JPH04219431A - Output controller of vehicle - Google Patents

Abstract

PURPOSE:To provide an output controller of a vehicle which can drive through a cornering easily and completely by restraining the lateral acceleration of a vehicle which generates at the time of cornering appropriately. CONSTITUTION:There are provided a torque control means which decreases the driving torque of an engine 11 separately from the operation of a driver, a torque computing unit 58 which calculates the lateral acceleration of a vehicle 68 based on a vehicle speed and a steering angle and calculates an aimed driving torque according to the lateral acceleration, and compares the aimed driving torque with the aimed driving torque which has been calculated at previous time for regulating the change in amount of a current aimed driving torque, and an electronic control unit 54 which controls a torque control means so that the driving torque of an engine may become the aimed driving torque.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a vehicle output that quickly reduces engine drive torque in accordance with the magnitude of lateral acceleration that occurs when the vehicle turns, thereby making it possible to perform turning operations easily and safely. Regarding a control device.

0002

[Prior Art] When the road surface conditions change suddenly while the vehicle is running, or when the vehicle runs on a slippery road surface with a low coefficient of friction, such as a snowy or frozen road, the drive wheels may spin. It becomes extremely difficult to control the vehicle.

[0003] In such cases, it is extremely difficult for the driver, even for an experienced 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 a direction perpendicular to the direction of travel is generated, so if the speed of the vehicle relative to the turning path is too high, 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 corresponding to the turning path, it is necessary to reduce the output of the turning path, especially when the exit of the turning path cannot be confirmed or In cases where the radius of curvature is gradually becoming smaller, 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 certain value specific to each vehicle. As a result, the amount of steering increases rapidly, and as mentioned above, safe turning becomes 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.

[0007] 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, it 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. An output control device has been proposed that allows the driver to select between driving using this output control device as needed, and normal driving in which the engine output is controlled according to the amount of depression of the accelerator pedal. What has been done has been announced.

[0008] Among methods related to output control of a vehicle based on such a viewpoint, conventionally known methods detect, for example, the rotational speed of a driving wheel and the rotational speed of a driven wheel, and calculate the difference between these rotational speeds. This is regarded as the amount of wheel slip, and the engine drive torque is controlled according to this slip amount, or the engine drive torque is controlled based on the amount of vehicle yawing (hereinafter referred to as yaw rate). This is what I did.

In other words, in the latter method, the amount of yawing that mainly occurs during high-speed sharp turns of the vehicle tends to increase rapidly as the vehicle speed is higher and the turns are sharper, so vibration sensors, acceleration sensors, etc. When the yaw rate is detected by , or when the yaw rate exceeds a predetermined value, the driving torque of the engine is reduced.

[0010] By using this output control device, it is also possible to reduce shocks during gear changes in an automatic transmission.

[0011]

[Problems to be Solved by the Invention] However, the above-mentioned turning control device reduces or increases the driving force by detecting the condition of the vehicle body, so if the increase or decrease in the driving force is large, it is necessary to apply an acceleration/deceleration shock. This has caused a problem in that the ride quality has deteriorated.

0012

[Means for Solving the Problems] The configuration of the vehicle output control device according to the present invention which solves the above problems includes a torque control means for reducing the driving torque of the engine independently of the operation by the driver, and a steering shaft. A steering angle sensor that detects a turning angle, a vehicle speed sensor that detects the speed of the vehicle, and a lateral acceleration of the vehicle is calculated based on detection signals from the steering angle sensor and the vehicle speed sensor, and the magnitude of the lateral acceleration is calculated. a torque calculation unit that calculates a target drive torque of the engine according to the target drive torque and compares the target drive torque with a previously calculated target drive torque to regulate an increase/decrease in the current target drive torque; and an electronic control unit that controls the operation of the torque control means so that the torque becomes a target driving torque.

[0013] Furthermore, in the torque calculation unit,
Instead of regulating the increase/decrease in the target drive torque, the present invention is characterized in that the increase/decrease in the target longitudinal acceleration, which is determined prior to calculating the target drive torque, is regulated.

[0014] As a torque control means for reducing the driving torque of the engine, it is common to delay the ignition timing, reduce the amount of intake air or fuel supply, or stop the fuel supply. However, as a special type, it is also possible to use one in which the compression ratio of the engine is lowered. Furthermore, by using this torque control device, it is possible to reduce shocks during gear changes in an automatic transmission in addition to controlling the slip of the driving wheels.

[0015]

[Operation] 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 calculates the target drive torque according to the magnitude of this lateral acceleration. This target drive torque is compared with the previously calculated target drive torque, and if the increase/decrease exceeds a predetermined value, the increase/decrease in the target drive torque is regulated and outputted to the electronic control unit. Since the increase/decrease in torque is suppressed within a certain value, acceleration/deceleration shocks are alleviated or prevented.

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. Reduces drive torque to prevent increase in vehicle lateral acceleration.

[0017] The target drive torque is also regulated by regulating the increase/decrease in the target longitudinal acceleration, which is determined prior to calculation of the target drive torque.

[0018]

[Embodiment] As shown in FIG. 1 showing the concept of an embodiment in which the vehicle output control device according to the present invention is applied to a front-wheel drive vehicle, and FIG. 2 showing the schematic structure of the vehicle, a combustion chamber of an engine 11 is shown. A throttle valve 15 is installed in the middle of the intake pipe 13 connected to the combustion chamber 12 to change the opening degree of the intake passage 14 formed by the intake pipe 13 and adjust the amount of intake air supplied into the combustion chamber 12. A throttle body 16 is installed. 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, on which the throttle valve 15 is integrally fixed, are rotatably attached to the throttle body 16. Supported. 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 throttle shaft 17 and the accelerator lever 1
A bush 21 and a spacer 22 are provided between the cylindrical portion 20 of No.
is interposed, so that the accelerator lever 18 is rotatable with respect to the throttle shaft 17. Furthermore, the accelerator lever 18 is separated from the throttle shaft 17 by a washer 23 and a nut 24 attached to one end of the throttle shaft 17.
This prevents it from falling off. Further, an accelerator pedal 26 operated by the driver is connected to a cable receiver 25 integrated with the accelerator lever 18 via a cable 27, and the accelerator lever 18 is moved to the throttle shaft according to the amount of depression of the accelerator pedal 26. It is designed to rotate relative to 17.

On the other hand, the throttle lever 19 is fixed integrally with the throttle shaft 17, and therefore, by operating the throttle lever 19, the throttle valve 1
5 rotates together with the throttle shaft 17. Further, a collar 28 is fitted coaxially and integrally with the cylindrical portion 20 of the accelerator lever 18, and the tip of the throttle lever 19 is engaged with a claw portion 29 formed in a part of the collar 28. A stopper 30 is formed which can be used. The claw portion 29 and the stopper 30 are designed to engage with each other 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. It is set in a certain positional relationship.

A torsion coil spring 3 is provided between the throttle body 16 and the throttle lever 19 for urging the stopper 30 of the throttle lever 19 against the claw portion 29 of the accelerator lever 18 in the direction of opening the throttle valve 15.
1 is mounted coaxially with the throttle shaft 17 via a pair of cylindrical spring receivers 32 and 33 fitted to the throttle shaft 17. Also, throttle body 1
Stopper pin 34 protruding from 6 and accelerator lever 18
A torsion coil spring is also provided between the accelerator lever 18 and the accelerator pedal 26 to press the claw portion 29 of the accelerator lever 18 against the stopper 30 of the throttle lever 19 to bias the throttle valve 15 in the direction of closing, thereby imparting a detent feeling to the accelerator pedal 26. 35
is connected to the cylindrical portion 2 of the accelerator lever 18 via the collar 28.
0 coaxially with the throttle shaft 17.

