JPH05345510A - Damping force variable shock absorber controller - Google Patents

Abstract

PURPOSE:To provide damping control in compliance with the posture change such as nose-dive and squat positively by calculating the changing component of a signal corresponding to the acceleration/deceleration of a vehicle, and controlling the damping force of a shock absorber according to the changing component. CONSTITUTION:This damping force variable shock absorber controller is provided with a microcomputer 1, and performs prescribed calculation. This shock absorber controller is also provided with a wheel speed sensor 2, and removes frequency component higher than the approximate resonant frequency of a vehicle body from the frequency component included in a detected wheel speed signal, and calculates the acceleration of the vehicle body and based on a prescribed calculation formula from the removed wheel speed signal to calculate the changing component of the vehicle body acceleration from the vehicle body acceleration from the body acceleration. A control signal is outputted so as to regulate the damping force of a shock absorber 6 based on the changing component of the vehicle body acceleration, and based on the control signal, the damping force of the shock absorber 6 is regulated according to the control signal.

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 for suppressing a squat and a nose dive generated when a vehicle is accelerated or decelerated by adjusting a damping force of a shock absorber.

[0002]

2. Description of the Related Art Conventionally, for example, in Japanese Examined Patent Publication No. 63-63401, 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. It is disclosed to suppress dive. Further, in JP-A-60-47717, engine rotational acceleration is calculated from the rotational speed of the engine, and when the acceleration exceeds a reference value, the damping force of the shock absorber is increased to suppress vehicle squat. It is disclosed.

[0003]

Here, since the damping force of the shock absorber works to suppress the change in the posture of the vehicle body, it is possible to increase the damping force by appropriately responding to the state in which the posture of the vehicle body changes. 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 corresponds to the posture change of the nose dive, squat and the like. It is difficult to control.

This is because it has been clarified by the study of the present inventors that the attitude change such as nose dive and squat occurs in the vehicle 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. 61-150809 and Japanese Utility Model Laid-Open No. 3-1807, an acceleration sensor is attached to a vehicle body, and a change amount of the vehicle body acceleration is detected from a 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 change in posture such as a nose dive or squat based on the calculated change in acceleration.

However, the above-mentioned conventional apparatus has a problem that the control response delay is large because the signal from the acceleration sensor is used to detect the change in acceleration. In other words, since the nose dive and squat are changes in the posture of the vehicle body after changes in the engine speed and wheel speeds, the vehicle body with the acceleration as in the device of the above publication is completely When acceleration is detected and control is started for the first time after a large posture change occurs, it may mean 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 or the like having an anti-skid control device, the number of vehicles of which has been increasing in recent years, is equipped with a wheel speed sensor. It has been found that by using the signal, the change in the vehicle body acceleration can be detected without using the acceleration sensor as in the conventional case.

Therefore, according to the present invention, a change in vehicle body acceleration is accurately detected by using a wheel speed sensor, and the damping force of a shock absorber is adjusted according to the change in acceleration to change the posture of a nose dive, squat, or the like. A first object of the present invention is to provide a suspension control device that prevents the above-mentioned problems.

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 according to the change to prevent posture changes such as nose dive and squat. This is the second purpose.

[0011]

In order to achieve the above object, a first damping force variable shock absorber control device of the present invention detects a wheel speed by a wheel speed sensor and the wheel speed sensor. Based on a predetermined arithmetic expression from the removing means for removing frequency components near the resonance frequency of the vehicle body out of the frequency components included in the wheel speed signal, and the wheel speed signal from which frequency components near the resonance frequency of the vehicle body are removed. Vehicle body acceleration calculating means for calculating vehicle body acceleration,
Change amount calculating means for calculating a change amount of the vehicle body acceleration from the vehicle body acceleration; control means for outputting a control signal so as to adjust the damping force of the shock absorber based on the change amount of the wheel acceleration; and the control means. Adjusting means for adjusting the damping force of the shock absorber in accordance with the control signal of 1.

Further, the first damping force variable shock absorber control device of the present invention is the engine speed detecting means for detecting the engine speed, and the engine speed acceleration calculating means for calculating the engine speed acceleration from the engine speed. A change amount calculating means for calculating a change amount of the engine rotation acceleration from the engine rotation acceleration, and a control means for outputting a control signal so as to adjust the damping force of the shock absorber based on the change amount of the engine rotation acceleration. Adjusting means for adjusting the damping force of the shock absorber according to a control signal from the control means.

[0013]

With the above construction, the damping force variable shock absorber control device according to the first aspect removes the frequency component above the resonance frequency of the vehicle body among the frequency components included in the wheel speed signal from the wheel speed sensor. The vehicle body acceleration is calculated from the wheel speed signal from which the frequency components above the resonance frequency of the vehicle body have been removed, based on a predetermined arithmetic expression.

Here, the reason why the frequency components above the resonance frequency of the vehicle body are 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 (sprung resonance frequency) and unsprung resonance frequency of the vehicle body. As described above, according to the invention of the present application, the posture change of the vehicle body is suppressed. Therefore, when the component other than the component near the resonance frequency of the vehicle body is included, it may not be possible to accurately determine the posture change of the vehicle body. .. Therefore, the removing unit removes the components other than the components near the resonance frequency of the vehicle body, and extracts only the components near the resonance frequency of the vehicle body to be used for control.

By calculating the change amount of the acceleration from the vehicle body acceleration, the change amount of the vehicle body acceleration can be accurately detected, and when the posture change to be actually suppressed occurs in the vehicle, the shock absorber is based on this. The damping force of can be adjusted.

