JP2762872B2 - Variable damping force shock absorber controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force variable shock absorber control device which suppresses squats and nose dives generated during acceleration and deceleration of a vehicle by adjusting the damping force of a shock absorber.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Publication No. 63-63401 discloses a technique in which the deceleration of a vehicle body is calculated, and when the deceleration exceeds a reference value, the damping force of a shock absorber is increased to increase the nose of the vehicle body. Dive suppression is disclosed. Japanese Patent Application Laid-Open No. Sho 60-47717 discloses that an engine rotational acceleration is calculated from an engine rotational speed, and when the acceleration exceeds a reference value, a damping force of a shock absorber is increased to suppress squat of the vehicle. It is disclosed.

[0003]

Here, the damping force of the shock absorber acts to suppress a change in the posture of the vehicle body. Therefore, it is necessary to increase the damping force in response to a change in the posture of the vehicle body. desirable.

However, if the damping force is increased only when the acceleration / deceleration of the vehicle body or the engine rotational acceleration is equal to or higher than the reference value as in the conventional device, the damping force corresponding to a change in posture such as a nose dive or a squat is taken. It is difficult to control.

[0005] This is because the study by the present inventors has revealed that a change in the attitude of the vehicle such as a nose dive or a squat occurs when the degree of change in the acceleration / deceleration of the vehicle body is large. is there.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. Sho 61-150809 and Japanese Utility Model Laid-Open Publication No. Hei 3-1807, an acceleration sensor is mounted on a vehicle body, and a change in the vehicle body acceleration is calculated based on the vehicle body acceleration detected by the acceleration sensor. There has been proposed a device that calculates and controls the damping force in accordance with a posture change such as a nose dive or a squat based on a change in the acceleration.

However, in the above-mentioned conventional apparatus, since a signal from an acceleration sensor is used to detect a change in acceleration, there is a problem that a control response delay is large. That is, since the nose dive and squat are changes in the attitude of the vehicle body after a change in the engine speed or a change in the wheel speed has occurred, a vehicle equipped with an acceleration as in the above-mentioned publication does not completely When the acceleration is detected and the control is started for the first time after a significant posture change has occurred, it may be that a large posture change has already occurred.

In view of the above problems, the inventors of the present application have noticed that a vehicle equipped with an anti-skid control device, which has been increasingly mounted in recent years, is equipped with a wheel speed sensor. By using the signal, it has been found that a change in vehicle body acceleration can be detected without using an acceleration sensor as in the related art.

Therefore, the present invention accurately detects a change in vehicle body acceleration using a wheel speed sensor and adjusts the damping force of a shock absorber in accordance with the change in acceleration to change the attitude of a nose dive, squat, or the like. It is a first object of the present invention to provide a suspension control device that prevents the above.

Further, the present invention provides a suspension control device which calculates a change in engine rotational acceleration and adjusts the damping force of a shock absorber in accordance with the change to prevent a change in posture such as a nose dive or a squat. This is a second object.

[0011]

In order to solve the above-mentioned object, a first damping force variable shock absorber control device according to the present invention comprises a wheel speed sensor for detecting a wheel speed, and a wheel speed sensor for detecting a wheel speed. Of the frequency components included in the wheel speed signal, the frequency components higher than the resonance frequency of the vehicle body
And removing means for removing the body of the co-by said removing means
To the wheel speed signal, which has only frequency components below the vibration frequency.
The vehicle body longitudinal acceleration is calculated by a predetermined arithmetic expression based on the vehicle body acceleration calculating means.
A change calculating means for calculating a change in the vehicle body acceleration based on the vehicle longitudinal acceleration calculated in the above manner;
Control means for outputting a control signal so as to adjust the damping force of the shock absorber based on the variation of the vehicle body acceleration calculated by the output means; and damping of the shock absorber in response to a control signal from the control means. Adjusting means for adjusting the force.

According to a second aspect of the present invention, there is provided a variable damping force shock absorber control device, comprising: an engine speed detecting means for detecting an engine speed; and an engine speed acceleration calculating means for calculating an engine speed from the engine speed. A change calculating means for calculating a change in the engine rotational acceleration from the engine rotational acceleration; andadjusting means for adjusting a damping force of the shock absorber based on the change in the engine rotational acceleration. I do.

[0013]

According to the above construction, the damping force variable shock absorber control device according to claim 1 removes a frequency component larger than the resonance frequency of the vehicle body from the frequency components included in the wheel speed signal detected by the wheel speed sensor. And the body
To the wheel speed signal, which has only frequency components below the vibration frequency.
The longitudinal acceleration of the vehicle body is calculated based on a predetermined arithmetic expression .

Here, the reason why a frequency component higher than the resonance frequency of the vehicle body is removed from the frequency components included in the wheel speed signal will be described. The wheel speed signal detected by the wheel speed sensor includes various frequency components including the resonance frequency of the vehicle body (spring resonance frequency) and the unsprung resonance frequency. As described above, in the present invention, the change in the posture of the vehicle body is suppressed. Therefore, when a frequency component higher than the resonance frequency of the vehicle body is included, it is highly likely that the change in the posture of the vehicle body cannot be accurately determined. . sand
That is, the unsprung resonance frequency component includes a normal road surface condition (road surface
Changes in wheel behavior due to unevenness, etc.)
This hinders detection of changes. Also, this unsprung resonance frequency
The number component is the resonance frequency of the vehicle body, that is, the sprung resonance frequency.
Value and smaller than the sprung resonance frequency
The resonance frequency range is almost
Applicant's earnest experiment results that it has no adverse effect
Revealed. Therefore, to remove large frequency components than the resonance frequency of the vehicle body by removing means, shock
Only frequency components lower than the resonance frequency of the vehicle body to be used for attitude control by the absorber are extracted.

As described above, the resonance frequency of the vehicle body is lower than the resonance frequency.
Detected based on a signal containing only the resonance frequency component of
It is possible to calculate the change in the vehicle body acceleration using the vehicle longitudinal acceleration.
Thus, a change in the longitudinal acceleration of the vehicle body can be accurately detected.
Then, looking at the change in the longitudinal acceleration of the vehicle,
If you adjust the damping force of the absorber, you should actually suppress it
While accurately detecting when the posture change has occurred in the vehicle,
Sharp control can be realized. Also, the change in the vehicle attitude is
If the rear acceleration is constant, even if the vehicle longitudinal acceleration is positive
Even if the value is large in the direction or in the negative direction,
Do not give that much nose dive feeling, squat feeling
No. However, acceleration changes from constant body longitudinal acceleration
If there is, even if there is body longitudinal acceleration itself
Even if it is small, the occupant has a large nose dive feeling
Gives a squat feeling. Therefore, the vehicle longitudinal acceleration
If you adjust the shock absorber based on the change,
Control in accordance with changes in vehicle body posture,
When the staff feels the most change in posture, appropriate control can be realized.
You.

According to the second aspect of the present invention, since the damping force of the shock absorber is adjusted based on the change in the engine speed, the posture change to be actually suppressed can be reduced. The posture change gives a strong sense to the occupant when
The damping force of the shock absorber can be adjusted at the timing when the situation is accurately detected .

[0017]

Next, a first embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention.

