JP2000025491A - Vehicle behavior control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an engine brake from disturbing the behavior of a vehicle by judging the effect given to the behavior of the vehicle by the engine brake, and controlling the engine brake based on it. SOLUTION: This vehicle behavior control device 10 considers whether an engine brake gives an effect to a vehicle behavior or not and whether inadvertent acceleration occurs on the vehicle or not and controls the engine brake on the desirable condition. When the hydraulic brake force exceeds the engine brake force, idle-up control is made. When the engine brake force exceeds the hydraulic brake force on the contrary, the engine brake is reduced. The hydraulic brake force becomes a half of the whole brake force or above, there is a time difference until the actual rise of driving force after the control, therefore a disturbance of the vehicle behavior and a sense of incompatibility given to an occupant can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a behavior control device for preventing the behavior of a vehicle from becoming unstable.

[0002]

2. Description of the Related Art A conventional vehicle behavior control device of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 9-207736. This device is used to avoid the occurrence of oversteer in the case of rear-wheel drive vehicles and understeer in the case of front-wheel drive vehicles due to the braking balance of the front and rear wheels being disrupted by the engine braking of the drive wheels. The slip ratio of the moving wheels, that is, the ratio of the difference between the vehicle speed (vehicle speed) and the wheel speed (wheel speed) to the vehicle speed is increased.

[0003] However, in such a conventional vehicle behavior control device, in order to increase the target slip ratio of the driven wheels, the driven wheels tend to reach the friction limit, and it is difficult to sufficiently control the behavior of the vehicle. There was a problem that it became impossible.

In order to solve such a problem, it is conceivable that during vehicle behavior control, idle-up control of the engine to reduce engine braking, that is, opening a throttle valve to increase the engine speed. However, if the idle-up control is performed at the same time as the behavior control of the vehicle, there is a problem that a driver or a passenger may feel uncomfortable because the feeling of deceleration due to the engine brake is reduced.

[0005]

SUMMARY OF THE INVENTION According to the present invention, by appropriately controlling engine brake reduction, it is possible to prevent the behavior of a vehicle from being disturbed by engine brake and to reduce the driver The purpose is to solve the problem that passengers feel uncomfortable.

[0006]

For this purpose, a vehicle behavior control device according to a first aspect of the present invention provides an actual yaw rate detecting means for detecting an actual yaw rate actually occurring in a vehicle. And a target yaw rate calculating means for calculating a target yaw rate to be achieved by the vehicle, wherein the operation of the engine brake is determined by a vehicle behavior control device that controls the behavior of the vehicle according to a deviation between the actual yaw rate and the target yaw rate. An engine brake operation determining means; and an influence determining means for determining an effect of the engine brake on the behavior of the vehicle. When the influence determining means determines that the behavior of the vehicle is affected by the engine brake, the engine is activated. The control is performed to reduce the brake.

According to a second aspect of the present invention, in the vehicle behavior control device, the influence judging means may include an engine braking force calculating means, a hydraulic braking force calculating means, and a comparison between the engine braking force and the hydraulic braking force. Means.

According to a third aspect of the present invention, in the vehicle behavior control device, the influence judging means compares the engine braking force with the hydraulic braking force, and when the engine braking force exceeds the hydraulic braking force, It is characterized in that it is determined that the engine brake affects the behavior of the vehicle.

[0009]

According to the present invention, the influence of the engine brake on the behavior of the vehicle is determined to control the behavior of the vehicle, and the engine braking force is reduced based on the determination. Therefore, it is possible to prevent the behavior of the vehicle from being disturbed by the engine brake, and also to avoid giving the occupant of the vehicle a sense of discomfort.

According to the second aspect of the present invention, the engine braking force and the hydraulic braking force are obtained, respectively, and the two are compared. This makes it possible to control the reduction of the engine brake at an appropriate timing.

Further, according to the third aspect of the present invention, the engine braking force and the hydraulic braking force are compared, and control for reducing the engine brake is performed based on the result. Therefore, it is possible to control the behavior of the vehicle without performing complicated control such as taking measures to prevent a sudden change in torque when performing engine control.

