JP3405765B2 - Brake control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device for a vehicle.

[0002]

2. Description of the Related Art A general automobile is provided with assisting means such as a booster (booster) for assisting a braking force generated by operating a brake operation inputting means such as a brake pedal.

By the way, since the kinetic energy of the vehicle is extremely large during traveling on a highway, for example, it is desired that the braking force with respect to the amount of depression of the brake pedal be large. That is, a characteristic is desired that a large braking force is generated even when the depression amount of the brake pedal is small.

On the other hand, when traveling in a traffic jam, low-speed acceleration / deceleration is frequently performed. Therefore, when a large braking force is generated despite the small depression amount of the brake pedal, a sudden deceleration is generated. It is easy to run. For this reason, in traffic congestion, if the amount of depression of the brake pedal is the same, it is desired that a smaller braking force be generated as compared with high speed traveling.

As described above, even if the amount of depression of the brake pedal is the same, it is preferable that the magnitude of the generated braking force be variously changed according to the running state of the vehicle.

Therefore, for example, Japanese Patent Laid-Open No. 1-266050.
In the vehicle brake control device disclosed in the publication, the braking force generated with respect to the depression amount of the brake pedal is changed based on the average vehicle speed and the vehicle speed fluctuation rate within a predetermined time.

[0007]

However, in the brake control device described in the above publication, the vehicle speed variation rate is used as one parameter for changing the braking force, and therefore the braking force is changed even when the vehicle speed variation rate changes due to acceleration. Therefore, it is not always possible to obtain the optimum braking characteristics according to the running state.

In addition, the change of the braking force (assist force)
There was a risk that the driver would feel uncomfortable.

In view of the above-mentioned circumstances, it is an object of the present invention to provide a brake control device capable of obtaining optimum brake characteristics according to a running state.

[0010]

As shown in FIG. 1, a brake control device according to the present invention includes assist means for assisting a braking force generated by operation of a brake operation input means such as a brake pedal, and the assist means. An assist force varying means capable of changing the assist force generated from
Brake operation for detecting the operation of the brake operation input means
A work detecting means, and calculating means for calculating the average vehicle speed and average deceleration of the vehicle within the predetermined time, the assist amount based on the average vehicle speed and average deceleration calculated by said calculating means,
At least with an increase in average deceleration, and
An assist amount determining means that determines to decrease as the average deceleration decreases, a control means that controls the assist force varying means based on the assist amount determined by the assist amount determining means, and the brake operation detecting means. Detected by
Based on the above, while the brake operation input means is being operated,
Restricting the change of assist force by the cyst force changing means
And a cyst force change restricting means .

[0011]

According to the above invention, the assist force is changed according to the average vehicle speed and the average deceleration of the vehicle within the predetermined time, so that the optimum braking characteristic according to the running state can be obtained. it can.

[0012] In addition, during the operation of the probe Rekipedaru because the change of the assist force is restricted, it is possible to change the assist force to avoid the possibility of giving an uncomfortable feeling to the driver.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an overall system diagram showing an embodiment of a brake control device according to the present invention.

In FIG. 2, 1 is a brake pedal, 2 is a master cylinder, and between the brake pedal 1 and the master cylinder 2, a main booster 3 and a sub-booster 4 connected in a tandem type are provided as assisting means. Has been done.

The main booster 3 is provided with a diaphragm 7 provided inside the shell 6 in a state of being urged to the left by the return spring 5, and a diaphragm chamber 8 partitioned by the diaphragm 7 is provided in the diaphragm chamber 8. The vacuum pressure in the intake manifold of the engine or the vacuum pressure from the vacuum pump is supplied through the check valve 9.

Similarly, the sub-booster 4 is provided with a diaphragm 12 provided in the shell 11 in a state of being urged to the left side in the drawing by a return spring 10, and the diaphragm 12 is partitioned by the diaphragm 12. An air chamber 14 is connected to the chamber 13.

A vacuum pressure is supplied to the air chamber 14 through a check valve 15 and a control valve (vacuum valve) 16, and an atmospheric pressure is supplied through a control valve 17 (atmospheric pressure valve). It has become. The control valves 16 and 17 are duty solenoid valves.
The opening degree of 7 is duty-controlled by a control unit 20 composed of a microcomputer, whereby the assisting force by the sub-booster 4 is changed as described later.