Further, with the above configuration, the damping force variable shock absorber control device according to the second aspect adjusts the damping force of the shock absorber based on the amount of change in the engine speed, so that there is a change in the posture that should be actually suppressed. The damping force of the shock absorber can be adjusted as it occurs in the vehicle.

[0017]

[Embodiment] 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
Is composed of a CPU 1-1, a ROM 1-2, a RAM 1-3, etc., and executes predetermined arithmetic processing. The wheel speed sensor 2 corresponds 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 according to the rotation speed of each wheel. The wheel speed sensors 2 may of course be provided on 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 waveform-shapes and amplifies the signal generated by the wheel speed sensor 2 and outputs it to the ECU 1.

The shock absorbers 6 to 9 are provided between the vehicle body and the wheels corresponding to the four wheels of the vehicle, and the generated damping force can be changed. The drive circuits 10 to 13 adjust the generated damping force of the shock absorbers 6 to 9 according to the control signal from the ECU 1. Also,
Reference numeral 14 is 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 flow chart showing the contents of processing executed by the ECU 1. Further, 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, Vr of the left and right wheels are calculated based on the signals output from the wheel speed sensor 2. The wheel velocities Vl and Vr increase / decrease as shown in FIG. 3, for example, 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 (cut-off frequency 3 Hz) is determined as the vehicle body speed VBF. .. By this low-pass filter processing, only the resonance frequency component on the spring is extracted from the various frequency components included in the wheel speed. That is, the wheel speed signal fluctuation based on the attitude change of the vehicle body is extracted. And this vehicle speed VBF
Based on, the vehicle body acceleration GBF is calculated from 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, the change amount ΔGBF of the vehicle body acceleration GBF calculated in step 110 within a predetermined time is calculated by the following equation.

[0023]

## EQU00002 ## .DELTA.GBF (i) = GBF (i) -GBF (i-1) Then, based on the change .DELTA.GBF of the vehicle body acceleration, the magnitude of the damping force of the shock absorbers 6-9 is set to two levels (software, A process 200 for outputting a command signal for switching to (hard) is executed.

The command signal output process 200 will be described. First, in step 210, it is determined whether the damping force has already been switched to hard. If not switched to hardware, proceed to step 220,
It is determined whether the conditions for switching to the hardware have been satisfied. The hardware switching conditions are as shown below.

[0025]

[Equation 3] Anti-squat control ΔGBF ≧ k _SH1 Anti-dive control ΔGBF <k _DH1 That is, as shown in FIG.
Is harder than the switching reference value k _SH1 for the anti-squat control or becomes smaller than the switching reference value k _DH1 for the anti-dive control. It should be noted that the actual switching of the damping force may be performed when the above conditions are satisfied a plurality of times in succession.

If it is determined in step 220 that the change ΔGBF in vehicle body acceleration is smaller than the squat switching reference value k _{SH 1} or is greater than or equal to the dive switching reference value k _DH1 , the process proceeds to step 240 to reduce the damping force. A command signal for softening is output and this routine ends. On the other hand, if it is determined that the change amount 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 damping force is commanded to be hard. A signal is output and this routine ends.

If it is determined in step 210 that the damping force is switched to hard, the process proceeds to step 230, and it is determined whether or not the conditions for returning to software in anti-squat control or anti-dive control are satisfied. To do. This soft recovery condition is as shown below.

[0028]

[Equation 4] Anti-squat control ΔGBF <k _SH2 Anti-dive control ΔGBF ≧ k _DH2 That is, during anti-squat control, when the change ΔGBF in vehicle body acceleration becomes smaller than the squat return reference value k _SH2 , during anti-dive control, The damping force is softly switched when the dive return reference value k _SH2 or more is reached. 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. ). Change in vehicle acceleration ΔGBF is the squat return reference value k
_{When the} time when it becomes smaller than _SH2 (when it becomes the dive return reference value k _DH2 or more) continues for the predetermined time Td, the damping force is softly switched.

By adding conditions such as the above, the damping force can be softly switched when the magnitude of the change amount ΔGBF of 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 longer as the vehicle speed increases or becomes longer as the peak value of the change ΔGBF of the vehicle body acceleration increases. It may be variable.

Next, a second embodiment of the present invention will be described. In the above-mentioned first embodiment, the change amount ΔGBF of the vehicle body acceleration
Although the anti-squart control and the anti-dive control are performed based on the above, in the second embodiment, the anti-squat control and the anti-dive control are performed based on the change amount ΔdNe of the engine rotation acceleration dNe.

Particularly in a vehicle equipped with a manual transmission,
The engine rotation speed Ne increases almost in the same manner as the vehicle speed increases. Therefore, the engine rotation acceleration dNe is
It can be regarded as a signal corresponding to the acceleration of the vehicle. Moreover, when anti-squat control is performed by using the change amount ΔdNe of the engine rotation acceleration instead of the change amount ΔGBF of the vehicle body acceleration, it is possible to more quickly detect the posture change (squat) of the vehicle and increase the damping force. There is.

That is, as shown in FIG. 4, when the driver starts the accelerator operation and the throttle valve of the engine is opened, first, the intake pipe pressure Pm of the engine rises and the engine speed Ne is slightly delayed. To rise. The drive torque generated by the engine begins to increase 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 vehicle attitude change and the driving torque T when a squat occurs will be described. If the squat force Ws is the force that produces squat in the vehicle, the distance from the center of gravity of the vehicle body to the driving wheels is 1, the distance from the center of gravity of the vehicle body to the road surface is h, and the inertia of the driving wheels is I,
The squat force Ws is calculated by the following equation.