At the tip of the throttle lever 19,
A distal end portion of a control rod 38 whose base end is fixed to a diaphragm 37 of an actuator 36 is connected. In the pressure chamber 39 formed in the actuator 36, there is a compression coil spring which, together with the torsion coil spring 31, presses the stopper 30 of the throttle lever 19 against the claw portion 29 of the accelerator lever 18 and biases the throttle valve 15 in the direction of opening. 40
is included. And these two springs 31,
The spring force of the torsion coil spring 35 is set to be greater than the sum of the spring forces of the two springs 31 and 40, so that when the accelerator pedal 26 is depressed or the pressure inside the pressure chamber 39 is increased by the spring force of the two springs 31 and 40. The throttle valve 15 will not open unless the negative pressure is greater than the sum of the following.

A surge tank 41 is connected to the downstream side of the throttle body 16 and forms a part of the intake passage 14.
A vacuum tank 43 is in communication with the connecting pipe 42, and the vacuum tank 43 and the connecting pipe 42 are connected to each other.
Between the vacuum tank 43 and the surge tank 4
A check valve 44 is interposed to allow air to move only into the air. 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.

The interior of the vacuum tank 43 and the pressure chamber 39 of the actuator 36 are in communication via a pipe 45, and in the middle of this pipe 45 there is a first torque control valve that is closed when energized. A solenoid valve 46 is provided. In other words, this torque control solenoid valve 46 has piping 45.
A spring 49 is incorporated to bias the plunger 47 against the valve seat 48 so as to close the valve seat 48.

Further, the piping 45 between the first torque control solenoid valve 46 and the actuator 36 includes a piping 50 that communicates with the intake passage 14 on the upstream side of the throttle valve 15.
is connected. A second torque control solenoid valve 51 that is open when not energized is provided in the middle of the pipe 50. That is, this torque control solenoid valve 51 has a spring 5 that urges the plunger 52 to open the pipe 50.
3 is included.

[0026] The two torque control solenoid valves 46, 51
are connected to an electronic control unit (hereinafter referred to as ECU) 54 that controls the operating state of the engine 11, and turns on/off the current to the torque control solenoid valves 46, 51 based on commands from the ECU 54. , OFF are duty-controlled, and in this embodiment, they collectively constitute the torque control means of the present invention.

For example, when the duty rate of the torque control solenoid valves 46 and 51 is 0%, the pressure chamber 39 of the actuator 36 is connected to the intake passage 14 upstream of the throttle valve 15.
The atmospheric pressure becomes almost equal to the pressure inside 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 100%, 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 moves diagonally to the left in FIG. As a result of being pulled upward, 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 electromagnetic valves 46 and 51, the opening degree of the throttle valve 15 can be changed regardless of the amount of depression of the accelerator pedal 26, and the driving torque of the engine 11 can be arbitrarily adjusted.

The ECU 54 includes a crank angle sensor 55 that is attached to the engine 11 and detects the engine rotation speed;
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 closed state of the throttle valve 15 is connected, and output signals from the crank angle sensor 55, throttle opening sensor 56, and idle switch 57 are sent, respectively.

[0029] Also, a torque calculation unit (hereinafter referred to as TCL) that calculates the target drive torque of the engine 11.
58 includes an accelerator opening sensor 59 that is attached to the throttle body 16 together with the throttle opening sensor 56 and the idle switch 57 to detect the opening of the accelerator lever 18, and a pair of left and right front wheels 60, 61 that are driving wheels.
front wheel rotation sensors 62, 6 that respectively detect the rotational speed of the
3, rear wheel rotation sensors 66 and 67 that detect the rotation speeds of a pair of left and right rear wheels 64 and 65, which are driven wheels, respectively, and a steering shaft 6 when turning based on the straight-ahead state of the vehicle 68.
A steering angle sensor 70 for detecting the turning angle of No. 9 is connected, 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 54 receives information on the operating state of the engine 11, such as the amount of intake air, in addition to the engine speed and detection signals from the idle switch 57. Sent to TCL58. Conversely, the TCL 58 sends information regarding the target drive torque calculated by the TCL 58 to the ECU 54.

As shown in FIG. 4, which shows the general flow of control according to this embodiment, in this embodiment, the target drive torque TOS of the engine 11 when slip control is performed and the coefficient of friction, such as on a dry road, etc. The target drive torque TOH of the engine 11 when performing turning control on a relatively high road surface (hereinafter referred to as a high μ road) and a road surface with a relatively low coefficient of friction such as a frozen road or a wet road. The TCL 58 always calculates the target drive torque TOL of the engine 11 when performing turning control on a low μ road (hereinafter referred to as a low μ road), and calculates these three target drive torques TOS, TOH, The optimum final target drive torque TO is selected from TOL, 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 at M1, the initial value δm(o) of the steering shaft turning position is first read, and various flags are reset. Alternatively, initial settings such as starting the main timer count every 15 milliseconds, which is the sampling period of this control, are performed.

Then, in M2, the TCL 58 calculates the vehicle speed V, etc. based on the detection signals from various sensors, and subsequently, the neutral position δM of the steering shaft 69 is learned and corrected in M3. The neutral position δM of the steering shaft 69 of the vehicle 68 is set to an initial value δm every time the ignition key is turned on.
(o) is read, but this initial value δm(o) is learned and corrected only when the vehicle 68 satisfies the straight running condition described later, and this initial value δm(o) remains unchanged until the ignition key is turned off. Learning correction is now available.

Next, TCL58 is M4 with front wheels 60,6
When the target drive torque TOS is calculated when slip control is performed to regulate the drive torque of the engine 11 based on the rotation difference between the engine 1 and the rear wheels 64 and 65, and turning control is performed on a high μ road using M5. Similarly, the target drive torque TOL of the engine 11 when turning control on a low μ road is performed using M6 is sequentially calculated.

Then, at M7, the TCL 58 selects the optimal final target drive torque TO from these target drive torques TOS, TOH, and TOL by a method described later, and then determines that the drive torque of the engine 11 is equal to this final target drive torque TO. As shown, the ECU 54 has a pair of torque control solenoid valves 46.
, 51, thereby controlling the duty rate of the vehicle 68.
The vehicle is designed to run smoothly and safely.

In this way, the driving torque of the engine 11 is adjusted to M8.
control until the main timer countdown ends,
After this, the main timer starts counting down again at M9, and the steps from M2 to M9 are repeated until the ignition key is turned off.

The reason why the neutral position δM of the steering shaft 69 is learned and corrected in step M3 is because the toe-in adjustment of the front wheels 60, 61 is performed during maintenance of the vehicle 68, or due to secular changes such as wear of the steering gear (not shown). This is because a deviation may occur 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 neutral position δM of the steering shaft 69 may change.

As shown in FIGS. 5 and 6 showing the procedure for learning and correcting the neutral position δM of the steering shaft 69, the TCL5
8 calculates the vehicle speed V at C1 using the following formula (1) based on the detection signals from the rear wheel rotation sensors 66 and 67. V=(VRL+VRR)/2
...(1)
However, in the above formula, VRL and VRR are the peripheral speeds of the pair of left and right rear wheels 64 and 65, respectively.

