JPH03258935A - Method for controlling output of vehicle - Google Patents

Abstract

PURPOSE:To restrict the lateral acceleration by obtaining the target lateral acceleration with a stability factor, and obtaining the acceleration fore and aft of the target with the lateral acceleration and the speed, and furthermore, obtaining the standard driving torque to restrict the operation of a torque control means. CONSTITUTION:A torque computing unit TCL 58 obtains a stability factor and the speed and the lateral acceleration with the speed of rear wheels in right and left to be detected by sensors 66, 67 and a steering angle to be detected by a sensor 70, and computes the acceleration fore and aft of the target on the basis of the target lateral acceleration to be decided with the stability factor and the lateral acceleration and the speed. Next, the TCL 58 obtained the standard driving torque on the basis of the acceleration fore and aft of the target and a difference between that acceleration fore and aft of the target and the fore and aft acceleration working to a weight of a car body, an effective radius of a wheel, a road load torque and a vehicle. An ECU 54 controls the open degree of a throttle valve 15 so as to get the driving torque of an engine 11 corresponding to the standard driving torque. The lateral acceleration is thereby restricted appropriately, and a vehicle can 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 according to the magnitude of lateral acceleration generated when a vehicle turns, and to drive the vehicle safely. The present invention relates to a method for controlling the output of a vehicle.

<Prior art> When the road surface conditions change rapidly while the vehicle is running, or when the vehicle is traveling on a slippery road surface with a low coefficient of friction, such as a snowy or frozen road, the drive wheels may spin. Vertical alignment of the vehicle becomes extremely difficult.

In such a case, it is extremely difficult, even for an experienced driver, for the driver to adjust the amount of depression of the accelerator pedal and delicately control the output of the engine so that the drive wheels do not spin.

Similarly, when a vehicle is traveling on a turning path, a centrifugal force corresponding to the lateral acceleration in the direction perpendicular to the direction of travel is generated.
vl@ If the speed of the vehicle is too high for the road,
There is a risk that the tire's grip strength will be exceeded and the vehicle will skid.

In such cases, in order to reduce the engine output appropriately and drive the vehicle safely with a turning radius that corresponds to the turning path, it is especially important to In cases where the size of the vehicle is gradually decreasing, extremely advanced driving skills 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 idling state of the driving wheels is detected, and when the idling of the driving wheels occurs, the output of the engine is forcibly reduced, regardless of the amount of depression of the accelerator pedal by the driver. Or an output that detects the lateral acceleration of the vehicle and forcibly reduces the engine output before the turning limit at which the vehicle becomes difficult or unable to turn, regardless of the amount of accelerator pedal depression by the driver. A control device is considered, and the driver can select between driving using this output control device as necessary and normal driving in which the engine output is controlled according to the amount of depression of the accelerator pedal. It has been announced.

Among the methods related to vehicle output #J control based on such a viewpoint, a conventionally known method detects, for example, the rotation speed of the driving wheel and the rotation speed of the driven wheel, and calculates the difference between these rotation speeds. The engine drive torque is controlled based on the slip amount, or the engine drive torque is controlled based on the amount of yawing of the two vehicles (hereinafter referred to as yaw rate). This is how it was done.

In other words, in the latter method, the amount of yawing, etc. that mainly occurs during high-speed sharp turns of the vehicle:; Since the higher the vehicle speed and the sharper the turn, the more rapidly the amount of yawing etc. tends to increase, the yaw rate is measured using vibration sensors, acceleration sensors, etc. is detected or exceeds a predetermined value, the driving torque of the engine is reduced.

Note that by using this output control device, it is also possible to reduce system problems 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. It is not possible to control the engine's drive torque until after yawing, etc. of the vehicle actually occurs.

Therefore, in a vehicle equipped with a conventional turning control device, it is basically impossible to overcome the control delay. There was a risk that it would be impossible to run through in some cases.

Means for Solving the Problems> The configuration of the present invention for solving the above problems is as follows: In a vehicle having a torque control means that reduces the driving torque of the engine independently of the operation by the driver, the circumferential speed of the left and right driven wheels. The lateral acceleration acting on the vehicle, the vehicle speed, and the stability factor are calculated using the difference between
A target longitudinal acceleration is calculated based on the lateral acceleration and the vehicle speed, and the target longitudinal acceleration, vehicle weight, and wheel effective radius are calculated.
The basic drive torque is calculated based on the road load torque, the difference between the longitudinal motion mode acting on the vehicle and the target longitudinal acceleration, and the drive torque of the engine is adjusted to a value corresponding to the basic drive torque. The present invention is characterized in that the operation of the torque control means is controlled.

Function> The torque calculation unit calculates the stability factor, vehicle speed, and lateral acceleration from the left and right rear wheel speeds and the turning angle of the 1st rudder axle, uses these to set the target drive torque, and controls this using electronic control. Output to 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.