[0034]

## EQU00005 ## Ws = h.times. (T-I.times.d.omega.) / L That is, the squat force Ws is the driving torque T minus the force required to rotate the driving wheel having inertia I (T-I.times. proportional to dω). Therefore, in order to appropriately prevent squat, it is desirable to increase the damping force when the drive torque starts to increase.

FIG. 5 shows the relationship among the driving torque T, the squat force Ws, and the driving wheel speed Vω. As is apparent from FIG. 5, the squat force Ws also rises as the driving torque T rises, and thereafter both change substantially in the same manner. On the other hand, the drive wheel speed Vω starts to increase with a slight delay (about 0.1 seconds) from the increase of the drive torque T and the squat force Ws.

Therefore, if the anti-squat control is performed based on the change amount 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 change of the attitude of the vehicle. However, as described above, the engine speed Ne starts to increase almost at the same time as the driving torque T. Therefore, if the anti-squat control is performed using the change amount ΔdNe of the engine rotation acceleration based on the engine speed Ne, the delay is delayed. Can be reduced.

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

FIG. 7 is a flow chart 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 from the following equation.
Calculate e.

[0039]

## EQU6 ## 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 of the engine rotational acceleration dNe within a predetermined time is calculated from the following equation.
Calculate e.

[0041]

## EQU00007 ## .DELTA.dNe (i) =. DELTA.dNe (i)-. DELTA.dNe (i-1) In step 330, the amount of change .DELTA.dNe in the engine rotational acceleration dNe calculated in step 320 within a predetermined time period.
Based on, the damping force switching command signal output processing is executed. This process is basically the command signal output process 20 of the first embodiment.
It is the same as 0, and only the hardware switching condition and the soft recovery condition are slightly different.

The hardware switching conditions in the second embodiment are as shown in the following equation.

[0043]

[Formula 8] 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.

A vehicle speed condition may be added to the above hardware switching condition. That is, for example, the vehicle speed is 20k
Only when in the low vehicle speed range of m / h or less, the above-mentioned hardware switching condition is determined and the damping force is switched. This is based on the fact that squats are almost always generated in the vehicle when the vehicle accelerates rapidly from the low vehicle speed range, and squarts are rarely generated in the medium and high speed ranges. And by further limiting the conditions for switching the damping force to hard by anti-squat control,
The frequency of switching to hardware can be reduced to improve the riding comfort.

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

[0046]

Respect Equation 9] ΔdNe <k _SH4 this return condition, as described in the first embodiment can be further added to the condition by its duration and level of the return reference value k _SH4.

As described above, the squat control by the change amount ΔdNe of the engine rotation 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, the engine speed and the vehicle speed may not correspond accurately due to the action of the torque converter existing between the engine and the drive wheels. This is because slippage occurs in the torque converter especially when the engine speed rapidly increases. However, if this phenomenon is used conversely, it becomes possible to more easily detect the occurrence of a vehicle squat.

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

As the processing in the ECU 1 in this case, 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 content in the ECU 1 can be simplified. As described above, the anti-quote control is performed when the engine rotation acceleration dNe or the variation ΔdNe thereof is a positive predetermined value or more, but conversely, when the engine rotation acceleration dNe is a negative predetermined value or less, engine braking may be determined and 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 change amount ΔGBF of the vehicle body acceleration, and in the second embodiment, the anti-squat control is performed based on the change amount ΔdNe of the engine rotation acceleration dNe. I explained.

In the third embodiment, the anti-squat control is performed by combining the first embodiment and the second embodiment. In this case, as shown in FIG. 8, the start of the anti-squat control is mainly defined by the change amount ΔdNe of the engine rotation acceleration dNe, and the end thereof is mainly specified by the change amount ΔGBF of the vehicle body acceleration. If the change amount 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 more quickly detect the posture change (squart) of the vehicle to increase the damping force of the shock absorber, and to prevent the posture change of the vehicle body in the state where the damping force is increased. It can be reliably maintained until the point when it is needed.

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

FIG. 9 shows the processing contents of the ECU 1 in the third embodiment. In FIG. 9, in step 400, the wheel speed, in step 410, the vehicle body acceleration, and in step 4
At 20, the change amount ΔGBF of the vehicle body acceleration is calculated. Further, in step 430, the engine speed is changed to 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 amount ΔGBF of these vehicle body accelerations
And based on the change ΔdNe of the engine rotation acceleration,
A process 500 for outputting a command signal for switching the magnitude of the damping force of the shock absorbers 6 to 9 between two levels (software and hardware) is executed.

At step 510, it is judged whether the damping force has already been switched to hardware, and if it has not been switched to hardware, the routine proceeds to step 520. In step 520, the change amount ΔdNe of the engine rotation acceleration is calculated.
Is greater than or equal to the switching reference value k _SH3, and in step 530, the change amount ΔGBF of the vehicle body acceleration is equal to the switching reference value k SH.
Determine whether or not it has exceeded _SH1 . Then, in the determinations in steps 520 and 530, if any one of them is satisfied, the process proceeds to step 580, and the damping force is switched to hardware. On the other hand, when neither of the conditions of steps 520 and 530 is satisfied, the routine proceeds to step 540, where the damping force is softened.

