JP3502209B2 - Vehicle behavior control device - Google Patents

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 suppressing and reducing undesired behavior such as spin and drift out at the time of turning a vehicle such as an automobile. The present invention relates to a behavior control device that stabilizes behavior.

[0002]

2. Description of the Related Art As one of behavior control devices for controlling the behavior of a vehicle such as an automobile at the time of turning, for example, Japanese Unexamined Patent Publication No. 62-62160.
As described in Japanese Patent No. 253559, when the μ-S characteristic between the road surface and the tire is in a non-linear region, it is determined that the vehicle is at the turning limit, and the output of the engine is reduced or the braking force is applied. Therefore, a device that reduces the vehicle speed and stabilizes the turning behavior of the vehicle has been conventionally known.

According to such a behavior control device, when the vehicle is in the turning limit state, the vehicle speed is automatically reduced, and undesirable behaviors such as spin and drift out are suppressed. It is possible to stabilize the turning behavior of the vehicle as compared with the case where the control is not performed.

[0004]

In the above-mentioned behavior control device, when the turning behavior of the vehicle is stabilized and the μ-S characteristic between the road surface and the tire returns to the linear region, the engine output is reduced to the accelerator pedal. The output corresponding to the pedal depression amount is restored. However, if the degree of increase in engine output at the time of this return, in other words, the degree of increase in driving force is not properly controlled, the driver feels a decline, especially when the friction coefficient of the road surface is high, If the coefficient of friction is low, the behavior of the vehicle may become unstable.

The present invention has been made in view of the above-mentioned problems in the conventional behavior control device, and the main problem of the present invention is that the turning behavior of the vehicle becomes stable and the output of the engine becomes the accelerator pedal. By appropriately controlling the degree of increase in engine output when returning to the output corresponding to the depression amount of the vehicle, it is possible to prevent the driver from feeling a sense of decline and the behavior of the vehicle from becoming unstable. Is.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned main problem is that the behavior of a vehicle that performs torque down control to reduce the engine output and stabilize the vehicle behavior when the vehicle is in the turning limit state. in the control unit, the engine output torque-down control during completion to the amount of depression of the accelerator pedal
Horizontal acceleration of the vehicle when returning to the corresponding output
In addition to estimating the
Estimate the friction coefficient, and use the horizontal direction for the friction coefficient of the road surface.
The vehicle behavior control device is configured to obtain a margin of acceleration in the forward direction, and increase the increase gradient of the engine output as the margin increases. Or a vehicle behavior control device having means for detecting a turning limit state of the vehicle and engine output control means for performing torque down control for reducing an engine output when the turning limit state of the vehicle is detected, The engine output control means detects the substantially horizontal acceleration of the vehicle, and the acceleration and the previous road surface at predetermined time intervals .
Means for determining an estimated road friction coefficient Te in dimensions of acceleration based on the estimated friction coefficient, the means for determining the deviation between the estimated friction coefficient detected acceleration as margin, the torque down control at the end of the engine output return sometimes and means for increasing the increasing gradient of the engine output larger the said margin, the hand for obtaining the estimated friction coefficient of the road surface
The stage decreases the acceleration when the acceleration increases
The weight for the acceleration is greater than
This is achieved by a vehicle behavior control device (structure of claim 2).

According to the above-described structure of the first aspect , the engine output is controlled by depressing the accelerator pedal at the end of the torque down control.
Horizontal direction of the vehicle when returning to the output corresponding to the crowded amount
Acceleration is estimated and the acceleration dimension
The road friction coefficient is estimated, the margin of the horizontal acceleration is determined for the road friction coefficient, the margin is at
The larger the engine output, the larger the gradient of engine output is controlled.Therefore, when the road friction coefficient is high and the margin is high, the engine output is gradually controlled to have a higher gradient of increasing the driver 's output. is prevented to remember sensitive Rutotomoni, the engine output when the low margin low friction coefficient of the road surface
By controlling so that the increasing gradient of is not excessive, it is possible to prevent the behavior of the vehicle from becoming unstable.