Next, at C2, the TCL 58 calculates the circumferential speed difference between the left and right rear wheels 64, 65 (hereinafter referred to as rear wheel speed difference) |VRL-VRR|. Afterwards, T.
CL58 determines at C3 whether the vehicle speed V is greater than a preset threshold value VA. This operation cannot be performed unless the vehicle 68 reaches a certain high speed.
- This is necessary because VRR| etc. cannot be detected,
The threshold value VA is appropriately set, for example, to 20 km/hour, based on the driving characteristics of the vehicle 68, etc., through experiments and the like.

Then, when it is determined that the vehicle speed V is equal to or higher than the threshold value VA, the TCL 58 adjusts the rear wheel speed difference |V at C4.
RL-VRR｜preset, for example, 0.1km/hour
Whether or not the vehicle 68 is smaller than a threshold value VB such as
Determine whether or not the vehicle is traveling straight. Here, the threshold value V
B is not 0 km/h because the left and right rear wheels 64 and 65
This is because if the air pressures of the tires are not equal, the circumferential speeds VRL and VRR of the pair of left and right rear wheels 64 and 65 will differ even though the vehicle 68 is traveling straight.

[0041] Rear wheel speed difference |VRL at this C4 step
-VRR| is determined to be less than or equal to the threshold value VB,
TCL58 indicates the current steering shaft turning position δm(n) at C5.
It is determined whether or not is the same as the previous steering shaft turning position δm(n-1) detected by the steering angle sensor 70. At this time, be careful not to be affected by the driver's hand shake, etc.
It is desirable to set the turning detection resolution of the steering shaft 69 by the steering angle sensor 70 to, for example, about 5 degrees.

In this step C5, the current steering shaft turning position δm(n) is changed to the previous steering shaft turning position δm(n-1).
If it is determined that the TCL 58 is the same as
A learning timer (not shown) built in 58 starts counting, and this continues for, for example, 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, since 0.5 seconds have not elapsed since the start of counting of the learning timer when the vehicle 68 is initially running, steps C1 to C7 are repeated when the vehicle 68 is initially running.

[0044] When it is determined that 0.5 seconds have elapsed since the start of counting of the learning timer, the TCL58
At step 8, it is determined whether the steering angle neutral position learned flag FH is set, that is, whether the current learning control is the first time.

If it is determined in step C8 that the steering angle neutral position learned flag FH is not set, the current steering shaft turning position δm(n) is changed to the new neutral position of the steering shaft 69 in step C9. Considering the position δM(n), this is TC
Read it into the memory in L58 and set the steering angle neutral position learned flag FH.

After setting a new neutral position δM(n) of the steering shaft 69 in this way, the turning angle δH of the steering shaft 69 is determined based on the neutral position δM(n) of the steering shaft 69.
At the same time, the count of the learning timer is cleared at C10, and the steering angle neutral position learning is performed again.

If it is determined that the steering angle neutral position learned flag FH is set in step C8, that is, it is determined that the steering angle neutral position learning is being performed for the second time or later, TCL5
8 determines in C11 whether the current steering shaft turning position δm(n) is equal to the previous neutral position δM(n-1) of the steering shaft 69, that is, δm(n)=δM(n-1). Determine. Then, the current steering shaft turning position δm(n) becomes the previous neutral position δM(n) of the steering shaft 69.
-1), the process returns to step C10 and the next steering angle neutral position learning is performed again.

If it is determined in step C11 that the current steering shaft turning position δm(n) is not equal to the previous neutral position δM(n-1) of the steering shaft 69 due to play in the steering system, etc. , when the current steering shaft turning position δm(n) is not directly determined as the new neutral position δM(n) of the steering shaft 69, and the absolute value of these differences differs by more than a preset correction limit amount Δδ. , the previous neutral position δM of the steering shaft 82
(n-1) by subtracting or adding this correction limit amount Δδ to the new neutral position δM(n) of the steering shaft 69, which is read into the memory in the TCL 58.

In other words, the TCL 58 determines at C12 that the value obtained by subtracting the previous neutral position δM(n-1) of the steering shaft 69 from the current steering shaft turning position δm(n) is the preset negative correction limit amount -Δδ. Determine whether it is smaller than . and,
If it is determined that the value subtracted in step C12 is smaller than the negative correction limit amount -Δδ, the new neutral position δM(n) of the steering shaft 69 is set to the previous steering shaft 69 in step C13. Neutral position δM (n-1) and negative correction limit amount -Δδ
Therefore, it is changed to δM(n)=δM(n-1)−Δδ to ensure that the learning correction amount per time 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 neutral position δM of the steering shaft 69 does not change suddenly, and this abnormality can be dealt with quickly.

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 δm(n) is changed from the previous steering shaft 69 It is determined whether the value obtained by subtracting the neutral position δM(n-1) of is larger than the positive correction limit amount Δδ. If it is determined that the value subtracted in step C14 is larger than the positive correction limit amount Δδ, the new neutral position δm(n) of the steering shaft 69 is set to the previous steering shaft 69 in step C15. Neutral position δM (n-1) and positive correction limit amount Δδ
Therefore, it is changed to δM(n)=δM(n-1)+Δδ 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 δM of the steering shaft 69 does not change suddenly, and this abnormality can be dealt with quickly.

However, if it is determined that the value subtracted in step C14 is smaller than the positive correction limit amount Δδ,
At C16, the current steering shaft turning position δm(n) is read out as it is as a new neutral position δM(n) of the steering shaft 69.

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 δM of the steering shaft 69 is performed for the first time, the amount of correction from the initial value δm(o) of the steering shaft turning position in step M1 described above is very large; Neutral position δM of shaft 69
is suppressed by the operations in steps C13 and C14.

In this way, the neutral position δM of the steering shaft 69
After learning and correcting, the target drive torque T when performing slip control that regulates the drive torque of the engine 11 based on the difference between the vehicle speed V and the circumferential speeds VPL and VFR of the front wheels 60 and 61.
Calculate the OS.

By the way, in order to make the driving torque generated by the engine 11 work effectively, it is necessary to adjust the speed of the front wheels while running, as shown in FIG. So that the slip rate S of the tires 60 and 61 is at or near the target slip rate SO corresponding to the maximum value of the coefficient of friction between the tire and the road surface.
It is desirable to adjust the slip amount s of the front wheels 60, 61 so as not to impair the acceleration performance of the vehicle 68. Here, the slip rate S of the tire is S=[{(VFL+VFR)/2}-V]/V,
The target drive torque TOS of the engine 11 is set so that this slip ratio S is at or near the target slip ratio SO corresponding to the maximum value of the friction coefficient between the tires and the road surface.The calculation procedure is as follows. be.

First, the TCL 58 calculates the current longitudinal acceleration G of the vehicle 68 from the current vehicle speed V(n) calculated by the above equation (1) and the previously calculated vehicle speed V(n-1).
X is calculated using the following formula. GX = (V(n) −V(n-1) )/(3.6・
Δt·g) However, Δt is 15 milliseconds, which is the sampling period of the main timer, and g is the gravitational acceleration.

[0058] At this time, the driving torque T of the engine 11 is
B is calculated using the following formula (2). TB = GXF・Wb・r+TR
...(2)
Here, GXF is a modified longitudinal acceleration that has been passed through a low-pass filter that delays the change in the longitudinal acceleration GX described 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 GX of the vehicle 68 and changes the slip rate S of the tire between the tire and the road surface. Even if the tire slip rate S corresponds to the maximum value of the friction coefficient, or is about to deviate from the target slip rate SO, the tire slip rate S
It has a function of correcting the longitudinal acceleration GX so as to maintain the target slip ratio SO corresponding to the maximum value of the coefficient of friction between the tire and the road surface or in the vicinity thereof. Further, Wb is the vehicle weight, r is the effective radius of the front wheels 60, 61, and TR is the running resistance. This running resistance TR can be calculated as a function of the vehicle speed V, but in this embodiment, it is calculated as shown in FIG. I'm looking for it from the map.