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

As described above, the start of the anti-squat control is mainly due to the change Δ in the engine rotation acceleration dNe.
It is defined by dNe, and the end thereof is mainly defined by the change amount ΔGBF of the vehicle body acceleration. Therefore, as the 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 the 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 second and third embodiments, the anti-squat control is performed based on the change amount ΔdNe of the engine rotation acceleration dNe. However, the change amount ΔdNe of the engine rotation acceleration dNe is changed to the anti-squat control. 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 increase in the intake pipe pressure Pm of the engine and the increase in the engine speed Ne are related, and the intake pipe pressure Pm increases 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 of 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 above-described third embodiment, the amount of change in vehicle body acceleration ΔGBF
And the variation ΔdNe of the engine rotation acceleration dNe were combined to perform the anti-squat control.
In the embodiment, anti-dive control is performed by combining the change amount 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, the 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 variation ΔG of the vehicle body acceleration.
Since the anti-dive control is performed using the signal from the stop switch 15 in addition to the BF, the anti-dive control with excellent responsiveness can be performed. That is,
As shown in FIG. 11, since the damping force can be immediately increased at the start of braking or at the end of braking, it is possible to reliably prevent a change in posture of the vehicle (dive and return from dive) that occurs thereafter.

FIG. 12 shows the processing contents executed by the ECU 1 in the fourth embodiment. In FIG. 12, step 6
From the processing from 00 to step 620, the above-mentioned first
Similar to the embodiment, the change amount ΔGBF of the vehicle body acceleration is calculated. In step 630, the stop switch signal is fetched and it is detected whether or not the level has changed from the previously fetched stop switch signal.

The damping force switching command signal output process 700 is executed based on the level change of the stop switch signal and the change amount ΔGBF of the vehicle body acceleration. In this command signal output processing 700, first, at step 710, it is determined whether the damping force has already been switched to hard. 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 to switch the damping force to hard. On the other hand, if there is no level change, the routine proceeds to step 730, where it is determined based on the change ΔGBF of the vehicle body acceleration whether or not the condition for switching the damping force to the hard condition is satisfied. Step 7 again
The processing in 50 and 760 is to determine the return of the damping force to the software based on the change amount ΔGBF of the vehicle body acceleration, and is the same as 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 then the damping force is switched to soft according to the change ΔGBF of the vehicle body acceleration. , Responsive,
In addition, it becomes possible to perform anti-dive control that accurately responds to changes 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 vehicle speed is 6%.
It may be executed only when it is 0 km / h or more. This is because when the driver brakes at high speed, there is a high possibility that a large attitude change (dive) will occur (for example, there are many cases of sudden braking).

Further, when the anti-dive control is started, it may be determined only by the level change of the stop switch signal. In this case, step 7 of the flowchart in FIG.
The processing of 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 change amount ΔGBF of the vehicle body acceleration are calculated in the same manner as in the first embodiment, and both are combined to perform anti-squat control and anti-dive control. The fifth embodiment will be described by taking anti-squat control as an example.

That is, as shown in FIG. 13, the hardware switching reference value k for comparison with the change amount ΔGBF of the vehicle body acceleration.
₀ and the soft return reference value k ₁ are set based on the vehicle body acceleration GBF. As is clear from FIG. 13, the relationship between the hard switching reference value k ₀ and the soft recovery reference value k ₁ and the vehicle body acceleration GBF is such that as the vehicle body acceleration GBF increases, the hard switching reference value k ₀ and the soft recovery reference value are increased. The map is set so that k ₁ becomes small. For this reason, as the vehicle body acceleration GBF increases, the damping force can be easily switched to a harder state, a small attitude change of the vehicle can be suppressed, and the traveling stability of the vehicle improves.

FIG. 14 is a flow chart showing the processing contents executed by the ECU 1 in the fifth embodiment. In addition,
Since this flowchart is the same as the flowchart shown in FIG. 2 in the processing until the change ΔGBF of the vehicle body acceleration is calculated, that processing is omitted.

Referring to FIG. 14, in step 800, the switching reference value k ₀ and the damping force for hard switching the damping force are set on the basis of the vehicle body acceleration GBF in accordance with a preset and stored map as shown in FIG. A return reference value k ₁ for returning from hardware to software is determined. The processing from steps 810 to 860 is to switch the damping force by comparing the change amount ΔGBF of the vehicle body acceleration with the respective reference values k ₀ and k ₁ , as in the above-described first embodiment and the like.

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

Further, as shown in FIG. 15, low vehicle speed range, medium
Set up multiple maps according to vehicle speed range such as vehicle speed range and high vehicle speed range
You may set it. In this case, the vehicle speed range becomes high
The smaller the vehicle body acceleration GBF, the harder the switching reference value.
k_0,And soft recovery reference value k ₁Set to be smaller
To do. As a result, the damping force is further increased in the middle and high speed range.
Because it is easy to switch to hardware, the running stability of the vehicle
It is possible to further improve the sex.

Further, 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, but the engine rotational acceleration dNe and the engine rotational acceleration change are calculated. ΔdN
It goes without saying that the same control can be performed by calculating e and combining both.

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

For this reason, the fifth embodiment is premised on a system capable of independently adjusting the spring constant and the damping force of the suspension. An example of this system is shown in FIG. In FIG. 16, 30 to 33 are air springs having an air chamber inside, 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 air pressure according to a command signal from the ECU 1.

The processing contents executed by the ECU 1 in the fifth embodiment are shown in the flowchart of FIG. Note that this flowchart is the same as the flowchart shown in FIG. 2 in the processing until the change ΔGBF of the vehicle body acceleration is calculated, and therefore the processing is omitted.

