further, the abnormality can be determined at an optimum time regardless of the change in the fluid pressure response caused by the change in the environmental temperature.

[0050] Also, a maximum time that the pressure detection value pp can reach a minimum pressure value P _MIN at low temperatures, the provided maximum value T ₃ lower limit arrival time, maximum value the lower limit arrival time T
Even if the pressure detection value pp has not reached the minimum pressure value P _MIN even after the elapse of ₃ , or if the pressure detection value pp has exceeded the minimum pressure value P _MIN , at the latest, the maximum value T for reaching the lower limit value is reached. _{Since the} abnormality determination is performed at the time when ₃ has elapsed, it is possible to prevent the abnormality determination processing from being performed for a long time.

Thus, since the processing time required for the abnormality determination can be shortened, the time for starting the motor M can be shortened, and accordingly, the noise or vibration associated therewith can be reduced. In particular, at normal temperature where the response of pressure is fast, since the response is higher than at low temperature,
The driving time of the motor M can be further reduced, which is effective.

In the above embodiment, when the smaller of the estimated upper limit value arrival time T _{2 and the} lower limit value arrival time maximum value T ₃ has elapsed, steps S 11 to S 1 are performed.
Case was described in which to perform the migration to abnormality determination second processing, but monitors the pressure detection value pp, whichever smaller upper limit estimated arrival time T ₂ or the lower limit arrival time maximum value T ₃ is Before the lapse of time, the detected pressure value pp becomes the maximum pressure value P
_If it exceeds _MIN , it may be determined at this point that it is abnormal.

In the above embodiment, the case where the pressure sensor 16 is provided between the precharge piston 20LH and the gate-in valve 7LH has been described. However, the pressure sensor is also provided on the discharge side of the master cylinder 5. even can be applied if, in this case, without estimating the master cylinder pressure P _MC, may be used to detect values of the pressure sensor provided on the discharge side of the master cylinder 5 as the master cylinder pressure.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of a hydraulic system of a vehicle behavior control device according to the present invention.

FIG. 2 is a block diagram illustrating an example of a control system of the vehicle behavior control device according to the present invention.

FIG. 3 is a flowchart illustrating an example of a processing procedure of a self-diagnosis processing in a control unit.

FIG. 4 is a time chart for explaining the operation of the present invention;

[Explanation of symbols]

 1FL to 1RR Wheel 2FL to 2RR Wheel Cylinder 3LH, 3RH Auxiliary Pump 4 Brake Pedal 5 Master Cylinder 6LH, 6RH Gate Out Valve 7LH, 7RH Gate In Valve 8FL to 8RR Pressure Increase Control Valve 10FL to 10RR Pressure Reduction Valve 11LH, 11R 12FL to 12RR Wheel speed sensor 13 Yaw rate sensor 14 Steering angle sensor 15 Acceleration sensor 16 Pressure sensor 17 Brake switch 19 Control unit 19a Vehicle behavior control unit 19b Master cylinder pressure estimation unit 20LH, 20RH Precharge piston 24 Piston stroke adjustment valve SW Ignition switch

Claims (4)

[Claims] 1. A pre-pressure applying means for applying a predetermined pre-pressure to a suction side of a boosting pump for increasing an operating pressure to a braking cylinder, a pressure sensor capable of detecting a discharge pressure of the pre-pressure applying means, Diagnosing means for performing a failure diagnosis based on whether or not the detected pressure value of the pressure sensor is within a preset range of the variation of the preload; and detecting the pressure detection value of the pressure sensor from the time when the preload applying means is activated. Estimating means for estimating the time required for the detected pressure value to reach the maximum value of the preload variation based on the time required to reach the minimum value of the set preload variation. A control device, wherein the diagnosis means is configured to make a determination of the failure diagnosis when an estimated time estimated by the estimation means has elapsed. Location. 2. The estimating means estimates the estimated time based on a required time from when the detected pressure value starts to increase to when the detected pressure value reaches the minimum value and a ratio between a maximum value and a minimum value of the variation. The vehicle behavior control device according to claim 1, wherein: 3. The vehicle behavior control device according to claim 1, wherein the diagnosis unit performs the determination at the latest when a preset minimum value arrival time has elapsed. 4. The apparatus according to claim 3, wherein the minimum value arrival time is set based on a time required until the pressure detection value reaches the minimum value in a low temperature environment. Vehicle behavior control device.