In FIG. 1, an electronic control unit (ECU) 1
Comprises a CPU 1-1, a ROM 1-2, a RAM 1-3, and the like, and executes a predetermined arithmetic processing. The wheel speed sensors 2 correspond to at least the left and right front wheels or the left and right rear wheels,
It is arranged near each wheel and outputs a signal corresponding to the rotation speed of each wheel. The wheel speed sensors 2 may of course be provided for each of the four wheels of the vehicle. The output signal from the wheel speed sensor 2 is input to the ECU 1 via the input buffer 4. The input buffer 4 shapes and amplifies the signal generated by the wheel speed sensor 2 and outputs the signal to the ECU 1.

The shock absorbers 6 to 9 are respectively provided between the vehicle body and the wheels corresponding to the four wheels of the vehicle, and are configured so that the generated damping force can be changed. The drive circuits 10 to 13 adjust the damping force generated by the shock absorbers 6 to 9 according to a control signal from the ECU 1. Also,
Reference numeral 14 denotes an ignition switch, and when this switch is turned on, power is supplied to a control system including the ECU 1.

FIG. 2 is a flowchart showing the contents of processing executed by the ECU 1. FIG. 3 is a waveform diagram showing the state of each signal when the vehicle is accelerated or decelerated. In FIG.
In step 100, the wheel speeds Vl and Vr of the left and right wheels are calculated based on the signal output from the wheel speed sensor 2. The wheel speeds Vl and Vr increase and decrease, for example, as shown in FIG. 3 by the driver's accelerator operation. In step 110, the average speed of the wheel speeds Vl, Vr of the left and right wheels calculated in step 100 is calculated, and the speed obtained by subjecting the average speed to low-pass filtering (cutoff frequency 3 Hz) is obtained as the vehicle body speed VBF. . By this low-pass filtering, only the resonance frequency component on the spring is extracted from various frequency components included in the wheel speed. That is, a wheel speed signal fluctuation based on a change in the posture of the vehicle body is extracted. And this body speed VBF
Is calculated based on the following equation.

[0021]

## EQU1 ## GBF (i) = K.multidot. (VBF (i) -VBF (i-1)) / T where T is the calculation cycle of the flowchart shown in FIG.

The calculated vehicle body acceleration GBF changes, for example, as shown in FIG. In step 120, a change ΔGBF of the vehicle body acceleration GBF calculated in step 110 within a predetermined time is calculated by the following equation.

[0023]

ΔGBF (i) = GBF (i) −GBF (i−1) Then, based on the change ΔGBF in the vehicle body acceleration, the magnitude of the damping force of the shock absorbers 6 to 9 is set to two levels (soft, A process 200 for outputting a command signal for switching to hardware is executed.

The command signal output processing 200 will be described. First, at step 210, it is determined whether or not the damping force has already been switched to hardware. If not switched to hardware, go to step 220,
It is determined whether the condition for switching to hardware is satisfied. The hardware switching condition is as follows.

[0025]

## EQU3 ## Anti-square control ΔGBF ≧ k _SH1 Anti-dive control ΔGBF <k _DH1 That is, as shown in FIG.
Becomes harder when the reference value becomes equal to or more than the switching reference value k _SH1 for anti-squat control, or when the value becomes smaller than the switching reference value k _DH1 for anti-dive control. In order to actually switch the damping force to hardware, the above condition may be satisfied a plurality of times in succession.

[0026] At step 220, the change in ΔGBF of the vehicle body acceleration is determined to be smaller than the squat switching reference value k _{SH 1,} or it dives switching reference value k _DH1 above, the process proceeds to step 240, the damping force A command signal for softening is output, and this routine ends. On the other hand, if it is determined that the variation ΔGBF of the vehicle body acceleration is equal to or greater than the squat switching reference value k _SH1 or smaller than the dive switching reference value k _DH1 , the process proceeds to step 250, and the command to set the damping force to hard is executed. A signal is output, and this routine ends.

If it is determined in step 210 that the damping force has been switched to hard, the process proceeds to step 230, in which it is determined whether the condition for returning to software in anti-squat control or anti-dive control has been satisfied. I do. This soft return condition is as follows.

[0028]

## EQU4 ## Anti-square control ΔGBF <k _SH2 Anti-dive control ΔGBF ≧ k _DH2 That is, in the anti-squat control, when the change ΔGBF in the vehicle body acceleration is smaller than the squat return reference value k _SH2 , in the anti-dive control, When the dive return reference value _kSH2 or more, the damping force is switched to soft. As the return condition, as shown in FIG. 3, the squat return reference value k _SH2 is made smaller than the squat switch reference value k _SH1 (the dive return reference value k _DH2 is made larger than the dive switch reference value k _SH1. ). The change ΔGBF in the vehicle acceleration is the squat return reference value k.
_The damping force is switched softly when the time when it becomes smaller than _SH2 (the dive return reference value _kDH2 or more) continues for a predetermined time Td.

By adding such conditions, the damping force can be switched softly when the magnitude of the change ΔGBF in the vehicle body acceleration is surely reduced. In addition,
Only one of the above conditions may be added, and the predetermined time Td is set to be longer as the vehicle speed becomes higher, or to be longer as the peak value of the variation ΔGBF of the vehicle body acceleration becomes larger. It may be variable.

Next, a second embodiment of the present invention will be described. In the above-described first embodiment, the variation ΔGBF of the vehicle body acceleration is used.
In the second embodiment, the anti-square control and the anti-dive control are performed based on the change ΔdNe of the engine rotational acceleration dNe.

Particularly in a vehicle having a manual transmission,
The engine rotation speed Ne increases almost in the same manner as the increase in the speed of the vehicle. Therefore, the engine rotational acceleration dNe is:
It can be regarded as a signal corresponding to the acceleration of the vehicle. Moreover, when the anti-squat control is performed using the change ΔdNe in the engine rotational acceleration instead of the change ΔGBF in the vehicle body acceleration, the change in the attitude of the vehicle (squart) can be detected more quickly and the damping force can be increased. There is.

That is, as shown in FIG. 4, when the driver starts the accelerator operation and opens the throttle valve of the engine, first, the intake pipe pressure Pm of the engine increases, and the engine speed Ne slightly increases with a delay. To rise. The driving torque generated by the engine starts increasing almost simultaneously with the increase in the engine speed Ne, and gradually decreases as the rate of increase in the engine speed decreases.

Here, the relationship between the change in the attitude of the vehicle when the squat occurs and the driving torque T will be described. Assuming that the force for generating squat on the vehicle is squat force Ws, the distance from the center of gravity of the vehicle body to the drive wheel is l, the distance from the center of gravity of the vehicle body to the road surface is h, and the inertia of the drive wheel is I,
The squat force Ws is calculated by the following equation.

[0034]

Ws = h × (T−I × dω) / l That is, the squaring force Ws is obtained by subtracting the force required to rotate the driving wheel having the inertia I from the driving torque T (T−I × dω). Therefore, in order to appropriately prevent squat, it is desirable to increase the damping force when the driving torque starts to increase.

FIG. 5 shows the relationship among the driving torque T, the squaring force Ws, and the driving wheel speed Vω. As is clear from FIG. 5, the squat force Ws also increases with the increase in the driving torque T, and thereafter, the two change substantially similarly. On the other hand, the drive wheel speed Vω starts increasing slightly after the drive torque T and the squat force Ws increase (about 0.1 second).

Therefore, if the anti-squat control is performed based on the variation ΔGBF of the vehicle body acceleration based on the wheel speed V such as the driving wheel speed, it is inevitable that a delay occurs in the initial stage of the change in the attitude of the vehicle. However, as described above, the engine speed Ne starts increasing almost at the same time as the drive torque T. Therefore, if anti-squat control is performed using the change ΔdNe of the engine rotation acceleration based on the engine speed Ne, the delay will be longer. Can be reduced.