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

In step 960, it is determined whether or not the spring constant has already been switched to hardware, and if it has not been switched to hardware, the routine proceeds to step 970. In step 970, the vehicle body acceleration GBF is the acceleration reference value F _SH1.
It is determined whether or not it has become the above, or whether it has become smaller than the deceleration reference value F _DH1 . In this determination, if either one of the conditions is satisfied, the process proceeds to step 1010 and the spring constant is switched to the hard one. On the other hand, when 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 hard, the process proceeds to step 990. In step 990, the vehicle body acceleration GBF
Is smaller than the acceleration return reference value F _SH2 , or is equal to or more than the deceleration return reference value F _DH2 . If neither condition is satisfied, step 10
Go to 10 and leave the damping force hard. On the other hand, if either condition is satisfied, step 1000
Then, it is determined whether or not a predetermined time TdG has passed since the condition was satisfied. If the predetermined time TdG has elapsed, the process proceeds to step 980 to switch the damping force to soft, and if not, the process proceeds to step 1010 to keep the damping force hard.

By such control, it is possible to suppress the fluctuation of the attitude of the vehicle body such as a dive, a squat and the like, and also to maintain the attitude in a stable state even when the attitude of the vehicle body is not actually changed. That is, it is considered that the spring forces of the air springs 30 to 33 and the vehicle body are in balance when the change ΔGBF of the vehicle body acceleration is small and the posture of the vehicle body does not change much. At this time, as the vehicle body acceleration GBF increases, each air spring 30 to
If the spring force of 33 is made strong (the spring constant is made hard), the posture of the vehicle body is stabilized at a tilt that is closer to horizontal.

In the sixth embodiment described above, the spring constant is changed by the air pressure of the air spring, but the torsional elastic force of the stabilizer may be changed according to the vehicle body acceleration GBF. As described above, since a stabilizer capable of adjusting the torsional elastic force is known, the description of its structure is omitted.

Further, in the above-mentioned first to sixth embodiments, the magnitude of the damping force is switched to two levels, but it may be switched to three or more levels.
In this case, the respective reference values are set according to the level of the magnitude of the damping force, and are compared with the magnitude of the change ΔGBF of the vehicle body acceleration and the change ΔdNe of the engine rotational acceleration, respectively. For example, in the first embodiment, when switching the magnitude of the damping force to three levels of soft, medium and hard, the squat switching reference value k _{SM1 and the} return reference value k _SM2 corresponding to medium correspond to hardware. Set to values smaller than the squat switching reference value k _{SH1 and the} return reference value k _SH2 . Then, the change amount ΔGBF of the vehicle body acceleration becomes equal to or larger than the squat switching reference value k _SM1 corresponding to the medium,
If it 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. 7th
The embodiment is different from the second embodiment in which the anti-squart control is performed by using the engine rotation acceleration (or its change amount).
In order to prevent erroneous operation at engine startup, anti-squat control is prohibited until the following damping force switching permission conditions are both satisfied.

Engine speed Ne ≧ k _NE (eg, k
_NE = 500 rpm) After the above conditions are met, the vehicle body speed is the vehicle body speed V _{BF for the} first time.
When ≧ k _VB (for example, k _VB = 10 km / h).

The configuration of this embodiment is similar to that of the second embodiment. The processing contents of the ECU 1 in this embodiment will be described based on the flowchart of FIG. 18 focusing on the difference from the second embodiment.

In step 322, the vehicle speed V _BF is calculated from the wheel speed sensor (similar to the first embodiment) signal in the same manner as in the first embodiment. In step 324, it is judged whether or not both of the above-mentioned damping force switching permission conditions are satisfied, and when not satisfied, the damping force is not switched and this routine is ended, while in step 324, both damping force switching permission conditions are satisfied. When it is determined that the condition is satisfied, the routine proceeds to step 330, where a damping force switching command signal is output based on the engine rotation acceleration (or its change amount).

When it is determined in step 324 that the damping force switching permission condition is not satisfied, a standard is provided by providing a means for 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, and as a result, the damping force may not be switched.

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

Engine speed ≧ k _NE (eg 500r
pm) continues for a predetermined time (for example, 3 seconds). Next, an eighth embodiment will be described. The eighth embodiment is characterized in that, unlike the third embodiment, the anti-squat 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, and the configuration is the third embodiment. Similar to the example.

Next, the difference from the third embodiment will be mainly described with reference to the flowchart shown in FIG. Step 46
At 0, the vehicle body speed V _BF is calculated in the same manner as in the first embodiment.
In step 470, it is determined whether or not both the damping force switching permission conditions are satisfied, and if not, step 54
It goes to 0 and the damping force remains soft and is not switched. On the other hand, when both the damping force switching permission conditions are satisfied in step 470, the process proceeds to step 510, and the damping force is switched according to the change amount ΔdNe of the engine rotation acceleration and the change amount ΔG _BF of the vehicle body acceleration as in the third embodiment. Performs anti-squat control.

Further, when the damping force switching permission condition is not satisfied in step 470, the damping force may be controlled at least in accordance with the change ΔG _BF of the vehicle body acceleration by performing a process of proceeding to step 530. According to this control method, the vehicle squat state immediately after the engine is started can be detected only by the ΔG _BF without using the engine rotational acceleration, and the damping force control can be performed. Can be suppressed.

Incidentally, instead of the switching permission condition,
The conditions may be used as described above. Next, a ninth embodiment will be described.

