JP2917409B2 - Vehicle turning control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention can quickly and safely reduce a driving torque of an engine in accordance with a lateral acceleration generated at the time of turning of a vehicle, and can perform this turning operation easily and safely. The present invention relates to a vehicle turning control device as described above.

<Conventional technology> A centrifugal force corresponding to a lateral acceleration in a direction perpendicular to the traveling direction is generated in a vehicle traveling on a circuit, and if the traveling speed of the vehicle with respect to the circuit is too high, a tire There is a possibility that the vehicle body may skid beyond the limit of the grip force of the vehicle.

In such a case, it is extremely difficult to run the vehicle safely with a turning radius corresponding to the turning circuit by appropriately reducing the output of the engine, especially when the exit of the turning circuit cannot be confirmed, or In the case where the radius of curvature of the circuit is gradually reduced, an extremely advanced driving technique is required.

In a general vehicle having a so-called understeering tendency, it is necessary to gradually increase the steering amount with an increase in the lateral acceleration applied to the vehicle. However, when the lateral acceleration exceeds a certain value specific to each vehicle, the steering becomes As described above, the fuel cell has such characteristics that it becomes difficult or impossible to make a safe turning operation as described above. In particular, it is well known that this tendency is remarkable in a front-engine front-wheel drive type vehicle that tends to understeer.

For this reason, the lateral acceleration of the vehicle is detected, and before the turning limit at which the vehicle becomes difficult or impossible to turn, the output of the engine is forcibly reduced regardless of the amount of depression of the accelerator pedal by the driver. An output control device that can safely run through the circuit while increasing the vehicle speed, that is, suppressing the lateral acceleration of the vehicle and appropriately maintaining the posture of the vehicle, is conceivable. There has been disclosed a device that allows selection between running using a control device and normal running in which the output of the engine is controlled in accordance with the amount of depression of an accelerator pedal.

Among those related to turning control of a vehicle based on such a viewpoint, a conventionally known one controls a driving torque of an engine based on, for example, a yawing amount (hereinafter, referred to as a yaw rate) of the vehicle. It was done.

In other words, yaw and the like that mainly occur during a high-speed sharp turn of the vehicle have a tendency that the amount thereof increases sharply as the vehicle speed is higher and the steeper turn, so that the yaw rate is detected by a vibration sensor, an acceleration sensor, or the like, Alternatively, when these values exceed a predetermined value, the driving torque of the engine is reduced.

By using this output control device, it is also possible to suppress the slip of the drive wheels during acceleration of the vehicle, or to reduce the shock and the like during shifting in the automatic transmission.

<Problems to be Solved by the Invention> In a conventional turning control device that controls the driving torque of the engine based on the yaw rate of the vehicle during turning, the yaw rate of the vehicle is detected by a vibration sensor, an acceleration sensor, or the like. The driving torque of the engine cannot be controlled until the yaw rate of the vehicle actually occurs.

Therefore, in a vehicle incorporating the conventional turning control device,
It was fundamentally impossible to avoid delay, and there was a possibility that it would be impossible in some cases to safely and reliably run through this circuit while suppressing the lateral acceleration of the vehicle and maintaining the vehicle's posture appropriately. .

<Means for Solving the Problems> A turning control device for a vehicle according to the present invention includes a torque control unit for reducing a driving torque of an engine independently of an operation by a driver, and a lateral acceleration detection for detecting a lateral acceleration of the vehicle. Means, an accelerator opening sensor for detecting an accelerator opening, reference driving torque setting means for setting a reference driving torque based on the lateral acceleration detected by the lateral acceleration detecting means, and an accelerator opening sensor detected by the accelerator opening sensor. Required driving torque calculating means for calculating a required driving torque of the driver based on the accelerator opening, and a reference driving torque set by the reference driving torque setting means and a required driving torque calculated by the required driving torque calculating means. Target drive torque setting means for setting a target drive torque by adding predetermined weights to each And when the lateral acceleration detected by the lateral acceleration detecting means is larger than a preset reference value, the torque is set so that the driving torque of the engine approaches the target driving torque set by the target driving torque setting means. And an electronic control unit for controlling the operation of the control means.

Incidentally, as a torque control means for reducing the driving torque of the engine, it is general to delay the ignition timing, reduce the intake air amount or the fuel supply amount, or stop the fuel supply. For example, an engine having a reduced compression ratio may be employed.

