JP2536309B2 - Vehicle output control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle output control device for correcting cornering drag according to a friction coefficient of a road surface when reducing a driving torque of an engine.

[0002]

2. Description of the Related Art When a vehicle is running, the condition of the road surface changes abruptly, or when the vehicle runs on a slippery road surface having a low friction coefficient, for example, a snow road or an icy road, the drive wheels spin idle. There is. In such a case, it is very difficult for a 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 idle.

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

In such a case, in order to properly lower the output of the engine and safely drive the vehicle at a turning radius corresponding to the turning circuit, it is necessary to check the exit of the turning circuit, or if the exit of the turning circuit cannot be confirmed. When the radius of curvature is gradually reduced, extremely advanced driving technology is required. In a general vehicle having a so-called understeering tendency, it is necessary to gradually increase the steering amount with an increase in the lateral acceleration applied to the vehicle. However, when the lateral acceleration exceeds a certain value specific to each vehicle, the steering becomes As described above, the fuel cell has such characteristics that it becomes difficult or impossible to make a safe turning operation as described above. It is well known that this tendency becomes remarkable especially in a front engine front-wheel drive type vehicle with a strong tendency to understeer.

From the above, when the idling state of the drive wheels is detected and the idling of the drive wheels occurs, the output of the engine is forcibly reduced regardless of the depression amount of the accelerator pedal by the driver. Or to detect the lateral acceleration of the vehicle and forcibly reduce the output of the engine before the turning limit at which the vehicle becomes difficult or unable to turn, regardless of the accelerator pedal depression amount by the driver. In order to enable the driver to select between traveling using this output control device and normal traveling in which the output of the engine is controlled according to the amount of depression of the accelerator pedal, as required. What has been done has been announced.

Among those related to the output control of the vehicle based on this point of view, the conventionally known one detects, for example, the rotational speeds of the driving wheels and the driven wheels, and detects the driving wheels and the driven wheels. The difference in rotation speed is regarded as the slip amount of the drive wheel,
The target drive torque of the engine is set based on the slip amount and the running state of the vehicle or based on the yawing amount, and the opening degree of the throttle valve and the ignition timing are set so that the drive torque of the engine becomes the target drive torque. Etc. are controlled.

[0007]

However, conventionally, the cornering drag correction is performed assuming a constant road surface μ. Since the road surface μ changes from moment to moment, the present invention provides a vehicle output control device capable of performing cornering drag correction according to the friction coefficient of the road surface when reducing the drive torque of the engine in turning control and slip control. The purpose is to provide.

[0008]

A vehicle output control device for turning control according to the present invention detects a turning angle of a steering shaft and a torque control means for reducing a driving torque of an engine independently of a driver's operation. Steering angle sensor, a vehicle speed sensor for detecting the speed of the vehicle, a means for estimating a road surface friction coefficient, a means for calculating a cornering drag correction torque according to the estimated road surface friction coefficient, the steering angle sensor and the vehicle speed. The lateral acceleration of the vehicle is calculated based on the detection signal from the sensor, and the basic driving torque according to the magnitude of the lateral acceleration is calculated, and the target driving is calculated from the sum of the basic driving torque and the cornering drag correction torque. A torque calculation unit for calculating torque and an electronic control unit for controlling the torque control means so that the output torque of the engine becomes a target drive torque. It is characterized in that comprises a. Further, the vehicle output control device for slip control according to the present invention sets the torque reducing means for reducing the drive torque of the engine independently of the operation by the driver, and sets the drive torque as the reference of the engine based on the traveling speed of the vehicle. Reference drive torque setting means, means for estimating the friction coefficient of the road surface, means for calculating the cornering drag correction torque according to the estimated road surface friction coefficient, and target drive wheel speed setting for setting the target peripheral speed of the drive wheels. Means, means for detecting the actual drive wheel speed, correction torque calculation means for calculating a correction torque from the deviation between the actual drive wheel speed and the target drive wheel speed, and the correction torque for the set reference torque and cornering drag. Target drive torque setting means for setting a target drive torque of the engine by subtracting from the sum with the correction torque, and the target drive for which the drive torque of the engine is set as described above. It is characterized in that it comprises a torque control unit for controlling the operation of the torque reducing means such that the torque.

[0009]

In either of the turning control and the slip control, the cornering drag correction torque is obtained according to the estimated value of the road surface μ. Therefore, the target drive torque on the low μ road is not too large, and conversely, the target drive torque on the high μ road is not too small.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 showing the concept of an embodiment in which a vehicle output control device according to the present invention is applied to a front-wheel drive type vehicle incorporating an automatic transmission of four forward gears and one reverse gear and a schematic structure of the vehicle. As shown in FIG. 2, which is shown in FIG.
Is connected to the input shaft 14 of the hydraulic automatic transmission 13. The hydraulic automatic transmission 13 includes an electronic control unit (hereinafter, referred to as an ECU) 15 that controls the operation state of the engine 11 in accordance with the position of a select lever (not shown) selected by the driver and the operation state of the vehicle. A predetermined gear position is automatically selected via the hydraulic control device 16 based on a command from the controller. This hydraulic automatic transmission 1
For the specific configuration, operation, and the like of No. 3, see, for example,
As already known in Japanese Patent Application Laid-Open No. 54270/1986 and Japanese Patent Application Laid-Open No. 61-31749, the engagement of a plurality of friction engagement elements constituting a part of the hydraulic automatic transmission 13 in the hydraulic control device 16 is described. A pair of shift control solenoid valves (not shown) for performing the operation and the opening operation are incorporated, and the on / off operation of energization of these shift control solenoid valves is controlled by the ECU 15 to provide four forward stages and one reverse stage. In this case, the shift operation to any one of the speed stages is smoothly achieved.

In this embodiment, in order to reduce the steering force of the driver, a power steering device is incorporated in the steering mechanism, and the concept of this power steering device is shown in FIG.
As shown in FIG. 5, the pair of left and right front wheels 64, 65 has a rack and pinion mechanism (not shown) connected to the steering handle 85,
A power steering device 92 including a power actuator 91 connected to the rack and pinion mechanism is connected via a tie rod 93. A hydraulic pump 95 is connected to the power actuator 91 via a steering valve 94 that switches the flow of pressure oil to the power actuator 91 in accordance with the operation of the steering handle 85. Further, the hydraulic pump 95 driven by the engine 11 and the power actuator 91 are
A reservoir tank 96 for storing pressure oil is connected.

Therefore, when the steering wheel 85 is turned by the driver, the flow of pressure oil from the hydraulic pump 95 to the power actuator 91 is switched via the steering valve 94, which corresponds to the steering direction of the steering wheel 85. As a result of the steering force being transmitted to the rack and pinion mechanism via the power actuator 91, the front wheels 64, 6 are lightly steered.
5 is steered.

In the middle of the intake pipe 18 connected to the combustion chamber 17 of the engine 11, the opening degree of the intake passage 19 formed by the intake pipe 18 is changed to change the intake air amount supplied into the combustion chamber 17. A throttle body 21 incorporating a throttle valve 20 for adjusting the is inserted. As shown in FIG. 1 and FIG. 3 showing an enlarged cross-sectional structure of the cylindrical throttle body 21, both ends of a throttle shaft 22 integrally fixed with a throttle valve 20 are rotatably attached to the throttle body 21. It is supported. An accelerator lever 23 and a throttle lever 24 are coaxially fitted to one end of the throttle shaft 22 protruding into the intake passage 19.

The throttle shaft 22 and the accelerator lever 2
Bush 26 and spacer 27
Is interposed, whereby the accelerator lever 23 is rotatable with respect to the throttle shaft 22. Further, a washer 28 and a nut 29 attached to one end side of the throttle shaft 22 allow the throttle lever 22 to be released from the accelerator lever 23.
It prevents from slipping out. An accelerator pedal 31 operated by a driver is connected to a cable receiver 30 integral with the accelerator lever 23 via a cable 32. The accelerator lever 23 is connected to the throttle shaft in accordance with the depression amount of the accelerator pedal 31. 22.

On the other hand, the throttle lever 24 is fixed integrally with the throttle shaft 22. Therefore, by operating the throttle lever 24, the throttle valve 2
0 rotates together with the throttle shaft 22. A collar 33 is fitted coaxially and integrally with the cylinder portion 25 of the accelerator lever 23, and is engaged with a claw portion 34 formed on a part of the collar 33 at the tip of the throttle lever 24. A stopper 35 is formed. The pawl portion 34 and the stopper 35 are engaged with each other when the throttle lever 24 is turned in a direction in which the throttle valve 20 opens or the accelerator lever 23 is turned in a direction in which the throttle valve 20 closes. Is set in a proper positional relationship.

Between the throttle body 21 and the throttle lever 24, a stopper 35 of the throttle lever 24 and a claw portion 3 of a collar 33 integral with the accelerator lever 23 are provided.
4, a torsion coil spring 36 that urges the throttle valve 20 in the opening direction is coaxial with the throttle shaft 22 via a pair of cylindrical spring receivers 37 and 38 fitted to the throttle shaft 22. It has been installed. or,
Also between the stopper pin 39 protruding from the throttle body 21 and the accelerator lever 23, the claw portion 34 of the collar 33 is pressed against the stopper 35 of the throttle lever 24 to urge the throttle valve 20 in the closing direction, and the accelerator pedal 31 A torsion coil spring 40 for giving a sense of detent to the cylinder portion 25 of the accelerator lever 23 via the collar 33 is mounted coaxially with the throttle shaft 22.

At the tip of the throttle lever 24,
The distal end of a control rod 43 whose base end is fixed to the diaphragm 42 of the actuator 41 is connected. A compression coil spring 45 for pressing the stopper 35 of the throttle lever 24 together with the torsion coil spring 36 against the claw portion 34 of the collar 33 to urge the throttle valve 20 in the opening direction is provided in a pressure chamber 44 formed in the actuator 41. Is incorporated. Then, the spring force of the torsion coil spring 40 is set to be larger than the sum of the spring forces of these two springs 36 and 45, whereby the accelerator pedal 31
The throttle valve 20 is not opened unless the operator steps on the throttle valve.

A surge tank 46 connected to the downstream side of the throttle body 21 and forming a part of the intake passage 19.
A vacuum tank 48 communicates with the vacuum tank 48 via a connection pipe 47.
A check valve 49 that allows only the movement of air from the vacuum tank 48 to the surge tank 46 is interposed between the check valve 49 and the valve 7. Thus, the pressure in the vacuum tank 48 is set to a negative pressure substantially equal to the lowest pressure in the surge tank 46.

The inside of the vacuum tank 48 and the pressure chamber 44 of the actuator 41 are in communication with each other through a pipe 50, and in the middle of the pipe 50, there is a closed type non-energization type first torque control unit. A solenoid valve 51 is provided. That is, the pipe 50 is connected to the torque control solenoid valve 51.
A spring 54 for urging the plunger 52 against the valve seat 53 so as to close the valve is incorporated.

A pipe 55 between the first torque control solenoid valve 51 and the actuator 41 is connected to the intake passage 19 upstream of the throttle valve 20.
Is connected. A non-energized second torque control solenoid valve 56 is provided in the middle of the pipe 55. That is, the spring 5 for urging the plunger 57 to open the pipe 55 is provided to the torque control solenoid valve 56.
8 is incorporated.

The two torque control solenoid valves 51, 56
Are connected to the ECU 15, respectively.
Based on the command from 5, the torque control solenoid valves 51, 56
The ON / OFF of the energization is controlled by duty, and in this embodiment, the torque reducing means of the present invention is constituted by them as a whole.

For example, when the duty ratio of the torque control solenoid valves 51, 56 is 0%, the pressure chamber 44 of the actuator 41 has the intake passage 19 upstream of the throttle valve 20.
Atmospheric pressure which is almost equal to the pressure inside the throttle valve 20
Corresponds one-to-one to the depression amount of the accelerator pedal 31. Conversely, when the duty ratios of the torque control solenoid valves 51 and 56 are 100%, the pressure chamber 44 of the actuator 41 has a negative pressure substantially equal to the pressure in the vacuum tank 48, and the control rod 43 is inclined leftward in FIG. As a result, the throttle valve 20 is closed irrespective of the depression amount of the accelerator pedal 31, 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 51 and 56, the opening degree of the throttle valve 20 can be changed irrespective of the depression amount of the accelerator pedal 31, and the drive torque of the engine 11 can be adjusted arbitrarily.

Further, in this embodiment, the opening of the throttle valve 20 is controlled simultaneously by the accelerator pedal 31 and the actuator 41. However, two throttle valves are arranged in series in the intake passage 19 and one throttle It is also possible to connect the valve only to the accelerator pedal 31 and the other throttle valve only to the actuator 41 to control these two throttle valves independently.

On the other hand, on the downstream end side of the intake pipe 18, a fuel injection nozzle 59 of a fuel injection device for injecting fuel (not shown) into the combustion chamber 17 of the engine 11 is provided in each cylinder of the engine 11 (in this embodiment, four (For a cylinder internal combustion engine), the fuel is injected through the fuel injection nozzle 59 via the solenoid valve 60 that is provided for each cylinder and is duty-controlled by the ECU 15.
Is supplied to. That is, by controlling the opening time of the solenoid valve 60, the amount of fuel supplied to the combustion chamber 17 is adjusted, and a predetermined air-fuel ratio is achieved, so that the spark plug 6 is provided in the combustion chamber 17.
1 to be ignited.

The ECU 15 has a crank angle sensor 6 attached to the engine 11 for detecting the engine speed.
2, a front wheel rotation sensor 66 for detecting the number of rotations of the output shaft 63 of the hydraulic automatic transmission 13 to calculate the average peripheral speed of the pair of left and right front wheels 64, 65, and the throttle body 21. Attached to the throttle lever 24
Throttle opening sensor 67 for detecting the opening of the throttle valve 20 and an idle switch 68 for detecting the fully closed state of the throttle valve 20.
Besides, an air flow sensor 70 such as a Karman vortex flowmeter which is installed in the air cleaner 69 at the tip of the intake pipe 18 and detects the amount of air flowing into the combustion chamber 17 of the engine 11, and is installed in the engine 11. A water temperature sensor 71 for detecting the cooling water temperature of the engine 11, an exhaust temperature sensor 74 installed in the middle of the exhaust pipe 72 for detecting the temperature of exhaust gas flowing in the exhaust passage 73, an ignition key switch 75,
The operating pressure of the power steering device 92 is attached to each of a pair of left and right pressure chambers (not shown) of the power actuator 91 (hereinafter, referred to as power steering pressure).
A pair of pressure sensors 98 and 99 for detecting P _S are connected. Output signals from the crank angle sensor 62, the front wheel rotation sensor 66, the throttle opening sensor 67, the idle switch 68, the air flow sensor 70, the water temperature sensor 71, the exhaust temperature sensor 74, the ignition key switch 75, and the pressure sensors 98, 99. Are sent to the ECU 15, respectively.

Further, a torque calculation unit for calculating a target drive torque of the engine 11 (hereinafter referred to as TCL)
The throttle opening sensor 67 and the idle switch 68 are attached to the throttle body 21, and an accelerator opening sensor 77 for detecting the opening of the accelerator lever 23 and a pair of left and right rear wheels 78, 79, which are driven wheels, are included in the reference numeral 76.
Rear wheel rotation sensors 80, 8 for detecting the respective rotation speeds of the
1, the steering angle sensor 84 for detecting the turning angle of the steering shaft 83 at the time of turning with reference to the straight traveling state of the vehicle 82, and the normal phase of the steering handle 85 integrated with the steering shaft 83 at every 360 degrees (the vehicle 82 is almost The steering shaft reference position sensor 86 for detecting a phase in which a straight traveling state is included) is connected, and output signals from these sensors 77, 80, 81, 84, 86 are respectively sent.

The ECU 15 and the TCL 76 are connected to each other via a communication cable 87. From the ECU 15, the engine speed, the speed of the output shaft 63 of the hydraulic automatic transmission 13, the detection signal from the idle switch 68, and the like are transmitted. In addition to the information on the operating state of the engine 11, information on the road surface μ is sent to the TCL 76. On the contrary, the TCL 76 sends information such as the target drive torque calculated by the TCL 76 and the ignition timing retarding ratio to the ECU 15.

In this embodiment, the front wheels 64, 6 which are the driving wheels.
When the slip amount in the front-rear direction of No. 5 becomes larger than a preset amount, control for lowering the drive torque of the engine 11 to ensure maneuverability and preventing energy loss (hereinafter referred to as slip control Target torque of the engine 11 and the lateral acceleration generated in the turning vehicle (hereinafter referred to as lateral acceleration).
When the engine torque is equal to or greater than a preset value, the engine is controlled when the drive torque of the engine 11 is reduced so that the vehicle does not deviate from the turning circuit (hereinafter referred to as turning control). The target drive torque of the engine 11 is calculated by the TCL 76, and the optimum final target drive torque is selected from these two target drive torques so that the drive torque of the engine 11 can be reduced as necessary. Further, the target retardation amount of the ignition timing is set in consideration of the case where the output of the engine 11 cannot be reduced in time even by the full closing operation of the throttle valve 20 via the actuator 41, and the driving torque of the engine 11 is rapidly reduced. I can do it.