On the other hand, while the vehicle 68 is accelerating, it is normal that the wheels always slip about 3% with respect to the road surface, and when driving on a rough road such as a gravel road, Low μ
The maximum value of the coefficient of friction between the tires and the road surface corresponding to the target slip ratio SO is generally larger than when driving on a road. Therefore, the target driving wheel speed VFO, which is the circumferential speed of the front wheels 60 and 61, is calculated by the following formula (3), taking into consideration such slip amount and road surface conditions. VFO=1.03・V+VK
...(3)
However, VK is a road surface correction amount set in advance corresponding to the corrected longitudinal acceleration GXF, and the corrected longitudinal acceleration GX
The road surface correction amount V tends to increase gradually as the value of F increases, but in this embodiment, the road surface correction amount V is determined from a map as shown in FIG.
I'm looking for K.

Next, the slip amount s, which is the difference between the vehicle speed V and the target driving wheel speed VFO, is calculated by the following equation (4) based on the above equations (1) and (3). s={(VFL+VFR)/2}-V
FO...(4) And
As shown in equation (5) below, this slip amount s is integrated while being multiplied by an integral coefficient KI at each sampling period of the main timer, and an integral correction torque TI (however, ,TI≦
0) is calculated. TI = Σ KI ・s(i)
…(
5) However, i is from 1 to n.

Similarly, as shown in equation (6) below, the proportional correction torque TP for alleviating the control delay with respect to the target drive torque TOS, which is proportional to the slip amount s, is determined by the proportional coefficient KP.
It is calculated while being multiplied by . TP=KP・s

...(6) And the above (2), (5), (6)
The target drive torque TOS of the engine 11 is calculated using the following equation (7). TOS=(TB-TI-TP+
TR )/(ρm ·ρd ) (7) In the above equation, ρm is the gear ratio of the transmission (not shown), and ρd is the reduction ratio of the differential gear.

The vehicle 68 is provided with a manual switch (not shown) for the driver to select slip control, and when the driver operates this manual switch to select slip control, the following slip control is activated. Perform control operations.

FIG. 1 shows the flow of this slip control process.
1, the TCL 58 first detects and calculates the various data described above in S1 to determine the target drive torque T.
Although the OS is calculated, this calculation operation is performed independently of the operation of the manual switch.

Next, in S2, the slip control flag FS is set.
However, since the slip control flag FS is not set at first, T
The CL 58 determines in S3 whether the slip amount s of the front wheels 60, 61 is larger than a preset threshold value, for example, 2 km/hour.

If it is determined that the slip amount s is larger than 2 km/h in this step S3, the TCL 58 performs step S4.
It is determined whether the rate of change GS of the slip amount s is larger than 0.2 g.

If it is determined in this step S4 that the slip amount change rate GS is larger than 0.2 g, a slip control flag FS is set in S5, and a check is made to determine whether the slip control flag FS is set in S6. It is determined again whether or not.

If it is determined in step S6 that the slip control flag FS is being set, step S7
(7) above as the target drive torque TOS of the engine 11.
The target drive torque TOS for slip control calculated in advance using the formula is adopted.

Further, if it is determined in step S6 that the slip control flag FS has been reset, the TCL 58 sets the engine 11 as the target drive torque TOS.
The maximum torque of
sets the duty rate of the torque control solenoid valves 46 and 51 to 0%.
As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

[0069] Furthermore, in this step S8, the TCL58
The reason why the ECU 54 outputs the maximum torque of the engine 11 is that the torque control solenoid valve 46,
51 is operated to the 0% side, that is, in the direction of cutting off current to the torque control solenoid valves 46 and 51, so that the engine 11 reliably generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver. This is because consideration was given to

If it is determined in step S3 that the slip amount s of the front wheels 60, 61 is smaller than 2 km/h, or if it is determined in step S4 that the slip amount change rate GS is smaller than 0.2 g. In this case, the process directly proceeds to step S6, and the TCL 58 outputs the maximum torque of the engine 11 as the target drive torque TOS in step S8, thereby causing the ECU 54 to set the duty rate of the torque control solenoid valves 46 and 51 to 0. As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

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

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 FS is reset in step S10, and the process proceeds to step S6. Transition.

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

Note that if the driver does not operate the manual switch for selecting slip control, the TCL 58 calculates the target drive torque TOS for slip control as described above, and then selects the engine when turning control is performed. 11 target drive torque is calculated.

[0075] When controlling the turning of the vehicle 68, the TCL5
8 calculates the target lateral acceleration GYO of the vehicle 68 from the steering shaft turning angle δH 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;
In other words, the target longitudinal acceleration GXO is the target lateral acceleration GYO
Set based on. And this target longitudinal acceleration GX
The target drive torque of the engine 11 corresponding to O is calculated.

By the way, although the lateral acceleration GY of the vehicle 68 can actually be calculated using the rear wheel speed difference |VRL-VRR|, the lateral acceleration GY acting on the vehicle 68 can be calculated using the steering shaft turning angle δH. Since the value of the lateral acceleration GY can be predicted, there is an advantage that quick control can be performed.

However, simply determining the target drive torque of the engine 11 based on the steering shaft turning angle δH and the vehicle speed V does not reflect the driver's intention at all, and may leave the driver dissatisfied with the maneuverability of the vehicle 68. There is a possibility that it will remain. For this reason, it is desirable to determine the required driving torque Td of the engine 11 desired by the driver from the amount of depression of the accelerator pedal 26, and to set the target driving torque of the engine 11 in consideration of this required driving torque Td. 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, if the target drive torque of the engine 11 is not changed depending on whether the road surface is a high μ road or a low μ road, for example, when driving on a low μ road, the engine 11 may be changed with the target drive torque for a high μ road.
If you drive a TCL58, there is a risk that the front wheels 60 and 61 may slip, making safe driving impossible.
It is desirable to calculate the target drive torque TOH for high-μ roads and the target drive torque TOL for low-μ roads, respectively.

As shown in FIGS. 12 and 13, which represent calculation blocks for turning control for high μ roads in consideration of the above knowledge, the TCL 58 calculates the vehicle speed V from the outputs of the pair of rear wheel rotation sensors 66 and 67. The front wheels 60,
The rudder angle δ of vehicle 61 is calculated using the formula (8) below, and at this time
The target lateral acceleration GYO of 8 is calculated from the following formula (9). δ=δH/ρH
…
(8) GYO=δ/{ω(A+1/
V2 )} (9) where ρH is the steering gear transmission ratio, ω is the wheelbase of the vehicle 68, and A is the stability factor of the vehicle.

As is well known, the stability factor A is a value determined by the configuration of the suspension system of the vehicle 68, the characteristics of the tires, etc. Specifically, the actual lateral acceleration GY generated in the vehicle 68 during a steady circular turn and the steering angle ratio δH /δHO of the steering shaft 69 at this time (lateral acceleration GY with reference to the neutral position δM of the steering shaft 69) For example, the slope of the tangent in a graph such as that shown in FIG. It is expressed as In other words, in a region where the lateral acceleration GY is small and the vehicle speed V is not very high, the stability factor A is almost a constant value (A = 0.002), but when the lateral acceleration GY exceeds 0.6 g, the stability factor A is almost constant (A=0.002). The stability factor A increases rapidly, and the vehicle 68 begins to exhibit an extremely strong tendency to understeering.

