JP2518445B2 - Vehicle turning control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention can quickly reduce the driving torque of the engine in accordance with the lateral acceleration generated when the vehicle turns, and can perform the turning operation easily and safely. The present invention relates to a turning control device for a vehicle.

<Prior Art> Since a centrifugal force corresponding to a lateral acceleration in a direction perpendicular to the traveling direction is generated in a vehicle running on a turning circuit, if the traveling speed of the vehicle with respect to the turning circuit is too high, There is a risk that the vehicle body will skid beyond the limit of the grip force.

In such a case, in order to properly lower the output of the engine and safely drive the vehicle with a turning radius corresponding to the turning circuit,
Especially when the exit of the turning circuit cannot be confirmed, or when the radius of curvature of the turning circuit is gradually decreasing,
Extremely advanced driving technology is required.

In a general vehicle having a so-called under-steering tendency, it is necessary to gradually increase the steering amount as the lateral acceleration applied to the vehicle increases. When the lateral acceleration exceeds a certain value peculiar to each vehicle, steering As the amount increases sharply, safe turning is difficult or impossible, as described above. It is well known that this tendency becomes remarkable especially in a front engine front-wheel drive type vehicle with a strong tendency to understeer.

For this reason, the lateral acceleration of the vehicle is detected and the engine output is forcibly reduced before the turning limit at which the vehicle becomes difficult or unable to turn, regardless of the accelerator pedal depression amount by the driver. An output control device configured to do so is conceivable, and the driver can select traveling using this output control device and normal traveling in which the output of the engine is controlled according to the depression amount of the accelerator pedal, as needed. Have been announced.

<Problems to be Solved by the Invention> When the traveling safety of a vehicle is taken into consideration, the lateral acceleration of the vehicle is detected and is related to the amount of depression of the accelerator pedal by the driver before the vehicle becomes difficult or unable to turn. It is desirable that the vehicle be equipped with an output control device that forcibly reduces the output of the engine.

However, conventionally, the target acceleration in the front-rear direction is set by the lateral acceleration, and a constant load / load torque is added to this acceleration as the resistance of the road surface. Here, the actual load torque at the time of turning includes not only the rolling resistance line segment but also the cornering drag, which is the resistance to the centrifugal force direction. In the past, however, the cornering drag changes according to the lateral acceleration. Not, or the change was small.

However, when actually measured, it was found that the change became larger as the lateral acceleration became larger, and the amount of change could not be ignored.

The present invention has been made based on such a viewpoint, and an object thereof is to provide a turning control device for a vehicle capable of setting a target drive torque in consideration of cornering drag at the time of turning. .

<Means for Solving the Problems> A turning control device for a vehicle according to the present invention is a torque control means for reducing a driving torque of an engine independently of a driver's operation, and a vehicle according to a magnitude of lateral acceleration during turning. Is set to a target acceleration in the front-rear direction, the target drive torque is set by adding the load load torque to the acceleration, and the torque control means is controlled so that the drive torque of the engine becomes the target drive torque. In a vehicle including a turning control unit, the road load torque includes a rolling resistance component and a cornering drag component that changes according to the lateral acceleration.

<Operation> The load load torque at the time of turning includes not only the rolling resistance component but also the cornering drag component, and this cornering drag becomes larger as the lateral acceleration becomes larger. Therefore, in the present invention, the target drive torque is set by taking into account the cornering drag that changes according to the lateral acceleration without ignoring the cornering drag component, so that more appropriate control can be performed.

<Embodiment> As shown in FIG. 1 showing the concept of an embodiment in which the vehicle output control method according to the present invention is applied to a front-wheel drive type vehicle and FIG. 2 showing the schematic structure of the vehicle, as shown in FIG. Combustion chamber
In the middle of an intake pipe 13 connected to 12, the opening degree of an intake passage 14 formed by the intake pipe 13 is changed to
A throttle body 16 incorporating a throttle valve 15 for adjusting the amount of intake air supplied therein is interposed. First
As shown in FIG. 3 and FIG. 3 showing an enlarged cross-sectional structure of a portion of the throttle body 16 having a cylindrical shape,
16 has a throttle shaft 17 with the throttle valve 15 fixed integrally.
Are rotatably supported at both ends. An accelerator lever 18 and a throttle lever 19 are coaxially fitted to one end of the throttle shaft 17 projecting into the intake passage 14.

A bush 21 and a spacer 22 are interposed between the throttle shaft 17 and the cylinder portion 20 of the accelerator lever 18, so that the accelerator lever 18 is rotatable with respect to the throttle shaft 17. Further, a washer 23 and a nut 24 attached to one end of the throttle shaft 17 prevent the accelerator lever 18 from coming off from the throttle shaft 17 beforehand. Also, a cable receiver 25 integrated with the accelerator lever 18 is provided.
, An accelerator pedal 26 operated by the driver is connected via a cable 27, and the accelerator lever 18 rotates with respect to the throttle shaft 17 according to the amount of depression of the accelerator pedal 26. .

On the other hand, the throttle lever 19 is fixed integrally with the throttle shaft 17, so that by operating the throttle lever 19, the throttle valve 15
Rotate with. A collar 28 is fitted coaxially and integrally with the cylinder portion 20 of the accelerator lever 18, and the tip of the throttle lever 19 is engaged with a claw 29 formed on a part of the collar 28. A stopper 30 is formed.
The pawl portion 29 and the stopper 30 are engaged with each other when the throttle lever 19 is turned in the direction in which the throttle valve 15 opens or the accelerator lever 18 is turned in the direction in which the throttle valve 15 closes. Is set in a proper positional relationship.

Between the throttle body 16 and the throttle lever 19, a torsion coil spring 31 for pressing the stopper 30 of the throttle lever 19 against the claw portion 29 of the accelerator lever 18 to urge the throttle valve 15 in the opening direction is provided between the throttle shaft 17 and the throttle shaft 17. It is mounted coaxially with the throttle shaft 17 via a pair of cylindrical spring receivers 32 and 33 fitted to the throttle shaft 17. Also, between the stopper pin 34 protruding from the throttle body 16 and the accelerator lever 18, the claw portion 29 of the accelerator lever 18 is pressed against the stopper 30 of the throttle lever 19 to urge the throttle valve 15 in the closing direction, and the accelerator A torsion coil spring 35 for giving a detent feeling to the pedal 26 is mounted on the cylinder portion 20 of the accelerator lever 18 via the collar 28 so as to be coaxial with the throttle shaft 17.

The distal end of the throttle lever 19 is connected to the distal end of a control rod 38 whose base end is fixed to the diaphragm 37 of the actuator 36. A pressure chamber 39 formed in the actuator 36 has a stopper 30 of the throttle lever 19 together with the torsion coil spring 31 and a claw portion of the accelerator lever 18.
A compression coil spring 40 that urges the throttle valve 15 in the direction of opening by pressing the same against the 29 is incorporated. Then, the spring force of the torsion coil spring 35 is set to be larger than the sum of the spring forces of these two springs 31 and 40, whereby the accelerator pedal 26 is depressed or the pressure in the pressure chamber 39 is set to the above-mentioned value. The throttle valve 15 is prevented from opening unless a negative pressure larger than the sum of spring forces of the three springs 31 and 40 is applied.

A surge tank 41 connected to the downstream side of the throttle body 16 and forming a part of the intake passage 14 has a connection pipe 42
The vacuum tank 43 is in communication with the fuel tank, and between the vacuum tank 43 and the connection pipe 42, a check valve 44 that allows only the movement of air from the vacuum tank 43 to the surge tank 41 is interposed. I have. As a result, the pressure in the vacuum tank 43 is set to a negative pressure substantially equal to the minimum pressure in the surge tank 41.

The inside of the vacuum tank 43 and the actuator 36
The pressure chamber 39 is in communication with the pressure chamber 39 via a pipe 45, and a non-energized first torque control solenoid valve 46 is provided in the middle of the pipe 45. In other words, the torque control solenoid valve 46 has a plunger 47 so as to close the pipe 45.
A spring 49 for urging the valve seat 48 against the valve seat 48 is incorporated.