[0008]

[0009] In particular, according to the configuration of claim 2, horizontal direction of the acceleration of the vehicle is detected, the acceleration and the front at predetermined time intervals
Dimension of acceleration based on estimated friction coefficient of road surface
The estimated coefficient of friction of the road surface is calculated by comparing the acceleration with the acceleration when the acceleration increases compared to when the acceleration decreases.
The estimated friction coefficient of the road surface is obtained by increasing the weight to be calculated, and the deviation between the estimated friction coefficient and the detected acceleration is obtained as a margin, so the estimated friction coefficient of the road surface is greater than the friction coefficient of the actual road surface. It is calculated to be low, so that the margin at the time of engine output recovery at the end of the torque down control is calculated to be unreasonably low, and the engine output is prevented from being controlled to unreasonably low.

[0010]

According to a preferred mode of the problem solving means of the present invention, in the structure of claim 1 or 2, the torque down control amount is calculated according to the degree of the turning limit state of the vehicle. The engine output is controlled based on the value obtained by subtracting the torque-up control amount from the torque-down control amount when the engine output is restored at the end of the torque-down control, and the torque-up control amount is set to a larger value as the margin is higher. Is configured.

According to another preferred embodiment of the means for solving the problems of the present invention, in the constitution of claim 1 or 2,
A spin state amount indicating the spin state of the vehicle and a drift-out state amount indicating the drift-out state of the vehicle are obtained, and the turning limit state of the vehicle is determined based on the magnitude of these state amounts.

According to yet another preferred aspect of the means for solving the problems of the present invention, in the structure of claim 2, the means for detecting acceleration detects longitudinal acceleration and lateral acceleration of the vehicle, and longitudinal acceleration. And the square root of the lateral acceleration as the substantially horizontal acceleration of the vehicle.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electric control device of one embodiment of a behavior control device according to the present invention.

In FIG. 1, a braking device 10 includes a master cylinder 14 for pumping brake oil from first and second ports in response to a driver's depression of a brake pedal 12, and an oil pressure in the master cylinder. And a hydro booster 16 for increasing the brake oil to a pressure (regulator pressure) corresponding to the above. Master cylinder 1
The first port of 4 is the brake hydraulic control conduit 18 for the front wheels.
Is connected to the brake hydraulic control devices 20 and 22 for the left and right front wheels by means of a brake hydraulic pressure control conduit 26 for the rear wheels which has a proportional valve 24 in the middle of the second port. It is connected to an electromagnetic control valve 28. The control valve 28 is connected by a conduit 30 to a brake hydraulic pressure control device 32 for the left rear wheel and a brake hydraulic pressure control device 34 for the right rear wheel.

The braking device 10 also has an oil pump 40 that pumps the brake oil stored in the reservoir 36 and supplies it as high-pressure oil to the high-pressure conduit 38. The high-pressure conduit 38 is connected to the hydrobooster 16 and the switching valve 44, and an accumulator 46 for accumulating high-pressure oil discharged from the oil pump 40 as accumulator pressure is connected to the middle of the high-pressure conduit 38. There is. As shown in the drawing, the switching valve 44 is also a 3-port 2-position switching type electromagnetic switching valve, and is connected to the hydrobooster 16 by a regulator pressure supply conduit 47 for four wheels.

Brake hydraulic pressure control devices 20 and 22 for the left and right front wheels respectively include wheel cylinders 48FL and 48FR for controlling the braking force to the corresponding wheels, 3-port 2-position switching electromagnetic control valves 50FL and 50FR, and a reservoir. Low-pressure conduit 5 as return passage connected to 36
2 and the switching valve 44. The normally open electromagnetic on-off valves 54FL and 54FR and the normally closed electromagnetic on-off valve 56FL provided in the middle of the regulator pressure supply conduit 53 for the left and right front wheels. And 56 FR. Open / close valve 5
The regulator pressure supply conduits 53 for the left and right front wheels between the 4FL, 54FR and the on-off valves 56FL, 56FR are connected conduits 58FL, 5FL.
It is connected to the control valves 50FL and 50FR by 8FR.

A brake hydraulic control device 32 for the left and right rear wheels,
Reference numeral 34 is a normally-open electromagnetic on-off valve 60RL, 60 provided in the conduit 30 between the control valve 28 and the low-pressure conduit 52.
RR and normally-closed electromagnetic on-off valves 62RL and 62RR, and wheel cylinders 64RL and 64RR that control braking force for the corresponding wheels, respectively.
RL and 64RR are connected to the conduit 30 between the on-off valves 60RL and 60RR and the on-off valves 62RL and 62RR by connection conduits 66RL and 66RR, respectively.