In the second embodiment, as shown in FIG.
An engine speed sensor for detecting the speed of an engine (not shown) is provided instead of the wheel speed sensor of the first embodiment. The output signal from the engine speed sensor 3 is also subjected to EC shaping after waveform shaping and amplification through the input buffer 5.
It is input to U1.

FIG. 7 is a flowchart showing the processing contents of the ECU 1 in the second embodiment. In FIG. 7, in step 300, the engine speed Ne is calculated based on the output signal from the engine speed sensor 3. In step 310, based on the engine speed Ne calculated in step 300, the engine rotational acceleration dN is calculated by the following equation.
e is calculated.

[0039]

DNe (i) = (Ne (i) -Ne (i-1)) / T where T is a calculation cycle.

In step 320, based on the engine rotational acceleration dNe calculated in step 310, the change ΔdN in the engine rotational acceleration dNe within a predetermined time is calculated by the following equation.
e is calculated.

[0041]

In the step 330, a change ΔdNe of the engine rotational acceleration dNe calculated in the step 320 within a predetermined time is calculated. ΔdNe (i) = ΔdNe (i) −ΔdNe (i-1)
, A damping force switching command signal output process is executed. This processing is basically performed by the command signal output processing 20 of the first embodiment.
0, except for a hard switching condition and a soft return condition.

The hardware switching condition in the second embodiment is as shown in the following equation.

[0043]

ΔdNe ≧ k _SH3 That is, when the change ΔdNe of the engine rotational acceleration becomes equal to or greater than the switching reference value k _SH3 , the damping force is switched to hardware.

Note that a vehicle speed condition may be added to the hardware switching condition. That is, for example, when the vehicle speed is 20 k
Only when the vehicle is in a low vehicle speed range of m / h or less, the hard switching condition is determined and the damping force is switched. This is based on the fact that squats occur in a vehicle when the vehicle accelerates rapidly from a low vehicle speed range, and rarely occur in a medium to high speed range. And, by further limiting the conditions for switching the damping force to hard by anti-square control,
The frequency of switching to hardware can be reduced to improve ride comfort.

On the other hand, the soft return condition is that the change ΔdNe of the engine rotational acceleration becomes smaller than the return reference value k _SH4 as shown in the following equation.

[0046]

ΔdNe <k _SH4 As with the first embodiment, further conditions can be added according to the duration and the level of the return reference value k _SH4 , as described in the first embodiment.

As described above, the squat control based on the change ΔdNe in the engine rotational acceleration is effective in reducing the delay from the occurrence of the squat in the vehicle to the start of the control.

However, in a vehicle equipped with an automatic transmission, there is a case where the engine speed and the vehicle speed do not accurately correspond to each other due to the function of the torque converter existing between the engine and the drive wheels. This is because slippage occurs in the torque converter particularly when the engine speed rapidly increases. However, if this phenomenon is used in reverse, it is possible to more easily detect the occurrence of the squat of the vehicle.

That is, in a vehicle equipped with an automatic transmission (torque converter), if the engine speed rises sharply, slippage occurs in the torque converter, so that the drive torque T is transmitted to the drive shaft (drive shaft). Has a time delay. For this reason, even if the amount of change ΔdNe of the engine rotation acceleration is not calculated, the speed change of the engine speed, that is, the engine rotation acceleration dNe, is not required.
Then, the subsequent increase in the driving torque T can be detected (the driving torque T and the vehicle body acceleration GBF are in a correspondence relationship,
When the driving torque T increases, the vehicle body acceleration GBF also increases), and appropriate anti-squat control can be performed based on the engine rotation acceleration Ne.

In this case, as the processing in the ECU 1, the processing in step 320 of the flowchart shown in FIG. 7 may be omitted, and the engine rotational acceleration dNe calculated in step 310 may be directly compared with the reference value. For this reason,
The processing contents in the ECU 1 can be simplified. As described above, the anti-quote control is performed when the engine rotational acceleration dNe or the change ΔdNe is equal to or more than a positive predetermined value. Conversely, when the engine rotational acceleration dNe or the change ΔdNe is equal to or less than a negative predetermined value, the engine brake is determined and the anti-dive control may be performed.

Next, a third embodiment of the present invention will be described. In the first embodiment, the anti-squat control and the anti-dive control are performed based on the variation ΔGBF of the vehicle body acceleration. In the second embodiment, the anti-square control is performed based on the variation ΔdNe of the engine rotation acceleration dNe. Was explained.

In the third embodiment, anti-square control is performed by combining the first and second embodiments. In this case, as shown in FIG. 8, the start of the anti-squat control is mainly defined by the change ΔdNe of the engine rotational acceleration dNe, and the end is mainly defined by the change ΔGBF of the vehicle body acceleration. If the variation ΔGBF of the vehicle body acceleration decreases, the squat force actually generated in the vehicle also decreases. For this reason, according to the third embodiment, it is possible to increase the damping force of the shock absorber by capturing a change in the attitude (square) of the vehicle more quickly, and to prevent the change in the attitude of the vehicle body by increasing the damping force. It is possible to reliably maintain the necessary time.

The configuration of the third embodiment differs from the first and second embodiments only in that it has both a wheel speed sensor and an engine speed sensor, and the other configurations are the same.

FIG. 9 shows the processing contents of the ECU 1 in the third embodiment. In FIG. 9, at step 400, the wheel speed, at step 410, the vehicle acceleration, at step 4
At 20, a change ΔGBF in the vehicle body acceleration is calculated. Also, at step 430, the engine speed is set at step 4
At 40, the engine rotational acceleration is calculated, and at step 450, the change ΔdNe of the engine rotational acceleration is calculated.

Then, the change ΔGBF of these vehicle body accelerations
And the change amount ΔdNe of the engine rotational acceleration,
A process 500 for outputting a command signal for switching the magnitude of the damping force of the shock absorbers 6 to 9 to two levels (soft and hard) is executed.

At step 510, it is determined whether or not the damping force has already been switched to hardware. If not, the process proceeds to step 520. In step 520, a change ΔdNe in the engine rotational acceleration is calculated.
Is greater than or equal to the switching reference value k _SH3, and in step 530, the change ΔGBF in the vehicle body acceleration is determined by the switching reference value k _SH3.
It is determined whether or not _SH1 or more has been reached. If it is determined at step 520 or 530 that either one is satisfied, the process proceeds to step 580, and the damping force is switched to hard. On the other hand, when neither of the conditions of steps 520 and 530 is satisfied, the process proceeds to step 540, and the damping force is made soft.

If it is determined in step 510 that the damping force has been switched to hardware, the process proceeds to step 550. At step 550, it is determined whether or not the change ΔdNe of the engine rotational acceleration is smaller than the return reference value k _SH4 . At step 560, it is determined whether or not the change ΔGBF of the vehicle body acceleration is smaller than the return reference value k _SH2. judge. If one of the determinations in steps 550 and 560 is not satisfied, the process proceeds to step 580.
And leave the damping force hard. On the other hand, when both of the conditions of steps 550 and 560 are satisfied, the process proceeds to step 570, and it is determined whether or not a predetermined time Td has elapsed since both conditions are satisfied. And
If the predetermined time Td has elapsed, the process proceeds to step 540 to switch the damping force to soft, and if not, the process proceeds to step 540 to maintain the damping force as hard.