〈Real M! i Example> As shown in FIG. 1 showing the concept of an embodiment in which the vehicle output control method according to the present invention is applied to a front-wheel drive vehicle, and FIG. 2 showing the schematic structure of the vehicle, the combustion of the engine 11 is In the middle of the intake pipe 13 connected to the combustion chamber 12, there is a throttle valve 15 that changes the opening degree of the intake passage 14 formed by the intake pipe 13 and adjusts the amount of intake air supplied into the combustion chamber 12. A throttle body 16 incorporating the 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 the throttle shaft 17, which has the throttle valve 15 integrally fixed to the throttle body 16, rotate. Supported for free movement.

An accelerator lever 18 and a throttle lever 19 are coaxially fitted into one end 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 accelerator lever 18 and the throttle shaft 1.
It is rotatable relative to 7. Further, a washer 23 and a nut 24 attached to one end of the throttle shaft 17 prevent 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 26.
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
This means that when the throttle lever 19 is rotated in the direction in which the throttle valve 15 opens, or when the accelerator lever 18 is rotated in the direction in which the throttle valve 15 is closed, the positions W are such that they lock with each other. Set in relationship.

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 cylindrical spring receivers 32 fitted to the throttle shaft 17.
, 33, and is mounted coaxially with this throttle shaft 17. 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 18 via the collar 28 to urge 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 is connected to the tank 41 via a connecting pipe 42 , and a reverse pipe that only allows air to move from the vacuum tank 43 to the surge tank 41 is provided between the vacuum tank 43 and the connecting pipe 42 . A stop valve 44 is interposed. This results in
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 that communicates with the intake path @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, the torque control g magnetic valve 51 includes a spring 53 that biases the plunger 52 to open the pipe 50.

1 to the two torque control solenoid valves 46 and 51.
The electronic control units 54 (hereinafter referred to as ECUs) that control the operating states of the torque control solenoid valves 4 and 11 are connected to each other, and the torque control solenoid valves 4
The ON and OFF of energization for 6°51 is controlled by duty, and in this embodiment, the entirety of these constitutes 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, when the duty rate of the torque control solenoid valves 46 and 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 15 is closed regardless of the amount of depression of the accelerator pedal 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 to vR, the opening degree of the throttle valve 15 is changed regardless of the amount of depression of the accelerator pedal 26, and the drive torque of the engine 11 can be adjusted arbitrarily. Can be adjusted.

The ECU 34 includes a crank angle sensor 55 that is attached to the engine vi11 and detects the engine speed, a throttle opening sensor 56 that is attached to the throttle body 16 and detects the opening of the throttle lever 19, and a throttle opening sensor 56 that is attached to the throttle body 16 and detects the opening of the throttle lever 19. An idle switch 57 that detects the fully open state is connected, and output signals from the crank angle sensor 55, throttle opening sensor 56, and idle switch 57 are sent, respectively.

Additionally, a 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 5
7, an accelerator opening sensor 59 is attached to the throttle body 1111 to detect 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 and 61, which are drive wheels, respectively. and,
Rear wheel rotation sensors 66,67 that detect the rotational speeds of a pair of left and right rear wheels 64,65, which are driven wheels, and a vehicle 68.
A steering angle sensor 70 that detects the turning angle of the steering shaft 69 when turning with reference to the straight-ahead state of the steering wheel is connected to the steering angle sensor 70, and output signals from these sensors 59, 62, 63, 66, 67, and 70 are sent, respectively.

The ECU 54 and the TCL 58 are connected via a communication cable 71), and the ECU 34 receives 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 amount of intake air. is sent to TCL58. 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, the target drive torque T of the mechanic 1 when slip control is performed in this embodiment. g, and the target drive torque T of the engine 11 when turning control is performed. These two target driving torques T are always calculated in parallel by the TCL 58.

,, The optimum final target drive torque To is selected from ToH, and 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 Ml first reads the initial value δ of the steering shaft turning position, resets various flags, or sets the sampling period of this control. Initial settings such as starting the main timer count every 15 milliseconds are performed.

Then, in M2, the TCL 58 calculates the vehicle speed etc. based on the detection signals from various sensors, and then learns and corrects the neutral position δ of the steering shaft 69 in M3. The neutral position δ of the steering shaft 69 of the vehicle 68, and the initial value δ each time the ignition key is turned on. , is read, but this initial value δ1° is learned and corrected only when the vehicle 68 satisfies the straight running condition described later, and this initial value δ is learned and corrected until the ignition key is turned off. It has become.

Next, TCL58 is M4 with front wheels 60, 61 and rear wheels 64.
. ,
The target drive torque T of the engine 11 when turning control is performed using M5. Calculate H'eR.

