JPH10230838A - Vehicle brake controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a traveling feeling from being deteriorated and noise by ABS control of slow braking. SOLUTION: When wheels are getting excessively slipped by depressing of a brake pedal, ABS control is perfumed. In a pressure reducing mode of ABS control, slow braking is detected (YES in S150) by referring to master cylinder pressure if the wheels are in the control range. When the mode is transferred to a pulse increasing mode, if the pulse number is in the range of 3 to 7 (YES in S170), a value of master cylinder pressure PMCINT is stored in starting of an oil pressure stopping mode, the mode is transferred to the oil pressure stopping mode, and the normal adjustment of S/C oil pressure by ABS control is stopped (S180). Since the moderate W/C oil pressure is maintained in slow braking, the same oil pressure adjustment as that in sudden braking is not performed, and therefore, an operation feeling is improved. Since W/C oil pressure is not vibrational-fluctuatted, a vehicle is not longitudinally vibrated caused by fluctuation of braking force, and therefore, uncomfortablenss is not generated in braking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for braking a vehicle,
The present invention relates to a braking control device that is started when a wheel slip of a predetermined value or more is detected, and adjusts a braking force applied to wheels to execute a braking force control that causes a vehicle to perform high deceleration according to a road surface condition.

[0002]

2. Description of the Related Art An anti-lock brake system (hereinafter referred to as ABS) for preventing wheels from locking even when a sudden brake is applied on a slippery road such as a snowy road has been known.

[0003] In this system, when a wheel slip exceeding a predetermined value is detected during braking of a vehicle, it is determined that there is a possibility of wheel lock, and the braking force applied to the wheels is adjusted to perform high deceleration according to the road surface condition. This is to start the braking force control to be generated. Specifically, when the wheel speed starts dropping with respect to the vehicle speed during the braking operation by the driver, the ABS starts control and automatically reduces the braking force applied to the wheels to prevent the wheel speed from dropping. I do. After that, until the vehicle stops, the wheel speed does not drop under the current braking operation, or until the braking operation is stopped, the braking is performed so that the wheel speed falls within a predetermined range with respect to the vehicle speed. Performs adjustment control to automatically increase or decrease the force.

[0004]

However, if the ABS control is repeated to increase or decrease the braking force, the deceleration of the vehicle in the front-rear direction may fluctuate. Vibrates, and the running feeling during braking is reduced.

[0005] If the driver wants to apply sudden braking, it is necessary to stop the vehicle at a short distance, and therefore, it is necessary to control the ABS so as to cause a high deceleration without causing an excessive slip. However, if the same control as in the case of the sudden braking is performed by the ABS until the driver desires the gentle braking (also called the gentle braking), the driver performs the braking operation with the intention of the gentle braking. Once the vehicle enters the ABS, the same braking force adjustment control as in the case of sudden braking is started, and the adjustment for increasing or decreasing the braking force is repeated frequently, resulting in deceleration that the driver does not plan, and The vehicle vibrated and the running feeling during slow braking was reduced.

Also, when the braking force is transmitted by various mechanisms for controlling the braking force by the ABS, in particular, when the braking fluid is transmitted by a brake fluid, a solenoid for switching the pipeline when the level of the braking force is adjusted. Switching sound,
The driving noise of the pump device for pumping the discharged brake fluid and the like became noise in the vehicle, which sometimes caused discomfort to the occupants.

An object of the present invention is to prevent the above-mentioned decrease in running feeling during braking by controlling the ABS differently in the case of gentle braking than in the case of sudden braking. It is assumed that. Another object of the present invention is to solve a noise problem.

[0008]

According to the vehicle braking control apparatus of the present invention, first, the slow braking determining means determines whether or not the driver is performing a slow braking operation by a braking operation detecting means. Is determined based on The braking force adjustment stopping means stops the adjustment of the braking force and reduces the constant braking force when the slow braking determining means determines that the driver is performing the slow braking operation during the braking force control. maintain.

In the case of a gentle braking operation, the degree of the braking force generated by the gentle braking operation does not greatly differ from the degree of the braking force performed in the braking force control. Therefore, even if it is determined that the wheel is likely to be locked based on the slow braking operation and the braking force control is started, or if the braking force control enters the slow braking operation state,
As long as the slow braking operation state is maintained, if the braking force generated during the slow braking operation or a braking force in the vicinity thereof is maintained, the braking is close to the degree desired by the driver. Therefore, the traveling feeling is improved.

[0010] Further, since the maintenance of the braking force is realized by not adjusting the braking force, the braking force does not cause an oscillating fluctuation to vibrate the vehicle.
Comfortable running is possible even during braking. At this time, since various mechanisms for adjusting the braking force are not driven, noise generated at the time of driving can be prevented, and further traveling comfort can be realized.