As shown in FIG. 4, which shows the rough flow of the control according to the present embodiment, the target drive torque T _OS of the engine 11 when the slip control is performed and the turning control are performed in the present embodiment. In this case, the target drive torque T _OC of the engine 11 is always calculated in parallel by the TCL 76, and the optimum final target drive torque T _O is selected from these two target drive torques T _OS and T _OC to drive the engine 11. The torque can be reduced if necessary.

Specifically, the control program of the present embodiment is started by turning on the ignition key switch 75, and first at M1, the steering shaft turning position initial value δ _{m (0)} is read, various flags are reset, or this flag is reset. Initial settings such as starting the count of the main timer every 15 milliseconds, which is the control sampling period, are performed.

Then, at M2, the TCL 76 calculates the vehicle speed V and the like based on the detection signals from various sensors, and subsequently, the neutral position δ _M of the steering shaft 83 is learned and corrected at M3. The neutral position δ _M of the steering shaft 83 of the vehicle 82 is represented by EC
Since the initial value δ _{m (0)} is read every time the ignition key switch 75 is turned on because it is not stored in a memory (not shown) in the U15 or the TCL 76, when the vehicle 82 satisfies a straight traveling condition described later. Only the initial value δm ₍₀₎ is learned and corrected until the ignition key switch 75 is turned off.

Next, the target of the TCL 76 for performing slip control for restricting the drive torque of the engine 11 based on the detection signals from the front wheel rotation sensor 66 and the rear wheel rotation sensors 80 and 81 at M4. The driving torque T _OS is calculated, and the engine 1 is operated based on the detection signals from the rear wheel rotation sensors 80 and 81 and the steering angle sensor 84 at M5.
The target driving torque T _OC of the engine 11 when the turning control for restricting the first driving torque is performed is calculated.

Then, in M6, the TCL 76 selects an optimum final target drive torque T _O from these target drive torques T _OS , T _OC by a method described later mainly in consideration of safety. Further, when the vehicle suddenly starts or when the road surface condition suddenly changes from a normal dry road to a frozen road, the actuator 41 is used.
The engine 1 can also be operated by fully closing the throttle valve 20 via the
Since the output reduction of 1 may not be in time, the retard ratio for correcting the basic retard amount p _B is selected based on the change rate G _s of the slip amount s of the front wheels 64 and 65 at M7. Data relating to the retard ratio of the final target drive torque T _O and the basic retard amount p _B is output to the ECU 15 at M8.

When the driver operates a manual switch (not shown) and desires slip control or turning control, the ECU 15 controls the drive torque of the engine 11 to the final target drive torque T _O. The ECU controls the duty ratios of the pair of torque control solenoid valves 51 and 56, and further, based on the data regarding the retardation ratio of the basic retardation amount p _B , this ECU
The target retardation amount p _O is calculated within 15 and the ignition timing P is delayed by the target retardation amount p _O as necessary, whereby the vehicle 8
I try to drive 2 safely and comfortably.

When the driver does not desire slip control or turning control by operating a manual switch (not shown), the ECU 15 controls the pair of solenoid valves 51, 5 for torque control.
As a result of setting the duty ratio 6 to the 0% side, the vehicle 82 enters a normal driving state corresponding to the driver's depression amount of the accelerator pedal 31.

In this way, the drive torque of the engine 11 is changed to M9.
Control until the countdown every 15 milliseconds, which is the sampling period of the main timer, ends, and after that, M2
The steps from to M10 are repeated until the ignition key switch 75 is turned off.

By the way, when the turning control is performed in step M5 to calculate the target drive torque T _OC of the engine 11,
The TCL 76 calculates the vehicle speed V by the following equation (1) based on the detection signals of the pair of rear wheel rotation sensors 80 and 81, and at the same time, based on the detection signal from the steering angle sensor 84, the front wheels 64,
The steering angle δ of 65 is calculated by the following formula (2), and the vehicle 8 at this time is calculated.
The target lateral acceleration G _{YO of 2} is obtained from the following equation (3). V = (V _RL + V _RR ) / 2 (1) δ = δ _H / ρ _H (2) G _YO = δ / {ω · (A + 1 / V ² )} (3)

However, V _RL and V _RR are the peripheral speeds of the pair of left and right rear wheels 78 and 79 (hereinafter referred to as rear wheel speeds), ρ _H is the steering gear speed ratio, and δ _{H is the} steering shaft 83. A turning angle, ω is a wheel base of the vehicle 82, and A is a stability factor of the vehicle 82 described later.

The setting of this stability factor A is shown in FIG.
5. As shown in FIG. 46, after the road surface μ is estimated in step Y1, the stability factor A corresponding to μ is obtained from the estimated road surface μ in step Y2 by map Y3 or by calculation. There are various methods for estimating the road surface μ, such as estimating from the power steering pressure, the steering angle and the vehicle speed, and estimating from the lateral acceleration actually applied to the vehicle during turning, the steering angle and the vehicle speed (details will be described later). When the stability factor A is set, the target lateral acceleration required by the driver is calculated by equation (3) in step Y4, and the longitudinal acceleration (target longitudinal acceleration) G _XO corresponding to the target lateral acceleration is calculated in step Y5. _Is read from a map or the like, and the target drive torque T _OC corresponding to this G _XO is calculated in step Y6. The use of the estimated value of the road surface μ is not limited to the above. In step Y7 of FIG. 46 following step Y6 of FIG. 45, the torque corresponding to the running resistance is corrected. Next, at the time of turning control or slip control, when the torque correction amount corresponding to the lateral acceleration or the longitudinal acceleration is obtained using the map Y9 or the like for performing the torque correction corresponding to the cornering drag in step Y8, the map Y10 is used.
The correction coefficient Kμ according to the road surface μ is obtained by
At 11, the value from the map Y9 is multiplied to obtain the cornering drag correction amount. This allows over-correction on low μ roads and high μ
The lack of correction on the road disappears. And at step Y12,
The torque obtained in step Y6 is added to steps Y7 and Y8.
The target torque T _S is obtained by performing the respective torque corrections in 1. Further, in order to reflect the driver's willingness to accelerate, step Y12
When the target torque T _S obtained by the above and the driver's acceleration required torque T _M determined by the accelerator pedal opening and the engine speed are adopted at an addition ratio of α, the estimated value of the road surface μ is used to Decide. That is, in step Y13, the addition ratio α corresponding to the road surface μ is obtained from the map Y14 and the like, and using this α, in step Y15, the target torque T _OC reflecting the driver's intention is calculated as T _OC = α · T. _S + (1-α) T _M
Ask as. As a result, in the case of the low μ road, the driver's will is less reflected than in the case of the high μ road, and the driver's intention can always be reflected on the turning control and the slip control on the safety side.

As is apparent from the equation (3), the neutral position of the steering shaft 83 may be caused by the toe-in adjustment of the front wheels 64, 65 during the maintenance of the vehicle 82 or the secular change such as the abrasion of the steering gear (not shown). If δ _M changes, the steering shaft 8
A deviation occurs between the turning position δ _m of No. 3 and the actual steering angle δ of the front wheels 64 and 65 which are the steered wheels. As a result, the vehicle 82
The target lateral acceleration G _YO may not be calculated accurately, and it becomes difficult to perform good turning control.
Moreover, during the slip control in the step M4, the cornering drag correction means, which will be described later, corrects the reference drive torque of the engine 11 based on the turning angle δ _H of the steering shaft 83. There is a risk that it will not be possible to perform satisfactorily. Therefore, it is necessary to learn and correct the neutral position δ _M of the steering shaft 83 in the step of M3.

As shown in FIGS. 5, 6 and 7, which shows the procedure for learning and correcting the neutral position δ _M of the steering shaft 83, the TCL
76 determines at H1 whether or not the turning control flag F _C is set. When it is determined in step H1 that the vehicle 82 is under turning control, the output of the engine 11 suddenly changes by learning-correcting the neutral position δ _M of the steering shaft 83, and the riding comfort deteriorates. Because of fear, learning correction of the neutral position δ _M of the steering shaft 83 is not performed.

On the other hand, if it is determined in step H1 that the vehicle 82 is not in the turning control, no problem will occur even if the neutral position δ _M of the steering shaft 83 is learned and corrected.
Based on the detection signals from the rear wheel rotation sensors 80 and 81, the TCL 76 calculates the vehicle speed V for learning the neutral position δ _M at H2 and for turning control which will be described later, using the equation (1). Next, the TCL 76 calculates the difference between the rear wheel speeds V _RL and V _RR (hereinafter referred to as the rear wheel speed difference) | V _RL −V _RR | Reference position sensor 8
6 depending on whether the learning correction of the neutral position [delta] _M is performed in the state in which the reference position [delta] _N of the steering shaft 83 is detected, i.e. the steering angle neutral position in a state where the reference position [delta] _N of the steering shaft 83 is detected It is determined whether or not the learned flag F _HN is set.

Immediately after the ignition key switch 75 is turned on, the steering angle neutral position learned flag F _HN is not set, that is, the neutral position δ _M is learned for the first time.
At H5, it is determined whether or not the steering shaft turning position δ _{m (n)} calculated this time is equal to the steering shaft turning position δ _{m (n-1)} calculated last time. At this time, it is desirable to set the turning detection resolution of the steering shaft 83 by the steering angle sensor 84 to, for example, about 5 degrees so as not to be affected by the hand shake of the driver or the like.

In this step H5, the steering shaft turning position δ _{m (n)} calculated this time is changed to the steering shaft turning position δ calculated last time.
When it is determined that the vehicle speed V is equal to _{m (n-1),} it is determined at H6 whether the vehicle speed V is greater than a preset threshold value _VA . This operation is necessary because the rear wheel speed difference | V _RL −V _RR | and the like due to steering cannot be detected unless the vehicle 82 reaches a certain high speed, and the threshold value V _A is the traveling characteristic of the vehicle 82. For example, 10 km / h is set as appropriate by experiments based on the above. When it is determined in step H6 that the vehicle speed V is equal to or higher than the threshold value V _A , the TCL 76 sets the rear wheel speed difference | V _RL -V _RR | It is determined whether or not it is smaller than the threshold value V _X , that is, whether the vehicle 82 is in a straight traveling state. Here, not to the threshold value V _X per hour 0km left and right rear wheels 7
If the tire pressures at 8,79 are not equal, the vehicle 82
Although the vehicle is in a straight running state, a pair of left and right rear wheels 7
This is in order to avoid that the vehicle 82 is not determined to be in the straight traveling state due to the difference in the peripheral velocities V _RL and V _{RR of} 8,79.

If the tire pressures of the left and right rear wheels 78 and 79 are not equal, the rear wheel speed difference | V _RL -V _RR | tends to increase in proportion to the vehicle speed V. For example, _X may be mapped as shown in FIG. 8 and the threshold value V _X may be read from this map based on the vehicle speed V.

At this step H7, the rear wheel speed difference | V _RL −
V _RR | if is equal to or less than the threshold value V _X, the steering shaft reference position sensor 86 is a reference position of the steering shaft 83 at H8 [delta]
Determine whether _N is detected. And this H8
In the step, the steering shaft reference position sensor 86
And it detects the reference position [delta] _N, i.e., when the vehicle 82 is determined to be running straight begins a first count of the learning timer (not shown) incorporated in the TCL76 at H9.

Next, the TCL 76 determines at H10 whether or not 0.5 seconds has elapsed from the start of counting by the first learning timer, that is, whether or not the straight traveling state of the vehicle 82 has continued for 0.5 seconds. , From the start of counting this first learning timer
If 0.5 seconds has not elapsed, it is determined in H11 whether the vehicle speed V is higher than the threshold value V _A. When it is determined in step H11 that the vehicle speed V is higher than the threshold value _VA , the rear wheel speed difference | V _RL -V _RR |
It is determined whether or not it is equal to or less than a threshold value V _{B such} as km. This H
Rear wheel speed difference at 12 steps | V _RL -V _RR | is equal to or less than the threshold value V _B, i.e., if the vehicle 82 is determined to be running straight, not shown, incorporated in the TCL76 at H13 The second learning timer starts counting. Then, in H14, it is determined whether or not 5 seconds have elapsed since the second learning timer started counting, that is, whether or not the straight traveling state of the vehicle 82 has continued for 5 seconds, and the second learning timer starts counting. If 5 seconds have not passed from the
Returning to step 2, the operations from step H2 to step H14 are repeated.

At the step H8 in the middle of this repetitive operation, the steering shaft reference position sensor 86 detects the reference position δ _{N of the} steering shaft 83.
Is detected, the counting of the first learning timer is started in step H9, and 0.5 seconds have elapsed from the start of counting the first learning timer in H10.
That is, when it is determined that the straight traveling state of the vehicle 82 has continued for 0.5 seconds, the steering angle neutral position learned flag F _HN in the state where the reference position δ _N of the steering shaft 83 is detected at H15 is set. , H16, it is further determined whether or not the steering angle neutral position learned flag F _H when the reference position δ _N of the steering shaft 83 is not detected is set. Also, if it is determined in step H14 that 5 seconds have elapsed since the start of counting of the second learning timer, the process shifts to step H16.

In the above operation, since the steering angle neutral position learned flag F _H in the state where the reference position δ _N of the steering shaft 83 has not been detected yet is set, the reference position of the steering shaft 83 is set in this step H16. If the steering angle neutral position learned flag F _H in the state where δ _N is not detected is not set, that is, the neutral position δ _M is first learned when the reference position δ _N of the steering shaft 83 is detected. At H17, the current steering shaft turning position δ _{m (n)} is regarded as the new steering shaft 83 neutral position δ _{M (n),} and this is read into the memory in the TCL 76 and the reference position δ of the steering shaft 83 is read. The rudder angle neutral position learned flag F _H is set when _N is not detected.

After the new neutral position δ _{M (n)} of the steering shaft 83 is set in this way, the neutral position δ of the steering shaft 83 is set.
While calculating the turning angle [delta] _H of the steering shaft 83 and _M as a reference, a count of the learning timer is cleared at H18,
The steering angle neutral position learning is performed again.

When it is determined in step H5 that the steering axis turning position δ _{m (n)} calculated this time is not equal to the steering axis turning position δ _{m (n-1)} calculated last time, In the step of, the vehicle speed V is not equal to or higher than the threshold value _VA, that is, H1.
Wheel speed difference after calculated by the second step | V _RL -V _RR | when it is determined that there is no reliable, or the rear wheel differential velocity determined in step H12 | V _RL -V _RR | is threshold V _B If it is determined that the vehicle 82 is not in the straight traveling state, the flow shifts to step H18.

In the step H7, the rear wheel speed difference | V
If you are determined to be larger than the threshold value V _X, | _RL -V _RR
If the steering shaft reference position sensor 86 at H8 step is determined not to detect the reference position [delta] _N of the steering shaft 83, and clears the count of the first learning timer at H19, the H11 Move to step,
If the vehicle speed V is determined to be equal to or lower than the threshold value _{VA in} the step (i), it is not possible to determine that the vehicle 82 is in a straight-ahead state.

On the other hand, in step H4, the steering shaft 83
When the steering angle neutral position learned flag F _HN is set in the state where the reference position δ _N is detected, that is, when it is determined that the learning of the neutral position δ _M is the second time or later, H20 is executed. The steering shaft reference position sensor 86 detects the reference position δ of the steering shaft 83.
Determine whether _N is detected. And this H2
At step 0, the steering shaft reference position sensor 86
When the third reference position [delta] _N is determined to be detected,
At H21, it is determined whether or not the vehicle speed V is greater than a preset threshold value _VA .

At this step H21, the vehicle speed V becomes the threshold value V.
If it is determined that the value is equal to or greater than _A ,
V _RL -V _RR | | whether the smaller than the threshold value V _X, i.e. the vehicle 82 determines whether the running straight rear wheel speed difference at. Then, the rear wheel speed difference is determined in step H22 | V _RL -V _RR | If it is determined that less than the threshold value V _X, currently calculated steering shaft turning position δ _{m (n)} is the last time at H23 It is determined whether the calculated value is equal to the calculated steering shaft turning position Δm _(n-1) . If it is determined in step H23 that the currently calculated steering shaft turning position δm _(n) is _equal to the previously calculated steering shaft turning position δm _(n-1) , then in H24 the first shaft turning position δm _(n-1) is determined. The learning timer starts counting.

Next, the TCL 76 determines at H25 whether or not 0.5 seconds has elapsed from the start of counting by the first learning timer, that is, whether or not the straight traveling state of the vehicle 82 has continued for 0.5 seconds. , 0.5 from the start of counting the first learning timer
If the second has not elapsed, the process returns to the step H2, and the steps H2 to H4 and H20 to H25 are repeated. On the contrary, if it is determined in step H25 that 0.5 second has elapsed from the start of counting by the first learning timer, the process proceeds to step H16.

