JPH11268512A - Attenuation coefficient controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a maneuverability in a vehicle transient turn by making different shock-absorber attenuation coefficients of inner and outer wheels turning so as to reduce the vehicle height. SOLUTION: A transient turning state of a vehicle is detected (S40), a turning direction thereof is detected (S70), a stroke speed of each wheel is computed (S60, 80, and 90), and a roll increasing process of the vehicle body is detected (S100, 140). Each shock-absorber attenuation coefficient Cj is computed (S110, 150) so that the turning inner shock-absorber attenuation coefficient is higher than that of the turning outer shock absorber when the roll of the vehicle body is increasing, while each shock-absorber attenuation coefficient Cj is computed (S120, 160) so that the turning outer shock-absorber attenuation coefficient is higher than that of the turning inner shock absorber when the roll of the vehicle body is decreasing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping coefficient control device for a vehicle such as an automobile, and more particularly to a damping coefficient control device improved so as to improve the dynamic performance of the vehicle during a transient turn.

[0002]

2. Description of the Related Art As one of damping coefficient control devices for vehicles such as automobiles provided with a damping coefficient variable shock absorber corresponding to each wheel, for example, as described in Japanese Patent Application Laid-Open No. 7-122518, Conventionally, a damping coefficient control device that controls a damping coefficient of a shock absorber so that the sprung does not fluctuate up and down based on a relative displacement between a sprung (body) and an unsprung (wheel) when the driver returns the steering wheel. Are known.

[0003]

Generally, in a vehicle such as an automobile, it is preferable that the center of gravity of the vehicle is low in order to improve the kinetic performance when the vehicle turns. However, in the conventional damping coefficient control device as described above, the damping coefficient of the shock absorber is controlled so that the sprung does not fluctuate up and down at the time of return steering. Yes, but it cannot improve the kinetic performance of the vehicle when turning.

The present invention provides a conventional damping coefficient control apparatus for controlling a damping coefficient of a shock absorber so that the sprung does not fluctuate up and down based on the relative displacement between the sprung and the unsprung during the return steering. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and a main problem of the present invention is to provide a difference in a damping coefficient between shock absorbers of inner and outer turning wheels during a transient turn to reduce the vehicle height, thereby making the vehicle move during a transient turn. It is to improve performance.

[0005]

According to the present invention, a main object of the present invention is to provide a damping coefficient control system for a vehicle provided with a shock absorber having a variable damping coefficient corresponding to each wheel. A means for detecting turning information of the vehicle, a means for determining a change in the roll amount of the vehicle, and a damping coefficient of the shock absorber on the inside of the turn in the process of increasing the roll amount. Means for controlling the damping coefficient relatively higher than the coefficient.

Generally, when a vehicle such as an automobile turns, a roll moment acts outward on the vehicle body due to the centrifugal force acting outward on the vehicle body acting on the vehicle body. , And the damping force of the left and right shock absorbers, and the vehicle body is rolled outward in the turning direction to a position where the roll moment balances the spring force and the damping force.

According to the first aspect of the invention, in the process of increasing the roll amount of the vehicle body, the damping coefficient of the shock absorber inside the turning is controlled to be relatively higher than the damping coefficient of the shock absorber outside the turning. As a result, the damping force of the inner shock absorber acting downward is controlled relatively higher than the damping force of the outer shock absorber acting upward, so that the downward force acting on the vehicle body as a whole increases. The vehicle height is reduced.

According to the present invention, in order to effectively attain the above-mentioned main object, the damping coefficient of the left and right front wheel shock absorbers and the damping of the right and left rear wheel shock absorbers are provided. The coefficients are configured to be controlled independently of each other (the configuration of claim 2).

According to the second aspect of the present invention, the damping coefficients of the left and right front wheel shock absorbers and the right and left rear wheel shock absorbers are controlled independently of each other. Since the damping force of the shock absorbers of the left and right rear wheels is controlled independently of each other, the downward force acting on the vehicle body on the front wheel side and the rear wheel side is controlled independently of each other as a whole, thereby the front wheel It is possible to control the posture of the vehicle body in the front-rear direction by giving a difference in the reduction amount of the vehicle height on the side and the rear wheel side.

[0010]

As shown in FIG. 3, in a two-wheel model of an actual vehicle, a vehicle body 110 is supported by left and right wheels 112L and 112R, and a suspension is provided between the vehicle body 110 and the wheels 112L and 112R. Springs 114L and 114R and shock absorber 11
6L and 116R are shown as being disposed.

In the actual vehicle model shown in FIG. 3, for example, when the vehicle turns left and an inertial force acts on the body 110 to the right, a roll moment Mroll acts outward on the body. Then, the roll moment becomes the left and right suspension springs 114L and 11L.
4R, and the damping forces Fal and Far of the left and right shock absorbers 116L and 116R are carried by the spring forces Fsl and Fsr. In the process of increasing the roll amount of the vehicle body, the moment in the roll restraining direction and the roll moment Mroll due to these forces. The vehicle body 110 rolls outward until the vehicle turns 110.

In this case, the suspension spring 114
L spring force Fsl increase and suspension spring 1
The amount of reduction of the spring force Fsr of 14R is substantially equal to each other,
Also, in a conventional vehicle, the damping coefficients of the left and right shock absorbers during turning are controlled to be equal to each other,
The damping forces Fal and Far of the left and right shock absorbers are also substantially equal to each other, so that the height of the center of gravity 118 of the vehicle does not substantially change.

On the other hand, as shown in FIG. 4, only suspension springs 114L and 114R are provided between the vehicle body 110 and the left and right wheels 112L and 112R, and are disposed inside the vehicle with respect to turning. Considering a virtual model in which one shock absorber 122 that generates a vertical damping force between a virtual wheel 120 and one shock absorber 124 that suppresses roll displacement of a vehicle body is considered, a roll moment Mroll is carried by the damping force Fas of the shock absorber 122 and the spring forces Fsl and Fsr of the left and right springs 114L and 114R, and the increase in the vehicle height on the turning inner wheel side is reduced as compared with the conventional case. , The height of the center of gravity 118 decreases.

Therefore, if the control of the virtual model as shown in FIG. 4 can be achieved in the two-wheel model of the actual vehicle shown in FIG. 3, the height of the center of gravity 118 of the vehicle in the process of increasing the roll amount of the vehicle. Therefore, the kinetic performance of the vehicle at the beginning of turning can be improved.

As shown in FIG. 4, the spring constant of the left and right suspension springs 114L and 114R is K, the damping coefficient of the shock absorber on the turning outer wheel is Cout, the stroke of the turning outer wheel is Xout, and the turning inner wheel is Xout. The damping force of the shock absorber 114L on the
, The stroke of the turning inner wheel is Xin, the tread of the vehicle is W, the center of gravity 118 of the vehicle and the shock absorber 1
22 as L, and the shock absorber 122
, And 124 are Cg and C, respectively.

Assuming that the mass of the vehicle body 10 is M, the vertical acceleration and the roll angular velocity of the vehicle body are Xbdd and θdd, respectively, and the stroke speeds of the turning outer wheel and the turning inner wheel are Xout and Xind, respectively, the virtual model shown in FIG. Equations 1 and 2 below are respectively established from the balance of the vertical force and the balance of the force around the center of gravity 118 in the above.

(Equation 1)

Assuming that Cn = WC / 2 as a parameter for attenuating the roll motion of the vehicle body, the above equation 2 becomes the following equation 3
It is represented as

(Equation 2)

The following equations 4 and 5 are established from the balance of the vertical force and the balance of the force around the center of gravity 118 in the actual two-wheeled vehicle model shown in FIG.

(Equation 3)

From the above equations 1 and 4, the following equation 6 is established.

(Equation 4)

If Cm = Cn / L, the following equation 7 is established from the above equations 3 and 5.

(Equation 5)

When the vertical force generated by the shock absorber 122 in the virtual model shown in FIG. 4 is represented by T according to the following equation 8, the following equations 9 to 11 are established from the above equations 6 to 8. I do.

[0022]

(Equation 6)

(Equation 7)

From Equations 9 and 11, the damping coefficient Cin of the shock absorber for the turning inner wheel can be obtained as follows.

(Equation 8)

The damping coefficient Cout of the shock absorber of the turning outer wheel can be obtained as follows by substituting the equation 12 into the equation 9.

(Equation 9)

Further, by rearranging the above equations (12) and (13), the damping coefficient Cin of the shock absorber of the turning inner wheel and the turning outer wheel is obtained.
And Cout are represented by the following equations 14 and 15, respectively.

(Equation 10)

The damping forces generated by the shock absorbers on the turning inner wheel side and the turning outer wheel side are given by the following equations, respectively.
6 and Equation 17.

[Equation 11]

Based on the same concept, in the process of decreasing the roll amount of the vehicle body, the turning inner wheel side and the turning outer wheel side are based on a virtual model in which virtual shock absorbers 122 and 124 are disposed outside the turning of the vehicle. The damping coefficients Cin and Cout of the shock absorber of
And the control as in Equation 19, the center of gravity 11 of the vehicle is obtained.
8, the height of the vehicle at the end of turning can be improved.

(Equation 12)

Therefore, according to one preferred aspect of the present invention, in the configuration of the first aspect, the damping coefficient Cin of the shock absorber on the inside of the turn and the shock absorber on the outside of the turn in the process of increasing the roll amount of the vehicle body. Damping coefficient C
out is configured to be calculated according to the above equations 14 and 15, respectively (preferred mode 1).

According to another preferred embodiment of the present invention, in the configuration of the first aspect, in the process of decreasing the roll amount of the vehicle body, the damping coefficient of the shock absorber on the outer side of the turn is smaller than the shock absorber on the inner side of the turn. It is configured to be controlled to be higher than the damping coefficient of the absorber (preferred mode 2).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 2, the damping coefficient Cin of the shock absorber inside the turn and the damping coefficient Cin outside the turn are included in the process of decreasing the roll amount of the vehicle body. The damping coefficient Cout of the shock absorber is configured to be calculated according to Equations 18 and 19 above (preferred embodiment 3).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 1, L, W, T, Cg, and C for the front wheel and the rear wheel are respectively represented by Lf, Lr, Wf, and Lf. Wr, Tf and Tr, Cgf and Cgr, Cf
, And Cr, the stroke speeds of the turning inner front wheel and the turning outer front wheel are denoted by Xfind and Xfoutd, respectively, and the stroke speeds of the turning inner rear wheel and the turning outer rear wheel are denoted by X, respectively.
rind and Xroutd, and Tf and Tr are values represented by the following formulas 20 and 21, respectively. In the process of increasing the roll amount of the vehicle, the damping coefficient Cfin of the shock absorber of the front inside wheel and the shock of the front outside wheel are increased. The damping coefficient Cfout of the absorber is calculated according to the following formulas 22 and 23, respectively. The damping coefficient Crin of the shock absorber for the turning inner rear wheel and the damping coefficient Crout of the shock absorber for the turning outer rear wheel are respectively expressed by the following formulas 24 and 25. (Preferred mode 4).

[0032]

(Equation 13)

[Equation 14]

Similarly, according to another preferred embodiment of the present invention, in the configuration of the above-mentioned preferred embodiment 3, the damping coefficient Cfin of the shock absorber of the front inner wheel and the turning in the process of decreasing the roll amount of the vehicle body. The damping coefficient Cfout of the outer front wheel shock absorber is calculated according to the following equations 26 and 27, and the damping coefficient Crin of the turning inner rear wheel shock absorber and the damping coefficient Crout of the turning outer rear wheel are respectively expressed by the following equations. 28 and Equation 29 (preferred mode 5).

[0034]

(Equation 15)

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing one preferred embodiment of the damping coefficient control device according to the present invention.

In FIG. 1, 10FL and 10FR indicate left and right front wheels of the vehicle 12, respectively, and 10RL and 10RR indicate left and right rear wheels, respectively. The left and right front wheels 10FL and 10FR, which are steered wheels, are steered via tie rods 18L and 18R by a rack and pinion type power steering device 16 driven in response to turning of the steering wheel 14 by the driver.

A variable damping coefficient type shock absorber 22FL is provided between each of the wheels 10FL to 10RR and the vehicle body 20.
.About.22RR, and the damping coefficient Ci (i = fl, fr, rl, rr) of each shock absorber is controlled by the electric control device 24 when the vehicle turns, as described later.

The electric control device 24 has a vehicle height sensor 26F.
Signals indicating the strokes Xi (i = fl, fr, rl, rr) of the wheels 10FL to 10RR are input from L, 26FR, 26RL, 26RR and a signal indicating the lateral acceleration Gy from the lateral acceleration sensor 28.

Although not shown in detail in the figure, the electric control device 24 has, for example, a CPU, a ROM, a RAM, and an input / output port device, which are generally connected to each other by a bidirectional common bus. Microcomputer with a typical configuration. The vehicle height sensors 26FL to 26RR detect the stroke of the wheel with the bounding direction of the wheel being positive, and the lateral acceleration sensor 28 detects the lateral acceleration with the positive left turning direction of the vehicle.

The electric control unit 24 determines whether or not the vehicle is in a transient turning state based on the lateral acceleration Gy according to a flowchart shown in FIG. 2 as will be described later. The damping coefficient Ci of the shock absorber is controlled to a predetermined hard damping coefficient Ch, and even if the vehicle is in a transient turning state, the damping of the shock absorber inside the turning is increased in the process of increasing the roll amount of the vehicle body. Control the coefficient so that it becomes higher than the outside damping coefficient.On the contrary, in the process of decreasing the roll amount of the vehicle body, make each shock so that the damping coefficient of the shock absorber outside the turning becomes higher than the damping coefficient inside the turning. The damping coefficient of the absorber is controlled, thereby lowering the vehicle height during a transient turn and lowering the center of gravity of the vehicle body.

Next, the control of the attenuation coefficient in the illustrated embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch (not shown) and is repeatedly executed at predetermined time intervals.

First, in step 10, a signal indicating the stroke Xi of each wheel and a signal indicating the lateral acceleration Gy of the vehicle body are read, and in step 20, the absolute value of the lateral acceleration Gy is controlled. Reference value Gyo as value
(Positive constant) is determined, that is, it is determined whether the control of the damping coefficient of the shock absorber at the time of turning of the wheel is required. When the determination is negative, the process proceeds to step 30.

In step 30, the damping coefficient of the shock absorber for each wheel is set in accordance with a normal control routine when the vehicle is not turning, and thereafter in step 18
Go to 0. The control of the damping coefficient in this case may be performed in any manner known in the art.

In step 40, the time differential value ΔGy of the lateral acceleration Gy is calculated, and the time differential value ΔGy is calculated.
Is determined whether or not the absolute value of the vehicle exceeds the reference value ΔGyo (positive constant), that is, whether or not the vehicle is in a transient turning state.
When the determination is negative, the damping coefficient Ci of the shock absorber of each wheel is set to the preset hard damping coefficient Ch in step 50, and then the routine proceeds to step 180.

In step 60, the time differential value (stroke speed) Xid (i = fl,
fr, rl, rr) are calculated, and in a step 70, it is determined whether or not the lateral acceleration Gy is positive, that is, whether or not the vehicle is turning left, and an affirmative determination is made. If so, the process proceeds to step 80, and if a negative determination is made, the process proceeds to step 90.

In step 80, the stroke speed Xfind of the inside front wheel is set to the stroke speed Xfld of the front left wheel, the stroke speed Xfoutd of the front outside wheel is set to the stroke speed Xfrd of the right front wheel, The stroke speed Xrind is the stroke speed Xrl of the left rear wheel
d and the stroke speed Xroutd
Is set to the stroke speed Xrrd of the right rear wheel.

Similarly, in step 90, the stroke speed Xfind of the turning inner front wheel becomes equal to the stroke speed X of the right front wheel.
frd and the stroke speed Xfout of the front outside wheel
d is set to the stroke speed Xfld of the left front wheel, the stroke speed Xrind of the turning inside rear wheel is set to the stroke speed Xrrd of the right rear wheel, and the stroke speed X of the turning outside rear wheel is set.
routd is set to the left rear wheel stroke speed Xrld.

In step 100, signGy is used as the sign of the lateral acceleration Gy, and the time differential values ΔGy and si of the lateral acceleration are used.
It is determined whether or not the product with gnGy is positive, that is, whether or not the magnitude of the lateral acceleration due to the turning of the vehicle is in the process of increasing and the roll amount of the vehicle body is increasing. If an affirmative determination is made, in step 110, the damping coefficients Cj (j = fin, fout, j) of the shock absorbers of the turning inside front wheel, turning outside front wheel, turning inside rear wheel, and turning outside rear wheel are determined.
(rin, rout) are calculated in accordance with the equations 22 to 25, and when a negative determination is made, the damping coefficient Cj of each shock absorber is calculated in step 120 in accordance with the equations 26 to 29.

In step 130, the damping coefficient Cfl of the left front wheel shock absorber is set to the damping coefficient Cfin of the turning front inner wheel, and the damping coefficient Cfr of the right front wheel shock absorber is set to the damping coefficient Cfout of the turning outer front wheel. The damping coefficient Crl of the left rear wheel shock absorber is set to the damping coefficient Crin of the turning inner rear wheel, and the damping coefficient Crr of the right rear wheel shock absorber is set to the damping coefficient Crout of the turning outer rear wheel.
Is set to

Similarly, in step 140, it is determined whether or not the product of the time differential value ΔGy of the lateral acceleration and sign Gy is positive.
At 50, the damping coefficient Cj of the shock absorber of the inside turning front wheel, the outside turning front wheel, the inside turning rear wheel, and the outside turning rear wheel is shown.
Are calculated in accordance with the above equations 22 to 25, and when a negative determination is made, in step 160, the damping coefficient Cj of each shock absorber is calculated in accordance with the above equations 26 to 29.

At step 170, the damping coefficient Cfl of the left front wheel shock absorber is set to the damping coefficient Cfout of the turning front outside wheel, and the damping coefficient Cfr of the right front wheel shock absorber is set to the damping coefficient Cfin of the turning inside front wheel. ,
The damping coefficient Crl of the left rear wheel shock absorber is set to the damping coefficient Crout of the turning outer rear wheel, and the damping coefficient Crr of the right rear wheel shock absorber is set to the damping coefficient Cri of the turning inner rear wheel.
Set to n.

In step 180, the damping coefficient of each shock absorber is determined in step 30, 50, 130 or 1
Is controlled so as to be the set attenuation coefficient at 70,
Thereafter, the process returns to step 10.

Thus, according to the illustrated embodiment, it is determined in step 20 whether or not it is necessary to control the damping coefficient of the shock absorber during turning of the wheels. It is determined whether or not the vehicle is in a transitional turning state. In step 70, the turning direction of the vehicle is determined. In steps 60, 80, and 90, the stroke speed of each wheel is obtained. It is determined whether or not the roll amount of the vehicle body is in the process of increasing. When the roll amount of the vehicle body is in the process of increasing, in steps 110 and 150, the damping coefficient Cj of each shock absorber is calculated according to the equations (22) to (22). 25, when the roll amount of the vehicle body is in the process of decreasing, in steps 120 and 160, the damping coefficient Cj of each shock absorber is calculated. Is calculated according to equations 26 to 29.

Therefore, according to the illustrated embodiment, when the vehicle is in a transient turning state in which the roll amount of the vehicle body increases,
The damping coefficient of each shock absorber is controlled so that the damping coefficient of the shock absorber inside the turn is higher than the damping coefficient outside the turn. Conversely, when the vehicle is in a transient turning state in which the roll amount of the vehicle body decreases, the outside of the turn Since the damping coefficient of each shock absorber is controlled so that the damping coefficient of the shock absorber is higher than the damping coefficient inside the turn, lowering the vehicle height, lowering the center of gravity of the vehicle body, and improving the dynamic performance of the vehicle during transient turning Can be improved.

For example, as shown in FIG. 5, the driver performs steering, whereby the lateral acceleration Gy of the vehicle body gradually increases from time t1 to time t2, and from time t2 to time t2.
Assuming that the lateral acceleration Gy is kept constant up to 3 and the lateral acceleration Gy gradually decreases from the time t3 to the time t4, the time between the time t1 and the time t2 in the process of substantially increasing the vehicle body roll amount. The damping coefficient of the shock absorber inside the turning is controlled to be higher than the damping coefficient of the shock absorber outside the turning, so that in this section, the center of gravity of the vehicle body is lower than the standard height X0, and from the time t2 to the time t3 Until then, the center of gravity of the body is the standard height X
0, and from time t3 to time t4, the damping coefficient of the outside shock absorber is controlled to be higher than the damping coefficient of the inside shock absorber, thereby increasing the height of the center of gravity of the vehicle body. It is lower than the standard height X0.

According to the illustrated embodiment, the damping coefficients of the left and right front wheel shock absorbers and the left and right rear wheel shock absorbers are controlled independently of each other. Lf and Lr, W
By appropriately setting f and Wr, Cgf and Cgr, Cf and Cr, the posture of the vehicle body in the front-rear direction at the time of transient turning of the vehicle is controlled, for example, to reduce the nose dive of the vehicle body at the beginning of turning. In addition, the nose lift of the vehicle body at the end of turning can be reduced.

Further, according to the illustrated embodiment, whether the roll amount of the vehicle body is in the process of increasing or decreasing is determined on the basis of the lateral acceleration Gy of the vehicle body, so that it is detected by, for example, the vehicle height sensors 26FL to 26RR. Stroke Xi of each wheel
The actual roll amount of the vehicle body is calculated based on the actual roll amount, and the damping of each shock absorber is more responsive than when it is determined whether the vehicle body roll amount is in an increasing process or a decreasing process based on the actual roll amount. The coefficient can be controlled.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to the above embodiment, and various other embodiments are included in the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the above-described embodiment, in the process of increasing the roll amount of the vehicle body, the damping coefficient of the shock absorber on the inside of the turn is controlled to be relatively higher than the damping coefficient of the shock absorber on the outside of the turn. In the process of reducing the roll amount of the vehicle body, the damping coefficient of the shock absorber on the outer side of the turn is controlled to be higher than the damping coefficient of the shock absorber on the inner side of the turn. Since the possibility that the behavior of the vehicle becomes unstable in the initial stage) is lower than that in the process of increasing the roll amount of the vehicle body, the damping coefficient of the shock absorber on the outer side of the turn in the process of decreasing the roll amount of the vehicle body (end of turn). May be omitted from the control to make the damping coefficient higher than the damping coefficient of the shock absorber inside the turning.

More specifically, the calculation of the damping coefficient Cj in steps 120 and 160 is omitted, and instead, the damping coefficient Ci of each shock absorber is calculated, for example, in step 50.
As in the case of (1), the damping coefficient may be set to the hard damping coefficient Ch, and then the processing may be modified to proceed to step 180.

In the above-described embodiment, it is determined whether the roll amount of the vehicle body is in the process of increasing or decreasing based on the sign of the time differential value ΔGy of the lateral acceleration Gy of the vehicle body. This determination is made, for example, using Kh as a stability factor, Rg as a steering gear ratio, H as a wheelbase, and a vehicle speed V and a steering angle sensor 32 detected by a vehicle speed sensor 30 shown in FIG.
The lateral acceleration Gys of the vehicle may be estimated based on the steering angle φ detected by the following equation (30), and may be performed based on the estimated lateral acceleration. Gys = V ² φ / [(1 + Kh V ² ) Rg H] (30)

Similarly, whether the vehicle body roll amount is in the process of increasing or decreasing is determined based on the sign of the vehicle body roll rate calculated based on the stroke Xi detected by the vehicle height sensors 26FL-26RR. You may. In this case, the roll rate may be detected by a roll rate sensor not shown in FIG.

In the above-described embodiment, the stroke speed Xid of each wheel is calculated based on the detection results of the vehicle height sensors 26FL to 26RR, but the stroke speed of each wheel is provided on the vehicle body. It may be estimated by the observer based on the vertical acceleration of the vehicle body detected by a vertical acceleration sensor not shown in the figure.

Further, in the above-described embodiment, the damping coefficient Cj of each shock absorber is calculated by the equation (22) to (25) or (26).
29, the damping coefficient of the inside shock absorber is controlled to be relatively higher than the damping coefficient of the outside shock absorber in the process of increasing the roll amount of the vehicle body. In the process of decreasing the roll amount of the vehicle body, the calculation may be performed in another manner as long as the damping coefficient of the shock absorber outside the turning is controlled to be higher than the damping coefficient of the shock absorber inside the turning.

[0066]

As is apparent from the above description, according to the structure of the first aspect of the present invention, in the process of increasing the roll amount of the vehicle body, the damping coefficient of the shock absorber inside the turn is reduced by the shock outside the turn. The damping coefficient is controlled to be relatively higher than the damping coefficient of the absorber, whereby the damping force of the shock absorber on the inside that turns downward is controlled to be relatively higher than the damping force of the shock absorber on the outside that turns upward. Thus, the downward force acting on the vehicle body as a whole increases, whereby the vehicle height can be reduced and the kinetic performance during transient turning of the vehicle can be improved.

According to the first aspect of the present invention, the vehicle height during the transient turning of the vehicle can be reduced only by controlling the damping coefficient of the shock absorber without the need for a vehicle height adjusting device. The kinetic performance of the vehicle during a transient turn can be improved at a lower cost than in the case of a vehicle requiring an adjusting device.

According to the second aspect of the present invention, the damping coefficients of the left and right front wheel shock absorbers and the left and right rear wheel shock absorbers are controlled independently of each other. Since the damping forces of the shock absorbers of the left and right rear wheels are controlled independently of each other, downward forces acting on the vehicle body on the front wheel side and the rear wheel side are controlled independently of each other as a whole, thereby By providing a difference between the reduction amounts of the vehicle height on the front wheel side and the rear wheel side, the posture of the vehicle body in the front-rear direction can be controlled.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one preferred embodiment of a damping coefficient control device according to the present invention.

FIG. 2 is a flowchart illustrating a damping coefficient control routine according to the embodiment.

FIG. 3 is an explanatory diagram showing a two-wheel model of an actual vehicle.

FIG. 4 is an explanatory diagram showing a virtual model in which a virtual shock absorber is disposed inside the turning of the vehicle.

FIG. 5 is a time chart showing an example of the operation of the embodiment.

[Explanation of symbols]

 Reference Signs List 14 steering wheel 16 power steering device 20 vehicle body 24 electric control device 26FL-26RR vehicle height sensor 28 lateral acceleration sensor 110 vehicle body 112L, 112R wheels 114L, 114R suspension spring 116L, 116R shock absorber 122, 124 ... Shock absorber

Claims (2)

[Claims] 1. A vehicle damping coefficient control device provided with a shock absorber having a variable damping coefficient corresponding to each wheel, means for detecting turning information of the vehicle, means for determining a change in the roll amount of the vehicle body, Means for controlling the damping coefficient of the shock absorber inside the turn to be relatively higher than the damping coefficient of the shock absorber outside the turn in the process of increasing the roll amount of the vehicle body. . 2. The damping coefficient control device according to claim 1, wherein the damping coefficients of the left and right front wheel shock absorbers and the left and right rear wheel shock absorbers are controlled independently of each other.