The control valves 50FL and 50FR are respectively the brake hydraulic control conduit 18 for the front wheels and the wheel cylinder 48FL.
And 48FR for communication and wheel cylinder 48FL
, 48FR and the connecting conduits 58FL and 58FR, and the first position shown in the figure, which blocks the brake hydraulic control conduit 18 and the wheel cylinders 48FL and 48FR, and the wheel cylinders 48FL and 48FR, and the connecting conduit 58FL.
And 58FR are switched to a second position where they are connected for communication.

A regulator pressure supply conduit 68 for the left and right rear wheels is connected between the switching valve 44 and the left and right rear wheel control valve 28, and the control valve 28 and the brake hydraulic pressure control conduit 26 for the rear wheels, respectively. The on-off valves 60RL and 60RR are connected in communication with each other, and the on-off valves 60RL and 60RR and the regulator pressure supply conduit 68 are connected.
The first position shown in the figure for shutting off the communication with the brake hydraulic pressure control conduit 26, shutting off the communication between the brake hydraulic pressure control conduit 26 and the on-off valves 60RL, 60RR, and the on-off valves 60RL, 60RR and the regulator pressure supply conduit 6.
It is adapted to switch to a second position where 8 is connected for communication.

The control valves 50FL, 50FR, 28 function as master cylinder pressure shutoff valves, and when these control valves are in the first position shown, the wheel cylinders 48FL, 48.
FR, 64RL, 64RR are connected in communication with conduits 18, 26,
By supplying the master cylinder pressure to each wheel cylinder, the braking force of each wheel is controlled according to the amount of depression of the brake pedal 12 by the driver, and the control valves 50FL,
When 0FR and 28 are in the second position, each wheel cylinder is cut off from the master cylinder pressure.

The switching valve 44 is a wheel cylinder 48F.
The control valves 50FL, 50FR, 28 are switched to the second position and the opening / closing valves 54FL, 54FR serve to switch the hydraulic pressure supplied to the L, 48FR, 64RL, 64RR between the accumulator pressure and the regulator pressure. , 60RL, 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR in the positions shown, when the switching valve 44 is maintained in the first position shown, the wheel cylinders 48FL, 48FR, 64R.
By supplying the regulator pressure to L and 64RR, the pressure in each wheel cylinder is controlled by the regulator pressure, so that the braking pressure of that wheel becomes the depression amount of the brake pedal 12 regardless of the braking pressure of the other wheels. It is controlled in the pressure increasing mode by the corresponding regulator pressure.

Even when each valve is set to the pressure increasing mode by the regulator pressure, when the pressure in the wheel cylinder is higher than the regulator pressure, the oil in the wheel cylinder flows backward and the control mode is the pressure increasing mode. Nevertheless, the actual braking pressure drops.

Also, the control valves 50FL, 50FR, 28 are switched to the second position and the opening / closing valves 54FL, 54FR, 60RL,
When the switching valve 44 is switched to the second position with the 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR in the positions shown, the wheel cylinders 48FL, 48FR, 64R.
By supplying the accumulator pressure to L and 64RR, the pressure in each wheel cylinder is controlled by the accumulator pressure higher than the regulator pressure, and thereby, regardless of the depression amount of the brake pedal 12 and the braking pressure of other wheels. The braking pressure of the wheels is controlled in the pressure increasing mode by the accumulator pressure.

Further, with the control valves 50FL, 50FR, 28 switched to the second position, the on-off valves 54FL, 54FR, 6
0RL and 60RR are switched to the second position, and the on-off valve 56F
When L, 56FR, 62RL, 62RR are controlled to the illustrated state, the pressure in each wheel cylinder is maintained regardless of the position of the switching valve 44, and the control valves 50FL, 50FR, 28 are switched to the second position. Open / close valves 54FL, 54FR, 6
0RL, 60RR and open / close valves 56FL, 56FR, 62RL, 62
When RR is switched to the second position, the pressure in each wheel cylinder is reduced irrespective of the position of the switching valve 44, so that the wheel of that wheel is irrespective of the depression amount of the brake pedal 12 and the braking pressure of other wheels. The braking pressure is controlled in the pressure reduction mode.

Switching valve 44, control valves 50FL, 50FR, 2
8, the on-off valves 54FL, 54FR, 60RL, 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR are controlled by the electric control device 70 as described in detail later. The electric control device 70 includes a microcomputer 72 and a drive circuit 74.
Although the microcomputer 72 is not shown in detail in FIG.
PU), read only memory (ROM), random access memory (RAM), and input / output port device, which are connected to each other by a bidirectional common bus. Good.