The adjustment of the braking force by the braking force adjustment stopping means is adjusted to be lower than the braking force when the driver determines that the driver is performing a gentle braking operation by the gentle braking determining means. When the stop start brake force is reached, the adjustment stop start brake force may be maintained. In this case, the maintained braking force is smaller than that during the gentle braking operation, so that a slight change in the road surface condition makes it difficult for the slip to become excessive, and is further safer, and the braking force is close to the braking state desired by the driver. Becomes

Since the process performed first when the wheel slips is a process of reducing the braking force applied to the wheel, the braking force may be maintained at the timing when the braking force is reduced to the adjustment stop start brake force at the time of this reduction. Good, but once the braking force decreases, it is increased again. Therefore, the braking force when the driver determines that the driver is performing a gentle braking operation is determined by this braking force increasing process. When the adjustment stop start brake force is set to be lower than the adjustment stop start brake force, the adjustment stop start brake force may be maintained.

In order to resume the adjustment of the braking force by the braking force control, for example, when the adjustment of the braking force is stopped by the braking force adjustment stopping means by the braking force adjustment resuming means, the braking force is controlled by a predetermined amount or more by the braking force control. When the wheel slip is detected, that is, when it is determined that the braking force should be adjusted in a lower direction, the adjustment of the braking force is restarted.

At first, even if the braking force is maintained in an appropriate range by the braking force adjustment stopping means, there is a possibility that excessive slip may occur if the road surface condition changes, Even when the force adjustment is stopped, if a wheel slip equal to or more than a predetermined value is detected by the brake force control based on the slip state or the like, the brake force adjustment is restarted so that excessive slip does not occur. To

Further, the braking operation amount storage means stores the braking operation amount of the driver detected by the braking operation detecting means when the braking force adjustment is stopped by the braking force adjustment stopping means, and the second braking operation is performed. In the force adjustment resuming unit, when the brake force adjustment is stopped by the brake force adjustment stop unit and the wheel force equal to or greater than a predetermined value is not detected by the brake force control, that is, when the brake force is to be adjusted in a lower direction. If it is determined that there is no braking operation, the braking force is adjusted when the braking operation detected by the braking operation detecting means is larger than the braking operation amount stored in the braking operation amount storage means by a predetermined amount or more. May be restarted.

That is, if the current braking operation amount is larger than the driver's braking operation amount at the time of stopping the adjustment of the braking force by more than a predetermined amount, the driver intends to further increase the braking force. In a situation where wheel slip of a predetermined level or more has not been detected, it is easier to follow the driver's will if it is left to braking force control by braking force control than to maintaining the braking force. It is.

In the brake force control ending means, if the wheel force equal to or greater than a predetermined value is not detected by the brake force control when the brake force adjustment is stopped by the brake force adjustment stop means, the braking operation is detected by the brake operation detecting means. The braking force control may be terminated when the braking operation to be performed is smaller than the braking operation amount stored in the braking operation amount storage means by a predetermined amount or more.

That is, if the current braking operation amount is smaller than the driver's braking operation amount at the time of stopping the adjustment of the braking force by a predetermined amount or more, the driver tries to further reduce the braking force from the gentle braking state. Can be determined. This indicates that the driver no longer performs a braking operation that would cause an excessive slip, and therefore, in a situation where a wheel slip exceeding a predetermined level is not detected, it is preferable to terminate the braking force control itself. However, this is because it is considered to be more in line with the driver's intention.

In the braking force control, usually, the braking force applied to the wheels is increased or decreased to adjust the wheels so as to maintain the wheels in a predetermined slip state. The determination as to whether or not the gentle braking operation is being performed can be made based on the road surface condition and the detection result of the braking operation detecting means.

It is preferable that the road surface condition and the detection result of the braking operation detecting means be determined by using a result obtained when the braking force applied to the wheel is reduced by the braking force control. As described above, when the braking operation of the driver is started by the braking operation of the driver and the braking operation of the driver is detected at the timing when the braking force is reduced, the degree of the braking of the rapid braking or the gentle braking appears in the operation. Therefore, it is easy to determine whether the braking is gentle.

Since the range of the gentle braking operation amount changes according to the road surface condition, the gentle braking determination means prepares data of the gentle braking operation amount range set in advance according to the road surface condition,
If this range includes the driver's braking operation detected by the braking operation detecting means, it may be determined that the driver is performing a gentle braking operation, and more accurate determination is possible. Become.

Here, the road surface condition is, specifically,
The friction state between the road surface and the wheels, for example, the coefficient of friction of the road surface with respect to the wheels is given. In addition, the value of the deceleration detected from the deceleration sensor of the vehicle may be used as the road surface condition. Further, the braking operation detecting means may detect an operation state of the brake pedal as a braking operation.

The operation state of the brake pedal may be detected as a depression stroke of the brake pedal detected by a stroke sensor, may be detected as a depression force of the brake pedal detected by a depression force sensor, and may be detected by a master pressure sensor. May be detected as the pressure of the master cylinder that generates the brake fluid pressure by operating the brake pedal.

Further, the following configuration may be added to further prevent noise. In other words, in the brake force control, if a pump device for recirculating the brake fluid discharged from the wheel side when reducing the brake force is provided, the brake force adjustment stopping means stops the adjustment of the brake force. When the brake force adjustment is stopped by the brake force adjustment stopping means or the braking force control is not performed on all other wheels, the driving of the pump device is performed by the pump stopping means. May be stopped. This eliminates a noise source in the pump device, for example, noise generated by rotation of the motor, and has a further noise prevention effect.