[0012]

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

FIG. 1 is a block diagram showing a configuration of a vehicle behavior control device according to the present invention. The vehicle behavior control controller 11 of the present device 10 includes a vehicle behavior control unit 21 and an engine brake control unit 22. Wheel speed, steering angle, and the like are determined by various sensors 23 described later.
, The signal processing operation section 21a performs the operation processing, and then the target yaw rate operation section 21b obtains the target yaw rate. Next, the target braking force is calculated by the target braking force calculation unit 21c, and finally a drive signal is sent from the drive pulse output unit 21d to the brake actuator 14 to control the brake pressure.

On the other hand, in the engine brake control unit 22, the calculation results of the signal processing calculation unit 21a and the target braking force calculation unit 21c are input to the condition determination unit 22a. / AT controller
An engine control signal is output to 12. A throttle control signal is sent from the engine / AT controller 12 to the throttle motor 13 to perform idle-up control of the engine.

FIG. 2 is a diagram showing the structure of the brake actuator 14 shown in the block diagram of FIG. In the present vehicle, a vehicle behavior control device is disposed between the brake operation unit 101 and the left and right front wheels 102L and 102R and the left and right rear wheels 103L and 103R. The brake operation unit 101 includes a brake pedal 101a and a booster 101b that amplifies a force for depressing the brake pedal 101a.
And a master cylinder (M / C) 101c that receives the amplified force to compress the brake fluid and generate a brake pressure, and a reservoir tank 101d that stores the brake fluid. Left and right front wheels 102L, 102R and left and right rear wheels 103L, 103R are wheel cylinders (W / C) 104L, 104R and 105, respectively.
L, 105R.

These wheel cylinders 104L, 104R, and 10
The hydraulic pressure of 5L, 105R is the same as that of the conventional anti-skid device, and the inlet valves 106, 107, 108,
109 and outlet valves 110, 111, 112, 113
Controlled by. At that time, the reservoir 114
And 115 are pumped into damper chambers 119 and 120 by pumps 117 and 118 driven by a motor 116, and the inlet valves 106, 107,
Returned upstream of 108 and 109.

When the wheel cylinder pressure is controlled during non-braking, the inlet valves 121 and 122, which are solenoid valves, are closed to cut between the master cylinder 101c and the wheel cylinders 104L, 104R and 105L, 105R. Certain outlet valves 123 and 124 are opened to allow pumping of brake fluid from reservoir tank 101d. Also, relief valves 125 and 126 are provided in parallel with inlet valves 121 and 122, respectively.

In the vehicle behavior controller 11, inlet valves (switching valves) 106, 107, 108, 109, 121
, 122 and outlet valves (switching valves) 110, 111
, 112, 113, 123, and 124 to control the behavior of the vehicle, and a wheel speed sensor as the various sensors 23.
Wheel speed V _wi from 128L, 128R, 129L, 129R (i = 1,
2, 3, 4), the steering angle θ from the steering angle sensor 130,
The yaw rate Y from the yaw rate sensor 131, the lateral acceleration Yg from the lateral acceleration sensor 132, the vehicle speed V from the vehicle speed sensor 133, and the master cylinder pressure PM _{/ C} from the master cylinder pressure sensor 134 are input. The controller 11 controls the yawing momentum of the vehicle by supplying an output signal obtained based on these input signals to each switching valve. In this embodiment, the lateral acceleration sensor 131 is used to detect the lateral acceleration Yg.
The lateral acceleration Yg may be obtained by calculation based on signals from one or more of the 128L, 128R, 129L, 129R, the steering angle sensor 130, the lateral acceleration sensor 132, the vehicle speed sensor 133, and the master cylinder pressure sensor 134. Note that the controller
Here, only the function of the vehicle behavior control 11 is described, but the controller 11 also has a function as a so-called ABS control device that reduces the brake fluid pressure when the wheels are locked by braking. ing.