In the input / output port device of the microcomputer 72, a signal indicating the vehicle speed V from the vehicle speed sensor 76, a signal indicating the lateral acceleration Gy of the vehicle body from a lateral acceleration sensor 78 provided substantially at the center of gravity of the vehicle body, and a yaw rate sensor 80. A signal indicating the yaw rate γ of the vehicle body, a signal indicating the steering angle θ from the steering angle sensor 82, a signal indicating the longitudinal acceleration Gx of the vehicle body from the longitudinal acceleration sensor 84 provided substantially at the center of gravity of the vehicle body, a wheel speed sensor 86FL ... From 86RR, wheel speeds (circumferential speeds) Vwfl, Vwfr of the left and right front wheels and the left and right rear wheels,
A signal indicating Vwrl and Vwrr is input. The lateral acceleration sensor 78, the yaw rate sensor 80 and the like detect lateral acceleration and the like with the left turning direction of the vehicle being positive, and the longitudinal acceleration sensor 84 detects longitudinal acceleration with the accelerating direction of the vehicle being positive.

The ROM of the microcomputer 72 stores the control flows of FIGS. 2 and 3 and the maps of FIGS. 7 to 9 as will be described later, and the CPU will be described later on the basis of the parameters detected by the various sensors described above. The spin state quantity SS for determining the turning behavior of the vehicle by performing various calculations as described above.
And the drift-out state quantity DS, the turning behavior of the vehicle is estimated based on these state quantities, and the turning behavior is controlled by controlling the braking force of each wheel based on the estimation result,
A signal indicating the spin state amount SS and the drift-out state amount DS is output to the engine control device 100.

As shown in FIG. 6, the engine control unit 100 receives a signal indicating the engine speed Ne from the engine speed sensor 104 of the engine 102, and the throttle opening sensor 106 opens the main throttle 108. A signal indicating φm is input. The main throttle 108 is driven by depressing the accelerator pedal 110. A sub throttle 112 is provided near the main throttle 108, and the sub throttle 112 is driven by an actuator 114.

The engine control unit 100 calculates the target torque Treq of the engine based on the spin state quantity SS and the drift-out state quantity DS according to the control flows of FIGS. 4 and 5 and the maps of FIGS. 10 to 14, and the target torque Treq. The target opening φst of the sub-throttle 112 is calculated based on the above, and a control signal is output to the actuator 114 so that the opening of the sub-throttle 112 becomes the target opening φst, thereby increasing or decreasing the output of the engine. .

Next, the vehicle behavior control routine will be described with reference to the flow charts shown in FIGS. The control according to the flowcharts shown in FIGS. 2 and 3 is started by closing an ignition switch (not shown) and is repeatedly executed at predetermined time intervals.

First, in step 10, the vehicle speed sensor 7
A signal or the like indicating the vehicle speed V detected in 6 is read, and in step 20, the lateral acceleration Gy is deviated from the product V * γ of the vehicle speed V and the yaw rate γ as a deviation Gy-V * γ. That is, the side slip acceleration Vyd of the vehicle is calculated, and in step 30, the side slip velocity Vy of the vehicle body is calculated by integrating the side slip acceleration Vyd.
The slip angle β of the vehicle body is calculated as the ratio Vy / Vx of the vehicle side slip velocity Vy to the vehicle longitudinal velocity Vx (= vehicle speed V).

In step 40, the spin amount SV is calculated as the linear sum K1 * β + K2 * Vyd of the vehicle body slip angle β and the lateral slip acceleration Vyd with K1 and K2 being positive constants, respectively, and in step 50, the yaw rate is calculated. The turning direction of the vehicle is determined based on the sign of γ, and the spin state quantity SS is calculated as SV when the vehicle is turning left and as -SV when the vehicle is turning right, and the spin state is calculated when the calculation result is a negative value. The quantity is zero. The spin amount SV may be calculated as a linear sum of the vehicle body slip angle β and its differential value βd.

In step 60, the target yaw rate γ is calculated according to the following equation 1 using Kh as a stability factor.
In addition to calculating c, the reference yaw rate γt is calculated according to the following equation 2 using T as a time constant and s as a Laplace operator. The target yaw rate γc may be calculated in consideration of the lateral acceleration Gy of the vehicle in order to consider the dynamic yaw rate.

