JP2518450B2 - Vehicle output control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention is intended to reduce the drive torque of an engine rapidly in accordance with the slip amount of a drive wheel at the time of acceleration of a vehicle and to drive the vehicle safely. The present invention relates to an output control device for a vehicle.

<Prior art> When a vehicle drastically changes the condition of the road surface or when the vehicle runs on a slippery low friction coefficient road surface, such as a snow road or an icy road, the drive wheels spin idle. There is a risk that the driver of the vehicle may not be able to drive as intended.

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.

Therefore, 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. A possible output control device is considered, and the driver uses the output control device as necessary,
It has been announced that normal driving, in which the output of the engine is controlled according to the amount of depression of the accelerator pedal, can be selected.

Among those related to the output control of the vehicle based on such a viewpoint, conventionally known ones, for example, set the target drive torque of the engine in accordance with the traveling state of the vehicle, while the rotational speed of the drive wheels and the driven wheels are set. The rotational speed is detected, the difference in rotational speed between the drive wheel and the driven wheel is regarded as the slip amount of the drive wheel, and the target drive torque is corrected according to the slip amount.

Then, the correction torque with respect to the target drive torque is calculated in proportion.

<Problems to be Solved by the Invention> In this conventional output control device, since the slip amount is used as it is and multiplied by the proportional coefficient, there is a disadvantage that over-control is performed and output hunting occurs.

The present invention aims to solve the above-mentioned problems of the prior art.

<Means for Solving the Problem> To prevent overcontrol, the lower limit of the slip amount may be clipped, that is, the correction for increasing the target drive torque may be suppressed to some extent.

In addition, it is necessary to prevent excessive slippage of the drive wheels and effectively use the drive torque of the engine, which can be considered as follows.

When the vehicle is traveling other than at extremely low speeds, the drive wheels are more or less slipping with respect to the road surface. However, as is well known empirically, it is difficult to steer the vehicle when a driving torque larger than the frictional force between the road surface and the driving wheels is applied, the slip amount of the driving wheels suddenly increases. is there.

For this reason, in order to effectively use the drive torque generated by the engine and prevent slippage of the drive wheels that makes it difficult to steer the vehicle, the drive torque of the engine must be controlled by the friction between the road surface and the drive wheels. It is desirable to control the drive torque of this engine so as not to exceed the maximum force much.

In other words, in order to make effective use of the drive torque generated in the engine, as shown in FIG. 13 showing the relationship between the slip ratio S of the tire and the coefficient of friction between the tire and the road surface, as shown in FIG. The slip of the driving wheels is set so that the slip ratio S of the titer becomes a target slip ratio S _O corresponding to the maximum value of the friction coefficient between the tire and the road surface or a value near the target slip ratio S _O that is smaller than the target slip ratio S _O. It is desirable to adjust the amount to avoid energy loss and at the same time not to impair the vehicle's controllability and acceleration.

Here, when V is the speed of the vehicle (hereinafter referred to as vehicle speed) and V _D is the peripheral speed of the driving wheels, the slip ratio S of the tire is The driving torque of the engine 11 may be set such that the slip ratio S becomes a smaller value at or near the target slip ratio S _O corresponding to the maximum value of the friction coefficient between the tire and the road surface. .

The output control device for a vehicle according to the present invention has been made in view of such knowledge, and a torque reducing means capable of reducing the drive torque of the engine independently of the operation by the driver, and a method for driving the vehicle by the engine. Reference drive torque setting means for setting the reference drive torque as the reference value of the drive torque based on the vehicle body acceleration of the vehicle, and the actual drive wheel speed for setting the reference drive torque of the engine based on the traveling speed of the vehicle. When the deviation between the actual driving wheel speed and the target driving wheel speed is smaller than the negative lower limit value, the lower limit value is output as the deviation, while the deviation is greater than or equal to the lower limit value. In this case, clipping means for outputting the deviation as it is, and proportional correction torque calculating means for calculating a correction torque proportional to the deviation output from the clipping means,
Target drive torque setting means for setting the target drive torque of the engine by subtracting the correction torque from the set reference drive torque, and so that the drive torque of the engine approaches the set target drive torque. And a torque control unit for controlling the operation of the torque reducing means.

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

<Operation> The reference drive torque setting means sets the reference drive torque based on the vehicle body acceleration. The clipping means outputs the lower limit value as the deviation when the deviation between the actual driving wheel speed and the target driving wheel speed is smaller than the negative lower limit value, and outputs the deviation as it is when the deviation is equal to or more than the lower limit value. The proportional correction torque calculation means calculates a correction torque proportional to the deviation output from the clipping means. Then, the target drive torque setting means subtracts the correction torque to set the target drive torque from the reference drive torque, and outputs this to the torque control unit.

When the target drive torque of the engine is output from the target drive torque setting means to the torque control unit, the torque control unit controls the operation of the torque reducing means so that the drive torque of the engine becomes the target drive torque, and the operation is performed. The drive torque of the engine is reduced as necessary regardless of the operation by the person.

In this case, when the deviation is smaller than the negative lower limit value, the lower limit value is set as the deviation, and when the deviation is equal to or larger than the lower limit value, the deviation is used as it is, so that the slip of the driving wheels converges and the actual driving is performed. When the deviation between the wheel speed and the target drive wheel speed becomes a negative value and the target drive torque increases due to the correction torque, the deviation value is limited to the negative lower limit value by clipping (clipping) by the lower limit value. Since it does not become smaller, stable control can be realized without excessively increasing the target drive torque, while the above-mentioned deviation becomes a positive value when slip occurs on the drive wheels. Since there is no limit (clip) due to the lower limit value, the correction torque proportional to the deviation is subtracted from the reference drive torque as it is, so that the target drive torque can be quickly reduced. It is possible to converge the slip.

<Embodiment> FIG. 1 showing the concept of one embodiment in which the 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, the input shaft 14 of the hydraulic automatic transmission 13 is connected to the output shaft 12 of the engine 11. This hydraulic automatic transmission 13 is an electronic control unit (hereinafter referred to as an ECU) 15 that controls the operating state of the engine 11 according to the selection position of a select lever (not shown) by the driver and the operating state of the vehicle. On the basis of a command from, a predetermined gear stage is automatically selected via the hydraulic control device 16.
The specific structure and operation of the hydraulic automatic transmission 13 are described in, for example, JP-A-58-54270 and JP-A-61-31749.
As is already well known in Japanese Patent Publication No. JP-A-2003-138, and the like, not shown for performing engagement operation and release operation of a plurality of friction engagement elements forming a part of the hydraulic automatic transmission 13 in the hydraulic control device 16. A pair of shift control solenoid valves is incorporated, and by controlling the ON / OFF operation of the energization to these shift control solenoid valves by the ECU 15, the shift operation to any gear position among the four forward gears and the one reverse gear can be performed. Achieve smoothly.

In the middle of the intake pipe 18 connected to the combustion chamber 17 of the engine 11,
A throttle body 21 incorporating a throttle valve 20 that adjusts the opening degree of an intake passage 19 formed by the intake pipe 18 and adjusts the amount of intake air supplied into the combustion chamber 17 is interposed. As shown in FIG. 1 and FIG. 3 showing the enlarged cross-sectional structure of this cylindrical throttle body 21,
On the throttle body 21, both ends of a throttle shaft 22 to which the throttle valve 20 is integrally fixed are rotatably 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.

A bush 26 and a spacer 27 are interposed between the throttle shaft 22 and the cylinder portion 25 of the accelerator lever 23, whereby the accelerator lever 23 is rotatable with respect to the throttle shaft 22. Further, the washer 28 and the nut 29 attached to one end of the throttle shaft 22 prevent the accelerator lever 23 from coming off the throttle shaft 22. Also, the cable receiver 30 integrated with the accelerator lever 23
An accelerator pedal 31 that is operated by the driver is connected via a cable 32, and the accelerator lever 23 rotates with respect to the throttle shaft 22 in accordance with the amount of depression of the accelerator pedal 31. .

On the other hand, the throttle lever 24 is fixed integrally with the throttle shaft 22, so that by operating the throttle lever 24, the throttle valve 20
Rotate with. Further, a collar 33 is coaxially and integrally fitted to the tubular portion 25 of the accelerator lever 23, and the tip end portion of the throttle lever 24 is engaged with a claw portion 34 formed on a part of the collar 33. A stopper 35 that can be used is formed.
The claw portion 34 and the stopper 35 are locked to each other when the throttle lever 24 is rotated in the direction of opening the throttle valve 20 or the accelerator lever 23 is rotated in the direction of closing the throttle valve 20. It is set in a proper positional relationship.

Between the throttle body 21 and the throttle lever 24, a torsion coil spring 36 for pressing a stopper 35 of the throttle lever 24 against a claw portion 34 of a collar 33 integrated with the accelerator lever 23 to urge the throttle valve 20 in the opening direction. Is a pair of cylindrical spring receivers 37, 3 fitted to the throttle shaft 22.
It is mounted coaxially with the throttle shaft 22 via 8. The collar 33 is also provided between the stopper pin 39 protruding from the throttle body 21 and the accelerator lever 23.
The torsion coil spring 40 for pressing the claw portion 34 of the lever 34 against the stopper 35 of the throttle lever 24 to urge the throttle valve 20 in the closing direction to give a detent feeling to the accelerator pedal 31 is provided through the collar 33. It is mounted on the cylinder portion 25 of the lever 23 so as to be coaxial with the throttle shaft 22.

The tip of the throttle lever 24 is connected to the tip of a control rod 43 whose base end is fixed to the diaphragm 42 of the actuator 41. 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. And these two springs
The spring force of the torsion coil spring 40 is set to be larger than the sum of the spring forces of 36 and 45, so that the throttle valve 20 does not open unless the accelerator pedal 31 is depressed.

A connection pipe 47 is connected to a surge tank 46 which is connected to the downstream side of the throttle body 21 and forms a part of the intake passage 19.
The vacuum tank 48 communicates with each other via a check valve 49, which allows only the movement of air from the vacuum tank 48 to the surge tank 46, between the vacuum tank 48 and the connection pipe 47. There is. As a result, the pressure in the vacuum tank 48 is set to a negative pressure substantially equal to the minimum pressure in the surge tank 46.

Inside the vacuum tank 48 and the actuator 41
The pressure chamber 44 is in communication with the pressure chamber 44 via a pipe 50. In the middle of the pipe 50, a non-energized first torque control solenoid valve 51 is provided. In other words, the torque control solenoid valve 51 has a plunger 52 so as to close the pipe 50.
A spring 54 for urging the valve seat 53 against the valve seat 53 is incorporated.

A pipe 55 connecting to the first torque control solenoid valve 51 and the actuator 41 is connected to a pipe 55 communicating with the intake passage 19 on the upstream side of the throttle valve 20. A second torque control solenoid valve 56 that is open when not energized is provided in the middle of the pipe 55. That is, the torque control solenoid valve 56 incorporates the spring 58 that biases the plunger 57 so as to open the pipe 55.

The two torque control solenoid valves 51, 56 include the ECU 15
Are connected to each other, and duty on / off of energization to the torque control solenoid valves 51 and 56 is controlled based on a command from the ECU 15. Means.