Then, at M6, the TCL 58 determines the optimum final target drive torque T from these target drive torques Tos'Tas. is selected by the method described below, and then the EC is selected so that the drive torque of the engine 11 becomes this final target drive torque T0.
U34 controls the duty ratio of the pair of torque control solenoid valves 46 and 51, thereby allowing the vehicle 68 to travel smoothly and safely.

In this way, the driving torque of the engine 11 is controlled by Ml until the countdown of the main timer ends, and from then on, the driving torque of the engine 11 is controlled by Ml.
At step 8, the main timer starts counting down again, and steps M2 to M8 are repeated until the ignition key is turned off.

Neutral position δ of the steering shaft 69. The reason why is learned and corrected in step M3 is that the amount of turning of the steering shaft 69 and the steering angle change when the toe-in adjustment was performed in the previous @960, 61 when the vehicle 68 was USed, or due to secular changes such as wear of the steering gear (not shown). This is because a deviation may occur between the actual steering angle δ of the front wheels 60 and 61, and the neutral position δ of the steering shaft 69 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 C1 using the following formula (1).

v + v ■=*L Fl p+ 2=41) However, in the above equation, V RL p ■** is the peripheral speed of the pair of left and right rear wheels 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) IV,
, -V□1.

Thereafter, the TCL 58 determines at C3 whether the vehicle speed V is greater than a preset g value VA. This operation C is necessary because the rear wheel speed difference Vl'lL"11111 due to steering cannot be detected unless the vehicle 68 reaches a certain high speed, and the threshold value VA depends on the driving characteristics of the vehicle 68. Based on experiments etc., for example, 20km/h
It is set as appropriate, such as +.

Then, when it is determined that the vehicle speed V is above the H value V, TCL5g is set at C4 to rear wheel speed difference IVFIL-v1.
It is determined whether I1.11 is smaller than a preset threshold value V, such as 0.1 km/hour, that is, whether the vehicle 68 is traveling straight. Here, the reason why the threshold value ■Y is not set to 0km/hour is that if the left and right rear wheels 64 and 65 have unequal tire air pressure, even though the vehicle 6B is traveling straight, the rear of the left and right rear wheels @64.65 Circumferential speed v
1. This is because the lL and v-works are different.

At this step 04, the rear wheel speed difference is 1 vRL 'l'l
If it is determined that F' is less than or equal to g*vB, TCL
58 (at YOC5, the current yI! rudder shaft turning position δ1 is the previous steering shaft turning position δ detected by the steering angle sensor 64)
7. Determine whether n-11 is the same as n-11. At this time, it is desirable to set the turning detection resolution of the steering shaft 69 by the steering angle sensor 70 to around 5 degrees, for example, so as not to be affected by the driver's camera shake or the like.

At 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 δ1°-1, the TCL 58 determines at C6 that the current vehicle 68 is traveling straight, and the TCL 58 uses a built-in learning tool (not shown). A timer starts counting and continues for example for 0.5 seconds.

Next, the TCL 58 determines at C7 whether 0.5 seconds have passed since the learning timer started counting, that is, whether the vehicle 68 has continued to go 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.

Then, when it is determined that 0.5 seconds have passed since the learning timer started counting, the TCL58 determines whether the steering angle neutral position learned flag F is set in C8), that is, if the current learning control is the first time. Determine whether it exists or not.

At step 08 of O, the steering angle neutral position learning completed flag FH
If it is determined that the current steering shaft turning position δm (nl) is not set, C9 considers the current steering shaft turning position δm (nl) to be the new neutral position δ of the steering shaft 69 and I'I(n), and stores this in the memory in the TCL 58. Read and set the steering angle neutral position learned flag FM.

In this way, a new neutral position WδM (
After setting nl, the neutral position δ□ of this steering shaft 69 is set.

The turning angle δ8 of the steering shaft 69 is calculated based on , while the count of the learning timer is cleared at C1o, and the steering angle neutral position learning is performed again.

In step C8, the steering angle neutral position M learned flag F;
is set, and it is determined that the steering angle neutral position learning is being performed for the second time or later, the TCL 58 determines the current steering shaft turning position δ11. is equal to the previous neutral position δ of the steering shaft 69, that is, δ = δ.
l m (
n) Determine whether the current steering shaft turning position δminl is the same as the previous steering shaft 6.
9 neutral position δ□. If it is determined that it is equal to -1, then
The process returns to step C10 and the next steering angle neutral position learning is performed again.

In step C11, the current steering shaft turning position δ1. ,,
is not equal to the previous neutral position δ of the steering shaft 69 due to play in the steering system, etc. (if n-11 is determined, the current steering shaft turning position δ1°.

is not judged as the new neutral position δ□nl of the steering shaft 69, but is set in advance with respect to the previous steering shaft turning position δm(n-1), for example, 5 degrees corresponding to the detection resolution of the steering angle sensor 70. The new neutral position δ6 of the steering shaft 69 is obtained by subtracting or adding the correction limit amount Δδ of the degree. ．． 1, and this is read into the memory within the TCL 58.