FIG. 3 shows a peripheral configuration of the engine A / T controller and the engine driven by the throttle motor shown in the block diagram of FIG. In the figure, the displacement of the accelerator pedal 206 is detected by an accelerator opening sensor 207 and is input to the engine / AT controller 12, and the engine / AT controller 12 outputs a corresponding throttle control signal to the throttle controller 208. The throttle controller 208 sends a corresponding throttle control signal to the throttle motor 13.
, Whereby the throttle valve 204 is controlled. The opening of the throttle valve 204 is fed back to the engine / AT controller 12 by a throttle sensor 205. The vehicle behavior controller 11
If necessary, an interrupt command is output to the engine / AT controller 12 to control the throttle opening, ignition timing, fuel injection amount, and the like in accordance with a command from the vehicle behavior control controller 11 regardless of the displacement of the accelerator pedal 206. be able to.

FIG. 4 is a flowchart showing an example of a control program for vehicle behavior control executed by the controller in one embodiment of the present invention. This figure 4
The control program is executed by a non-illustrated operating system by a periodic interruption every predetermined time. Hereinafter, the processing procedure of this control program will be described.

First, at step 301, the wheel speed sensor 128
L, 128R, 129L, 129R, the steering angle sensor 130, yaw rate sensor 131, lateral acceleration sensor 132, a vehicle speed sensor 133 and the master cylinder pressure sensor 134, respectively wheel speed V _wi
(I = 1, 2, 3, 4), the steering angle θ, the yaw rate Y, the lateral acceleration Yg, the vehicle speed V, and the master cylinder pressure PM _{/ C} are read.

In the next step 302, an initial value Y ₀ ^* of the target yaw rate is calculated based on the steering angle θ and the vehicle speed V read in step 301. In the present embodiment, the calculation of the initial value of the target yaw rate includes the predetermined vehicle speeds V ₁ , V ₂ , V
₃ (V ₁ <V ₂ <V ₃ ), Y ₀ ^* = f (θ,
V) shown in FIG. 5 is used. In step 301, the controller 11 functions as a target yawing momentum calculating means.

In the next step 303, the actual slip ratio S_i
Is calculated. This actual slip ratio S_iIn the calculation of, first,
Wheel speed V of each wheel_wiTo the vehicle speed
I V _wfiIs calculated for each wheel, and conditions for braking / non-braking etc.
By each V_wfiTo choose the largest one from
Vehicle speed intermediate value V closest to vehicle speed_wfAnd calculate
V_wfVehicle speed V based on_iFind the estimated body
Speed V_iUsing the actual slip ratio S_iIs calculated by the following equation
I do.

## EQU1 ## S _i = (V _wi −V _i ) / V _i

In the next step 303, the change Jμ of the road surface friction coefficient of each wheel is obtained by the following equations.

I _i × (dω _i / dt) = T _Bi −F _w where I _i : tire inertia, dω _i / dt: tire rotation acceleration, T _Bi : brake torque, F _w : road surface transmission force.

Ω _i = V _Wi / r, where ω _i : tire rotation speed, r: tire radius

T _Bi = K ₁ × P _Bi where K ₁ : brake pressure (coefficient of proportional to brake torque, determined by friction coefficient of brake pad, piston area, etc.), P _Bi : brake pressure

[Number 5] _{F w = μW i = k i} × S i × W i However, μ: the road surface friction coefficient, W _i: wheel load, k _i: system and drive stiffness coefficient Therefore, the following equation is obtained.

K _i = (K ₁ × P _Bi −I _i × (dω _i / dt)) / (W _i × S _i ) = f (P _Bi , V _Wi , S _i , W _i )

In the above calculation, the wheel load W _i may be obtained by calculating the static load from longitudinal acceleration and lateral acceleration.
Or front wheels (rear wheels) by static front and rear weight distribution
It may be obtained a front wheel (rear wheel) average of the left and right k _i as the average.

In the present embodiment, the estimated road surface friction coefficient μ _sf of the front wheel and the estimated road surface friction coefficient μ _sr of the rear wheel are determined by averaging _ki on the left and right sides according to the following equations.