For example, when the duty ratio of the torque control solenoid valves 51, 56 is 0%, the pressure chamber 44 of the actuator 41 becomes an atmospheric pressure substantially equal to the pressure in the intake passage 19 upstream of the throttle valve 20, and the throttle valve 20 Is the accelerator pedal 31
One-to-one correspondence with the depression amount of. On the contrary, when the duty ratio of the torque control solenoid valves 51, 56 is 100%, the pressure chamber 44 of the actuator 41 becomes a negative pressure almost equal to the pressure in the vacuum tank 48, and the control rod 43 is left in FIG. As a result of being lifted diagonally upward, the throttle valve 20 becomes an accelerator pedal.
It is closed regardless of the depression amount of 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, 56, the opening degree of the throttle valve 20 is changed regardless of the depression amount of the accelerator pedal 31, and the drive torque of the engine 11 is arbitrarily adjusted. can do.

Further, in the present 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 valve is used as an accelerator. It is also possible to connect only the pedal 31 and the other throttle valve only to the actuator 41, and control these two throttle valves independently.

On the other hand, the combustion chamber of the engine 11 is provided on the downstream end side of the intake pipe 18.
Fuel injection nozzles 59 of a fuel injection device for injecting fuel (not shown) into 17 are provided respectively corresponding to each cylinder of the engine 11 (in this embodiment, a four-cylinder internal combustion engine is assumed). Fuel is supplied to the fuel injection nozzle 59 via a controlled solenoid valve 60. That is, by controlling the valve opening time of the solenoid valve 60, the amount of fuel supplied to the combustion chamber 17 is adjusted, and the combustion chamber 17 has a predetermined air-fuel ratio.
It is adapted to be ignited by a spark plug 61 inside.

The ECU 15 includes a crank angle sensor 62 attached to the engine 11 for detecting the engine speed, and a pair of left and right drive wheels that detect the speed of the output shaft 63 of the hydraulic automatic transmission 13. A front wheel rotation sensor 66 for calculating the average peripheral speed of the front wheels 64, 65, a throttle opening sensor 67 attached to the throttle body 21 for detecting the opening of the throttle lever 24, and a fully closed state of the throttle valve 20 are detected. In addition to the idle switch 68 for detection, an air cleaner 69 at the tip of the intake pipe 18
An air flow sensor 70, such as a Karman vortex flowmeter, which is installed inside and detects the amount of air flowing into the combustion chamber 17 of the engine 11,
A water temperature sensor 71 attached to the engine 11 to detect a cooling water temperature of the engine 11, and an exhaust temperature sensor attached to the exhaust pipe 72 to detect the temperature of exhaust gas flowing through the exhaust passage 73
74 and the ignition key switch 75 are connected.

Then, the crank angle sensor 62, the front wheel rotation sensor 66, the throttle opening sensor 67, and the idle switch.
Output signals from the 68, the air flow sensor 70, the water temperature sensor 71, the exhaust temperature sensor 74, and the ignition key switch 75 are respectively sent to the ECU 15.

Further, a torque calculation unit (hereinafter referred to as TCL) 76 for calculating a target drive torque of the engine 11 is attached to the throttle body 21 together with the throttle opening sensor 67 and the idle switch 68, and is connected to the accelerator lever 23. An accelerator opening sensor 77 that detects the opening, rear wheel rotation sensors 80 and 81 that detect the rotational speeds of the pair of left and right rear wheels 78 and 79, which are driven wheels, respectively, and a turning state based on the straight traveling state of the vehicle 82. The normal angle of the steering angle sensor 84 for detecting the turning angle of the steering shaft 83 and the steering wheel 85 integrated with the steering shaft 83 for every 360 degrees (including the phase in which the vehicle 82 is in a substantially straight traveling state) Is connected to the steering axis reference position sensor 86, which outputs output signals from these sensors 77, 80, 81, 84, 86, respectively.

The ECU 15 and the TCL 76 are connected via a communication cable 87, and from the ECU 15, the engine speed, the rotation speed of the output shaft 63 of the hydraulic automatic transmission 13, the detection signal from the idle switch 68, etc. Operating status information is sent to TCL76. On the contrary, the TCL76 sends information about the target drive torque calculated by the TCL76 and the retardation rate of the ignition timing to the ECU 15.

In the present embodiment, when the slip amount in the front-rear direction of the front wheels 64, 65 that are the drive wheels becomes larger than a preset amount, the drive torque of the engine 11 is reduced to ensure maneuverability and energy loss. The target drive torque of the engine 11 and the lateral acceleration (hereinafter, referred to as lateral acceleration) generated in the turning vehicle when the control for preventing (hereinafter, referred to as slip control) is performed are performed in advance. When the value is equal to or greater than the set value, control for reducing the drive torque of the engine 11 so that the vehicle does not deviate from the turning circuit (hereinafter,
The target drive torque of the engine 11 when performing the turning control) is calculated by the TCL76, and the optimum final target drive torque is selected from these two target drive torques, and the drive torque of the engine 11 is selected. To be reduced as necessary. Further, even if the throttle valve 20 is fully closed via the actuator 41, 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, and the drive torque of the engine 11 is rapidly reduced. I am able to do it.

As shown in FIG. 4 which shows the rough flow of the control according to the present embodiment, in the present embodiment, the target drive torque T _OS of the engine 11 when the slip control is performed and the target drive torque T _OS when the turning control is performed are performed. The target drive torque T _OS of the engine 11 is always calculated in parallel by the TCL76, and these two target drive torques T _OS , T _OS
The optimum final target drive torque T _O is selected from the _OS so that the drive torque of the engine 11 can be reduced as necessary.

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

Then, based on the detection signals from various sensors in M2
The TCL 76 calculates the vehicle speed V and the like, and subsequently learns and corrects the neutral position δ _M of the steering shaft 83 at M3. The steering axis 8 of this vehicle 82
Since the neutral position δ _{M of} 3 is not stored in a memory (not shown) in the ECU 15 or the TCL 76, the initial value δ _{m (o)} is read every time the ignition key switch 75 is turned on, and the vehicle 82 will be described later. Learning correction is performed only when the straight running condition is satisfied, and this initial value Δm _(o) is learned and corrected until the ignition key switch 75 is turned off.

Next, TCL76 is a target drive torque T in the case of 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 detection signals from the rear wheel rotation sensors 80 and 81 at M4. Calculate the _OS and use M5 to measure the rear wheel rotation sensor 8
The target drive torque T _OC of the engine 11 when the turning control for restricting the drive torque of the engine 11 is performed is calculated based on the detection signals from the 0, 81 and the steering angle sensor 84.

Then, at M6, the TCL76 determines these target driving torques T _OS , T
_The optimum final target drive torque T _O is selected from _OC by a method described later mainly in consideration of safety. Furthermore, when the vehicle is suddenly started or when the road surface suddenly changes from a normal dry road to a frozen road, the output of the engine 11 may not be reduced in time even by fully closing the throttle valve 20 via the actuator 41. Therefore, the change rate G of the slip amount s of the front wheels 64 and 65 at M7
Based on _s , select the retard ratio for correcting the basic retard amount p _B , and set the final target drive torque T _O and the basic retard amount.
The data regarding the retardation ratio of p _B is output to the ECU 15 by M8.

If the driver operates a manual switch (not shown) and desires slip control or turning control, the ECU 1
Reference numeral 5 is data for controlling the duty ratio of the pair of torque control solenoid valves 51, 56 so that the drive torque of the engine 11 becomes the final target drive torque T _O, and further for the retard ratio of the basic retard amount p _B. Based on the above, the target retardation amount p _O is calculated in the ECU 15, and the ignition timing P is delayed by the target retardation amount p _o as necessary, so that the vehicle 82 travels reasonably and safely.

If the driver does not desire slip control or turning control by operating a manual switch (not shown), ECU1
5 indicates that the duty ratio of the pair of torque control solenoid valves 51, 56 is 0.
As a result of setting to the% side, the vehicle 82 is set to the driver's accelerator pedal.
The normal operating state corresponding to the depression amount of 31 is entered.

In this way, the drive torque of the engine 11 is controlled by M9 until the countdown every 15 milliseconds which is the sampling period of the main timer is completed, and thereafter the steps from M2 to M10 are turned off by the ignition key switch 75. Repeat until the condition is reached.

By the way, the turning control is performed in the step of M5, and the engine 11
When calculating the target drive torque T _oc of the vehicle, 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 also based on the detection signal from the steering angle sensor 84. The steering angle δ of the front wheels 64, 65 is calculated from the following equation (2), and the target lateral acceleration G _YO of the vehicle 82 at this time is calculated by the following equation (3).
We are asking for each.

Where V _RL and V _RR are the peripheral speeds of the 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 turning angle of the steering shaft 83. , L is the wheel base of the vehicle 82, and A is the stability factor of the vehicle 82 described later.

As is clear from the equation (3), the neutral position δ _M of the steering shaft 83 is changed by the toe-in adjustment of the front wheels 64, 65 during the maintenance of the vehicle 82 and the secular change such as wear of the steering gear (not shown). When will change, deviation between the actual steering angle [delta] of the front wheels 64, 65 pivot the position [delta] _m and the steering wheel of the steering shaft 83 is generated. As a result, the target lateral acceleration G _YO of the vehicle 82 may not be able to be accurately calculated, and it becomes difficult to perform good turning control. Moreover, in the present embodiment, during slip control in the step of M4, the cornering drag correction means described later corrects the reference drive torque of the engine 11 based on the turning angle δ _H of the steering shaft 83, etc. ,
Slip control may not be performed well. 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 FIG. 5 showing 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 in the 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. Therefore, the learning correction of the neutral position Δ _M of the steering shaft 83 is not performed because there is a fear.

On the other hand, if it is determined that the vehicle 82 in step H1 is not in the turning control, since not occur inconvenience even if the neutral position [delta] _M of the learning correction of the steering shaft 83, TCL76 the rear wheel rotation sensor 80 The vehicle speed V for learning the neutral position δ _M at H2 and for turning control to be described later is calculated based on the detection signals from the signals 81 and 81 by the formula (1). Next, TCL76 is rear wheel speed V at H3
_RL , V _RR difference (hereinafter referred to as rear wheel speed difference) | V _RL
After calculating −V _RR |, the TCL 76 determines whether or not the learning correction of the neutral position δ _M has been performed while the reference position δ _N of the steering shaft 83 is detected by the steering shaft reference position sensor 86 at H4, that is, It is determined whether or not the steering angle neutral position learned flag F _HN with the reference position Δ _N of the steering shaft 83 detected 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, since the neutral position δ _M is learned for the first time, the steering shaft turning position δ calculated this time at H5. _It is determined whether or not _{m (n)} is equal to the steering shaft turning position Δm _(n-1) calculated last time. On this occasion,
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 shake of the driver's hand.

When it is determined in step H5 that the steering axis turning position δ _{m (n)} calculated this time is equal to the steering axis turning position δ _{m (n-1)} calculated last time, the vehicle speed V is determined in H6. It is determined whether it is larger than a preset threshold value V _A. This operation is
If the speed does not reach a certain level, the rear wheel speed difference due to steering
It is necessary because V _RL −V _RR | etc. cannot be detected.
The threshold value V _A is appropriately set, for example, at 10 km / h by an experiment based on the traveling characteristics of the vehicle 82 and the like.