<Operation> The torque calculation unit calculates the lateral acceleration from the steering angle obtained by the steering angle sensor and the vehicle speed obtained by the vehicle speed sensor. When the lateral acceleration is larger than the reference value, the electronic control unit Is controlled so that the driving torque of the motor approaches the target driving torque. Here, as a method of calculating the target driving torque, a predetermined weighting for both driving torques is obtained from a reference driving torque calculated based on the lateral acceleration and a driver's required driving torque calculated based on the accelerator opening. Is added to the target drive torque, it is possible to perform control close to the driver's request.

Further, the present invention is a control only when the vehicle is in a state where the lateral acceleration is greater than the reference value and the possibility of occurrence of tire slip and unstable running is high, for example, only when turning. In other words, when the vehicle travels straight ahead where the lateral acceleration is smaller than the reference value, there is a low possibility that the running becomes unstable even if a slight tire slip occurs, so the control according to the present invention is not performed.

<Embodiment> As shown in Fig. 1 showing the concept of an embodiment in which the turning control device for a vehicle according to the present invention is applied to a front wheel drive type vehicle and Fig. 2 showing the schematic structure of the vehicle, the engine 11 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 to the inside 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 a 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
It rotates with it. 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, 40, whereby the accelerator pedal 26 is depressed or the pressure in the pressure chamber 39 is reduced. The throttle valve 15 is not opened unless the negative pressure is larger than the sum of the spring forces of the two springs 31 and 40.

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 lowest 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 solenoid valve 46 for torque control 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.

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 on / off of energization to the torque control solenoid valves 46 and 51 is duty-controlled based on a command from the ECU 54,
In the present embodiment, these components together constitute the torque control means of the present invention.

For example, when the duty ratio of the torque control solenoid valves 46 and 51 is 0%, the pressure chamber 39 of the actuator 36 has an atmospheric pressure substantially equal to the pressure in the intake passage 14 upstream of the throttle valve 15, and the throttle valve 15 The opening of the accelerator pedal 26
One-to-one correspondence with the amount of depression. 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 and 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.

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 has a function of the accelerator lever 18. An accelerator opening sensor 59 that detects the opening, front wheel rotation sensors 62 and 63 that detect the rotational speed of a pair of left and right front wheels 60 and 61 that are driving wheels, respectively, and a pair of left and right rear wheels 64 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 Conversely, from TCL58 this TCL58
Is transmitted to the ECU 54.

As shown in FIG. 4 showing a rough flow of the control according to the present embodiment, in the present embodiment, the turning control is performed on a road surface having a relatively high friction coefficient such as a dry road and a frictional surface such as a frozen road or a wet road. The control is performed separately on a road surface having a relatively low coefficient.In addition to the turning control, a slip control for controlling a slip amount of the front wheels 60 and 61 during acceleration of the vehicle 68 is also performed at the same time. , carried out a target drive torque T _OS of the engine 11 in the case of performing the slip control, a relatively high road surface friction coefficient as dry road or the like (hereinafter, the turning control in which a is referred to as high-μ road> Target turning torque T _OH of the engine 11 and a turning control 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). and a target driving torque T _OL of the engine 11 TCL 58
, Always calculate in parallel, these three target disturbance 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 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 learning 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 an optimal final target drive torque T _O from T _OH and T _OL by a method described later, the ECU 54 is provided with 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 travel safely without difficulty.

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 for learning correction of the neutral position [delta] _M of the steering shaft 69 at M3 step, due to aging such as wear or if not shown steering gear was toe adjustment of the front wheels 60 and 61 at the time of maintenance of the vehicle 68, the steering The turning amount of the shaft 69 and the front wheels 60, 6
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 ).

In the above equation, V _RL and V _RR are the peripheral velocities 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 high speed, the rear wheel speed difference due to steering |
V _RL −V _RR |
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輸速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 _{m (n-1)} detected by the steering angle sensor 64. Determine if there is. 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 step C5 that the current steering shaft turning position δm _(n) is the same as the previous steering shaft turning position δm _(n-1) , the TCL 58 becomes the current vehicle 68 in C6. Is determined to be in a straight-ahead state, the counting of a learning timer (not shown) built in the TCL 58 is started, and the counting is continued for, for example, 0.5 second.