The function of realizing each means of such a vehicle braking control device by a computer system is provided, for example, as a program activated on the computer system side. In the case of such a program, for example,
Floppy disk, magneto-optical disk, CD-ROM,
It can be used by storing it in a machine-readable storage medium such as a hard disk, loading it into a computer system as needed, and starting it. In addition, ROM
Alternatively, the program may be stored as a machine readable storage medium such as a ROM or a backup RAM, and the ROM or the backup RAM may be incorporated in a computer system and used.

[0026]

FIG. 1 is a block diagram showing a schematic configuration of a vehicle braking control device to which the above-mentioned invention is applied. Each wheel of the vehicle (left front wheel FL, right front wheel FR, left rear wheel R
L, right rear wheel RR), a hydraulic brake device (hereinafter referred to as a wheel cylinder: W / C) 2FL, 2FR, 2RL, 2R for applying a braking force to each of the wheels FL to RR.
R and wheel speed sensors 4FL, 4FR, 4RL, 4RR for detecting the rotational speeds of the wheels FL to RR are provided respectively.

On the other hand, the torque output from the engine (here, an internal combustion engine) 6 via the transmission 8 is
It is distributed to each of the left and right front wheels FL, FR. Further, the vehicle body (not shown) has a G sensor 14 having both functions of a longitudinal acceleration sensor in the front-rear direction and a lateral acceleration sensor in the left-right direction, a stop switch 36 which is turned on when the brake pedal 32 is operated, and a brake. A master cylinder pressure sensor 38 for detecting a brake oil pressure of a master cylinder (hereinafter, also referred to as M / C) 34 that discharges brake oil when the pedal 32 is depressed is also provided. Detection signals from the G sensor 14, the stop switch 36, and the master cylinder pressure sensor 38, as well as detection signals from the wheel speed sensors 4FL to 4RR, etc., are input to an electronic control unit (hereinafter referred to as ECU) 20. .

The ECU 20 controls various actuators in a hydraulic circuit 40 provided in a hydraulic path from the master cylinder 34 to the wheel cylinders 2FL to 2RR of the wheels FL to RR based on these detection signals. ABS control (corresponding to the above-described braking force control) for suppressing slip generated on the wheels FL to RR during vehicle braking, and each wheel FL performed in the ABS control
.About.RR, slow braking control described later is executed.

The ECU 20 has a CPU, ROM, RA
It is mainly configured by a microcomputer including M and the like. In addition, each process executed by the ECU 20 such as ABS control and gentle braking control, which will be described later, is stored in the ROM as a program, and is executed as necessary.

Next, the hydraulic circuit 40 will be described. As shown in FIG. 2, the hydraulic circuit 40 supplies the brake oil pumped from the two oil passages of the M / C 34 to the left front wheel FL and the right rear wheel RR, and the right front wheel FR and the left rear wheel RL, respectively. The two hydraulic paths 42 and 44 are provided. this is,
In the case of the X pipe of the front engine front drive (FF) system, the front engine rear drive (F
R) In the case of front and rear piping, the right front wheel FR and the left front wheel FL,
There are two hydraulic paths for supplying to the right rear wheel RR and the left rear wheel RL. Hereinafter, the case of the X pipe of the FF system will be described.

In the hydraulic path 42, a path 42FL reaching the wheel cylinder 2FL of the left front wheel FL and a right rear wheel RR
And the route 42RR to the wheel cylinder 2RR of
Electromagnetic pressure increase control valves 46FL, 46RR that can be switched between a pressure increase position communicating the paths 42FL, 42RR and a holding position that shuts off the paths, and the brake oil in each wheel cylinder 2FL, 2RR is discharged. And a pressure reducing valve 48FL, 48RR of the electromagnetic type for controlling the pressure.

Similarly, in the hydraulic path 44, a path 44FR reaching the wheel cylinder 2FR of the right front wheel FR
And the route 4 leading to the wheel cylinder 2RL of the left rear wheel RL
4RL includes the routes 44FR and 44RL, respectively.
Pressure-increasing control valves 46FR and 46RL that can be switched between a pressure-increasing position that communicates with a pressure-retaining position and a holding position that shuts off the path.
Electromagnetic decompression control valves 48FR and 48RL for discharging brake oil from the wheel cylinders 2FR and 2RL are provided.

The pressure increase control valves 46FL, 46FR, 46
RL and 46RR are usually at the pressure increasing position, and EC
The position is switched to the holding position by energization from U20. Further, the pressure reducing control valves 48FL, 48FR, 48RL, 48R
R is normally in a shut-off state, becomes in a communicating state by being energized from the ECU 20, and discharges brake oil in the corresponding wheel cylinders 2FL to 2RR.

On the other hand, in the hydraulic path 42, a master cylinder cut valve (hereinafter, referred to as an SM valve) 50a is provided on a path on the M / C 34 side of the pressure increase control valves 46FL and 46RR to connect and cut off the path. ing. Then, in parallel with the SM valve 50a, when the oil pressure on the M / C 34 side becomes larger than the oil pressure on the pressure increase control valves 46FL, 46RR, the oil pressure is output from the M / C 34 to the pressure increase control. Relief valve 5 for supplying to valves 46FL and 46RR
4a is connected.