In other words, the TCL 58 changes from the current steering shaft turning position δ1o to the previous neutral position δMlr+- of the steering shaft 69 at C12.
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 step 012 is smaller than the negative correction limit amount -Δδ, a new steering axis 6 is set in step C13.
9 neutral position δ,. , from the previous neutral position δ of the steering shaft 69 and the negative correction limit amount −Δδga(n−11), δ = δ −Δδ M(nl M (changed to n−11, − learning correction per time) Care is taken to ensure that the amount does not unconditionally increase to the negative side.

As a result, even if an abnormal detection signal is output from the steering angle sensor 70 for some reason, the steering shaft 69
Since the neutral position δ of , does not suddenly change from 1, it is possible to quickly respond to this abnormality.

On the other hand, if it is determined that the value subtracted in step C12 is larger than the negative correction limit amount -Δδ, then in step C14 the current steering shaft turning position δ6. . , from the previous steering axis 69
Neutral position δ8. . It is determined whether the value obtained by subtracting -1° is larger than the positive correction limit amount Δδ. And this C
If it is determined that the value subtracted in step 14 is larger than the positive correction limit amount Δδ, the new neutral position δm of the steering shaft 69 (nl is set as the previous neutral position δ of the steering shaft 69) in C15. Positive correction gate opening (n-1) The limit amount Δδ is changed to δ = δ + Δδ M fnl gate 1n-I+ to ensure that the learning correction amount per - time does not unconditionally increase to the positive side.

As a result, 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 will not change suddenly, making it possible to quickly respond to this abnormality. .

If 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 is changed to the new neutral position δ of the steering shaft 69 in step C16.
,. Read it out as is.

Therefore, when the stopped vehicle 68 starts with the front wheels 60, 61 left in the turning state, as shown in FIG.
Neutral position δ of the steering shaft 69. When learning control is performed for the first time, the initial value δ of the steering shaft turning position in the step Ml described above
Although the amount of correction from 1° is very large, the neutral position δ of the steering shaft 69 from the second time onward is suppressed by the operation divided into steps C13 and C14.

In this way, the neutral position δ of the steering shaft 69 is established. After learning and correcting the vehicle speed V and the circumferential speeds of the front wheels 60, 61, V, L, V,
Target drive torque T when performing slip control that regulates the drive torque of the engine 11 based on the difference from FI. Calculate S.

By the way, in order to effectively use the driving torque generated by the engine 11 (power), as shown in FIG. 7, which shows the relationship between the coefficient of friction between the tires and the road surface and the slip ratio of the tires
The front wheels 60.61 are adjusted so that the slip rate S of the tires of the front wheels 60.61 during running is at or near the target slip rate S0 corresponding to the maximum value of the coefficient of friction between the tires and the road surface.
It is desirable to adjust the slip amount S of the vehicle 61 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 (n-11 Gx) of the vehicle 68 using the following formula from the current vehicle speed V calculated using the above formula (1) and the vehicle speed V calculated - times ago. .

-v G=+nl+n-1 × 3.6・Δt-g However, Δtζ is 15 which is the sampling period of the main timer.
In milliseconds, g is the acceleration due to gravity.

And the driving torque T of the machine WR11 at this time.

is calculated by the following formula (2).

T =G −W −r×T −(2)
a xp b Here, GxF is the modified longitudinal acceleration obtained by passing the change in the longitudinal acceleration Gx described above through a low-pass filter to delay it.

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 Gx of the vehicle 68 and changes the slip rate S of the tire. Target slip rate S corresponding to the maximum value of the coefficient of friction with the road surface.

Or, even if the tire is about to deviate from the vicinity, the target slip rate S is set so that the tire slip rate S corresponds to the maximum value of the Jl friction coefficient between the tire and the road surface. It has a function of modifying the longitudinal acceleration Gx so as to maintain it at or near the same value.

In addition, C; the vehicle body 11r has the effective radius of the front wheels 60, 61(r), T- is the running resistance, and this running resistance T□ can be calculated as a function of the vehicle speed V, but in this embodiment, the 8th
It is obtained from a map as shown in the figure.

On the other hand, while the vehicle 68 is accelerating, it is normal for the wheels to always have a slip amount of about 3% relative to the Ri surface, and when driving on a rough road such as a gravel road, The target slip rate S is higher than when driving on a μ road. Generally, the maximum value of the coefficient of friction between the tire and the road surface is large. Therefore, the target drive wheel speed V1o, which is the circumferential speed of the front wheels 60.61, is calculated by the following equation (3), taking into consideration such slip amount and road surface conditions.