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 It is determined whether 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, δm _(n) = δM _(n-1) . If it is determined that the current steering shaft turning position δm _(n) is _equal to the previous neutral position δM _(n-1) of the steering shaft 69, the process returns to step C10 and returns to the next steering angle neutral position again. Position learning is performed.

If it is determined in step C11 that the current steering shaft turning position δm _(n) is not equal to the previous neutral position δM _(n-1) of the steering shaft 69 due to play in the steering system or the like, The current steering shaft turning position δ _{m (n)} is used as it is as the neutral position δ of the new steering shaft 69.
_{If M (n)} is not determined and the absolute value of these differences differs by a preset correction limit amount Δδ or more, the previous steering shaft
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
From δ, it is changed to δM _(n) = δM _(n-1) -Δδ, so that the amount of learning correction per time is not unconditionally increased 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 and 61 kept in the turning state, the neutral position δ of the steering shaft 69 at this time is started.
_As shown in FIG. 6 showing an example of a change state of _M , the steering shaft 6
When learning control neutral position [delta] _M of 9 for the first time, although the correction amount very large from the initial value of the steering shaft pivoted position at step M1 of the aforementioned [delta] _{m (0),} the second and subsequent steering axis
Neutral position [delta] _M of 69, the operation in C13, C15 in step, the 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 by the engine 11 work effectively, as shown in FIG. 7 showing the relationship between the coefficient of friction between the tire and the road surface and the slip ratio of the tire, the front wheels 60, The slip amount s of the front wheels 60 and 61 is adjusted so that the slip rate S of the tire 61 is equal to or near the target slip rate S _O corresponding to the maximum value of the coefficient of friction between the tire and the road surface. It is desirable not to impair the acceleration performance of the vehicle.

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, calculated from TCL58 is the (1) and the vehicle speed V _(n-1) calculated before once the calculated current vehicle speed V _(n) by equation by the following equation longitudinal acceleration G _X current vehicle 68 I do.

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

Then, to calculate the reference driving torque T _B of the engine 11 at this time by the following equation (2).

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 body weight, r is the effective radius, T _R is running resistance of the front wheels 60 and 61, although the running resistance T _R can be calculated as a function of the vehicle speed V, the in this example 8 It is obtained from a map as 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 friction coefficient 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, the target driving wheel speed _VFO , which is the target peripheral speed of the front wheels 60 and 61, is calculated by the following equation (3) in consideration of the slip amount and the road surface condition.

_{V FO = 1.03 · V + V} K ... (3) where, V _K is road correction amount set in advance corresponding to the corrected longitudinal acceleration G _XF, stepwise as 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 or the like.

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

Then, as shown in the following equation (5), the slip amount s is integrated while being multiplied by the integration coefficient K _I at each sampling cycle of the main timer, and integration correction for improving the stability of control with respect to the target drive torque T _{OS is performed} . The torque T _I (where T _I ≦ 0) is calculated.

Similarly, the proportional correction torque T _P for mitigating control delay with respect to target driving torque T _OS proportional to the slip amount s the following equation (6) is calculated while being multiplied by a proportionality factor K _P .

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, TCL 58 by detection and calculation processing of various data described above in S1, but calculates the target driving torque T _OS, the arithmetic operation is the manual switch Is performed regardless of the operation of.

Next, the slip control flag F _S at S2 is determines whether it is set initially slip control flag
Since F _S has not been set, TCL58 has been
It is determined whether or not the slip amount s is larger than a preset threshold value, for example, 2 km / h.

Step by slip amount s of the S3 is determined to be larger than the hourly 2km, TCL 58 determines whether the rate of change G _s of the slip amount s is greater than 0.2g at S4.

When the slip rate of change G _s at this step S4 is determined to be greater than 0.2 g, the slip in S5 control Dear flag F _S
Sets determines whether the slip control flag F _S is set at S6 again.

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.

The reason that the TCL 58 outputs the maximum torque of the engine 11 in the step of S8 is that the ECU 54 is always operated in a direction to cut off the energization to the torque control solenoid valves 46 and 51 from the viewpoint of control safety and the like. This is because consideration has been given to ensure that a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver is generated.

