JPH04349057A - Anti-skid control device - Google Patents

Abstract

PURPOSE:To reduce vibration of a car in the gear meshing state by sensing the meshing state under the anti-skid control accurately, and changing over the fashion of controlling when the meshing state is sensed. CONSTITUTION:The varying amplitude of the engine speed and the variation period during anti-skid control are calculated (Step 1 thru 4), and 'gear meshing state' flag is set when the varying amplitude is greater than the specified value K1 and the variation period is smaller than its specified value T1 (Step 5 thru 7). This enables changing-over from decompressive to boosting control and vice versa.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid control device operated when applying brakes to a vehicle.

0002

[Prior Art] Generally, when the brakes are applied to a vehicle, the downward slope of the vehicle body speed does not match the downward slope of the wheel speed.
First, the wheel speed drops, the deceleration increases, and eventually the wheels become locked.

Therefore, in an anti-skid control device, when a drop of more than a certain reference value is detected in the wheel speed after applying the brake, the brake hydraulic pressure applied to the wheel is gradually reduced to prevent the wheel from locking. Depressurize and go. When the wheel speed returns due to the pressure reduction, the brake oil pressure is temporarily held at the current oil pressure, then the oil pressure is increased linearly, and then the pressure is increased stepwise (pulse pressure increase).

[0004] As a result, when a drop in wheel speed exceeding a certain reference value is detected again, the brake oil pressure applied to the wheel is gradually reduced, and when the wheel speed returns again, the brake oil pressure is again applied to the wheel. holding, increasing pressure,
Furthermore, pulse pressure is increased. By repeating this process, the wheel speed is lowered to a certain target value (for example, about 80% of the vehicle speed at that time), and the predetermined braking distance is achieved while preventing the vehicle from falling into the locked state. to stop the vehicle.

By the way, when such anti-skid control is performed, when the vehicle is in gear (that is, when the engine load is applied to the wheels via the clutch and gear), when the vehicle is not in gear, If control is performed under similar conditions, the control will not be appropriate for the gear engagement condition, and vehicle vibration (so-called gear engagement vibration) based on the gear engagement condition (i.e., the state where the engine load is applied to the wheels) will occur. occurs significantly.

[0006] Conventionally, therefore, the gear engagement state is estimated based on the manner in which the wheel speed changes detected by the wheel speed sensor incorporated into the anti-skid control system, and when the gear engagement state is estimated, a pressure reduction method is determined. Leave as is (
(It is necessary to reduce the pressure in order to prevent the wheels from locking up.) This was dealt with by changing the way the pressure was increased.

However, during anti-skid control, the wheel speed always fluctuates regardless of the gear engagement state, so there is a problem in that even if the gear engagement state is estimated based on the way the wheel speed fluctuates, it can only be estimated extremely inaccurately. was there. Furthermore, when it is estimated that a gear is engaged in this way, even if only the method of pressure increase is changed, the wheel lock pressure (hydraulic pressure when starting to lock the wheels) and the wheel recovery pressure (wheel There is also a problem in that it is not possible to sufficiently cope with the deviation of the oil pressure (when the speed starts to recover) from the value when the gear is not engaged, and it is not possible to effectively reduce the gear-entering vibration.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and includes an engine rotation sensor in addition to the wheel speed sensor described above in the anti-skid control system. The gear-engaged state is accurately detected based on the detected engine speed fluctuation state, and when the gear-engaged state is detected, the anti-skid control is reliably and appropriately switched (to match the gear-engaged state). This makes it possible to switch both the method of pressure reduction and pressure increase), thereby making it possible to reduce vehicle vibrations caused by gear engagement.

Furthermore, the present invention provides an engine rotation sensor and a wheel speed sensor provided in the anti-skid control system.
In this case, the gear load (corresponding to the gear ratio) is estimated based on the engine rotation speed and the drive wheel speed detected by the drive wheel speed) sensor, and the anti-skid control is applied at that time according to the gear load. This makes it possible to more precisely switch (switching both the pressure reduction and pressure increase methods) to suit the gear load condition, thereby making it possible to more finely reduce the gear-entering vibration.

0010

[Means for Solving the Problems] In order to solve the problems, according to the present invention, there is provided an anti-skid control device including means for detecting the engine speed, the engine speed detected during the control. An anti-skid control device is provided which is characterized in that a gear engagement state is detected based on a fluctuating state of.