V = 1.03 ・V+V =-(
a) However, VK is a road surface correction amount set in advance corresponding to the modified longitudinal acceleration GXF, and modified #rearward motion speed GX
1 tends to increase stepwise as the value of
I'm looking for.

Next, vehicle speed V and target drive wheel speed ■. The slip amount S, which is the difference between
Calculate according to 4).

vFL+v□ "" 2 -vFO- (4) Then, as shown in equation (5) below, this slip amount S is integrated while the integral coefficient is multiplied by 1 every sampling period of the main timer, and the target drive torque T is obtained. Integral correction torque T, (however, T,
≦0) is calculated.

T=Σ K-5 (5) 1 , , + +11 Similarly, the target drive torque T is proportional to the slip amount S as shown in equation (6) below. Against S! IJI! The proportional correction torque Tp for alleviating the l delay is calculated while being multiplied by the proportionality coefficient Kp.

T=-5 (6) Then, using the above formulas F2), (51, (61), the target drive torque T0. of the machine R11 is calculated by the following formula (7).

In the above equation, ρ 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 first calculates the target drive torque T09 by detecting and calculating the various data described above at Sl, but this calculation operation is not performed manually. This is done regardless of switch operation.

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 TCL58 determines the amount of slip of the front wheels of 60°61 in S3. A threshold value preset by S,
For example, it is determined whether the speed is greater than 2 km/hour.

In these 83 steps, the slip amount S is 2 k+m/hour.
If it is determined that the slip amount S is larger than 0.2 g, the TCL 58 determines in S4 whether the rate of change Gs of the slip amount S is larger than 0.2 g.

In these 84 steps, the slip amount change rate G is 0.2g.
If it is determined that the flag is larger than , the slip control flag Fs is set in S5, and the slip control flag Fs is set in S6.
It is determined again whether or not 6 is set.

If it is determined in step 86 that the slip control flag F is set, the target drive torque T of the engine 11 is determined in S7. S is the target drive torque T for slip control calculated in advance using equation (7). Adopt S.

Also, in the step S6, the slip control flag Fs
If it is determined that the TCL58 has been reset, the TCL58
is huge #X drive torque T. 9, the maximum torque of the m control 11 is outputted at 58, and as a result, the ECU 34 lowers the duty ratio of the torque control solenoid valves 46, 51 to 0%. Generates driving torque according to the amount.

Note that the reason why the TCL 58 outputs the maximum torque of the engine 11 in this step S8 is due to the E
The CU 54 always sets the duty rate of the torque control solenoid valves 46, 51 to the 0% side, that is, the torque control solenoid valves 46, 51.
This is to ensure that the engine 11 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 2 km/h, or S
If it is determined in step 4 that the slip amount change rate GS is smaller than 0.2 g, the process directly proceeds to step S6, and TCLS8 sets the maximum torque of the engine 11 as the target drive torque T in step 58. This causes the ECU 34 to output torque f! 111 official solenoid valve 46
, 51 to the 0% side, the engine ill 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 fP15 is fully closed.

If it is determined in step S9 that the idle switch 57 is on, since the driver has not depressed the accelerator pedal 26, the slip control flag F9 is reset in step 510, and the process moves to step S6.

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

Note that if the driver does not operate the manual switch for selecting the slip alD, 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 calculates the stability factor A of the vehicle N68 from the steering shaft rotation angle δ8 and the vehicle speed V, and calculates the acceleration in the longitudinal direction of the vehicle body so that the vehicle 68 does not undergo extreme understeering. That is, the target longitudinal acceleration Gx0 is set based on the lateral acceleration G7 corresponding to the stability factor A. Then, target drive torques of the engine 11 corresponding to this target longitudinal acceleration Gx0 are determined, and these target drive torques are output to the ECU 34.

By the way, the lateral acceleration G and l of the vehicle 68 and the rear wheel speed difference 1v,
Although it can be actually calculated using L-v□l,
By using the steering shaft turning angle δ8, it is possible to predict the value of the lateral acceleration GY acting on the vehicle 68, which has the advantage of allowing quick control.

However, depending on the steering shaft turning angle δ8 and the vehicle speed V,
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, i of the machine wJ11 desired by the driver can be determined from the amount of depression of the accelerator pedal 26, and the target drive torque of 411-11 can be set by taking this required drive torque Td into consideration. desirable. Furthermore, if the increase or decrease in the target drive torque of the engine 11, which is set every 15 milliseconds, is extremely large, shocks will occur as the vehicle 68 accelerates or decelerates, resulting in a decrease in ride comfort. If the increase or decrease in the target drive torque of the engine 11 becomes large enough to cause a decrease in the ride comfort of the vehicle 68, it is also necessary to regulate the increase or decrease in the target drive torque.