When the case where the slip amount s of the front wheels 60 and 61 is determined in step S3 is determined to be smaller than the hourly 2km, the or S4 slip amount change rate G _s in step is determined to be smaller than 0.2g is Proceed directly to step S6 above, and TCL5
8 outputs at a maximum torque of S8 steps of the engine 11 as the target driving torque T _OS, thereby results ECU54 reduces the duty ratio of the torque control solenoid valve 46 and 51 to 0% side, the engine 11 is operating Driving torque corresponding to the amount of depression of the accelerator pedal 26 by the user.

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 depressed the accelerator pedal 26, and the slip control flag F _S is determined in 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.

At the time of turning control 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 longitudinal direction of the vehicle so 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 driving torque of the engine 11 corresponding to the target longitudinal acceleration G _XO is calculated.

By the way, the lateral acceleration GY of the vehicle 68 is _equal to the rear wheel speed difference | V _RL −V _RR
| It can be actually calculated by using, by utilizing the steering shaft turning angle [delta] _H, because it is possible to predict the value of the lateral acceleration G _Y acting on the vehicle 68, performing rapid control Can have the 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.

Further, depending on whether the road surface is a high μ road or a 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 dynamic 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 at the time of steady circular turning, the steering angle ratio of the steering shaft 69 when the [delta] _H
/ 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, the lateral acceleration
In an area 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
0).

However, T _L is the lateral acceleration G _Y Load Load (Road-Load) resistance at which the road surface is determined as a function of the torque of the vehicle 68, in this embodiment, are calculated from the map as shown in Figure 14.

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 the reference driving torque T _B and the required driving torque T _d 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 this manual switch to select the turning control for the high μ road, the turning control for the high μ road described below is performed.

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, it is determined at H2 whether the vehicle 68 is under the turning control on the high μ road, that is, whether the high μ road turning control flag _FCH is set. At first, since the high-μ road turning control is not underway, it is determined that the high-μ road turning control in-progress flag F _CH is in a reset state, and the target drive torque T _OH is set at H3 to a predetermined threshold value, for example (T _d −2 ) Determine whether or not:
In other words, 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 driver's required drive torque T _d . However, since the required drive torque _Td generally decreases when the vehicle 68 turns, the time when the target drive torque _TOH becomes equal to or less than the threshold value ( _Td- 2) is determined as the start condition of the turn control. ing.

The reason why the threshold value is set to (T _d -2) is 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 step at the steering angle neutral position learned flag F _H of the H6 is judged not to be set, since (8) is not credible of the steering angle δ calculated by the equation (11) below been without adopting a target driving torque T _OH calculation Te, TCL 58 is the maximum torque of the engine 11 as the target driving torque T _OH output at H9, this by ECU54 duty ratio of the torque control solenoid valve 46 and 51 As a result of the reduction to the 0% side, the engine 11 generates a driving torque according to the depression amount of the accelerator pedal 26 by the driver.

If it is determined in 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 step H6 or H7 to step H9 without shifting to 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, the engine 11 generates a drive torque corresponding to the amount of depression of the accelerator pedal 26 by the driver, and does not shift to 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 _OH calculated this time and the target drive torque T _{OH (n- It} is determined whether or not the difference ΔT from ₁₎ is larger than a preset increase / decrease allowable amount T _K. The increase / decrease allowable amount T _K is a torque change amount that does not cause the occupant to feel the acceleration / deceleration shock of the vehicle 68. For example, the target longitudinal acceleration G _XO of the vehicle 68 is changed every second.
If you want to keep 0.1g, use the above formula (10) Becomes

The target drive torque T calculated this time in step H10
_If it is determined that the difference ΔT between _OH and the previously calculated target drive torque T _{OH (n−1)} is not larger than the preset increase / decrease allowable amount T _K , the current target drive torque T _OH and the previous target drive torque T _OH are determined at H11. The difference ΔT from the calculated target drive torque T _{OH (n−1)} is a negative increase / decrease allowable amount T _K.
It is determined whether it is greater than or equal to.

When the difference ΔT between the present target driving torque T _OH and the target driving torque T _OH previously calculated _(n-1) in H11 in step is determined to be larger than the negative decrease tolerance T _K, the target drive currently calculated Since the absolute value | ΔT | of the difference between the torque T _OH and the previously calculated target drive torque T _{OH (n−1)} is smaller than the increase / decrease allowable amount T _K ,
The calculated current target drive torque T _OH is directly used as the value calculated in the step of H8.