## _EQU7 ## μ _sf = (k _fl + k _fr ) / 2

Μ _sr = (k _rl + k _rr ) / 2 where k _fl = K ₁ , k _fr = k ₂ , k _rl = k ₃ , k _rr =
k is _4.

Here, in order to detect a change in the road surface friction coefficient, a ratio Jμ of the estimated road surface friction coefficient of the front and rear wheels is obtained by the following equation.

[Expression 9] Jμ = _μfs / _μrs

Thereafter, a change in the road surface friction coefficient in the front-rear direction is determined based on the Jμ. (A) If Jμ = 1, there is no change in road friction coefficient. (A) If Jμ <1, change of road friction coefficient from high μ to low μ. (C) If Jμ> 1, road friction coefficient. Is determined to change from low μ to high μ. The “change in the road surface friction coefficient from high μ to low μ” refers to a case where the rear wheel side is a high μ road and the front wheel side is a low μ road (that is, when the running path of the vehicle changes from high μ to low μ). ).

In the next step 305, the target yaw rate Y ^* , which is the target yaw momentum, is corrected using Jμ. In this step 305, the controller 11 functions as a correction unit. The correction of the target yaw rate is performed by the following equation.

[Number 10] Y ^* = Y ₀ ^* / Jμ

The next step 306 is to determine the yaw rate deviation ΔY
Is calculated by the following equation.

[Expression 11] ΔY = Y ^* −Y

In the next step 307, a feedback control gain is set. In setting the feedback control gain, the feedback control gain is also corrected using Jμ according to the following equation.

If Jμ ≧ 1, K _p = K _p0 × Jμ, K _d
= K _d0 × Jμ

If Jμ <1, K _p = K _p0 / Jμ, K _d
= K _d0 / Jμ where K _p is a proportional control gain, K _d is a differential control gain, and K _p0 and K _d0 are set values. Step 30
In 7, the controller 11 functions as correction means.

In the next step 308, feedback control (PD) is performed on the yaw rate deviation ΔY obtained in step 306, and the target braking force difference DF of the brake control device is calculated.
^* Is

Calculated by DF ^* = K _P × ΔY + K _d × (ΔY−ΔY _OLD ). Here, ΔY _OLD is Δ one control cycle earlier.
Y.

In the next step 309, the target braking force difference DF
^{From *,} the target braking force F _i ^* (i = 1 to 4) of each wheel is calculated by the following equation.

[Number 15] _{^{F 1 * = F 1old * +}} DF * / 2 F 2 * = F 2old * -DF * / 2 F 3 * = F 3old * + DF * / 2 F 4 * = F 4old * -DF * / 2 It is calculated by: Here, F _iold ^* (i = 1 to 4) is 1
This is F _i ^* before the control cycle.

[0034] In the next step 310, performs the hydraulic control of the brake required to realize the target braking force F _i of each wheel. First, the following equation

Equation 16] P _{w / ci} ^* = by G _i × F _i ^*, the target wheel cylinder pressure ^{_{P w / ci * (i =}} 1~
Find 4). Here G _i is a transform coefficient set for each wheel independently. Next, inlet valves 106, 107, 108 for causing the wheel cylinder pressure _{Pw / ci} ^* to follow a target value.
, 109, 121, 122 and outlet valves 110, 11
1, 112, 113, 123, 124 (see FIG. 2) are set.

In the next step 311, the inlet valve
The controller 11 outputs drive pulses of the motors 106, 107, 108, 109, 121, 122 and outlet valves 110, 111, 112, 113, 123, 124 and an operation signal of the motor 116, and terminates the current control.

Next, the brake fluid pressure control in step 310 of FIG. 4 will be described with reference to the flowchart of FIG.

First, at step 401, the inlet valves 121, 122 and the outlet valves 123, 124 are turned on.
Set the signal. In this case, as shown in FIG. 2, the inlet valves 121 and 122 are closed and the outlet valves 123 and 124 are opened. At this time, the motor 116 operates even when the control is not started, so that the inlet valves 121 and 122 and the outlet valves 123 and 124 are turned on.