When it is determined that the vehicle speed V is greater than or equal to the threshold V _A at H6 step, TCL76 rear wheel speed difference at H7 | V _RL -V
_It is determined whether or not _RR | is smaller than a preset threshold value V _X such as 0.3 km / hour, that is, whether or not the vehicle 82 is in a straight traveling state. Here, the threshold value V _X is not set to 0 km / h when the tire pressures of the left and right rear wheels 78, 79 are not equal, the pair of left and right rear wheels 78, 79 is left straight even though the vehicle 82 is in a straight traveling state. This is to avoid determining that the vehicle 82 is not in a straight traveling state due to different peripheral velocities V _RL and V _RR .

In the case the tire pressure of the right and left rear wheels 78 and 79 are not equal, the rear wheel speed difference | V _RL -V _RR | so has a greater tendency in proportion to the vehicle speed V, and the threshold value V _X e.g. A map is created as shown in FIG. 6, and the vehicle speed V is calculated from this map.
The threshold value V _X may be read based on

Rear wheel speed difference at this H7 of step | V _RL -V _RR | threshold V _X
If it is determined to be less than or equal to determines whether the steering shaft reference position sensor 86 has detected the reference position [delta] _N of the steering shaft 83 at H8. Then, the steering shaft reference position sensor 86 is determined in step H8 is detecting the reference position [delta] _N of the steering shaft 83, that is, when the vehicle 82 is determined to be straight state,
At H9, the count of the first learning timer (not shown) built in the TCL76 is started.

Next, the TCL76 determines at H10 whether or not 0.5 seconds has elapsed from the start of counting of the first learning timer, that is, whether or not the straight traveling state of the vehicle 82 has continued for 0.5 seconds. If 0.5 seconds has not elapsed since the timer started counting, it is determined in H11 whether the vehicle speed V is higher than the threshold value V _A. If it is determined in step H11 that the vehicle speed V is greater than the threshold value _VA , then in H12 the rear wheel speed difference | V _RL −
It is determined whether V _RR | is below a threshold V _{B such} as 0.1 km / h. Rear wheel speed difference at this H12 step | 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, shown incorporated in the TCL76 at H13 The second learning timer starts counting.

Then, at H14, it is determined whether or not 5 seconds have elapsed from the start of counting of the second learning timer, that is, whether or not the straight traveling state of the vehicle 82 has continued for 5 seconds. If 5 seconds have not passed since
Returning to step H, the operations from step H2 to step H14 are repeated.

It is determined that the steering shaft reference position sensor 86 detects the reference position δ _N of the steering shaft 83 in the step H8 during this repetitive operation, and the count of the first learning timer is counted in the step H9. If it is determined that 0.5 seconds have elapsed from the start of counting of the first learning timer at H10, that is, if the straight traveling state of the vehicle 82 has continued for 0.5 seconds at H10, the steering shaft 83 at H15 is started.
Steering angle neutral position sets the learned flag F _HN, steering angle neutral position learned flag in further state that the reference position [delta] _N of the steering shaft 83 is not detected at H16 in a state where the reference position [delta] _N has been detected Determine if F _H is set. Also, the above H1
Even when it is determined in step 4 that 5 seconds have elapsed since the second learning timer started counting, the process proceeds 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 is not yet detected is not set, the reference position δ _N of the steering shaft 83 is set at this step H16. It is determined that the learning of the neutral position δ _M is the first time when the steering angle neutral position learned flag F _{H in the} undetected state is not set, that is, the reference position δ _N of the steering shaft 83 is detected. Current steering shaft turning position δ _{m (n)} at H17
Is regarded as the neutral position δ _{M (n)} of the new steering axis 83, and this is regarded as TC
It is read into the memory in L76 and the reference position of steering shaft 83 δ _N
The steering angle neutral position learned flag F _H is set in the state where is not detected.

In this way, after setting a new neutral position δ _{M (n)} of the steering shaft 83, the turning angle δ _H of the steering shaft 83 is calculated with reference to the neutral position δ _M of the steering shaft 83, while H18 is calculated. Then, the count of the learning timer is cleared, and the steering angle neutral position learning is performed again.

The steering axis turning position δ _{m (n)} calculated this time in step H5 is the steering axis turning position δ _{m (n-1)} calculated last time.
Equally if it is determined and that there is no, the vehicle speed V is not above the threshold value V _A at H11 step, i.e. wheel speed difference after being calculated in H12 step | is unreliable | V _RL -V _RR If judged, or in step H12, rear wheel speed difference ｜ V _RL −V _RR
When it is determined that | is larger than the threshold value V _B , the vehicle 82 is not in a straight traveling state in either case, and thus the process proceeds to the step H18.

Further, when it is judged that the rear wheel speed difference | V _RL −V _RR | is larger than the threshold value V _{X in} the step H7, or the steering shaft reference position sensor 86 detects the reference position δ of the steering shaft 83 in the step H8. If it is determined that _N is not detected, the count of the first learning timer is cleared in H19 and the process proceeds to the step of H11, but the vehicle speed V is equal to or less than the threshold V _{A in} the step of H6. If it is determined that the vehicle 82 is in the straight traveling state, the process proceeds to step H11.

On the other hand, in the step H4, the reference position δ _{N of the} steering shaft 83
When the steering angle neutral position learned flag F _HN is set in the state where is detected, that is, when it is determined that the learning of the neutral position δ _M is the second time or later, the steering axis reference position sensor is detected at H20. It is determined whether or not 86 detects the reference position Δ _N of the steering shaft 83. When it is determined in step H20 that the steering shaft reference position sensor 86 detects the reference position δ _N of the steering shaft 83, whether the vehicle speed V is greater than the preset threshold V _A in H21. Determine whether or not.

If the vehicle speed V is equal to or greater than the threshold value V _A is at this H21 step, TCL76 rear wheel speed difference at H22 | V _RL -V _RR
It is determined whether or not | is smaller than the threshold value V _X , that is, whether or not the vehicle 82 is in a straight traveling state. Then, if it is determined in this step H22 that the rear wheel speed difference | V _RL −V _RR | is smaller than the threshold value V _X , the steering shaft turning position δ _{m (n)} calculated this time in H23 is Calculated steering axis turning position δ _{m (n-1)}
It is determined whether or not 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) , the process proceeds to step H24.
Then, the counting of the first learning timer is started.

Next, the TCL76 determines at H25 whether or not 0.5 seconds has elapsed from the start of counting of this first learning timer, that is, whether the straight traveling state of the vehicle 82 has continued for 0.5 seconds, and the first learning timer If 0.5 seconds has not elapsed from the start of counting, the process returns to the step H2, and the steps H2-H4 and H20-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.

The steering shaft reference position sensor 8
6 determines that the reference position δ _N of the steering shaft 83 is not detected, or the vehicle speed V is not equal to or higher than the threshold value _{VA in} the step H21, that is, the rear wheel speed difference calculated in the step H22 | V _RL −
If it is judged that V _RR ｜ is not reliable, or if the rear wheel speed difference ｜ V _RL −V _RR ｜ is larger than the threshold value V _{X in} the step of H22, or this time is calculated in the step of H23. The calculated steering axis turning position δ _{m (n)} is the previously calculated steering axis turning position δ
If it is determined that _m is not equal to _(n-1) , any of the above
Go to step H18.

Rudder angle neutral position learned flag F _{H in} step H16
Is set, that is, when it is determined that the learning of the neutral position δ _M is the second time or later, the current steering shaft turning position δ _{m (n)} at H26 is TCL76, and the previous steering shaft 83 neutral position δ
It is determined whether it is equal to _{m (n-1)} , that is, δm _(n) = δM _(n-1) . If it is determined that the current steering shaft turning position δ _{m (n)} is _equal to the previous steering shaft 83 neutral position δ _{M (n-1)} , the process directly shifts to step H18 and the next steering angle neutral Position learning is performed.

At step H26, the current steering shaft turning position δ _{m (n)}
When it is determined that is not equal to the previous neutral position δ _{M (n-1)} of the steering shaft 83 due to the play of the steering system or the like, the present steering shaft turning position δ _{m (n)} is set in the present embodiment. New steering axis as it is
If the absolute value of these differences is more than the preset correction limit amount Δδ without judging the neutral position δ _{m (n) of} 83, the previous steering axis turning position δ _{m (n-1)} On the other hand, the new neutral position ΔM _{(n) of the} steering shaft 83 is obtained by subtracting or adding the correction limiting amount Δδ, and this is read into the memory in the TCL 76.

In other words, TCL76 indicates the current steering shaft turning position δ _{m (n)} at H27.
It is determined whether or not the value obtained by subtracting the previous neutral position ΔM _(n−1) of the steering shaft 83 from is smaller than a preset negative correction limit amount −Δδ. Then, when it is determined that the value subtracted in step H27 is smaller than the negative correction limit amount −Δδ, the neutral position δ _{M (n)} of the new steering shaft 83 is set to the previous steering at H28. Neutral position of axis 83 ΔM _(n-1) and negative correction limit −Δ
δ is changed to δ _{M (n)} = δ _{M (n-1) −} Δδ, so that the learning correction amount per time does not unconditionally increase to the negative side.

Thus, even an abnormal detection signal from the steering shaft sensor 84 for some reason has been output, is rapidly neutral position [delta] _M of the steering shaft 83 is not changed, it is possible to cope with the abnormality quickly.

On the other hand, when it is determined that the value subtracted in the step of H27 is larger than the negative correction limit amount −Δδ, in H29, the neutral position of the steering shaft 83 from the current steering shaft turning position δ _{m (n)} to the previous steering shaft 83 is neutralized. It is determined whether or not the value obtained by subtracting the position ΔM _(n−1) is larger than the positive correction limit amount Δδ. If it is determined that the value subtracted in step H29 is larger than the positive correction limit amount Δδ, the neutral position _{M (n) of the} new steering shaft 83 is changed in step H30.
Is the neutral position _{M (n-1)} of the previous steering shaft 83 and the positive correction limit Δ
From δ, it is changed to δM _(n) = δM _(n-1) + Δδ, so that the amount of learning correction per time is not unconditionally increased to the positive side.

Thus, even an abnormal detection signal from the steering angle sensor 84 for some reason has been output, is rapidly neutral position [delta] _M of the steering shaft 83 is not changed, it is possible to cope with the abnormality quickly.

However, when it is determined that the value subtracted in step H29 is smaller than the positive correction limit amount Δδ, the current steering shaft turning position δ _{m (n) is set} to the new steering shaft 83 neutral position in H31. δ
Read as it is as _{M (n)} .

Thus, when the present embodiment of learning correcting the neutral position [delta] _M of the steering shaft 83, the rear wheel speed difference | V _RL -V _RR | Besides using only the detection signals from the steering shaft reference position sensor 86 In addition, the neutral position δ _M of the steering shaft 83 can be learned and corrected within a relatively short time after the vehicle 82 starts moving, and the steering shaft reference position sensor 86 fails for some reason. However, the neutral position δ _M of the steering shaft 83 can be learned and corrected only by the rear wheel speed difference | V _RL −V _RR |, which is excellent in safety.

Therefore, when the stopped vehicle 82 starts with the front wheels 64 and 65 kept in the turning state, the neutral position δ of the steering shaft 83 at this time
_As shown in FIG. 7 showing an example of the changing state of _M , the steering shaft 8
3 When the learning control of the neutral position δ _M is the first time, the amount of correction from the initial value δ _{m (o)} of the steering shaft turning position in the step of M1 described above is very large, but the second and subsequent steering axis
The neutral position δ _{M of} 83 is suppressed by the operation in steps H17 and H19.