Similarly, in the hydraulic path 44, an SM valve 50b is also provided on a path on the M / C 34 side of the pressure increase control valves 46FR and 46RL to connect / disconnect the path. Then, in parallel with the SM valve 50b, M / C3
The relief valve 54b which communicates when the hydraulic pressure on the fourth side becomes higher than the hydraulic pressure on the pressure increase control valves 46FR, 46RL and supplies the pressure oil output from the M / C 34 to the pressure increase control valves 46FR, 46RL is provided. It is connected.

The SM valves 50a and 50b are powered off.
Sometimes the communication state is established, and the state is switched to the cut-off state by energization from the ECU 20. SM valve 50a, 50b
Are connected in parallel with differential pressure valves PRVa and PRVb, respectively.
The flow of brake oil from the wheel cylinder side to the wheel cylinder side is prohibited, and the flow of brake oil from the wheel cylinder side to the M / C
Allowed when the pressure on the / C34 side becomes higher than a predetermined pressure. The predetermined pressure may be set at 50 atm to 200 atm, and each differential pressure valve PRVa, PRVb
At the time of discharge of 0 and 62, the pipeline is protected so that the pressure in the pipeline closer to the wheel cylinder than the SM valves 50a and 50b does not exceed a predetermined pressure.

In FIG. 2, the SM valves 50a and 50b are provided with parallel pipes, and the differential pressure valves PRVa and PRVb are provided in these pipes.
, But instead of such a configuration,
Even when a configuration is adopted in which the valve elements at the shut-off positions of the SM valves 50a and 50b are differential pressure valves having a predetermined relief pressure (opening pressure), and the differential pressure valves PRVa and PRVb are built in each of the SM valves 50a and 50b. Good.

Further, in each of the hydraulic paths 42 and 44,
Reservoirs 56 and 58 for temporarily storing the brake oil discharged from the pressure reducing control valves 48FL to 48RR are provided, and the brake oil is further supplied to the SM valve 50a and the pressure increasing control valve 46F.
Pumps 60 and 62 are provided for pumping pressure to the path between L and 46RR and the path between the SM valve 50b and the pressure increase control valves 46FR and 46RL, respectively. In addition, each pump 6
Accumulators 64 and 66 for suppressing the pulsation of the internal hydraulic pressure are provided in the brake oil discharge path from 0 and 62, respectively.

Each hydraulic path 42, 44 has an M / C
Reservoir 34 provided above M / C 34 via
8 are provided with oil supply paths 42P, 44P for supplying brake oil directly to the pumps 60, 62. These oil supply paths 42P, 44P communicate with the oil supply paths 42P, 44P.
Reservoir cut valve to shut off (hereinafter referred to as SR valve)
70a and 70b are provided respectively.

Incidentally, the SR valves 70a and 70b are normally in a shut-off state, and are switched to a communication state by energization from the ECU 20. Also, each pump 60, 62
It is driven via the motor 80 when performing BS control or the like. Next, the ABS control and the gentle braking control performed by the ECU 20 will be described.

When the ABS control and the gentle braking control are not performed, the pressure increasing mode shown in FIG. 7 is set, and all the solenoid valves of the hydraulic circuit 40 are turned off (OFF). FIG.
This shows the non-control state. Specifically, the SM valve 50
a, 50b = communication position and SR valves 70a, 70b =
It is a shut-off position, and furthermore, the pressure increase control valves 46FL-46RR
= Communication position, pressure reduction control valves 48FL-48RR = Shutoff position.

ABS control For example, each wheel FL ~
When a slip occurs in the RR, as shown in FIG. 3, the ABS control is started for each of the wheels FL to RR, and the SM valves 50a, 5
0b = communication position (OFF) and SR valves 70a, 70b =
With the shut-off position (OFF), the motor 80 is driven to operate the pumps 60 and 62, and further, the pressure increase control valve 46FL
7 to 46RR and the pressure reduction control valves 48FL to 48RR are turned ON / OFF (energized / deenergized), respectively, so that the brake hydraulic pressure in each of the wheel cylinders 2FL to 2RR in accordance with the slip state of each wheel FL to RR is shown in FIG. Are appropriately switched to two states, ie, a pressure reduction mode and a pulse pressure increase mode.

More specifically, if it is determined that the wheels are in a locking tendency, that is, it is falling from the deceleration of the wheels to an excessive slip state, the pressure reducing mode is executed, and the pressure increasing control valve 46FL corresponding to the wheel is executed. To block 46RR (O
N) and repeating the communication (ON) and shutoff (OFF) of the pressure reduction control valves 48FL to 48RR to reduce the oil pressure of the corresponding wheel cylinders 2FL to 2RR, thereby preventing the wheels from being locked. At this time, the amount of oil depressurized from the wheel cylinders 2FL to 2RR is reduced by the depressurization control valve 48.
FL-48RR are discharged to the reservoirs 56 and 58, and further driven by the motor 80, the reservoir 5
The brake oil accumulated in 6,58 is returned to the normal brake system.