If it is determined in step H20 that the steering shaft reference position sensor 86 has not detected the reference position δ _N of the steering shaft 83, or if the vehicle speed V is equal to or higher than the threshold value V _{A in} step H21. No, that is, when it is determined that the rear wheel speed difference | V _RL −V _RR | calculated in the step H22 is not reliable, or in the step H22, the rear wheel speed difference | V
If you are determined to be larger than the threshold value V _X, | _RL -V _RR
Steering axis turning position δ calculated this time in step H23
_{m (n)} is the case where it is determined not equal to the steering shaft pivoted position previously calculated δ _{m (n-1),} both the process proceeds to step of the H18.

In step H16, the steering angle neutral position learned flag F _H is set, that is, the neutral position δ.
If it is judged that _M has learned the second time or later, TCL7
6, the current steering shaft turning position δm _(n) is _equal to the previous neutral position δM _(n-1) of the steering shaft 83 at H26, that is, δm _(n) = δM _(n-1) . Determine if there is. If it is determined that the current steering shaft turning position δ _{m (n)} is _equal to the previous neutral position δ _{M (n-1)} of the steering shaft 83, the process directly proceeds to step H18, and the next steering angle neutral position is determined. Position learning is performed.

At step H26, the current steering shaft turning position δ _{m (n)} is not equal to the previous neutral position δ _{M (n-1)} of the steering shaft 83 due to play in the steering system. If so, in the present embodiment, the current steering shaft turning position δ _{m (n)} is not judged as it is as the new steering shaft 83 neutral position δ _{M (n),} and the absolute value of these differences is corrected in advance. If the difference is equal to or more than the limit amount Δδ, a value obtained by subtracting or adding the correction limit amount Δδ from the previous steering shaft turning position δ _{m (n-1) is} added to the neutral position δ _M of the new steering shaft 83. _(n), and this is TCL7
6 to be read into the memory.

That is, the TCL 76 sets the current neutral position δ of the steering shaft 83 from the current steering shaft turning position δ _{m (n)} at H27.
_The value obtained by subtracting _{M (n-1)} is a preset negative correction limit amount-Δ
It is determined whether it is smaller than δ. And this H27
When it is determined that the value subtracted in the step is smaller than the negative correction limit amount -Δδ, the neutral position δ _{M (n)} of the new steering shaft 83 is changed to the neutral position of the previous steering shaft 83 at H28. From the position δ _{M (n-1)} and the negative correction limit amount −Δδ, change δ _{M (n)} = δ _{M (n-1)} −Δδ, and the learning correction amount per time is unconditionally negative. Care is taken not to become too large.

As a result, even if the steering angle sensor 84 outputs an abnormal detection signal for some reason,
Neutral position [delta] _M of the steering shaft 83 is not in the sudden change, it is possible to cope with the abnormality quickly.

On the other hand, when it is determined that the value subtracted in step H27 is larger than the negative correction limit amount −Δδ, the steering wheel turning position δ _{m (n)} from the current steering shaft turning position δ _{m (n)} to the previous steering shaft is determined in H29. It is determined whether the value obtained by subtracting the neutral position δ _{M (n-1)} of 83 is larger than the positive correction limit amount Δδ. The value subtracted in the step of H29 is a positive correction limit Δ
If it is determined that the value is larger than δ, the neutral position δ _{M (n)} of the new steering shaft 83 is set to a positive correction limit amount Δδ with the neutral position δ _{M (n-1)} of the previous steering shaft 83 at H30. And from δ _{M (n)} = δ
_It is changed to _{M (n-1)} + Δδ so that the learning correction amount per time does not unconditionally increase to the positive side.

As a result, even if the steering angle sensor 84 outputs an abnormal detection signal for some reason,
Neutral position [delta] _M of the steering shaft 83 is not in the sudden change, it is possible to cope with the abnormality quickly. However, H2
If it is determined that the value subtracted in step 9 is smaller than the positive correction limit amount Δδ, the current steering shaft turning position δ _{m (n) is changed} to the neutral position δ _M of the new steering shaft 83 at H31. Read as it is as _(n) .

As described above, in this embodiment, when the neutral position δ _M of the steering shaft 83 is learned and corrected, the rear wheel speed difference | V _RL -V _RR |
In addition to using only the steering shaft reference position sensor 86, a method is also used in which the detection signal from the steering shaft reference position sensor 86 is used together, and the neutral position δ _M of the steering shaft 83 is learned and corrected relatively early after the vehicle 82 has started. In addition, the steering shaft reference position sensor 86
There rear wheel speed difference also failed for some reason | V _RL -V _RR | only neutral position [delta] _M of the steering shaft 83 can learn corrected, it is excellent in safety.

Therefore, when the stopped vehicle 82 starts with the front wheels 64 and 65 kept in the turning state, as shown in FIG. 9 showing an example of the changing state of the neutral position δ _M of the steering shaft 83 at this time. When the learning control of the neutral position δ _M of the steering shaft 83 is the first time, the correction amount from the initial value δ _{m (0)} of the steering shaft turning position in the above-mentioned step M1 becomes very large, but the second time. The subsequent neutral position δ _M of the steering shaft 83 is H1.
By the operation in steps H7 and H19, the state is suppressed.

In this way, the neutral position δ _{M of the} steering shaft 83
After learning correction, the target drive torque T _OS for performing slip control for regulating the drive torque of the engine 11 based on the detection signal from the front wheel rotation sensor 66 and the detection signals from the rear wheel rotation sensors 80 and 81 is calculated. Calculate.

By the way, the coefficient of friction between the tire and the road surface can be regarded as equivalent to the rate of change of the vehicle speed V applied to the vehicle 82 (hereinafter referred to as longitudinal acceleration) G _X, and therefore, in the present embodiment. The longitudinal acceleration G _X is calculated based on the detection signals from the rear wheel rotation sensors 80 and 81, and the reference drive torque T _B of the engine 11 corresponding to the maximum value of the longitudinal acceleration G _X is detected from the front wheel rotation sensor 66. The target drive torque T _OS is calculated based on the deviation (hereinafter, referred to as slip amount) s between the front wheel speed V _F and the target front wheel speed V _FO corresponding to the vehicle speed V.

As shown in FIG. 10 and FIG. 11 showing the calculation block for calculating the target drive torque T _OS of the engine 11, first, the TCL 76 outputs the vehicle speed V _S for slip control from the rear wheel rotation sensors 80, 81. In the present embodiment, the smaller one of the two rear wheel speeds V _RL and V _RR is used as the first vehicle speed V _S for slip control by the low vehicle speed selection unit 101. Then, the high vehicle speed selection unit 102 selects the larger one of the two rear wheel speeds V _RL and V _RR as the second vehicle speed V _S for slip control, and then selects the second value by the changeover switch 103. Two selectors 101, 102
Which of the outputs is to be taken is further selected.

In this embodiment, the first vehicle speed V _S selected by the low vehicle speed selection unit 101 is two rear wheel speeds V _RL , V
The smaller value V _L of _RR is multiplied by the weighting coefficient K _V corresponding to the vehicle speed V calculated by the above equation 1 in the multiplication unit 104, and this is multiplied by two rear wheel speeds V _RL , V _RR . It is calculated by adding the larger value V _H of these values and (1-K _V ) multiplied by the multiplication unit 105.

That is, the engine 11 is actually controlled by slip control.
In the state where the driving torque of the vehicle is reduced, that is, the slip control flag F _S is set, the smaller value of the two rear wheel speeds V _RL and V _RR is selected as the vehicle speed V _S by the changeover switch 103. and a state in which the drive torque is not reduced in the engine 11 even if the driver wants to slip control, that is in the slip control flag F _S is reset state, after the two wheel speed V _RL, among V _RR Is selected as the vehicle speed V _S.

This is because it is difficult to shift from the state where the drive torque of the engine 11 is not reduced to the state where the drive torque of the engine 11 is reduced, and at the same time, the transition in the opposite case is also difficult. For example, when the smaller one of the two rear wheel speeds V _RL , V _RR during the turning of the vehicle 82 is selected as the vehicle speed V _S , the slip occurs even though the front wheels 64, 65 do not slip. Is determined to occur, and the driving torque of the engine 11 is temporarily reduced in consideration of the traveling safety of the vehicle 82 in order to avoid such a problem that the driving torque of the engine 11 is reduced. This is because consideration has been given to keep this state.

When the vehicle speed V _S is calculated by the low vehicle speed selection unit 101, the weighting coefficient K _{V is applied} to the multiplication unit 104 by the smaller value V _L of the two rear wheel speeds V _RL and V _RR. For example, it is possible to multiply by a value obtained by multiplying the larger value V _H of the two rear wheel speeds V _RL and V _RR by (1-K _V ) in the multiplication unit 105, When traveling in a turning circuit having a small radius of curvature such as turning to the left or right, the average value of the peripheral speeds of the front wheels 64 and 65 and the smaller value V _{L of the} two rear wheel speeds V _RL and V _RR are used. As a result, the correction amount of the drive torque by feedback becomes too large, and the acceleration of the vehicle 82 may be impaired.

In this embodiment, the weighting coefficient K
_V is read from the map as shown in FIG. 12 based on the vehicle speed V of the equation 1 which is the average value of the peripheral speeds of the rear wheels 78 and 79.

The longitudinal acceleration G _X is calculated based on the thus calculated slip control vehicle speed V _S. First, the vehicle speed V _{S (n)} calculated this time and the vehicle speed V _S calculated one time before are calculated.
_{From S (n−1)} , the current longitudinal acceleration G _{X (n)} of the vehicle 82 is calculated by the differential operation unit 106 as in the following equation. G _{X (n)} = (VS _(n) -VS _(n-1) ) / (3.6 · Δt · g) where Δt is the sampling period of this control, which is 15 milliseconds, and g is the gravitational acceleration. Is.

The calculated longitudinal acceleration G _{X (n)} is 0.
When it becomes 6 g or more, considering the safety against a calculation error, etc., in order to prevent the maximum value of this longitudinal acceleration G _{X (n) from} exceeding 0.6 g, the longitudinal acceleration G _{X ( n)}
Clip to 0.6g. Further, the filter unit 108 performs a filtering process for removing noise to calculate a corrected longitudinal acceleration G _XF .

In this filtering process, since the longitudinal acceleration G _{X (n)} of the vehicle 82 can be regarded as equivalent to the friction coefficient between the tire and the road surface, the longitudinal acceleration G _{X of} the vehicle 82 is determined.
_{Even if} the maximum value of _{X (n)} changes and the slip ratio S of the tire is likely to deviate from the target slip ratio S _O corresponding to the maximum value of the coefficient of friction between the tire and the road surface or the vicinity thereof, the slip of the tire may be reduced. The longitudinal acceleration G _{X (n) is} set so that the rate S is maintained at or less than the target slip rate S _O corresponding to the maximum value of the coefficient of friction between the tire and the road surface.
Is corrected, and is specifically performed as follows.

When the longitudinal acceleration G _{X (n) of} this time is _{equal to} or greater than the previous corrected longitudinal acceleration G _{XF (n-1)} which has been filtered, that is, when the vehicle 82 continues to accelerate, the corrected longitudinal acceleration G of this time. _{XF (n) is set} to G _{XF (n)} = (28/256) · Σ {G _{X (n)} −G _{XF (n-1)} }, and noise is removed by delay processing, and the corrected longitudinal acceleration G _{XF (n)} To follow the longitudinal acceleration G _{X (n)} relatively quickly.

When the longitudinal acceleration G _{X (n)} of this time is less than the corrected longitudinal acceleration G _{XF (n-1) of the} previous time, that is, when the vehicle 82 is not accelerated too much, the following processing is performed every sampling period Δt of the main timer. I do.

When the slip control flag F _S is not set, that is, when the drive torque of the engine 11 is not reduced by the slip control, the vehicle 82 is decelerating. G _{XF (n)} = G _{XF (n -1)} -0.002 is used to suppress the decrease in the corrected longitudinal acceleration G _{XF (n)} , and the responsiveness to the acceleration request of the vehicle 82 by the driver is secured.

Further, the vehicle 82 is in deceleration even when the slip amount s is positive while the drive torque of the engine 11 is being reduced by the slip control, that is, the front wheels 64 and 65 are slightly slipped. Therefore, since there is no problem in safety, G _{XF (n)} = G _{XF (n-1)} -0.002 is set to suppress the decrease in the corrected longitudinal acceleration G _{XF and} the responsiveness to the acceleration request of the vehicle 82 by the driver is suppressed. Have secured.

Further, when the slip torque s of the front wheels 64 and 65 is negative while the drive torque of the engine 11 is being reduced by the slip control, that is, when the vehicle 82 is decelerating, the maximum value of the corrected longitudinal acceleration G _XF is set to the maximum value. Hold and drive the vehicle 8
2 to ensure responsiveness to acceleration requests.

Similarly, while the drive torque of the engine 11 is being reduced by the slip control, while the hydraulic control device 16 is shifting up the hydraulic automatic transmission 13, a feeling of acceleration for the driver is secured.

The corrected longitudinal acceleration G _XF from which noise has been removed by the filter unit 108 is converted into torque by the torque conversion unit 109. The value calculated by this torque conversion unit 109 is, of course, However, since it should be a positive value, the clipping resistance is clipped to 0 or more in order to prevent a calculation error in the clipping unit 110, and then the running resistance calculation unit 1
The running resistance T _R calculated in 11 adds at adding unit 112, the cornering drag correction torque T _C calculated by the cornering drag correction amount calculating unit 113 further based on the detection signal from the steering angle sensor 84 Adder 114
Then, the reference driving torque T _B shown in the following equation (4) is calculated. In _{T B = G FO · W b} · r + T R + T C ... (4) where, W _b is the body weight, r is an effective radius of the front wheel 64, 65.

The running resistance T _R can be calculated as a function of the vehicle speed V, but in this embodiment, it is calculated from the map shown in FIG. In this case, since the running resistance T _R is different between flat road and an uphill road, in the map drawing, and uphill road shown by a flat road and two-dot chain line indicated by the solid line is written, incorporated in the vehicle 82 One of them is selected based on a detection signal from a tilt sensor (not shown).
It is also possible to set _R.

Further, in the present embodiment, the cornering drag correction torque T _C is obtained from the map shown in FIG.
It can be set in the reference driving torque T _B, since the reference driving torque T _B of the turning immediately after the engine 11 is in the large acceleration feeling of the vehicle 82 after exiting the turning path is improved. Further, since the cornering drag correction torque T _C originally changes according to the road surface μ, the road surface μ estimating means 113A estimates the road surface μ, and the cornering drag correction amount calculation unit 113 causes the map Y in FIG.
The coefficient Kμ corresponding to the road surface μ is read from 10, and the value obtained from the map of FIG. 14 is multiplied to obtain the cornering drag correction torque T _C. It is assumed that the coefficient Kμ is 0.3 in the low μ range and 1.0 in the high μ range, and that it changes from 0.3 to 1.0 with the increase of μ in the middle.

Here, an example of the estimation method of the road surface μ estimation means 113A will be described with reference to FIGS. 47 to 54. First, as shown in FIG. 48 showing the steering state of the right front wheel 65, the cornering force D generated in the front wheel 65 during turning.
_F is given by the following equation (5). D _F ∝δ _F · μ (5) where δ _F is the side slip angle of the front wheel 65 with respect to the traveling direction of the vehicle 82 (the front-rear direction of the vehicle 82 corresponds to the vertical direction in the figure), and μ is the friction coefficient of the road surface. Is. Where the sideslip angle δ
_As shown in FIG. 49 showing the relationship between _F and the cornering force D _F , even if the sideslip angle δ _F is a constant value, the cornering force D _F greatly varies depending on the road surface condition, and generally the road surface μ is The larger the value, the larger the side slip angle δ _F. Further, as is clear from FIG. 48, the cornering force D _F and the power steering pressure P _S are in a substantially proportional relationship due to a mechanical relationship, so that C
_{When 1} is a proportionality constant, equation (5) can be modified and expressed as equation (6) below. P _S = C ₁ · δ _F · μ (6) On the other hand, since the sideslip angle δ _F can be expressed by the following equation (7), the power steering pressure P _S and the steering are calculated from the equation (6) and this equation (7). The ratio to the shaft turning angle δ _H , that is, P _S / δ _H is given by the following equation (8). δ _F = C ₂ · V ² · δ _H / (μ + C ₃ · V ² ) ... (7) P _S / δ _H = μ · C ₁ · C ₂ · V ² / (μ + C ₃ · V ² ) ... (8) However, C ₂ and C ₃ are constants. Therefore, the road surface μ can be calculated by the equation (8) based on the power steering pressure P _{S, the} steering shaft turning angle δ _H, and the vehicle speed V output to the road surface μ estimating means 113A.