Based on the above, when based on FIG. 14, the stability factor A is set to 0.002 or less, and the target lateral acceleration GYO of the vehicle 68 calculated by equation (9) is 0. The target drive torque of the engine 11 is controlled so that it is less than .6g.

Once the target lateral acceleration GYO is calculated in this way, the target longitudinal acceleration G of the vehicle 68, which has been set in advance according to the magnitude of the target lateral acceleration GYO and the vehicle speed V, is calculated.
XO is determined from a map shown in FIG. 15 that is stored in advance in the TCL58, and engine
The reference drive torque TB of 1 is calculated using the following formula (10). TB = (GXO・Wb・r+TL
)/(ρm ・ρd) …(10) However, T
L is the road resistance which is determined as a function of the lateral acceleration GY of the vehicle 68.
) Torque, which is obtained from a map as shown in FIG. 16 in this embodiment.

Next, in order to determine the adoption ratio of the reference drive torque TB, the reference drive torque TB 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 NE detected by the crank angle sensor 55 and the accelerator opening θA detected by the accelerator opening sensor 59, the required driving torque Td desired by the driver is determined as shown in FIG. The corrected required driving torque is determined from the map, and then the corrected required driving torque corresponding to the weighting coefficient α is calculated by multiplying the required driving torque Td by (1-α). For example, if α is set to 0.6, the reference drive torque TB and the desired drive torque Td
The adoption ratio will be 6:4.

Therefore, the target driving torque TOH of the engine 11
is calculated using the following formula (11). TOH=α・TB +(1−α)・T
d...(11)

008
6] The vehicle 68 is provided with a manual switch (not shown) for the driver to select turning control for high μ roads.
When the driver operates this manual switch and selects turning control for high μ roads, the following operation of turning control for high μ roads is performed.

Target drive torque T for this high μ road turning control
Figures 18 and 19 depicting the control flow for determining OH
As shown in FIG. 2, the target drive torque TOH is calculated by detecting and calculating the various data described above in H1, but this operation is performed independently of the operation of the manual switch.

Next, at H2, it is determined whether the vehicle 68 is under turning control on a high μ road, that is, the high μ road turning control flag F
Determine whether CH is set. Initially, since high μ road turning control is not in progress, it is determined that the high μ road turning control flag FCH is in the reset state, and at H3, the target drive torque TOH is set to a preset threshold value, for example (Td −
2) Determine whether or not the following is true. That is, although the target drive torque TOH can be calculated even when the vehicle 68 is traveling straight, the value is usually much larger than the driver's requested drive torque Td. However, this required driving torque T
Since d generally becomes smaller when the vehicle 68 turns,
He is trying to set it as a starting condition of turning control when target drive torque TOH becomes below a threshold value (Td-2).

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

Target drive torque TOH at step H3
is less than the threshold (Td −2), TCL
58 determines whether the idle switch 57 is in the off state at H4.

If it is determined in step H4 that the idle switch 57 is off, that is, the accelerator pedal 26 is depressed by the driver, the high μ road turning control flag FCH is set in step H5. Next, in H6, it is determined whether the steering angle neutral position learned flag FH 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 FH is set, it is again determined in H7 whether or not the high μ road turning control flag FCH is set.

In the above procedure, in step H5, high μ
Since the road turning control flag FCH is set, H
In step 7, it is determined that the high μ road turning control flag FCH is set, and in H8, the previously calculated value, that is, H
The target drive torque TOH in step 1 is used as is.

On the other hand, if it is determined in step H6 that the steering angle neutral position learned flag FH is not set, the steering angle δ calculated by equation (8) is not reliable, so (11) The TCL58 does not use the target drive torque TOH calculated by the formula, but outputs the maximum torque of the engine 11 as the target drive torque TOH at H9, and thereby the ECU
54 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.

Further, if it is determined in step H3 that the target drive torque TOH is not below the threshold value (Td -2), the process moves from step H6 or H7 to step H9 without moving to turning control, and the TCL58 The maximum torque of the engine 11 is output as the target drive torque TOH, and as a result, the ECU 54 lowers the duty ratio of the torque control solenoid valves 46 and 51 to 0%, and as a result, the engine 11 is controlled by the amount of depression of the accelerator pedal 26 by the driver. Generates driving torque according to the

Similarly, 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 TC
L58 outputs the maximum torque of the engine 11 as the target drive torque TOH, and as a result, the ECU 54 lowers the duty ratio of the torque control solenoid valves 46, 51 to the 0% side. It generates a driving torque according to the amount of depression and does not shift to turning control.

If it is determined in step H2 that the high μ road turning control flag FCH is set,
At H10, it is determined whether the difference ΔT between the target drive torque TOH calculated this time and the target drive torque TOH (n-1) calculated last time is larger than a preset allowable increase/decrease amount TK. This allowable increase/decrease amount TK is a torque change amount that does not cause the occupants to feel acceleration/deceleration shock of the vehicle 68.
For example, the target longitudinal acceleration GXO of the vehicle 68 is 0.1 g per second.
If you want to suppress TK = (0.1・Wb・r・Δt)/(ρm・ρ
d).

The target drive torque TOH calculated this time in step H10 and the target drive torque TOH calculated last time
The difference ΔT from H(n-1) is the preset increase/decrease tolerance T
If it is determined that the difference ΔT between the target drive torque TOH and the previously calculated target drive torque TOH (n-1) is not larger than K, then in H11 the difference ΔT between the target drive torque TOH and the previously calculated target drive torque TOH (n-1) is determined to be a negative increase/decrease allowable amount TK.
Determine whether it is larger than .

At step H11, the current target drive torque TOH and the previously calculated target drive torque TOH (n-1
) is determined to be larger than the negative increase/decrease allowable amount TK, the absolute value of the difference between the target drive torque TOH calculated this time and the target drive torque TOH (n-1) calculated last time increases or decreases |ΔT| Since it is smaller than the allowable amount TK, the current calculated target drive torque TOH is used as it is as the calculated value in step H8.

[0100] Also, the target drive torque TOH calculated this time in step H11 and the target drive torque TOH calculated last time
If it is determined that the difference ΔT from H(n-1) is not larger than the negative increase/decrease tolerance TK, the current target drive torque TOH is corrected in H12 using the formula below, and this is used as the calculated value in step H8. Adopted as. TOH=TOH(n-1) -TK In other words, the target drive torque TOH(n-1) calculated last time
The amount of decrease in engine 1 is regulated by the allowable increase/decrease amount TK.
This reduces the deceleration shock that accompanies the reduction in driving torque in step 1.

On the other hand, if it is determined in step H10 that the difference ΔT between the target drive torque TOH calculated this time and the target drive torque TOH (n-1) calculated last time is greater than or equal to the allowable increase/decrease amount TK, then H13 The current target drive torque TOH is corrected using the formula below, and this is adopted as the calculated value in step H8. TOH=TOH(n-1) +TK In other words, in the case of an increase in drive torque, the target drive torque TOH calculated this time is the same as in the case of a decrease in drive torque described above.
If the difference ΔT between the previously calculated target drive torque TOH (n-1) and the previously calculated target drive torque TOH (n-1) exceeds the increase/decrease tolerance TK, the amount of increase relative to the previously calculated target drive torque TOH (n-1) is regulated by the increase/decrease tolerance TK. Therefore, the acceleration shock caused by the increase in the driving torque of the engine 11 is reduced.