In the ninth embodiment, the engine rotation acceleration Δd.
Instead of Ne, the variation Δθ of the throttle opening θ is combined with the variation ΔG _{BF of the} vehicle body acceleration to perform squat control.

Therefore, in this embodiment, the throttle sensor is provided. FIG. 20 shows the processing contents of the ECU 1 in this embodiment. Hereinafter, steps having the same processing contents as those in the third embodiment are designated by the same step numbers, and the description thereof will be omitted.

In steps 422 and 424, the throttle opening θ and the change Δθ in the throttle opening per unit time are calculated from the throttle sensor signal. Hereinafter, the change amount Δθ of the throttle opening and the change amount ΔG of the vehicle body acceleration
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 _BF is executed. In step 500A, steps 520 and 550 of the third embodiment are steps 525 and 525, respectively.
Replaced by 555 and otherwise the same, so step 5
Only 25 and 555 will be described.

At step 525, it is determined whether or not the change amount Δθ switching reference value k _{SHS of the} throttle opening is equal to or more than the reference value k _SHS . 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 .

As a result, the amount of change in the throttle opening Δθ
Thus, the damping force switching control can be performed before the vehicle attitude change, and further, the control can be ended at the timing when the vehicle attitude change is suppressed by the change amount ΔG _BF of the vehicle body acceleration.

It should be noted that the switching of the damping force is not limited to two steps, but may be switched in multiple steps or continuously. Next, a tenth embodiment will be described.

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

FIG. 21 shows the processing contents of the ECU 1 in this embodiment. Hereinafter, the difference from the second (or first) embodiment will be mainly described, and the same processing contents will be denoted by the same step numbers and description thereof will be omitted.

In step 100, the left and right wheel speeds Vl, V
r is calculated, and the wheel speeds Vl and V are calculated in step 105.
A low-pass filter process (cut-off frequency f _c = 3 _HZ ) is applied to the average value of r to obtain a vehicle body speed V _BF .

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

As described above, in the present embodiment, in the medium and high speed regions, the squart control is terminated and the damping force level is returned to a predetermined level even during the squat control, so unnecessary squat control in the medium and high speed regions is performed. Can be prohibited and the ride quality can be improved.

The following conditions may be added as the control end condition. The state where the engine rotation acceleration is less than a predetermined value (for example, 2400 rpm / s) is a predetermined time (for example, 0.6
sec) continued.

Further, although the present embodiment is intended for a shock absorber in which the damping force is simply set in two steps, soft and hard, the present invention is not limited to this, and, for example, the normal auto mode can be set according to the driver's preference. Or, in the shock absorber that has two kinds of modes that can select the sport auto mode, when the normal auto mode is selected, it is set to hard during the squat control, and soft when not in the squat control, while the sport auto mode is set to When it is selected, sports running may be enjoyed as hard during squat control and medium soft when not under control.

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

Therefore, in this embodiment, a throttle opening switch for detecting whether or not the throttle is opened,
A stop switch is provided to detect whether or not the brake petal is stepped on.

The control in this embodiment will be described below with reference to FIG.
This will be explained using a row chart. First, step 111
Wheel speed V at 0_WProcess to import. That
Then, in step 1120, the above step 1110 is executed.
Wheel speed V _WEstimated vehicle speed V from_BCalculate
Put out. As a concrete calculation method,
Estimate maximum speed Vehicle speed V_BAnd Also, consider turning
Estimate the average of the left and right wheel speeds_BGood as
Yes. Furthermore, this estimated vehicle speed V_BBased on the front-back direction
Acceleration dV_BTo calculate.

[0111] At step 1130, a band-pass filter 1～2H _Z is the resonance frequency of the sprung (B. P.
F) Processing is applied to the wheel speed V _W taken in step 1110, and the filtered speed signal is amplified to calculate the sprung mass vibration estimation signal V _US . The calculated sprung mass vibration estimation signal V _US is as shown in FIG. In step 1140, the wheel acceleration dV _w is calculated by obtaining the time change rate of the wheel speed V _W acquired in step 1110. 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 performing full-wave rectification on the filtered wheel acceleration dV _a signal, the filtered wheel acceleration velocity absolute value dV _b
Is calculated, and a predetermined time constant (for example, about 0.5 sec) is added to the filtered wheel acceleration absolute value dV _b.
Then, the road surface state signal dV _sp is calculated by smoothing the above-mentioned filtered wheel acceleration absolute value dV _b by the above filter processing. The filtered wheel acceleration absolute value dV _b is shown in FIG.
(D), the road surface state signal dV _SP is as shown in FIG. 23 (e).

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

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

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 level for 1SC, 1SD is calculated. 25, 26
As is apparent from, 1DC, 1DB, 1SC, 1SD is made to change according to the estimated vehicle speed V _B.

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

In step 1210, step 1190 is executed.
And the determination basic levels 1DC, 1DB, 1SC, 1SD and the correction coefficients KDC, KDB, calculated in step 1200.
The threshold values L9 to L12 are corrected by the following equation from KSC and KSD.