[0035]

## EQU1 ## γ c = V * θ / (1 + Kh * V ² ) * H

## EQU2 ## γt = γc / (1 + T * s)

In step 70, the drift-out amount DV is calculated according to the following equation (3). The drift-out amount DV may be calculated according to the following equation 4 with H as the wheel base.

[0037]

## EQU3 ## DV = (γt−γ)

## EQU4 ## DV = H * (γt−γ) / V

In step 80, the turning direction of the vehicle is judged based on the sign of the yaw rate γ, and the drift-out state quantity DS is calculated as DV when the vehicle is turning left and is calculated as -DV when the vehicle is turning right. When the calculation result is a negative value, the drift-out state quantity is 0.

At step 90, the spin state quantity SS
The slip ratio target value Rssfo of the front wheel on the outside of the turning is calculated from the map corresponding to the graph shown in FIG. 7 based on the above, and in step 100, it corresponds to the graph shown in FIG. 8 based on the drift-out state quantity DS. From the map, the slip ratio target value Rsall of the entire vehicle is calculated.

In step 110, the target slip ratios Rsfo, Rsfi, and Rsro of the front wheel on the outer side of the turn, the front wheel on the inner side of the turn, the rear wheel on the outer side of the turn, and the rear wheel on the inner side of the turn Rsfo, Rsfi, and Rsro are set as Ksri as the distribution rate of the rear wheel on the inside of the turn. , Rsri are calculated.

## EQU00005 ## Rsfo = Rssfo Rsfi = 0 Rsro = (Rsall-Rssfo) * (100-Ksri) / 1
00 Rsri = (Rsall-Rssfo) * Ksri / 100

In step 120, the turning direction of the vehicle is determined based on the sign of the yaw rate γ to identify the inner and outer turning wheels, and the final target slip ratio Rsi (i = fr, fl, rr, rl) are calculated. That is, when the final target slip ratio Rsi is a left turn and a right turn of the vehicle, the following equations 6 and 7 are given respectively.
Sought according to.

[0042]

[Equation 6] Rsfr = Rsfo Rsfl = Rsfi Rsrr = Rsro Rsrl = Rsri

[Equation 7] Rsfr = Rsfi Rsfl = Rsfo Rsrr = Rsri Rsrl = Rsro

In step 130, it is judged whether all final target slip ratios Rsi are 0, that is, whether the behavior control is unnecessary or not. Returning to step 10, when a negative determination is made, the target wheel speed Vwti of each wheel is calculated in step 140 using Vb as the reference wheel speed (for example, the wheel speed of the front wheel on the inside of the turn) according to the following equation 8.

## EQU8 ## Vwti = Vb * (100-Rsi) / 100

In step 150, Vwid is the wheel acceleration of each wheel (differential value of Vwi), and Ks is a positive constant coefficient, and the target slip amount SP of each wheel is calculated according to the following equation (9).
i is calculated, and in step 160, the duty ratio Dri of each wheel is calculated from the map corresponding to the graph shown in FIG.
Is calculated.

[Equation 9] SPi = Vwi-Vwti + Ks * (Vwid-Gx)

Further, at step 170, the switching valve 44
Is switched to the second position to introduce the accumulator pressure, and the control signal is output to the control valves 28, 50FR to 50RL of the wheels corresponding to the wheels whose final target slip Rsi is not 0. The control valve is switched and set to the second position. Further, the control signal corresponding to the duty ratio Dri is output to the opening / closing valve of each wheel to control the supply / discharge of the accumulator pressure to / from the wheel cylinders 48FR to 48RL, thereby controlling the braking pressure of each wheel.

In this case, when the duty ratio Dri is a value between the negative reference value and the positive reference value, the upstream side opening / closing valve is switched to the second position and the downstream side opening / closing valve is set to the first position. By being held in the position, the pressure in the corresponding wheel cylinder is held, and when the duty ratio is equal to or greater than the positive reference value, the upstream and downstream on-off valves are controlled to the positions shown in FIG. The pressure in the wheel cylinder is increased by supplying the accumulator pressure to the corresponding wheel cylinder, and when the duty ratio is equal to or less than the negative reference value, the upstream and downstream opening / closing valves are in the second position. When the brake oil in the corresponding wheel cylinder is changed to the low pressure conduit 52,
And the pressure in the wheel cylinder is reduced.