In the next step 402, it is determined whether or not the target braking force difference DF ^{* of} the brake control device is zero. Here, if the target braking force difference DF ^* is zero, the motor 116 is operating but the control is not started, that is, the control is in a waiting state, so that the inlet valves 106, 107, 108 and 109 are determined in step 403. And outlet valve
A signal for closing 110, 111, 112, and 113 is set, and a holding state (0 holding) is set. As a result, the inlet valves 106, 107, 108, 109 and the outlet valve 11
Since 0, 111, 112 and 113 are closed, the hydraulic pressure is maintained.

On the other hand, if the target braking force difference DF ^* of the brake control device is not 0 in step 402, the target braking force difference is generated because it is in the control state or the control is to be started. In order to cause the control to proceed, the control proceeds to step 404 and subsequent steps. In step 404, the current wheel cylinder pressure P _{W / Ci} (i = 1 to 4) is estimated. In the present embodiment, the wheel cylinder pressure P _{W / Ci} (i = 1 to 4) is calculated from the previous valve opening time calculated by a method described later.
Shall be estimated.

In the next step 405, the target pressure increase / decrease amount ΔP
Calculate ^* . In the present embodiment, the difference between the current wheel cylinder pressure P _{W / Ci} (i = 1 to 4) obtained in step 404 and the target wheel cylinder pressure P _{W / Ci} ^* (i = 1 to 4) is
Next formula

[Mathematical formula-see original document] Calculated by [Delta] P ^* = _{PW / Ci} ^* -PW _{/ Ci} to obtain the target pressure increase _/ decrease amount [Delta] P ^* .

In the next step 406, the target pressure increase / decrease amount ΔP
The mode of pressure increase / pressure reduction / holding is determined according to ^* . In this determination, in the case of the pressure increase mode, the control is performed in step 40.
7 and thereafter, and in the case of the pressure reduction mode, the control proceeds to step 409 and thereafter, and in the case of the holding mode, the control proceeds to step 403.

In step 407, the valve opening time ZT of the inlet valves 106, 107, 108, 109 at the time of pressure increase is calculated. In this embodiment, the valve opening time ZT is, for example, as shown in FIG.
The master cylinder pressure P _{M / C} and the current wheel cylinder pressure P _{W / Ci} (i = 1 to 4) together with the estimated pressure increase ΔP
Used to calculate _inc .

In calculating the estimated pressure increase amount ΔP _inc , first, the initial value of the valve opening time ZT is set to 5 msec,
Calculate _Pinc . Here, the valve opening time ZT is determined during the control cycle T (for example, 50 msec) by the inlet valves 106, 107,.
108 and 109 are defined as opening times, for example, ZT = 10 msec. Therefore, when ZT is set to 50 msec,
The pressure is increased over the entire period of the control cycle T.

Next, the target pressure increase / decrease amount ΔP ^* and the estimated pressure increase amount ΔP
The difference ΔP _n from P _inc is calculated. Here, ΔP _n = ΔP
^{* When} −ΔP _inc is positive, it is impossible to increase the pressure to the target pressure increase amount with the current valve opening time ZT.
If T has not reached the control cycle T and the pressure increase amount can be further increased, the estimated pressure increase amount ΔP _inc is calculated again after increasing the valve opening time ZT. Here, in this embodiment, it is assumed that the time is increased by 5 msec. Note that the valve opening time ZT
Is equal to the control cycle T, the valve opening time ZT cannot be increased any longer, so ZT = T is determined.