As shown in FIG. 11, which shows a calculation block for turning control in consideration of the above knowledge, the TCL 58 calculates the vehicle speed from the outputs of the pair of rear wheel rotation sensors 66 and 67 using the above formula (1).
At the same time, the lateral acceleration GY is calculated from the following equation (8).

1vMFI ”FIL v ,,,(s
lt b [where b: tread] Next, based on the detection signal from the steering angle sensor 70, the steering angle δ of the front wheels 60, 61 is calculated using the following formula (9), and the calculated lateral acceleration G is filtered. Then, the filtered lateral acceleration GV1 is obtained.

δ8 δya□ ...(9
)ρ.

Furthermore, I asked for *2i! Stability factor A is calculated using V, lateral acceleration GY□ steering angle δ, and the following equation 4.

[However, l: wheel pace]

The TCL 58 stores in advance a map showing the relationship between the stability factor A and the target lateral acceleration Gv0 as shown in block B1. Therefore, the above (III!
The stability factor A obtained using equation 1 is applied to this map to read the target lateral acceleration GYO at this time.

Next, use the following formula 01) to calculate the target longitudinal acceleration G. Find out.

Furthermore, the vehicle speed V is differentiated to determine the longitudinal acceleration G8 actually acting on the vehicle.

Based on the target longitudinal acceleration and longitudinal acceleration Gx thus obtained, the reference drive torque T of the machine [11] is determined.

[However, pH: Steering gear gear ratio]

is calculated by the following formula (12-1) or (12-2).

However, road load (Road-
Load) torque, and in this example, block B
It is obtained from the map shown in 2.

In addition, W is the vehicle weight, r is the effective radius of the wheel, and ρ1 is the ia
Reduction ratio (rotation ratio of drive wheels to engine speed), ρ,
is a differential gear reduction ratio, KP is a constant for proportional control, and K1 is a constant for integral control.

In the above-mentioned equation (12-1), the proportional correction term Kp (Gxo-Gx) for proportional control is taken into account, and further (12-2
), the integral correction term ΣKP [Gxo-Gx) is also taken into consideration in the calculation, so that an accurate reference drive torque T can be obtained.

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

On the other hand, the engine rotation speed N5 detected by the crank angle sensor 55 and the accelerator opening degree θ detected by the accelerator opening degree sensor 59. Based on this, the required driving torque Td desired by the driver is determined from a map as shown in block B3, and then the required driving torque T6 is multiplied by (1-α) by the corrected required driving torque corresponding to the weighting coefficient α. Calculated by For example, when α is set to 0.6, the ratio of the reference drive torque T and desired drive torque Td is 6:4.

Therefore, the target drive torque T of the engine 11. H is calculated using the following formula α1.

T = α・Tll+(1−α)・T6 ...(1
The third vehicle 68 is provided with a manual switch (not shown) for the driver to select turning control, and when the driver selects turning control by operating this manual switch, the turning control described below is performed. It is designed to perform operations.

Target drive torque T for this turning control. As shown in FIG. 12, which shows the control flow for determining H, the target drive torque T is determined by detecting and calculating the various data described above in H1. , , I are calculated, but this operation is performed independently of the operation of the manual switch.

Next, whether or not the vehicle 68 is under turning control at H2;
That is, it is determined whether the turning control flag FCH is set. At first, since turning control is not in progress, it is determined that the turning control flag F is in the reset state, and H3
Target drive torque T. It is determined whether H is less than or equal to a preset threshold, for example (Td-2). In other words, vehicle 68
Target drive torque T even when traveling straight. H can be calculated, but its value is usually much larger than the driver's required drive torque T. However, since this required drive torque T6 generally becomes smaller than C when the vehicle 68 turns, the target drive torque T. The time when H becomes equal to or less than the IJ value (Td-2) is determined as a condition for starting turning control.

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

At step H3, the target drive torque T is 11! (Td
-2) If it is determined that it is below, the TCLS8 determines in H4 whether or not the idle switch 57 is in the off state.

If it is determined in step H4 that the idle switch 57 is off, that is, that the accelerator pedal 26 is depressed by the driver, the turning control flag F is set in step H5.
. H is set. Next, in H6, it is determined whether the steering angle neutral position learned flag FM is set, that is, the reliability of the steering angle δ detected by the steering angle sensor 70.

If it is determined in step H6 that the steering angle neutral position learned flag F8 is set, it is determined again in step H7 whether or not the turning control flag FCH is set.