In this way, when the increase/decrease of the target drive torque TOH is regulated, the steering shaft turning angle δH, the target longitudinal acceleration GXO, the target drive torque TOH, and the actual longitudinal acceleration G
As shown in FIG. 20, where the state of change with respect to G It appears that it has been resolved.

When the target drive torque TOH is set as described above, the TCL 58 determines in H14 whether or not the target drive torque TOH is larger than the driver's requested drive torque Td.

Here, if the high μ road turning control flag FCH is set, the target drive torque TOH is not larger than the driver's requested drive torque Td, so H15
It is determined 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, the turning control is required, so the process moves to step H6.

Furthermore, if it is determined in step H14 that the target drive torque TOH is larger than the driver's requested drive torque Td, this means that the vehicle 68 has finished turning, so the TCL58 is set in step H16. Reset the high μ road turning control flag FCH. Similarly, if 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 FCH is set. Reset.

[0107] In this H16, the high μ road turning control flag F
When CH is reset, TCL58 outputs the maximum torque of engine 11 as target drive torque TOH at H9,
This causes the ECU 54 to control the torque control solenoid valves 46, 51.
As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

In this embodiment, the target drive torque TOH of the engine 11 is calculated from the target lateral acceleration GYO of the vehicle 68, and the target drive torque TOH and a preset threshold value (Td
-2), the target drive torque TOH is the threshold value (T
d-2) It is determined that the turning control is to be started when the target lateral acceleration GYO of the vehicle 68 is lower than or equal to d-2). Of course, it is also possible to determine that the turning control is to be started when the angle becomes equal to or greater than the reference value of 0.6 g.

[0109] Target drive torque T for this high μ road turning control
After calculating OH, the TCL 58 calculates the target drive torque TOL for low μ road turning control as follows.

By the way, on a low μ road, the actual lateral acceleration GY
Since the target lateral acceleration GYO has a larger value than the target lateral acceleration GYO, it is determined whether the target lateral acceleration GYO is larger than a preset threshold value, and if the target lateral acceleration GYO is larger than this threshold value, the vehicle 68 It is sufficient to determine that the vehicle is traveling on a low μ road and perform turning control as necessary.

As shown in FIGS. 21 and 22, which represent calculation blocks for turning control for low μ roads, the steering shaft turning angle δH
The target lateral acceleration GYO is calculated from the above equation (9) from the vehicle speed V and the stability factor A at this time.
For example, 0.005 is adopted.

Next, the target longitudinal acceleration GXO is determined from the target lateral acceleration GYO and the vehicle speed V. In this embodiment, the target longitudinal acceleration GXO is read from a map as shown in FIG. This map shows the target longitudinal acceleration GXO, which allows the vehicle 68 to travel safely, in relation to the vehicle speed V according to the magnitude of the target lateral acceleration GYO, and is set based on test driving results, etc. .

Then, based on this target longitudinal acceleration GXO, the reference drive torque TB is calculated by the above equation (10) or determined from a map to determine the adoption ratio of this reference drive torque TB. In this case, the weighting coefficient α is larger than the coefficient α for high μ roads, for example α=0.8
This is to reduce the ratio of reflection to the driver's request on a low μ road, and to enable safe and reliable turning on a highly dangerous low μ road.

On the other hand, as the driver's required drive torque Td, the one calculated during calculation work for high μ roads is used as is, and therefore the target drive torque TOL is calculated by taking the required drive torque Td into consideration in the standard drive torque TB. is mentioned above (
It is calculated using the following equation (12), which is similar to equation 11). TOL=α・TB +(1−α)・T
d...(12)

011
5] The vehicle 68 is provided with a manual switch (not shown) for the driver to select turning control for low μ roads.
When the driver operates this manual switch and selects turning control for low μ roads, the following operation of turning control for low μ roads is performed.

[0116] Target drive torque T for this low μ road turning control
FIG. 24 and FIG. 2 showing the flow of control for determining OL
As shown in 5, the target drive torque TOL is calculated at L1 by detecting and calculating various data as described above, but this operation is performed regardless of the operation of the manual switch.

Next, at L2, it is determined whether the vehicle 68 is under low μ road turning control, that is, the low μ road turning control flag F
Determine whether CL is set. At first, since low μ road turning control is not in progress, it is determined that the low μ road turning control flag FCL is in the reset state, and at L3, the rear wheel
Actual lateral acceleration GY calculated from the rotation difference between 4 and 65
By adding 0.05 g to It is determined whether the 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. Note that the actual lateral acceleration GY generated in the vehicle 68 can be calculated using the following formula (1
3) is calculated as follows. GY = (|VRL−VRR|・V)
/(3.62 · b · g) ... (13) However, b is the tread of the rear wheels 64 and 65.

[0118] In step L3, the target lateral acceleration GY
If it is determined that O is larger than the threshold value (GY +0.05g), that is, the vehicle 68 is turning on a low μ road, the TCL
58 is a low μ (not shown) built into TCL58 at L4.
The road timer 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 L
6 and subsequent steps, repeating the above (9) every 15 milliseconds.
The target lateral acceleration GYO according to the formula (13) and the actual lateral acceleration GY according to the formula (13) are calculated and the determination operation of L3 is repeated.

[0119] In other words, 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 L6 and L7, and the TCL58 sets the maximum torque of the engine 11 as the target drive torque TOL. As a result, the ECU 54 lowers 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.

[0120] The target lateral acceleration GYO is the threshold value (GY +0.
05g) If the condition greater than 0.5 seconds does not continue, T
CL58 determines that the vehicle 68 is not traveling on a low μ road, clears the low μ road timer count at L9, and returns to L6.
-Proceed to step L8.

[0121] The target lateral acceleration GYO is the threshold value (GY +0.
05g) If the state continues for 0.5 seconds, L10
Determine whether or not the idle switch 57 is in the off state,
If it is determined that the idle switch 57 is in the on state, that is, the accelerator pedal 26 is not depressed by the driver, the low μ road timer is counted at L9 without proceeding to turning control for low μ roads. Cleared, the process moves to steps L6 to L8, and the TCL 58 outputs the maximum torque of the engine 11 as the target drive torque TOL.
4 sets the duty rate of the torque control solenoid valves 46 and 51 to 0.
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 it is determined in step L10 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 L11. Next, L
In step 6, it is determined whether the steering angle neutral position learned flag FH is set, that is, the reliability of the steering angle δ detected by the steering angle sensor 70 is determined.

If it is determined in step L6 that the steering angle neutral position learned flag FH 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 L11, the previously calculated value, that is, the target drive torque TOL in step L1, is adopted as is in step L12. .

If it is determined in step L6 that the steering angle neutral position learned flag FH is not set, the steering angle δ is unreliable, so the process moves to step L8, and the process moves to step L1.
The target drive torque TOL of equation (12) previously calculated by
The TCL 58 outputs the maximum torque of the engine 11 as the target drive torque TOL, and thereby the ECU 54
sets the duty rate of the torque control solenoid valves 46 and 51 to 0%.
As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

On the other hand, if it is determined in step L2 that the low μ road turning control flag FCL is set, the process moves to step L13.

[0126] In steps L13 to L16, high μ
As in the case of road turning control, the target drive torque TOL calculated this time and the target drive torque TOL (n-
1) Determine whether the difference ΔT is larger than the allowable increase/decrease amount TK, and in either case, this is
If it is within K, the target drive torque TOL calculated this time
is directly adopted as the calculated value in step L12,
If ΔT exceeds the allowable increase/decrease amount TK, the target drive torque TOL is regulated by the allowable increase/decrease amount TK.