The brake pedal 1 and the piston 21 of the master cylinder 2 are connected by a rod 22 extending through the central portions of the diaphragms 7 and 12 of the main booster 3 and the sub-booster 4, and this rod 22 is also connected. The central portions of the diaphragms 7 and 12 are engaged with.

Therefore, when the diaphragm chambers 8 and 13 have a negative pressure, the central portions of the diaphragms 7 and 12 are displaced rightward in FIG. 2 against the urging forces of the return springs 7 and 10, respectively, whereby the brakes are braked. An assisting force with respect to the pedaling force of the pedal 1 is applied to the rod 22. Then, in this case, the pedaling force of the brake pedal 1 is applied to the piston 21 of the master cylinder 2 and the assisting force of the sub booster 4 is applied in a manner in which the assisting force of the main booster 3 and the assisting force of the sub booster 4 are combined. It is configured such that the variable assist force changes the entire assist force.

Reference numeral 25 is a hydraulic disc brake device,
The disk 27 that rotates with the wheels 26 and the caliper 2
8 and. The caliper 28 is a brake pad 29.
And a cylinder 30 is provided, and the brake pad 29 is pressed against the disc 27 by a force according to the magnitude of the brake fluid pressure supplied from the master cylinder 2 to the cylinder 30 through the oil passage 31.
Braking force is generated on the wheels 26.

The disc brake device 25 shown in the figure is for the front wheels, and the brake fluid pressure for the brake device for the rear wheels (not shown) is supplied from the oil passage 31 via the proportioning valve 32.

The control unit 20 includes a brake switch signal from a brake switch 41 for detecting depression of the brake pedal 1, a vehicle speed signal from a vehicle speed sensor 42 for detecting a vehicle speed, and a pressure in the air chamber 14. The chamber pressure signal from the pressure sensor 43 for detecting the
Outputs a control signal to the control valves 16 and 17.

Based on the vehicle speed signal from the vehicle speed sensor 42, the control unit 20 has a predetermined time (for example, 1
The average vehicle speed and the average deceleration for 0 minutes) are calculated, the boost ratio (assist amount) by the sub-booster 4 is determined from the average vehicle speed and the average deceleration, and the target in the air chamber 14 for obtaining this boost ratio. Set the pressure value,
From this target pressure value, the duty ratio of the control signal output to the control valves 16 and 17 is calculated, and the control valves 16 (vacuum valves) and 17 (so that the pressure value in the air chamber 14 approaches the target pressure value. Atmospheric pressure valve)
Control the duty. At the time of this control, feedback control using the output of the pressure sensor 43 is performed.

Next, the contents of the control routine executed by the control unit 20 will be described with reference to the flowcharts shown in FIG. In the following description, S indicates a step.

FIG. 3 shows a general flow. First, in S1, the entire system is initialized, then in S2, output signals from the brake switch 41, the vehicle speed sensor 42, and the pressure sensor 43 are read, and thereafter, in S3. The routines of calculating the average vehicle speed and the average deceleration within a predetermined time, determining the boost ratio in S4, and outputting the control signal in S5 are executed.

In the present embodiment, the average vehicle speed and the average deceleration for 10 minutes are calculated, and the boost ratio is determined based on the calculated average vehicle speed and the boost ratio. However, for the calculation of the average vehicle speed, the integrated data is calculated every one minute. Then, it is stored in the memory and the whole calculation is performed every minute. By adopting such an arithmetic method, since it is sufficient to have a memory capacity for storing 10 pieces of data, it is possible to improve the responsiveness by reducing the memory capacity and the arithmetic time.

The contents of the processing in S1 and S2 are shown in FIG.
In S2, the vehicle speed Vn, the brake switch signal Bsw, and the chamber pressure Pc are read.