In the above procedure, since the swing control flag FCM is set in step H5, it is determined that the swing control flag F0 is set in step H7, and
The target drive torque T of the 03 formula previously calculated in 8. H is the target drive torque T for turning control. be hired as a

On the other hand, if it is determined in step H6 that the steering angle neutral position learned flag FH is not set, then the equation (9) ζ
Since the steering angle δ calculated by the iron is not reliable, the target drive torque ToH4 calculated using formula 01! Not adopted, TCL
58 target drive torque T. H, the maximum torque of the engine 11 is output at U9, and the ECU 54 outputs the torque fIJJI! I! @Reducing the duty rate of the solenoid valve 46, 51 to the 0% side.As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

Further, the target drive torque T is set in step H3. If it is determined that H is not below the threshold '1m [(T-21), the system moves from step H6 or H7 to step U9 without moving to turning control, and sets the maximum torque of engine 11 as TCL58+ and target drive torque T08. This outputs the ECU
34 lowers the duty ratio of the torque control electromagnetic valves 46 and 51 to 0%, and as a result, the 8i valve 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

Similarly, even when 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 ToH, With this) +ECU 54 is the torque control solenoid valve 46
．． As a result, the engine 11 generates a driving 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 turning control flag F is set, the target drive torque T calculated this time is determined in Hlo. ,.

The difference between the target drive torque T and the previously calculated target drive torque T is 0 Hin.
-11 Determine whether ΔT is larger than a preset allowable increase/decrease amount T. This allowable increase/decrease tTK is an amount of torque change that does not make the occupant feel the acceleration/deceleration of the vehicle 68, and for example, the target longitudinal acceleration Gxo of the vehicle 68 is changed to 0.0% per second.
If you want to keep it to 1g, (12-1), (12
- Use the 21 formula.

The target drive torque T calculated this time in step TIO (above). 1. ,, and the previously calculated eye I [dynamic torque T
If it is determined that the difference ΔT is not larger than the preset increase/decrease 0H (n-11 allowable amount TK), Hll will change the target drive torque T. It is determined whether the difference ΔTOH (n-1) from

At step Hll, the current target drive torque T and the previously calculated target drive I/lux T. □. -1+Hinl If it is determined that the difference ΔT is larger than the negative increase/decrease tolerance T7, the target drive torque T calculated this time and the target drive torque T calculated last time. ,. -110H(nl) Since the absolute value 1ΔT1 of the difference from
The target driving torque is T. Adopted as H.

Also, the target drive torque T calculated this time in step Hll. ,. If it is determined that the difference ΔT between , and the previously calculated target drive torque T is not larger than the negative increase/decrease tolerance oM(r+-11 1), the current target drive torque T.1.IL, , l is determined in H12. Set by the formula below.

T = T - T OHfnl OHln-11K In other words, the target drive torque To calculated last time. -1l is regulated by the allowable increase/decrease amount TK to reduce the deceleration shock caused by the reduction in the drive torque of the machine rllI11.

On the other hand, the difference ΔT between the target drive torque T calculated this time in the HIO step and the target drive torque T calculated last time is the allowable increase/decrease amount T
If it is determined that this is the above, the current target of 1J will be set in H2S.
AtD torque T. H(nl is set by the following formula.

T = T + T OH (nl ON +n -11K, that is,
In the case of increase in drive torque, the target drive torque T calculated this time is similar to the case of decrease in drive torque described above. 6. , l and the previously calculated target drive torque T. H(difference Δ from n-11
If T exceeds the allowable increase/decrease amount 1, the previously calculated target drive torque T. The increase/decrease increase/decrease to H-1 is regulated by the allowable increase/decrease amount TK, thereby reducing the acceleration shift caused by the increase in the drive torque of the machine 1111.

In this way, the target drive torque T. Steering shaft turning angle δ8, target longitudinal acceleration GX0, and target imperial torque T when the increase/decrease of H is regulated. As shown in FIG. 13, which shows the state of change between H and the actual longitudinal acceleration G8 with a solid line, 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 I! It can be seen that the change in jG is smooth, and the acceleration/deceleration shift has been eliminated.

The target drive torque T is obtained as described above. When H is set, the TCL58 achieves this target drive torque T at HI3. It is determined whether H is larger than the driver's requested driving torque Td.

Here, turn [+Medium flag F. If H is set, target drive torque T. Since it is not larger than the required drive torque Td, it is determined at H2S whether the idle switch 57 is in the on state.

If it is determined in step H2S that the idle switch 57 is not in the on state, the turning control is required, so the process moves to step H6.

Further, the target drive torque T is set in step H14. If it is determined that H is larger than the driver's requested driving torque Td, this means that the turning movement of the vehicle 68 has been completed, so the TCL 58 sets the turning control flag F at H2S. Reset H. Similarly, if it is determined that the idle switch 57 is in the ON state at the H2S step, the accelerator pedal 26 is not depressed, so the H2S step is determined to be in the ON state.
Move to step S and turn flag F0 during turning flJ11J
Reset □.