Furthermore, according to the present invention, there is provided an anti-skid control device comprising means for detecting engine rotational speed and means for detecting driving wheel speed, the anti-skid control device comprising means for detecting engine rotational speed and driving wheel speed. An anti-skid control device is provided which is characterized in that it determines the load on a gear.

0012

[Operation] According to the above configuration, if the engine is in gear (engine load is applied to the wheels) during anti-skid control, the engine speed will definitely fluctuate, but if it is not in gear, the engine will change. Since the engine speed hardly fluctuates in the idle state, it is possible to accurately detect the gear engagement state based on the variation state of the engine revolution speed detected during the control, and therefore, the gear engagement state can be accurately detected. It becomes possible to correctly switch to the control (switch both the pressure reduction and pressure increase methods), and thereby it becomes possible to reduce vibrations of the vehicle that occur in the gear engagement state.

Furthermore, according to the above configuration, the gear load condition can be almost accurately estimated based on the detected engine speed and drive wheel speed, so that control can be finely tuned to suit the gear load condition. It becomes possible to switch the control (switch both the method of pressure reduction and pressure increase), thereby making it possible to reduce the gear-entering vibration more precisely.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, FIGS. 6 and 7 are flowcharts illustrating a conventional operating procedure of an anti-skid control device. That is, first, when control is started, step 31 becomes NO, and step 32 becomes YES. As a result, at the start of the control, the pressure reduction mode is set in step 33. Next, if the control is not ended in step 34, the process proceeds to step 35, where a mode is determined. (It is usually determined by the flag, and in this case it is in decompression mode.)
If step 32 is NO and control has not been started, or if step 34 is YES and control has ended, the process proceeds to step 48, where control is not started.

As described above, when it is determined in step 35 that the pressure reduction mode is selected, the process proceeds to step 36, and until the pressure reduction mode ends, the process proceeds to step 44, where the pressure reduction output is performed.
Brake oil pressure is gradually reduced.

When the depressurization mode ends in step 36, a holding mode is set in step 37, and the process proceeds to step 38. Until the holding mode ends, the process proceeds to step 45, where a holding output is made, and a predetermined The brake oil pressure held at the value is output. Note that at this time, step 31 is under control, so the answer is YES, and step 34 is
If the control is not ended at step 35, the mode determination at step 35 is the holding mode.

When the holding mode ends in step 38, the pressure increase mode is set in step 39 and the process proceeds to step 40, and until the pressure increase mode ends, the process proceeds to step 46 where the pressure increase output is performed. , the brake oil pressure is increased linearly. At this time as well, the answer is YES in step 31 because the control is in progress, and if the control is not ended in step 34, the mode determination in step 35 is the pressure increase mode.

When the pressure increase mode is completed in step 40, the pulse pressure increase mode is set in step 41 and the process proceeds to step 42, and the process proceeds to step 47 where the pulse pressure increase mode is set until the pulse pressure increase mode is completed. Pressure force is applied, and the brake hydraulic pressure is increased step by step. At this time as well, step 31 is under control, so the answer is YES, and if the control does not end at step 34, step 31 is YES.
Mode determination No. 5 is the pulse pressure increase mode.

When the pulse pressure increase mode ends in step 42, the pressure reduction mode is set again in step 43, and the process proceeds to step 44, where a pressure reduction output is performed. At this time, the answer is YES in step 31 because the control is in progress, and if the control is not ended in step 34, the mode determination in step 35 is the depressurization mode, and from now on, until the control is ended in step 34, Each mode of pressure reduction → holding → pressure increase → pulse pressure increase → pressure reduction → −−−−− is repeatedly set in sequence. In this case, the time during which each of the above modes (for example, pressure reduction mode) is set is determined depending on the speed of the wheel and the like.