When it is determined that the locking tendency of the wheel has been eliminated during the ABS control, the pulse pressure increasing mode is executed, and the pressure increasing control valves 46FL to 46RR corresponding to the wheel are executed.
Is repeated (OFF) and shut off (OFF), and the pressure reduction control valves 48FL to 48RR are shut off (OFF) to increase the hydraulic pressure of the corresponding wheel cylinders 2FL to 2RR.

In the ABS control, by such control,
The stability of the vehicle is ensured while preventing the wheels from being locked by repeating the pressure reduction mode and the pulse pressure increase mode of the W / C hydraulic pressure. If the brake pedal 32 is not depressed from the state of the stop switch 36 and the wheels do not tend to lock even if the pressure is sufficiently increased in the pulse pressure increasing mode, the ABS control is stopped and FIG. In other words, when the driver increases the wheel cylinders 2FL to 2RR
Return to the state where the hydraulic pressure of can be adjusted.

Slow braking control Next, the processing when the driver performs a gentle braking operation (slow braking) will be described with reference to the flowchart of the slow braking control start determination processing in FIG. 4 and the slow braking control end determination processing in FIG. Will be explained. These processes are performed for each wheel, and are repeatedly executed.

First, in the slow braking control start determination processing of FIG. 4, it is determined whether or not the ABS control is being performed (S110).
If the ABS control is not being performed ("NO" in S110), the process ends as it is. If ABS control is being performed (S110
Is "YES"), and it is determined whether or not the apparatus is in the pulse pressure increasing mode (S120). As described above, in the ABS control, the W / C oil pressure is reduced by the pressure reduction mode and the W / C oil pressure is increased by the pulse pressure increase mode, so that the W / C oil pressure is increased.
Since the C hydraulic pressure has been adjusted, it is determined in the ABS control whether or not it is determined that the pulse pressure increasing mode should be set.

If not in the pulse pressure increasing mode (S12)
0 and “NO”), the processing in the normal ABS control described above is continued (S130). If it is the timing of the pulse pressure increase mode state ("YES" in S120), then
It is determined whether or not the hydraulic pressure stop mode is already set (S14).
0).

The hydraulic pressure stop mode is a special mode which is set separately from the setting of the pressure reduction mode or the pulse pressure increase mode and is performed at the time of gentle braking in the ABS control. As shown in FIG. Shut off both control valves 46FL-46RR and pressure-reducing control valves 48FL-48RR (pressure-increasing control valve 46 = O
N, the pressure reduction control valve 48 is turned off) to maintain the W / C hydraulic pressure.

If it is not the hydraulic pressure stop mode (S140)
Then, it is determined whether the master cylinder pressure (M / C pressure) detected by the master cylinder pressure sensor 38 is included in the control region shown in FIG. 6 (S150). FIG. 6 shows the road surface μ (the coefficient of friction of the road surface with respect to the wheels) as the value of the vehicle deceleration obtained from the G sensor 14, and indicates in which range the master cylinder pressure is in relation to the vehicle deceleration. The hatched portion shown in the figure corresponds to the control area. If the control area includes the relationship between the road surface μ and the master cylinder pressure, it is determined that the braking operation of the driver is gentle braking.

In a region U where the master cylinder pressure is higher than this region, it is determined that the driver's braking operation is sudden braking. Further, a region D in which the master cylinder pressure is lower than this region is excluded because it is a region that cannot normally be achieved by the ABS control. Note that the broken line represents the average master cylinder pressure performed as gentle braking.

If it is not within this control area (S1
("NO" at 50), the processing in the normal ABS control described above is continued (S130). If it is within the control area ("YES" in S150), then the wheel acceleration DV
It is determined whether W is less than 0 G, that is, whether or not the vehicle is in a deceleration state (S160). In the case of slow braking, DVW <
0G, but if DVW <0G (S
(“NO” in 160), the process proceeds to the normal ABS control in step S130 as failsafe.

If DVW <0G ("YE" in S160)
S "), and then in the execution of the current pulse intensification mode,
It is determined whether three to seven pulses for pressure increase have already been output (S170). This is because the pulse pressure increase mode is not executed, or the W / C
When the increase in the oil pressure stops, the actual W / C oil pressure is maintained at a considerably lower value from the W / C oil pressure requested by the driver due to gentle braking, and does not conform to the driver's feeling. This is because with 9 pulses, the W / C oil pressure rises excessively and the possibility of falling into a wheel locked state due to a slight change in the road surface or the like considerably increases.

Therefore, if the number of pulses is not 3 to 7 ("NO" in S170), the flow shifts to normal ABS control in step S130. If the number of pulses is 3 to 7 ("YES" in S170), the hydraulic pressure stop mode is set, the process of continuously maintaining the W / C hydraulic pressure is performed, and the master cylinder pressure at this time is reduced. ECU as master cylinder pressure PMCINT at start of hydraulic stop mode
20 (S180).