As shown in FIG. 50 showing the calculation procedure by the road surface μ estimating means 113A, the power steering pressure P _S calculated based on the detection signals from the pressure sensors 98 and 99 is
After the power steering pressure P _S , which is the absolute value of the differential pressure between the pressures P _LS and P _RS in the pressure chamber of the power actuator 91 detected by these pressure sensors 98 and 99, is calculated by the subtraction unit 157, the phase compensation filter 158 is set. Via the road surface μ calculation unit 15
9 is output. The steering shaft turning angle δ _H calculated based on the detection signal from the steering angle sensor 84 and the vehicle speed V calculated based on the detection signals from the rear wheel rotation sensors 80 and 81 are transmitted through the communication cable 87 from the TCL 76. The output is output to the road surface μ calculating unit 159 via this. The phase compensation filter 158 to remove the noise in the signal corresponding to the power steering pressure P _S which is output from the subtraction unit 157, the power steering pressure P _S to the steering shaft turning angle [delta] _H in steering transition of the steering wheel 85 This is for compensating for the phase lead of. That is, as shown in FIG. 51 showing the relationship between the change in the steering shaft turning angle δ _{H and} the change in the power steering pressure P _S at the time of steering, when the phase compensation filter 158 is not used, the characteristics of the steering valve 94 result. Then, as indicated by the solid line in the figure, the power steering pressure P _S rises early and greatly with respect to the change of the steering shaft turning angle δ _H accompanying the turning of the steering handle 85, and the steering accompanying the turning back of the steering handle 85 The power steering pressure P _S tends to fall earlier with respect to the change of the shaft turning angle δ _H. However, by using the phase compensation filter 158, as shown by the broken line in the figure, the change in the power steering pressure P _S is caused to follow the change in the steering shaft turning angle δ _H without causing a phase shift, it is possible to remove the phase advance of the power steering pressure P _S in the steering transition of the steering wheel 85. The road surface μ calculated by the road surface μ calculation unit 159 is the μ change limiting unit 160 and the road surface μ.
Is output via a stabilizing filter 161 for stabilizing the value of. When the rate of change of the road surface μ is within a predetermined range, the μ fluctuation limiting unit 160 outputs the output to the stabilization filter 161 for the road surface μ calculated by the road surface μ calculation unit 159, thereby stabilizing the output. To do.

FIG. 52 showing the flow of this operation for estimating the road surface μ.
As shown in FIG. 53, first, at J1, the rear wheel speed sensor 8
0, 81, steering angle sensor 84, and pressure sensor 98, 9
The vehicle speed V calculated based on the detection signals from 9
And the steering shaft turning angle δ _H and the pressures P _LS and P _{RS in} the pressure chamber of the power actuator 91, respectively, and then at J2, the pressure difference between the pressures P _LS and P _RS in the pressure chamber of the power actuator 91, that is, the power steering. The pressure P _S is calculated. Then, the power steering pressure P _S is subjected to the processing by the phase compensation filter 158 described above at J3, and
Whether the steering axis turning angle δ _H is not 0 at J4, or whether the steering axis turning angle δ _{H (n)} calculated this time is the same as the steering axis turning angle δ _{H (n-1)} calculated last time It is determined whether or not. This J
The steering axis turning angle δ _H is 0 in step 4, or the steering axis turning angle δ _{H (n)} calculated this time is not the same as the steering axis turning angle δ _{H (n-1)} calculated last time. If it is determined that the steering shaft turning angle δ _H is not 0 in step J4, the steering shaft turning angle δ _{H (n)} calculated this time is calculated last time. Steering axis turning angle δ
_When it is determined that it is the same as _{H (n-1)} , it is determined in J5 whether or not the absolute value of the steering shaft turning angle δ _H is equal to or greater than a preset predetermined value δ _H1 (for example, 10 degrees). . If it is determined in step J5 that the absolute value of the steering axis turning angle δ _H is less than the predetermined value δ _H1 , the process returns to step J1. However, in step J5, the steering axis turning angle δ _H When it is determined that the absolute value is equal to or greater than the predetermined value δ _H1 , the ratio of the power steering pressure P _S and the steering shaft turning angle δ _H , that is, P _S / δ _H is calculated in J6 by the equation (8). To be done.

Thereafter, at J7, whether the power steering pressure P _S is positive or negative and the steering shaft turning angle δ _H is positive or negative, that is, P _S
/ Sign of [delta] _H is positive or not is determined. If it is determined in step J7 that the sign of P _S / δ _H is negative, the power steering pressure P _S and the steering shaft turning angle δ _H are caused by the phase compensation filter processing in step J3. It is determined that the phase inversion has occurred during the period, and the process returns to step J1.
If it is determined in step J7 that the sign of P _S / δ _H is positive, the multiplication coefficient K _m for calculating the road surface μ is read from J8 in the map as shown in FIG. This map is obtained by defining a multiplication factor K _m corresponding to the vehicle speed V, the stored in a memory not shown in advance in the ECU 15.

Here, if the equation (8) is modified, μ = P _S · {1 + C ₃ · V ² / (C ₁ · C ₂ · V ² )} / δ _H , but the multiplication coefficient K _m is K _{This corresponds to m} = 1 + C ₃ · V ² / (C ₁ · C ₂ · V ² ). Therefore, the road surface μ can be expressed by the following equation. _{μ = P S · K m /} δ H

Next, the ratio P _S / [delta] _H of the calculated and the power steering pressure P _S and the steering shaft turning angle [delta] _H in step multiplication factors K _m and J6 read at J8 step at J9 The road surface μ is calculated by multiplying by. After this, J1
At 0, it is determined whether or not the absolute value of the rate of change dμ / dt of the road surface μ is within a predetermined value Δμ (for example, 0.2μ per second) set in advance. If it is determined in step J10 that the absolute value of the change rate dμ / dt of the road surface μ exceeds the predetermined value Δμ, the process returns to step J1.
When it is determined that the absolute value of the change rate dμ / dt of the road surface μ is within the predetermined value Δμ in the step 0, the value of the road surface μ calculated in the step J9 is stabilized.
After the stabilization filter processing is performed at 11, the road surface μ is output at J12.

[0091] Note that by the absolute value of the steering shaft turning angle [delta] _H in step J5 In this embodiment it is determined whether a predetermined value [delta] _H1 above, the steering shaft turning angle [delta] _H is a predetermined value [delta] _H1
For more, i.e. the front wheels 64 and 65 is steered substantially the power steering pressure P _S rises, moreover, whether the positive and negative polarity and the steering shaft turning angle [delta] _H of the power steering pressure P _S is the same at J7 step By determining whether or not the road surface μ is calculated only when the directions of the power steering pressure P _S and the steering shaft turning angle δ _H are the same, the road surface μ can be accurately estimated. That is, the characteristics of the steering valve 94 and the front wheels 64, 6
The road surface μ can be accurately calculated by removing the influence of inertia and the like associated with the steering of No. 5. On the other hand, if any one of the determination processes in the steps J4, J5, and J7 is negative, the processes after the step J8 are not performed, and in this case, the road surface μ calculated last time remains unchanged. Will be output. Further, in this embodiment, even if the processing after the step of J8 is executed and the road surface μ is calculated, if the change rate dμ / dt of the road surface μ is larger than the predetermined value Δμ, the determination in the step J10 is made. Even if the value of the road surface μ is not updated by the operation, and even if the determination in step S10 is positive, the road surface μ is output through the stabilizing filter process, and therefore the value is output. The road surface μ does not change abruptly and its value becomes stable. Further, in this embodiment, the power steering pressure P _S
At the time of detecting, the pressure in the left and right pressure chambers of the power actuator 91 is detected by the pair of pressure sensors 98, 99,
It was to calculate the differential pressure of the pressure chamber as a power steering pressure P _S, it is also possible to detect on the basis of the power steering pressure P _S in the output from one pressure sensor incorporated in the discharge side of the hydraulic pump 95 is there. The road surface μ estimated by the road surface μ estimating means 113A is used not only for cornering drag correction but also for setting the stability factor A and calculating the addition ratio α for reflecting the driver's intention.

Next, with respect to the reference drive torque T _B calculated by the equation (4), the variable clip portion 11 is used in this embodiment.
By setting the lower limit value at 5, the final correction torque T _PID which will be described later from the reference driving torque T _B subtracting unit 11
The problem that the value subtracted in step 6 becomes negative is prevented. As shown in the map shown in FIG. 15, the lower limit value of the reference drive torque T _B is gradually reduced according to the elapsed time from the start of slip control.

On the other hand, the TCL 76 calculates the actual front wheel speed V _F based on the detection signal from the front wheel rotation sensor 66, and based on the front wheel speed V _F and the vehicle speed V _S for slip control as described above. The feedback control of the reference drive torque T _B is performed by using the slip amount s which is the deviation from the target front wheel speed V _FS for correction torque set based on the target front wheel speed V _FO set by The target drive torque T _OS of 11 is calculated.

By the way, in order to make effective use of the drive torque generated in the engine 11 when the vehicle 82 is accelerated, FIG.
As shown by the solid line in the middle, the slip ratio S of the tires of the running front wheels 64 and 65 is smaller at or near the target slip ratio S _O corresponding to the maximum value of the coefficient of friction between the tire and the road surface. It is desirable to adjust the values so as to avoid energy loss and not to impair the steering performance and acceleration performance of the vehicle 82. S = (V _D −V)
/ V. V is the vehicle speed, and V _D is the peripheral speed of the drive wheels.

Here, it is known that the target slip ratio S _O swings in the range of about 0.1 to 0.25 depending on the condition of the road surface.
It is desirable that the front wheels 64 and 65, which are drive wheels, generate a slip amount s of about%. In consideration of the above points, the target front wheel speed _VFO is set by the multiplication unit 117 according to the following equation. V _FO = 1.1 · V Then, the TCL 76 reads the slip correction amount V _K corresponding to the above-mentioned corrected longitudinal acceleration G _XF from the map as shown in FIG.
In step 9, the target front wheel speed _VFO for reference torque calculation is added. Although the slip correction amount V _K has a tendency to increase stepwise as the value of the corrected longitudinal acceleration G _XF increases, in the present embodiment, this map is created based on a running test or the like. I have.

As a result, the target front wheel speed V _FS for calculating the correction torque is increased, and the slip ratio S at the time of acceleration becomes smaller than the target slip ratio S _O shown by the solid line in FIG. 16 or in the vicinity thereof. Is set to.

On the other hand, the relationship between the friction coefficient between the tire and the road surface during turning and the slip ratio S of this tire is shown in FIG.
As shown by the one-dot chain line therein, the tire slip rate at which the maximum value of the friction coefficient between the tire and the road surface during turning is:
It can be seen that the target slip ratio S _{O of the} tire, which is the maximum value of the coefficient of friction between the tire and the road surface while traveling straight, is considerably smaller. Therefore, it is desirable to set the target front wheel speed _VFO smaller than when the vehicle 82 is traveling straight so that the vehicle 82 can smoothly turn when the vehicle 82 is turning.

Therefore, the turning correction unit 120 reads the slip correction amount V _KC corresponding to the target lateral acceleration G _YO from the map shown by the solid line in FIG. 18, and subtracts it from the map.
_Is subtracted from the target front wheel speed _VFO for calculating the reference torque. However, since the turning angle δ _H of the steering shaft 83 is not reliable until the first learning of the neutral position δ _M of the steering shaft 83 performed after the ignition key switch 75 is turned on, the rear wheel 78, The vehicle 82 by the peripheral speeds V _RL and V _RR of 79
The slip correction amount V _KC is read from the map as shown by the broken line in FIG. 18 on the basis of the lateral acceleration G _Y that actually acts on.

By the way, the target lateral acceleration G _YO is calculated by the equation (3) using the steering angle δ by calculating the steering angle δ by the equation (2) based on the detection signal from the steering angle sensor 84. At the same time, the neutral position δ _M of the steering shaft 83 is learned and corrected.

Therefore, when an abnormality occurs in the steering angle sensor 84 or the steering axis reference position sensor 86, the target lateral acceleration G _YO
May be completely wrong. Therefore, if an abnormality occurs in the steering angle sensor 84 or the like, the rear wheel speed difference |
Using V _RL −V _RR |, the actual lateral acceleration G _Y occurring in the vehicle 82 is calculated, and this is used instead of the target lateral acceleration G _YO .

Specifically, the actual lateral acceleration G _Y is calculated by the following equation (9) in the lateral acceleration computing unit 122 incorporated in the TCL 76 from the rear wheel speed difference | V _RL −V _RR | and the vehicle speed V. The corrected lateral acceleration G _{YF obtained} by _performing noise removal processing in the filter unit 123 is used. _{G Y = | V RL -V RR} | · V / (3.6 2 · b · g) ... (9)

However, b is the tread of the rear wheels 78 and 79, and the lateral acceleration G calculated this time is calculated in the filter section 123.
Low-pass processing is performed on the corrected lateral acceleration G _{YF (n)} of this time from _{Y (n)} and the corrected lateral acceleration G _{YF (n-1)} calculated last time by digital calculation shown in the following equation. G _{YF (n)} = Σ (20/256) {G _{Y (n)} −G _{YF (n-1)} }

Whether an abnormality has occurred in the steering angle sensor 84 or the steering shaft reference position sensor 86 is determined by, for example, FIG.
Can be detected by the TCL 76 by the disconnection detection circuit shown in FIG. That is, the outputs of the steering angle sensor 84 and the steering shaft reference position sensor 86 are pulled up by the resistor R and grounded by the capacitor C, and the outputs are directly used as T
While inputting to the A0 terminal of CL76 for various controls,
The signal is input to the A1 terminal through the comparator 88.
The negative terminal of the comparator 88 has a reference voltage of 4.5.
When the specified value of the volt is applied and the steering angle sensor 84 is disconnected, the input voltage of the A0 terminal exceeds the specified value, the comparator 88 is turned on, and the input voltage of the A1 terminal is continuously at the high level H. Therefore, if the input voltage of the A1 terminal is at a high level H for a predetermined time, for example, 2 seconds, the program of the TCL 76 is determined so that disconnection is determined and the occurrence of abnormality of the steering angle sensor 84 or the steering shaft reference position sensor 86 is detected. It has been set.

In the above-described embodiment, the abnormality of the steering angle sensor 84 and the like is detected by hardware, but it is naturally possible to detect the abnormality by software.

For example, as shown in FIG. 20, which shows an example of the procedure for detecting this abnormality, the TCL 76 first operates at W1 as shown in FIG.
When the abnormality is judged by the disconnection detection shown in FIG. 9 and it is judged that there is no abnormality, the front wheel rotation sensor 66
Also, it is determined whether or not the rear wheel rotation sensors 80 and 81 are abnormal. In this step of W2, each rotation sensor 66, 8
When it is determined that there is no abnormality in 0 and 81, it is determined in W3 whether or not the steering shaft 83 has been steered one rotation or more in the same direction, for example, 400 degrees or more. In the case where the steering shaft 83 is determined in step W3 it was judged steering over 400 degrees in the same direction, whether or not there is a signal indicating the reference position [delta] _N of the steering shaft 83 from the steering shaft reference position sensor 86 at W4 Judge.

Then, in the step of W4, the steering shaft 8
If it is determined that there is no signal indicating the third reference position [delta] _N, if the steering shaft reference position sensor 86 is normal, the signal indicating the reference position [delta] _N of the steering shaft 83 is supposed there is at least once, W4 It is determined that the steering angle sensor 84 is abnormal, and the abnormality occurrence flag _FW is set.

If it is determined in step W3 that the steering shaft 83 is not steered in the same direction by 400 degrees or more,
Or when the signal indicating the reference position [delta] _N of the steering shaft 83 is determined that there from the steering shaft reference position sensor 86 at W4 step, whether done so learn the steering shaft neutral position [delta] _M at W6 That is, it is determined whether at least one of the two steering angle neutral position learned flags F _HN and F _H is set.

Then, in this W6 step, the steering shaft 83
When it is determined that the learning of the neutral position δ _M has been completed, the rear wheel speed difference | V _RL −V _RR |
The vehicle speed V exceeds 20 km / h at W8, for example 20 km / h and 6 / h.
If the absolute value of the turning angle δ _H of the steering shaft 83 at this time is less than 10 degrees, that is, if the vehicle 82 is turning at a certain speed, If the steering angle sensor 84 is functioning normally,
Since the absolute value of the turning angle δ _H should be 10 degrees or more, it is determined that the steering angle sensor 84 is abnormal at W10.

[0109] Incidentally, the slip correction amount V _KC corresponding to the target lateral acceleration G _YO is because additional steering of the steering wheel 85 by the driver can be considered, at the target lateral acceleration G _YO is a small area, the correction lateral acceleration G It is set smaller than the slip correction amount V _KC corresponding to _YF . Further, in a region where the vehicle speed V is low, it is desirable to ensure the acceleration of the vehicle 82. On the contrary, when the vehicle speed V is a certain speed or more, it is necessary to consider the ease of turning, and therefore, read from FIG. The corrected slip correction amount V _KF is calculated by reading the correction coefficient corresponding to the vehicle speed V from the map shown in FIG. 21 and multiplying it by the slip correction amount V _KC .

As a result, the target front wheel speed V _FO for calculating the correction torque decreases, the slip ratio S during turning becomes smaller than the target slip ratio S _O during straight traveling, and the vehicle 82
Although the acceleration performance of is slightly deteriorated, good turning performance is secured.