The calculation routine of the average vehicle speed and the average deceleration in S3 is performed based on the flowcharts of FIGS. 5 and 6. That is, it is determined whether or not the deceleration flag is set to 1 in S11 of FIG. 5, and if the deceleration flag is 0 (S11, NO), the vehicle speed continuously decreases in three control cycles in S12. Check whether or not. When it is determined that the vehicle speed is decreasing three times in succession (S12, YES), the deceleration flag is set to 1 in S13, and the value VSPST of the vehicle speed Vn when deceleration is started in S14. Remember. Then, in S15, a timer measures the elapsed time from the time when the deceleration is started, and in S16, it is checked whether or not the vehicle speed has become constant or increased three times in a row, that is, whether or not the deceleration has ended. If the determination is YES, the deceleration G is obtained in S17. The deceleration G is obtained by dividing the value obtained by subtracting the vehicle speed VSPST at the start of deceleration from the current vehicle speed Vn by the elapsed time. Next, in S18, the deceleration flag F is reset to 0, the timer is reset, the deceleration end flag is set to 1, and the process proceeds to S19 of FIG.

On the other hand, when the deceleration flag is already 1 (S11, YES), the process proceeds from S11 to S15, and when the determination at S12 or S16 is NO, the process proceeds to S19.

Next, in S19 of FIG. 6, it is determined whether 10 minutes have elapsed. And until 10 minutes have passed (S1
(9, NO), S20 calculates the integrated value TV of the vehicle speed Vn for each control cycle. In the next S21, it is checked whether or not 1 minute has elapsed, and if 1 minute has elapsed (S21, YES), S22
The integrated value TV of the vehicle speed V for 1 minute is divided by the number of data for 1 minute to calculate the average vehicle speed AVV0 for 1 minute, and the integrated value TV is reset to 0 in S23.

In the next step S24, the average vehicle speed data for one minute is rotated. Then, in step S25, the sum of the 10 average vehicle speed data AVV1 to AVV10 is divided by 10 to obtain the average vehicle speed AVV for 10 minutes. . Then S26
Then, it is determined whether or not the deceleration end flag is set to 1. When the deceleration end flag is set to 1 (S26, YES), the integrated value TG of the deceleration G is calculated in S27, and The number of decelerations CG is counted and S28
The deceleration end flag is reset to 0. When the determination in S21 is NO, the process proceeds from S21 to S26.

On the other hand, when 10 minutes have elapsed and the determination result in S19 is YES, the integrated value TG of the deceleration G for 10 minutes is divided by the number of decelerations CG in S29 to obtain the average deceleration AVG for 10 minutes. Is calculated, and the integrated value TG and the number of decelerations CG are reset to 0 in S30. FIG. 7 shows the contents of the boost magnification determination routine in S4 of FIG.

In the memory of the control unit 20, as shown in S31, there is stored a map for obtaining the boost ratio K from the average vehicle speed AVV and the average deceleration AVG. The boost magnification K corresponding to the large, medium and small of the deceleration AVG is read from the map. As is clear from this map, the value of the boost ratio K is small when the average deceleration AVG is small, and the value of the boost ratio K is set to increase as the average deceleration AVG increases.

Next, in S32, the brake switch signal B
Whether or not sw is ON, that is, the brake pedal 1
If it is determined that the brake pedal 1 is not depressed (S32, NO), the boost magnification K read from the map is set to the final target magnification T in S33.
The boost magnification determination routine ends as GK, but when the brake pedal 1 is depressed (S32, YE
S) In order to prevent the driver from feeling uncomfortable, even if a request for changing the boost magnification is made, the change is prohibited and the change is allowed when the brake switch 41 is turned off.

In addition to the above, such regulation of boost magnification change, that is, regulation of assist force, may be continued until the brake switch 41 is turned on again. Further, instead of prohibiting the change of the boost ratio when the brake switch 41 is ON, the boost ratio may be gradually changed, or
The request for changing the boost magnification may be canceled.

Finally, the contents of the output process in S5 of FIG. 3 will be described based on the flowchart of FIG.

First, in S41, the final target magnification TGK is set.
From the map showing the relationship between the target chamber pressure TGP and
The target chamber pressure TGP corresponding to the final target magnification TGK is read.

Next, in S42, the actual chamber pressure Pc is subtracted from the target chamber pressure TGP to obtain the difference ΔP. Then, a dead zone having threshold values of positive and negative predetermined values α and -α is set, and ΔP> α, ΔP <-α, or -α <ΔP <α is set in S43 and S44. Is determined.