Next, after the processing of step S180, or after "YES" is determined in step S140, whether the hydraulic stop mode has already been set in the same control for all the other wheels, or It is determined whether or not the pressure increasing mode is set (that is, the state where the ABS control is not performed) (S190). This is for determining whether or not the motor 80 can be stopped, and all other wheels are in the hydraulic stop mode or A
If the BS control is not performed (pressure increase mode), all the W / C hydraulic pressures are held or the M / C 34
, The brake oil is not directly discharged to the reservoirs 56 and 58,
This is because there is no need to rotate the motor 80 for driving the pumps 60 and 62.

If there is no other wheel, neither the hydraulic pressure stop mode nor the pressure increase mode (S190: "N
O "), the process ends as it is. If all the other wheels are in the hydraulic pressure stop mode or the pressure increase mode ("YES" in S190), it is next determined whether or not the ON state of motor 80 has continued for a predetermined time kt or longer (kt). S2
00). This is because if the motor 80 is stopped by driving only for a predetermined time kt or less, the relay that performs on / off switching of the motor 80 is welded.
This is to prevent the failure of the relay. During this time, the brake oil also serves to discharge the brake oil accumulated in the reservoirs 56 and 58.

If the ON state of the motor 80 has not exceeded the predetermined time kt ("NO" in S200), the process is terminated as it is. The ON state of the motor 80 is maintained for a predetermined time kt.
Is exceeded (“YES” in S200), the motor 80
Is stopped (S210). By stopping the motor 80, generation of noise in the motor 80 and the pumps 60 and 62 is avoided.

Next, a description will be given of the slow braking control end determination processing of FIG. This process is performed as a process inside the ABS control. First, it is determined whether or not the mode is the hydraulic pressure stop mode (S310). If not in hydraulic stop mode (S
310 ("NO"), the normal ABS control processing (S32)
0) is performed.

In the hydraulic stop mode ("Y" in S310)
ES "), and a mode determination process for determining whether to set the pressure reduction mode or the pulse pressure increase mode in the ABS control shown in FIG. 7 from the wheel slip state separately performed in the ABS control. (S330), and when it is determined that the pressure should be reduced, that is, when an excessive slip is about to occur and it is determined that the W / C oil pressure needs to be reduced. ("YES" in S330), immediately returns to the normal ABS control to prevent the excessive slip state (S330).
320).

If the mode is not the pressure reducing mode, that is, if the mode is the pulse pressure increasing mode ("NO" in S330),
Next, the current master cylinder pressure PMC detected by the master cylinder pressure sensor 38 is determined in step S180.
Master cylinder pressure P at start of hydraulic stop mode stored in
It is determined whether the value of MCINT is in the relationship of the following equation 1 (S340).

[0061]

(Equation 1)

Here, k1 is an offset value (> 0) set according to the road surface friction coefficient. If the relationship of Expression 1 is satisfied ("YES" in S340), it can be determined that the driver has further depressed the brake pedal 32. Thus, the state immediately before the hydraulic stop mode is ended and the hydraulic stop mode is started. The normal ABS control is continued from (S3
70). However, if PMC <PMCINT, then PMCINT1 =
Re-stored as PMC, and replace Equation 1 with "PMC> PMCI
NT1 + k1 ”.

When the relationship of the above equation 1 is not satisfied (S3
("NO" at 40), it is determined whether or not the current master cylinder pressure PMC has the relationship of the following equation 2 with respect to the value of PMCINT (S350).

[0064]

(Equation 2)

Here, k2 is an offset value (> 0) set according to the road surface friction coefficient. If the relationship of the above expression 2 is satisfied ("YES" in S350), it can be determined that the driver has returned the brake pedal 32, that is, has released the brake pedal 32 further, and the brake pedal 32 has been released even in such a depressurization mode. If so, it is considered that the ABS control is unnecessary, and the process returns to the pressure increasing mode (S360). That is, the ABS control itself is ended. As a result, the state returns to a state where the driver can directly adjust the W / C hydraulic pressure.

If the relationship of the above expression 2 is not satisfied ("NO" in S350), the hydraulic pressure stop mode is continued. As a result, in the hydraulic pressure stop mode in which the control is started in the middle of the pulse pressure increasing mode, a braking force suitable for the driver's request can be generated unless excessive slip occurs.

FIG. 8 is a timing chart in the case where the slow braking process is performed in the configuration of the present embodiment. When the driver depresses the brake pedal 32, the W / C
When the hydraulic pressure rises and the wheels FL, FR, RL, RR are braked to a certain degree or more, the wheel speed starts to fall apart from the vehicle speed. As a result, it is determined that the vehicle is heading for excessive slip and the ABS control is started (at time t).
0). Then, when the pressure reduction mode is entered by the ABS control (time t1), it is determined that the braking is moderate if the vehicle is in the control area by referring to the master cylinder pressure at this time and the map of FIG.

Thereafter, the mode is shifted from the pressure reduction mode by the ABS control to the pulse pressure increase mode (time t2), and the number of pulses is 3 to 7
Master cylinder pressure PMC at the start of hydraulic stop mode
The value of INT is stored and the hydraulic pressure stop mode is entered to stop the normal W / C hydraulic pressure adjustment by the ABS control (time t3).