As described above, the start of the anti-squat control is mainly based on the change ΔΔ in the engine rotational acceleration dNe.
The end is mainly defined by the change ΔGBF of the vehicle body acceleration. Therefore, as a condition for switching the damping force to hardware, only the process of step 520 may be executed, and the process of step 530 may be omitted. Also, as a condition for returning the damping force to software, step 56
Only the process of 0 may be executed, and the process of step 550 may be omitted. This makes it possible to simplify the arithmetic processing in the ECU 1.

In the above-described second and third embodiments, the anti-square control is performed based on the change ΔdNe of the engine rotation acceleration dNe. Instead, the variation ΔdP of the differential value of the intake pipe pressure Pm of the engine
It is also possible to use m. As described above, the rise of the intake pipe pressure Pm of the engine and the rise of the engine speed Ne are related, and the intake pipe pressure Pm rises slightly earlier.

In a vehicle equipped with an automatic transmission (torque converter), the engine rotational acceleration dNe may be used instead of the change ΔdNe in the engine rotational acceleration for the same reason as described in the second embodiment. .

Next, a fourth embodiment of the present invention will be described. In the third embodiment described above, the variation ΔGBF of the vehicle body acceleration is used.
And anti-square control is performed by combining the change ΔdNe of the engine rotational acceleration dNe.
In the embodiment, the anti-dive control is performed by combining the change ΔGBF of the vehicle body acceleration and the signal from the stop switch.

Therefore, in the fourth embodiment, as shown in FIG. 10, in addition to the configuration of the first embodiment, a stop switch 1
5 is provided. The stop switch 15 outputs a signal when the driver depresses the brake pedal.

In the fourth embodiment, the change ΔG
Since anti-dive control is performed using a signal from the stop switch 15 in addition to BF, anti-dive control with excellent responsiveness can be performed. That is,
As shown in FIG. 11, the damping force can be immediately increased at the start of braking or at the end of braking, so that a change in vehicle attitude (dive and return from dive) that occurs thereafter can be reliably prevented.

FIG. 12 shows the contents of processing executed by the ECU 1 in the fourth embodiment. In FIG. 12, step 6
By the processing from 00 to step 620, the first
As in the embodiment, the variation ΔGBF of the vehicle body acceleration is calculated. At step 630, a stop switch signal is fetched, and it is detected whether or not the level has changed from the previously fetched stop switch signal.

Based on the level change of the stop switch signal and the change ΔGBF of the vehicle body acceleration, a damping force switching command signal output process 700 is executed. In the command signal output processing 700, first, in step 710, it is determined whether or not the damping force has already been switched to hardware. If it has not been switched to hardware, the process proceeds to step 720, and it is determined whether or not the level of the stop switch signal has changed. If there is a level change, step 7
Proceed to 70 and switch the damping force to hardware. On the other hand, if there is no level change, the routine proceeds to step 730, where it is determined whether or not the condition for switching the damping force to hardware is satisfied based on the change ΔGBF in the vehicle body acceleration. Step 7
The processing in steps 50 and 760 is for determining the return of the damping force to software based on the change ΔGBF in the vehicle body acceleration, and is the same as in the above-described first embodiment and the like.

As described above, in the fourth embodiment, the damping force is immediately increased according to the level change of the stop switch signal, and thereafter, the damping force is switched to soft according to the change ΔGBF of the vehicle body acceleration. , Excellent responsiveness,
In addition, it becomes possible to perform anti-dive control appropriately corresponding to a change in the posture of the vehicle body.

The process of increasing the damping force by changing the level of the stop switch signal is performed, for example, when the speed of the vehicle is six.
It may be executed only when the speed is 0 km / h or more. This is because when the driver performs braking at a high speed, there is a high possibility that a large change in posture (dive) will occur (for example, rapid braking often occurs).

At the start of the anti-dive control, the determination may be made only by the level change of the stop switch signal. In this case, step 7 in the flowchart of FIG.
Step 30 can be omitted.

Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the vehicle body acceleration GBF and the variation ΔGBF of the vehicle body acceleration are calculated in the same manner as in the first embodiment, and the two are combined to perform anti-squat control and anti-dive control. The fifth embodiment will be described by taking anti-square control as an example.

That is, as shown in FIG. 13, a hard switching reference value k for comparison with the variation ΔGBF of the vehicle body acceleration.
_0, and a soft release reference value k _1, is set based on the vehicle acceleration GBF. As is clear from FIG. 13, the relationship between the hard switching reference value k _{0, the} soft return reference value k _1, and the vehicle acceleration GBF is such that as the vehicle acceleration GBF increases, the hard switching reference value k ₀ and the soft return reference value become larger. map as k ₁ decreases has been set. For this reason, as the vehicle body acceleration GBF increases, the damping force can be easily switched to hardware, and a change in the attitude of a small vehicle can be suppressed, thereby improving the running stability of the vehicle.

FIG. 14 is a flowchart showing the contents of processing executed by the ECU 1 in the fifth embodiment. In addition,
This flowchart is the same as the flowchart shown in FIG. 2 until the process of calculating the variation ΔGBF of the vehicle body acceleration is performed, so that the process is omitted.

In FIG. 14, in step 800, as shown in FIG. 13, a switching reference value k ₀ and a damping force for hardly switching the damping force are set based on the vehicle body acceleration GBF according to a map which is set and stored in advance. determining a release reference value k ₁ for returning from the hard to soft. The processing from step 810 to step 860 switches the damping force by comparing the change ΔGBF of the vehicle body acceleration with the reference values k ₀ and k ₁ , as in the first embodiment and the like.

In the above description, the processing for suppressing the squat that occurs when the vehicle is accelerated has been described. However, the dive that occurs when the vehicle is decelerated can be suppressed by the same processing.

Further, as shown in FIG.
Multiple maps are set according to the vehicle speed range, such as the vehicle speed range and high vehicle speed range.
May be set. In this case, the vehicle speed range becomes higher
The smaller the vehicle acceleration GBF, the harder the switching reference value
k_0,And soft return reference value k ₁Is set to be smaller
I do. As a result, the damping force is further increased in the middle and high speed ranges.
Because it is easy to switch to hardware, running stability of the vehicle
Properties can be further improved.

In the fifth embodiment, the vehicle acceleration GBF and the change ΔGBF of the vehicle acceleration are calculated, and the squat control and the dive control are performed by combining the two. However, the engine rotation acceleration dNe and the change in the engine rotation acceleration are calculated. ΔdN
It goes without saying that the same control can be performed by calculating e and combining them.

Next, a sixth embodiment of the present invention will be described. In the above-described fifth embodiment, the squat control and the dive control are performed by combining the vehicle body acceleration GBF and the variation ΔGBF of the vehicle body acceleration. In the sixth embodiment, the spring constant of the suspension is adjusted by the vehicle body acceleration GBF. The damping force of the suspension is adjusted by the change ΔGBF of the vehicle body acceleration.

For this reason, the fifth embodiment is based on the premise that the spring constant and the damping force of the suspension can be adjusted independently of each other. One example of this system is shown in FIG. In FIG. 16, reference numerals 30 to 33 denote air springs having an air chamber therein, and the spring constant can be changed by adjusting the pressure of the air chamber. 34
Is an air pressure adjusting device including an air compressor, and adjusts the air pressure of the air springs 30 to 33. The air pressure adjusting device 34 generates an air pressure according to a command signal from the ECU 1.

FIG. 17 is a flowchart showing the processing executed by the ECU 1 in the fifth embodiment. In this flowchart, the processing up to the calculation of the change ΔGBF in the vehicle body acceleration is the same as that in the flowchart shown in FIG. 2, so that the processing is omitted.

In FIG. 17, steps 900 to 95
The processing up to 0 switches the damping force by comparing the variation ΔGBF of the vehicle body acceleration with the respective reference values, as in the above-described first embodiment and the like.

In step 960, it is determined whether or not the spring constant has already been switched to hardware. If not, the process proceeds to step 970. In step 970, the vehicle body acceleration GBF is set to the acceleration reference value F _SH1
It is determined whether or not the above has been _achieved , or whether or not it has become smaller than the deceleration reference value _FDH1 . In this determination, if either one of the conditions is satisfied, the process proceeds to step 1010, and the spring constant is switched to hardware. On the other hand, if none of the conditions is satisfied, the routine proceeds to step 980, where the spring constant is made soft.

If it is determined in step 960 that the spring constant has been switched to hardware, the process proceeds to step 990. In step 990, the vehicle acceleration GBF
Is smaller than the acceleration return reference value F _SH2 , or is greater than or equal to the deceleration return reference value F _DH2 . If neither condition is satisfied, step 10
Proceed to 10 and leave the damping force hard. On the other hand, if either condition is satisfied, step 1000
To determine whether or not a predetermined time TdG has elapsed since the condition was satisfied. If the predetermined time TdG has elapsed, the routine proceeds to step 980, in which the damping force is switched to soft. If not, the routine proceeds to step 1010, in which the damping force is maintained as hard.

By such control, it is possible to suppress a change in the posture of the vehicle body such as a dive and a squat, and to maintain a stable posture when the vehicle body posture is not actually changing. That is, when the variation ΔGBF of the vehicle body acceleration is small and the posture of the vehicle body does not change much, it is considered that the spring force of each of the air springs 30 to 33 and the vehicle body are in a balanced state. At this time, as the vehicle acceleration GBF increases, the air springs 30 to
If the spring force of 33 is increased (the spring constant is made hard), the posture of the vehicle body is stabilized with a more nearly horizontal inclination.

In the above-described sixth embodiment, an example has been described in which the spring constant is changed by the air pressure of the air spring. However, the torsional elastic force of the stabilizer may be changed according to the vehicle body acceleration GBF. As described above, since the stabilizer capable of adjusting the torsional elastic force is known, the description of the configuration is omitted.

In the first to sixth embodiments described above, the magnitude of the damping force is switched to two levels, but may be switched to three or more levels.
In this case, each reference value is set according to the level of the magnitude of the damping force, and is compared with the magnitude of the variation ΔGBF of the vehicle body acceleration and the variation ΔdNe of the engine rotation acceleration. For example, in the first embodiment, when the magnitude of the damping force is switched to three levels of soft, medium, and hard, the squat switching reference value k _{SM1 and the} return reference value k _SM2 corresponding to the medium correspond to the hardware. It is set to a value smaller than the squat switching reference value k _{SH1 and the} return reference value k _SH2 . Then, the variation ΔGBF of the vehicle body acceleration becomes equal to or more than the squat switching reference value k _SM1 corresponding to the medium,
If the value is smaller than the squat switching reference value k _SH1 corresponding to hardware, the damping force is switched to medium.

Next, a seventh embodiment will be described. Seventh
The second embodiment is different from the second embodiment in which antisquat control is performed using the engine rotation acceleration (or a change thereof).
In order to prevent a malfunction at the time of starting the engine, the anti-squat control is prohibited until the following damping force switching permission condition is satisfied.

The engine speed Ne ≧ k _NE (for example, k
_NE = 500 rpm) After the above conditions are satisfied, the vehicle speed becomes the vehicle speed V _{BF for the} first time.
When ≧ k _VB (for example, k _VB = 10 km / h).

The configuration of this embodiment is the same as that of the second embodiment. The processing contents of the ECU 1 in the present embodiment will be described based on the flowchart of FIG. 18 focusing on differences from the second embodiment.

At step 322, the vehicle speed _VBF is calculated from the signal of the wheel speed sensor (similar to the first embodiment) in the same manner as in the first embodiment. In step 324, it is determined whether or not both of the above-described damping force switching permission conditions are satisfied. If not, the damping force is not switched, and this routine ends. On the other hand, in step 324, both of the damping force switching permission conditions are satisfied. If it is determined that the condition is satisfied, the process proceeds to step 330, and a damping force switching command signal is output based on the engine rotational acceleration (or the amount of change thereof).

When it is determined in step 324 that the condition for permitting the switching of the damping force is not satisfied, the reference is provided by replacing the switching reference value k _SH3 shown in FIG. 8 with a large value instead of ending the routine. After correcting the value k _SH3 to a large value, the process may proceed to step 330 so that the damping force is not switched as a result.

In place of the switching permission condition,
The following conditions may be used, in which case the wheel speed sensor and the vehicle speed calculation (step 322) means can be eliminated from the components.

Engine speed ≧ k _NE (for example, 500r
pm) for a predetermined time (for example, 3 seconds). Next, an eighth embodiment will be described. The eighth embodiment is different from the third embodiment in that antisquat control is prohibited until both of the damping force switching permission conditions are satisfied in order to prevent a malfunction at the time of engine start. Same as the example.

Next, differences from the third embodiment will be mainly described with reference to the flowchart shown in FIG. Step 46
At 0, the vehicle speed V _BF is calculated in the same manner as in the first embodiment.
In step 470, it is determined whether or not the damping force switching permission condition is satisfied.
Go to 0 and do not switch the damping force while keeping it soft. On the other hand, the damping force switching換許friendly conditions in step 470, but proceeds to step 510 if both satisfied, the variation of the third embodiment similarly to the engine rotational acceleration ΔdNe and, switching the damping force in response to variation .DELTA.G _BF of the vehicle body acceleration Perform anti-square control.

[0093] Further, when the damping force switching換許friendly conditions not satisfied in step 470, by a such process proceeds to step 530, may control the damping force in response to variation .DELTA.G _BF least vehicle acceleration. The vehicle squat state immediately after engine start according to the control method by detecting only by the .DELTA.G _BF the engine rotational acceleration without, it is possible to perform the damping force control, at immediately after the engine start start also vehicle squat Can be suppressed.

Note that instead of the switching permission condition,
Conditions may be used as described above. Next, a ninth embodiment will be described.

In the ninth embodiment, the engine rotational acceleration Δd
It characterized performing squat control Ne the change amount Δθ in the throttle opening θ instead of in combination with variation .DELTA.G _BF of the vehicle body acceleration.

Therefore, the present embodiment has a configuration provided with a throttle sensor. FIG. 20 shows the processing contents of the ECU 1 in this embodiment. Hereinafter, steps having the same processing contents as those of the third embodiment are denoted by the same step numbers, and description thereof is omitted.

At steps 422 and 424, the throttle opening θ and the change Δθ of the throttle opening per unit time are calculated from the throttle sensor signal. Hereinafter, the throttle opening change Δθ and the vehicle acceleration change ΔG
A process 500A for outputting a command signal for switching the magnitude of the shock absorber damping force to two levels (soft and hard) based on the _BF is executed. In step 500A, steps 520 and 550 of the third embodiment are replaced with steps 525 and 525, respectively.
555 and the others are the same, so step 5
Only 25 and 555 will be described.

In step 525, it is determined whether or not the change in the throttle opening is equal to or greater than the reference value k _{SHS for} switching Δθ. In step 555, it is determined whether or not the change Δθ in the throttle opening is smaller than the return reference value k _sh6 .

Thus, the change Δθ in the throttle opening can be obtained.
By a possible damping force switching control before the vehicle attitude change, further, it is possible to end the control at the timing when the vehicle posture change by variation .DELTA.G _BF of the vehicle body acceleration has subsided.

The switching of the damping force is not limited to two stages, but may be performed in multiple stages or continuously. Next, a tenth embodiment will be described.

Engine rotation acceleration (or its change)
In contrast to the second embodiment in which anti-square control is performed by using a vehicle, the tenth embodiment employs a configuration in which damping force is switched by combining vehicle body speed information, thereby preventing unnecessary damping force switching in a vehicle speed region where squatting is unlikely to occur. It is characterized by doing. Further, the configuration of this embodiment is different from the first and second embodiments in that both the wheel speed sensor and the engine speed sensor are provided, and other configurations are the same.

FIG. 21 shows the processing contents of the ECU 1 in this embodiment. The following description focuses on differences from the second (or first) embodiment, and the same processing contents are denoted by the same step numbers and description thereof is omitted.

At step 100, the left and right wheel speeds Vl, V
r, and in step 105, the wheel speeds V1, V
subjecting the low-pass filtering the mean value of r (the cut-off frequency f _c = 3 _HZ) determining the vehicle speed V _BF.

After calculating the engine rotational speed Ne in step 300, the engine rotational acceleration dNe is calculated in step 310.
(And a change ΔdNe in the engine rotational acceleration) is calculated. In step 335, it is first determined whether or not to switch the damping force to hardware according to dNe (or ΔdNe) as in the second embodiment, and the vehicle speed V _BF is set to a predetermined value A (for example, 50 km / h). If less than dNe (or ΔdN
The damping force is switched according to the determination result in e). Conversely, if the vehicle speed V _BF is equal to or greater than the predetermined value A, the damping force is switched regardless of the determination result in dNe (or ΔdNe). Not performed. If the squat control is already performed and the damping force is hard, the damping force is returned to the soft state when the damping force is equal to or more than a predetermined value B (for example, 70 km / h) provided as a control end condition for preventing chattering.

As described above, in the present embodiment, the squat control is terminated and returned to the predetermined damping force level even during the squat control in the middle and high speed range, so that unnecessary squat control in the middle and high speed range is performed. Can be prohibited and the ride comfort can be improved.

Note that the following conditions may be added as the above control termination conditions. The state in which the engine rotational acceleration is less than a predetermined value (for example, 2400 rpm / s) is maintained for a predetermined time (for example, 0.6
sec) Continued.

Although the present embodiment is directed to a shock absorber in which the damping force is simply set to two levels of software and hardware, the present invention is not limited to this. For example, a normal auto mode may be selected according to the driver's preference. Alternatively, in a shock absorber provided with two types of modes in which the sports auto mode can be selected, when the normal auto mode is selected, the hard is used during the squat control, and when the squat control is not performed, the software is used. When it is selected, sports can be enjoyed as hard during squat control, and as medium soft when not under control.

Next, an eleventh embodiment will be described. In the present embodiment, dive and squat control using a road surface unevenness state (bad road) estimation signal is performed. That is, the present embodiment is characterized in that in the dive / squat control, the threshold value for the dive / squat determination is corrected by the road surface state signal.

For this purpose, in this embodiment, a throttle opening switch for detecting whether the throttle is open,
A stop switch for detecting whether or not the brake petal is stepped on is provided.

Hereinafter, the control in this embodiment will be described with reference to FIG.
This will be described using a flowchart. First, step 111
Wheel speed V at 0_WPerform a process to capture Soshi
Then, in step 1120,
Wheel speed V _WEstimated vehicle speed V_BIs calculated
Put out. As a specific calculation method, the four wheel speeds
Estimate the maximum vehicle speed V_BAnd Also, consider turning.
Considering the average of the left and right wheel speeds,_BGood
No. Further, the estimated vehicle speed V_BBased on the front-back direction
Acceleration dV_BIs calculated.

[0111] At step 1130, a band-pass filter 1～2H _Z is the resonance frequency of the sprung (B. P.
F) processing by amplifying the speed signal filtered with applied to the wheel speed V _W taken in step 1110 to calculate the on vibration estimation signal V _US spring. The calculated sprung vibration estimation signal _VUS is as shown in FIG. In step 1140, by determining the time rate of change of captured wheel velocity V _W in step 1110, it calculates the wheel acceleration dV _w. In step 1150, along with performing the low-pass filtering of 10~15H near large 20H _Z than _Z is the resonance frequency component of the unsprung the wheel acceleration dV _W signal, amplifies the acceleration signal filtering filter wheel acceleration dV to calculate the _a. The calculated filtered wheel acceleration dV _a is as shown in FIG. In step 1160,
By subjecting the filtered wheel acceleration dV _a signal to full-wave rectification, the filtered wheel acceleration velocity absolute value dV _b
To calculate a predetermined time constant in the filter wheel acceleration absolute value dV _b (e.g., about 0.5 sec)
Calculating a road surface condition signal dV _sp by smoothing the filtered wheel acceleration absolute value dV _b by filtering. Filtering the wheel acceleration absolute value dV _b is 23
(D), the road surface state signal dV _SP is as shown in FIG.

In steps 1110 to 1160, the wheel speed V _W , the estimated vehicle speed V _B , and the longitudinal acceleration dV _B
When the sprung vibration estimation signal V _US , the wheel acceleration dV _W , the filtered wheel acceleration dV _a , the filtered wheel acceleration absolute value dV, and the road surface state signal dV _SP are obtained, step 11 is executed.
Go to below 70.

In step 1170, the throttle opening determination THR is fetched from the throttle opening switch, and the stop switch signal STP is fetched from the stop switch. Thereafter, the process proceeds to step 1180, where the road surface state signal dV _SP is compared with a threshold value to determine the road surface unevenness state. Step 1180 will be described in detail. As shown in FIG. 24, when the road surface state signal dV _SP <the threshold value L3, the vibration component of the unsprung resonance frequency is small, and the road surface is determined to be a good road without unevenness. Let the level x = a. Threshold L
When 3 ≦ road surface state signal dV _SP ≦ threshold value L4, the road is determined to be a normal road, and the road surface determination level x = b. When the road surface state signal dV _SP > the threshold value L4, it is determined that the road is bad, and the road surface determination level x is set to x = c. In order to prevent chattering, after a predetermined time t4 has elapsed since the road surface state signal dV _SP <threshold value L4 ′, the road surface determination level x becomes c.
To b. Further, after a predetermined time t3 has elapsed since the road surface state signal dV _SP <threshold value L3 ′, the road surface determination determination level changes from b to a.

In step 1190, the dive determination basic levels 1DC and 1DB for correcting the threshold values L9 and L10 are corrected from the map shown in FIG. 25, and the threshold values L11 and L12 are corrected from the map shown in FIG. Squat judgment basic levels 1SC and 1SD for the calculation. Figures 25 and 26
As is apparent from, 1DC, 1DB, 1SC, 1SD is made to change according to the estimated vehicle speed V _B.

In step 1200, dive determination correction coefficients KDC and KDB for correcting threshold values L9 and L10 are obtained from the map shown in FIG.
Squat determination correction coefficients KSC and KSD for correcting the threshold values L11 and L12 are calculated. As apparent from FIG. 27,28, KDC, KDB, KSC, KSD is made to change according to the road surface condition signal dV _SP.

In step 1210, step 1190
And the determination basic levels 1DC, 1DB, 1SC, 1SD and the correction coefficients KDC, KDB,
The threshold values L9 to L12 are corrected from KSC and KSD by the following equation.

[0117]

## EQU10 ## L9 = 1DB × KDB

[0118]

L10 = 1DC × KDC

[0119]

L11 = 1SD × KSD

[0120]

L12 = 1 SC × KSC In step 1220, the dive of the vehicle in the posture change state of the vehicle is determined by turning on / off the stop switch signal STP and comparing the longitudinal acceleration dV _B with a threshold value. I do. Step 1220 will be described in detail. As shown in FIG.
Is off, or when the longitudinal acceleration dV _B > the threshold value L9, it is determined that the load is not moving to the front part of the vehicle, and the posture change determination level Y = G. When the stop switch signal STP is on and the threshold value L10 ≦ the longitudinal acceleration dV _B ≦ the threshold value L9, it is determined that the load is slightly moving to the front part of the vehicle due to gentle braking. And the posture change determination level Y = H. When the stop switch signal STP is on and the longitudinal acceleration dV _B <the threshold value L10, it is determined that a considerable load is moving to the front of the vehicle due to sudden braking, and the posture change determination level is determined. Let Y = I.

At step 1230, the throttle opening degree is determined.
ON / OFF of constant THR and longitudinal acceleration dV_BThreshold
By comparing with the value, the vehicle
Determine both quotes. Step 1230 in detail
To explain, as shown in FIG.
When THR is off or longitudinal acceleration dV _B
<When the threshold value is L11, the load moves to the rear of the vehicle.
It is determined that it has not been performed, and the posture change determination level Y is set to G.
Throttle opening determination THR is on, and threshold
Value L11 ≦ longitudinal acceleration dV_B≤ threshold L12
At this time, there is a slight load on the rear of the vehicle due to slow acceleration. When
It is determined that the posture change determination level is Y = H. slot
The opening degree judgment THR is on and the longitudinal acceleration
dV_B> When the threshold value is L12, the rear of the vehicle
Judge that the load is moving considerably,
It is assumed that the constant level Y = I.

If the attitude change state of the vehicle is determined in steps 1220 and 1230, step 124 is executed.
Go to 0. In step 1240, steps 1230,
The posture change determination levels Y at 1240 are compared, and the one with the highest level is set as the maximum posture change determination level Y ′. However, the magnitude of the level is G <H <I
It has become. For example, in step 1220, the posture change determination level Y = G, in step 1230, the posture change determination level Y = I, and the maximum posture change determination level Y '= I. If the unevenness of the road surface and the posture change state of the vehicle can be determined in steps 1180 and 1240, the optimal damping of the shock absorber is performed in step 1250 based on the road surface determination level x and the maximum value Y ′ of the posture change determination level. Set the force. In this step 1250, the damping force is determined with reference to the map shown in FIG. Explaining the map shown in FIG. 31, when the vehicle is changing posture on a good road or a normal road, the damping force is set to hard, but when the vehicle is changing posture on a bad road, the damping force is set. Set to medium. As a result, it is possible to prevent a change in posture and maintain an optimal vehicle posture while reducing the rugged feeling due to unevenness of the road surface. For example, in step 1240, the maximum value of the posture change determination level Y '= I, step 11
If the road surface determination level x = b at 80, the damping force of the shock absorber is set to hard.

When the damping force of the shock absorber is set in step 1250, the process returns to step 1110. It should be noted that the characteristics of the map shown in FIG. 31 are merely examples, and maps having various characteristics other than the above-described map can be adopted.

As described above, in the eleventh embodiment, the
Road surface state signal dV according to the underside information _SPFrom the correction coefficient KD
C, KDB, KSC, and KSD are calculated, and these correction coefficients KDC,
Correction of threshold values L9 to L12 using KDB, KSC, KSD
doing. Correction coefficients KDC, KDB, KSC, KSD are road surface conditions
State signal dV_SPThe larger the
When traveling on a rough road, the threshold values L9 to L12 are
It is corrected to be larger.

Therefore, even when the posture of the vehicle has changed, the signal indicating the posture of the vehicle is unlikely to exceed the threshold value when the vehicle is traveling on a rough road, and the damping force is hardly set to a hard value. In addition, it is possible to maintain the optimum vehicle posture while reducing the rugged feeling due to the unevenness of the road surface.

In this embodiment, the threshold value to be determined is corrected by the road surface condition signal. On the contrary, a signal for detecting the dive and squat state of the vehicle (for example, the longitudinal acceleration d
V _B , its change amount, the engine rotational acceleration dNe, and its change amount, throttle opening θ, its change amount Δθ, etc.) so that the signal strength becomes smaller as the road surface state signal becomes larger (rough road). Performing such as correction, etc.,
Similar effects may be obtained.

Next, a twelfth embodiment will be described. In the fourth embodiment, anti-dive control in which the damping force is switched to a higher level (hard) is performed every time the level of the stop switch signal STP changes. However, in the present embodiment, the above control is performed only in a high vehicle speed range and the low vehicle speed is reduced. In the range, the dive state of the vehicle is detected on the basis of the variation ΔG _BF of the vehicle body acceleration, and the damping force is increased (hard) only when it is determined that the dive state is necessary from the magnitude of the dive state.
It is characterized by eliminating unnecessary increase in damping force by changing the level of the vehicle, and improving riding comfort on rough road surface during braking.

Hereinafter, a fourth embodiment (FIG. 12) will be described with reference to FIG.
The explanation focuses on the differences from Steps 600 to 600 in FIG.
630, similar to steps 600 to 630 in FIG.
And the above ΔG_BFCalculation and STP signal capture
And in step 640,
From the average value of the wheel speeds of the left and right wheels, _BFCalculate
You. This level change of the STP signal and ΔG_BFAttenuation based on
Step A corresponding to force switching determination I (hereinafter, control I)
700 and damping force switching judgment II (hereinafter referred to as control II).
Step A800 and the damping force switching (Step A
910, A920).

In step A710, it is determined whether or not the above control I is being performed. If it is determined that the control I is not being performed, the process proceeds to step A720 to determine whether the following control I condition is satisfied.

Control I condition: The vehicle speed is 60 km / h or more when STP is turned from OFF to ON. Step A9 when it is determined that the above control I condition is satisfied
Proceed to 20 to switch the damping force to hardware.

In the step A720, the control I
If it is determined that the condition is not satisfied, the process proceeds to step A810 to determine whether the control II is being performed. When it is determined that the control II is not being performed, the process proceeds to step 820, and it is determined whether the following control II condition is satisfied.

Control II condition: STP = ON and | Δ
G _BF | ≧ predetermined value (for example, 0.035 G / 32 ms) Depending on whether or not the above control II condition is satisfied, step A
Proceeding to step 920 or step A910, a command value signal for making the damping force hard or soft is output, and this routine ends.

In step A710, control I
If it is determined that it is in the middle, the process proceeds to step A730, and it is determined whether or not the following control I termination condition is satisfied. Control I end condition: A predetermined time (for example, 0.5 S) has elapsed after the control I condition was satisfied.