[0127] In other words, when decreasing the target drive torque TOL, the current target drive torque TOL is corrected to TOL=TOL(n-1) -TK in L15, and this is used as the calculated value in step L12. adopt. Conversely, when increasing the target drive torque TOL, the current target drive torque TOL is changed to TOL in L16.
=TOL(n-1) +TK, and this is adopted as the calculated value in step L12.

When the target drive torque TOL is set as described above, the TCL 58 determines in L17 whether or not the target drive torque TOL is larger than the driver's requested drive torque Td.

Here, if the low μ road turning control flag FCL is set, the target drive torque TOL is not larger than the required drive torque Td, so the process moves to step L9 and the low μ road timer counts. Clear L6
, L7, where it is determined that the steering angle neutral position learned flag FH is set, and furthermore that the low μ road turning control flag FCL is set, L1 or L15. Or, the calculated value adopted in step L16 is the target drive torque TOL for low μ road turning control.
selected as.

Furthermore, even if it is determined in step L17 that the target drive torque TOL is larger than the driver's requested drive torque Td, the steering shaft turning angle δ is determined in the next step L18.
If it is determined that H 2 is not less than, for example, 20 degrees, the vehicle 68 is currently turning, so turning control is continued as is.

[0131] If it is determined in step L17 that the target drive torque TOL is larger than the driver's requested drive torque Td, and if it is determined in L18 that the steering shaft turning angle δH is less than 20 degrees, for example, This means that the vehicle 68 has finished turning, so TCL58 is L19.
The low μ road turning control flag FCL is reset at .

When the low μ road turning control flag FCL is reset in step L19, there is no need to count the low μ road timer, so the count of the low μ road timer is cleared, and L6, The process moves to step L7, but since it is determined in step L7 that the low μ road turning control flag FCL is in the reset state, the process moves to step L8, and the TCL58 sets the maximum torque of the engine 11 as the target drive torque TOL. As a result of outputting torque, the ECU 54 lowers the duty ratio of the torque control solenoid valves 46 and 51 to the 0% side, and as a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver.

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 calculated using the above equation (10). Standard drive torque TB
You should adopt. Furthermore, even when the driver's required drive torque Td is taken into account as in this embodiment, the weighting coefficient α
Instead of setting it to a fixed value, the value of the coefficient α is gradually decreased as time passes after the start of control as shown in FIG. 26, or it is gradually decreased according to the vehicle speed as shown in FIG. The adoption ratio of the required drive torque Td may be gradually increased. Similarly, as shown in FIG. 28, the value of the coefficient α is kept constant for a while after the start of control, and then it is gradually decreased after a predetermined period of time has elapsed, or the coefficient It is also possible to increase the value of α so that the vehicle 68 can be driven safely, especially on turning paths where the radius of curvature gradually becomes smaller.

[0134] Furthermore, in the arithmetic processing method described above, the engine 1
In order to prevent acceleration/deceleration shock due to rapid fluctuations in the drive torque in step 1, when calculating the target drive torques TOH and TOL, the target drive torque T is
Although OH and TOL are restricted, this restriction may also be applied to the target longitudinal acceleration GXO. When the allowable increase/decrease amount in this case is GK, the calculation process of the target longitudinal acceleration GXO(n) at n times is shown below.

[0135] Note that the sampling time of the main timer is set to 1.
5 milliseconds and the change in target longitudinal acceleration GXO is 0.5 milliseconds per second.
If you want to keep it to 1g, GK = 0.1·Δt.

[0136] Target drive torque T for this low μ road turning control
After calculating OL, the TCL 58 selects the optimal final target drive torque TO from these three target drive torques TOS, TOH, and TOL, and outputs it to the ECU 54. 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 TOS for slip control is low μ.
Since it is always smaller than the target drive torque TOL for road turning control, the final target drive torque TO may be selected in the order of slip control, low μ road turning control, and high μ road turning control.

As shown in FIG. 29, which shows the flow of this process, the three target drive torques TOS, T described above in M11 are
After calculating OH and TOL, it is determined in M12 whether the slip control flag FS is set.

If it is determined in step M12 that the slip control flag FS is set, T
The CL58 selects the target drive torque TOS for slip control as the final target drive torque TO using M13, and outputs this to the ECU54.

[0139] The ECU 54 stores a map for determining the throttle opening θT using the engine speed NE and the driving torque of the engine 11 as parameters.
Using this map, the ECU 54 reads out the target throttle opening θTO corresponding to the current engine speed NE and the target drive torque TOS. Next, the ECU 54 uses this target throttle opening θTO and the throttle opening sensor 5.
The deviation from the actual throttle opening θT output from 6 is determined, and the duty ratio of the pair of torque control solenoid valves 46, 51 is set to a value commensurate with the deviation. Current is applied to the solenoids of the plungers 47 and 52, and the actuator 36 is operated to control the actual throttle opening θT to fall to the target value θTO.

[0140] If it is determined in step M12 that the slip control flag FS is not set,
At M15, it is determined whether the low μ road turning control flag FCL is set.

[0141] If it is determined in step M15 that the low μ road turning control flag FCL is set,
The target drive torque TOL for low μ road turning control is selected as the final target drive torque TO in M16, and the process moves to step M14.

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

If it is determined in step M17 that the high μ road turning control flag FCH is set, the target drive torque TOH for high μ road turning control is set in M18 as the final target drive torque TO. and select M1
Move on to step 4.

On the other hand, if it is determined in step M17 that the high μ road turning control flag FCH is not set, the TCL 58 outputs the maximum torque of the engine 11 as the final target drive torque TO, and thereby the ECU 54
sets the duty rate of the torque control solenoid valves 46 and 51 to 0%.
As a result, the engine 11 generates a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver. In this case, in this embodiment, a pair of torque control solenoid valves 4
6,51 duty rate is not set to 0% unconditionally, EC
U54 compares the actual accelerator opening θA and the maximum throttle opening regulation value, and if the accelerator opening θA exceeds the maximum throttle opening regulation value, adjusts the accelerator opening θA so that it becomes the maximum throttle opening regulation value. Next, the duty ratio of the pair of torque control solenoid valves 46, 51 is determined, and the plungers 47, 52 are driven. This maximum throttle opening regulation value is a function of the engine speed NE, and is set at or near a fully closed state above a certain value (for example, 2000 rpm), but in the low speed range below this value, the engine speed The opening is set to gradually decrease to several tens of percent as NE decreases.

The reason why the throttle opening degree θT is regulated in this manner is to improve the responsiveness of control when the TCL 58 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 tends to make the bore diameter (passage cross-sectional area) of the throttle body 16 extremely large in order to improve the acceleration performance and maximum output of the vehicle 68, and the engine 11 tends to be in a low rotation range. In some cases, the intake air amount becomes saturated when the throttle opening degree θT is about several tens of percent. Therefore, rather than setting the throttle opening θT 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, the target throttle when a drive torque reduction command is issued. This is because the deviation between the opening degree θTO and the actual throttle opening degree θT is reduced, and the throttle opening degree θTO can be quickly lowered to the target throttle opening degree θTO.

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

On the contrary, a target drive torque TOC for one type of turning control is calculated, and when slip control is being performed, this target drive torque TOS for slip control is more general than the target drive torque TOC for turning control. Since the target driving torque TOS for slip control is always small, it is naturally possible to select the target driving torque TOS for slip control in preference to the target driving torque TOC for turning control.