Also, the target drive torque T calculated this time in the step of H11
When the difference ΔT between the _OH and the target driving torque T _OH previously calculated _(n-1) is not greater than the negative decrease tolerance T _K, H12
Then, the target drive torque T _OH of this time is corrected by the following equation, and this is adopted as the value calculated in the step of H8.

T _OH = T _{OH (n−1)} −T _{K In other} words, the reduction in the target drive torque T _{OH (n−1)} calculated last time is regulated by the allowable increase / decrease amount T _K , and the deceleration accompanying the reduction of the drive torque of the engine 11 is performed. It reduces shock.

On the other hand, when the difference ΔT between a currently calculated target driving torque T _OH and the target driving torque T _OH previously calculated _(n-1) in H10 in step is determined to be increased or decreased tolerance T _K or higher, H13
Then, the target drive torque T _OH of this time is corrected by the following equation, and this is adopted as the value calculated in the step of H8.

T _OH = T _{OH (n−1)} + T _{K In other} words, the target drive torque T _OH calculated this time is also used when the drive torque is increased, as in the case where the drive torque is reduced.
And if the difference △ T between the target driving torque T _{OH (n-1)} previously calculated exceeds the decrease tolerance T _K is increased or decreased based on gains for the target driving torque T _{OH (n-1)} previously calculated and regulated by the capacity 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. And
When the steering angle neutral position learning flag F _H at this H6 step is determined to be set, further the high μ road turning control flag F _CH is determined to be set in step H7, H
The calculated value adopted in step 1 or H12 or 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 TCL 58 outputs the maximum torque of the engine 11 at H9 as the target drive torque T _OH , whereby the ECU 54 causes the torque control solenoid valves 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 amount of depression of the accelerator pedal 26 by the driver.

In the present embodiment calculates the target driving torque T _OH of the engine 11 from the target lateral acceleration G _YO of vehicle 68, is compared with the target driving torque T _OH and preset threshold value (T _d -2), the target It is determined that the turning control is started when the driving torque T _OH becomes equal to or less than the threshold value (T _D -2). However, the target lateral acceleration G _YO of the vehicle 68 and a preset reference value, for example, 0.6 g, are directly determined. By comparison, when the target lateral acceleration _GYO becomes equal to or more than the reference value of 0.6 g, it is of course possible to determine to start the turning control.

After calculating the target driving torque T _OH for the high μ road turning control, the TCL 58 becomes the target driving torque T _OL for the 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 determined to be greater than or equal to a predetermined threshold. If the target lateral acceleration G _YO is greater than this threshold, the vehicle 68
It is determined that the vehicle is traveling on a low μ road, and turning control may be performed as necessary.

As shown in FIG. 18 showing a calculation block of the turning control for the low μ road, a target lateral acceleration G _YO is obtained from the steering shaft turning angle δ _H and the vehicle speed V by the aforementioned equation (9). For example, 0.005 is adopted as the ability factor A.

Next, a target longitudinal acceleration G _XO is obtained from the target lateral acceleration G _YO and the vehicle speed V. In this embodiment, the target longitudinal acceleration G _XO is read from a map as shown in FIG.
This map shows the vehicle 6 according to the magnitude of the target lateral acceleration _GYO.
The target longitudinal acceleration G _XO that allows the 8 to travel 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, for example, as α = 0.8. This is because the vehicle can turn safely and reliably on a high low μ road.

On the other hand, the requested driving torque T _d of the driver, the high μ road of those calculated when the calculation work is adopted as it is, therefore reference driving torque T target driving torque T in consideration of the required driving torque T _d to the _{B OL} is the following equation (12) similar to the above equation (11)
Is calculated by

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 this 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, it is determined in L2 whether the vehicle 68 is under the turning control on the low μ road, that is, whether the low μ road turning control in progress flag _FCL is set. At first, since the low μ road turning control is not being performed, it is determined that the low μ road turning control in progress flag F _CL is in a reset state, and the actual lateral acceleration G calculated based on the rotation difference between the rear wheels 64 and 65 in 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 Therefore, it is determined whether or not the target lateral acceleration G _YO is larger than this threshold, and the target lateral acceleration G _YO is determined.
_{If YO} is larger than the threshold value, it is determined that the vehicle 68 is traveling on a low μ road. Note that the actual lateral acceleration G _Y generated on the vehicle 68 is calculated by the following equation from the peripheral speed difference and the vehicle speed V of the rear wheel 64 and 65 (13).