As shown in FIG. 22 showing the procedure for selecting the target lateral acceleration G _YO and the actual lateral acceleration G _Y , TCL7
Reference numeral 6 denotes a corrected lateral acceleration G from the filter unit 123 as a lateral acceleration for calculating the slip correction amount V _KC at T1.
_{Using YF} , it is determined at T2 whether or not the slip control flag F _S is set.

If it is determined in step T2 that the slip control flag F _S is set, the corrected lateral acceleration G _YF is used as it is. This is because when the lateral acceleration, which is a reference for determining the slip correction amount V _KC during the slip control, is changed from the corrected lateral acceleration G _YF to the target lateral acceleration G _YO , the slip correction amount V _KC greatly changes and the vehicle 82
Is likely to be disturbed.

If it is determined in the step T2 that the slip control flag F _S is not set, T3
At, it is determined whether or not one of the two steering angle neutral position learned flags F _HN and F _H is set. If it is determined that neither of the two steering angle neutral position learned flags F _HN and F _H has been set, the corrected lateral acceleration G _YF is employed as it is. Also, this T
If it is determined in step 3 that one of the two steering angle neutral position learned flags F _HN , F _H has been set, the lateral acceleration for calculating the slip correction amount V _KC at T4. _Is adopted as the target lateral acceleration _GYO . As a result of the above, the target front wheel speed V _FS for correction torque calculation is given by the following equation. V _FS = V _FO + V _K -V _KF

Next, the slip amount, which is the deviation between the actual front wheel speed V _F obtained from the detection signal of the front wheel rotation sensor 66 by filtering for the purpose of removing noise and the target front wheel speed V _FS for correction torque calculation. The subtractor 124 calculates s. When the slip amount s is less than or equal to a negative set value, for example, −2.5 km / h or less, the slip amount s−2.5 km / h is clipped by the clip unit 125, and the slip amount after the clipping process is performed. The proportional correction described later is performed on s to prevent over-control in the proportional correction so that output hunting does not occur.

Further, the final correction torque T _PID is calculated by performing integral correction on the slip amount s before the clipping process using an integration constant ΔT _i described later and further performing differential correction.

For the proportional correction, the multiplication unit 126 multiplies the slip amount s by the proportional coefficient K _P to obtain a basic correction amount, and the multiplication unit 127 further calculates the gear ratio ρ _{m of the} hydraulic automatic transmission 13. _Is multiplied by a preset correction coefficient ρ _KP to obtain the proportional correction torque T _P. Note that the proportional coefficient K _P
Is read from the map shown in FIG. 23 according to the slip amount s after the clipping process.

Further, in order to realize the correction corresponding to the gradual change of the slip amount s as the integral correction, a basic correction amount is calculated by the integration calculation unit 128, and the multiplication unit 129 calculates the correction amount. Gear ratio ρ of hydraulic automatic transmission 13
_The integral correction torque T _I is obtained by multiplying a predetermined correction coefficient ρ _KI based on _m . In this case, in this embodiment, a constant small integral correction torque ΔT _I is integrated, and
When the slip amount s is positive every millisecond sampling period, the small integral correction torque ΔT _I is added, and when the slip amount s is negative, the small integral correction torque ΔT _I is subtracted.

However, the integral correction torque T _I is equal to the vehicle speed V
The lower limit value T _IL as shown in the map of FIG. 24 that is variable according to the above is set, and by this clipping processing, a large integral correction torque T is set when the vehicle 82 starts, particularly when it starts uphill.
_Since the driving force of the engine 11 is ensured by operating _I and the vehicle speed V increases after the vehicle 82 starts to move, on the contrary, if the correction is too large, the stability of the control is lost, so that the integral correction torque T _I becomes small. I am trying. Further, the upper limit on the integral correction torque T _I to enhance the convergence of control, for example, set the 0Kgm, integral correction torque T _I by the clipping process changes as shown in FIG. 25.

The proportional correction torque T _P and the integral correction torque T _I calculated in this manner are added by the adder 130 to calculate the proportional-integral correction torque T _PI .

The correction coefficients ρ _KP and ρ _KI are read from a map as shown in FIG. 26 which is preset in association with the gear ratio ρ _m of the hydraulic automatic transmission 13.

Further, in the present embodiment, the differential operation section 131 calculates the rate of change G _s of the slip amount s, and the differential coefficient K _D
Is multiplied by the multiplication unit 132 to calculate a basic correction amount for a sudden change in the slip amount s. And the upper limit value and the lower limit value are respectively set for the obtained values,
As differential correction torque T _D is not an extremely large value, performs a clip processing by the clip portion 133, to obtain a differential correction torque T _D. The clip portion 133 may be momentarily idling or locked depending on the road surface conditions, the traveling state of the vehicle 82, etc., while the vehicle 82 is traveling, depending on the wheel speeds V _F , V _RL , and V _RR. In this case, the change rate G _s of the slip amount s becomes an extremely large positive or negative value, and the control may diverge, resulting in a decrease in responsiveness. For example, the lower limit value is clipped to −55 kgm and the upper limit value is 55 kgm. This is to prevent the differential correction torque T _D from taking an extremely large value.

Thereafter, the addition unit 134 adds the proportional-integral correction torque T _PI and the derivative correction torque T _D ,
The final correction torque T _PID thus obtained is subtracted from the subtractor 11.
6 is subtracted from the above-mentioned reference drive torque T _B , and the multiplier 135 is further used to multiply the engine 11 and the axles 89, 9 of the front wheels 64, 65.
By multiplying by the reciprocal of the total reduction ratio between 0 and
The target drive torque T _OS for slip control shown in equation (10) is calculated. _{T OS = (T B -T PID} ) / (ρ m · ρ d · ρ T) ... (10)

[0123] Here, ρ _d is a differential gear reduction ratio, ρ _T is a torque converter ratio, and when the hydraulic automatic transmission 13 performs an upshift speed change operation, the speed ratio ρ _m on the high speed side after the end of the speed change. Is output. That is, in the case of the upshift gear shifting operation of the hydraulic automatic transmission 13, the gear ratio ρ on the high speed stage side at the time of outputting the gear shift signal.
_{When m} is adopted, the target drive torque T _OS increases during gear shifting and the engine 11 blows up, as is apparent from the above equation (10). The target drive torque T is completed, for example, for 1.5 seconds.
The speed ratio ρ _m on the low speed side that can reduce the _OS is maintained, and the speed ratio ρ _m on the high speed side is adopted 1.5 seconds after the signal for starting the speed change is output. For the same reason, in the case of a downshift gear shifting operation of the hydraulic automatic transmission 13, the gear ratio ρ _m on the low speed stage side is immediately adopted at the time of outputting the gearshift signal.

Target drive torque T calculated by the above equation (10)
_{Since OS} should be a positive value as a matter of course, the target drive torque T _OS is clipped to 0 or more to determine the start or end of slip control in order to prevent a calculation error in the clipping unit 136. Information regarding the target drive torque T _OS is output to the ECU 15 in accordance with the determination process of the start / end determination unit 137.

The start / end determination unit 137 has the following (a) to (e)
Determines that the initiation of the slip control when satisfying all of the conditions shown in, switched so as to select the output from the low-speed selector 101 as a vehicle speed V _S for slip control with sets of slip control flag F _S The switch 103 is operated, and information on the target drive torque T _{OS is} transmitted to the ECU 1.
Output to 5, until the slip control flag F _S to determine the end of the slip control is reset, and this process is continued. (a) The driver operates a manual switch (not shown) to desire slip control. (b) The driving torque T _d requested by the driver is the minimum driving torque required to drive the vehicle 82, for example, 4 kgm.
That is all. In this embodiment, the required drive torque T
the engine speed N _E which is calculated by the detection signal from the crank angle sensor 62 _d, 27 which is set in advance on the basis of the accelerator opening theta _A calculated by the detection signal from the accelerator opening sensor 76 It is read from the map as shown. (c) The slip amount s is 2 km / h or more. (d) The rate of change G _s of the slip amount _s is 0.2 g or more. (e) The actual front wheel acceleration G _F obtained by differentiating the actual front wheel speed V _F with respect to time by the differential calculation unit 138 is 0.2 g or more.

On the other hand, when the start / end determining unit 137 determines that the slip control is started and either of the following conditions (f) and (g) is satisfied, it is determined that the slip control is completed. To reset the slip control flag F _S ,
The changeover switch 1 stops transmission of the target drive torque T _{OS to} the ECU 15 and selects the output from the high vehicle speed selection unit 102 as the vehicle speed V _S for slip control.
Activate 03. (f) The target drive torque T _OS is the required drive torque T _d or more, and the slip amount s is a constant value, for example, −2 km / h or less for a certain period of time, for example, 0.5 seconds or more. (g) The state where the idle switch 68 is changed from off to on, that is, the state where the driver releases the accelerator pedal 31 continues for a certain time, for example, 0.5 seconds or more.

The vehicle 82 is provided with a manual switch (not shown) for the driver to select the slip control. When the driver operates the manual switch to select the slip control, it will be described below. Perform slip control operation.

FIG. 2 showing the flow of this slip control process.
As shown in FIG. 8, the TCL 75 calculates the target drive torque T _OS by the detection and calculation processing of various data described above in S1, but this calculation operation is performed regardless of the operation of the manual switch.

[0129] Next, first slip control flag F _S at S2 is determines whether it is set, because the first slip control flag F _S is not set, T
The CL 76 determines in S3 whether the slip amount s of the front wheels 64 and 65 is larger than a preset threshold value, for example, 2 km / h.

When it is determined in step S3 that the slip amount s is greater than 2 km / h, the TCL 76 determines in step S4 whether the rate of change G _s of the slip amount s is greater than 0.2 g.

If it is determined in step S4 that the slip amount change rate G _s is larger than 0.2 g, the TCL 76 determines in step S5 that the driver's required drive torque T _d is the minimum required to drive the vehicle 82. It is determined whether or not the driving torque is greater than, for example, 4 kmm, that is, whether or not the driver intends to drive the vehicle 82.

At the step S5, the required drive torque T
_d is greater than 4Kmm, i.e. when the driver determines that there is intention to drive the vehicle 82, sets in the slip control flag F _S at S6, whether the slip control flag F _S is set at S7 Determine again whether or not.

If it is determined in step S7 that the slip control flag F _S is being set, the slip calculated in advance as the target drive torque T _OS of the engine 11 in equation (10) is calculated in step S8. The target drive torque T _OS for control is adopted.

When it is determined in step S7 that the slip control flag F _S has been reset, the TCL 76 outputs the maximum torque of the engine 11 as the target drive torque T _{OS in} step S9. As a result, the ECU 15 reduces the duty ratio of the torque control solenoid valves 51, 56 to the 0% side, and as a result, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 31 by the driver.

In the step S3, the front wheels 64, 65 are
When it is determined that the slip amount s of is less than 2 km / h, or the slip amount change rate G _s is determined in step S4.
When it is determined that it is smaller than 0.2 g or when the required drive torque T _d is smaller than 4 kmm in the step S5, the process directly proceeds to the step S7, and the TCL 76 is set in the step S9. Target drive torque T
The maximum torque of the engine 11 is output as _OS , and
As a result of the CU 15 reducing the duty ratio of the torque control solenoid valves 51 and 56 to the 0% side, the engine 11 generates a driving torque according to the amount of depression of the accelerator pedal 31 by the driver.

On the other hand, when it is determined in step S2 that the slip control flag F _S is set, the slip amount s of the front wheels 64, 65 is the above-mentioned threshold value of −2 km / h or less in step S10. Further, the required drive torque T _d is less than the target drive torque T _OS calculated in S1 is 0.
It is determined whether or not it continues for 5 seconds or more.

In step S10, the slip amount s is smaller than 2 km / h and the required drive torque T _d is equal to or less than the target drive torque T _OS for 0.5 seconds or more, that is, the driver is in the vehicle 82. If it is determined that the acceleration of No. 1 has not been desired, the slip control in-progress flag F _S is reset in S11, and the process proceeds to step S7.

At the step S10, the slip amount s is larger than 2 km / h, or the condition that the required drive torque T _d is less than the target drive torque T _OS has not continued for 0.5 seconds or more, that is, the driver If it is determined that the vehicle 82 is desired to be accelerated, the TCL 76 sets the idle switch 6 at S12.
8 is turned on, that is, it is determined whether the throttle valve 20 is fully closed for 0.5 seconds or more.

If it is determined in step S12 that the idle switch 68 is on, the driver has not stepped on the accelerator pedal 31, so the process proceeds to step S11 to reset the slip control flag F _S. . On the contrary, when it is determined that the idle switch 68 is off, the driver depresses the accelerator pedal 31, so the process proceeds to step S7 again.

When the driver does not operate the manual switch for selecting the slip control, the TCL 76 calculates the target drive torque T _OS for slip control as described above and then executes the turning control. The target drive torque of the engine 11 is calculated.

[0141] Incidentally, the lateral acceleration G _Y is the rear wheel speed difference of the vehicle 82 | V _RL -V _RR | the utilizing (9) can be actually calculated by equation, a steering shaft turning angle [delta] _H By using it, it becomes possible to predict the value of the lateral acceleration G _Y acting on the vehicle 82, which has an advantage that quick control can be performed.

Therefore, when controlling the turning of the vehicle 82,
The TCL 76 determines the vehicle 8 based on the steering shaft turning angle δ _H and the vehicle speed V.
2 of the target lateral acceleration G _YO is calculated by the equation (3), based on the vehicle longitudinal acceleration as the vehicle 82 is not an extreme under-steering, that is, the target longitudinal acceleration G _XO in the target lateral acceleration G _YO Set. However, the stability factor A in equation (3) is set based on the estimated road surface μ. Then, a target drive torque T _OC of the engine 11 corresponding to the target longitudinal acceleration G _XO is calculated.

FIG. 2 showing a calculation block of this turning control.
9. As shown in FIG. 30, the TCL 76 includes a vehicle speed calculation unit 14
At 0, the vehicle speed V is calculated from the output of the pair of rear wheel rotation sensors 80 and 81 by the above equation (1), and the steering angle sensor 84 is calculated.
The steering angle δ of the front wheels 64, 65 is calculated from the equation (2) based on the detection signal from the vehicle, and the target lateral acceleration calculation unit 141 is used by the target lateral acceleration calculation unit 141 using the stability factor A set by the road surface μ. The target lateral acceleration G _{YO of} is calculated from the equation (3). In this case, the region where the vehicle speed V is low, for example, 2
When the distance is 3 km or less, it is better to prohibit the turning control than to perform the turning control, because sufficient acceleration can be obtained when turning left or right at an intersection with heavy traffic, etc. In this embodiment, the correction coefficient multiplication unit 1
At 42, the target lateral acceleration G _YO is multiplied by the correction coefficient K _Y as shown in FIG. 31 according to the vehicle speed V.

By the way, in the state where the learning of the steering shaft neutral position δ _M is not performed, there is a problem in reliability in calculating the target lateral acceleration G _YO based on the steering angle δ from the viewpoint of reliability. It is desirable not to start the turning control until the steering shaft neutral position δ _M is learned. However, the vehicle 82
In the case where the vehicle 82 travels on a curved road immediately after the start of traveling, the vehicle 82 needs a turning control, but the turning control is not started because the learning start condition of the steering shaft neutral position δ _M is not satisfied easily. There is a risk of malfunction.
Therefore, in this embodiment, until the steering shaft neutral position δ _M is learned, the changeover switch 143 is used to perform the turning control by using the corrected lateral acceleration G _YF from the filter unit 123 based on the equation (5). There is. That is, in a state in which both of the two steering angle neutral position learned flags F _HN and F _H are reset, the corrected lateral acceleration G _YF is adopted by the changeover switch 143, and the two steering angle neutral position learned flags F are used. _HN, if at least one of the F _H is set, the correction coefficient multiplication unit 1 by switching switches 143
The target lateral acceleration G _YO from 42 is selected.

The stability factor A described above is
As is well known, the value is determined by the configuration of the suspension system of the vehicle 82, the characteristics of the tires, the road surface condition, and the like. Specifically, the actual lateral acceleration G _Y generated in the vehicle 82 during a steady circular turn and the steering angle ratio δ _H / δ of the steering shaft 83 at this time are shown.
_HO (lateral acceleration G based on neutral position δ _M of steering shaft 83)
The turning angle δ _H of the steering shaft 83 during acceleration with respect to the turning angle δ _HO of the steering shaft 83 in an extremely low-speed running state where _Y is _close to 0.
The ratio is expressed as the slope of the tangent line in the graph as shown in FIG. That is, in a region where the lateral acceleration G _Y is small and the vehicle speed V is not too high, the stability factor A has a substantially constant value (A = 0.002), but when the lateral acceleration G _Y exceeds 0.6 g. The stability factor A rapidly increases, and the vehicle 82 exhibits an extremely strong understeering tendency.