As shown in FIG. 30, which shows the processing flow of another embodiment of the present invention, at M21, the target drive torque TOS for slip control and the target drive torque TOC for turning control are set as described above. After calculating in the same manner as above, it is determined in M22 whether or not the slip control flag FS is set.

If it is determined in step M22 that the slip control flag FS is set, the target drive torque TOS for slip control is selected as the final target drive torque TO in M23. And M24
At , the ECU 54 reads out the target throttle opening θTO corresponding to the current engine speed NE and this target drive torque TOS from the map stored in the ECU 54, and reads out the target throttle opening θTO and the throttle opening sensor 56.
The deviation from the actual throttle opening θT outputted from is determined, and the duty ratio of the pair of torque control solenoid valves 46, 51 is set to a value commensurate with the deviation, and the plunger of each torque control solenoid valve 46, 51 is set. Current is applied to the solenoids 47 and 52, and the actuator 36 is operated to control the actual throttle opening θT to fall to the target value θTO.

[0150] If it is determined in step M22 that the slip control flag FS is not set,
At M25, it is determined whether the turning control flag FC is set.

If it is determined in step M25 that the turning control flag FC is set, the target drive torque TOC for turning control is selected as the final target drive torque TO in M26, and the process proceeds to step M24. Transition.

On the other hand, if it is determined in step M25 that the turning control flag FC is not set, the TCL 58 sets the final target drive torque TO to the engine 1.
As a result, the ECU 54 lowers the duty ratio of the torque control solenoid valves 46 and 51 to 0%, and the engine 11 outputs a driving torque corresponding to the amount of depression of the accelerator pedal 26 by the driver. Occur.

[0153]

[Effects of the Invention] According to the vehicle output control device of the present invention,
Calculates the magnitude of lateral acceleration that occurs when the vehicle turns based on detection signals from a steering angle sensor and a vehicle speed sensor,
Since the engine drive torque is reduced according to the magnitude of this lateral acceleration, the lateral acceleration can be detected more quickly than the conventional method, which detects the magnitude of lateral acceleration based on the yaw rate etc. that actually occurs in the vehicle. The size of 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 shocks and the like during gear changes in an automatic transmission. Further, according to this output control device, since the increase/decrease of torque is regulated, it is possible to reduce or eliminate acceleration/deceleration shock during turning control.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of an engine control system that can realize a vehicle output control device according to the present invention.

FIG. 2 is a conceptual diagram.

FIG. 3 is a sectional view showing a throttle valve drive mechanism.

FIG. 4 is a flowchart showing the overall flow of control.

FIG. 5 is a flowchart showing the flow of neutral position learning correction control of the steering shaft.

FIG. 6 is a flowchart showing the flow of neutral position learning correction control of the steering shaft.

FIG. 7 is a graph showing an example of a state of correction of a learned value when learning and correcting the neutral position of the steering shaft.

FIG. 8 is a graph showing the relationship between the coefficient of friction between the tire and the road surface and the slip rate of the tire.

FIG. 9 is a map showing the relationship between vehicle speed and running resistance.

FIG. 10 is a map showing the relationship between corrected longitudinal acceleration and speed correction amount.

FIG. 11 is a flowchart showing the flow of slip control.

FIG. 12 is a block diagram showing a procedure for calculating a target drive torque for a high μ road.

FIG. 13 is a block diagram showing a procedure for calculating a target drive torque for a high μ road.

FIG. 14 is a graph showing the relationship between lateral acceleration and steering angle ratio for explaining the stability factor.

FIG. 15 is a map showing the relationship between target lateral acceleration, target longitudinal acceleration, and vehicle speed.

FIG. 16 is a map showing the relationship between lateral acceleration and load torque.

FIG. 17 is a map showing the relationship between engine speed, accelerator opening, and required drive torque.

FIG. 18 is a flowchart showing the flow of turning control for high μ roads.

FIG. 19 is a flowchart showing the flow of turning control for high μ roads.

FIG. 20 is a graph showing the relationship between the steering shaft turning angle, target drive torque, and longitudinal acceleration.

FIG. 21 is a block diagram showing a procedure for calculating a target drive torque for a low μ road.

FIG. 22 is a block diagram showing a procedure for calculating a target drive torque for a low μ road.

FIG. 23 is a map showing the relationship between target lateral acceleration, target longitudinal acceleration, and vehicle speed.

FIG. 24 is a flowchart showing the flow of turning control for low μ roads.

FIG. 25 is a flowchart showing the flow of turning control for low μ roads.

FIG. 26 is a graph showing the relationship between time after the start of control and weighting coefficients.

FIG. 27 is a graph showing the relationship between vehicle speed and weighting coefficient.

FIG. 28 is a graph showing the relationship between vehicle speed and weighting coefficient.

FIG. 29 is a flowchart illustrating an example of a final target torque selection operation.

FIG. 30 is a flowchart illustrating another example of the final target torque selection operation.

[Explanation of symbols]

11 is an engine, 12 is a combustion chamber, 13 is an intake pipe, 14 is an intake passage, 15 is a throttle valve, 17 is a throttle shaft, 18
is an accelerator lever, 19 is a throttle lever, 26 is an accelerator pedal, 27 is a cable, 29 is a pawl, 30 is a stopper, 36 is an actuator, 38 is a control rod, 42 is a connecting pipe, 43 is a vacuum tank, 44 is a non-return check valve,
45, 50 are piping, 46, 51 are torque control solenoid valves,
54 is ECU, 55 is crank angle sensor, 56 is throttle opening sensor, 57 is idle switch, 58 is TC
L, 59 is the accelerator opening sensor, 60, 61 are the front wheels, 6
2, 63 are front wheel rotation sensors, 64, 65 are rear wheels, 66,
67 is a rear wheel rotation sensor, 68 is a vehicle, 69 is a steering shaft, 7
0 is a steering angle sensor, and 71 is a communication cable. Also, A
is the stability factor, FH is the steering angle neutral position learned flag, FS is the slip control flag, and FCH is the high μ
Road turning control flag, FCL is low μ road turning control flag, FC is turning control flag, GXO is target longitudinal acceleration, GX is longitudinal acceleration, GY is lateral acceleration, GYO
is the target lateral acceleration, g is the gravitational acceleration, TOS is the target drive torque for slip control, TOH is the target drive torque for high μ roads, TOL is the target drive torque for low μ roads, TOC is the target drive torque for turning control, and TO is Final target drive torque, TB
is the standard drive torque, Td is the required drive torque, V is the vehicle speed, s is the slip amount, θA is the accelerator opening, θT is the throttle opening, θTO is the target throttle opening, δ is the front wheel steering angle, δH is the steering axis The turning angle, δM, is the neutral position of the steering shaft.

Claims (2)

[Claims] 1. Torque control means for reducing the driving torque of the engine independently of the operation by the driver, a steering angle sensor for detecting the turning angle of the steering shaft, a vehicle speed sensor for detecting the speed of the vehicle, and a steering system comprising: The lateral acceleration of the vehicle is calculated based on the detection signals from the angle sensor and the vehicle speed sensor, and the target driving torque of the engine is calculated according to the magnitude of this lateral acceleration, and the target driving torque and the previously calculated target are calculated. a torque calculation unit that regulates the increase or decrease of the current target drive torque by comparing it with the drive torque; and an electronic control unit that controls the operation of the torque control means so that the drive torque of the engine becomes the target drive torque. A vehicle output control device comprising: 2. The torque calculation unit according to claim 1, wherein instead of regulating the increase/decrease in the target drive torque, the torque calculation unit regulates the increase/decrease in the target longitudinal acceleration obtained before calculating the target drive torque. vehicle output control device.