[0117]

[Equation 10] L9 = 1DB × KDB

[0118]

[Equation 11] L10 = 1DC × KDC

[0119]

[Equation 12] L11 = 1SD × KSD

[0120]

[Equation 13] L12 = 1SC × KSC At step 1220, the dive of the vehicle is judged from the posture change states of the vehicle by comparing the on / off of the stop switch signal STP and the longitudinal acceleration dV _B with the threshold value. To do. The step 1220 will be described in detail. As shown in FIG. 29, the stop lamp switch determination STP is performed.
Is off, or when the longitudinal acceleration dV _B > threshold value L9, it is determined that the load has not moved to the front of the vehicle, and the posture change determination level Y = G. When the stop switch signal STP is on and the threshold value L10 ≦ forward / backward acceleration dV _B ≦ threshold value L9, it is determined that the load is slightly moving to the front of the vehicle due to slow braking. , Posture change determination level Y = H. When the stop switch signal STP is on and the longitudinal acceleration dV _B <threshold value L10, it is determined that the load is moving considerably 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 is judged.
Constant THR on / off and longitudinal acceleration dV_BThreshold
Compared with the value,
Judge both squats. Step 1230 in detail
To explain, as shown in FIG. 30, throttle opening determination
When THR is off or longitudinal acceleration dV _B
<When the threshold value is L11, the load moves to the rear of the vehicle.
When it is determined that the change has not been made, the posture change determination level Y = G.
The throttle opening determination THR is on and the threshold
Value L11 ≤ longitudinal acceleration dV_B≤ threshold L12
In the meantime, 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 Y = H. slot
The throttle opening determination THR is on and the longitudinal acceleration is
dV_B> When the threshold value is L12, sudden acceleration accelerates the vehicle rear part.
It is judged that the load is moving considerably, and
The constant level Y = I.

When the posture change state of the vehicle is determined in the above steps 1220 and 1230, step 124
Go to 0. In Step 1240, Step 1230,
The attitude change determination levels Y in 1240 are compared with each other, and the one having the highest level is set as the maximum value Y ′ of the attitude change determination level. However, the magnitude of the level is G <H <I
Has become. For example, the posture change determination level Y = G in step 1220, the posture change determination level Y = I in step 1230, 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 optimum 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. The map shown in FIG. 31 will be described. When the posture of the vehicle changes on a good road or a normal road, the damping force is set to hard, but when the posture changes on a bad road, the damping force is set. To medium. As a result, it is possible to prevent the posture from changing and maintain an optimal vehicle posture while reducing the ruggedness due to the unevenness of the road surface. For example, in step 1240, the maximum value Y ′ = I of the posture change determination level, 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 one example, and in addition to the above maps, maps having various characteristics can be adopted.

As described above, in the eleventh embodiment,
Road surface condition signal dV according to the bottom information _SPTo correction coefficient KD
C, KDB, KSC, KSD are calculated, and these correction factors KDC,
Correct the threshold values L9 to L12 using KDB, KSC, KSD
is doing. The correction factors KDC, KDB, KSC, KSD are
State signal dV_SPIs larger, the larger the
When driving on a rough road, the threshold values L9 to L12 are
It is corrected to be larger.

Therefore, even when the attitude of the vehicle changes, the signal indicating the attitude of the vehicle does not easily exceed the threshold value while the vehicle is traveling on a rough road, and the damping force is hard to set hard. It is possible to maintain the optimum vehicle posture while reducing the ruggedness due to the unevenness of the road surface.

Further, in the present embodiment, the threshold value to be judged is corrected by the road surface condition signal. On the contrary, a signal for detecting the dive or squat condition of the vehicle (for example, longitudinal acceleration d
V _B and its change amount, engine rotational acceleration dNe, and its change amount, throttle opening θ, and its change amount Δθ) are set so that the signal strength becomes smaller as the road surface state signal becomes larger (bad road). Perform modifications such as correction,
You may raise the same effect.

Next, the twelfth embodiment will be described. In the fourth embodiment, the anti-dive control is performed in which the damping force is increased (hard) whenever the level of the stop switch signal STP changes, but in the present embodiment, the above control is performed only in the high vehicle speed range and the low vehicle speed. In the area, the dive state of the vehicle is detected based on the change ΔG _BF of the vehicle body acceleration, and the stop switch signal STP is increased by increasing the damping force (hard) only when it is determined from the magnitude that it is necessary.
The feature is that it eliminates unnecessary increase of the damping force by changing the level of, and improves the riding comfort on a rough road surface during braking.

The fourth embodiment (FIG. 12) will be described below with reference to FIG.
The explanation will focus on the differences with. Step 600 of FIG.
In step 630, the same as steps 600 to 630 in FIG.
And the above ΔG_BFAnd the acquisition of the STP signal
Performed in step 640 and determined in step 600
From the average value of the left and right wheel speeds, the vehicle speed V _BFCalculate
It This STP signal level change and ΔG_BFDecay based on
Step A corresponding to force switching determination I (hereinafter, control I)
700 and damping force switching judgment II (hereinafter control II)
Step A800 and damping force switching (Step A
910, A920) is executed.

In step A710, it is determined whether or not the control I is being executed. If it is determined that the control I is not in progress, the process proceeds to step A720, and it is determined whether the control I condition shown below is satisfied.

Control I condition: The vehicle speed is 60 km / h or more when STP is changed from OFF to ON. When it is determined that the control I condition is satisfied, step A9
Proceed to step 20 and switch the damping force to hard.

In step A720, the control I
If it is determined that the condition is not satisfied, the process proceeds to step A810, and it is determined whether or not the control II is being performed. When it is determined that the control II is not in progress, the process proceeds to step 820, and it is determined whether the following control II conditions are 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 control II condition is satisfied, step A
920 or step A910, the command value signal for making the damping force hard or soft is output, and this routine is ended.