Therefore, in this embodiment, the stability factor setting means 141A is the road surface μ estimating means 113A (see FIG. 1).
0) is used to read and set the stability factor A from the map shown by Y3 in FIG. 45, and using this value, the target lateral acceleration calculation unit 141 uses the target lateral acceleration calculation unit 141 to calculate the target lateral acceleration. The acceleration G _YO is calculated. In the map shown in FIG. 45, the stability factor A is increased stepwise as the road surface μ decreases, but it may be increased continuously.

In addition, when the stability factor A is set to a fixed value of 0.002 based on FIG. 32 corresponding to a dry paved road surface (hereinafter referred to as a high μ road),
The target lateral acceleration G _{YO of the} vehicle 82 calculated by the equation (3) is
The drive torque of the engine 11 may be controlled so as to be less than 0.6 g. Further, in the case of a slippery road surface such as an icy road (hereinafter referred to as a low μ road), the stability factor A may be set to a fixed value of about 0.005. In this case, since the target lateral acceleration G _YO has a larger value than the actual lateral acceleration G _Y on a low μ road, the target lateral acceleration G _YO is larger than a preset threshold value, for example (G _YF -2). Whether or not,
When the target lateral acceleration G _YO is larger than this threshold value, it is determined that the vehicle 82 is traveling on a low μ road, and turning control for the low μ road may be performed as necessary. Specifically, the above
0.05 g for corrected lateral acceleration G _YF calculated based on equation (9).
Target lateral acceleration G whether _YO is greater than a predetermined threshold value by adding, that since the direction of the target lateral acceleration G _YO than the actual lateral acceleration G _Y is a low μ road is a large value, the target lateral It is determined whether the acceleration G _YO is greater than this threshold value, and if the target lateral acceleration G _YO is greater than the threshold value, it is determined that the vehicle 82 is traveling on a low μ road.

When the target lateral acceleration G _YO is calculated in this way, the magnitude of the target lateral acceleration G _YO and the vehicle speed V are calculated in advance.
The target longitudinal acceleration G _XO of the vehicle 82 set in accordance with the above is read from the map as shown in FIG. 33 stored in the TCL 76 in advance by the target longitudinal acceleration calculation unit 144, and the engine 11 corresponding to this target longitudinal acceleration G _XO is read. Reference drive torque T of
_B is calculated by the reference drive torque calculation unit 145 by the following equation (11). T _B = (G _XO · W _b · r + T _L + T _C ) / (ρ _m · ρ _d · ρ _T ) ... (11) where T _L is the road surface resistance obtained as a function of the lateral acceleration G _Y of the vehicle 82. Which is the road-load torque, which is obtained from the map as shown in FIG. 34 in this embodiment. Further, T _C is a cornering drag correction torque obtained as a function of the lateral acceleration G _Y of the vehicle 82 or the steering shaft turning angle δ _H , and like the case of the slip control in FIGS. 10 and 11, the cornering drag correction amount calculation unit 1
45A reads a coefficient corresponding to the road surface μ estimated by the road surface μ estimating means 113A from the map, multiplies the coefficient by the cornering drag correction amount read from the map as a function of the steering shaft turning angle δ _H , and the obtained value is obtained. It is given to the reference drive torque calculation unit 145 as T _C.

Here, the driver's will is not reflected at all by merely obtaining the target drive torque of the engine 11 from the steering shaft turning angle δ _H and the vehicle speed V, and the driver is in controllability of the vehicle 82. There may be dissatisfaction. Therefore, it calculated required driving torque T _d of the engine 11 that the driver wants the depression amount of the accelerator pedal 31, the required driving torque T _d
It is desirable to set the target drive torque of the engine 11 in consideration of the above.

Therefore, in the present embodiment, the reference drive torque T _B
In order to determine the adoption ratio, the reference drive torque T _B is multiplied by the weighting coefficient α in the multiplication unit 146 to obtain the corrected reference drive torque. The weighting coefficient α is set empirically by turning the vehicle 82. Assuming a high μ road 0.
Although a fixed value around 6 may be adopted, in the present embodiment, the coefficient α is continuously changed according to the road surface μ estimated by the road surface μ estimating means 113A. That is, the α calculation unit 146A
46 is a map of the road surface μ and the coefficient α as shown by Y14 in FIG. 46, and when the estimated road surface μ is input, this road surface μ
Is read and set, and the multiplication unit 146,
Give to 147. In the map shown, α = for high μ
In the case of 0.3 and low μ, α = 0.6, and in the middle, the road surface μ
As α decreases, α increases from 0.3 to 0.6.

On the other hand, based on the engine speed N _E detected by the crank angle sensor 55 and the accelerator opening θ _A detected by the accelerator opening sensor 77, the required drive torque T _d desired by the driver is shown in the above figure. 33, and the multiplication requesting torque is calculated by the multiplying unit 147 as the required driving torque T _d (1
−α). For example, α = 0.
When set to 6, the adoption ratio of the reference drive torque T _B and the required drive torque T _d is 6: 4. Therefore, the target drive torque T _OC of the engine 11 is calculated by the addition unit 148 as follows (12)
It is calculated by a formula.

T _OC = α · T _B + (1-α) · T _d (12)

By the way, when the increase / decrease amount of the target drive torque T _OC of the engine 11 set every 15 milliseconds is very large, a shock is generated due to the acceleration / deceleration of the vehicle 82, and the riding comfort is deteriorated. Therefore, when the increase / decrease amount of the target drive torque T _OC of the engine 11 becomes so large that the riding comfort of the vehicle 82 is deteriorated, it is desirable to regulate the increase / decrease amount of the target drive torque T _OC .

Therefore, in this embodiment, the change amount clip section 1 is used.
49, the absolute value | ΔT of the difference between the target drive torque T _{OC (n)} calculated this time and the target drive torque T _{OC (n-1)} calculated last time.
Is smaller than the increase / decrease allowable amount T _K , the calculated target drive torque T _{OC (n)} is used as it is.
The difference ΔT between the currently calculated target drive torque T _{OC (n)} and the previously calculated target drive torque T _{OC (n-1)} is a negative increase / decrease allowable amount T.
If it is not larger than _K , this target drive torque T
Set _{OC (n)} by the following formula. T _{OC (n)} = T _{OC (n−1)} −T _{K In other} words, the reduction in the target drive torque T _{OC (n−1)} calculated last time is regulated by the increase / decrease allowable amount T _K , and the drive torque of the engine 11 is reduced. Decrease the deceleration shock associated with If the difference ΔT between the currently calculated target drive torque T _{OC (n)} and the previously calculated target drive torque T _{OC (n-1)} is equal to or greater than the allowable increase / decrease amount T _K , the current target drive torque T _{OC (n)} is set by the following equation. T _{OC (n)} = T _{OC (n-1)} + T _K That is, the difference ΔT between the target drive torque T _{OC (n)} calculated this time and the target drive torque T _{OC (n-1)} calculated last time is the increase / decrease allowable amount. When T _K is exceeded, the increase range for the target drive torque T _{OC (n-1)} calculated last time is restricted by the increase / decrease allowable amount T _K ,
The acceleration shock due to the increase in the drive torque of the engine 11 is reduced.

Then, according to the determination processing in the start / end determining section 150 for determining the start or end of the turning control, the information regarding the target drive torque T _OC is obtained from the ECU 15.
Is output to

The start / end determination section 150 is provided with the following (a)-
When all the conditions shown in (d) are satisfied, it is determined that the turning control is started, the turning control in-progress flag F _C is set, and information on the target drive torque T _OC is output to the ECU 15.
This process is continued until it is determined that the turning control is finished and the turning control flag F _C is reset. (a) The target drive torque T _OC is less than a value obtained by subtracting a threshold value, for example, 2 kgm from the required drive torque T _d . (b) The driver operates a manual switch (not shown) to request turning control. (c) The idle switch 68 is off. (d) The control system for turning is normal.

On the other hand, when the start / end determining unit 150 determines that the turning control is started and either of the following conditions (e) and (f) is satisfied, it is determined that the turning control is finished. Then, the turning control flag F _C is reset, and the ECU 15
The transmission of the target drive torque T _OC for is stopped. (e) The target drive torque T _OS is _{equal to} or greater than the required drive torque T _d . (f) The control system for turning has an abnormality such as failure or disconnection.

By the way, as a matter of course, there is a constant proportional relationship between the output voltage of the accelerator opening sensor 77 and the accelerator opening θ _{A. When} the accelerator opening θ _A is fully closed, The accelerator opening sensor 77 is attached to the throttle body 21 so that the output voltage of the sensor 77 is, for example, 0.6 volt. However, when the accelerator opening sensor 77 is removed from the throttle body 21 for inspection and maintenance of the vehicle 82, and then reassembled, it is substantially impossible to accurately return the accelerator opening sensor 77 to the original attached state. It is possible, and the position of the accelerator opening sensor 77 with respect to the throttle body 21 may be shifted due to aging or the like.

Therefore, in this embodiment, the fully closed position of the accelerator opening sensor 77 is learned and corrected, whereby the accelerator opening θ _A calculated based on the detection signal from the accelerator opening sensor 77 is calculated. The reliability is secured.

As shown in FIG. 35, which shows the procedure for learning the fully closed position of the accelerator opening sensor 77, after the idle switch 68 is turned on and the ignition key switch 75 is turned from on to off, for a certain period of time, for example, The output of the accelerator opening sensor 77 for 2 seconds is monitored, and the minimum value of the output of the accelerator opening sensor 77 during this period is set to the accelerator opening θ.
_A is taken in as the fully closed position of _A , stored in a backup RAM (not shown) incorporated in the ECU 15,
Correcting the accelerator opening theta _A reference to the minimum value of the output of the accelerator opening sensor 77 until the next learning.

However, when the storage battery (not shown) mounted on the vehicle 82 is removed, the memory of the RAM is erased. In such a case, the learning procedure shown in FIGS. 36 and 37 is adopted. .

That is, the TCL 76 determines whether or not the fully closed value θ _AC of the accelerator opening θ _A is stored in the RAM at A1, and the accelerator opening θ _A at this step A1.
If it is determined that the fully closed value θ _AC is not stored in the RAM, the initial value θ _{A (0)} is stored in the RAM at A2.

On the other hand, if it is determined in step A1 that the fully closed value θ _AC of the accelerator opening θ _A is stored in the RAM, the ignition key switch 75 is pressed in A3.
It is determined whether or not is turned on. If it is determined in step A3 that the ignition key switch 75 has changed from the ON state to the OFF state, the count of a learning timer (not shown) is started in A4. And
After the start of the counting of the learning timer, it is determined at A5 whether or not the idle switch 68 is on.

If it is determined in step A5 that the idle switch 68 is in the off state, it is determined in step A6 whether or not the count of the learning timer has reached a set value, for example, 2 seconds. Return to step A5. or,
If it is determined in step A5 that the idle switch 68 is on, the output of the accelerator opening sensor 77 is read at a predetermined cycle in A7, and the current accelerator opening θ _{A (n)} is read in A8. It is equal to or smaller than the minimum value theta _AL accelerator opening theta _a far.

[0165] Here, when it is determined that the accelerator opening degree this time θ _{A (n)} is greater than the minimum value theta _AL accelerator opening theta _A to date, the minimum accelerator opening theta _A far Value θ _AL
If the current accelerator opening θ _{A (n)} is determined to be smaller than the minimum value θ _{AL of the} previous accelerator opening θ _A , the current accelerator opening θ _A is determined at A9. update _a and _(n) as a new minimum value theta _AL. This operation is repeated in step A6 until the count of the learning timer reaches a set value, for example, 2 seconds.

When the count of the learning timer reaches the set value, the minimum value θ _AL of the accelerator opening θ _A at A10 is a preset clip value, for example, between 0.3 volt and 0.9 volt. Or not. When it is determined that the minimum value θ _AL of the accelerator opening θ _A is within the preset clip value range, the initial value θ _{A (0) of the} accelerator opening θ _A or all of _A fully closed value θ _{AC (n)} of the accelerator opening θ _{A obtained} by learning this time when the closed value θ _AC is brought closer to a fixed value in the direction of the minimum value θ _AL , for example, by 0.1 volt.
And In other words, the initial value θ _{A (0)} of the accelerator opening theta _A or when the total closed value theta _AC is greater than its minimum value theta _{AL is, θ AC (n) = θ} AC (0) -0.1 or , Θ _{AC (n)} = θ _{AC (n-1)} −0.1, on the contrary, the initial value θ _{A (0)} of the accelerator opening θ _A or the fully closed value θ _AC is smaller than its minimum value θ _AL . Is also large, θ
Set _{AC (n)} = θ _{AC (0)} +0.1 or θ _{AC (n)} = θ _{AC (n-1)} +0.1.

At the step A10, the accelerator opening θ
_When it is determined that the minimum value θ _{AL of A} is out of the preset clip value range, the clip value of the one that is out of A 12 is replaced as the minimum value θ _AL of the accelerator opening θ _A , and In step A11, the fully closed value θ _AC of the accelerator opening θ _A is learned and corrected.

As described above, the minimum value θ of the accelerator opening θ _A
By setting the upper limit value and the lower limit value to _AL, there is no risk of erroneous learning even when the accelerator opening sensor 77 fails, and by setting the learning correction amount per time to a constant value, noise Erroneous learning is not performed even for disturbances such as

In the above-described embodiment, the learning start timing of the fully closed value θ _AC of the accelerator opening sensor 77 is based on the time when the ignition key switch 75 changes from the ON state to the OFF state, but it is incorporated in a seat (not shown). The seating sensor is used to detect that the driver has left the seat even when the ignition key switch 75 is in the on state by using the seat pressure change, the position displacement, and the like by the seating sensor, and the learning processing after the step A4. May be started.
When the door lock device (not shown) is operated from outside the vehicle 82 or the key entry system detects that the door lock device is operated, the fully closed value of the accelerator opening sensor 77 is detected. It is also possible to start learning of θ _AC . In addition, the position of the shift lever (not shown) of the hydraulic automatic transmission 13 is the neutral position or the parking position (in the case of a vehicle equipped with a manual transmission, the neutral position), the manual brake is operated, and The air conditioner is off,
That is, the learning process may be performed when the idle-up state is not set.

The vehicle 82 is provided with a manual switch (not shown) for the driver to select the turning control. When the driver operates the manual switch to select the turning control, it will be described below. The operation of turning control is performed.

As shown in FIGS. 38 and 39 showing the control flow for determining the target drive torque T _OC for the turning control, the target drive torque is detected by the above-described various data detection and calculation processing in C1. Although T _OC is calculated, this operation is performed regardless of the operation of the manual switch.

Next, at C2, it is determined whether the vehicle 82 is under turning control, that is, whether the turning control flag F _C is set. Since the turning control is not being performed at first, it is determined that the turning control flag F _C is in the reset state, and it is determined whether C3 is, for example, (T _d -2) or less.
That is, the target drive torque T _OC can be calculated even when the vehicle 82 is traveling straight, but the value is usually larger than the driver's required drive torque _Td . However, since the required drive torque _Td generally decreases when the vehicle 82 turns, the time when the target drive torque _TOC becomes equal to or less than the threshold value ( _Td- 2) is determined as the start condition of the turn control. ing.

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

When it is determined in step C3 that the target drive torque T _OC is less than or equal to the threshold value (T _d -2), TCL76
Determines at C4 whether the idle switch 68 is off.

When it is determined in step C4 that the idle switch 68 is off, that is, the accelerator pedal 31 is depressed by the driver, the turning control flag F _C is set in C5. Next, at C6, it is determined whether or not at least one of the two steering angle neutral position learned flags F _HN and F _H is set, that is, the steering angle sensor 84.
The authenticity of the detected steering angle δ is determined.

When it is determined in step C6 that at least one of the two steering angle neutral position learned flags F _HN and F _H has been set, in step C7 the turning control flag F _{C is set.}
It is again determined whether or not is set.

[0177] In the above procedure, because the turning control flag F _C is set at C5 of the step, turning control flag F _C is a step of C7 is judged to be set, the previous at C8 The calculated value, that is, the target drive torque T _{OC in} the step C1 is used as it is.

On the other hand, if it is determined that the steering angle neutral position learned flag F _H is not set in the step C6, the steering angle δ calculated by the equation 2 is not credible. ) _Does not adopt the target drive torque T _OC calculated in
The TCL 76 outputs the maximum torque of the engine 11 at C9 as the target drive torque T _OC , whereby the ECU 15 reduces the duty ratio of the torque control solenoid valves 51 and 56 to the 0% side. A drive torque corresponding to the amount of depression of the accelerator pedal 31 is generated.

If it is determined in step C3 that the target drive torque T _OC is not equal to or less than the threshold value (T _d -2), the control is not shifted to the turning control and the process from step C6 or C7 to C9 is performed.
The TCL 76 determines the target drive torque T _OC
The maximum torque of the engine 11 is output as
As a result of U15 lowering the duty ratio of the torque control solenoid valves 51, 56 to the 0% side, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 31 by the driver.

Similarly, when it is determined in step C4 that the idle switch 68 is on, that is, the accelerator pedal 31 is not depressed by the driver, the TC
L76 outputs the maximum torque of the engine 11 as the target drive torque T _OC , whereby the ECU 15 reduces the duty ratio of the torque control solenoid valves 51 and 56 to the 0% side. The drive torque is generated in accordance with the amount of depression of the vehicle, and the process does not shift to the turning control.