Further, a pipe 50 communicating with the intake passage 14 upstream of the throttle valve 15 is connected to a pipe 45 between the first torque control solenoid valve 46 and the actuator 36. In the middle of the pipe 50, a second torque control solenoid valve 51 which is open when not energized is provided. That is, a spring 53 for urging the plunger 52 to open the pipe 50 is incorporated in the torque control solenoid valve 51.

The two torque control solenoid valves 46 and 51 include an electronic control unit 54 (hereinafter, referred to as an electronic control unit 54) for controlling the operating state of the engine 11.
ECUs) are connected to each other, and duty on / off of energization to the torque control solenoid valves 46 and 51 is controlled based on a command from the ECU 54.
In this embodiment, the torque control means of the present invention is constituted by these components as a whole.

For example, when the duty ratio of the torque control solenoid valves 46, 51 is 0%, the pressure chamber 39 of the actuator 36 becomes an atmospheric pressure substantially equal to the pressure in the intake passage 14 upstream of the throttle valve 15, and the throttle valve 15 Is the accelerator pedal 26
One-to-one correspondence with the depression amount of. Conversely, when the duty ratio of the torque control solenoid valves 46 and 51 is 100%, the pressure chamber 39 of the actuator 36 has a negative pressure substantially equal to the pressure in the vacuum tank 43, and the control rod 38 is at the left in FIG. As a result of being lifted diagonally upward, the throttle valve 15
It is closed irrespective of the amount of depression of 26, and the driving torque of the engine 11 is forcibly reduced. In this way, by adjusting the duty ratio of the torque control solenoid valves 46, 51, the opening degree of the throttle valve 15 is changed regardless of the depression amount of the accelerator pedal 26, and the drive torque of the engine 11 is arbitrarily adjusted. can do.

The ECU 54 includes a crank angle sensor 55 attached to the engine 11 to detect the engine speed, and a throttle body 16
A throttle opening sensor 56 attached to the throttle valve 19 for detecting the opening of the throttle lever 19 and an idle switch 57 for detecting the fully closed state of the throttle valve 15 are connected, and these crank angle sensor 55, throttle opening sensor 56 and Output signals from the idle switch 57 are sent.

Further, a torque calculation unit (hereinafter, referred to as TCL) 58 for calculating a target drive torque of the engine 11 is attached to the throttle body 16 together with the throttle opening sensor 56 and the idle switch 57, and is attached to the accelerator lever 18. An accelerator opening sensor 59 that detects the opening, front wheel rotation sensors 62 and 63 that detect the rotational speeds of the pair of left and right front wheels 60 and 61 that are driving wheels, and a pair of left and right rear wheels that are driven wheels,
Rear wheel rotation sensors 66, 67 that detect the rotation speed of 65
And a steering angle sensor 70 that detects the turning angle of the steering shaft 69 when turning based on the straight traveling state of the vehicle 68, and output signals from these sensors 59, 62, 63, 66, 67, 70 are respectively Sent.

The ECU 54 and the TCL 58 are connected via a communication cable 71, and the ECU 54 sends to the TCL 58 information on the operating state of the engine 11, such as the engine speed and the detection signal from the idle switch 57, as well as the intake air amount. Can be On the contrary, from TCL58 this TCL58
Is transmitted to the ECU 54.

As shown in FIG. 4 that represents the general flow of control according to the present embodiment, a target driving torque T _OS of the engine 11 in the case of performing the slip control in the present embodiment, comparison of the friction coefficient as a dry road, etc. High road surface (hereinafter referred to as high μ road)
Target drive torque T of the engine 11 when turning control is performed at
_OH and the target drive torque _TOL of the engine 11 when turning control is performed on a road surface having a relatively low friction coefficient such as a frozen road or a wet road (hereinafter, referred to as a low μ road). TCL58 always calculates in parallel, these three target drive torque
The optimal final target drive torque T _O is selected from T _OS , T _OH , and T _OL so that the drive torque of the engine 11 can be reduced as necessary.

Specifically, the control program of the present embodiment is started by turning on an ignition key (not shown). At M1, first, an initial value δ _{m (0)} of the steering shaft turning position is read, and various flags are reset or reset. Initial settings such as the start of counting of the main timer every 15 milliseconds, which is the control sampling period, are performed.

Then, based on the detection signals from various sensors in M2
The TCL 58 calculates the vehicle speed V and the like, and subsequently, the steering shaft 69
It is at the neutral position δ _M of the M3 learning correction. Neutral position [delta] _M of the steering shaft 69 of the vehicle 68, wherein at the initial value [delta] _{m (0)} is read each time the ignition key turned on, the initial value [delta] _{m (0)} is the vehicle 68 will be described later straight The learning correction is performed only when the traveling condition is satisfied, and the initial value Δm ₍₀₎ is learned and corrected until the ignition key is turned off.

Then, TCL 58 calculates a target driving torque T _OS for performing slip control for regulating the driving torque of the engine 11 based on the rotational difference between the rear wheel 64 and 65 and front wheels 60 and 61 at M4, the M5 The target drive torque T _OH of the engine 11 when the turning control is performed on the high μ road is calculated by the same manner, and similarly, the target driving torque T _OL of the engine 11 when the turning control is performed on the low μ road by M6. Are sequentially calculated.

Then, at M7, TCL58 determines these target driving torques T _OS ,
After selecting the optimal final target drive torque T _O from T _OH and T _OL by the method described below, the ECU 54 uses a pair of torque control solenoid valves so that the drive torque of the engine 11 becomes the final target drive torque T _O. The duty ratios of 46 and 51 are controlled so that the vehicle 68 can be comfortably and safely driven.

In this way, the drive torque of the engine 11 is controlled at M8 until the countdown of the main timer is completed, and thereafter, the countdown of the main timer is restarted at M9, and the steps from M2 to M9 are performed by the ignition. It repeats until the key is turned off.

The reason why the neutral position δ _M of the steering shaft 69 is learned and corrected in the step of M3 is that steering is performed when the toe-in adjustment of the front wheels 60, 61 is performed during maintenance of the vehicle 68 or due to secular change such as wear of steering gears not shown. Turning amount of shaft 69 and front wheels 60,6 as steering wheels
Deviation occurs between the actual steering angle [delta] of 1, and there is a possible neutral position [delta] _M of the steering shaft 69 would change.

As shown in FIG. 5 showing a procedure for learning correct neutral position [delta] _M of the steering shaft 69, TCL 58 based on the detection signal from the rear wheel rotation sensor 66 and 67, the following expression vehicle speed V at C1 (1 ).

However, in the above equation, V _RL and V _RR are the peripheral speeds of the pair of left and right rear wheels 64 and 65, respectively.

Next, the TCL 58 calculates the peripheral speed difference | V _RL −V _RR | of the pair of left and right rear wheels 64 and 65 at C2 (hereinafter, this difference is referred to as a rear wheel speed difference).

Thereafter, the TCL 58 determines at C3 whether the vehicle speed V is greater than a preset threshold value _VA . This operation is
If the speed does not reach a certain level, the rear wheel speed difference due to steering
It is necessary because V _RL −V _RR | etc. cannot be detected.
The threshold value _VA is appropriately set, for example, at 20 km / h, based on the running characteristics of the vehicle 68 and the like through experiments.

When it is determined that the vehicle speed V is equal to or greater than the threshold value V _A is the rear wheel speed difference TCL58 is at C4 | V _RL -V _RR | is set in advance, than such threshold value V _B, for example every hour 0.1km It is determined whether or not it is small, that is, whether or not the vehicle 68 is in a straight traveling state. Here, not to the threshold V _B and hourly 0km, when left and right rear wheels 64 and 65 are not equal the tire pressure, vehicle 68 is rear wheels 64 and 65 of the pair despite running straight This is because the peripheral velocities V _RL and V _RR are different.

Rear wheel speed difference is determined in step C4 | V _RL -V _RR | is threshold V _B
If it is determined that the following, the TCL 58 is the same as the previous steering shaft turning position δ _{m (n-1)} at C5 where the current steering shaft turning position δ _{m (n)} detected by the steering angle sensor 70 Is determined. At this time, it is desirable to set the turning detection resolution of the steering shaft 69 by the steering angle sensor 70 to, for example, about 5 degrees so as not to be affected by the shake of the driver or the like.

If it is determined in this step C5 that the current steering axis turning position δ _{m (n)} is the same as the previous steering axis turning position angle δ _{m (n-1)} , the TCL58 determines the current vehicle position at C6. It is determined that 68 is in the straight traveling state, and the counting of the learning timer (not shown) incorporated in this TCL 58 is started, and this is continued for, for example, 0.5 seconds.

Next, the TCL 58 determines in C7 whether or not 0.5 seconds have elapsed from the start of the counting of the learning timer, that is, whether or not the straight traveling state of the vehicle 68 has continued for 0.5 seconds. In this case, since 0.5 seconds have not elapsed since the start of the counting of the learning timer at the beginning of the running of the vehicle 68, the steps from C1 to C7 are repeated at the beginning of the running of the vehicle 68.

When it is determined that 0.5 seconds from the start of counting the learning timer has elapsed, TCL 58 whether the steering angle neutral position learned flag F _H is set, that is present learning control is first at C8 Or not.

When the steering angle neutral position learned flag F _H is determined not to be set at this C8 steps, the neutral position of the new steering shaft 69 present steering shaft turning position [delta] _{m (n) is} at C9 δ
Read into the memory of the TCL58 is regarded as _{M (n),} it sets the steering angle neutral position learned flag F _H.

In this way, after setting the neutral position [delta] _M of the new steering shaft 69 _(n), while calculating the turning angle [delta] _H of the steering shaft 69 to the neutral position [delta] _{M (n)} of the steering shaft 69 as a reference , C10, the count of the learning timer is cleared, and the steering angle neutral position learning is performed again.

Steering angle neutral position learned flag F _H is determined in step C8 is set, that is, if the steering angle neutral position learning is determined to be the second or later, TCL 58 current steering shaft turning position at C11 δm _(n) is the neutral position δM _{(n-1) of the} previous steering shaft 69
Is determined, that is, δ _{m (n)} = δ _{M (n-1)} . Then, if it is determined that the current steering shaft turning position δ _{m (n)} is _equal to the previous steering shaft 69 neutral position δ _{M (n-1)} ,
Then, the process returns to step C10 and the next steering angle neutral position learning is performed again.

If it is determined in step C11 that the current steering shaft turning position δ _{m (n)} is not equal to the previous steering shaft 69 neutral position δ _{M (n-1)} due to play in the steering system, The current steering shaft turning position δ _{m (n)} remains unchanged and the new steering shaft 69 neutral position δ
_If the absolute value of these differences is greater than the preset correction limit amount Δδ without judging _{M (n)} , the previous steering axis
A value obtained by subtracting or adding the correction limit amount Δδ to the neutral position δM _{(n−1) of the} 82
_{M (n)} is read into the memory in TCL58.

That is, TCL58 is the current steering axis turning position δm _(n) at C12.
It is determined whether or not a value obtained by subtracting the previous neutral position ΔM _(n−1) of the steering shaft 69 from is smaller than a preset negative correction limit amount −Δδ. When it is determined that the value subtracted in the step of C12 is smaller than the negative correction limit amount -Δδ, the neutral position δM _(n) of the new steering shaft 69 is determined in C13 by the previous steering. Neutral position δ _{M (n-1) of} axis 69 and negative correction limit −Δ
δ is changed to δ _{M (n)} = δ _{M (n-1) −} Δδ, so that the learning correction amount per time does not unconditionally increase to the negative side.

Thus, even an abnormal detection signal from the steering angle sensor 70 for some reason has been output, is rapidly neutral position [delta] _M of the steering shaft 69 is not changed, it is possible to cope with the abnormality quickly.

On the other hand, when it is determined that the value subtracted in the step C12 is larger than the negative correction limit amount -Δδ, the neutralization of the previous steering shaft 69 from the current steering shaft turning position δm _(n) is performed in C14. It is determined whether the value obtained by subtracting the position ΔM _(n−1) is larger than the positive correction limit Δδ. When it is determined that the value subtracted in the step of C14 is larger than the positive correction limit amount Δδ, the neutral position δ of the new steering shaft 69 is determined in C15.
_{M (n)} is changed from the previous neutral position δM _(n-1) of the steering shaft 69 and the positive correction limit amount Δδ to δM _(n) = δM _(n-1) + Δδ, The learning correction amount is not unconditionally increased to the positive side.

Thus, even an abnormal detection signal from the steering angle sensor 70 for some reason has been output, is rapidly neutral position [delta] _M of the steering shaft 69 is not changed, it is possible to cope with the abnormality quickly.

However, when it is determined that the value subtracted in step C14 is smaller than the positive correction limit amount Δδ, the current steering shaft turning position δ _{m (n) is set} to the neutral position of the new steering shaft 69 in C16. δ
Read as it is as _{M (n)} .

Therefore, when the stopped vehicle 68 starts with the front wheels 60, 61 left in the turning state, the neutral position δ of the steering shaft 69 at this time
_As shown in FIG. 6 showing an example of the change state of _M , the steering shaft 69
When the learning control of the neutral position δ _M is the first time, the correction amount from the initial value δ _{m (0)} of the steering axis turning position in the step of M1 described above is very large, but the steering axis after the second time
69 the neutral position [delta] _M of the operation in step C13, C14, a suppressed and state.

In this way, after the learning correction of the neutral position [delta] _M of the steering shaft 69, the peripheral velocity V _FL of the vehicle speed V and the front wheel 60 and 61, the slip control for regulating the driving torque of the engine 11 based on the difference between V _FR Calculate the target drive torque T _OS when performing this.

By the way, in order to make the driving torque generated in the engine 11 work effectively, as shown in FIG. 7 showing the relationship between the friction coefficient between the tire and the road surface and the slip ratio of this tire, the front wheels 60, 60 The slip amount S of the front wheels 60, 61 is adjusted so that the slip ratio S of the tire 61 is at or near the target slip ratio S _O corresponding to the maximum value of the friction coefficient between the tire and the road surface. It is desirable not to impair the acceleration performance of.

Here, the slip ratio S of the tire is , And the like the slip ratio S becomes the target slip rate S _O or near corresponding to the maximum value of the friction coefficient between the tire and the road surface, but sets a target driving torque T _OS of the engine 11, the calculation procedure Is as follows.

First, the TCL58 calculates the longitudinal acceleration G _X of the current vehicle 68 from the vehicle speed V _(n) calculated this time using the above expression (1) and the vehicle speed V _(n-1) calculated one time before using the following expression (2) Calculate by

However, Δt is 15 ms, which is the sampling period of the main timer, and g is the gravitational acceleration.

Then, the driving torque TB of the engine 11 at this time is _calculated by the following equation (2).
It is calculated by:

T _B = G _XF · W _b · r + T _r (2) Here, G _XF is a corrected longitudinal acceleration that has passed through a low-pass filter that delays the change in the longitudinal acceleration G _X described above. The low-pass filter, the coefficient of friction and because it can be regarded as equivalent, the slip ratio S tires and the road surface of the tire longitudinal acceleration G _X is changed in the vehicle 68 of the longitudinal acceleration G _X is a tire of the vehicle and the road surface 68 Even if the target slip rate S _O corresponding to the maximum value of the coefficient of friction with the tire is likely to deviate from the vicinity thereof, the slip rate S of the tire is changed to the target slip rate S corresponding to the maximum value of the coefficient of friction between the tire and the road surface. _O or, as is maintained in the vicinity thereof, has a function of correcting the longitudinal acceleration G _X. Further, W _b is the weight of the vehicle body, r is the effective radius of the front wheels 60 and 61, and _Tr is running resistance. This running resistance _Tr can be calculated as a function of the vehicle speed V. It is calculated from the map shown in the figure.

On the other hand, during the acceleration of the vehicle 68, the wheel slip amount is usually about 3% with respect to the road surface.
When traveling on a rough road such as a gravel road, the maximum value of the coefficient of friction between the tire and the road surface corresponding to the target slip ratio S _O is generally larger than when traveling on a low μ road. Therefore, considering the slip amount and the road surface condition, the front wheels 6
The target drive wheel speed V _FO , which is the peripheral speed of 0.61, is calculated by the following equation (3).

Stage as the _{V FO = 1.03 · V + V} K ··· (3) where, V _K a road correction amount set in advance corresponding to the corrected longitudinal acceleration G _XF, the value of the correction longitudinal acceleration G _XF increases In this embodiment, the road surface correction amount _VK is obtained from a map such as that shown in FIG. 9 created based on a running test and the like.

Next, the slip amount S, which is the difference between the vehicle speed V and the target drive wheel speed V _FO , is calculated by the following equation (4) based on the equations (1) and (3).

Then, as shown in the following formula (5), the slip amount S is integrated while being multiplied by the integration coefficient K _I for each sampling period of the main timer, and the integrated correction torque for increasing the stability of control with respect to the target drive torque T _OS . T _I (however, T _I ≦ 0) is calculated.

Similarly, the proportional correction torque T _P for reducing the control delay with respect to the target drive torque T _OS proportional to the slip amount S is calculated by multiplying the proportional coefficient K _P as shown in the following equation (6). .

T _P = K _P · S (6) Then, the target drive torque T _OS of the engine 11 is calculated by the following equation (7) using the equations (2), (5), and (6).

Gear ratio of the transmission (not shown) [rho _m In the above equation, the [rho _d is a reduction ratio of the differential gear.

The vehicle 68 is provided with a manual switch (not shown) for the driver to select the slip control. When the driver operates the manual switch to select the slip control, an operation of the slip control described below is performed. I do.

As shown in FIG. 10 illustrating a flow of processing of the slip control, the detection and processing of various data described above in TCL58 first S1, but calculates the target driving torque T _OS,
This calculation operation is performed regardless of the operation of the manual switch.

Next, the slip control flag F _S at S2 is determines whether it is set initially slip control flag
Since F _S is not set, TCL58 uses front wheels 60 and 61 at S3.
It is determined whether or not the slip amount S is larger than a preset threshold value, for example, 2 km / hour.

If it is determined in step S3 that the slip amount S is greater than 2 km / h, the TCL 58 determines in step S4 whether the rate of change ΔG _S of the slip amount S is greater than 0.2 g.

If it is determined in step S4 that the slip amount change rate ΔG _S is greater than 0.2 g, the slip control flag is determined in step S5.
F _S is set, and it is determined again in S6 whether or not the slip control flag F _S is set.

At this step S6 when the slip control flag F _S is determined to be in the set, for slip control in advance calculated by the equation (7) as the target driving torque T _OS of the engine 11 at S7 Adopt the target drive torque T _OS .

Further, when the step in the slip control flag at F _S of the S6 is judged to have been reset, TCL 58 outputs at a maximum torque of the engine 11 as the target driving torque T _OS S8, thereby ECU54 is As a result of reducing the duty ratio of the torque control solenoid valves 46 and 51 to the 0% side, the engine 11 generates a drive torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

In this step of S8, the TCL 58 outputs the maximum torque of the engine 11 because the ECU 54 always sets the duty ratio of the torque control solenoid valves 46, 51 to 0% from the viewpoint of control safety and the like.
This is designed so that the engine 11 is operated in the direction of shutting off the power supply to the solenoid valves 46, 51 for controlling the torque, so that the engine 11 surely generates the driving torque according to the depression amount of the accelerator pedal 26 by the driver.

When it is determined in step S3 that the slip amount S of the front wheels 60, 61 is smaller than 2 km / h, or in step S4 it is determined that the slip amount change rate ΔG _S is smaller than 0.2 g, Continue to step S6,
L58 is the target drive torque T _{OS and} the maximum torque of the engine 11 is S8.
, The ECU 54 reduces the duty ratio of the torque control solenoid valves 46, 51 to the 0% side, and as a result, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 26 by the driver. To do.

On the other hand, in the step S2, the slip control flag F _S
If it is determined that is set, it is determined whether or not the idle switch 57 is turned on in S9, that is, whether or not the throttle valve 15 is fully closed.

If it is determined in step S9 that the idle switch 57 is on, the driver has not stepped on the accelerator pedal 26, so the slip control flag F _S is set in step S10.
Is reset, and the process proceeds to step S6.

Further, when the idle switch 57 is determined to be off at step S9, it is determined whether or not has been set again slip control flag F _S at step S6.

Incidentally, when the driver is not operating the manual switch to select slip control, TCL 58 After calculating the target driving torque T _OS for the to slip control as described above, the engine 11 in the case of performing turning control Calculate the target drive torque.

In controlling the turning of the vehicle 68, the TCL 58 calculates a target lateral acceleration G _YO of the vehicle 68 from the steering shaft turning angle δ _H and the vehicle speed V, and an acceleration in the vehicle longitudinal direction such that the vehicle 68 does not undergo extreme understeering. In other words, the target longitudinal acceleration G _XO
Is set based on the target lateral acceleration _GYO . And
The target drive torque of the engine 11 corresponding to this target longitudinal acceleration G _XO is calculated, and these target drive torques are output to the ECU 54.

By the way, the lateral acceleration G _Y of the vehicle 68 is the rear wheel speed difference | V _RL −V _RR
It is possible to actually calculate by using |, but by using the steering shaft turning angle δ _H , the value of the lateral acceleration G _Y acting on the vehicle 68 can be predicted, so that quick control can be performed. Have advantages.

However, simply obtaining the target drive torque of the engine 11 from the steering shaft turning angle δ _H and the vehicle speed V does not reflect the driver's will at all, and the driver may be dissatisfied with the maneuverability of the vehicle 68. There is. For this reason, the required drive torque _Td of the engine 11 desired by the driver is obtained from the depression amount of the accelerator pedal 26, and the engine drive is considered in consideration of the required drive torque _Td.
It is desirable to set 11 target drive torques. Also, 15
If the amount of increase or decrease of the target drive torque of the engine 11 set every millisecond is very large, a shock accompanying the acceleration and deceleration of the vehicle 68 occurs, leading to a decrease in ride comfort.
If the amount of increase / decrease in the target drive torque 11 is large enough to cause a decrease in the riding comfort of the vehicle 68, it is necessary to regulate the amount of increase / decrease in the target drive torque.

Furthermore, depending on whether the road surface is high μ road or low μ road,
If the target drive torque of 11 is not changed, for example, when driving the engine 11 with the target drive torque for a high μ road while driving on a low μ road, the front wheels 60 and 61 will slip, making safe driving impossible. Therefore, it is desirable that the TCL 58 calculates the target drive torque T _OH for the high μ road and the target drive torque T _OL for the low μ road, respectively.

As shown in FIG. 11 showing a calculation block of the turning control for a high μ road in consideration of the above knowledge, the TCL 58 calculates the vehicle speed V from the output of the pair of rear wheel rotation sensors 66 and 67 according to the above equation (1). And the steering angle δ of the front wheels 60 and 61 is calculated from the following equation (8) based on the detection signal from the steering angle sensor 70,
The target lateral acceleration G _YO of the vehicle 68 at this time is obtained from the following equation (9).

Here, ρ _H is the gear ratio of the steering gear, l is the wheel base of the vehicle 68, and A is the stability factor of the vehicle.

This stability factor A is, as is well known, the vehicle 68
The value is determined by the configuration of the suspension device and the characteristics of the tire. Specifically, the actual lateral acceleration G _Y generated on the vehicle 68 during a steady circular turn and the steering angle ratio δ _H of the steering shaft 69 at this time
/ Δ _HO (lateral acceleration G based on neutral position δ _M of steering shaft 69)
FIG. 12 shows the relationship between the turning angle δ _HO of the steering shaft 69 in the extremely low-speed running state where _Y is close to 0 and the turning angle δ _H of the steering shaft 69 during acceleration. It is expressed as the slope of the tangent in the graph. That is, lateral acceleration
In a region where G _Y is small and the vehicle speed V is not so high, the stability factor A is almost constant (A = 0.002), but when the lateral acceleration G _Y exceeds 0.6 g, the stability factor A sharply increases. However, the vehicle 68 will exhibit a very strong tendency to understeer.

Based on the above, based on Fig. 12,
Set stability factor A to 0.002 or less, and (9)
The driving torque of the engine 11 is controlled such that the target lateral acceleration G _YO of the vehicle 68 calculated by the formula is less than 0.6 g.

After calculating the target lateral acceleration G _YO in this way,
Advance the target lateral acceleration G _YO measurement and target longitudinal acceleration G _XO of vehicle speed V and the vehicle 68 which is set in response to a request from the map as shown in FIG. 13 previously stored in the TCL 58, the target longitudinal acceleration G _XO the following expression reference driving torque T _B of the engine 11 by (1
Calculated according to 0).

However, T _L is a road-load torque that is the resistance of the road surface obtained as a function of the lateral acceleration G _Y of the vehicle 68, and is obtained from the map as shown in FIG. 14 in this embodiment. Here, as shown in FIG. 14, as the load torque T _L , not only the rolling resistance component during turning but also
Includes cornering drag that changes with lateral acceleration. That is, when the lateral acceleration is zero as in straight running, only the rolling resistance component is present, but the cornering drag cannot be ignored during turning.

Next, in order to determine the adoption ratio of reference driving torque T _B,
To obtain a correction reference driving torque by multiplying the coefficient α of weighting the reference driving torque T _B. The weighting coefficient α is
It is set empirically by turning 68, but on high μ roads it is set to 0.
Use a value around 6.

On the other hand, shows the requested driving torque T _d to desired driver based on the accelerator opening theta _A detected by the engine speed N _E and an accelerator opening sensor 59 detected by the crank angle sensor 55 in FIG. 15 Then, the correction required drive torque corresponding to the weighting coefficient α is calculated by multiplying the required drive torque _Td by (1−α). For example, when setting the alpha = 0.6 is employed the ratio between desired driving torque T _d and the reference driving torque T _B is 6: 4.

Therefore, the target drive torque T _OH of the engine 11 is calculated by the following equation (11).

T _OH = α · T _B + (1−α) · T _d (11) The vehicle 68 is provided with a manual switch (not shown) for the driver to select the turning control for the high μ road. When the driver operates the manual switch to select the turning control for the high μ road, the driver performs the turning control for the high μ road described below.

As shown in FIG. 16 showing a flow of control for determining a target driving torque T _OH of the high μ road turning control, the detection and processing of various data described above in H1, the target driving torque T _OH This operation is performed independently of the operation of the manual switch.

Next, at H2, it is determined whether the vehicle 68 is in the turning control on the high μ road, that is, whether the high μ road turning control flag F _CH is set. At first, the high μ road turning control is not being performed, so it is determined that the high μ road turning control flag F _CH is in the reset state, and the target drive torque T _OH at H3 is a preset threshold value, for example (T _d −2 ) Determine whether or not
That is, the target drive torque T _OH can be calculated even when the vehicle 68 is traveling straight, but the value is usually much larger than the drive torque T _d required by the driver. However, since the required drive torque T _d is generally small when the vehicle 68 is turning, the time when the target drive torque T _OH becomes equal to or less than the threshold value (T _d −2) is determined as the start condition of the turning control. ing.

The threshold is set to (T _d -2) as a hysteresis for preventing control hunting.

At step H3, the target drive torque T _OH is set to the threshold (T _d −
2) If the following is determined, the TCL 58 determines at H4 whether the idle switch 57 is in the off state.

If it is determined in step H4 that the idle switch 57 is in the off state, that is, the accelerator pedal 26 is depressed by the driver, a high μ road turning control flag is set in H5.
F _CH is set. Next, whether the steering angle neutral position learned flag F _H is set at H6, i.e. a steering angle sensor
The authenticity of the steering angle δ detected by 70 is determined.

When the steering angle neutral position learned flag F _H is determined to be set at H6 step, whether high μ road turning control flag F _CH is set at H7 is determined again.

In the above procedure, the high μ road turning control flag F _CH is set at H5 step, high μ road turning control flag F _CH is determined to be set in step H7, The H8 The calculated value of the tip, that is, the target drive torque T _{OH in} the step of H1 is adopted as it is.

On the other hand, if it is determined in the step H6 that the steering angle neutral position learned flag F _H is not set, the steering angle δ calculated by the equation (8) is not reliable, so the equation (11) is used. The target drive torque T _OH calculated by the above is not adopted, and the TCL 58 outputs the maximum torque of the engine 11 as the target drive torque T _OH at H9, which causes the ECU 54 to determine the duty ratio of the torque control solenoid valves 46, 51. As a result of the reduction to the 0% side, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 26 by the driver.

If it is determined in the step H3 that the target drive torque T _OH is not equal to or less than the threshold value (T _d -2), the process proceeds from the step H6 or H7 to the step H9 without shifting to the turning control,
The TCL 58 outputs the maximum torque of the engine 11 as the target drive torque T _OH , whereby the ECU 54 reduces the duty ratio of the solenoid valves 46 and 51 for torque control to the 0% side. Generates a driving torque corresponding to the amount of depression of the vehicle.

Similarly, when the idle switch 56 is turned on in step H4, that is, when it is determined that the accelerator pedal 26 is not depressed by the driver, the TCL 58 outputs the maximum torque of the engine 11 as the target drive torque T _OH. , Which gives E
CU54 sets the duty ratio of torque control solenoid valves 46 and 51 to 0%
As a result of lowering to the side, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 26 by the driver and does not shift to the turning control.

If it is determined in step H2 that the high-μ road turning control flag F _CH is set, the target drive torque T _OC calculated this time and the target drive torque T _{OH (n- It} is determined whether the difference ΔT from ₁₎ is larger than a preset increase / decrease allowable amount T _K. This increase / decrease allowable amount T _K is a torque change amount that does not cause an occupant to feel an acceleration / deceleration shock of the vehicle 68. For example, the target longitudinal acceleration G _XO of the vehicle 68 is
If you want to reduce to 0.1g, use the formula (10) above. Becomes

The target drive torque T calculated this time in step H10
_If it is determined that the difference ΔT between _OC and the previously calculated target drive torque T _{OH (n-1)} is not greater than the preset increase / decrease allowable amount T _K , then in H11 the target drive torque T _OC and the previous time calculated target driving torque T _{OH (n-1)} and the difference ΔT is negative decrease tolerance T _K of
Is greater than.

If it is judged in step H11 that the difference ΔT between the target drive torque T _OC of this time and the target drive torque T _{OH (n-1)} calculated last time is larger than the negative increase / decrease allowable amount T _K , the target drive calculated this time Since the absolute value | ΔT | of the difference between the torque T _OC and the target drive torque T _{OH (n-1)} calculated last time is smaller than the increase / decrease allowable amount T _K ,
The calculated target drive torque T _OC of this time is directly used as the calculated value in the step of H8.

Also, the target drive torque T calculated this time in the step of H11
_If it is determined that the difference ΔT between _OC and the previously calculated target drive torque T _{OH (n-1)} is not larger than the negative increase / decrease allowable amount T _K , H12
At this time, the target drive torque T _OC of this time is corrected by the following formula, and this is adopted as the calculated value in the step of H8.

T _OC = T _{OH (n-1)} −T _K That is, the reduction range for the previously calculated target drive torque T _{OH (n-1)} is regulated by the allowable increase / decrease amount T _K , and deceleration is accompanied by the reduction of the drive torque of the engine 11. Reduce the shock.

On the other hand, if it is determined in step H10 that the difference ΔT between the target drive torque T _OC calculated this time and the target drive torque T _{OH (n-1)} calculated last time is equal to or greater than the increase / decrease allowable amount T _K , H13
At this time, the target drive torque T _OC of this time is corrected by the following formula, and this is adopted as the calculated value in the step of H8.

T _OC = T _{OH (n-1)} + T _{K In other} words, when the drive torque increases, the target drive torque T _OC calculated this time is the same as when the drive torque decreases.
And when the difference ΔT between the target driving torque T _{OH (n-1)} previously calculated exceeds the decrease tolerance T _K is increased or decreased tolerance to increase range to the target driving torque T _OH previously calculated _(n-1) and regulated by the T _K,
That is, the acceleration shock accompanying the increase in the driving torque of the engine 11 is reduced.

Thus, it represents the actual state of change and the longitudinal acceleration G _X and steering shaft turning angle [delta] _H and the target longitudinal acceleration G _XO and the target driving torque T _OH in the case of regulating the amount of increase or decrease the target driving torque T _OH by dashed lines as shown in FIG. 17, than the case shown by the solid line that did not restrict the decrease amount of the target driving torque T _OH, actual change in the longitudinal acceleration G _X becomes smooth and that the acceleration or deceleration shock is eliminated I understand.

When the target drive torque T _OH is set as described above, the TCL 58 determines at H14 whether or not the target drive torque T _OH is larger than the driver's required drive torque T _d .

Here, if the high-μ road turning control in-progress flag F _CH is set, the target drive torque T _OH is not larger than the driver's required drive torque T _d , so the idle switch 5
It is determined whether 7 is on.

If it is determined in step H15 that the idle switch 57 is not in the ON state, it is determined that the turning control is required, and the process proceeds to step H6.

Then, in step H6, it is determined that the steering angle neutral position learned flag F _H is set, and in step H7, it is determined that the high μ road turning control flag F _CH is set. For H1 or H12, the calculated value adopted in the step of H13 is selected as the target drive torque T _OH for turning control.

If it is determined in step H14 that the target drive torque T _OH is larger than the driver's required drive torque T _d , it means that the vehicle 68 has finished turning and the TCL 58
Resets the high-μ road turning control flag F _CH at H16.
Similarly, if it is determined in step H15 that the idle switch 57 is in the on state, the accelerator pedal 26 is not depressed, so the process proceeds to step H16 and the high μ road turning control flag F Reset _CH .

When the high μ road turning control flag F _CH is reset at H16, the TCL58 outputs the maximum torque of the engine 11 at H17 as the target drive torque T _OH , which causes the ECU 54 to control the torque control solenoid valve 46, As a result of reducing the duty ratio of 51 to the 0% side, the engine 11 generates a driving torque according to the depression amount of the accelerator pedal 26 by the driver.

After calculating the target drive torque T _OH for high μ road turning control, TCL58 sets the target drive torque T _OL for low μ road turning control.
Is calculated as follows.

By the way, on a low μ road, the target lateral acceleration G _YO is larger than the actual lateral acceleration G _Y, so the target lateral acceleration G _YO
Is greater than a preset threshold value, and if the target lateral acceleration G _YO is greater than this threshold value, it is determined that the vehicle 68 is on a low μ road, and turning control is performed if necessary. Good.

As shown in FIG. 18 showing the calculation block of the turning control for the low μ road, the target lateral acceleration G _YO is set as the above-mentioned expression (9) A from the steering shaft turning angle δ _H and the vehicle speed V, for example, 0.005 is adopted. To do.

Next, the target longitudinal acceleration G _XO is obtained from the target lateral acceleration G _YO and the vehicle speed V. In the present embodiment, the target longitudinal acceleration G _XO is read from the map shown in FIG.
This map shows the vehicle 6 according to the magnitude of the target lateral acceleration _GYO.
Target longitudinal acceleration G _XO that allows the vehicle to drive safely
And is set based on test driving results and the like.

Then, it calculates a reference driving torque T _B based on the target longitudinal acceleration G _XO by the equation (10), or to seek a map determining the adoption rate of the reference driving torque T _B. In this case, the weighting coefficient α is larger than the coefficient α for the high μ road, and is set as, for example, α = 0.8, but this reduces the reflection rate to the driver's request on the low μ road, and the risk is high. This is because the vehicle can be safely and reliably turned on a low μ road.

On the other hand, as the driver's required drive torque T _d , the one calculated during the calculation work for the high μ road is directly used, and therefore, the target drive torque T _d considering the required drive torque T _d to the reference drive torque T _B is used. T _OL is the following equation (1) similar to equation (11) above.
Calculated according to 2).

T _OL = α ・ T _B + (1-α) T _d (12) The vehicle 68 is provided with a manual switch (not shown) for the driver to select the turning control for the low μ road. When the driver operates the manual switch to select the turning control for the low μ road, the turning control for the low μ road described below is performed.

As shown in FIG. 20, which shows a control flow for determining the target drive torque _TOL for the low μ road turning control, the target drive torque is detected and calculated at L1 as described above. Although the torque _TOL is calculated, this operation is performed regardless of the operation of the manual switch.

Next, at L2, it is determined whether the vehicle 68 is in the turning control on the low μ road, that is, whether the low μ road turning control flag F _CL is set. Initially, the low μ road turning control is not being performed, so it is determined that the low μ road turning control flag F _CL is in the reset state, and the actual lateral acceleration G calculated by the rotation difference between the rear wheels 64 and 65 at L3. target lateral acceleration G _YO is whether greater than a predetermined threshold value by adding 0.05g in _Y, a large value is towards the target lateral acceleration G _YO than the actual lateral acceleration G _Y is i.e. a low μ road since, it is determined whether the target lateral acceleration G _YO is greater than the threshold value, when the target lateral acceleration G _YO is greater than the threshold value, judges the vehicle 68 is traveling on a low μ road. Note that the actual lateral acceleration generated in the vehicle 68
G _Y is the following formula (13) from the vehicle speed V of the peripheral speed difference between the rear wheels 64 and 65.
Is calculated as follows.

However, b is a tread.

At the step of L3, the target lateral acceleration G _YO is the threshold value (G _Y +0.05
g) larger, that is, when the vehicle 68 determines that the vehicle is turning on a low μ road, the TCL58 counts up a low μ road timer (not shown) built in the TCL58 at L4. The count time of the timer is, for example, 5 milliseconds.
And until the count of the low μ road timer is completed,
After shifting to the step after L6 described later, the target lateral acceleration G _YO according to the equation (9) and the actual lateral acceleration G _{Y according} to the equation (3) are calculated every 15 milliseconds to perform the determination operation in the step of L3. repeat.

In other words, until 0.5 seconds elapses from the count start of the low μ road timer, the process moves to the step of L8 through the steps of L6 and L7, and TCL58 outputs the maximum torque of the engine 11 as the target drive torque T _OL , As a result, the ECU 54 reduces the duty ratio of the torque control solenoid valves 46 and 51 to the 0% side,
The engine 11 generates a driving torque according to the amount of depression of the accelerator pedal 26 by the driver.

If the state where the target lateral acceleration G _YO is larger than the threshold value (G _Y +0.05 g) does not continue for 0.5 seconds, the TCL 58 determines that the vehicle 68 is not traveling on the low μ road, and at L9, sets the timer of the low μ road timer. The count is cleared and the process proceeds to steps L6 to L8.

If the target lateral acceleration G _YO is greater than the threshold value (G _Y + 0.05g) for 0.5 seconds, it is determined at L10 whether the idle switch 57 is in the off state, and the idle switch 57 is in the on state.
That is, when it is determined that the accelerator pedal 26 is not depressed by the driver, the count of the low μ road timer is cleared at L9 without shifting to the turning control of the low μ road, and L6 to
Upon shifting to the step of L8, the TCL58 outputs the maximum torque of the engine 11 as the target drive torque T _OL , which causes the ECU 54 to reduce the duty ratio of the torque control solenoid valves 46, 51 to the 0% side. Generates driving torque according to the amount of depression of the accelerator pedal 26 by the driver.

If it is determined in step L10 that the idle switch 57 is in the off state, that is, the accelerator pedal 26 is depressed by the driver, the low-μ road turning control flag _FCL is set in L11. Next, L6 by whether the steering angle neutral position learned flag F _H is set, that the authenticity of the steering angle δ detected by the steering angle sensor 70 is determined.

If it is determined that the steering angle neutral position learned flag F _H is set at L6 step, whether the low μ road turning control flag F _CL is set is determined again at L7.
Here, in the step of L11, the low μ road turning control flag F _CL
If is set, the previously calculated value in step L12, immediately, the target drive torque T _{OL in} step L1 is directly used.

When it is determined that the steering angle neutral position learned flag F _H is not set in the step of L6, there is no credibility of the steering angle δ, so the process proceeds to the step of L8 and was calculated in advance in L1 (13 ) without adopting a target driving torque T _OL of formula, TCL 58 outputs a maximum torque of the engine 11 as the target driving torque T _OL, thereby ECU54 is the duty ratio of the torque control solenoid valve 46 and 51 to 0% side As a result of the reduction, the engine 11 generates a driving torque according to the amount of depression of the accelerator pedal 26 by the driver.

On the other hand, the low μ road turning control flag
If the F _CL is determined to have been set, the process proceeds to L13 steps.

The steps in this L13～L16, as in the case of high μ road turning control, the difference ΔT increases or decreases capacity of the currently calculated target driving torque T _OL and the target driving torque T _OL previously calculated _(n-1)
It is determined whether or not it is larger than T _K , and in any case of increase or decrease, if this is within the increase / decrease allowable amount T _K , the target drive torque T _OL calculated this time is directly adopted as the calculated value in the step of L12, and ΔT If exceeds the increase / decrease allowable amount T _K , the target drive torque is regulated by the increase / decrease allowable amount T _K.

In other words, when decreasing the target drive torque T _OL , L
At 15, the current target drive torque T _OL is corrected to T _OL = T _{OL (n-1)} −T _K , and this is adopted as the value calculated in the step of L12. Conversely, in the case of increasing the target driving torque T _OL is calculated at this target driving torque T _OL is corrected to _{T OL = T OL (n-} 1) + T K, which L12 steps at L16 Adopt as a value.

When the target driving torque T _OL is set as described above, TCL 58 determines whether the target driving torque T _OL is greater than the required driving torque T _d of the driver at L17.

Here, if the low μ road turning control in progress flag F _CL is set, the target drive torque T _OL is not larger than the required drive torque T _d. the process proceeds to clear to L6, L7 step, wherein the steering angle neutral position learned flag F _H is determined to be set, further determines that the low-μ road turning control flag F _CL is set Then, the calculated value adopted in the step L1, L15, or L16 is selected as the drive torque _TOL for low-μ road turning control.

Further, even if it is determined in step L17 that the target drive torque T _OL is larger than the driver's required drive torque T _{d, the} steering shaft turning angle δ _H is not less than 20 degrees, for example, in the next L18. If the determination is made, the vehicle 68 is in the turning traveling, so the turning control is continued as it is.

When the target drive torque T _OL is determined to be larger than the driver's required drive torque T _{d in} the step of L17, and the steering shaft turning angle δ _H is determined to be less than 20 degrees in L18, for example, it means a state in which the turning of the vehicle 68 has been completed, TCL 58 resets the low μ road turning control flag F _CL at L19.

When the low-μ road turning control flag _FCL is reset in the step of L19, it is not necessary to count the low-μ road timer, so that the count of the low-μ road timer is cleared, and the L6, L7 the process moves to step, since the low μ road turning control flag F _CL is determined to be in the reset state at L7 step, the maximum TCL58 the engine 11 as the target driving torque T _OL shifts to L8 step As a result of outputting the torque, the ECU 54 reduces the duty ratio of the torque control solenoid valves 46 and 51 to the 0% side, and as a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

It is naturally possible to ignore the driver's required driving torque _Td in order to simplify the above-described turning control procedure. In this case, the target driving torque can be calculated by the above-described equation (10). it may be employed driving torque T _B.
Also, even when the driver's required driving torque _Td is taken into account as in the present embodiment, the weighting coefficient α is not set to a fixed value, but as time elapses after the start of control as shown in FIG. The value of the coefficient α may be gradually reduced, or may be gradually reduced according to the vehicle speed as shown in FIG. 22, so that the adoption rate of the driver's required driving torque _Td may be gradually increased.
With Similarly, some time after the control is started, as shown in FIG. 23 leave the value of the coefficient α to a constant value, or gradually decreased after a predetermined time period, or to an increase in the steering shaft turning amount [delta] _H It is also possible to increase the value of the coefficient α in such a manner that the vehicle 68 can travel safely, especially in a circuit in which the radius of curvature becomes gradually smaller.

In the arithmetic processing method described above, in order to prevent an acceleration / deceleration shock due to a sudden change in the driving torque of the engine 11,
Allowable increase / decrease when calculating the target drive torques T _OH and T _OL
The target driving torque T _OH by T _K, but the aim of regulating the T _OL, may be the regulation to be performed with respect to the target longitudinal acceleration G _XO. When an increase or decrease capacity of this case was G _K, n
The calculation process of the target longitudinal acceleration G _{XO (n)} at the time of rotation is described below.

If G _{XO (n)} -G _{XO (n-1)} > G _K , G _{XO (n)} = G _{XO (n-1)} + G _K G _{XO (n)} -G _{XO (n-1)} <-G _In the case of _K , G _{XO (n)} = G _{XO (n-1)} -G _{K If} the sampling time of the main timer is 15 milliseconds and the change in the target longitudinal acceleration G _XO is to be suppressed to 0.1 g per second, G _K = 0.1 · Δt.

After calculating the target drive torque T _OL for this low μ road turning control, TCL58 determines these three target drive torques T _OS ,
The optimum final target drive torque T _O is selected from T _OH and T _OL , and this is output to the ECU 54. In this case, in consideration of traveling safety, the target drive torque having the smallest numerical value is preferentially output to the vehicle 68. However, since the target drive torque T _OS for the slip control is generally always smaller than the target drive torque T _OL for the low μ road turning control, the slip control, the low μ road turning control, and the high μ road turning are generally used. What is necessary is just to select the final target drive torque T _O in the order of control.

As shown in FIG. 24 illustrating a flow of this process, the three target driving torque T _OS described above in M11, T _OH, after calculating the T _OL, is set slip control flag F _S at M12 Is determined.

If it is determined that the slip control flag F _S is set is determined in step M12, TCL 58 will target driving torque T _OS for slip control as a final target drive torque T _O
Is selected by M13, and this is output to the ECU 54.

The ECU 54, are mapped to determine the throttle opening theta _T is stored and a driving torque of the engine speed N _E and the engine 11 as parameters, M14 ECU 54 uses this map at the rotational speed current engine N _E and reads the target throttle opening theta _tO corresponding to the target driving torque T _OS. Then EC
U54 is a deviation between the actual throttle opening theta _T output from the target throttle opening theta _TO and the throttle opening sensor 56, meet the duty ratio of the pair of torque control solenoid valve 46 and 51 to the deviation By setting the value to a value, a current is supplied to the solenoids of the plungers 47 and 52 of the torque control solenoid valves 46 and 51, and the actual throttle opening θ _T is controlled to be reduced to the target value θ _TO by the operation of the actuator 36.

If it is determined in step M12 that the slip control flag F _S has not been set, it is determined in M15 whether the low μ road turning control flag F _CL has been set.

If it is determined in step M15 that the low μ road turning control in progress flag F _CL is set, the target driving torque T _OL for low μ road turning control is set to M16 as the final target driving torque T _O.
Select and move to step M14.

If it is determined in step M15 that the low μ road turning control flag _FCL is not set, it is determined in M17 whether the high μ road turning control flag _FCH is set.

If it is determined in step M17 that the high μ road turning control flag F _CH is set, the target driving torque T _OH for high μ road turning control is set to M18 as the final target driving torque T _O. To go to step M14.

On the other hand, if step at high μ road turning control flag F _CH of the M17 is determined not to be set, TCL 58 outputs a maximum torque of the engine 11 as a final target drive torque T _O, thereby ECU54 is As a result of reducing the duty ratio of the torque control solenoid valves 46 and 51 to the 0% side, the engine 11 generates a drive torque corresponding to the amount of depression of the accelerator pedal 26 by the driver. In this case, in this embodiment, the duty ratio of the pair of torque control solenoid valves 46, 51 is not unconditionally set to 0%, and the ECU 54 compares the actual accelerator opening θ _A with the maximum throttle opening restriction value. However, if the accelerator opening θ _A exceeds the maximum throttle opening regulation value, the duty ratio of the pair of torque control solenoid valves 46, 51 is adjusted so that the throttle opening θ _A becomes the maximum throttle opening regulation value. Decide and plunger 4
Drive 7,52. The maximum throttle opening regulation value as a function of engine speed N _E, a value (e.g., 2000 rpm) but at least is set to the fully closed state or the vicinity thereof, which in the following low rotation region, the engine rotation It is set to be gradually reduced to several tens of percent of the opening with the reduction in the number N _E.

The reason for restricting the throttle opening θ _T is as follows.
This is in order to increase the responsiveness of the control when the CL 58 determines that the drive torque of the engine 11 needs to be reduced. That is, the current design policy of the vehicle 68 is that the bore diameter (passage cross-sectional area) of the throttle body 16 tends to be extremely large in order to improve the acceleration performance and the maximum output of the vehicle 68.
There when in the low rotation region, the intake air amount in the order of several tens of percent throttle opening theta _T is saturated. Therefore, the throttle opening θ _{T is} determined according to the amount of depression of the accelerator pedal 26.
Rather than setting it to full open or its vicinity, the deviation between the target throttle opening θ _TO and the actual throttle opening θ _T when the drive torque reduction command is issued by restricting to a predetermined position. Is reduced, and the target throttle opening θ _TO can be quickly reduced.

In the above-described embodiment, two kinds of target drive torques for turning control of the high μ road and the low μ road are calculated, but the turning corresponding to the intermediate road surface between the high μ road and the low μ road is further performed. A target drive torque for control may be calculated, and a final target drive torque may be selected from these target drive torques.

Conversely, one type of target drive torque T _OM for turning control is calculated, and when slip control is in progress, this target drive torque T _OS for slip control is the target drive torque T _O for turning control.
_Since it is generally always smaller than _OM , it is naturally possible to select this target drive torque T _OS for slip control _prior to the target drive torque T _OM for turn control.

As shown in FIG. 25 illustrating a flow of processing of another embodiment according to the present invention, the above-mentioned target driving torque T _OM for turning control target driving torque T _OS for slip control at M21 after calculating in a manner similar to determines whether the slip control flag F _S is set at M22.

If during the slip control flag at this M22 in step F _S it is determined to be set, the final target driving torque
As T _O , select the target drive torque T _OS for slip control with M23. Then, in M24, the ECU 54 makes the current engine speed N _E
And the target throttle opening θ _TO corresponding to the target drive torque T _OS from the map stored in the ECU 54,
This target throttle opening θ _TO and the throttle opening sensor 56
The deviation from the actual throttle opening θ _T that is output from the torque control solenoid valve 4 is set by setting the duty ratio of the pair of torque control solenoid valves 46, 51 to a value commensurate with the deviation.
Current is applied to the solenoids of the plungers 47 and 52 of 6,51, and the actual throttle opening θ _T
Is controlled to fall to the target value θ _TO .

If it is determined in step M22 that the slip control flag F _S has not been set, it is determined in M25 whether the turning control flag F _M has been set.

If it is determined in step M25 that the turning control flag F _M is set, the target drive torque T _OM for turning control is selected in M26 as the final target drive torque T _O.
Move on to M24 step.

On the other hand, if it is determined in step M25 that the turning control flag F _M is not set, the TCL58 outputs the maximum torque of the engine 11 as the final target drive torque T _O , which causes the ECU 54 to control the torque. As a result of reducing the duty ratios of the solenoid valves 46, 51 to the 0% side, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 26 by the driver.

<Effect of the Invention> According to the vehicle turning control device of the present invention as specifically described above based on the embodiment, when setting the target drive torque, the load load torque is added and the load load torque is added to the load drive torque. Since the cornering drag that changes depending on the lateral acceleration is included, a more accurate target drive torque can be set. Therefore, as compared with the case where the cornering drag is not taken into consideration, the mistake of setting the target drive torque to an excessively small amount can be prevented in the range where the lateral acceleration is large, and the vehicle can turn more swiftly within a safe range.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an engine control system of one embodiment of a vehicle output control device according to the present invention, FIG.
FIG. 4 is a sectional view showing the drive mechanism of the throttle valve, FIG. 4 is a flow chart showing the overall flow of the control, FIG. 5 is a flow chart showing the flow of the neutral position learning correction control of the steering shaft, and FIG. FIG. 7 is a graph showing an example of the correction state of the learning value when the neutral position of the axis is learned and corrected, FIG. 7 is a graph showing the relationship between the friction coefficient between the tire and the road surface, and the slip ratio of this tire, and FIG. A map showing the relationship between the vehicle speed and the running resistance, FIG. 9 is a map showing the relationship between the corrected longitudinal acceleration and the speed correction amount, FIG. 10 is a flowchart showing the flow of slip control, and FIG. 11 is for a high μ road. FIG. 12 is a block diagram showing the procedure for calculating the target drive torque, FIG. 12 is a graph showing the relationship between the lateral acceleration and the steering angle ratio for explaining the stability factor, and FIG. 13 is the target lateral acceleration, vehicle speed, and target longitudinal acceleration. Represents the relationship with Map, FIG. 14 is a map showing the relationship between lateral acceleration and road load torque, FIG. 15 is a map showing the relationship between engine speed, accelerator opening and required drive torque, and FIG. 16 is for high μ roads. FIG. 17 is a flowchart showing the flow of the turning control, FIG. 17 is a graph showing the relationship between the steering shaft turning angle, the target drive torque and the longitudinal acceleration, and FIG. 18 is a block diagram showing the procedure for calculating the target drive torque for the low μ road. Fig. 19 is a map showing the relationship between target longitudinal acceleration, target lateral acceleration and vehicle speed, Fig. 20 is a flow chart showing the flow of turning control for low µ roads, and Figs. Graph showing the relationship between the time and the coefficient of weighting, FIG. 22 is a graph showing the relationship between the vehicle speed and the coefficient of weighting, FIG. 24 is a flowchart showing an example of the final target torque selection operation,
FIG. 25 is a flowchart showing another example of the final target torque selecting operation. In the figure, 11 is an engine, 12 is a combustion chamber, 13 is an intake pipe,
14 is an intake passage, 15 is a throttle valve, 17 is a throttle shaft,
18 is an accelerator lever, 19 is a throttle lever, 26 is an accelerator pedal, 27 is a cable, 29 is a claw, 30 is a stopper,
36 is an actuator, 38 is a control rod, 42 is a connection pipe, 43 is a vacuum tank, 44 is a check valve, 45 and 50 are pipes, 46 and 51
Is a solenoid valve for torque control, 54 is an ECU, 55 is a crank angle sensor, 56 is a throttle opening sensor, 57 is an idle switch, 58 is TCL, 59 is an accelerator opening sensor, 60 and 61 are front wheels,
62 and 63 are front wheel rotation sensors, 64 and 65 are rear wheels, 66 and 67 are rear wheel rotation sensors, 68 is a vehicle, 69 is a steering shaft, 70 is a steering angle sensor,
71 is a communication cable, A is a stability factor,
F _H is a steering neutral position learned flag, F _S is a slip control flag, F _CH is a high μ road turning control flag, F _CL is a low μ road turning control flag, F _M is a turning control flag, G _X is longitudinal acceleration, G _XO is target longitudinal acceleration, G _Y is lateral acceleration, G _YO is target lateral acceleration, g is gravitational acceleration, T _OS is target drive torque for slip control, and T _OH is target drive for high μ roads. Torque, T _OL are low μ
Target drive torque for road, T _OM is target drive torque for turning control, T _O is final target drive torque, T _B is reference drive torque, T _d
Is the required drive torque, V is the vehicle speed, S is the slip amount, θ _A is the accelerator opening, θ _T is the throttle opening, θ _TO is the target throttle opening, δ is the steering angle of the front wheels, and δ _H is the turning of the steering shaft. Horn,
δ _C is the steering shaft neutral position.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Masayuki Hashiguchi 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Masayoshi Ito 5-33-8 Shiba, Minato-ku, Tokyo (56) Reference JP-A-1-269624 (JP, A) JP-A-63-31863 (JP, A) JP-A-1-313633 (JP, A) JP-A 62- 10437 (JP, A) Actual Kaihei 1-270635 (JP, U))

Claims (1)

(57) [Claims] 1. A torque control means for reducing a drive torque of an engine independently of an operation by a driver, and a target acceleration in a longitudinal direction of a vehicle is set in accordance with a magnitude of a lateral acceleration during turning. A vehicle comprising a turning control unit that sets a target drive torque by adding load road torque to acceleration and controls the torque control means so that the drive torque of the engine becomes the target drive torque. A turning control device for a vehicle, wherein the torque includes a rolling resistance component and a cornering drag component that changes according to the lateral acceleration.