FIG. 8 is a system configuration diagram of this type of anti-skid control device, in which when the brake pedal is depressed, the brake oil filled in the master cylinder M/C is applied to each wheel (left and right front wheels, respectively). FL,
It is indicated by FR, and the left and right rear wheels are indicated by RL and RR, respectively. ) Wheel cylinder W/C provided opposite to
The brakes are applied to each wheel. In this case, the actuators corresponding to each wheel (i.e. FL, ACT; FR, ACT; R
L, ACT and RR, ACT) change the brake pressure applied to each wheel. In addition, the EC
U includes wheel speed sensors WS1 to WS for each of the above wheels.
The output side of the master cylinder from 4 is divided into a side C1 that supplies hydraulic pressure to one pair of wheels FR and RL, and a side C2 that supplies hydraulic pressure to the remaining pair of wheels FL and RR, Even if a failure occurs in one hydraulic system, the remaining hydraulic system will provide the brakes. Sensor signals etc. are input.

FIG. 9 shows an example of the detailed configuration of the ECU shown in FIG. Sensor signals from the EGS are input via the input interface (I/F) 11, and signals from various switches (for example, a brake switch that confirms that the brake is pressed) are sent to the level conversion circuit. 12, and a wheel speed sensor W for each wheel.
Sensor signals from S1 to WS4 are input via waveform shaping (pulse shaping) circuits 13 to 16, and a power supply circuit 17 from battery B is further input.

Further, a motor relay MR is connected to the output side of the CPU through a motor relay drive circuit 21.
By turning on the relay MR, the pump motor (
The motor (PM) is activated to return the oil accumulated in the reservoir to the master cylinder M/C when the pressure is reduced. Further, in the event of an abnormality (for example, in the event of a failure), the abnormality lamp L is operated through the lamp drive circuit 22. Further, if there is no abnormality in the ECU, the solenoid relay SR is always turned on through the solenoid relay drive circuit 27. If the solenoid relay SR is on, the actuators (i.e. FR, AC
T; FL, ACT; RR, ACT; and RL, AC
T) is controlled by the CPU.

[0023] Here, the present invention provides an anti-skid control device as described above, in which a gear engagement state is accurately detected based on the fluctuation state of the engine speed detected during the control, and the gear engagement state is detected. In some cases, it is possible to correctly switch to control appropriate for the gear engagement state.

FIG. 1 shows an example of the operation procedure of an anti-skid control device as an embodiment of the present invention. In step 1, the engine speed input from the engine speed sensor EGS to the ECU is sequentially sampled. The low peak value of the engine speed that appears first is detected, and then in step 2, the high peak value of the engine speed that appears next to the low peak value is detected. Then, in step 3, the fluctuation amplitude of the engine speed (the level difference between the high peak value and the low peak value) is calculated, and in step 4, the fluctuation period of the engine speed (the time difference between the high peak value and the low peak value) is calculated. do.

In step 5, it is determined whether the calculated fluctuation amplitude is larger than a predetermined judgment reference amplitude K1, and in step 6, it is determined whether the calculated fluctuation period is shorter than a predetermined judgment reference period T1. If both are YES (that is, if it is detected that the fluctuation amplitude is larger than the predetermined judgment reference amplitude and the fluctuation period is shorter than the predetermined judgment reference amplitude), in step 7, the gear A gear-on state flag is set to indicate that the gear is on. In this way, the fluctuation amplitude and fluctuation period are constantly calculated from the low peak value of the engine speed that appears during anti-skid control and the high peak value of the engine speed that follows, and the calculated fluctuation amplitude and fluctuation period are continuously calculated. The gear engagement state can be accurately detected based on the period value.

In the present invention, when such a gear engagement state is detected during anti-skid control,
Control is performed to reduce vibrations of the vehicle based on the gear engagement state by correctly switching to control appropriate for the gear engagement state (switching both the pressure reduction and pressure increase methods).

FIG. 2 illustrates the operation procedure of an anti-skid control device as another embodiment of the present invention for performing such control. In step 11, the operation procedure shown in FIG. If it is detected that this is the case, first increase the decompression sensitivity in step 12, then advance the decompression stop timing in step 13, prohibit the pressure increase output in step 14, and further increase the pulse pressure increase period in step 15. (i.e., increase the slope of the pulse boost output).

FIG. 3 shows a waveform (FIG. 3(A)) showing a change in wheel speed when control as shown in FIG. 2 is performed when the gear-in state is detected. A comparison is shown with the case where no control is performed (FIG. 3(B)). In other words, when performing the control shown in Fig. 2 above, the depressurization sensitivity is first increased, so as shown in Fig. 3(A), the wheel speed decreases slightly (compared to the case of Fig. 3(B)). At the detection time t1, the pressure reduction a (indicated by the oil pressure of the wheel cylinder, that is, the W/C pressure) is started. In the case of FIG. 3(B), the time point at which pressure reduction a' starts is indicated by t1'.