) At T16, the turning control flag F is set. When N is reset, the TCL 58 outputs the maximum torque of the engine 11 at HI3 as the target drive torque ToH, and thereby the EC
As a result of U 54 lowering the duty ratio of the torque control solenoid valves 46 and 51 to 0% side, the engine 1g 111 changes the engine 11 according to the amount of depression of the accelerator pedal 26 by the M driver.
generates a driving torque of

Note that it is naturally possible to ignore the driver's requested drive torque Td in order to simplify the turning control procedure described above, and in this case, the target drive torque can be set to the standard that can be calculated using the formula It is sufficient to adopt the driving torque T3.Also, even when the driver's required driving torque T6 is taken into account as in this embodiment, the weighting coefficient Q is not set to a fixed value, but as shown in FIG. The value of the coefficient Q may be gradually decreased with the passage of time after the start of control, or the 15th
As shown in the figure, the ratio of the driver's requested drive torque T may be gradually increased by gradually decreasing the torque T according to the vehicle speed. Similarly, as shown in FIG. 16, 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 a as the value of 8 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 0, allowable increase/decrease amount T
This target drive torque T is determined by K. Although the aim is to restrict H, this restriction may also be applied to the target longitudinal acceleration G8°. When the allowable increase/decrease amount in this case is GK,
The calculation process for the target longitudinal acceleration G at the nth time is shown below.

xo (nl XO+n-11>GK, G
-G G =G +G xo (r+l XO1n-11KXO(I
ll XO (if n-11<-〇・G
-G G =G -G .

The TCL58 uses these two target drive torques Tos, To
H to the optimal final target drive torque T. 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. , is smaller, the final target drive torque T for slip control and turning control is determined in this order. Please select ζ.

<Effects of the Invention> According to the vehicle output control method of the present invention, the magnitude of the stability factor 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 stability factor 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 magnitude of the lateral acceleration determined from the The magnitude of lateral acceleration can be estimated. 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.

Further, by using this torque control device, it is also possible to reduce shifting during shifting in an automatic transmission.

[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 neutral position learning and 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 flow chart showing the flow of slip control, Fig. 11 is a block diagram showing the procedure for calculating the target drive torque, and Fig. 12 is a flowchart showing the flow of turning control, Fig. 13 is a graph showing the relationship between steering shaft turning angle, target drive torque, and longitudinal acceleration, and Figs. 14, 15, and 16 are time and weighting after the start of control. 3 is a graph showing the relationship between the coefficients of and the coefficients of . Also, in the figure, 11 is the engine, 12 (: combustion chamber, 13 is the intake pipe, 14 is the intake passage, 15Lt throttle valve, 17
is the throttle shaft, 18 is the accelerator lever, 19 is the throttle lever, 26 is the accelerator pedal, 27 is the cable, 2
9 is a claw portion, 30 is a stopper, 36 is an actuator, 3
8 is a control rod, 42 is a connecting pipe, 43 is a vacuum tank, 44 is a check valve, 45 and 50 are pipes, 46.51 is a torque control solenoid valve, and 54 is an ECU. 55 is a crank angle sensor, 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, 62 and 63 are front wheel rotation sensors, 64° and 65 are rear wheels, 66, 67 is a rear wheel rotation sensor, 68 is a vehicle, 69 is a steering shaft, 70 is a steering angle sensor, 71 is a communication cable, A is a stability factor, FH is a steering angle neutral position learned flag, F. is the slip control flag, FcH is the turning control flag,
G is the target longitudinal acceleration, Gxo is the longitudinal acceleration, GY is the lateral acceleration, Gv0ζ is the target lateral acceleration, g It 11i force acceleration, TO,! Target drive torque for Nislip control, T
08 is the target drive torque, To is the final target drive torque, T
l is the standard drive torque, T is the required drive torque, ■ is the vehicle speed, S is the amount of slip, θ is the accelerator opening, δ1 is the throttle opening, θ7o is the target throttle opening, δ is the front wheel steering angle, δ8 is the aperture angle of the steering shaft, and δ1 is the neutral position of the steering shaft.

Claims (1)

[Scope of Claims] In a vehicle having a torque control means that reduces the driving torque of the engine independently of the operation by the driver, the torque control means acts on the vehicle using the difference in circumferential speed of the left and right driven wheels and the turning angle of the steering shaft. The target lateral acceleration calculated from the stability factor, the vehicle speed, and the stability factor are calculated.
A target longitudinal acceleration is calculated based on the lateral acceleration and the vehicle speed, and the target longitudinal acceleration, vehicle weight, and wheel effective radius are calculated.
Calculate the basic drive torque based on the road load torque, the difference between the longitudinal acceleration acting on the vehicle and the target longitudinal acceleration, and calculate the basic drive torque so that the drive torque of the engine has a value corresponding to the basic drive torque. A vehicle output control method comprising controlling the operation of a torque control means.