If it is determined that the control end condition is not satisfied, the process proceeds to step A920, and the damping force is kept hard. If it is determined that the control I end condition is satisfied, the process proceeds to step A810.

If it is determined in step A810 that the control II is being performed, the flow advances to step A830 to determine whether or not the following control II termination condition is satisfied. Control II termination condition: | ΔG _BF | <predetermined value (for example, 0.
02G / 32 ms) for a predetermined time (for example, for 1 s).

The process proceeds to step A910 or step A920 depending on whether or not the control II end condition is satisfied, and outputs a command value signal for making the damping force soft or hard.

Next, a thirteenth embodiment will be described. In the first to twelfth embodiments, the dive and squat generated by the action intended by the driver (stepping on the brake or the throttle) are controlled. It controls dives and squats caused by disturbances. That is, the present embodiment is characterized in that when the vehicle is subjected to disturbance, the air resistance apparently increases and the vehicle speed decreases, and the decrease in the vehicle speed is detected from the wheel speed signal.

Specifically, the change ΔG _{BF of the} vehicle body acceleration is calculated in the same manner as in the first embodiment, and the damping force is hardly set by comparing the change ΔG _BF of the vehicle body acceleration with a reference value. Since the dives and squats generated at this time are usually smaller than the dives and squats generated when the brake accelerator is actuated, if the shock absorber is capable of setting the damping force in multiple stages, it is necessary to use software. The return may be performed in the same manner as in the first embodiment.

In the first embodiment, the change ΔGBF of the vehicle body acceleration within a predetermined time or the engine rotational acceleration ΔdNe is calculated and used for control.
It goes without saying that the same control may be performed by calculating the differential value of the BF or the differential value of the engine rotational acceleration dNe.

Further, since the noise component is large in the raw vehicle acceleration calculated as the differential value of the vehicle speed V _BF (the amount of change within a predetermined time), the frequency component necessary for estimating the longitudinal behavior of the vehicle is calculated. predetermined cutoff frequency for extracting (e.g., 3H _Z) calculates those subjected to low-pass filter of the body acceleration of the raw as vehicle acceleration G _BF, are further variation within a predetermined time than the G _BF body it may be calculated the variation .DELTA.G _BF acceleration.

In the above-described embodiment, a large number of reference values may be set to finely switch the damping force. As a result, the switching shock is reduced and the control can be started earlier, so that the posture change can be suppressed more effectively.

[0142]

As described above, according to the damping force variable shock absorber control device of the first aspect, the change in the vehicle body acceleration is calculated using the signal from the wheel speed sensor, and the change in the vehicle body acceleration is calculated. Since the damping force of the shock absorber is adjusted based on the minute, it is possible to calculate the amount of change in the vehicle body acceleration without using an acceleration sensor, and it is possible to suppress changes in posture such as nose dive and squat with good responsiveness. This has the effect.

According to the damping force variable shock absorber control device of the second aspect, the damping force of the shock absorber is adjusted based on the change in the rotational acceleration of the engine. There is an effect that a change in posture can be suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control procedure according to the first embodiment.

FIG. 3 is a waveform diagram illustrating the operation of the first embodiment.

FIG. 4 is a waveform chart for explaining the operation of the second embodiment of the present invention.

FIG. 5 is a waveform diagram illustrating the operation of the second embodiment.

FIG. 6 is a configuration diagram illustrating a configuration of a second embodiment.

FIG. 7 is a flowchart illustrating a control procedure according to a second embodiment.

FIG. 8 is a waveform chart for explaining the operation of the third embodiment of the present invention.

FIG. 9 is a flowchart illustrating a control procedure according to the third embodiment.

FIG. 10 is a configuration diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 11 is a waveform diagram illustrating the operation of the fourth embodiment.

FIG. 12 is a flowchart illustrating a control procedure according to a fourth embodiment.

FIG. 13 is a characteristic diagram illustrating the operation of the fifth embodiment of the present invention.

FIG. 14 is a flowchart illustrating a control procedure according to a fifth embodiment.

FIG. 15 is a characteristic diagram showing another example of the fifth example.

FIG. 16 is a configuration diagram showing a configuration of a sixth embodiment of the present invention.

FIG. 17 is a flowchart illustrating a control procedure according to a sixth embodiment.

FIG. 18 is a flowchart illustrating a control procedure according to a seventh embodiment.

FIG. 19 is a flowchart showing a control procedure according to the eighth embodiment.

FIG. 20 is a flowchart illustrating a control procedure according to a ninth embodiment.

FIG. 21 is a flowchart illustrating a control procedure according to the tenth embodiment.

FIG. 22 is a flowchart illustrating a control procedure according to the eleventh embodiment.

FIG. 23 is an explanatory diagram for explaining the operation of the eleventh embodiment.

FIG. 24 is a characteristic diagram illustrating a relationship between a road surface state signal dV _SP and a road surface determination level x.

FIG. 25: Estimated vehicle speed V _B and dive determination reference level 1
Shows the relationship between DC and IDB

[Figure 26] estimated vehicle speed V _B and the squat criterion level LSC, a map showing the relationship between LSD.

FIG. 27 shows a road surface state signal dV _SP and a dive judgment correction coefficient K
9 is a map showing a relationship between DC and KDB.

FIG. 28 is a map showing a relationship between a road surface state signal dV _SP and squat determination correction coefficients KSC and KSB.

29 is a characteristic diagram showing the relationship of the stop switch signal STP and longitudinal acceleration dV _B and attitude change judgment level Y.

FIG. 30 is a characteristic diagram showing the relationship between the throttle opening determination THR and longitudinal acceleration dV _B and attitude change judgment level Y.

FIG. 31 is a map for setting a damping force from a posture determination level Y and a road surface determination level x.

FIG. 32 is a flowchart showing a control procedure according to the twelfth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic control apparatus 2 Vehicle speed sensor 3 Engine speed sensor 4 Input buffer 5 Input buffer 6 Shock absorber 10 Drive circuit

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinya Takemoto 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (72) Mikio Tanabe 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Nihon Denso Co., Ltd. (56) References JP-A-60-244610 (JP, A) JP-A-58-131442 (JP, A) JP-A-58-141909 (JP, A) JP-A-62-64606 (JP, A) JP-A-2-182529 (JP, A) JP-A-60-116515 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60G 17/015

Claims (2)

(57) [Claims] 1. A a wheel speed sensor for detecting a wheel speed, greater circumferential than the resonance frequency of the vehicle body among the frequency components included in the detected wheel speed signal by said wheel speed sensors
Removing means for removing a wave number component; and a frequency component lower than a resonance frequency of the vehicle body by the removing means.
Based on the wheel speed signal determined only by the minute, a predetermined arithmetic expression
A vehicle body acceleration calculating means for calculating the vehicle longitudinal acceleration at the vehicle body front-rear pressure calculated by the vehicle body acceleration calculating means
A change amount calculating means for calculating the change amount of the vehicle body acceleration based on the speed; and a control signal for adjusting the damping force of the shock absorber based on the change amount of the vehicle body acceleration calculated by the change amount calculating means. And a control means for adjusting a damping force of the shock absorber according to a control signal from the control means. 2. An engine speed detecting means for detecting an engine speed, an engine speed calculating device for calculating an engine speed from the engine speed, and a change in the engine speed from the engine speed. A damping force variable shock absorber control device, comprising: a change amount calculating means for adjusting the damping force of the shock absorber based on the change amount of the engine rotational acceleration.