Here, b is the tread of the rear wheels 64 and 65.

In the step L3, the target lateral acceleration G _YO is _equal to the threshold (G _Y +
When the TCL 58 determines that the vehicle 68 is turning on a low μ road, the TCL 58 counts up a low μ road timer (not shown) built in the TCL 58 at L4. The count time of the application timer is, for example, 5 milliseconds. Until the count for the low-μ road timer is completed, the process proceeds to steps after L6 described later, and the target lateral acceleration G _YO according to the above equation (9) and the actual lateral acceleration _GYO according to the above equation (13) are _executed every 15 milliseconds. The acceleration _GY is calculated and the operation of determining L3 is repeated.

That is, until 0.5 seconds from the count start of the low μ road timer has elapsed, the process proceeds to L8 step through step L6, L7, TCL 58 outputs a maximum torque of the engine 11 as the target driving 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, the timer for the low μ road. Is cleared and the process proceeds to steps L6 to L8.

If the state where the target lateral acceleration G _YO is larger than the threshold value (G _Y +0.05 g) continues for 0.5 seconds, it is determined at L10 whether or not the idle switch 57 is off, and the idle switch 57 is on,
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 for the low μ road, and L6
TCL58 proceeds to step ~L8 outputs the maximum torque of the engine 11 as the target driving torque T _OL, results thereby ECU54 reduces the duty ratio of the torque control solenoid valve 46 and 51 to 0% side, the engine 11 is the accelerator pedal 26 by the driver
Generates a driving torque corresponding to the amount of depression of the vehicle.

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, during low-μ road turning control in step L11, flag F
_{If CL} is set, the calculated value at the step of L12, that is, the target drive torque T _OL at the step of L1, is set.
Is adopted as it is.

When the steering angle neutral position learned flag F _H determined in step L6 is judged not to be set, since there is no credibility of the steering angle δ proceeds to L8 step was calculated previously by 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, the engine 11 generates a drive torque corresponding 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. If the increase or decrease is within the allowable change amount T _K , the target drive torque T _OL calculated this time is directly used as the value calculated in the step of L12, and ΔT There when exceeds the decrease tolerance T _K regulates the target drive torque at decreasing tolerance T _K.

That is, when reducing 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, the at L17 step even when the target driving torque T _OL is determined to be larger than the required driving torque T _d of the driver, the steering shaft turning angle [delta] _H in the next L18, for example, not less than 20 degrees If it is determined that the vehicle 68 is turning, the turning control is continued.

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 the low μ road turning control, the TCL 58 calculates these three target drive torques T _OS ,
An optimum final target drive torque T _O is selected from T _OH and T _OL and output to the ECU 54. In this case, in consideration of the running safety of the vehicle 68, the target drive torque having the smallest numerical value is output with priority. 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 in 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. Comparison In this case, not the 0% duty ratio of the pair of torque control solenoid valve 46 and 51 unconditionally in this embodiment, ECU 54 is the actual accelerator opening theta _A and the maximum throttle opening regulation value If the accelerator opening θ _A exceeds the maximum throttle opening restriction value, the duty ratio of the pair of torque control solenoid valves 46 and 51 is adjusted so that the throttle opening θ _A becomes the maximum throttle opening restriction value. Decision Branja 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 the number +% degree of opening in accordance 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 tends to make the bore diameter (cross-sectional area of the passage) of the throttle body 16 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 by the throttle opening theta _T about several +% 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, it is naturally possible to calculate one type of target drive torque for turning control.

<Effect of the Invention> According to the vehicle turning control device of the present invention, the magnitude of the lateral acceleration generated when the vehicle turns is calculated based on the detection signals from the steering angle sensor and the vehicle speed sensor, and the calculated lateral acceleration is calculated. When the acceleration is greater than a preset reference value, a predetermined driving torque calculated based on the lateral acceleration and a driver's required driving torque calculated based on the accelerator opening are determined based on a predetermined driving torque in both driving torques. Since the engine drive torque is controlled so as to approach the weighted target drive torque, the magnitude of the lateral acceleration is detected more quickly than the conventional method of detecting the magnitude of the lateral acceleration based on the yaw rate actually generated in the vehicle. And the accelerator opening indicating the driver's request can be reflected in the control. As a result, there is almost no control delay at the time of turning, and the lateral acceleration of the vehicle can be appropriately suppressed, and the vehicle can safely and reliably run through the circuit. In addition, the control based on the present invention is not performed because the possibility of running instability is low even when a slight tire slip occurs during straight traveling, and therefore, acceleration during straight traveling is ensured.