Next, when performing the control shown in FIG. 2 above, the decompression stop timing is advanced as described above, and the drop in wheel speed does not reach its low peak as shown in FIG. 3(A) above. Before (shown at time t2), the reduced pressure a is stopped and once the W/C pressure is maintained as shown at b. In the case of FIG. 3(B), the stop timing of the pressure reduction a' is near the low peak of the drop in wheel speed, as shown by t2', and then the W/C pressure is reduced to b'.
It is temporarily held as shown in .

Furthermore, when performing the control shown in FIG. 2 above, the pressure increase output (as shown by c' in FIG. 3(B)) is prohibited as described above, and the holding mode shown in b above is set. Pulse pressure increase mode c that immediately increases the oil pressure in stages after
to be transferred to In this case, the pulse pressure increase period of the stepwise pressure increase is shortened to increase the pulse pressure increase gradient S. Note that when the pressure increase output is prohibited in this way, in the flowcharts shown in FIGS. 6 and 7, the pressure increase mode is temporarily set in step 39, but the pressure increase is immediately terminated in step 40 (in this case, (The flag for prohibiting pressure increase is set), therefore, the process immediately proceeds to step 41 without outputting pressure increase, and the pulse pressure increase mode is set.

When the above-mentioned gear-in condition is detected, as described above, the pressure reduction sensitivity when the wheel speed drops is increased, and the decompression stop timing is brought forward (if normal pressure reduction is performed when the gear is in the gear-in condition), (This will result in too much decompression)
As a result, the recovery state of the wheel speed becomes gradual, and an excessive drop in the wheel speed can be prevented by inhibiting pressure increase output and outputting a pulse pressure increase with a relatively steep slope. On the other hand, in the control shown in FIG. 3(B), the pressure reduction performed when the wheel speed drops becomes too much, and the wheel speed recovers more quickly than in the case of FIG. 3(A). However, as a result, the pressure is increased too much and the wheel speed drops significantly again.As shown in Figure 3 (B), this repetition causes the wheel speed to hunt and the vehicle to vibrate. growing. On the other hand, Figure 3 (
In case A), by performing the control shown in FIG. 2 above, the difference between the high peak value and the low peak value of the wheel speed becomes smaller than in the case of FIG. It is longer than in case B) (that is, the wheel speed gradually recovers and no excessive drop occurs), wheel speed hunting is eliminated, and the resulting wheel vibration (vibration when in gear) is reduced. do.

Furthermore, the present invention provides an anti-skid control device as described above, by estimating the gear load (corresponding to the gear ratio) based on the detected engine speed and drive wheel speed. It is possible to more precisely switch the control method (switching both the pressure reduction and pressure increase methods) according to the load state (the position of the gear), and to more precisely reduce the vibration of the vehicle based on the gear engagement state. This is what I did.

FIG. 4 illustrates the operating procedure of an anti-skid control device as yet another embodiment of the present invention for performing such control. First, in step 21, the high peak value of the drive wheel speed is determined for each skid cycle. Detected by the corresponding wheel speed sensor. In this case, the high peak value of the drive wheel speed is taken because the high peak value is close to the vehicle body speed, and the drive wheel speed is detected for each drive wheel (two wheels separately). The following control is performed for each drive wheel according to the detection results.

Next, in step 22, the engine rotation speed at the time when the high peak value of the driving wheel speed is detected is detected by the engine rotation sensor. Then, in step 23, the gear load state (corresponding to the gear ratio) at that time is estimated from the detected high peak value of the drive wheel speed and the engine speed at that time, using the map shown in FIG. 5, for example. be done.

Next, in step 24, the pressure reduction sensitivity (ie pressure reduction start sensitivity) is changed in accordance with the estimated gear load. In this case, the greater the gear load, the higher the pressure reduction start sensitivity. Subsequently, in step 25, the decompression stop timing is changed according to the estimated gear load. In this case, the greater the gear load, the earlier the decompression stop timing will be.