On the other hand, ΔP_nIs negative, the current valve opening
The target pressure increase amount can be sufficiently achieved in the time ZT.
And the current difference ΔP_nAnd the difference before one control cycle
ΔP _n-1Compare with and select the smaller one. Sand
| ΔPn | ≧ | ΔP_n-1If |, the last time the valve was opened
Select the interval ZT. The reason is that the target pressure increase / decrease amount ΔP^*To
| ΔP_n| ≧ | ΔP_n-1| 1 control
Selecting the valve opening time ZT before the cycle is equivalent to the target pressure increase / decrease amount Δ
P^*This is because it can be controlled to a value close to. Conversely, | ΔP_n
| ≦ | ΔP_n-1In the case of |, the current valve opening time ZT is selected.
Select.

In the next step 408, since the pressure is being increased, a signal for closing the outlet valves 110, 111, 112, 113 is set, and the current control is terminated.

If it is determined in step 406 that the mode is the pressure reducing mode, in step 409, the valve opening time GT of the outlet valves 110, 111, 112, and 113 during pressure reduction is calculated. In this embodiment, the valve opening time GT is, for example, as shown in FIG.
Are used together with the current wheel cylinder pressure P _{W / Ci} (i = 1 to 4) to determine the estimated pressure reduction amount ΔP _dec .

In the calculation of the estimated pressure reduction amount ΔP _dec , first, the initial value of the valve opening time GT is set to 5 msec, and the estimated pressure reduction amount ΔP _dec is determined.
Calculate P _dec . Here, the valve opening time GT corresponds to the outlet valves 110 and 111 during the control cycle T (for example, 50 msec).
, 112, 113 are defined as closing time, for example, GT = 10m
sec. Therefore, when GT is set to 50 msec, the pressure is reduced over the entire period of the control cycle T.

Next, the target pressure increase / decrease amount ΔP ^* and the estimated pressure decrease amount Δ
The difference ΔP _{n from} P _dec is calculated. Here, ΔP _n = ΔP ^*
If -ΔP _dec is positive, the valve opening time GT cannot be reduced to the target pressure reduction amount with the current valve opening time GT.
There does not reach the control period T, if further Fuyaseru state pressure reduction amount, increase the valve opening time GT, and estimates pressure increase amount ΔP calculated in _dec again. Here, in this embodiment, it is assumed that it is increased by 5 msec. The valve opening time G
When T is equal to the control cycle T, the valve opening time GT cannot be increased any more, so that GT = T is determined.

On the other hand, [Delta] P _n is in the case of negative, it is determined that the pressure reduction amount of the target in the current opening time GT can be fully achieved, the current difference [Delta] P _n and before one control period Compare the difference ΔPn-1 and select the smaller one. That is, when | ΔP _n | ≧ | ΔP _n−1 |, the previous valve opening time GT is selected. The reason is that, since | ΔP _n | ≧ | ΔP _n−1 | with respect to the target pressure increase / decrease amount ΔP ^* , it is better to select the valve opening time GT one control cycle earlier than the target pressure increase / decrease amount ΔP ^*.
This is because it can be controlled to a value close to P ^* . Conversely, | ΔP _n
If | ≦ | ΔP _n-1 |, the current valve opening time GT is selected.

In the next step 410, since the pressure is being reduced, a signal for closing the inlet valves 106, 107, 108, 109 is set, and the current control is terminated.

If it is determined in the step 406 that the mode is the holding mode, in the step 403, the inlet valves 106 and
107, 108, 109 and outlet valves 110, 111
, 112, and 113 are set, and the control is ended in the holding state (0 holding).

In the vehicle behavior control device according to the present invention, it is desirable to consider whether or not the engine brake affects the vehicle behavior and whether or not inadvertent acceleration of the vehicle occurs. Control to reduce engine brake. FIG. 9 is a flowchart illustrating a processing procedure for performing engine brake reduction control by the present device.
Hereinafter, the procedure will be described.

First, at step 501, it is determined whether or not vehicle behavior control is currently being performed. If control is not being performed, the process is terminated without performing any processing. On the other hand, if the control is being performed, in the next step 502, the influence of the engine brake on the vehicle behavior is determined. The details of the process in this step will be described later.

In the next step 503, it is determined whether or not there is an effect of the engine brake. If so, the idle-up control is performed in the following step 504. On the other hand, if there is no influence, the process ends immediately.