Next, from time t4, when the driver returns the brake pedal 32, the master cylinder pressure PMC
Satisfies the relationship of the above expression 2 (time t5), the ABS control itself is stopped and the pressure increase mode is set, and the W / C oil pressure is adjusted by the master cylinder pressure PMC.

On the other hand, when the driver further depresses the brake pedal 32 from time t4, as shown by the broken line,
When the master cylinder pressure PMC rises and the master cylinder pressure PMC satisfies the relationship of the above equation (time t6),
Returning to the normal ABS control again, the pulse pressure increase mode is continued, and the W / C oil pressure is increased as indicated by the broken line unless there is a possibility that an excessive slip may occur. As described above, according to the present embodiment, the normal ABS control is performed at the time of sudden braking, whereas the hydraulic stop mode is executed during moderate braking to adjust the hydraulic pressure with an appropriate W / C hydraulic pressure. Stop W /
C hydraulic pressure is maintained. Therefore, at the time of gentle braking, the same control as that at the time of sudden braking is not performed, so that the driving feeling is improved, and the W / C hydraulic pressure does not cause an oscillating change, so that the change in braking force is caused. The vehicle does not vibrate back and forth, and does not cause discomfort during braking. At the same time, since various mechanisms of the hydraulic circuit 40 such as a solenoid for adjusting the W / C oil pressure are not driven, the hydraulic circuit 40 is not driven.
Can also be prevented from occurring when the device is driven.

When the other wheels are in the hydraulic stop mode or the ABS control is not performed, the motor 80 is stopped, and the motor 80 and the pumps 60 and 62 emit the motor. Noise is eliminated, the noise prevention effect is high, and the comfort during driving can be improved.

In the present embodiment, the master cylinder pressure sensor 38 corresponds to the braking operation detecting means, and
150 corresponds to processing as slow braking determination means, steps S170 and S180 correspond to processing as braking force adjustment stopping means, and W / C achieved in step S170 in the range of 3 to 7 pulses. The hydraulic pressure corresponds to the adjustment stop start brake force, and steps S330, S320
Corresponds to processing as braking force adjustment restarting means, step S180 corresponds to processing as braking operation amount storage means, steps S340 and S370 correspond to processing as second braking force adjustment restarting means, and steps S350 and S370. S
360 corresponds to the processing as the braking force control ending means, the G sensor 14 corresponds to the deceleration sensor, and the pump 6
0 and 62 and the motor 80 correspond to the pump device, and steps S190 and S210 correspond to the processing as the pump stopping means.

[Others] In the above embodiment, the braking operation of the driver is detected by the master cylinder pressure sensor 38 as the braking operation detecting means. Equipped with a stroke sensor that detects the depression stroke,
The operation state of the brake pedal 32 may be detected from a depression stroke detected by a stroke sensor.

Further, instead of the stroke sensor, a stepping force sensor for detecting the stepping force of the brake pedal 32 may be provided, and the operation state of the brake pedal 32 may be detected from the stepping force detected by the stepping force sensor.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of an entire braking control system of an automobile as an embodiment.

FIG. 2 is an explanatory diagram of a configuration of a hydraulic circuit of a braking control system as one embodiment.

FIG. 3 is a timing chart illustrating ABS control performed by an ECU as one embodiment.

FIG. 4 is a flowchart of a slow braking control start determination process executed by an ECU as one embodiment.

FIG. 5 is a flowchart of slow braking control end determination processing executed by an ECU as one embodiment.

FIG. 6 is an explanatory diagram of a map of a control area.

FIG. 7 is an explanatory diagram of each control mode of braking.

FIG. 8 is a timing chart illustrating an example of a process.

[Explanation of symbols]

FL: Left front wheel FR: Right front wheel RL: Left rear wheel RR: Right rear wheel 2FL, 2FR, 2RL, 2RR: Wheel cylinder (W / C) 4FL, 4FR, 4RL, 4RR: Wheel speed sensor 14: G sensor 20 ... ECU 32 brake pedal 34 master cylinder (M / C) 36 stop switch (STP) 38 master cylinder pressure sensor 40 hydraulic circuit 42, 44 hydraulic path 46FL, 46FR, 46RL, 46RR pressure increase control valve 48FL , 48FR, 48RL, 48RR ... pressure reducing control valve 50a, 50b ... SM valve 54a, 54b ... relief valve 56, 58 ... reservoir 60, 62 ... pump 64, 66 ... accumulator 70a, 70b ... SR
Valve 80: Motor

Claims (17)

[Claims] 1. A braking force control that starts when a wheel slip of a predetermined value or more is detected during braking of a vehicle and that adjusts a braking force applied to wheels to cause a high deceleration of the vehicle in accordance with a road surface condition. A braking operation detecting means for detecting a braking operation of the driver; and a braking control device for determining whether or not the driver is performing a gentle braking operation based on a detection result of the braking operation detecting means. Braking judgment means, during the braking force control, when the slow braking judgment means determines that the driver is performing a gentle braking operation, stops adjusting the braking force to reduce the constant braking force. And a braking force adjustment stopping means for maintaining the braking force. 2. The braking force adjustment stop when the driver determines that the driver is performing a gentle braking operation by the slow braking determination means by the braking force adjustment stopping means is performed by the slow braking determination means. When the adjustment stop start brake force is set lower than the brake force when it is determined that the user is performing a gentle braking operation, the adjustment stop start brake force is maintained. The vehicle braking control device according to claim 1, wherein 3. The braking force adjustment stop when the driver determines that the driver is performing a gentle braking operation by the slow braking determination means by the braking force adjustment stopping means is performed after the execution of the braking force reduction process. When the braking force is increased, the adjustment stop start braking force is set to be lower than the braking force when the driver determines that the driver is performing a gentle braking operation by the gentle braking determining means. 3. The vehicle brake control device according to claim 2, wherein the control is performed by maintaining the adjustment stop start brake force. 4. A braking force adjustment resuming means for resuming the adjustment of the braking force when a predetermined or more wheel slip is detected by the braking force control when the braking force adjustment is stopped by the braking force adjustment stopping means. The vehicle braking control device according to any one of claims 1 to 3, further comprising: 5. A braking operation amount storing means for storing a driver's braking operation amount detected by the braking operation detecting means when the braking force adjustment is stopped by the braking force adjustment stopping means; When a wheel slip equal to or more than a predetermined value is not detected by the brake force control when the adjustment of the brake force is stopped by the adjustment stop unit, the braking operation detected by the braking operation detection unit is stored in the braking operation amount storage unit. And a second braking force adjustment resuming means for resuming the adjustment of the braking force when the braking operation amount becomes larger by a predetermined amount than the stored braking operation amount.
The vehicle braking control device according to any one of the above. 6. A braking operation amount storage means for storing a driver's braking operation amount detected by the braking operation detection means when the braking force adjustment is stopped by the braking force adjustment stopping means; When a wheel slip equal to or more than a predetermined value is not detected by the brake force control when the adjustment of the brake force is stopped by the adjustment stop unit, the braking operation detected by the braking operation detection unit is stored in the braking operation amount storage unit. 5. A vehicle braking system according to claim 1, further comprising a braking force control ending means for terminating said braking force control when the braking operation amount becomes smaller than a predetermined braking operation amount by a predetermined amount. Control device. 7. A brake detected by the braking operation detecting means when a wheel slip equal to or more than a predetermined value is not detected by the braking force control when the braking force adjustment is stopped by the braking force adjustment stopping means. A braking force control ending means for terminating the braking force control when the operation is smaller than a braking operation amount stored in the braking operation amount storage means by a predetermined amount or more. The vehicle braking control device according to claim 5. 8. The braking force control according to claim 1, wherein the braking force applied to the wheels is increased or decreased so as to adjust the wheels so as to maintain a predetermined slip state. And determining whether the driver is performing a gentle braking operation based on a detection result of the braking operation detecting means.
8. The vehicle braking control device according to any one of items 7 to 7. 9. The slow braking determining means, based on a road surface condition and a detection result of the braking operation detecting means, obtained when the braking force applied to the wheels is reduced by the braking force control. The vehicle braking control device according to claim 8, wherein it is determined whether the vehicle is performing a gentle braking operation. 10. The braking control device according to claim 1, wherein the braking operation of the driver detected by the braking operation detecting device is included in a range of a gentle braking operation amount set in advance according to a road surface condition. 10. The vehicle braking control device according to claim 1, wherein it is determined that the driver is performing a gentle braking operation. 11. The vehicle braking control device according to claim 1, wherein the road surface condition is a friction state between the road surface and wheels. 12. A vehicle according to claim 11, further comprising a deceleration sensor for detecting a deceleration of the vehicle, wherein a value of the deceleration of the vehicle detected by the deceleration sensor is used as the frictional state. The vehicle braking control device according to any one of the preceding claims. 13. The vehicle braking control device according to claim 1, wherein said braking operation detecting means detects a braking operation by detecting an operation state of a brake pedal. 14. A stroke sensor for detecting a depression stroke of the brake pedal, wherein an operation state of the brake pedal in the braking operation detection means is detected from a depression stroke detected by the stroke sensor. The vehicle braking control device according to claim 13. 15. A depressing force sensor for detecting a depressing force of the brake pedal, wherein an operation state of the brake pedal in the braking operation detecting means is detected from a depressing force detected by the depressing force sensor. The vehicle braking control device according to claim 13. 16. A master cylinder pressure sensor for detecting a pressure of a master cylinder which generates a brake fluid pressure by operating the brake pedal, wherein an operation state of the brake pedal in the braking operation detecting means is controlled by the master cylinder pressure sensor. The vehicle braking control device according to claim 13, wherein the detection is performed from the pressure detected by the vehicle braking. 17. A brake device, wherein the brake force is provided to a wheel side via a brake fluid, and further includes a pump device for recirculating brake fluid discharged from the wheel side when the brake force is reduced. In the case where the adjustment of the braking force is stopped by the adjustment stopping means and the stopping of the adjustment of the braking force is executed by the braking force adjustment stopping means for all the other wheels, or the braking force control is performed. 17. The vehicle braking control device according to claim 1, further comprising a pump stop unit that stops driving of the pump device when there is no pump.