In this way, after the learning correction of the neutral position [delta] _M of the steering shaft 83, to regulate the driving torque of the engine 11 based on a detection signal from the detection signal and the rear wheel rotation sensor 80, 81 from the front wheel rotation sensor 66 Target drive torque for slip control
Calculate T _OS .

By the way, since 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 , this longitudinal acceleration is used in this embodiment. 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 this longitudinal acceleration G _X is detected by the front wheel rotation sensor 66. The target drive torque T _OS is calculated by making a correction based on a deviation (hereinafter, referred to as a slip amount) s between the speed V _F and the target front wheel speed V _FO corresponding to the vehicle speed V.

As shown in FIG. 8 showing a calculation block for calculating the target drive torque T _OS of the engine 11, first, the TCL 76 determines the vehicle speed V _S for slip control based on the detection signals from the rear wheel rotation sensors 80, 81. In the present embodiment, the low vehicle speed selection unit 101 selects the smaller one of the two rear wheel speeds V _RL and V _RR as the first vehicle speed V _S for slip control and calculates the high vehicle speed. In the selection unit 102, the larger one of the two rear wheel speeds V _RL and V _RR is selected as the second vehicle speed V _S for slip control, and then the changeover switch 103 is used to select one of the two selection units 101 and 102. Further, it is possible to further select which of the outputs in the table is to be captured.

In the present embodiment, the first vehicle speed V _S selected by the low vehicle speed selection unit 101 is set to the smaller value V _L of the two rear wheel speeds V _RL and V _{RR according to} the equation (1). The weighting coefficient K _V corresponding to the calculated vehicle speed V is multiplied by the multiplication unit 104, and the larger value V _H of this and two rear wheel speeds V _RL , V _RR is (1-K _V ).
Is multiplied by the multiplication unit 105 and is added.

That is, the state where the drive torque of the engine 11 is actually reduced by the slip control, that is, the slip control flag F _S
In the set state, the changeover switch 103 selects the smaller one of the two rear wheel speeds V _RL and V _RR as the vehicle speed V _S and drives the engine 11 even if the driver desires slip control. When the torque is not reduced, that is, the slip control flag F _S is reset, the two rear wheel speeds V _RL ,
The larger value of 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, if you select wheel speed V _RL after two during turning of the vehicle 82, a smaller value of the V _RR as a vehicle speed V _S, slip despite slip the front wheels 64 and 65 does not occur Is determined to have occurred, and in order to avoid such a problem that the driving torque of the engine 11 is reduced, and in consideration of the traveling safety of the vehicle 82, the driving torque of the engine 11 is temporarily reduced. This is because consideration has been given to keep this state.

Further, when the vehicle speed V _S is calculated by the low vehicle speed selection unit 101, the smaller value V _L of the two rear wheel speeds V _RL and V _RR is multiplied by the weighting coefficient K _V in the multiplication unit 104. , This and two rear wheel speeds
The larger value V _H of V _RL and V _RR is multiplied by (1-K _V ) 105
Is added to the value obtained by multiplying by the average value of the peripheral speeds of the front wheels 64 and 65 and the two rear wheel speeds V when traveling in a turning circuit with a small radius of curvature such as turning to the left or right at an intersection. _RL , V _RR
Is significantly different from the smaller value _{VL of}
This is because the correction amount of the drive torque due to the feedback is too large and the acceleration of the vehicle 82 may be impaired.

In this embodiment, the weighting coefficient K _{V is set} to the rear wheels 78,7.
The map is read out from the map shown in FIG. 9 based on the vehicle speed V of the equation (1), which is the average value of the peripheral speeds of 9.

The longitudinal acceleration G _X is calculated based on the slip control vehicle speed V _S thus calculated.First, the vehicle speed V _{S (n)} calculated this time and the vehicle speed V _{S (n-1 )} And the current longitudinal acceleration G _{X (n)} of the vehicle 82 is calculated by the differential calculation unit 106 as in the following equation.

However, Δt is the sampling period of this control, which is 15 milliseconds, and g is the acceleration of gravity.

If the calculated longitudinal acceleration G _{X (n)} is 0.6 g or more, the maximum value of this longitudinal acceleration G _{X (n)} does not exceed 0.6 g in consideration of safety against calculation errors. like,
The clip portion 107 clips the longitudinal acceleration G _{X (n)} to 0.6 g. Further, the filter unit 108 performs filter processing for noise removal to calculate the corrected longitudinal acceleration G _XF .

This filtering, since the longitudinal acceleration G _X of the vehicle 82 _(n) can be regarded to be equivalent to the friction coefficient between the tire and the road surface, the maximum value of the longitudinal acceleration G _{X (n)} and change in vehicle 82 Even if the slip rate S of the tire is likely to deviate from the target slip rate S _O corresponding to the maximum value of the friction coefficient between the tire and the road surface or the vicinity thereof, the slip rate S of the tire S
To correct the longitudinal acceleration G _{X (n)} so as to maintain the target slip ratio S _O corresponding to the maximum value of the coefficient of friction between the tire and the road surface or a smaller value in the vicinity thereof. Specifically, it is performed as follows.

If the current longitudinal acceleration G _{X (n)} is greater than or _equal to the filtered previous longitudinal acceleration G _{XF (n-1)} , that is, when the vehicle 82 continues to accelerate, the current longitudinal acceleration G _{XF (n )} As a result, noise is removed by delay processing, and the corrected longitudinal acceleration G _{XF (n)} follows the longitudinal acceleration G _{X (n)} relatively quickly.

This longitudinal acceleration G _{X (n)} is the previous corrected longitudinal acceleration G
_When it is less than _{XF (n-1)} , that is, when the vehicle 82 is not accelerating too much, the following processing is performed every sampling period Δt of the main timer.

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

Further, 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, when the front wheels 64 and 65 are slightly slipped, the vehicle 82 is decelerating and therefore safety is ensured. Since G _{XF (n)} = G _{XF (n−1)} −0.002, the corrected longitudinal acceleration G _XF is prevented from decreasing and the responsiveness to the driver's request for acceleration of the vehicle 82 is 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 held, The responsiveness to the driver's request for acceleration of the vehicle 82 is ensured.

Similarly, when the hydraulic control device 16 shifts up the hydraulic automatic transmission 13 while the drive torque of the engine 11 is reduced by the slip control, it is necessary to secure a feeling of acceleration for the driver, and the corrected longitudinal acceleration Holds the maximum value of G _XF .

Then, 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, but the value calculated by this torque conversion unit 109 is naturally a positive value. Since it should be a value, the clipping unit 110 clips this to 0 or more in order to prevent a calculation error, and then the running resistance T _R calculated by the running resistance calculation unit 111 is added by the addition unit 112. Then, the cornering drag correction torque T _C calculated by the cornering drag correction amount calculation unit 113 based on the detection signal from the steering angle sensor 84 is added by the addition unit 114, and the reference drive shown in the following formula (4) is performed. Calculate the torque T _B.

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 traveling resistance T _R can be calculated as a function of the vehicle speed V, but in the present embodiment, it is obtained from the map shown in FIG. In this case, the running resistance at the flat road and an uphill road T _R
Therefore, in the figure, for the flat road shown by the solid line and for the uphill road shown by the two-dot chain line are written in the map, based on the detection signal from the tilt sensor (not shown) incorporated in the vehicle 82, Although either one is selected, it is possible to further finely set the traveling resistance T _R including a downhill or the like.

Further, in the present embodiment, the cornering drag correction torque T _C is obtained from a map as shown in FIG. 11, whereby a reference driving torque T _B of the engine 11 which is similar to the actual running state can be set. 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.

The reference drive torque calculated by the equation (4)
In the present embodiment, the lower limit value is set by the variable clip unit 115 for T _{B, so} that a value obtained by subtracting a final correction torque T _PID described later from the reference drive torque T _B by the subtraction unit 116 is negative. This prevents problems that would otherwise occur. As shown in the map shown in FIG. 12, 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 as described above, is set based on the front wheel speed V _F and the vehicle speed V _S for slip control. By performing feedback control of the reference drive torque T _B using a slip amount s that is a deviation from the target front wheel speed V _FS for correction torque set based on the target front wheel speed V _FO Calculate the driving torque T _OS .

By the way, in order to make effective use of the drive torque generated in the engine 11 during acceleration of the vehicle 82, as shown by the solid line in FIG. 13, the slip ratio S of the tires of the front wheels 64, 65 during traveling is
Is adjusted so that the maximum value of the coefficient of friction between the tire and the road surface and the corresponding target slip ratio S _o or a value near the target slip ratio S 0 are smaller than these values to avoid energy loss and control performance and acceleration of the vehicle 82. It is desirable not to impair performance.

Here, the target slip ratio S _O is 0.1 depending on the road surface condition.
It is known that the vehicle swings in the range of about 0.25. Therefore, it is desirable to generate the slip amount s of about 10% with respect to the road surface on the front wheels 64 and 65 as the driving wheels while the vehicle 82 is traveling. In consideration of the above points, the target front wheel speed V _FO is set by the multiplying 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 shown in FIG. 14 in the acceleration correction unit 118, and uses this as the reference in the addition unit 119. Add to target front wheel speed V _FO for torque calculation. The slip correction amount V _K has a tendency to increase stepwise as the value of the corrected longitudinal acceleration G _XF increases, but in this embodiment, this map is created based on a running test or the like. There is.

As a result, the target front wheel speed V _FS for correction torque calculation is increased, and the slip ratio S during acceleration is set to a value smaller than the target slip ratio S _O shown by the solid line in FIG. 13 or in the vicinity thereof. To be done.

On the other hand, the coefficient of friction between the tire and the road surface during turning,
As shown by the alternate long and short dash line in FIG. 13 with respect to the tire slip ratio S, the tire slip ratio, which is the maximum friction coefficient between the tire and the road surface during turning, is It can be seen that the friction coefficient is significantly smaller than the target slip ratio S _{O of the} tire, which is the maximum value. Therefore, it is desirable to set the target front wheel speed V _FO smaller than that when the vehicle is straight ahead so that the vehicle 82 can smoothly turn while 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 as shown by the solid line in FIG. 15, and the subtraction unit 121 reads it out from the target front wheel speed V for calculating the reference torque. Subtract from _FO . However, until the first neutral position δ _M of the steering shaft 83, which is performed after the ignition key switch 75 is turned on, is learned.
Since the turning angle δ _H is not reliable, the peripheral speed V of the rear wheels 78 and 79 is
Based on the lateral acceleration G _Y actually acting on the vehicle 82 by _RL and V _RR , the slip correction amount V _KC is read from the map as shown by the broken line in FIG.

By the way, the target lateral acceleration G _YO is calculated by the formula (2) based on the detection signal from the steering angle sensor 84, and is calculated by the formula (3) using the steering angle δ. The neutral position δ _{M of} 83 is learned and corrected.