If it is determined in step C2 that the turning control flag F _C is set, the target drive torque T _OC calculated this time and the target drive torque T _{OC (n- It} is determined whether the difference ΔT from ₁₎ is larger than a preset increase / decrease allowable amount T _K. This increase / decrease allowable amount T _K is a torque change amount that does not cause an occupant to feel an acceleration / deceleration shock of the vehicle 82. For example, when it is desired to suppress the target longitudinal acceleration G _XO of the vehicle 82 to 0.1 g per second, the above (1
Using the equation (1), T _K = 0.1 · {(W _b · r) / (ρ _m · ρ _d · ρ _T )} · Δt.

In step C10, the target drive torque T _OC calculated this time and the target drive torque T calculated last time are calculated.
_{When it} is determined that the difference ΔT with _{OC (n-1)} is not larger than the preset increase / decrease allowable amount T _{K, the} target drive torque T _OC and the previously calculated target drive torque T _{OC (n -1)}
It is determined whether the difference ΔT from the difference ΔT is larger than the negative increase / decrease allowable amount T _K.

At step C11, the target drive torque T _OC calculated this time and the target drive torque T _{OC (n-1)} calculated last time are calculated.
When it is determined that the difference ΔT between the target drive torque T _{OC (n)} calculated this time and the target drive torque T _{OC (n-1)} calculated last time is larger than the negative allowable increase / decrease amount T _K , the absolute value of the difference │ΔT ｜
Is smaller than the increase / decrease allowable amount T _K , the calculated target drive torque T _OC of this time is directly used as the calculated value in the step C8.

Further, in step C11, the target drive torque T _OC calculated this time and the target drive torque T calculated last time are calculated.
_If it is determined that the difference ΔT from _{OC (n−1)} is not greater than the negative increase / decrease allowable amount T _K , the current target drive torque T
_OC is corrected by the following formula, and this is adopted as the calculated value in the step of C8. T _OC = T _{OC (n−1)} −T _{K In other} words, the reduction width with respect to the previously calculated target drive torque T _{OC (n−1)} is regulated by the increase / decrease allowable amount T _K , and the deceleration accompanying the reduction of the drive torque of the engine 11. It reduces shock.

[0185] On the other hand, it is determined that the difference ΔT between the target drive torque currently calculated at C10 in Step T _OC and the target driving torque T _OC previously calculated _(n-1) is increased or decreased tolerance T _K or higher Then, in C13, the target drive torque T _OC of this time is corrected by the following formula, and this is adopted as the calculated value in the step of C8. T _OC = T _{OC (n-1)} + T _K That is, also in the case of increasing the drive torque, the target drive torque T _OC calculated this time and the target drive torque T _{OC (} If _{the n-1)} difference between ΔT exceeds the decrease tolerance T _K restricts gains at decreasing tolerance T _K for the target driving torque T _OC previously calculated _(n-1), the driving of the engine 11 The acceleration shock accompanying the torque increase is reduced.

When the target drive torque T _OC is set as described above, the TCL 76 determines in C14 whether or not the target drive torque T _OC is larger than the driver's required drive torque T _d .

Here, when the turning control in-progress flag F _C is set, the target drive torque T _OC is not larger than the drive torque T _d requested by the driver, so at C15 whether the idle switch 68 is in the ON state or not. To determine.

If it is determined in step C15 that the idle switch 68 is not in the on state, it means that the turning control is required, and therefore the process proceeds to step C6.

If it is determined in step C14 that the target drive torque T _OC is larger than the driver's required drive torque T _d , it means that the turning traveling of the vehicle 82 has ended. Then, the turning control flag F _C is reset. Similarly, if it is determined in step C15 that the idle switch 68 is on,
Since the accelerator pedal 31 is not depressed, the process proceeds to step C16 and the turning control flag F _C
Reset.

When the turning control flag F _C is reset at C16, the TCL 76 outputs the maximum torque of the engine 11 as the target drive torque T _OC at C9, whereby the ECU 15 causes the torque control solenoid valve 51, As a result of reducing the duty ratio of 56 to the 0% side, the engine 11 generates a driving torque according to the amount of depression of the accelerator pedal 31 by the driver.

Incidentally, in order to simplify the procedure of the above-described turning control, it is of course possible to ignore the drive torque T _d requested by the driver. In this case, the target drive torque is calculated by the equation (11). It suffices to adopt a possible reference drive torque T _B. Even when the driver's required drive torque T _d is taken into consideration as in the present embodiment, the weighting coefficient α is gradually decreased with the lapse of time after the start of control, or is gradually decreased according to the vehicle speed V. Driving torque required by driver T _d
The adoption ratio of may be gradually increased. Similarly, the value of the coefficient α is kept constant for a while after the control is started, and is gradually decreased after a predetermined time elapses, or the value of the coefficient α is increased with an increase in the steering shaft turning amount δ _H. It is also possible to drive the vehicle 82 safely in a turning circuit in which the radius of curvature is gradually reduced.

[0192] In the above-described arithmetic processing method, in order to prevent the deceleration shock due to variations in the rapid driving torque of the engine 11, the target driving torque T _OC by decreasing tolerance T _K when calculating the target driving torque T _OC Although the regulation is intended, this regulation may be applied to the target longitudinal acceleration G _XO .

After calculating the target drive torque T _OC for the turning control, the TCL 76 selects the optimum final target drive torque T _O from these two target drive torques T _OS and T _OC , and outputs this to the ECU 15. . In this case, the vehicle 82
In consideration of the driving safety of, the target drive torque with a smaller value is given priority and output. However, in general, since the target drive torque T _OS for slip control is always smaller than the target drive torque T _OC for swing control, the final target drive torque T _O should be selected in order for slip control and swing control. Good.

As shown in FIG. 40 showing the flow of this processing, after calculating the target drive torque T _OS for slip control and the target drive torque T _OC for turn control in M11, M1 is calculated.
During slip control flag at 2 F _S it is determined whether it is set, if the slip control flag F _S is determined to have been set, the final target driving torque T _O
The target drive torque T _OS for slip control is selected at M13 and is output to the ECU 15.

On the other hand, if it is judged in the step M12 that the slip control flag F _S is not set, it is judged in M14 whether the turning control flag F _C is set or not. When it is determined that the control flag F _C is set, the final target drive torque T _O
The target drive torque T _OC for turning control is selected by M15, and this is output to the ECU 15.

If it is determined in step M14 that the turning control flag F _C is not set, then T
The CL 76 outputs the maximum torque of the engine 11 as the final target drive torque T _O to the ECU 15 at M16.

As described above, the final target drive torque T _O
On the other hand, if the output of the engine 111 cannot be reduced even by operating the throttle valve 20 via the actuator 41, or if the road surface suddenly changes from a normal dry road to a frozen road, the TCL 76 causes the ECU 15 to select The ignition timing P is set to a retard ratio with respect to the basic retard amount p _B , and this is output to the ECU 15.

The basic retard angle amount p _B is the maximum value of the retard angle that does not hinder the operation of the engine 11, and is set based on the intake air amount of the engine 11 and the engine speed N _E. However, basically, the retardation rate is selected such that the retardation amount becomes larger as the change rate G _s of the slip amount s increases. In this embodiment, the basic retardation amount p _B is used as the retardation ratio.
A 0 level to 0, and I level to compress the basic retard amount p _B two-thirds, directly outputs the basic retard amount p _B
And II levels, four is set in a fully closed operation to III levels throttle valve 20 while it outputs the base retardation amount p _B. That is, the fully closing operation of the throttle valve 20 at the III level corresponds to the portion of the present invention, and by combining it with the retarding operation described above, the engine 1 can be operated very quickly.
It is possible to reduce the drive torque of No. 1 and converge the slip of the front wheels 64 and 65.

FIG. 4 showing the procedure for reading out this retard angle ratio.
1. As shown in FIG. 42, the TCL 76 first resets the ignition timing control flag F _p at P1 and determines at P2 whether or not the slip control flag F _S is set. In the step P2, the slip control flag F _{S is set.}
If it is determined that is set, the ignition timing control flag F _p is set at P3, and it is determined at P4 whether the slip amount s is larger than 0 km / h. If it is determined in step P2 that the slip control flag F _S is not set, the process proceeds to step P4.

In step P4, the slip amount s is 0 per hour.
If it is less than km, that is, if it is determined that there is no problem even if the driving torque of the engine 11 is increased, the retard ratio is set to 0 level in P5, and this is output to the ECU 15. On the contrary, if it is determined in step P4 that the slip amount s exceeds 0 km / h, it is determined in step P6 whether the slip amount change rate G _S exceeds 2.5 G, and it exceeds 2.5 G. If you judge that P7
At, it is determined whether the target drive torque T _OS for slip control is 4 kgfm or less. If it is determined in P7 that the target drive torque T _OS for slip control is 4 kgfm or less, it is determined in P8 whether gear shifting is in progress, and if it is determined in P8 that gear shifting is in progress, P
The retard ratio is set to the II level at 9 and the retard ratio is set to the III level at P10 when it is determined that the gear change is not in progress at P8.

At step P6, the slip amount change rate G _S is
Slip amount change rate G _S in case P11 it is judged not exceed 2.5G determines whether exceeds 0.5G. P11
When it is determined that the slip amount change rate G _S exceeds 0.5 G, the target drive torque T _OS for slip control is 1 in P12.
When it is determined whether it is less than 0 kgfm, when it is determined that it is less than 10 kgfm in P12, the retard rate is set to the II level in P13, and when it is determined that it is not less than 10 kgfm in P12, the retard rate in P14 To the I level.

In step P11, the slip amount change rate G _S
When it is judged that the slip amount change rate G _S does not exceed 0.5 G, it is determined at P15 whether or not the slip amount change rate G _S exceeds 0.3 G. P
If it is determined in 15 that the slip amount change rate G _S exceeds 0.3 G, the retard ratio is set to the I level in P16, and P
If it is determined that the value does not exceed 0.3G in 15, the retard ratio is set to 0 level in P17.

When it is determined in step P7 that the target drive torque T _OS for slip control exceeds 4 kgfm, it is determined in step P18 whether the target drive torque T _OS for slip control is smaller than 10 kgfm. If it is determined in P18 that the target drive torque T _OS for slip control is smaller than 10 kgfm, P
Set the retard ratio to II level at 19 and set 1 at P18.
If it is determined that it is not smaller than 0 kgfm, the retard ratio is set to the I level at P20.

Therefore, the target drive torque T for slip control is
The retard amount of the ignition timing of the engine 11 gradually decreases as the _OS increases. Therefore, even if the ignition timing is retarded when the output of the engine 11 is large, the output of the engine 11 does not drop significantly.

Steps P9, P10, P13, P14,
P16, P17, P19, and P20 are set to the respective retard angle ratios to control the output of the engine 11, and then P21.
Check whether or not the retard ratio is III level. P
When it is judged that the retard ratio is at the III level in 21, P2
In step 2, it is determined whether the slip amount s is less than 0 km / h. If it is determined that the slip amount s is less than 0 km / h, the retard ratio is set to 0 level in P23.

At step P22, the slip amount s is 0 per hour.
When it is determined that the slip amount s is not less than 8 km, it is determined in P24 whether the slip amount s is less than 8 km / h. When it is determined that the slip amount s is less than 8 km / hr in P24, it is determined in P25 whether the slip amount change rate G _S is less than 0 G, and when it is determined that it is less than 0 G, the retard ratio is set to 0 level in P26. set. If it is determined in P24 that the slip amount s is not less than 8 km / h, and in P25 that the slip amount change rate G _S is not less than 0 G, the retard ratio is continued at the III level.

If it is determined in step P21 that the retard ratio is not at the III level, it is determined at P27 whether the retard ratio is at the II level. When it is judged at P27 that the retard ratio is at the II level, the slip amount s becomes 0 per hour at P28.
When it is determined that the slip amount s is less than 0 km / h, the retard ratio is set to 0 level in P29.

In step P28, the slip amount s is 0 per hour.
If it is judged that it is not less than km, the slip amount s is set at
Is less than 8 km / h. If the slip amount s is less than 8 km / hr in P30, it is determined in P31 whether the slip amount change rate G _S is less than 0 G, and if it is less than 0 G, the retard ratio is set to 0 level in P32. set. When it is determined in P30 that the slip amount s is not less than 8 km / h, and in P31, the slip amount change rate G _S is 0.
If it is determined that it is not less than G, the retard rate is continued at the II level.

If it is determined in step P27 that the retard ratio is not at the II level, it is determined at P33 whether the retard ratio is at the I level. When it is determined that the retard ratio is at the I level in P33, the slip amount s is 0 km / hour in P34.
If it is determined that the slip amount s is less than 0 km / hour, the retard ratio is set to 0 level in P35.

In step P34, the slip amount s is 0 per hour.
When it is judged that the distance is not less than km, the slip amount s is set in P36
Is less than 5 km / h. When it is determined that the slip amount s is less than 5 km / hour in P36, it is determined in P37 whether the slip amount change rate G _S is less than 0 G, and when it is determined that it is less than 0 G, the retard ratio is set to 0 level in P38. set. When it is determined in P36 that the slip amount s is not less than 5 km / h, and in P37, the slip amount change rate G _S is 0.
If it is determined that it is not less than G, the retard ratio is continued at the I level.

The ECU 15 determines the ignition timing P and the basic ignition timing P from a map (not shown) relating to the ignition timing P and the basic retardation amount p _B which are preset based on the engine speed N _E and the intake air amount of the engine 11. The retard amount p _B is read based on the detection signal from the crank angle sensor 62 and the detection signal from the air flow sensor 70, and is corrected based on the retard ratio sent from the TCL 76 to obtain the target retard amount p _O.
Is calculated. In this case, the upper limit value of the target retardation amount p _O is set corresponding to the upper limit temperature of the exhaust gas that does not damage the exhaust gas purification catalyst (not shown), and the temperature of this exhaust gas is measured by the exhaust temperature sensor 74. It is detected by the detection signal.

If the cooling water temperature of the engine 11 detected by the water temperature sensor 71 is lower than a preset value, retarding the ignition timing P may cause knocking or stall of the engine 11. Therefore, the retarding operation of the ignition timing P shown below is stopped.

As shown in FIGS. 43 and 44 showing the calculation procedure of the target retardation amount p _O in this retardation control, as shown in FIGS.
U15 determines whether the slip control flag F _S described above in Q1 is set, when the slip control flag F _S is determined to be set, retarding the rate at Q2 is a III level It is determined whether or not it has been set.

When it is judged in the step of Q2 that the retard ratio is the III level, the basic retard amount p _B read from the map in Q3 is used as it is as the target retard amount p _O. , The ignition timing P is retarded by the target retardation amount p _O. Further, the duty ratio of the torque control solenoid valves 51 and 56 is set to 100% in Q4 so that the throttle valve 20 is fully closed regardless of the value of the final target drive torque T _O.
To forcibly realize the fully closed state of the throttle valve 20. Thus, even if the slip rate of change G _s is increasing rapidly, it is possible to stifle efficiently the occurrence of slip in its early stages.

If it is determined in step Q2 that the retard rate is not III level, the retard rate is changed in Q5.
Determine whether or not it is set to the II level. And
If it is determined in step Q5 that the retardation ratio is at the II level, the basic retardation amount p _B obtained by reading the target retardation amount p _O from the map in step Q6, as in step Q3.
Is used as it is as the target retardation amount p _O , and the ignition timing P is retarded by the target retardation amount p _O. Further, in Q7, the ECU 1
5 sets the duty ratio of the torque control solenoid valves 51 and 56 in accordance with the value of the target drive torque T _OS by Q7, regardless of the amount of depression of the accelerator pedal 31 by the driver.
The drive torque of the engine 11 is reduced.

Here, the ECU 15 stores a map for obtaining the throttle opening θ _T using the engine speed N _E and the drive torque of the engine 11 as parameters.
15 is a target throttle opening θ corresponding to the current engine speed _NE and the target drive torque T _OS using this map.
_{Read TO} .

Next, the ECU 15 obtains the deviation between this target throttle opening θ _TO and the actual throttle opening θ _T output from the throttle opening sensor 67, and calculates the duty ratio of the pair of torque control solenoid valves 51, 56. Is set to a value commensurate with the deviation, and a current is supplied to the solenoids of the plungers 52 and 57 of the torque control solenoid valves 51 and 56, and the actual throttle opening θ _T is changed to the target throttle opening θ _TO by the operation of the actuator 41. Control so that it goes down to.

The target drive torque T _{OS is set} as the engine 11
Is output to the ECU 15, the ECU 1
5 is the duty ratio of the solenoid valves 51 and 56 for torque control being 0
%, And the engine 11 generates a drive torque corresponding to the amount of depression of the accelerator pedal 31 by the driver.