When the pressure in the wheel cylinder is increased, the open / close valve on the upstream side is opened / closed according to the duty ratio, and when the pressure in the wheel cylinder is reduced, the open / close valve on the downstream side is opened / closed according to the duty ratio. It is opened and closed. As a result, the increasing / decreasing gradient of the pressure in the wheel cylinder becomes larger as the duty ratio becomes larger.

Next, the torque down control routine in the illustrated embodiment will be described with reference to the flow chart shown in FIG. The control according to the flowchart shown in FIG. 4 is executed by interruption every predetermined time.

First, at step 210, a signal indicating the spin state quantity SS is read, and then step 220
At this time, the torque down amount Tdwns based on the spin is calculated from the map corresponding to the graph shown in FIG. 10 based on the spin state amount SS, and at step 230, based on the drift out state amount DS shown in FIG. The torque down amount Tdwnd based on the drift-out is calculated from the map corresponding to the generated graph.

In step 240, it is determined whether Tdwns> Tdwnd by comparing the two torque reduction amounts. If a positive determination is made, step 250 is performed.
At this time, when the reference value Tdwno of the torque down control amount is set to Tdwns and a negative determination is made, step 260
At this time, the reference value Tdwno is set to Tdwnd.

In step 270, the torque down control amount Tdwnctl is calculated according to the following equation 10. In equation 10, MAX means selecting the larger value in parentheses, Tdwnctl (n-1) is the torque down control amount one cycle before, and Tuplim is the torque up control amount. is there.

[Equation 10] Tdwnctl = MAX [0, MAX [Tdwnctl (n
-1) -Tuplim, Tdwno]]

In step 280, the engine output Tal is calculated from the map corresponding to the graph shown in FIG. 12 based on the engine speed Ne and the opening .phi.m of the main throttle.
l is calculated, and in step 290, the following equation 11
The target torque value Treq is calculated in accordance with the above. The engine output Tall may be calculated based on the engine speed Ne, the opening φ of the main throttle, and the transmission reduction ratio.

[Equation 11] Treq = (1-Tdwnctl) * Tall

In step 300, the target opening φst of the sub-throttle 112 is calculated from the map corresponding to the graph shown in FIG. 13 based on the engine speed Ne and the torque target value Treq, and in step 310. By outputting a control signal to the actuator 114 so that the opening of the sub throttle 112 becomes the target opening φst, the output of the engine is controlled to increase or decrease.

Next, referring to the flow chart shown in FIG. 5, the torque-up control amount Tupli in the illustrated embodiment is shown.
The m operation routine will be described. The control according to the flowchart shown in FIG. 5 is also executed by interruption every predetermined time.

In step 410 of this routine, a signal indicating the longitudinal acceleration Gx is read, and in step 420, the horizontal acceleration Gxy of the vehicle is calculated from the longitudinal acceleration Gx and the lateral acceleration Gy according to the following equation 12. Calculated as the root sum of squares.

[Equation 12] Gxy = (Gx ² + Gy ² ) ^1/2

In step 430, it is judged whether or not the estimated friction coefficient μg of the road surface calculated in step 460, which will be described later, is smaller than the horizontal acceleration Gxy. If a positive judgment is made, step 440 is executed. At the coefficient K
Is set to 1 and a negative determination is made, the coefficient K is set to 0.01 in step 450.

In step 460, μg (n-1) is applied to the road surface.
As the previous value of the estimated friction coefficient μg of, the estimated friction coefficient μg of the road surface becomes the acceleration dimension according to the following equation 13.
It is calculated Te.

[Equation 13] μg = (1-K) * μg (n-1) + K * Gxy

In step 470, the horizontal acceleration Gxy with respect to the estimated friction coefficient μg of the road surface is calculated according to the following equation (14).
Is calculated, and in step 480, the torque-up control amount Tuplim is calculated from the map corresponding to the graph shown in FIG. 14 based on the margin Gmgn.

## EQU14 ## Gmgn = μg-Gxy

Thus, according to this embodiment, when the turning behavior of the vehicle is in a stable state, the affirmative determination is made in step 130, and the process directly returns to step 10. Therefore, in this case, steps 140 to 17 are executed.
The behavior control based on 0 is not executed, whereby the braking pressure of each wheel is controlled according to the amount of depression of the brake pedal 12 by the driver.