Therefore, the steering angle sensor 84 or the steering axis reference position sensor 86
If an abnormality occurs in the target lateral acceleration G _YO, it is possible that the target lateral acceleration G _YO will be a completely incorrect value. Therefore, when an abnormality occurs in the steering angle sensor 84 or the like, the actual lateral acceleration G _Y generated in the vehicle 82 is calculated using the rear wheel speed difference | V _RL −V _RR |, and this is calculated as the target lateral acceleration. _Used in place of G _YO .

Specifically, this actual lateral acceleration G _Y is the rear wheel speed difference | V _RL
-V _RR | and the vehicle speed V are calculated by the lateral acceleration calculation unit 122 incorporated in the TCL76 according to the following equation (5), and the corrected lateral acceleration G _{YF is obtained} by noise removal processing by the filter unit 123.
Is used.

However, b is the tread of the rear wheels 78 and 79, and the filter unit 123 uses the lateral acceleration G _{Y (n)} calculated this time and the corrected lateral acceleration G _{YF (n-1)} calculated last time to correct the lateral acceleration of this time. G _{YF (n)}
The low-pass processing is performed by the digital calculation shown in the following equation.

Whether or not an abnormality has occurred in the steering angle sensor 84 or the steering shaft reference position sensor 86 can be detected by the TCL 76 by a disconnection detection circuit or the like shown in FIG. 16, for example. That is, the outputs of the steering angle sensor 84 and the steering axis reference position sensor 86 are pulled up by the resistor R and grounded by the capacitor C, and the outputs are directly input to the A0 terminal of the TCL76 and used for various controls. It is input to the A1 terminal through the comparator 88. A specified value of 4.5 V is applied as a reference voltage to the negative terminal of the comparator 88, and when the steering angle sensor 84 is disconnected, the input voltage at the A0 terminal exceeds the specified value and the comparator 88 turns on and the A1 terminal The input voltage continues to be high level H. Therefore, if the input voltage of the A1 terminal is at a high level H for a certain period of time, for example, 2 seconds, the program of the TCL76 is determined so as to judge that the wire is broken and detect the occurrence of an abnormality in the steering angle sensor 84 or the steering axis reference position sensor 86. It is set.

In the embodiment described above, the steering angle sensor is implemented by hardware.
Although the abnormality such as 84 is detected, it is naturally possible to detect the abnormality by software.

For example, as shown in FIG. 17 showing an example of this abnormality detection procedure, TCL76 first determines the abnormality by the disconnection detection shown in FIG. 16 at W1, and if it is determined that it is not abnormal, Front wheel rotation sensor 66 and rear wheel rotation sensor 8 at W2
It is determined whether or not 0 and 81 are abnormal. When it is determined that there is no abnormality in each rotation sensor 66, 80, 81 in the step of W2, the steering shaft 83 makes one rotation or more in the same direction at W3, for example,
It is judged whether or not the steering wheel is steered 400 degrees or more. If it is determined in this step W3 that the steering shaft 83 has been steered by 400 degrees or more in the same direction, whether or not there is a signal from the steering shaft reference position sensor 86 which notifies the reference position δ _N of the steering shaft 83 in W4. To judge.

Then, in this step of W4, the reference position δ of the steering shaft 83
If it is determined that there is no signal that notifies _N , and the steering shaft reference position sensor 86 is normal, the reference position δ of the steering shaft 83
There should be at least one signal that signals _N , so W
At 4, it is determined that the steering angle sensor 84 is abnormal, and at W9, the abnormality occurrence flag F _W is set.

When it is determined in step W3 that the steering shaft 83 is not steered in the same direction by 400 degrees or more, or in step W4, a signal notifying the reference position δ _N of the steering shaft 83 is output from the steering shaft reference position sensor 86. If it is determined that the neutral position δ _M has been learned in W5, that is, whether at least one of the two steering angle neutral position learned flags F _HN , F _H is set. To determine.

Then, in this step of W5, the neutral position of the steering shaft 83 δ _M
If it is determined that learning has been completed, the rear wheel speed difference | V _RL −V _RR | exceeds, for example, 1.5 km / h at W6, and the vehicle speed V is, for example, between 20 km / h and 60 km / h at W7. And the absolute value of the turning angle δ _H of the steering shaft 83 at this time is less than 10 degrees in W8, that is, when it is determined that the vehicle 82 is turning at a certain speed, the steering angle If the sensor 84 is functioning normally, the absolute value of the turning angle δ _H should be 10 degrees or more, so it is determined that the steering angle sensor 84 is abnormal at W9, and the abnormality flag is generated. Set Fw.

It should be noted that the slip correction amount V _KC corresponding to the target lateral acceleration G _YO may correspond to the corrected lateral acceleration G _YF in a region where the target lateral acceleration G _YO is small, because the steering wheel 85 of the driver may be increased. The slip correction amount V _KC is set to a smaller value. If the vehicle speed V is low,
It is desirable to secure the acceleration of 82, and conversely this vehicle speed V
When the speed is above a certain level, it is necessary to consider the ease of turning, so the slip correction amount read from Fig. 15
The corrected slip correction amount V _KF is calculated by reading V _KC and a correction coefficient corresponding to the vehicle speed V from the map shown in FIG. 18 and multiplying it.

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 running, and the acceleration performance of the vehicle 82 slightly deteriorates, but good turning is achieved. Sex is secured.

As shown in FIG. 19 showing the procedure for selecting the target lateral acceleration G _YO and the actual lateral acceleration G _Y , the TCL76 is a lateral acceleration for calculating the slip correction amount V _KC at T1 from the filter unit 123. The corrected lateral acceleration G _YF is adopted and 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 adopted as is. This is because when the lateral acceleration, which is the reference for determining the slip correction amount V _KC during slip control, is changed from the corrected lateral acceleration G _YF to the target lateral acceleration G _YO , the slip correction amount V _KC changes greatly and the vehicle 82 This is because there is a possibility that the behavior of is disturbed.

If step at the slip control flag F _S of the T2 is determined not to be set, the two steering angle neutral position learned F _HN at T3, or either one of the F _H is set Determine whether or not. Here, 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. If it is determined at step T3 that any of the two steering angle neutral position learned flags F _HN and F _H has been set, the slip correction amount V _KC is calculated at T4. The target lateral acceleration G _YO is adopted as the lateral acceleration of.

As a result, the target front wheel speed V _FS for correction torque calculation is given by the following equation.

V _FS = V _FO + V _K −V _F Next, 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 noise removal and the target front wheel speed V _FS for calculating the correction torque. The subtraction unit 124 calculates the slip amount s, which is the deviation from When the slip amount s is less than or equal to a negative set value, for example, −2.5 km / h or less, −2.5 km / h is clipped by the clip unit 125 as the slip amount s, and the slip amount s after the clipping process is set. On the other hand, a proportional correction which will be described later is performed 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 using a later-described integral constant ΔT _i on the slip amount s before the clipping process and further performing differential correction.

As the proportional correction, the slip amount s
Is multiplied by a proportional coefficient K _P to obtain a basic correction amount, and the multiplication unit 127 further multiplies the correction coefficient ρ _KP preset by the gear ratio ρ _{m of the} hydraulic automatic transmission 13 to obtain the proportional correction torque T. I'm getting _P. The proportional coefficient K _P is read from the map shown in FIG. 20 according to the slip amount s after the clipping process.

In addition, in order to realize a correction corresponding to a gradual change in the slip amount s as the integral correction, a basic correction amount is calculated by the integration operation unit 128, and this correction amount is multiplied by the multiplication unit 12
At 9, the integral correction torque T _I is obtained by multiplying the preset correction coefficient ρ _KI based on the gear ratio ρ _m of the hydraulic automatic transmission 13. In this case, in the present embodiment, a constant small integral correction torque ΔT _I is integrated, and if the slip amount s is positive every 15 ms sampling period, the minute integral correction torque ΔT _I is added, and the inverse If the slip amount s is negative, the minute integral correction torque ΔT _I is subtracted.

However, the integral correction torque T _I may be clipped at a constant value, but a lower limit value T _IL as shown in the map of FIG. 21 which is variable according to the vehicle speed V is set. At the time of starting, especially when starting uphill, a large integral correction torque T _I is applied to secure the driving force of the engine 11, and after the vehicle speed V increases after starting the vehicle 82, conversely, if the correction is too large, control is performed. The integration correction torque T _I
Is small. 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 clip processing 22
It changes as shown in the figure.

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

The correction factors ρ _KP and ρ _KI are the hydraulic automatic transmission 13
The map shown in FIG. 23 is read out in association with the gear ratio ρ _m .

Further, in this embodiment calculates a change rate G _s of the slip amount s by differentiating unit 131, which in multiplied by the differential coefficient K _D in multiplication unit 132, basic correction for sudden change in slip amount s Calculate the amount. Then, the upper limit value and the lower limit value are respectively set to the values obtained by this, and clipping processing is performed by the clipping unit 133 so that the differential correction torque T _D does not become an extremely large value. I'm getting _D. The clip portion 133 is _{designed to reduce} wheel speeds V _F , V _RL , V while the vehicle 82 is traveling.
_RR may momentarily become idling or locked depending on the road surface condition, the traveling state of the vehicle 82, etc. In such a case, the change rate G _s of the slip amount _s becomes a positive or negative extremely large value, Since the control may diverge and the responsiveness may decrease, for example, the lower limit value is clipped to −55 kgm and the upper limit value is clipped to 55 kgm so that the differential correction torque T _D does not become an extremely large value. It is a thing.

Then, the adder unit 134 adds the proportional-integral correction torque T _PI and the derivative correction torque T _D, and the final correction torque T _PID obtained by this is subtracted from the reference drive torque T _B by the subtractor unit 116. Then, the multiplication unit 135 further multiplies the reciprocal of the total reduction ratio between the engine 11 and the axles 89, 90 of the front wheels 64, 65 to obtain the target drive torque T for slip control shown in the following equation (6). Calculate the _OS .

However, 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 gear shifting operation, the gear ratio ρ on the high speed stage side after the gear shifting is completed.
_m is output. That is, in the case of an upshift gear shifting operation of the hydraulic automatic transmission 13, if the gear ratio ρ _m on the high speed stage side is adopted at the time of outputting the gear shift signal, as is clear from the above equation (6), Since the target drive torque T _OS increases and the engine 11 blows up during this,
After the gear change operation is completed after the gear change start signal is output, for example, for 1.5 seconds, the gear ratio ρ _m on the low speed stage side that can reduce the target drive torque T _OS is held, and after the gear change start signal is output. After 1.5 seconds, the gear ratio ρ _m on the high speed side is adopted. 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.

As described above, the torque correction by the proportional control mainly plays a role of lowering the target drive torque so as not to cause too much slip by clipping the slip amount s at the lower limit value when calculating the proportional correction torque T _P. Instead, the torque correction by the integral control mainly plays a role of increasing the target drive torque so as to cause the slip by clipping the integral corrected torque T _I at the upper limit value. However, as described above, the clip value T _IL on the lower limit side of the integral correction torque T _I is variable depending on the vehicle speed as shown in FIG. 21, so a large correction works at low speed to secure the driving force necessary for starting uphill roads. However, after starting, the correction becomes small and the control becomes stable.

Since the target drive torque T _OS calculated by the equation (6) should be a positive value as a matter of course, the clip portion
In 136, the target drive torque T _OS is clipped to 0 or more for the purpose of preventing a calculation error, and the target drive torque T _OS is determined according to the determination processing in the start / end determination unit 137 for determining the start or end of the slip control. Information about the _OS is output to ECU15.