If it is determined in the step Q5 that the retard ratio is not at the II level, the retard ratio is I in Q8.
It is determined whether or not the level is set. If it is determined in step Q8 that the retard ratio is set to the I level, the target retard amount p _O is set as in the following equation, and the ignition timing P is delayed by the target retard amount p _O. Squaring and Q7
Go to step. p _O = p _B · 2/3

On the other hand, when it is judged in the step Q8 that the retard ratio is not at the I level, it is judged in Q10 whether the target retard amount p _O is 0 or not. If it is determined that the driver has not changed the ignition timing P, the duty ratio of the torque control solenoid valves 51 and 56 is set according to the value of the target drive torque T _OS. The drive torque of the engine 11 is reduced regardless of the depression amount of the accelerator pedal 31 due to.

If it is determined in the step Q10 that the target retardation amount p _O is not 0, the target retardation amount p _O is controlled by the ramp control at the sampling cycle Δt of the main timer in Q11, for example. The value is subtracted one by one until p _O = 0, and after shocks due to fluctuations in the drive torque of the engine 11 are reduced, the process proceeds to step Q7.

If it is determined in step Q1 that the slip control flag F _S has been reset, normal running control that does not reduce the drive torque of the engine 11 is performed, and p _O = 0 in Q12. As the ignition timing P is not retarded, the torque control solenoid valves 51 and 56 are operated at Q13.
By setting the duty ratio to 0%, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 31 by the driver.

By the way, the road surface μ estimating means 113A not only estimates the road surface μ using the power steering pressure or the like, but also estimates the road surface μ from another method, for example, the lateral acceleration applied to the vehicle, the steering angle and the vehicle speed. It may be configured. The road surface μ estimating means in this case will be described with reference to FIGS. 55 to 57. To summarize briefly, the steering angle of the vehicle steering wheel, the lateral acceleration of the vehicle and the vehicle speed are detected, and the stability factor is calculated based on the detected steering angle, lateral acceleration and vehicle speed, and the stability factor is calculated. The value,
This is compared with a predetermined value that is worse than the standard stability factor, and the detected value of lateral acceleration when the calculated value of the stability factor matches the predetermined value is estimated as the friction coefficient of the road surface.

As described above, the stability factor is a value determined by the structure of the suspension system of the vehicle, the characteristics of the tires and the like. Specifically, for example, as shown in FIG. 55, the lateral acceleration G _Y generated in the vehicle during a steady circular turn and the steering angle ratio δ of the steering wheel shaft (steering shaft) at this time.
It is expressed as the slope of the tangent line in the graph showing the relationship with _H / δ _HO . Here, the steering angle ratio δ _H / δ _HO is based on the steering shaft neutral position δ _M with respect to the turning angle δ _HO of the steering shaft in the extremely low speed traveling state where the lateral acceleration G _Y is near 0.
It is the ratio of the turning angle δ _H of the steering shaft during acceleration. Further, the illustrated example is for a front-wheel drive vehicle. And the stability factor is
It can be calculated from (13). A = δ / (G _Y + ω) −1 / V ² (13) δ = δ _H / ρ _H where δ is the steering angle of the steering shaft, δ _H is the turning angle of the steering shaft, and ρ _H
Is the steering gear speed ratio (known), G _Y is the actual lateral acceleration of the vehicle,
ω is the wheelbase of the vehicle (known), and V is the vehicle speed.

Further, in FIG. 55, a curve 201A represents the relationship between the lateral acceleration G _Y and the steering angle ratio δ _H / δ _HO in a steady circular turn on a high μ road such as a dry pavement road. If the coefficient) is μ ₁ , the lateral acceleration G _Y (unit: g) cannot exceed μ ₁ . Then, in a region where the lateral acceleration G _Y is somewhat smaller than μ ₁ and therefore the vehicle speed V is not so high, the stability factor A is substantially constant (for example, A =
0.002), which is a linear relationship region, but when the lateral acceleration G _Y approaches μ ₁ , the stability factor A suddenly increases (deteriorates), and the vehicle exhibits an extremely strong understeering tendency. Like Another curve 202
A, 203A, and 204A have friction coefficients of μ ₂ and μ, respectively.
₃ and μ ₄ (μ ₁ > μ ₂ > μ ₃ > μ ₄ ) on low μ road surfaces, namely road surface wet with rain (μ ₂ ), snow-covered road surface (μ ₃ ), and G _Y on ice (μ ₄ ). Shows the relationship with δ _H / δ _HO .
For any low μ road surface, lateral acceleration G _Y is the same as above.
Cannot exceed the road surface μ, and when the road surface μ is approached, the linear relationship deviates from the linear relationship and the stability factor A rapidly increases.

On the other hand, FIG. 56 is obtained by rewriting FIG. 55 so that the rapid increase of the stability factor A can be clearly understood, and the vertical axis is the stability factor A and the horizontal axis is the lateral acceleration G _Y. In FIG. 56, the curve 201B indicates that the road surface friction coefficient is μ ₁
The curve 202B represents the relationship in the case of μ ₂ ,
The curve 203B shows the relationship in the case of μ ₃ and the curve 204B shows μ
The relationships in case ₄ are shown. Then, a predetermined value A _L (for example, A _{L, which} is larger than the standard stability factor (A = 0.002) in a region having a linear relationship.
= 0.005) the actual lateral acceleration G _Y1 , G _Y2 ,
When G _Y3 and G _Y4 are obtained, they are the friction coefficient μ _{1 of the} road surface,
The values are very close to μ ₂ , μ ₃ , and μ ₄ .

The above is the case of a vehicle having an understeering tendency, but the same can be said for a vehicle having an oversteering tendency.

Therefore, (a) the steering angle δ of the steered wheels of the vehicle, the lateral acceleration G _Y of the vehicle, and the vehicle speed V are detected, and (b) the steering angle δ, the lateral acceleration G _Y, and the vehicle speed V of the vehicle are detected based on the detected steering angle δ. By calculating the stability factor, (c) comparing the calculated value A of the stability factor with a predetermined value A _{L that} is worse than the standard stability factor, (d) the calculated value A of the stability factor is Predetermined value A _L
The detected value G _Y of the lateral acceleration when it matches with can be estimated as the friction coefficient μ of the road surface. In order to prevent an error due to disturbance or the like, a large lateral acceleration G _YTH, such as 0.
It is _recommended to set 5 (g) and not measure when G _Y > G _YTH , or to simply estimate high μ. Also,
In the case of A <A _L , it is advisable not to perform measurement or to simply estimate high μ.

FIG. 57 shows the flow of road surface μ estimation. In step 301, the stability factor A is calculated by the equation (13). Next, at step 302, the calculated value A of the stability factor is compared with a predetermined value A _L, for example 0.005, and the detected lateral acceleration value G _Y is given a predetermined value G _YTH, for example.
Compare with 0.5 (g). The actual lateral acceleration G _Y is detected by linear G
It may be done with a sensor or the like. Then, in step 303,
In the case of A> A _L and G _Y <G _YTH, road surface during traveling is determined to be low mu, at step 304, the detection value of the lateral acceleration when the A = A _L G _Y (g) of , And the friction coefficient μ of the road surface. However, in the case of A <A _L MatawaG _Y> G _YTH, it determines that the road surface is high mu, does not perform estimation of mu. By repeatedly executing the steps 301 to 304 described above according to a predetermined sampling period,
The road surface μ is estimated at all times during driving.

[0230]

According to the vehicle output control apparatus of the present invention,
When reducing the drive torque of the engine in the turning control or the slip control, the cornering drag correction according to the road surface μ is performed. Therefore, the target drive torque on the low μ road is not too large and the target drive torque on the high μ road is not too small, and the output condition corresponding to the road surface condition that changes momentarily and the tire characteristics It can be performed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment in which a vehicle output control device according to the present invention is applied to a front-wheel drive type vehicle in which a hydraulic automatic transmission having four forward speeds and one reverse speed is incorporated.

FIG. 2 is a schematic configuration diagram thereof.

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

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

FIG. 5 is a flowchart illustrating a flow of neutral position learning correction of a steering shaft.

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

FIG. 7 is a flowchart illustrating a flow of neutral position learning correction of the steering shaft.

FIG. 8 is a map showing a relationship between a vehicle speed and a variable threshold value.

FIG. 9 is a graph showing an example of a correction amount when the neutral position of the steering shaft is learned and corrected.

FIG. 10 is a block diagram showing a calculation procedure of a target drive torque for slip control.

FIG. 11 is a block diagram showing a calculation procedure of a target drive torque for slip control.

FIG. 12 is a map showing the relationship between vehicle speed and correction coefficient.

FIG. 13 is a map showing the relationship between vehicle speed and running resistance.

FIG. 14 is a map showing a relationship between a steering shaft turning amount and a correction torque.

FIG. 15 is a map that regulates the lower limit of the target drive torque immediately after the start of slip control.

FIG. 16 is a graph showing a relationship between a friction coefficient between a tire and a road surface and a slip ratio of this tire.

FIG. 17 is a map showing a relationship between a target lateral acceleration and a slip correction amount associated with acceleration.

FIG. 18 is a map showing a relationship between lateral acceleration and a slip correction amount associated with turning.

FIG. 19 is a circuit diagram for detecting an abnormality in the steering angle sensor 84.

FIG. 20 is a flowchart showing a flow of abnormality detection processing of a steering angle sensor.

FIG. 21 is a map showing the relationship between vehicle speed and correction coefficient.

FIG. 22 is a flowchart showing the flow of a procedure for selecting lateral acceleration.

FIG. 23 is a map showing a relationship between a slip amount and a proportional coefficient.

FIG. 24 is a map showing a relationship between a vehicle speed and a lower limit value of integral correction torque.

FIG. 25 is a graph showing an increase / decrease region of integral correction torque.

FIG. 26 is a map showing a relationship between each shift speed of the hydraulic automatic transmission and a correction coefficient corresponding to each correction torque.

FIG. 27 is a map showing the relationship among engine speed, required drive torque, and accelerator opening.

FIG. 28 is a flowchart showing the flow of slip control.

FIG. 29 is a block diagram showing a procedure for calculating a target drive torque for turning control.

FIG. 30 is a block diagram showing a procedure for calculating a target drive torque for turning control.

FIG. 31 is a map showing the relationship between vehicle speed and correction coefficient.

FIG. 32 is a graph showing the relationship between lateral acceleration and steering angle ratio for explaining the stability factor.

FIG. 33 is a map showing the relationship between target lateral acceleration, target longitudinal acceleration, and vehicle speed.

FIG. 34 is a map showing a relationship between lateral acceleration and road load torque.

FIG. 35 is a graph showing an example of a procedure for learning correction of the fully closed position of the accelerator opening sensor.

FIG. 36 is a flowchart showing another example of the flow of learning correction of the fully closed position of the accelerator opening sensor.

FIG. 37 is a flowchart showing another example of the flow of learning correction of the fully closed position of the accelerator opening sensor.

FIG. 38 is a flowchart showing the flow of turning control.

FIG. 39 is a flowchart showing a flow of turning control.

FIG. 40 is a flowchart showing the flow of a final target torque selection operation.

FIG. 41 is a flowchart showing the flow of a retard angle ratio selecting operation.

FIG. 42 is a flowchart showing the flow of a retard angle selection operation.

FIG. 43 is a flowchart showing a procedure of engine output control.

FIG. 44 is a flow chart showing a procedure of engine output control.

FIG. 45 is a flowchart showing the setting of the stability factor using the estimated value of the road surface μ.

FIG. 46 is a flowchart showing a cornering drag correction and an addition ratio calculation using an estimated value of a road surface μ.

FIG. 47 is a diagram showing a power steering device.

FIG. 48 is a diagram showing a steering situation of the right front wheel.

FIG. 49 is a diagram showing the relationship between cornering force and sideslip angle.

FIG. 50 is a diagram showing a calculation procedure.

FIG. 51 is a diagram showing changes in steering shaft turning angle and power steering pressure.

FIG. 52 is a flowchart of an estimation operation.

FIG. 53 is a flowchart of an estimation operation.

FIG. 54 is a diagram showing a relationship between a multiplication coefficient and a vehicle speed.

FIG. 55 is a diagram showing a relationship between a steering angle ratio and a lateral G on various road surfaces.

FIG. 56 is a diagram showing the relationship between the stability factor and the lateral G on various road surfaces.

FIG. 57 is a flowchart of an estimation operation.

[Explanation of symbols]

11 Engine 13 Hydraulic Automatic Transmission 15 ECU 16 Hydraulic Control Device 20 Throttle Valve 23 Accelerator Lever 24 Throttle Lever 31 Accelerator Pedal 32 Cable 34 Claw 35 Stopper 41 Actuator 43 Control Rod 47 Connection Piping, 48 Vacuum Tank 49 Check Valve 50 , 55 Piping 51, 56 Torque control solenoid valve 60 Solenoid valve 61 Spark plug 62 Crank angle sensor 64, 65 Front wheel 66 Front wheel rotation sensor 67 Throttle opening sensor 68 Idle switch 70 Air flow sensor 71 Water temperature sensor 74 Exhaust temperature sensor 75 Ignition key Switch 76 TCL 77 Accelerator opening sensor 78, 79 Rear wheel 80, 81 Rear wheel rotation sensor 82 Vehicle 83 Steering shaft 84 Steering angle sensor 85 Steering handle 86 Steering shaft reference position sensor 87 Communication Cable 91 Power Actuator 92 Power Steering Device 93 Tie Rod 94 Steering Valve 95 Hydraulic Pump 96 Reservoir Tank 98, 99 Pressure Sensor 104, 105, 117, 135 Multiplier 106, 131 Differential Calculator 107, 110 Clip 108, 123 Filter Section 109 torque conversion section 111 running resistance calculation section 112, 114, 119 addition section 113 cornering drag correction amount calculation section 113A road surface μ estimation means 115 variable clip section 116, 121, 124 subtraction section 118 acceleration correction section 120 turning correction section 122 lateral Acceleration calculation unit 141 Target lateral acceleration calculation unit 141A Stability factor (A) setting means 144 Longitudinal acceleration calculation unit 145 Reference drive torque calculation unit 145A Cornering drag correction amount calculation unit 46,147 multiplication section 146A addition ratio α calculating unit A stability factor b tread D _F cornering force F _P ignition timing control flag F _S slip control flag G _F actual front wheel acceleration G _KC, G _KF wheel acceleration correction amount G _s Slip amount change rate G _XF Corrected longitudinal acceleration G _XO Target longitudinal acceleration G _YO Target lateral acceleration g Gravity acceleration N _E Engine speed P Ignition timing p _B Basic retard amount p _o Target retard amount P _S Power steering pressure r Wheel effective Radius S _O Target slip ratio s Slip amount T _B Reference drive torque T _C Cornering drag correction torque T _D Differential correction torque T _d Required drive torque T _I Integral correction torque T _O Final target drive torque T _OC Target drive torque for turning control T _OS for slip control target driving torque T _P proportional correction torque T _PID final correction torque T _R running resistance Δt sampling period V vehicle speed _F actual front wheel speed V _FO, V _FS target front wheel speed V _K, V _KC slip correction amount V _RL left rear wheel speed V _RR right rear wheel speed V _S for slip control speed W _b vehicle weight [delta] front wheel steering angle [delta] _H Steering axis turning angle δ _F Side slip angle ρ _d Differential gear reduction ratio ρ _KI integral correction coefficient ρ _KP proportional correction coefficient ρ _m Hydraulic automatic transmission gear ratio ρ _T Torque converter ratio μ Road friction coefficient

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-10437 (JP, A) JP 62-253228 (JP, A) JP 62-3137 (JP, A)

Claims (2)

(57) [Claims] 1. A torque control means for reducing a drive torque of an engine independently of a driver's operation, a steering angle sensor for detecting a turning angle of a steering shaft, a vehicle speed sensor for detecting a vehicle speed, and a road surface sensor. A means for estimating a friction coefficient, a means for calculating a cornering drag correction torque according to the estimated road surface friction coefficient, a lateral acceleration of the vehicle based on detection signals from the steering angle sensor and the vehicle speed sensor, and A torque calculation unit that calculates a basic drive torque according to the magnitude of the lateral acceleration and calculates a target drive torque from the sum of the basic drive torque and the cornering drag correction torque, and the output torque of the engine is the target drive torque. And an electronic control unit that controls the torque control means so that the output control device for a vehicle is provided. 2. A torque reducing means for reducing a drive torque of an engine independently of a driver's operation, a reference drive torque setting means for setting a reference drive torque of the engine based on a traveling speed of a vehicle, and a road surface. Means for estimating the friction coefficient of the vehicle, means for calculating the cornering drag correction torque according to the estimated road surface friction coefficient, target drive wheel speed setting means for setting the target peripheral speed of the drive wheels, and actual drive wheel speed detection Means, a correction torque calculating means for calculating a correction torque from the deviation between the actual drive wheel speed and the target drive wheel speed, and the correction torque is subtracted from the sum of the set reference torque and the cornering drag correction torque. The target drive torque setting means for setting a target drive torque of the engine and the operation of the torque reducing means so that the drive torque of the engine becomes the set target drive torque. An output control device for a vehicle, comprising: a torque control unit for controlling.