When the turning behavior of the vehicle is stable, the spin state quantity SS and the drift-out state quantity D
Since S is 0, the torque down amounts Tdwns and Tdwnd calculated in steps 220 and 230 respectively become 0, and the torque down control amount Tdwnctl also becomes 0. Therefore, in this case, the torque down control of the engine is performed. Not done

On the other hand, when the turning behavior of the vehicle is unstable, a negative determination is made in step 130, the target wheel speed Vwti of each wheel is calculated in step 140, and step 150 is executed. At 170 to 170, the braking force of each wheel is controlled so that the wheel speed of each wheel becomes the target wheel speed Vwti, whereby the turning behavior of the vehicle is stabilized.

In other words, the spin state quantity is calculated based on the vehicle body slip angle β and the like, and the drift out state quantity is calculated based on the actual yaw rate γ and the like to obtain both the spin state quantity and the drift out state quantity. Based on this, the braking force of each wheel is controlled, thereby reducing their unstable behavior in both the spin state and the drift-out state.

When the turning behavior of the vehicle is unstable, the torque reduction amounts Tdwns and Tdwnd are calculated in steps 220 and 230, respectively, and the torque reduction control amount Tdwnctl is calculated in steps 240 to 270. , Steps 280 to 300, the target opening φst of the sub-throttle 112 according to the torque down control amount.
Is calculated, and the torque reduction control is executed by controlling the opening of the sub-throttle to the target opening in step 310, which also reduces the spin state or drift-out state of the vehicle. .

In addition, in the process in which the behavior of the vehicle becomes more stable than the unstable state, steps 220 and 230 are performed.
The torque down amounts Tdwns and Tdwnd calculated in step 270 are gradually decreased, and the torque down control amount Tdwnctl calculated in step 270 is also gradually decreased, whereby the opening of the sub-throttle is gradually increased. Due to this, the output of the engine is gradually restored.

In particular, according to the illustrated embodiment, step 4
In step 20, the horizontal acceleration Gxy of the vehicle is calculated, and in steps 430 to 460, the acceleration based on the horizontal acceleration is calculated .
The estimated friction coefficient μg of the road surface is calculated by the dimension, and the margin Gmgn of the horizontal acceleration Gxy with respect to the estimated friction coefficient μg is calculated in step 470. The higher the margin, the larger the torque-up control amount Tuplim. Therefore, the higher the margin at the time of returning the engine output at the end of the torque down control, the higher the gradient of increase in the engine output, so that the engine output is restored without excess or deficiency.

Also according to the illustrated embodiment, step 4
In step 30, it is determined whether or not the horizontal acceleration is in the increasing process. When it is determined that the horizontal acceleration is in the increasing process, the coefficient K is set to 1 in step 440, and it is in the decreasing process. Is determined, the coefficient K is set to a value much smaller than 1 in step 450, and the estimated friction coefficient μg is calculated in accordance with equation 13 in step 460. Therefore, the estimated friction coefficient μg is actually calculated. Is calculated to be lower than the friction coefficient of the road surface, and thereby the increase gradient of the engine output is reliably prevented from being unduly reduced due to the calculation of the margin Gmgn at the time of engine output restoration being low.

Although the present invention has been described in detail above with reference to specific embodiments, the present invention is not limited to the above-mentioned embodiments, and various other embodiments within the scope of the present invention. It will be apparent to those skilled in the art that

For example, in the above-mentioned embodiment, the braking force of each wheel is controlled by the wheel speed feedback, but the braking force of each wheel is controlled by the pressure feedback about the pressure in the wheel cylinder. May be done.

In the above-described embodiment, the drift-out state is determined based on the drift-out state amount calculated based on the yaw rate deviation. However, the drift-out state is determined based on the actual yaw rate or the yaw rate. The reference steering angle may be obtained from the lateral acceleration or the like, and the determination may be made based on the deviation between the reference steering angle and the actual steering angle.

[0070]

As more is apparent the foregoing description, according to the present invention, when the high high margin coefficient of friction road surface, since it is controlled so that the increasing gradient of the engine output increases, the engine It is possible to prevent the driver from feeling a sense of decline due to insufficient output of the vehicle, and if the friction coefficient of the road surface is low and the margin is low , the increase gradient of the engine output may become excessive. It is possible to prevent the behavior of the vehicle from becoming unstable due to the excessive engine output.