The start / end determination unit 137 determines that the slip control is to be started when all the conditions (a) to (e) below are satisfied, sets the slip control in-progress flag F _S, and outputs from the low vehicle speed selection unit 101. The selector switch 103 is operated to select the output as the vehicle speed V _S for slip control, information about the target drive torque T _OS is output to the ECU 15, and the slip control in-progress flag F _S is reset when the end of slip control is judged. This process is continued until.

(A) The driver desires slip control by operating a manual switch (not shown).

(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 or more.

In the present embodiment, the required drive torque T _d is the engine speed calculated from the detection signal from the crank angle sensor 62.
_A second preset value based on N _E and the accelerator opening θ _A calculated from the detection signal from the accelerator opening sensor 76.
It is read from the map as shown in Fig. 4.

(C) The slip amount s is 2 km or more per hour.

(D) The change rate G _s of the slip amount _s is 0.2 g or more.

(E) The actual front wheel acceleration G _{F, which} is the time differential of the actual front wheel speed V _F in the differential calculation unit 138, is 0.2 g or more.

On the other hand, after the start / end determination unit 137 determines that the slip control is started, if either of the following conditions (f) and (g) is satisfied, it is determined that the slip control is completed and the slip control is completed. The control flag F _S is reset, the transmission of the target drive torque T _OS to the ECU 15 is stopped, and the changeover switch 103 is operated so as to select the output from the high vehicle speed selection unit 102 as the vehicle speed V _S for slip control.

(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 / hour or less for a certain time, for example, 0.5 seconds or more.

(G) The state in which the idle switch 68 is changed from off to on, that is, the state in which 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, and when the driver operates the manual switch to select the slip control, the slip control of the slip control described below is performed. Do the operation.

As shown in FIG. 25 showing the flow of this slip control processing, the TCL75 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 the manual switch. It is performed regardless of the operation of.

Then, first, the slip control flag F _S at S2 is determines whether it is set, because the first slip control flag F _S is not set, TCL76 is in S3 front wheel 6
The slip amount s of 4,65 is a preset threshold value, for example, 2 k / h
Determine if it is greater than m.

If 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.

When it is determined in step S4 that the slip amount change rate G _s is larger than 0.2 g, the TCL76 determines in S5 that the driver's required drive torque T _d is the minimum drive torque required to drive the vehicle 82, for example, Whether or not it is larger than 4 kgm, that is, whether or not the driver intends to drive the vehicle 82 is determined.

If it is determined in step S5 that the required drive torque T _d is larger than 4 kgm, that is, the driver intends to drive the vehicle 82, the slip control flag F _S is set in step S6, and the slip is set in step S7. It is again determined whether or not the control flag F _S is set.

When it is determined in step S7 that the slip control flag F _S is being set, the target drive torque T _OS of the engine 11 is calculated in advance in S8 as the slip control flag F _S for slip control. Adopt target drive torque T _OS .

If it is determined in step S7 that the slip control flag F _S has been reset, TCL76 is set in step S9.
Outputs the maximum torque of the engine 11 as the target drive torque T _OS , whereby 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 operates the accelerator pedal 31 of the driver. Drive torque is generated according to the amount of depression.

If it is determined in step S3 that the slip amount s of the front wheels 64, 65 is less than 2 km / h, or if the slip amount change rate G _s is less than 0.2 g in step S4, or At step S5, the required drive torque T _d
If it is judged to be smaller than 4 kgm, S7
In step S9, the TCL 76 outputs the maximum torque of the engine 11 as the target drive torque T _OS , whereby the ECU 15 lowers the duty ratio of the torque control solenoid valves 51 and 56 to the 0% side. As a result, 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, in the step S2, the slip control flag F _S
If it is determined that is set, the front wheel 6 at S10
It is determined whether the state where the slip amount s of 4,65 is equal to or less than the threshold value of −2 km / hour and the required drive torque T _d is equal to or less than the target drive torque T _OS calculated in S1 is continued for 0.5 seconds or more. To do.

In this step of S10, the state where 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 continues for 0.5 seconds or more, that is, the driver
If it is determined that the acceleration of No. has not been desired, the slip control flag F _S is reset in S11, and the process proceeds to step S7.

In the step S10, the slip amount s is larger than 2 km / h, or the required drive torque T _d is the target drive torque T
_{If the} driver determines that the state below _OS is not maintained for 0.5 seconds or more, that is, the driver wants to accelerate the vehicle 82, the TCL76 sets S
At 12, the idle switch 68 is turned on, that is, the throttle valve 20
It is determined whether the fully closed state has continued 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 other hand, 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 TCL76 calculates the target drive torque T _OS for the slip control as described above, and then the engine 11 when the turning control is performed. Calculate the target drive torque.

By the way, the lateral acceleration G _Y of the vehicle 82 is the rear wheel speed difference | V _RL −V _RR
Although it can be actually calculated by the equation (5) using |, by using the steering shaft turning angle δ _H ,
Since the value of the lateral acceleration G _Y acting on the vehicle 82 can be predicted, there is an advantage that quick control can be performed.

Therefore, when controlling the turning of the vehicle 82, the TCL 76 determines the target lateral acceleration G _{YO of the} vehicle 82 from the steering axis turning angle δ _H and the vehicle speed V.
Is calculated by the above equation (3), and the acceleration in the vehicle front-rear direction so that the vehicle 82 does not undergo excessive understeering,
That is, the target longitudinal acceleration G _XO is set based on this target lateral acceleration G _YO . Then, the target drive torque T _OC of the engine 11 corresponding to this target longitudinal acceleration G _XO is calculated.

As shown in FIG. 26 showing the calculation block of this turning control, the TCL 76 uses a pair of rear wheel rotation sensors 8 in the vehicle speed calculation unit 140.
The vehicle speed V is calculated from the output of 0,81 by the equation (1), and the front wheels 64,6 based on the detection signal from the steering angle sensor 84.
The steering angle δ of 5 is calculated from the equation (2), and the target lateral acceleration computing unit 141 calculates the target lateral acceleration G _YO of the vehicle 82 at this time from the equation (3). In this case, when the vehicle speed V is small, for example, 22.5 km / h or less, it is better to prohibit turning control than to perform turning control, for example, to obtain sufficient acceleration when turning left or right at an intersection with heavy traffic. Since it is often convenient in terms of safety, in the present embodiment, the correction coefficient multiplication unit 142 sets the correction coefficient K _Y as shown in FIG. 27 to the target lateral acceleration G _YO according to the vehicle speed V. Multiplying.

By the way, in a state where the steering shaft neutral position δ _M is not learned, there is a problem in reliability in calculating the target lateral acceleration G _YO based on the steering angle δ. It is desirable not to start the turning control until the axis neutral position δ _M is learned. However, when the vehicle 82 travels on a curved road immediately after the start of traveling, the vehicle 82 is in a state in which turning control is required.
_Since the learning start condition of _M is not easily satisfied, there is a possibility that this turning control is not started. Therefore, in this embodiment, until the steering shaft neutral position δ _M is learned, the changeover switch 143 can perform the turning control by using the corrected lateral acceleration G _YF from the filter unit 123 based on the equation (5). I have to. That is, when both of the two steering angle neutral position learned flags F _HN and F _H are reset, the correction lateral acceleration G _YF is changed by the changeover switch 143.
If at least one of the two steering angle neutral position learned flags F _HN and F _H is set, the changeover switch 143 is used to set the target lateral acceleration G from the correction coefficient multiplication unit 142.
_YO is selected.

Further, the stability factor A described above is a value determined by the configuration of the suspension system of the vehicle 82, the characteristics of the tires, the road surface condition, etc., as is well known. 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 _HO of the steering shaft 83 at this time (the neutral position δ _{M of the} steering shaft 83).
The ratio of the turning angle δ _HO of the steering shaft 83 in the extremely low speed traveling state in which the lateral acceleration G _Y is close to 0 with respect to the ratio of the turning angle δ _H of the steering shaft 83 during acceleration) 28
It is expressed as the slope of the tangent in the graph shown in the figure. That is, in the lateral acceleration G _Y is not very high vehicle speed V small area, but the stability factor A is almost constant value (A = 0.002), the lateral acceleration G _Y exceeds 0.6 g, stability Factor A increases sharply, causing vehicle 82 to exhibit a very strong tendency to understeer.

From the above, the paved road surface in the dry state (hereinafter,
(This is called the high μ road) Based on FIG. 28 corresponding to the high μ road, set the stability factor A to 0.002,
The target lateral acceleration G _{YO of the} vehicle 82 calculated by the equation (3) is
The drive torque of the engine 11 is controlled so as to be less than 0.6 g.

In the case of a slippery road surface such as a frozen road (hereinafter referred to as a low μ road), the stability factor A may be set to about 0.005. in this case,
On low μ roads, the target lateral acceleration G _YO is larger than the actual lateral acceleration G _Y, so whether the target lateral acceleration G _YO is larger than a preset threshold value, for example (G _YF -2). If 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 corrected lateral acceleration G _YF calculated based on the equation (5) is 0.0
Whether the target lateral acceleration G _YO than a preset threshold value by adding 5g is large, that is because 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 It is determined whether the lateral 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.

After calculating the target lateral acceleration G _YO in this way,
The target longitudinal acceleration G _XO of the vehicle 82 set in advance according to the magnitude of the target lateral acceleration G _YO and the vehicle speed V is stored in the TCL 76 by the target longitudinal acceleration calculating unit 144 from the map as shown in FIG. 29. The reference drive torque T _B of the engine 11 corresponding to this target longitudinal acceleration G _XO is read out and the reference drive torque calculation unit is read out.
It is calculated by the following equation (7) at 145.

However, T _L is the lateral acceleration G _Y resistance of the road surface which is determined as a function of road load (Road-Load) torque of the vehicle 82, in this embodiment, are calculated from the map as shown in FIG. 30.

Here, according to the steering shaft turning angle δ _H and the vehicle speed V, the engine 1
If only the target drive torque of 1 is obtained, the driver's will will not be reflected at all, and the driver may be dissatisfied with respect to the maneuverability of the vehicle 82. For this reason, the driver's desired engine 11
Seeking the requested driving torque T _d from the depression amount of the accelerator pedal 31, it is desirable to set the target drive torque of the engine 11 in consideration of the required driving torque T _d.

Therefore, in the present embodiment, in order to determine the adoption ratio of the reference drive torque T _B , the multiplying unit 146 multiplies the reference drive torque T _B by the weighting coefficient α to obtain the corrected reference drive torque.
This weighting coefficient α is set empirically by turning the vehicle 82, but on a high μ road, a value around 0.6 is adopted.

On the other hand, the required drive torque T _d desired by the driver 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 is shown in FIG. 29. Obtained from the map as shown, then multiplying unit 14
In step 7, the correction request drive torque corresponding to the weighting coefficient α is calculated by multiplying the request drive torque T _d by (1-α). For example, when α = 0.6 is set,
The adoption ratio of the standard drive torque T _B and the required drive torque T _d is 6
It becomes pair 4.

Therefore, the target drive torque T _OC of the engine 11 is calculated by the addition unit 148 by the following equation (8).