Next, in step 26, the pressure increase output (pressure increase amount) is changed in accordance with the estimated gear load. in this case,
The larger the gear load, the smaller the pressure increase amount, and depending on the gear load, the pressure increase amount is set to 0 (Figure 2
(equivalent to the prohibition of pressure increase in the embodiment). and step 2
At step 7, the pulse pressure increase period (in other words, the pulse pressure increase gradient) is changed according to the estimated gear load. In this case, the larger the gear load is, the shorter the pulse pressure increase period is, thereby increasing the pulse pressure increase gradient.

In this way, the gear load condition at that time is almost accurately estimated based on the high peak value of the drive wheel speed for each skid cycle and the engine speed at that time, and the pressure reduction start sensitivity and pressure reduction are adjusted according to the gear load condition. By changing the stop timing, the amount of pressure increase, and the pulse pressure increase period (in other words, the pulse pressure increase gradient) as described above, hunting in wheel speed as described above can be more precisely prevented, thereby reducing the above-mentioned gearing vibration. can be reduced more precisely.

[0038]

According to the present invention, it is possible to accurately detect the gear engagement state (the state in which the engine load is applied to the wheels) during anti-skid control. Therefore, the control when the geared state is detected can be correctly switched to match the geared state, thereby reducing vibrations of the vehicle due to the geared state and improving ride comfort. Furthermore, according to the present invention, since the load condition of the gear can be estimated almost accurately, the control can be changed more precisely according to the gear load condition, and the gear-in vibration can be more finely reduced to improve ride comfort. Further improvements can be made.

[Brief explanation of the drawing]

FIG. 1 is a flowchart illustrating the operation procedure of an anti-skid control device as an embodiment of the present invention.

FIG. 2 is a flowchart showing the operating procedure of an anti-skid control device as another embodiment of the present invention.

3 is a diagram illustrating wheel speed waveforms obtained by the control shown in FIG. 2 in comparison with those obtained by the prior art; FIG.

FIG. 4 is a flowchart showing the operation procedure of an anti-skid control device as still another embodiment of the present invention.

FIG. 5 is a diagram illustrating a map used for gear load estimation in the flowchart of FIG. 4;

FIG. 6 is a flowchart illustrating the general operating procedure of the anti-skid control device.

FIG. 7 is a flowchart illustrating the general operating procedure of the anti-skid control device.

FIG. 8 is a diagram illustrating a system configuration of an anti-skid control device.

9 is a diagram illustrating the configuration of the ECU shown in FIG. 8. FIG.

[Explanation of symbols]

EGS...Engine rotation sensor WS1 to WS4...Wheel speed sensor M/C...Master cylinder W/C...Wheel cylinder FR, FL, RR, RL...Front wheel and rear wheel FR, AC
T; FL, ACT; RR, ACT; RL, ACT...actuator corresponding to each wheel

Claims (9)

[Claims] 1. An anti-skid control device comprising a means for detecting engine rotation speed, the anti-skid control device being characterized in that a gear engagement state is detected based on a fluctuation state of the engine rotation speed detected during said control. Control device. 2. The anti-skid control device according to claim 1, wherein the decompression start sensitivity is increased when the gear engagement state is detected. 3. The anti-skid control device according to claim 1, wherein the depressurization stop timing is brought forward when the gear engagement state is detected. 4. The anti-skid control device according to claim 1, wherein when the gear engagement state is detected, the pressure increase output is prohibited and the pulse pressure increase gradient is increased. 5. An anti-skid control device comprising means for detecting engine rotational speed and means for detecting driving wheel speed, wherein a gear load is determined based on the detected engine rotational speed and driving wheel speed. An anti-skid control device characterized by: 6. The anti-skid control device according to claim 5, wherein the gear load is determined based on the peak value of the drive wheel speed for each skid cycle and the engine rotational speed at that time. 7. The anti-skid control device according to claim 5, wherein the pressure reduction start sensitivity is increased in accordance with the determined increase in gear load. 8. The anti-skid control device according to claim 5, wherein the decompression stop timing is advanced in accordance with the determined increase in gear load. 9. The anti-skid control device according to claim 5, wherein the pressure increase amount is decreased in accordance with the determined increase in gear load, and the pulse pressure increase gradient is increased.