[Brief description of the 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 cross-sectional view showing the drive mechanism of the throttle valve, FIG. 4 is a flowchart showing the overall flow of the control, FIG. 5 is a flowchart showing the flow of neutral position learning correction control of the steering shaft, and FIG. FIG. 7 is a graph showing an example of a correction state of a learning value when the neutral position of the shaft is learned and corrected, FIG. 7 is a graph showing a relationship between a friction coefficient between a tire and a road surface, and a slip ratio of the tire, and FIG. A map showing the relationship between vehicle speed and 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 a procedure for calculating a target drive torque of FIG. 12, FIG. 12 is a graph showing a relationship between a lateral acceleration and a steering angle ratio for explaining a stability factor, and FIG. 13 is a diagram showing a target lateral acceleration, a target longitudinal acceleration and Express the relationship with vehicle speed 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 a map for high μ roads. Flow chart showing the flow of the turning control, FIG. 17 is a graph showing the relationship between the steering shaft turning angle, the target driving torque and the longitudinal acceleration, and FIG. 18 is a block diagram showing the procedure for calculating the target driving torque for a low μ road. FIG. 19 is a map showing a relationship between a target lateral acceleration, a target longitudinal acceleration, and a vehicle speed, FIG. 20 is a flowchart showing a flow of a turning control for a low μ road, and FIGS. FIG. 22 is a graph showing the relationship between the time and the weighting coefficient, FIG. 22 is a graph showing the relationship between the vehicle speed and the weighting coefficient, and FIG. 24 is a flowchart showing an example of the operation of selecting the final target torque. Reference numerals 11 in the figure denote an engine, 12 a combustion chamber, 13 an intake pipe, 14 an intake passage, 15 a throttle valve, 17 a throttle shaft, 18 an accelerator lever, 19 a throttle lever, and 26 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 piping, 4
6,51 is a torque control solenoid valve, 54 is an ECU, 56 is a throttle opening sensor, 57 is an idle switch, 58 is a TCL, 59 is an accelerator opening sensor, 60 and 61 are front wheels, 64 and 65 are rear wheels, 66,67
Is a rear wheel rotation sensor, 68 is a vehicle, 69 is a steering axis, 70 is a steering angle sensor, 71 is a communication cable, A is a stability factor, F _CH is a turning control flag for high μ road turning, and F _CL is low. μ road 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 _OH is high μ road target driving torque, T _OL is the target drive torque for low μ road, T _O is the final target drive torque, T _B is the reference drive torque, T _d is the required drive torque, V is the vehicle speed, θ _A is the accelerator opening, and 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 angle of the steering shaft.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadao Tanaka 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Masaki Tani 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Kiichi Yamada 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Hiroaki Yoshida 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Masayuki Hashiguchi 5-33-8, Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Masayoshi Ito 5-33-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Hiroshi Yoshida 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) References JP-A-61-253228 (JP, A) JP Hei 2-27124 ( P, A) JP Akira 62-23831 (JP, A) JP Akira 62-10437 (JP, A) (58 ) investigated the field (Int.Cl. ^6, DB name) F02D 29/00 - 29/06

Claims (1)

(57) [Claims] A torque control means for reducing a driving torque of an engine independently of an operation by a driver; a lateral acceleration detection means for detecting a lateral acceleration of a vehicle; an accelerator opening sensor for detecting an accelerator opening; Reference driving torque setting means for setting a reference driving torque based on the lateral acceleration detected by the lateral acceleration detecting means; and calculating a required driving torque of the driver based on the accelerator opening detected by the accelerator opening sensor. Required drive torque calculating means, and a predetermined weight is respectively applied to the reference drive torque set by the reference drive torque setting means and the required drive torque calculated by the required drive torque calculating means. A target driving torque setting means for setting a target driving torque; and a lateral acceleration detected by the lateral acceleration detecting means. An electronic control unit that controls the operation of the torque control means so that the drive torque of the engine approaches the target drive torque set by the target drive torque setting means when is larger than a preset reference value. A turning control device for a vehicle, comprising: