JPH03258939A - Device for controlling turning of vehicle - Google Patents

Abstract

PURPOSE:To restrict the lateral acceleration of a vehicle appropriately by com puting the lateral acceleration of a vehicle at the time of turning on the basis of detected values of a steering angle and the speed, and setting the target driving torque in response to the largeness thereof to operate a torque control means. CONSTITUTION:A torque computing unit 58 computes the lateral acceleration of a vehicle on the basis of the detecting signal of a steering angle sensor 70 and speed sensors (rotation sensors 62, 63, 66, 67 of front and rear wheels),and furthermore, sets the target driving torque of an engine 11 in response to the largeness of the lateral acceleration to output it to an ECU 54. The ECU 54 performs the duty control against a torque control solenoid valve 51 to throttle a throttle valve 15 or delay the ignition time or reduce a fuel supply quantity so that the driving torque of the engine 11 arrives the target driving torque, and the driving torque of the engine 11 is lowered to prevent an increase of the lateral acceleration of a vehicle. A vehicle can thereby travel on a turning road safe and securely.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is designed to quickly reduce the driving torque of an engine in accordance with the lateral acceleration that occurs when a vehicle turns, so that this turning operation can be easily and safely performed. The present invention relates to a turning control device for a vehicle.

<Prior art> Centrifugal force corresponding to the lateral acceleration in the direction perpendicular to the direction of travel is generated in a vehicle traveling on a turning path. Therefore, if the speed of the vehicle relative to the turning path is too high, the tire There is a risk that the vehicle body may skid by exceeding its grip strength.

In such cases, it is extremely difficult to reduce the engine output appropriately and drive the vehicle safely with a turning radius that corresponds to the turning path, especially when the exit of the turning path cannot be confirmed, or In cases where the radius of curvature of the turning path is gradually decreasing, extremely sophisticated driving techniques are required.

In general vehicles that have a so-called understeering tendency, it is necessary to gradually increase the amount of steering as the lateral acceleration applied to the vehicle increases, but when this lateral acceleration exceeds a value specific to each vehicle, the amount of steering increases. As mentioned earlier, this property has the property of rapidly increasing the number of times, making safe cornering difficult or impossible.

It is well known that this tendency is particularly noticeable in front-engine, front-wheel drive vehicles, which have a strong tendency to understeering.

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 how much the driver presses the accelerator pedal. An output control device has been proposed that allows the driver to safely drive through this turning path while suppressing the increase in vehicle speed, that is, the lateral acceleration of the vehicle, and maintaining the appropriate attitude of the vehicle. A vehicle has been announced that allows the user to select between driving using a control device and normal driving in which engine output is controlled in accordance with the amount of depression of the accelerator pedal.

Among methods related to vehicle output control based on such viewpoints, conventionally known methods include controlling the engine drive torque based on the amount of vehicle yawing (hereinafter referred to as yaw rate), etc. This is what I did.

In other words, the amount of yawing that mainly occurs during high-speed sharp turns of a vehicle tends to increase rapidly as the vehicle speed increases and the turns become sharper. Alternatively, if these exceed predetermined values, the driving torque of the engine is reduced.

Note that by using this output control device, it is also possible to suppress the slip of the drive member during acceleration of the vehicle, or to reduce shocks during gear changes in an automatic transmission.

<Problems to be Solved by the Invention> Conventional turning control devices that control engine drive torque based on the yaw rate, etc. of the vehicle while turning use a vibration sensor, acceleration sensor, etc. to detect the yaw rate, etc. of the vehicle. The driving torque of the engine cannot be controlled until after the yaw rate, etc. of the vehicle actually occurs.

Therefore, in a vehicle equipped with a conventional turning control device, it is basically impossible to avoid control delays, and it is impossible to safely and reliably run through this turning path while suppressing the lateral acceleration of the vehicle and maintaining an appropriate vehicle attitude. There was a risk that this would be impossible in some cases.

Means for Solving the Problems> The vehicle turning control device according to the present invention includes a torque control means that reduces the driving torque of the engine independently of the driver's operation, a steering angle sensor that detects the direction of the steered wheels, and a steering angle sensor that detects the direction of the steered wheels. , a vehicle speed sensor that detects the speed of the vehicle, and a lateral acceleration of the vehicle based on detection signals from the steering angle sensor and the vehicle speed sensor, and a target drive torque of the engine according to the magnitude of the lateral acceleration. The engine is equipped with a torque calculation unit for setting the torque, and an electronic control unit for controlling the operation of the torque control means so that the driving torque of the engine becomes the target driving torque set by the torque calculation unit.

Generally speaking, torque control means for reducing the engine's driving torque include delaying the ignition timing, reducing the amount of intake air or fuel supply, or stopping the fuel supply. As an example, it is also possible to adopt one in which the compression ratio of the engine is lowered.

Function> The torque calculation unit calculates the lateral acceleration of the vehicle based on the detection signal from the steering angle sensor and the detection signal from the vehicle speed sensor, and further calculates the target drive torque of the engine according to the magnitude of this lateral acceleration. settings and outputs this to the electronic control unit.

When the target driving torque of the engine is output from the torque calculation unit to the electronic control unit, the electronic control unit controls the operation of the torque control means so that the driving torque of the engine becomes the target driving torque. This reduces the vehicle's lateral acceleration and prevents it from increasing.

On the other hand, if the torque calculation unit determines that the vehicle is traveling straight based on the detection signal from the steering angle sensor, the electronic control unit does not operate the torque control means and the engine is operated based on the driver's operation. It will be done.

<Embodiment> As shown in FIG. 1 showing the concept of an embodiment in which the vehicle turning control device according to the present invention is applied to a front wheel drive type vehicle, and FIG. 2 showing the schematic structure of the vehicle, This intake pipe 1 is located in the middle of the intake pipe 13 connected to the combustion chamber 12.
3 by changing the opening degree of the intake passage 14 formed by
A throttle body 16 incorporating a throttle valve 5 for adjusting the amount of intake air supplied into the combustion chamber 12 is interposed.

As shown in FIG. 1 and FIG. 3, which shows an enlarged cross-sectional structure of the cylindrical throttle body 16, both ends of a throttle shaft 17 with a throttle valve 15 fixed thereto are rotatable. freely supported. An accelerator lever B and a throttle lever 19 are coaxially fitted into the -@ portion of the throttle shaft 17 that protrudes into the intake passage 14.

The cylindrical portion 20 of the throttle shaft 17 and the accelerator lever 18
A bushing 21 and a spacer 22 are interposed between the
This allows the accelerator lever 18 to rotate freely relative to the throttle shaft 17. Furthermore, the throttle shaft 17
With the washer 23 and nut 24 attached to one end side,
This prevents the accelerator lever 18 from being removed from the throttle shaft 17.

Also, a cable receiver 25 integrated with this accelerator lever 18
An accelerator pedal 26 operated by the driver is connected via a cable 27 to the accelerator pedal 2.
The accelerator lever 18 rotates with respect to the throttle shaft 17 according to the amount of depression of the throttle lever 6.

On the other hand, the throttle lever 19 is fixed integrally with the throttle shaft 17, and therefore the throttle lever 19 is fixed integrally with the throttle shaft 17.
By operating 9, the throttle valve 15 rotates together with the throttle shaft 17. Further, a collar 28 is coaxially fitted into the cylindrical portion 20 of the accelerator lever 18, and a claw portion 29 formed on a portion of the collar 28 is engaged with the tip portion of the throttle lever 19. A stopper 30 that can be stopped is formed. These claws 29 and stoppers 30
is set in a positional relationship such that when the throttle lever 19 is rotated in the direction in which the throttle valve 15 opens, or the accelerator lever 18 is rotated in the direction in which the throttle valve 15 is closed, they are mutually locked. ing.

A stopper 30 of the throttle lever 19 is pressed against the claw portion 29 of the accelerator lever 18 to close the throttle valve 15 between the throttle body 16 and the throttle lever 19.
A torsion coil spring 31 biasing in the opening direction is attached to a pair of nail-shaped spring receivers 32 fitted to the throttle shaft 17.
．． 33, and is mounted coaxially with this throttle shaft [7]. Also, between the stopper bin 34 protruding from the throttle body 16 and the accelerator lever 18,
Push the claw part 29 of the accelerator lever 18 into the throttle lever 19.
A torsion coil spring 35 is applied to the cylindrical portion 20 of the accelerator lever I8 via the collar 28 to bias the throttle valve 15 in the closing direction by pressing it against the stopper 30 of It is mounted coaxially with the throttle shaft 17.

At the tip of the throttle lever 19, there is a control rod 38 whose base end is fixed to the diaphragm 37 of the actuator 36.
The tips of the two are connected. The pressure chamber 39 formed within the actuator 36 includes the torsion coil spring 3.
1 and press the stopper 30 of the throttle lever 19 against the claw portion 29 of the accelerator lever 18 to close the throttle valve 15.
A compression coil spring 40 is incorporated to bias the opening direction. The spring force of the torsion coil spring 35 is set to be greater than the sum of the spring forces of these two springs 31 and 40, so that when the accelerator pedal 26 is depressed or the pressure in the pressure chamber 39 is The throttle valve 15 will not open unless the negative pressure is greater than the sum of the spring forces of the two springs 31 and 40.

A vacuum tank 43 communicates with a surge tank 41 connected to the downstream side of the throttle body 16 and forming a part of the intake passage 14 via a connecting pipe 42.
Between this vacuum tank 43 and the connecting pipe 42,
A check valve 44 that only allows air to move from the vacuum tank 43 to the surge tank 41 is interposed. As a result, the pressure within the vacuum tank 43 is set to a negative pressure approximately equal to the lowest pressure within the surge tank 41.

Inside these vacuum tanks 43 and the actuator 3
The pressure chamber 39 of No. 6 is in communication with the pressure chamber 39 through a pipe 45, and a first torque control solenoid valve 46 of a type that is closed when energized is provided in the middle of the pipe 45. In other words,
This torque control electromagnetic valve 46 has a built-in spring 49 that biases the plunger 47 against the valve seat 48 so as to close the pipe 45.

Further, a pipe 50 communicating with the intake passage 14 on the upstream side of the throttle valve 15 is connected to the pipe 45 between the first torque control solenoid valve 46 and the actuator 36 . A second torque control solenoid valve 51 of a dispersion type when not energized is provided in the middle of the pipe 50. That is, this torque control solenoid valve 51 includes a spring 53 that biases the plunger 52 to open the pipe 50.

The two torque control solenoid valves 46 and 51 include engine I
Electronic control unit 54 (hereinafter referred to as
These are called ECUs) are connected to each other, and this EC
Based on the command from U34, the on/off of energization to the torque control solenoid valves 46 and 51 is controlled by duty, and in this embodiment, these as a whole constitute the torque control means of the present invention. .

For example, when the duty rate of the torque control solenoid valve 46.51 is 0%, the pressure chamber 39 of the actuator 36 has an atmospheric pressure almost equal to the pressure in the intake passage 14 upstream of the throttle valve 15, and the throttle valve 15 The opening degree corresponds to the amount of depression of the accelerator pedal 26 on a one-to-one basis. Conversely, if the duty rate of the torque control solenoid valve 46.51 is 10
In the case of 0%, the pressure chamber 39 of the actuator 36 becomes a negative pressure almost equal to the pressure inside the vacuum tank 43, and the control rod 38 is pulled upward diagonally to the left in FIG.
The throttle valve 5 is closed regardless of the amount of depression of the accelerator pedal 26, and the driving torque of the machine riA11 is forcibly reduced. In this way, by adjusting the duty ratio of the torque control solenoid valves 46, 5], the opening degree of the throttle valve 15 is changed regardless of the amount of depression of the accelerator pedal 26, and the driving torque of the engine 11 can be adjusted arbitrarily. Can be adjusted.

The ECU 34 includes a crank angle sensor 55 attached to the engine 1 to detect the engine rotation speed, a throttle opening sensor 56 attached to the throttle body 6 to detect the opening of the throttle lever 19, and a throttle valve. An idle switch 57 that detects the fully closed state of the engine 15 is connected, and output signals from the crank angle sensor 55, throttle opening sensor 56, and idle switch 57 are sent, respectively.

The torque calculation unit (hereinafter referred to as TCL) 58 that calculates the target driving torque of the engine 11 includes the throttle opening sensor 56 and the idle switch 57.
An accelerator opening sensor 59 is attached to the throttle body 16 and detects the opening of the accelerator lever 18, and front wheel rotation sensors 62, 63 detect the rotational speed of a pair of left and right front wheels 60.6 which are driving wheels. , rear wheel rotation sensors 66 and 67 that detect the rotational speeds of a pair of left and right rear wheels 64 and 65, which are driven wheels, respectively, and detect the turning angle of the steering shaft 69 when turning based on the straight-ahead state of the vehicle 68. A steering angle sensor 70 is connected, and these sensors 5
Output signals from 9, 62°, 63, 66, 67, and 70 are sent, respectively.

The ECU 34 and the TCL 5 B are connected via a communication cable 71, and the ECU 34 sends information on the operating state of the engine 11, such as the amount of intake air, in addition to engine speed and detection signals from the idle switch 57 to the TCL 58. Sent. Conversely, the TCL 58 sends information regarding the target drive torque calculated by the TCL 58 to the ECU 34.

As shown in FIG. 4, which shows the general flow of control according to this embodiment, in this embodiment, the turning control is performed on a road surface with a relatively high coefficient of friction such as a dry road, and on a road surface with a relatively high coefficient of friction such as an icy road or a wet road. Control is performed separately for road surfaces with relatively low coefficients, and in addition to this turning control, slip control that controls the amount of slip of the front wheels 60 and 61 when the vehicle 68 accelerates is also performed at the same time. The target drive torque T of the engine 11 when this slip control is performed. S, and the target drive torque T of the engine 11 when turning control is performed on a road surface with a relatively high coefficient of friction such as a dry road (hereinafter referred to as a high μ road). H, and the target drive torque T of the engine 11 when turning control is performed on a road surface with a relatively low coefficient of friction (hereinafter referred to as a low μ road) such as a frozen road or a wet road. L and are always calculated in parallel by the TCL58, and these three target drive torques T os + T OHI
The optimum final target drive torque T0 is selected from TOf, so that the drive torque of the engine 11 can be reduced as necessary.

Specifically, the control program of this embodiment is started by turning on an ignition key (not shown), and the initial value δ of the steering shaft turning position is first set at Ml. , and performs initial settings such as resetting various flags and starting counting of the main timer every 15 milliseconds, which is the sampling period for this control.

Then, in M2, the TCL 58 calculates the vehicle speed ■, etc. based on the detection signals from various sensors, and then, in M3, learns and corrects the neutral position δ□ of the steering shaft 69. The six neutral positions of the steering shaft 69 of the vehicle 68 have an initial value δ every time the ignition key is turned on. , is read, but this initial value δ,. , are learned and corrected only when the vehicle 68 satisfies straight running conditions, which will be described later, and remain at this initial value δ until the ignition key is turned off. , is now corrected by learning.

Next, TCL57 is M4 with front wheel 60.61 and rear wheel 64
．． Target drive torque T when performing slip control that regulates the drive torque of the engine 11 based on the rotation difference with respect to 65. 5
The target drive torque T of the engine 11 when turning control is performed on a high μ road using M5. , and similarly M6
Target drive torque T of the engine 11 when turning control is performed on a low μ road. Compute L sequentially.

Then, in Ml, the TCL 57 determines the optimal final target drive torque T from these target drive torques T□s, T on + and TOL. is selected by a method described later, the ECU 34 selects a pair of torque control solenoid valves 46 so that the drive torque of the engine 11 becomes the final target drive torque T0.
．． 51, thereby controlling the duty rate of vehicle 68.
The vehicle is designed to run smoothly and safely.

In this way, the driving torque of the engine 11 is controlled at M8 until the countdown of the main timer ends, and when this pI falls, the countdown of the main timer is restarted at M9, and the steps from M2 to M9 are repeated as described above. Repeat until the ignition key is turned off.

The reason why the neutral position δ of the steering shaft 69 is learned and corrected in step M3 is when toe-in adjustment of the front wheels 60, 6 is performed during maintenance of the vehicle 68, or due to changes over time such as wear of the steering gear (not shown). , a deviation occurs between the turning amount of the steering shaft 69 and the actual steering angle δ of the front wheels 60 and 61, which are the steered wheels, and the steering shaft 69 is at a neutral position δ. This is because it may change.

The neutral position δ of this steering shaft 69. As shown in FIG. 5, which shows the procedure for learning and correcting the
Based on the detection signal from 6.67, the vehicle speed V is calculated at CI using the following formula (11).

■=VllL+VRR, (1) However, in the above equation, V RL + V RR are the circumferential speeds of the left and right rear wheels of 64.65, respectively.

Next, TCL58 has a pair of left and right rear wheels at C2 with 64.65
peripheral speed difference (hereinafter referred to as rear wheel speed difference) l
VRL, -VRRl are calculated.

Thereafter, the TCL 58 determines at C3 whether the vehicle speed V is greater than a preset threshold value VA. This operation
This is necessary because the rear wheel speed difference VIL VIRI due to steering cannot be detected unless the vehicle 68 reaches a certain high speed. It is set as appropriate, such as 20 km.

Then, when it is determined that the vehicle speed ■ is equal to or higher than the threshold value VA, the TCL 58 uses C4 to set the rear wheel speed difference IVILV engineer 1 to a threshold value ■, such as o, i km per hour, in advance.
, that is, whether the vehicle 68 is traveling straight. Here, the reason why the threshold value V is not set to Okm/hour is that if the tire pressures of the left and right rear wheels 64.65 are not equal, even though the vehicle 68 is traveling straight, the left and right rear wheels 64.65 Circumferential speed V RL, V
This is because the RRs will be different.

If it is determined in step C4 that the rear wheel speed difference IVIILv, R1 is less than the threshold value ■3, TCL58
5, the current steering shaft turning position δs (n+ is the previous steering shaft turning position δ detected by the steering angle sensor 64, ゎ−1,
Determine whether it is the same as. At this time, the steering angle sensor 70
It is desirable to set the turning detection resolution of the steering shaft 69 to around 5 degrees, for example.

In this step C5, the current steering shaft turning position δ,. ,
If it is determined that is the same as the previous steering shaft turning position δ, fi-1, the TCL5B determines at C6 that the current vehicle 68 is traveling straight, and A timer starts counting and continues for example for 0.5 seconds.

Next, at C7, the TCL 58 determines whether 0.5 seconds have elapsed since the learning timer started counting, that is, whether the vehicle 68 has been traveling straight for 0.5 seconds. in this case,
When the vehicle 68 first starts running, 0.5 seconds have not elapsed since the learning timer started counting, so when the vehicle 68 starts running, steps C1 to C7 are repeated.

When determining that 0.5 seconds have passed since the learning timer started counting, the TCL 58 sets the steering angle neutral position learned flag F at C8.

is set, that is, whether the current learning control is the first time.

At this step C8, the steering angle neutral position learned flag FM
If it is determined that is not set, the current steering shaft turning position δ, is determined at C9. , is regarded as the new neutral position δkNn+ of the steering shaft 69, and is read into the memory in the TCL 58, and the steering angle neutral position learned flag F8 is set.

In this way, the new neutral position δM(a
After setting l, the neutral position δML of this steering shaft 69,
While calculating the turning angle δ□ of the steering shaft 69 using , , as a reference, the count of the learning timer is cleared in the CIO,
The steering angle neutral position learning is performed again.

In step C8, the steering angle neutral position learned flag FM is set.
is set, that is, it is determined that the steering angle neutral position learning is being performed for the second time or later, TCL5g changes the current steering axis turning position δm+,n) to the previous steering axis 69 in C1l.
It is determined whether the current steering shaft turning position δ5o(a) is equal to the neutral position δM0-9 of the steering shaft 69, that is, δm++++”δ□3-1°.
If it is determined that it is equal to ++-11, the CIO
Returning to step , the next steering angle neutral position learning is performed again.

At step C1l, the current steering shaft turning position δ1. ,,
If it is determined that the position is not equal to the previous neutral position δM+++-11 of the steering shaft 69 due to play in the steering system, etc.
Current steering axis turning position δ,. , is not judged as the new neutral position δM+, . The value obtained by subtracting or adding this correction limit amount Δδ to the position δM0-1 is determined as the new neutral position δ1. of the steering shaft 69. IL, . . . is read into the memory within the TCL 58.

That is, TCL'58 is the current steering shaft turning position δ, 6. to the previous neutral position δM of the steering shaft 69 (*-
The value obtained by subtracting 11 is the preset negative correction limit amount - Δδ
Determine whether it is smaller than . If it is determined that the value subtracted in this step of CI2 is smaller than the negative correction limit amount -Δδ, a new steering axis 6 is set in CI3.
9, the neutral position δM (□) is changed from the previous neutral position δMfn-11 of the steering shaft 69 and the negative correction limit amount -Δδ to δ1.=δM+, -11-Δδ, and the learning correction per - Care is taken to ensure that the amount does not unconditionally increase to the negative side.

Thereby, even if an abnormal detection signal is output from the steering angle sensor 70 for some reason, the neutral position δ8 of the steering shaft 69 does not change suddenly, and this abnormality can be quickly dealt with.

On the other hand, if it is determined that the value subtracted in the step of CI2 is larger than the negative correction limit amount -Δδ, the current steering shaft turning position δmfs) is changed to the previous steering shaft 69 in C14.
It is determined whether the value obtained by subtracting the neutral position δM4 m-11 of is larger than the positive correction limit amount Δδ. Then, the value subtracted in this step C14 is a positive correction limit amount Δδ
If it is determined that the new neutral position δkNnl of the steering shaft 69 is larger than δM(wa)06Min-11+Δδ from the previous neutral position δMfn-11 of the steering shaft 69 and the positive correction limit amount Δδ in C15. , so that the learning correction amount per - time does not unconditionally increase to the positive side.

Thereby, even if an abnormal detection signal is output from the steering angle sensor 70 for some reason, the neutral position δ□ of the steering shaft 69 does not change suddenly, and this abnormality can be quickly dealt with.

However, if it is determined that the value subtracted in step C14 is smaller than the positive correction limit amount Δδ, then in C16 the current steering shaft turning position δ,1 is changed to the new neutral position δM( 1. Close and read out as is.

Therefore, when the stopped vehicle 68 starts with the front wheels 60 and 61 left in the turning state, as shown in FIG.
When the learning control of the neutral position δ□ of the steering shaft 69 is performed for the first time, the initial value δ of the steering shaft turning position in the above-mentioned step Ml
,. Although the amount of correction from , is very large, the Chinese position δ of the steering shaft 69 from the second time onwards. are C13, C15
The operation in step 2 brings about a suppressed state.

After learning and correcting the neutral position δ8 of the steering shaft 69 in this way, the vehicle speed V and the peripheral speed of the front wheels 60, 6] V FL I
Target drive torque T when performing slip control that regulates the drive torque of the engine 11 based on the difference from V FR. Calculate S.

By the way, in order to make the driving torque generated by the engine 11 work effectively, the front wheels 60. The front wheels 60.6 are set so that the slip rate S of the tire 61 is at or near the target slip rate S0 corresponding to the maximum value of the coefficient of friction between this tire and the road surface.
It is desirable to adjust the slip amount S of 1 so as not to impair the acceleration performance of the vehicle 68.

Here, the slip rate S of the tire is as follows, and the target drive torque T of the engine 11 is adjusted so that this slip rate S becomes at or near the target slip rate S0 corresponding to the maximum value of the coefficient of friction between the tire and the road surface. . The calculation procedure for setting S is as follows.

First, the TCL 58 calculates the current longitudinal acceleration Gx of the vehicle 68 using the following equation from the current vehicle speed v1 calculated using the above equation (1) and the vehicle speed V (11-11 calculated - times ago).

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

Then, the reference drive torque TB of the engine 11 at this time is calculated using the following formula (2).

Tn=Gxy-Wb-r+TR---(2) Here, G
xp is the corrected longitudinal acceleration that has been passed through a low-pass filter that delays the change in the longitudinal acceleration G mentioned above. Since the longitudinal acceleration Gx of the vehicle 68 can be considered to be equivalent to the coefficient of friction between the tires and the road surface, the low-pass filter changes the longitudinal acceleration G of the vehicle 68 and changes the tire slip rate S between the tires and the road surface. The target slip rate S corresponds to the maximum value of the friction coefficient. Or, even if the tire is about to deviate from that vicinity, the longitudinal acceleration Gx is corrected so as to maintain the tire slip rate S at or near the target slip rate S0 corresponding to the maximum value of the friction coefficient between the tire and the road surface. Has a function. Further, W is the vehicle weight, r is the effective radius of the front wheels 60°61, and T is the running resistance.This running resistance TR can be calculated as a function of the vehicle speed. It is obtained from the map shown in the figure below.

On the other hand, while the vehicle 68 is accelerating, it is normal for the wheels to always slip about 396 times against the road surface, and when driving on a rough road such as a gravel road, it is necessary to use a low μ road. The maximum value of the coefficient of friction between the tires and the road surface corresponding to the target slip ratio S0 is generally larger than when the vehicle is running.

Therefore, the target driving wheel speed (2) is the circumferential speed of the front wheels 60.61 which is targeted by taking into consideration such slip amount and road surface conditions. is calculated by the following formula (3).

■,. = 1.03・V+■...(3)
However, VK is a road surface correction amount set in advance corresponding to the corrected longitudinal acceleration GIF, and the corrected longitudinal acceleration G! has a tendency to increase stepwise as the value of , increases, but in this embodiment, this road surface correction amount 8 is determined from a map as shown in FIG. 9 created based on driving tests etc. There is.

Next, the slip amount S, which is the difference between the vehicle speed ■ and the target drive wheel speed V FO, is determined by the following formula (
Calculate according to 4).

5=Vyt+VFI y,. , , , (4) Then, as shown in equation (5) below, this slip amount S is integrated while multiplying the integral coefficient by 1 every sampling period of the main timer, and the target drive torque T is obtained. Integral correction torque T to improve control stability for S (however, T1≦0
) is calculated.

Similarly, the proportional correction torque T for alleviating the control delay with respect to the target drive torque Tos proportional to the slip amount S is calculated by multiplying the proportional coefficient by, as shown in equation (6) below.

T , = K P · S ... (6) Then, using the above formulas (2), (5), and (6), the machine II! is calculated by the following formula (7). III target drive torque T. S
Calculate.

T o s ” Kokoko [J Kokoro 1...(7) ρ諷0
ρd In the above equation, ρ1 is a gear ratio of a transmission (not shown), and ρ6 is a reduction ratio of a differential gear.

The vehicle 68 is provided with a manual switch (not shown) for the driver to select slip control, and when the driver selects slip control by operating this manual switch, the slip control operation described below is performed. I do.

As shown in FIG. 10, which shows the flow of this slip control process, the TCL 58 obtains the target drive torque T by detecting and calculating the various data described above at Sl. , but this calculation operation is performed independently of the operation of the manual switch.

Next, in S2, it is determined whether or not the slip control flag Fs is set, but since the slip control flag F is not set at first, the TCL 58 determines the slip amount of the front wheel 60.61 in S3. A threshold value preset by S,
For example, it is determined whether the speed is greater than 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 S4 whether the rate of change G of the slip amount S is greater than 0.2 g.

In this step S4, the slip amount change rate G8 is 0.2
If it is determined that the slip control flag F is larger than g, the slip control flag F is set in S5, and it is again determined in S6 whether the slip control flag F is set.

If it is determined in step 36 that the slip control flag F is being set, the target drive torque Tas for the engine 11 is set in step S7 to the slip control target calculated in advance using equation (7). The driving torque T as is adopted.

Also, in the step S6, the slip control flag F8 is set.
If it is determined that TC, L5 has been reset,
8 outputs the maximum torque of the machine [11] as the target drive torque T as at 88, and as a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to the 0% side. Accelerator pedal 26 by person
Generates driving torque according to the amount of depression.

Note that the reason why the TCL5B outputs the maximum torque of the engine 11 in this step S8 is due to the E
This is because the CU 34 is always operated in the direction of cutting off the current to the torque control solenoid valves 46 and 51 to ensure that the engine generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

In step S3, the slip amount S of the front wheels 60.61
is determined to be less than 2km/h, or S4
If it is determined in step S6 that the slip amount change rate G6 is smaller than 0.2g, the process directly proceeds to step S6, and TCL, 58, is the target drive torque T. As S, the maximum torque of the engine 11 is output in 88 steps,
This causes the ECU 34 to control the torque control solenoid valve 46.51.
As a result, the engine 1 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

On the other hand, in the step S2, the slip control flag F
If it is determined that , is set, it is determined in S9 whether the idle switch 57 is on, that is, the throttle valve 15 is fully closed.

If it is determined in step S9 that the idle switch 57 is on, the slip control flag F is set in the SIO because the driver has not depressed the accelerator pedal 26.

is reset, and the process moves to step S6.

If it is determined in step S9 that the idle switch 57 is off, the slip control flag F is set again in step S6.

Determine whether or not is set.

Note that if the driver does not operate the manual switch for selecting slip control, the TCL 58 sets the target drive torque T for slip control as described above. After calculating S, the target drive torque of the engine 11 when turning control is performed is calculated.

When controlling the turning of the vehicle 68, the TCL 58 determines the target lateral acceleration G of the vehicle 68 from the steering shaft turning angle δ and the vehicle speed V.
YO is calculated, and an acceleration in the longitudinal direction of the vehicle body that does not cause extreme understeering of the vehicle 68, that is, a target longitudinal acceleration G xo is set based on this hundred mark lateral acceleration Gyo. Then, the target drive torque of the engine 11 corresponding to this target longitudinal acceleration GXo is calculated.

By the way, the lateral acceleration GY of the vehicle 68 is the rear wheel speed difference I VR
It can actually be calculated using L VR-I, but by using the steering shaft turning angle δ□, the vehicle 6
Since it is possible to predict the value of the lateral acceleration Gy acting on the lateral acceleration Gy, it has the advantage that quick control can be performed.

However, depending on the steering shaft turning angle δ4 and the vehicle speed ■,
Merely determining the target drive torque of the engine 11 does not reflect the driver's intention at all, and there is a risk that the driver may remain dissatisfied with the maneuverability of the vehicle 68. Therefore, the required drive torque T of the engine 11 desired by the driver is controlled by the accelerator pedal 26.
It is desirable to set the target drive torque of the engine 11 in consideration of this required drive torque T6. Furthermore, if the increase or decrease in the target drive torque of the engine 11, which is set every 15 milliseconds, is extremely large, a shock will occur as the vehicle 68 accelerates and decelerates, resulting in a reduction in ride comfort. When the increase/decrease in the target drive torque 11 becomes large enough to cause a decrease in the ride comfort of the vehicle 68, it is also necessary to regulate the increase/decrease in the target drive torque.

Furthermore, depending on whether the road surface is a high μ road or a low μ road, engine 1
If the target drive torque of 1 is not changed, for example, if the engine 11 is operated with the target drive torque for a high μ road while driving on a low μ road, the front wheels 60° 61 will slip and safe driving will become impossible. Therefore, TCL58 is a target drive torque T for high μ roads. □ and target dynamic torque TOL for low μ road
It is desirable to calculate both.

As shown in FIG. 11, which shows a calculation block for turning control for high μ roads in consideration of the above knowledge, the TCL 5'8 calculates the vehicle speed V from the outputs of the pair of rear wheel rotation sensors 66 and 67 above (1). ) and based on the detection signal from the steering angle sensor 7o, the steering angle δ of the front wheels 60.61 is calculated using the following formula (
8) and calculate the target lateral acceleration GY of the vehicle 68 at this time.
0 is obtained from the following equation (9).

However, ρ□ is the steering gear transmission ratio, 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
This value is determined by the configuration of the suspension system, tire characteristics, etc. Specifically, the actual lateral acceleration GY generated in the vehicle 68 during a steady circular turn and the steering angle ratio δH/δ□ of the steering shaft 69 at this time. (Neutral position δ of steering shaft 69.

The turning angle δ□ of the steering shaft 69 in an extremely sluggish running state where the lateral acceleration GY is close to 0 with reference to . For example, the relationship between the turning angle δ□ of the steering shaft 69 during acceleration and the ratio of the turning angle δ□ of the steering shaft 69 during acceleration is expressed as the slope of a tangent in a graph as shown in FIG. 12, for example. In other words, the lateral acceleration Gy is small and the vehicle speed ■
In the region where Gy is not very high, the stability factor A is almost constant (A=0.002), but when the lateral acceleration Gy exceeds 0.6g, the stability factor A rapidly increases and the vehicle 68 It shows an extremely strong understeering tendency.

Based on the above, based on Figure 12,
Set stability factor A to 0.002 or less, and (
Target lateral acceleration GY0 of the vehicle 68 calculated by formula 9)
The driving torque of the engine 11 is controlled so that the torque is less than 0.6 g.

If the target lateral acceleration GYo is calculated in this way,
TC is the target longitudinal acceleration G
The reference drive torque TB of the engine 11 is calculated from the target longitudinal acceleration GXO using the following formula α0).

T, -Gworker + T, ...αO)ρak°
ρd However, TL is the road surface resistance obtained as a function of the lateral acceleration GY of the vehicle 68.
ad) Torque, which is obtained from a map as shown in FIG. 14 in this embodiment.

Next, in order to determine the adoption ratio of the reference drive torque TB,
This reference drive torque T is multiplied by a weighting coefficient α to obtain a corrected reference drive torque. The weighting coefficient α is set empirically by driving the vehicle 68 around a corner, and on a high μ road, a value of around 0.6 is adopted.

On the other hand, based on the engine speed N8 detected by the crank angle sensor 55 and the accelerator opening θ9 detected by the accelerator opening sensor 59, the required driving torque Td desired by the driver is determined from a map as shown in FIG. Then, the corrected required driving torque corresponding to the weighting coefficient α is calculated by multiplying the required driving torque T by (1-α). For example, when α is set to 0.6, the ratio of the reference drive torque TB to the required drive torque Td is 6:4.

Therefore, the target drive torque T of the engine 11. 8 is calculated using the following formula αυ.

T oH = (Z” T n + (1-α) - T.

(2) The vehicle 68 is provided with a manual switch (not shown) for the driver to select turning control for high μ roads, and the driver operates this manual switch to select turning control for high μ roads. When the turning control is selected, the following turning control operation for high μ roads is performed.

Target drive torque T for this high μ road turning control. .

As shown in FIG. 16, which shows the flow of control for determining the target drive torque TOH, the target drive torque TOH is calculated by detecting and calculating the various data described above in Hl. This is done regardless of the operation.

Next, at H2, it is determined whether the vehicle 68 is under high μ road turning control, that is, whether the high μ road turning control flag FC□ is set. At first, high μ road turning control is not in progress, so the high μ road turning control flag F is set. It is determined that H is in the reset state, and the target drive torque T is set at H3.

It is determined whether H is less than or equal to a preset threshold value, for example (Td2). In other words, the target drive torque T is maintained even when the vehicle 68 is traveling straight. H can be calculated, but its value is usually much larger than the driver's required drive torque T4. However, since this required drive torque T generally becomes smaller when the vehicle 68 turns, the target drive torque T. )
The time when I becomes equal to or less than the threshold value (T, -2) is determined as a condition for starting turning control.

Note that this threshold value is set to (Td-2) as a hysteresis to prevent control hunting.

Target drive torque T at step H3. H is the threshold (T,
-2) If it is determined that it is below, the TCL 58 determines in 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, then in step H5 the Solag F'c is turned on during high μ road turning control.

is set. Next, in H6, it is determined whether the steering angle neutral position learned flag FJI is set, that is, the reliability of the steering angle δ detected by the steering angle sensor 70.

When it is determined in step H6 that the steering angle neutral position learned flag F is set, it is again determined in Hl whether or not the high μ road turning control solag FCH is set.

In the above procedure, since the high-μ road turning control SOLAG FCH is set in step H5, the high-μ road turning control SOLAG F CH is set in the H1 step. It is determined that H is set, and the zero target drive torque T of the Ql) formula is calculated earlier in H8. H is adopted as the target drive torque TOH for high μ road turning control.

On the other hand, if it is determined that the steering angle neutral position learned flag FM is not set in step H6, the steering angle δ calculated by formula (8) is not reliable, so it is calculated by formula aD. target drive torque T. Does not adopt H, TCL58
is the target drive torque T. The maximum torque of the engine 11 is outputted as H9, and as a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to 0%, and as a result, the engine 11 outputs the maximum torque of the engine 11 as H9. Generates driving torque according to the

Further, the target drive torque T is set in step H3. +( is not below the threshold value (T, -2), the transition is made from step H6 or Hl to step H9 without transitioning to turning control, and the TCL 58 sets the maximum torque of the engine 11 as the target drive torque T.H. This outputs ECU34
As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

Similarly, even if it is determined in step H4 that the idle switch 56 is on, that is, 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 TQH. As a result, the ECU 34 activates the torque control solenoid valve 46.
．． As a result of lowering the duty rate of engine 51 to 0%, engine 11 generates a driving torque corresponding to the amount of depression of the accelerator and pedal 26 by the driver, and does not shift to turning control.

Sorag F during high μ road turning control in step H2. H
If it is determined that is set, the target drive torque T calculated this time by HIO. H. , and the previously calculated target drive torque TOH (.-1) is determined whether or not the difference ΔT is larger than a preset increase/decrease allowable amount TK. The amount of torque change is such that you do not feel the change, for example, in vehicle 6
8 target longitudinal acceleration G x.

If you want to suppress it to 0.1 g per second, use the above-mentioned equation 0) and calculate TK=0.1-TueniL・Δt ρ. ° ρd.

Target drive torque T calculated this time in the HIO step. Hl. , and the target drive torque T calculated last time. Hl.

-1, if it is determined that the difference ΔT is not larger than the preset increase/decrease allowable amount Tx, the current target drive torque T OH(n + and the previously calculated target drive torque T03..-1 It is determined whether the difference Δt is larger than the negative increase/decrease allowable amount TK.

The current target drive torque T at step Hll. H(n
l and the previously calculated target drive torque T o++ <fi
-+ r If it is determined that the difference ΔT is larger than the negative increase/decrease allowable amount TK, the target drive torque T calculated this time. ,.

, and the target drive torque T calculated last time. Since the absolute value 1ΔT of the difference from Hl, -1 is smaller than the allowable increase/decrease amount T8, the current target drive torque T is calculated. H3゜, remains the target drive torque T. Adopted as H.

Also, the target drive torque T calculated this time in step Hll. )I(nl and the previously calculated target drive torque T.

8. If it is determined that the difference ΔT from ゎ-, is not larger than the negative increase/decrease tolerance TK, the current target drive torque T is determined at Hl2. Set HI++1 using the following formula.

ToHfnl =TO11+11-+1 TK That is, the amount of decrease from the previously calculated target drive torque TOH+, -3 is regulated by the allowable increase/decrease amount TK, and the deceleration shock accompanying the reduction in the drive torque of the engine 11 is reduced.

On the other hand, the target drive torque T calculated this time in the HIO step. □. 1 and the target drive torque T calculated last time.

When it is determined that the difference Δt from HIn −11 is greater than the allowable increase/decrease amount TK, the current target drive torque T is determined at Hl3.

Hl. , is set by the following formula.

T O)+ +Ill =TOH(.-z 1TK In other words, in the case of an increase in the drive torque, as well as in the case of the decrease in the drive torque described above, the hundred mark drive torque T.Hfn
l and the previously calculated target drive torque T. H(n −1
If the difference ΔT from 1 exceeds the allowable increase/decrease amount TK, the previously calculated target drive torque T. )I-1, is regulated by the allowable increase/decrease amount T6, thereby reducing acceleration shock due to an increase in the driving torque of the engine 11.

In this way, the target drive torque T. Steering shaft turning angle δ□, target longitudinal acceleration CXO, and target drive torque T when the increase/decrease of H is regulated. As shown in FIG. 17, which shows the state of change between H and the actual longitudinal acceleration Gx, the target drive torque T
. Compared to the case where the increase or decrease of H is not regulated as shown by the broken line,
Actual longitudinal acceleration G! It can be seen that the change in is smooth, and the acceleration/deceleration shock has been eliminated.

The target drive torque T is obtained as described above. ) I is set, the TCL 58 sets this target drive torque T at Hl4. H
It is determined whether or not T is larger than the driver's requested driving torque T.

Here, if the high μ road turning control flag Fco is set, the target drive torque T. Since H is not larger than the driver's required drive torque Td, it is determined at H15 whether the idle switch 57 is in the on state.

If it is determined in step H15 that the idle switch 57 is not in the on state, this means that turning control is required, so the process moves to step H6.

Further, the target drive torque T is set at step HI4. If it is determined that H is larger than the driver's requested driving torque T, this means that the turning operation of the vehicle 68 has been completed, so the TCL 58 sets the high μ road turning control flag F at Hl6.
Reset cH. Similarly, when it is determined in step H15 that the idle switch 57 is in the on state,
Since the accelerator pedal 26 is not depressed, the process moves to step H16 and the high μ road turning control flag FC11 is reset.

At this Hl6, the high μ road turning control flag F is set. )1 is reset, the TCL58 becomes the target drive torque T. The maximum torque of the engine 11 is outputted as H9, and as a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to 0%, and as a result, the engine 11 outputs the maximum torque of the engine 11 as H9. Generates driving torque according to the

Target drive torque T for this high μ road turning control. After calculating H, TCL58 calculates target drive torque T for low μ road turning control. , is calculated as follows.

By the way, on a low μ road, the target lateral acceleration G yo has a larger value than the actual lateral acceleration GY, so it is determined whether the target lateral acceleration G yo is larger than a preset threshold value, and the target lateral acceleration G yo is determined. If G yo is larger than this threshold value, it is determined that the vehicle 68 is traveling on a low μ road, and turning control may be performed as necessary.

As shown in FIG. 18, which shows the calculation block of the turning control for low μ roads, the target lateral acceleration Gyo is calculated from the steering shaft turning angle δ9 and the vehicle speed V using the above equation (9), and the stability factor at this time is calculated from the steering shaft turning angle δ9 and the vehicle speed V. For example, 0.005 is adopted as A.

Next, the target longitudinal acceleration G□ is determined from the target lateral acceleration Gyo and the vehicle speed ■. However, in this embodiment, this target longitudinal acceleration G is calculated. is read out from a map as shown in FIG. This map expresses the target longitudinal acceleration CXO that allows the vehicle 68 to travel safely according to the magnitude of the target lateral acceleration G yo in relation to the vehicle speed ■, and is set based on test driving results etc. Ru.

Then, based on this target longitudinal acceleration Gxo, the reference drive torque TIl is calculated by the above-mentioned measurement or determined by a map to determine the adoption ratio of this reference drive torque T. In this case, the weighting coefficient α is the coefficient α for high μ roads.
For example, it is set as α-0,8,
This is because the ratio of reflection to the driver's request on low-μ roads is reduced, and the vehicle can safely and reliably turn around on highly dangerous low-μ roads.

On the other hand, as the driver's required drive torque T6, the one calculated during the calculation work for high μ roads is adopted as is, and therefore the target drive torque T is calculated by considering the required drive torque Td in addition to the reference drive torque T. , , is the following formula 0 which is similar to the above formula 0
Calculated by 2.

TOL=α・T　B+　(1−α)・T.

...0 The vehicle 68 is provided with a manual switch (not shown) for the driver to select turning control for low μ roads, and the driver operates this manual switch to control turning for low μ roads. When the control is selected, the turning control operation for low μ road described below is performed.

Target drive torque T for this low μ road turning control. As shown in FIG. 20, which shows the control flow for determining L, Ll
The target drive torque T is determined by detecting and calculating various data as described above. Although L is calculated, this operation is performed regardless of the operation of the manual switch.

Next, in L2, it is determined whether the vehicle 68 is under low μ road turning control, that is, whether the low μ road turning control flag FCL is set. At first, the low μ road turning control was not in progress), so it was determined that the low μ road turning control flag FCL was in the reset state, and the rear wheels were turned at 64°65 at L3.
0.0 to the actual lateral acceleration Gy calculated from the rotation difference of
By adding 5g, the target lateral acceleration G yo is larger than the preset threshold value). In other words, on a low μ road, the target lateral acceleration G yo becomes a larger value than the actual lateral acceleration GY. It is determined whether the target lateral acceleration GYO is larger than this threshold value, and if the target lateral acceleration GYO is larger than the threshold value, it is determined that the vehicle 68 is traveling on a low μ road. Incidentally, the actual lateral acceleration GY generated in the vehicle 68 is calculated from the difference in circumferential speed of the rear wheels 64°65 and the vehicle speed {circle around (2)} as shown in the following formula α3.

GY:■RL-VRR+■-0a also 3.62・b-g However, b is the 64.65 tread of the rear wheel.

Target lateral acceleration Gy in step L3.

is larger than the threshold (GY+0.05g), that is, the vehicle 68
If it is determined that the vehicle is turning on a low μ road, TCL58
At L4, a low μ road timer (not shown) built in the TCL 58 is counted up, and the count time of this low μ road timer is, for example, 5 milliseconds. Then, until the count of the low μ road timer is completed, the process moves to steps L6 and subsequent steps to be described later, and the target lateral acceleration G y is calculated every 15 milliseconds according to the equation (9).

and the actual lateral acceleration GY according to formula 03, and repeat the determination operation of L3.

That is, until 0.5 seconds have elapsed from the start of counting of the low μ road timer, the process moves to step L8 via steps Ll and L7, and TCL58 is the target drive torque T. The maximum torque of the engine 11 is output as L, which causes the ECU
34 reduces the duty ratio of the torque control solenoid valves 46 and 51 to 0%, 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.

If the target lateral acceleration Gyo is greater than the threshold value (Gy +0.05g) for 0.5 seconds, the TCL5B determines that the vehicle 68 is not traveling on a low μ road and sets the low μ road timer at L9. The count is cleared and the process moves to steps L6 to L8.

When the target lateral acceleration Gyo remains larger than the threshold value (Gy +0.05g) for 0.5 seconds, the LID determines whether the idle switch 57 is in the off state, and the idle switch 57 is in the on state, that is, the accelerator pedal is turned off. If it is determined that 26 is not depressed by the driver, the low μ road timer count is cleared at L9 without proceeding to turning control for low μ roads, and the process moves to steps L6 to L8. Then, TCL58 is the target drive torque T. Machine 1 as L! I
As a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to the 0% side, and as a result, the engine 11 outputs a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver. Occur.

If it is determined in step LIO that the idle switch 57 is off, that is, the accelerator pedal 26 is depressed by the driver, a low μ road turning control flag FCL is set in step Lll. Next, it is determined whether the steering angle neutral position learned flag F is set at Ll, that is, the reliability of the steering angle δ detected by the steering angle sensor 70 is determined.

If it is determined in step Ll that the steering angle neutral position learned flag F is set, it is determined again in step L7 whether or not the low μ road turning control flag FCL is set. Here, if the low μ road turning control flag FCL is set in step Lll, Ll2
The target drive torque T of the 03 formula previously calculated in step . L is the target drive torque T for low μ road turning control. Adopted as L.

In step L6, the steering angle neutral position learned flag F,
If it is determined that the steering angle δ is not set, the steering angle δ is unreliable, so the process moves to step L8, and the target drive torque T of the equation of α previously calculated at Ll. TCL without adopting L
5B is the target drive torque T. As a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to the 0% side, and as a result, the engine 11 responds to the amount of depression of the accelerator pedal 26 by the driver. Generates driving torque.

On the other hand, if it is determined in step L2 that the low μ road turning control flag FcL is set, Ll3
Move to the next step.

In steps L13 to L16, the target drive torque T calculated this time is used as in the case of high μ road turning control. L(
el and the previously calculated target drive torque T02. . -3
, it is determined whether the difference ΔT is larger than the allowable increase/decrease amount TK, and if this is within the allowable increase/decrease amount TK in either case, the currently calculated hundred mark driving torque T. L(1 is adopted as is, and if ΔT exceeds the allowable increase/decrease amount TK, the target drive torque is regulated by the allowable increase/decrease amount TK.

In other words, the target drive torque T. When decreasing L,
At Ll5, the current target drive torque TOL In l is TOL + II l = TOL. -11-TK
The target driving torque is T. When increasing L, the current target drive torque T is set at Ll6. LTnl T OL (n l ” T OL (.-z +Tx
Adopted as.

The target drive torque T is obtained as described above. When L is set, the TCL58 sets this target drive torque T at L17. It is determined whether L is larger than the driver's requested drive torque T6.

Here, if SORAG FC5 is set during low μ road turning control, the target drive torque T. L is the required driving torque T,
Since it is not larger than
Clear the road timer count and return to L6. The process moves to step L7, where it is determined that the steering angle neutral position learned flag FM has been set, and furthermore, that the low μ road turning control solag F cl is set, the target drive Torque T. L is the drive torque T for low μ road turning control. It is determined as L.

Further, the target drive torque T is set at step LI7. Even if it is determined that L is larger than the driver's requested driving torque Td, the steering shaft turning angle δ□ is set to 20, for example, at the next LlB.
If it is determined that the angle is not less than 1.degree., the vehicle 68 is currently turning, so the turning control continues.

If it is determined in step LI7 that the target drive torque TOL is larger than the driver's requested drive torque T, and if it is determined in L18 that the steering shaft turning angle δ8 is, for example, less than 20 degrees, the vehicle Since this means that the turning operation of 68 has been completed, the TCL 58 resets the Sorag FC4 during low μ road turning control at Li2.

At this LlB step, Solag Fc during low μ road turning control
When L is reset, there is no need to count the low μ road timer, so the count of this low μ road timer is cleared and the process moves to steps L6 and L7. During turning control, it is determined that the SORAG FCL is in the reset state, so the process moves to step L8 and the T
The CL58 outputs the maximum torque of the engine 11 as the target drive torque TOL, and as a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to the 0% side. Generates driving torque according to the amount of depression.

Note that it is naturally possible to ignore the driver's requested drive torque T6 in order to simplify the turning control procedure described above, and in this case, the reference drive that can be calculated by the above equation (10) is used as the target drive torque. It is sufficient to adopt the torque Tm. Furthermore, even when the driver's required drive torque T6 is taken into consideration as in this embodiment, the weighting coefficient α is not set to a fixed value, but is changed over time after the start of control as shown in FIG. By gradually decreasing the value of α, or by
As shown in the figure, the torque may be gradually decreased according to the vehicle speed, and the proportion of the driver's requested drive torque T6 may be gradually increased. Similarly, as shown in FIG. 23, the value of the coefficient α is kept constant for a while after the start of control, and after a predetermined time has elapsed, it is gradually decreased, or the amount of rotation of the steering shaft δ is
It is also possible to increase the value of the coefficient α as □ increases, so that the vehicle 68 can be driven safely, especially on a turning path where the radius of curvature gradually becomes smaller.

In addition, in the arithmetic processing method described above, in order to prevent acceleration/deceleration shock due to sudden fluctuations in the driving torque of the engine 11,
Target drive torque T. When calculating HITOL, this target drive torque To)IITOL is calculated using the increase/decrease allowable amount TK.
However, this regulation does not correspond to the target longitudinal acceleration G.
It may also be done for xo. When the allowable increase/decrease in this case is GK, the acceleration G before and after the hundredth mark at n times
The calculation process for XO is shown below.

G XO(n l G IO+, if -z>Gx,
G xo Tnl = Gxo fn-11+ GyG
XO(IIl, GKOflll -11<
For G K, G xotn,=Gxotn-x
Gx Note that when the sampling time of the main timer is 15 milliseconds and it is desired to suppress the change in the target longitudinal acceleration GXO to 0.1 g per second, G K = 0.1·Δt.

Target drive torque T for this low μ road turning control. After calculating L, TCL58 calculates these three target drive torques T.

Optimal final target drive torque T from Sr TOHI TOL. is selected and output to the ECU 34. In this case, the target drive torque with the smallest numerical value is output with priority given to the running safety of the vehicle 68. However, in general, the target drive torque T for slip control. S is the target drive torque T for low μ road turning control. Because it is always smaller than L, it is used for slip control.

The final target drive torque T0 may be selected in the order of low μ road turning control and high μ road turning control.

As shown in FIG. 24 showing the flow of this process, the three target driving torques T os + T o mentioned above in Mll are
After calculating n+TOL, it is determined in M12 whether or not the slip control flag F is set.

If it is determined that the slip control flag F is set in step M]2, the TCL 58 sets the target drive torque T for slip control as the final target drive torque T0. .

is selected by M13 and output to the ECU 34.

The ECU 34 stores a map for determining the throttle opening θa using the engine speed N2 and the driving torque of the engine 11 as parameters, and in M14, the ECU 34 uses this map to determine the current engine speed N2. This target drive torque T. The target throttle opening degree θ1° corresponding to S is read out. Next, the ECU 34 determines this hundreds of throttle opening degrees θa. and the actual throttle opening θa output from the throttle opening sensor 56, and set the duty ratio of the pair of torque control solenoid valves 46, 51 to a value commensurate with the deviation. A current is applied to the solenoid of the plunger 47.52 of the electromagnetic valve 46.51, and the actuator 36 is operated to control the actual throttle opening θa to fall to the target value θ1°.

If it is determined that the slip control flag F is not set in the step of MI2, M2S sets the low μ
It is determined whether the road turning control flag FCL is set.

At this M2S step, the low μ road turning control flag F
If it is determined that CL is set, the final target drive torque T. As target drive torque T for low μ road turning control. L is selected in M16, and the process moves to step M14.

Also, in the M2S step, the low μ road turning control flag F is set.
If it is determined that CL is not set, it is determined in M]7 whether the high μ road turning control flag FC)l is set.

Then, in step M17, the high μ road turning control flag F is set. If it is determined that 0 is set, the target drive torque T for high μ road turning control is set as the final target drive torque T0. H is selected in M2S and the process moves to step M14.

On the other hand, if it is determined in step M17 that the high μ road turning control flag F C) is not set,
TCL58 is the final target drive torque T. As a result, the ECU 34 lowers the duty rate of the torque control solenoid valve 46.51 to 0% side, and the engine 11 outputs the maximum torque of the engine 11.
Generates driving torque according to the amount of depression. In this case, in this embodiment, the duty rate of the pair of torque control solenoid valves 46 and 51 is not set to 0% unconditionally, and the ECU 34 compares the actual accelerator opening θ8 with the maximum throttle opening regulation value. , when the accelerator opening θ4 exceeds the maximum throttle opening regulation value, the pair of torque control solenoid valves 4 are set so that the throttle opening θ9 becomes the maximum throttle opening regulation value.
Determine the duty rate of 6.51 and make the plunger 47.5.
Drive 2. This maximum throttle opening regulation value is a function of the engine speed N2, and is set to a certain value (for example, 2000 rpm
m) Above, the opening is set at or near the fully closed state, but in the low rotation range below this, the opening is set to gradually decrease to several tens of percent as the engine speed NA decreases. It is.

The reason for regulating the throttle opening θa in this way is because T
This is to improve the responsiveness of the control when the CL5B determines that there is a need to reduce the driving torque of the engine 11. That is, the current design policy for the vehicle 68 is to improve the acceleration performance and maximum output of the vehicle 68 by adjusting the throttle body 1.
There is a tendency to make the bore diameter (passage cross-sectional area) of the engine 11 extremely large, and when the engine 11 is in a low rotation range, the intake air amount becomes saturated when the throttle opening θ1 is about several tens of percent.

Therefore, rather than setting the throttle opening θa to fully open or close to it depending on the amount of depression of the accelerator pedal 26, by regulating it to a predetermined position, when a command to reduce the driving torque is given. The giant throttle opening θa. This is because the deviation between the actual throttle opening θA and the actual throttle opening θA is reduced, and the throttle opening can be quickly lowered to the target throttle opening θT0.

In the above-described embodiment, the target drive torque for two types of turning control, high μ road and low μ road, is calculated. Target drive torques for control may be calculated, and the final target drive torque may be selected from these target drive torques.

Conversely, it is naturally possible to calculate the target drive torque T for one type of turning control.

<Effects of the Invention> According to the vehicle turning control device of the present invention, the magnitude of the lateral acceleration that occurs when the vehicle turns is calculated based on the detection signals from the steering angle sensor and the vehicle speed sensor, and the magnitude of the lateral acceleration is calculated based on the detection signals from the steering angle sensor and the vehicle speed sensor. Since the engine drive torque is reduced according to the vehicle's yaw rate, the magnitude of lateral acceleration can be estimated more quickly than the conventional method of detecting the magnitude of lateral acceleration based on the yaw rate etc. that actually occurs in the vehicle. can do. As a result, there is almost no control delay when turning, and it is possible to appropriately suppress the lateral acceleration of the vehicle and safely and reliably run through the turning path.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an embodiment of an engine control system that can realize the vehicle output control method according to the present invention, Fig. 2 is a conceptual diagram thereof, and Fig. 3 is a cross section showing the drive mechanism of the throttle valve. Figure 4 is a flowchart showing the overall flow of the control, Figure 5 is a flowchart showing the flow of the neutral position learning correction control of the steering shaft, and Figure 6 is a flowchart showing the flow of the neutral position learning and correction control of the steering shaft. A graph showing an example of the value correction state, FIG. 7 is a graph showing the relationship between the coefficient of friction between the tire and the road surface and the slip rate of this tire, and FIG. 8 is 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 a block diagram showing the procedure for calculating the target drive torque for high μ roads. , 12th
Figure 13 is a graph showing the relationship between lateral acceleration and steering angle ratio to explain the stability factor, Figure 13 is a map showing the relationship between target lateral acceleration, target longitudinal acceleration, and vehicle speed.
Figure 4 is a map showing the relationship between lateral acceleration and road load torque, Figure 15 is a map showing the relationship between engine speed, accelerator opening, and required drive torque, and Figure 16 is a map showing the relationship between engine speed, accelerator opening, and required drive torque. 17 is a graph showing the relationship between the steering shaft turning angle, target drive torque, and longitudinal acceleration. FIG. 18 is a block diagram showing the procedure for calculating the target drive torque for low μ roads. Figure 20 is a map showing the relationship between target longitudinal acceleration, lateral acceleration, and vehicle speed, Figure 20 is a flowchart showing the flow of turning control for low μ roads, Figure 21,
Fig. 23 is a graph showing the relationship between the time after the start of control and the weighting coefficient, Fig. 22 is a graph showing the relationship between the vehicle speed and the weighting coefficient, and Fig. 24 is an example of the final target torque selection operation. FIG. Also, in the figure, 11 is the engine, 12 is the combustion chamber, 13 is the intake pipe, 14 is the intake passage, 15 is the throttle valve, 17 is the throttle shaft, 18 is the accelerator lever, 19 is the throttle lever, 26 is the accelerator pedal, 27 is a cable, 29 is a claw portion, 30 is a stopper, 36 is an actuator, 38 is a control rod, 42 is a connecting pipe, 43 is a vacuum tank, 4
4 is a check valve, 45.50 is piping, 46.51 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 .61 is the front wheel, 64.65 is the rear wheel, 66°67 is the rear wheel rotation sensor, 68 is the vehicle, 69
is a steering shaft, 70 is a steering angle sensor, 71 is a communication cable, A is a stability factor, FcM is a high-μ road turning control flag, FCL is a low-μ road turning control flag, and G is a front and rear wheel. Acceleration, GXO is target longitudinal acceleration, Gy is lateral acceleration, Gyo is target lateral acceleration, g is gravitational acceleration,
ToH is the target drive torque for high μ roads, TOL is the target drive torque for low μ roads, To is the final target drive torque, T is the reference drive torque, T is the required drive torque, ■ is the vehicle speed, θ9 is the accelerator opening , θa is the throttle opening, θTO is the target throttle opening, δ is the steering angle of the front wheels, and δ□ is the turning angle of the steering shaft.

Claims (1)

[Claims] A torque control means that reduces the driving torque of the engine independently of the driver's operation, a steering angle sensor that detects the direction of the steered wheels, a vehicle speed sensor that detects the speed of the vehicle, and from these steering angle sensors and vehicle speed sensors. a torque calculation unit that calculates a lateral acceleration of the vehicle based on a detection signal of the vehicle and sets a target drive torque of the engine according to the magnitude of the lateral acceleration; A turning control device for a vehicle, comprising: an electronic control unit that controls the operation of the torque control means so as to achieve a set target drive torque.