FIG. 10 is a flowchart showing details of the processing procedure in step 502 in FIG. First step 511
Is used to calculate the engine braking force. In the next step 512, the target value of the hydraulic braking force of each wheel (target braking force) F _i ^* (i
= 1 to 4). In the next step 513, the engine braking force and the hydraulic braking force are compared, and the next step
At 514, it is determined whether or not the engine braking force is sufficiently small. If the engine brake is sufficiently small, it is determined in step 515 that the engine brake has no effect.
Otherwise, at step 516, it is determined that there is an effect of the engine brake.

FIG. 11 is a flowchart showing details of the processing procedure in step 511 of FIG. First step 521
In step 522, it is determined whether the accelerator is in the OFF state. If not, the engine braking force is set to 0 in step 522. If the accelerator is off, the driving wheel speed is read from the wheel speed sensor (see FIG. 1) in the next step 523.
In the following step 524, the gear position is set to automatic transmission (AT).
(See FIG. 3). Thereafter, at step 525, the engine braking force is calculated. In this calculation, for example, a graph showing the relationship between the drive wheel speed and the engine braking force for each shift speed as shown in FIG. 13 is used. Note that this graph is stored in the control device according to the present invention in advance.

FIG. 12 is a flowchart showing details of the processing procedure in step 513 of FIG. First step 531
Is the sum of the engine braking force and the target braking force of the wheel ΣF
Compare with _i ^* . Here, if the engine braking force is smaller, it is determined in the next step 532 that the engine braking force is sufficiently small. Conversely, if the engine braking force is larger, it is determined in step 533 that the engine braking force is large.

Next, the operation of the engine brake reduction control using the above-described procedure will be described. As previously mentioned,
If idle-up control is performed when the braking force applied to the drive wheels is solely due to the engine braking force, not only will the braking force applied to the wheels become zero, but the engine driving force will be transmitted to the wheels and the vehicle will accelerate. I will. On the other hand, when the hydraulic brake acts on the drive wheels together with the engine brake, the ratio of the engine brake force to the total brake force decreases, and as a result, the influence of the engine brake fluctuation on the behavior of the vehicle decreases. Also, even if the driving force from the engine is transmitted by idle-up,
If the hydraulic braking force is sufficiently large, the change in the overall braking force is small, and the reduction in deceleration can be reduced.

Further, a signal for instructing idle-up is output from the control device and transmitted to the engine, and then the engine speed increases, and further a phase lag occurs until the resulting driving force is transmitted to the driving wheels. That is, a time difference occurs. Therefore, a sudden change in the driving force after the instruction for idling up is not generated, and it is possible to perform the engine brake reduction control earlier in consideration of this.

Next, as to the ratio of the engine braking force to the total braking force, the engine braking reduction control can be started without disturbing the behavior of the vehicle, as described above. It is based on whether the braking force is equal to the target braking force, that is, whether or not the braking force is 50% of the entire braking force.

Further, by performing the idle-up control under the above-described conditions (procedure), the driving force of the engine is transmitted to the driving wheels after the hydraulic braking force is sufficiently applied. Inadvertent acceleration does not occur.

Therefore, the idle-up control is performed when the hydraulic braking force exceeds the engine braking force, and the control for reducing the engine brake is performed when the engine braking force exceeds the hydraulic braking force. Since the hydraulic brake is more than half of the total braking force, and there is a time difference between the control and the actual increase in the driving force, the behavior of the vehicle is disturbed and the passengers feel uncomfortable. Will not give.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the concept of a vehicle behavior control device according to the present invention.

FIG. 2 is a diagram showing a configuration of a vehicle to which the vehicle behavior control device according to the present invention is applied.

FIG. 3 is a diagram showing an engine unit of a vehicle controlled by the present device.

FIG. 4 is a flowchart showing a processing procedure of vehicle behavior control by the present device.

FIG. 5 is a diagram illustrating characteristics used for calculating an initial value of a target yaw rate in the present apparatus.