First, when it is determined at S43 that ΔP> α (S43, YES), the negative pressure in the vacuum chamber 14 is too high, so at S45, the control valve 16 (vacuum valve) is closed. It is determined that only the atmospheric pressure is introduced into the chamber 14, the duty ratio of the control signal for the control valve 17 (atmospheric pressure valve) corresponding to ΔP is read from the map in S46, and the control having this duty ratio is performed in S47. Signal control valve 17
(Atmospheric pressure valve) and control valve 16
For the (vacuum valve), set the duty ratio to 0.
Output the control signal as%.

On the other hand, when it is determined in S43 and S44 that ΔP <−α (S43, NO, S44, YE
S) Since the negative pressure in the vacuum chamber 14 is too low, it is determined in S48 that the control valve 17 (atmospheric pressure valve) is closed and only the vacuum pressure is introduced into the chamber 14, and in S49, according to ΔP. Control valve 16
The duty ratio of the control signal for the (vacuum valve) is read from the map, and in S47, the control signal having this duty ratio is output to the control valve 16 (vacuum valve) and the control valve 17
A control signal for setting the duty ratio to 0% is output to the (atmospheric pressure valve).

Further, in S43 and S44, -α <ΔP <α
If it is determined that (S43, NO, S44, N
O), it means that the pressure Pc in the vacuum chamber 14 is within the target range. Therefore, it is determined in S50 and S51 that the control valves 16 and 17 are closed to maintain the pressure in the chamber 14, and in S47, the duty cycle is set. A control signal for setting the ratio to 0% is output to the control valves 16 and 17.

The configuration of the embodiment of the present invention and the operation thereof have been described above. According to this embodiment, the sub booster 4 is operated according to the average vehicle speed and the average deceleration of the vehicle within a predetermined time.
Since the value of the negative pressure in the diaphragm chamber 13 is changed, and the assisting force for the brake pedal 1 is changed by this, the optimum braking characteristic according to the running state can be obtained.

Further, since the change of the assist force is restricted during the operation of the brake pedal 1, it is possible to avoid the possibility that the change of the assist force gives the driver a feeling of strangeness.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a brake control device according to the present invention.

FIG. 2 is an overall system diagram showing an embodiment of a brake control device according to the present invention.

FIG. 3 is a flowchart showing a main routine of a control example of a brake control device according to the present invention.

4 is a flowchart showing the contents of steps S1 and S2 of FIG.

5 is a flowchart showing the contents of step S3 of FIG.

FIG. 6 is a flowchart showing the contents of step S3 of FIG.

FIG. 7 is a flowchart showing the contents of step S4 of FIG.

FIG. 8 is a flowchart showing the contents of step S5 of FIG.

[Explanation of symbols]

1 brake pedal 2 master cylinder 3 main boosters 4 sub boosters 7,12 diaphragm 8,13 diaphragm chamber 9,15 Check valve 14 Air chamber 16 Control valve (vacuum valve) 17 Control valve (atmospheric pressure valve) 20 control unit 25 Disc brake device 41 Brake switch 42 vehicle speed sensor 43 Pressure sensor

Claims (3)

(57) [Claims] 1. An assist means for assisting a braking force generated by operating a brake operation input means such as a brake pedal, an assist force varying means for changing the assist force generated by the assist means, and the brake operation input means. Brake operation to detect the operation of
A work detecting means, and calculating means for calculating the average vehicle speed and average deceleration of the vehicle within the predetermined time, the assist amount based on the average vehicle speed and average deceleration calculated by said calculating means, at least the average deceleration of the increase in
Increase with the decrease of the average deceleration
The assist amount determining means for controlling the assist force varying means based on the assist amount determined by the assist amount determining means, and the control unit for controlling the assist force varying means based on the detection by the brake operation detecting means.
While the rake operation input means is being operated, the assist force varying means described above is used.
Assist force change regulation that regulates change in assist force due to
Control device for a brake that characterized in that it comprises a means. 2. The assist force change restricting means is the buoy
Change the above assist force while operating the rake operation input means.
Prohibition, and with the end of the operation of the brake operation input means
2. The brake control device according to claim 1, comprising means for permitting a change in the assist force . 3. The assist force change restricting means comprises
While operating the rake operation input means, gradually increase the assist force.
The device according to claim 1, further comprising a changing unit.
The control device of the brake.