In step A710, the control I
If it is determined to be 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, 0.5S) 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 remains hard. On the other hand, 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 control II is in progress, the process proceeds to step A830, and it is determined whether or not the following control II termination condition is satisfied. Control II termination condition: | ΔG _BF | <predetermined value (for example, 0.
The state of 02G / 32ms) continues for a predetermined time (for example, for 1s).

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

Next, a thirteenth embodiment will be described. In the first to twelfth embodiments, the dive and squat generated by the driver's intended action (pressing the brake or stepping on the throttle) is controlled. It controls the dive and squat caused by the external disturbance. That is, the present embodiment is characterized in that when the vehicle is subjected to disturbance, the apparent air resistance increases and the vehicle body 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 hard set by comparing the change ΔG _BF of the vehicle body acceleration with a reference value. In addition, since the dive and squat generated at this time are usually smaller than the dive and squat generated when the brake accelerator is activated, if the shock absorber can set the damping force in multiple stages, the soft The return may be performed in the same manner as in the first embodiment.

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

Further, since the noise component is large in the raw vehicle body acceleration calculated as the differential value of the vehicle body speed V _BF (change amount within the predetermined time), the frequency component necessary for estimating the behavior in the front-rear direction of the vehicle is calculated. A vehicle body acceleration G _BF is calculated by subjecting a raw vehicle body acceleration to a low-pass filter having a predetermined cut-off frequency (for example, 3H _Z ) for extraction, and the vehicle body acceleration is further changed within a predetermined time period from this G _BF. The change amount ΔG _{BF of} acceleration may be calculated.

Further, in the above embodiment, a large number of reference values may be set to finely switch the damping force. As a result, the switching shock is alleviated 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 apparatus of the first aspect, the change amount of the vehicle body acceleration is calculated by using the signal from the wheel speed sensor, and the change of the vehicle body acceleration is performed. Since the damping force of the shock absorber is adjusted based on the minute, it is possible to calculate the amount of change in vehicle body acceleration without using an acceleration sensor, and it is possible to suppress attitude changes such as nose dive and squat with good responsiveness. There is an effect.

Further, according to the damping force variable shock absorber control device of the second aspect, since the damping force of the shock absorber is adjusted based on the change amount of the rotational acceleration of the engine, responsiveness of the nose dive, squat, etc. can be improved. This has the effect of suppressing posture changes.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a control procedure of the first embodiment.

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

FIG. 4 is a waveform diagram illustrating 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 showing a configuration of a second embodiment.

FIG. 7 is a flowchart showing the control procedure of the second embodiment.

FIG. 8 is a waveform diagram illustrating the operation of the third embodiment of the present invention.

FIG. 9 is a flowchart showing the control procedure of the third embodiment.

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

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

FIG. 12 is a flowchart showing the control procedure of the fourth embodiment.

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

FIG. 14 is a flowchart showing a control procedure of the fifth embodiment.

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

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

FIG. 17 is a flowchart showing the control procedure of the sixth embodiment.

FIG. 18 is a flowchart showing the control procedure of the seventh embodiment.

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

FIG. 20 is a flowchart showing the control procedure of the ninth embodiment.

FIG. 21 is a flowchart showing the control procedure of the tenth embodiment.

FIG. 22 is a flowchart showing the control procedure of the eleventh embodiment.

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

FIG. 24 is a characteristic diagram showing 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
Indicates the relationship between DC and lDB

FIG. 26 is a map showing the relationship between the estimated vehicle speed V _B and the squat determination reference levels 1SC and 1SD.

FIG. 27 is a road surface state signal dV _SP and a dive determination correction coefficient K.
It is a map showing the relationship between DC and KDB.

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

FIG. 29 is a characteristic diagram showing the relationship between the stop switch signal STP, the longitudinal acceleration dV _B, and the posture change determination level Y.

FIG. 30 is a characteristic diagram showing the relationship among the throttle opening determination THR, the longitudinal acceleration dV _B, and the posture change determination 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 the control procedure of the twelfth embodiment.

[Explanation of symbols]

 1 electronic control device 2 vehicle speed sensor 3 engine speed sensor 4 input buffer 5 input buffer 6 shock absorber 10 drive circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Takemoto, 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihon Denso Co., Ltd. (72) Inventor, Mikio Tanabe, 1-1, Showa-cho, Kariya city, Aichi prefecture Within the corporation

Claims (2)

[Claims] 1. A wheel speed sensor for detecting a wheel speed, and a removing means for removing a frequency component included in a wheel speed signal detected by the wheel speed sensor, which is equal to or higher than a resonance frequency of a vehicle body. A vehicle body acceleration calculating means for calculating a vehicle body acceleration based on a predetermined arithmetic expression from a wheel speed signal from which a frequency component above the resonance frequency of the vehicle body is removed, and a change amount calculation for calculating a change amount of the vehicle body acceleration from the vehicle body acceleration. Means, a control means for outputting a control signal so as to adjust the damping force of the shock absorber based on the amount of change in the wheel acceleration, and the damping force of the shock absorber is adjusted according to the control signal from the control means. A damping force variable shock absorber control device, comprising: 2. An engine rotation speed detecting means for detecting an engine rotation speed, an engine rotation acceleration calculating means for calculating an engine rotation acceleration from the engine rotation speed, and a change amount of the engine rotation acceleration from the engine rotation acceleration. Change amount calculating means, control means for outputting a control signal so as to adjust the damping force of the shock absorber based on the change amount of the engine rotation acceleration, and the shock absorber according to the control signal from the control means. A damping force variable shock absorber control device comprising: an adjusting unit that adjusts the damping force of the shock absorber.