FIG. 6 is a flowchart showing a processing procedure of brake fluid pressure control in the present device.

FIG. 7 is a diagram showing characteristics of an actuator model for calculating an opening time of an inlet valve during pressure increase in the present apparatus.

FIG. 8 is a diagram illustrating characteristics of an actuator model for calculating an opening time of an outlet valve when pressure is reduced in the present device.

FIG. 9 is a flowchart showing a processing procedure of engine brake reduction control by the present device.

FIG. 10 is a flowchart showing a processing procedure for determining the effect of the engine brake on the behavior of the vehicle in FIG. 9;

11 is a flowchart showing a processing procedure for calculating an engine braking force in FIG.

FIG. 12 is a flowchart showing a processing procedure for comparing an engine braking force and a hydraulic braking force in FIG. 11;

FIG. 13 is a graph showing a relationship between a driving wheel speed and an engine braking force.

[Explanation of symbols]

10 Vehicle behavior control device 11 Vehicle behavior control controller 12 Engine / AT controller 13 Throttle motor 14 Brake actuator 21 Vehicle behavior control unit 22 Engine brake control unit 23 Various sensors 101 Brake operation unit 101a Brake pedal 101b Booster 101c Master cylinder 101d Reservoir tank 102L , 102R Front wheels 103L, 103R Rear wheels 104L, 104R, 105L, 105R Wheel cylinders 106, 107, 108, 109, 121, 122 Inlet valves 110, 111, 112, 113, 123, 124 Outlet valves 114, 115 Reservoir 116 Motor 117 , 118 Pump 119, 120 Damper chamber 125, 126 Relief valve 128L, 128R, 129L, 129R Wheel speed sensor 130 Steering angle sensor 131 Yaw rate sensor 132 Lateral acceleration sensor 133 Vehicle speed sensor 134 Master cylinder pressure sensor 201 Engine 202 Clutch 203 Automatic transmission 204 Throttle valve 205 Throttle sensor 206 accelerator pedal 207 the accelerator opening sensor 208 throttle controller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B60T 8/24 B60T 8/24 3J058 F term (reference) 3D041 AA30 AA31 AA34 AB01 AD04 AD10 AD18 AD31 AD44 AD47 AD50 AD51 AE04 AE07 AE09 AE31 AE39 AE40 AE41 AF01 AF09 3D045 BB40 CC01 EE21 GG00 GG25 GG26 GG27 3D046 BB32 CC02 GG02 HH00 HH05 HH07 HH08 HH16 HH17 DBH03 DB03 BA06 JJ03 EA00 EA01 EB04 FA10 3G301 JA03 KA11 KB06 KB10 LA01 MA11 NC04 ND01 PA11A PA11Z PF01Z PF03Z PF05A PF05Z PF06Z PF08A PF08Z 3J058 AB39 BA80 CC03 CD06 CD23 DB20 DB21 DB29 FA01

Claims (3)

[Claims] An actual yaw rate detecting means for detecting an actual yaw rate actually generated in a vehicle, and a target yaw rate calculating means for calculating a target yaw rate to be achieved by the vehicle, wherein a deviation between the actual yaw rate and the target yaw rate is calculated. A vehicle behavior control device that controls the behavior of the vehicle in response to the influence of the engine brake; and an impact determination means that determines the effect of the engine brake on the behavior of the vehicle. A vehicle behavior control device, wherein when the determination means determines that the behavior of the vehicle is affected by the engine brake, control is performed to reduce the engine brake. 2. The apparatus according to claim 1, wherein said influence determining means includes: an engine braking force calculating means; a hydraulic braking force calculating means; and a comparing means for comparing the engine braking force with the hydraulic braking force. A vehicle behavior control device, comprising: 3. The apparatus according to claim 2, wherein the influence determining means compares the engine braking force with a hydraulic braking force, and when the engine braking force exceeds the hydraulic braking force, the engine brake is applied to the vehicle. A vehicle behavior control device that determines that the behavior of the vehicle is affected.