T _OC = α ・ T _B + (1-α) ・ T _d (8) By the way, if the increase / decrease in the target drive torque T _OC of the engine 11 set every 15 milliseconds is very large, Since a shock occurs due to the acceleration / deceleration of 82, which leads to a reduction in riding comfort, if the increase / decrease in the target drive torque T _OC of the engine 11 becomes large enough to cause a reduction in the riding comfort of the vehicle 82, It is desirable to regulate the increase / decrease amount of this target drive torque T _OC .

Therefore, in the present embodiment, 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 by the change amount clipping unit 149 is allowed to increase or decrease. If it is smaller than the capacity T _K , the calculated current target drive torque
Although T _{OC (n)} is adopted as it 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 more than the negative increase / decrease allowable amount T _K. If not big,
The target drive torque T _{OC (n)} this time is set by the following formula.

T _{OC (n)} = T _{OC (n-1)} −T _K That is, the drive torque of the engine 11 is reduced by restricting the amount of decrease with respect to the target drive torque T _{OC (n-1)} calculated last time by the increase / decrease allowable amount T _K. Reduce the deceleration shock caused by. Further, the target drive torque T _{OC (n)} calculated this time and the target drive torque calculated above
When the difference ΔT from T _{OC (n-1)} is _equal to or larger than the increase / decrease allowable amount T _K , the target drive torque T _{OC (n)} at this time is set by the following formula.

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.
If T _K is exceeded, the previously calculated target drive torque T
_The increase range for _{OC (n-1)} is regulated by the allowable increase / decrease amount T _K , and the engine 1
Reduces the acceleration shock that accompanies the increase in drive torque of 1.

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

The start / end determination unit 150 determines that the turning control is started when all the conditions (a) to (d) below are satisfied,
Target drive torque with turning control flag F _C set
Information about T _OC output to ECU 15, the turning control flag F _C to determine the end of the turning control until the reset, and this process is continued.

(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 desires turning control by operating a manual switch (not shown).

(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 and the turning is ended. The in-control flag F _C is reset and the transmission of the target drive torque T _OC to the ECU 15 is stopped.

(E) The target drive torque T _OS is greater than or _equal to the required drive torque T _d .

(F) There is an abnormality such as a failure or disconnection in the control system for turning.

By the way, there is, of course, a constant proportional relationship between the output voltage of the accelerator opening sensor 77 and the accelerator opening θ _A , and when the accelerator opening θ _A is fully closed, the accelerator opening sensor 77 The accelerator opening sensor 77 is attached to the throttle body 21 so that the output voltage becomes 0.6 V, for example.
Is assembled. However, when the accelerator opening sensor 77 is detached from the throttle body 21 for inspection and maintenance of the vehicle 82 and reassembled, it is practically impossible to accurately return the accelerator opening sensor 77 to the original mounting state. This is possible, and there is also a risk that the position of the accelerator opening sensor 77 with respect to the throttle body 21 may shift due to secular change or the like.

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

As shown in FIG. 31 showing the learning procedure of 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 ECU 15 or The output of the accelerator opening sensor 77 is monitored for 2 seconds in which the operation of the TCL76 is guaranteed, and the minimum value of the output of the accelerator opening sensor 77 during this period is taken in as the fully closed position of the accelerator opening θ _A and incorporated into the ECU 15. R with backup not shown
It is stored in AM and the accelerator opening θ _A is corrected until the next learning with the lowest value of the output of the accelerator opening sensor 77 as a reference.

However, when the storage battery (not shown) mounted on the vehicle 82 is removed, the storage of the RAM is erased.
In such a case, the learning procedure shown in FIG. 32 is adopted.

In other words, TCL76 is the closed value θ _AC of accelerator opening θ _A at A1.
Is stored in the RAM, and if it is determined in step A1 that the fully closed value θ _AC of the accelerator opening θ _A is not stored in RAM, the initial value is set in A2. θ _{A (O)}
Is stored in RAM.

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 RAM, A3
At, it is determined whether or not the ignition key switch 75 is in the ON state. If it is determined in step A3 that the ignition key switch 75 has changed from the ON state to the OFF state, the learning timer (not shown) starts counting in A4. After the learning timer starts counting, it is determined at A5 whether the idle switch 68 is in the on state.

If it is determined in step A5 that the idle switch 68 is off, it is determined in step A6 whether or not the count of the learning timer reaches a set value, for example, 2 seconds,
Return to step A5 again. Further, when it is determined that the idle switch 68 is in the ON state in step A5, the output of the accelerator opening sensor 77 is read at a predetermined cycle at A7, and the current accelerator opening θ _{A ( It} is determined whether _n) is smaller than the minimum value θ _AL of the accelerator opening θ _A so far.

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 value theta _AL accelerator opening theta _A far If it is judged that the accelerator opening θ _{A (n)} of this time is smaller than the minimum value θ _AL of the accelerator opening θ _A so far, the current accelerator opening θ _A Update _{A (n)} as a new minimum value θ _AL . This operation is repeated in step A6 until the count of the learning timer reaches a set value, for example, 2 seconds.

If the learning timer count reaches the set value, A1
At 0, it is determined whether or not the minimum value θ _AL of the accelerator opening θ _A is a preset clip value, for example, between 0.3 volt and 0.9 volt. 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 of the accelerator opening θ _A is set at A11.
_{A (O)} or the fully closed value θ _AC that is brought closer to a constant value in the direction of the minimum value θ _AL , for example, 0.1 volt, is set as the fully closed value θ _{AC (n)} of the accelerator opening θ _A by the current learning. That is, when the initial value θ _{A (O)} or the fully closed value θ _{AC of} the accelerator opening θ _A is larger than its minimum value θ _AL , θ _{AC (n)} = θ _{A (O)} −0.1 or θ Set _{Ac (n)} = θ _{AC (n-1)} −0.1, and conversely, if the initial value θ _{A (O)} of the accelerator opening θ _A or the fully closed value θ _AC is larger than its minimum value θ _AL. Is set to θ _{Ac (n)} = θ _{A (O)} +0.1 or θ _{Ac (n)} = θ _{AC (n-1)} +0.1.

In the step A10, the minimum value of the accelerator opening θ _A θ _AL
When it is determined that is outside the range of the preset clip value, the clip value of the one outside A12 is replaced as the minimum value θ _AL of the accelerator opening θ _A , and the process proceeds to step A11. Learn correction of fully closed value θ _AC of accelerator opening θ _A.

Thus, by setting the upper limit value and the lower limit value to the minimum value θ _AL of the accelerator opening θ _A , the accelerator opening sensor
Even if 77 fails, there is no risk of erroneous learning, and by setting the learning correction amount per time to a fixed value, erroneous learning will not occur even for disturbances such as noise.

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.
Using a seating sensor incorporated in a seat (not shown), it is detected that the driver has left the seat even when the ignition key switch 75 is in an on state by using a seat pressure change or position displacement by the seating sensor. The learning process after the step may be started. Further, when it is detected that the door lock device (not shown) is operated from the outside of the vehicle 82 or the door lock device is operated by the key entry system, the fully closed value of the accelerator opening sensor 77 is detected. It is also possible to start learning θ _AC . In addition to this, the position of the shift lever (not shown) of the hydraulic automatic transmission 13 is the neutral position or the parking position (the neutral position in the case of a vehicle equipped with a manual transmission), the manual brake is operated, and The learning process may be performed when the air conditioner is off, that is, not in the idle-up state.

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, the turning control described below is performed. It is designed to operate.

As shown in FIG. 33 showing the flow of control for determining the target drive torque T _OC for turning control, the target drive torque T _OC is calculated by the various data detection and arithmetic processing described above at C1. However, this operation is performed irrespective 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 C3, for example (T _d
-2) It is determined whether or not the following. That is, the target drive torque T _OC can be calculated even when the vehicle 82 is traveling straight,
The value is usually larger than the driver's required driving torque _Td . However, since the required drive torque T _d is generally small when the vehicle 82 turns, the target drive torque T _OC
Is determined as the start condition of the turning control when the value becomes equal to or less than the threshold value (T _d -2).

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

At the step of C3, the target drive torque T _OC is the threshold value (T _d −
2) When it is determined that the following is true, the TCL 76 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 reliability of the steering angle δ detected by the steering angle sensor 84. To be done.

Two rudder angle neutral position learned flag F in step C6
_HN, when at least one of the F _H is determined to be set, whether the turning control flag F _C is set at C7 is determined again.

In the above procedure, the turning control flag is set in step C5.
Since F _C is set, it is determined that the turning control flag F _C is set in the step C7, and the previously calculated value in C8, that is, the target drive torque T _{OC in} the step C1 is directly adopted. To be done.

On the other hand, if it is determined in step C6 that none of the steering angle neutral position learned flags F _HN and F _H has been set, it is determined whether the turning control flag F _C has been set in C17. Is determined again. If it is determined in step C17 that the turning control flag F _C is set,
Although the process shifts to the step of C8, since the steering angle δ calculated by the formula (2) is not _reliable , the target driving torque of the formula (8) is calculated using the corrected lateral acceleration G _YF based on the formula (5). T _OC is this
It is adopted as the calculated value in the step of C8.

When it is determined in step C17 that the turning control flag F _C is not set, the target drive torque T _OC calculated by the equation (8) is not adopted, and the TCL76 sets the target drive torque T _OC. As a result, the maximum torque of the engine 11 is output at C9, and as a result, the ECU 15 reduces the duty ratio of the torque control solenoid valves 51, 56 to the 0% side. As a result, the engine 11 changes the depression amount of the accelerator pedal 31 by the driver. The corresponding drive torque is generated.

If it is determined that the target drive torque T _OC is not equal to or less than the threshold value (T _d -2) in the step C3, the process does not shift to the swing control and shifts from the step C6 or C7 to the step C9.
The TCL76 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, 56 to the 0% side, and as a result, the engine 11 causes the accelerator pedal 31 by the driver to decrease. The drive torque is generated according to the amount of depression of.

Similarly, in the step of C4, even when it is determined that the idle switch 68 is in the ON state, that is, the accelerator pedal 31 is not depressed by the driver, the TCL76 outputs the maximum torque of the engine 11 as the target drive torque T _OC. , By which E
CU15 sets the duty ratio of torque control solenoid valves 51, 56 to 0%
As a result of lowering to the side, the engine 11 generates a drive torque according to the amount of depression of the accelerator pedal 31 by the driver and does not shift to the turning control.

When it is determined in step C2 that the turning control flag F _C is set, the target drive torque T _{OC (n)} calculated this time and the target drive torque T calculated last time are calculated in C10.
_It is determined whether or not the difference ΔT from _{OC (n−1)} is larger than a preset allowable increase / decrease amount T _K. The permissible increase / decrease amount T _K is a torque change amount that does not cause the occupant to feel the acceleration / deceleration shock of the vehicle 82. For example, the target longitudinal acceleration G _XO of the vehicle 82 is set at 0.1 / sec.
If you want to reduce to g, use the above equation (7) Becomes

Target drive torque T calculated this time in step C10
_If it is determined that the difference ΔT between _OC and the previously calculated target drive torque T _{OC (n-1)} is not larger than the preset increase / decrease allowable amount T _K , then in C11 the target drive torque T _OC and the above Difference ΔT with the calculated target drive torque T _{OC (n-1)} is negative Allowable increase / decrease amount _TK
Is greater than.