[0071] In particular, according to the configuration of claim 2, horizontal direction of the acceleration of the vehicle is detected, the acceleration and the front at predetermined time intervals
Dimension of acceleration based on estimated friction coefficient of road surface
The estimated coefficient of friction of the road surface is calculated by comparing the acceleration with the acceleration when the acceleration increases compared to when the acceleration decreases.
The estimated friction coefficient of the road surface is obtained by increasing the weight to be calculated, and the deviation between the estimated friction coefficient and the detected acceleration is obtained as a margin, so the estimated friction coefficient of the road surface is greater than the friction coefficient of the actual road surface. It is calculated to be low, so that it is possible to prevent the margin at the time of returning the engine output at the end of the torque down control from being calculated unreasonably low and controlling the engine output unreasonably low.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electric control device of an embodiment of a behavior control device according to the present invention.

FIG. 2 is a flowchart showing the first half of a behavior control routine of the embodiment.

FIG. 3 is a flowchart showing the latter half of the behavior control routine of the embodiment.

FIG. 4 is a flowchart showing a torque down control routine of the embodiment.

FIG. 5 is a flowchart showing a torque-up control amount calculation routine of the embodiment.

FIG. 6 is an explanatory diagram showing an air supply system of the engine.

FIG. 7 is a graph showing a relationship between a spin state amount SS and a slip ratio target value Rssfo of a front wheel on the outside of turning.

FIG. 8 is a graph showing a relationship between a drift-out state quantity DS and a slip ratio target value Rsall of the entire vehicle.

FIG. 9: Target slip amount SPi and duty ratio D of each wheel
It is a graph which shows the relationship with ri.

FIG. 10 is a graph showing a relationship between a spin state amount SS and a torque reduction amount Tdwns.

FIG. 11 is a graph showing a relationship between a drift-out state amount DS and a torque down amount Tdwnd.

FIG. 12 is a graph showing a relationship between an engine speed Ne, a main throttle opening φm, and an engine output Tall.

FIG. 13 is a graph showing a relationship between an engine speed Ne, a target torque value Treq of the engine, and a sub throttle opening φs.

FIG. 14 is a graph showing a relationship between a margin Gmgn of horizontal acceleration Gxy and a torque-up control amount Tuplim.

[Explanation of symbols]

10 ... Braking device 14 ... Master cylinder 16 ... Hydro booster 20, 22, 32, 34 ... Brake hydraulic pressure control device 28, 50FL, 50FR ... Control valve 44 ... Switching valve 44FL, 44FR, 64RL, 64RR ... Wheel cylinders 70 ... Electric control device 78 ... Lateral acceleration sensor 84 ... longitudinal acceleration sensor 100 ... Engine control device 102 ... engine 108 ... Main throttle 112 ... Sub throttle

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-6-317196 (JP, A) JP-A-6-229268 (JP, A) JP-A-6-278635 (JP, A) JP-A-6- 229271 (JP, A) JP 5-112159 (JP, A) JP 7-127492 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 29/00-29 / 06 F02D 41/00-41/40 B60K 41/00-41/28

Claims (2)

(57) [Claims] 1. A vehicle is at the behavior control device of a vehicle which performs torque-down control to stabilize the vehicle behavior by reducing the engine output becomes the turning limit state, the accelerator pedal of the engine output torque-down control during completion The amount of depression
The horizontal acceleration of the vehicle when returning to the corresponding output
In addition to estimating the road surface,
Estimate the friction coefficient, and the horizontal direction to the friction coefficient of the road surface
The vehicle behavior control device is characterized in that the acceleration margin of the vehicle is calculated, and the increase gradient of the engine output is increased as the margin is increased . 2. A vehicle behavior control device having means for detecting a turning limit state of a vehicle and engine output control means for performing a torque down control for reducing an engine output when the turning limit state of the vehicle is detected. The engine output control means detects the substantially horizontal acceleration of the vehicle and the acceleration and the previous road surface at predetermined time intervals.
Means for determining an estimated road friction coefficient Te in dimensions of acceleration based on the estimated friction coefficient, the means for determining the deviation between the estimated friction coefficient detected acceleration as margin, the torque down control at the end of the engine output A means for increasing the gradient of the engine output as the margin is increased at the time of restoration to obtain an estimated friction coefficient of the road surface.
The stage decreases the acceleration when the acceleration increases
The weight for the acceleration is greater than
A vehicle behavior control device characterized by being configured as described above.