When the difference ΔT between the target driving torque calculated this time T _OC and the target driving torque T _OC previously calculated _(n-1) at C11 of step is determined to be larger than the negative decrease tolerance T _K, the target calculated this time Drive torque T _OC and target drive torque T calculated last time
Absolute value of the difference between the _{OC (n-1) | ΔT} | because less than decrease tolerance T _K, the target drive torque calculated in the C1 of step
Use T _OC as the calculated value in step C8.

Also, the target drive torque T calculated this time in the step C11
_If it is determined that the difference ΔT between _OC and the target drive torque T _{OC (n-1)} calculated last time is not larger than the negative increase / decrease allowable amount T _K , C12
Then, 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, the reduction range for the target drive torque T _{OC (n-1)} calculated last time is regulated by the allowable increase / decrease amount T _K , and the deceleration is accompanied by the reduction of the drive torque of the engine 11. Reduce the shock.

On the other hand, when 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 determined to be increased or decreased tolerance T _K or more, C13
Then, 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 (n)} = T _{OC (n-1)} + T _{K In other} words, when the drive torque increases, the target drive torque T _OC calculated this time is the same as when the drive torque decreases.
When the difference ΔT between the calculated target drive torque T _{OC (n-1)} and the previously calculated target drive torque T _{OC (n-1)} exceeds the allowable increase / decrease amount T _K , the increase width relative to the previously calculated target drive torque T _{OC (n-1) is} increased / decreased. and regulated by the T _K,
That is, the acceleration shock accompanying the increase in the driving torque of the engine 11 is reduced.

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

Here, if the turning control flag F _C is set, the target drive torque T _OC is not larger than the drive torque T _d requested by the driver, and therefore it is determined at C15 whether or not the idle switch 68 is in the ON state. To do.

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. And
If it is determined in step C7 that the turning control flag F _C is set, or if it is determined in step C17 that the turning control flag F _C is set, C1 or C12
Alternatively, the calculated value adopted in the step C13 is selected as the target drive torque _TOC for turning control.

Further, 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.
Resets the turning control flag F _C at C16. Similarly, if it is determined in step C15 that the idle switch 68 is in the on state, the accelerator pedal 31 is not depressed, so the process proceeds to step C16 and the turning control flag F _C is reset. To do.

When the turning control flag F _C is reset at C16, the TCL76 outputs the maximum torque of the engine 11 at C9 as the target drive torque T _OC , which causes the ECU 15 to output the duty of the torque control solenoid valves 51, 56. As a result of reducing the rate to 0%,
The engine 11 generates drive torque according to the amount of depression of the accelerator pedal 31 by the driver.

In order to simplify the above-described turning control procedure, it is of course possible to ignore the driver's requested drive torque T _d , and in this case, the reference drive torque T _d that can be calculated by the equation (7) as the target drive torque. The drive torque T _B should be adopted.
Further, even when the driver's required drive torque T _d is taken into consideration as in the present embodiment, the weighting coefficient α is not set to a fixed value, but the value of the coefficient α is gradually decreased with the passage of time after the start of control. Alternatively, it may be gradually decreased according to the vehicle speed V to gradually increase the adoption ratio of the driving torque T _d requested by the driver. Similarly, the value of the coefficient α is kept constant for a while after the start of the control, and is gradually decreased after a lapse of a predetermined time, or the value of the coefficient α is increased with an increase in the steering shaft turning amount δ _H. In particular, it is possible to drive the vehicle 82 safely in a turning circuit in which the radius of curvature is gradually reduced.

In the above-described embodiment, the target drive torque for the high μ road is calculated, but the target drive torques for turning control corresponding to the high μ road and the low μ road are calculated respectively, and these target drive torques are calculated. The final target drive torque may be selected from the torque. Further, in the arithmetic processing method described above,
To prevent deceleration shock due to variations in the rapid driving torque of the engine 11, while working to regulation of the target driving torque T _OC by decreasing tolerance T _K when calculating the target driving torque T _OC, this regulation It may be performed for 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, in consideration of the traveling safety of the vehicle 82, the target drive torque having a smaller numerical value is preferentially output. However, in general, the target drive torque T _OS for slip control is always smaller than the target drive torque T _OC for swing control, so the final target drive torque T _O should be selected in the order of slip control and swing control. Good.

As shown in FIG. 34 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 turning control in M11, the slip control flag F in M12 is calculated. _If it is determined whether _S is set and this slip control flag F _S is set, the target drive torque T _OS for slip control is set as the final target drive torque T _O in M13. Select and output this to ECU15.

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

Further, if it is determined in step M14 that the turning control flag F _C is not set, the TCL 76 sets the maximum torque of the engine 11 as the final target drive torque T _O in the ECU 15 in M16.
Output to.

While the final target drive torque T _O is selected as described above, the output of the engine 11 cannot be reduced even by the fully closing operation of the throttle valve 20 via the actuator 41. When the vehicle suddenly changes to a frozen road, the TCL 76 sets a retard ratio for the basic retard amount p _B of the ignition timing P set by the ECU 15, and outputs this to the ECU 15.

The basic delay amount p _B is a maximum value of the delay 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. Further, as the retardation ratio, in this embodiment, 0 level that sets the basic retardation amount p _B to 0,
And I level to compress the basic retard amount p _B two-thirds, basic and II level output as the retardation amount p _B, total closing operation of the throttle valve 20 while it outputs the base retardation amount p _B Do
Four levels, III level, are set, and basically, the retardation rate is selected such that the larger the change rate G _s of the slip amount s becomes, the larger the retardation amount becomes.

As shown in FIG. 35 showing the procedure for reading this retardation rate, the TCL76 first resets the ignition timing control flag F _P at P1 and determines whether the slip control flag F _S is set at P2. To judge. When it is determined in step P2 that the slip control flag F _S is set, the ignition timing control flag F _P is set in P3, and it is determined in P4 whether the slip amount s is less than 0 km / h. To do. If it is determined in step P2 that the slip control flag F _S is not set, the process proceeds to step P4.

In the step of P4, if the slip amount s is less than 0 km / h, that is, if it is judged 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. To do. On the contrary, if it is determined in step P4 that the slip amount s is 0 km / h or more, P6
If the slip rate of change G _s is equal to or less than 2.5g, steps in slip amount change rate G _s of the P6 is equal to or less than 2.5g in the late at P7 It is determined whether or not the angular ratio is at the III level.

Also, the slip amount change rate G _s is 2.5 g in the step of P6.
When it is judged that the front wheels 64 and 65 are slipping abruptly, the final target drive torque T _O is 4 kgm at P8.
It is determined whether the final target drive torque T _O
Is less than 4 kgm, that is, when it is determined that the drive torque of the engine 11 needs to be sharply suppressed, the retard ratio is set to the III level in P9, and the process shifts to P7.
On the contrary, when it is determined in step P8 that the final target drive torque T _O is 4 kgm or more, the process directly proceeds to step P7.

If it is determined in the step of P7 that the retard ratio is the III level, it is determined in P10 whether the slip amount change rate G _s exceeds 0 g. Here, the slip amount change rate G _s is
When it is determined that the slip amount s exceeds 0 g, that is, the slip amount s tends to increase, the ignition timing control flag F is set at P11.
Whether or not _P is set is determined, but if it is determined in step P10 that the slip amount change rate G _s is 0 g or less, that is, the slip amount s is in a decreasing tendency, then at P12 It is determined whether or not the slip amount s exceeds 8 km / h.

If it is determined in step P12 that the slip amount s exceeds 8 km / h, the process proceeds to step P11, and conversely, if it is determined that the slip amount s is 8 km / h or less, P13 The retard ratio is switched from the III level to the II level at, and it is determined at P14 whether the slip amount change rate G _s is 0.5 g or less. Similarly, when it is determined in the step P7 that the retardation ratio is not at the III level, this P14
Go to step.

In the step of P14, if it is determined that the slip amount change rate G _s is 0.5 g or less, that is, the change of the slip amount s is not so rapid, whether or not the retard ratio is II level is determined in P15. To determine. Further, when the slip rate of change G _s was determined not to be less than 0.5g at P14 step, P1
At 6, set the retard ratio to the II level and proceed to the step of P15.

If it is determined in step P15 that the retard ratio is at the II level, the slip amount change rate G
_s is determined whether it exceeds 0 g, when the retard rate conversely is determined that it is not the II level determines whether the slip rate of change G _s is less than 0.3g at P17 . In the step of P16, the slip amount change rate G _s does not exceed 0 g,
That is, when it is determined that the slip amount s tends to decrease, it is determined at P18 whether the slip amount s exceeds 8 km / h. If it is determined in step P18 that the slip amount s is equal to or less than 8 km / h,
Switch the retard ratio from II level to I level with
Go to step 7. Further, when it is judged in the step P16 that the slip amount change rate G _s is 0 g or more, that is, the slip amount s tends to increase, and in the step P18, the slip amount s exceeds 8 km / h. That is, when it is determined that the slip amount s is large, the process proceeds to step P11.

If it is determined in step P17 that the slip amount change rate G _s is 0.3 g or less, that is, the slip amount s has almost no tendency to increase, it is determined in step P20 whether or not the retard ratio is at the I level. judge. On the contrary, if it is judged in the step of P17 that the slip amount change rate G _s exceeds 0.3 g, that is, the slip amount s tends to increase at all, the retard ratio is set to the I level in P21. Set to.

If it is determined at P20 that the retard ratio is at the I level, it is determined at P22 whether the slip amount change rate G _s exceeds 0 g, and this is 0 g or less, that is, the slip amount. When it is determined that s tends to decrease, it is determined in P23 whether the slip amount s is less than 5 km / h.
If it is determined in step P23 that the slip amount s is less than 5 km / h, that is, the front wheels 64 and 65 are hardly slipping, the retard ratio is set to 0 level in P24, and this is set in the ECU 15. Output. Also, if it is determined in step P20 that the retard ratio is not at the I level, or if the slip amount change rate G _s exceeds 0 g in step P22, that is, the slip amount s tends to increase. If the slip amount s is 5 km / h or more in step P23, that is, if the slip amount s is relatively large, the process proceeds to step P11.

On the other hand, in the step of P11, the ignition timing control flag F
_If it is determined that _P is set, it is determined at P25 whether or not the final target drive torque T _O is less than 10 kgm.
When it is determined in step P11 that the ignition timing control flag F _P is not set, the retard ratio is set to 0 level in P26, and then the process proceeds to step P25.

Then, in P25, if it is determined that the final target drive torque T _O is 10 kgm or more, that is, if the engine 11 is generating a slightly larger drive force, the retard ratio is II level in P27. If it is determined that this retardation rate is at the II level, the retardation rate is reduced to the I level at P28, and this is output to the ECU 15.

In the step of P25, the final target drive torque T _O is 10kgm
If it is determined that it is less than the predetermined value, or if it is determined in step P27 that the retard ratio is not at the II level, it is determined in step P29 whether the hydraulic automatic transmission 13 is shifting. Then, if it is determined that the hydraulic automatic transmission 13 is in the process of shifting, it is determined in P30 whether or not the retard ratio is the III level, and in this P30 step, the retard ratio is the III level. If it is determined that the delay ratio is II level in P31, it is output to the ECU15. If it is determined in step P29 that the hydraulic automatic transmission 13 is not shifting,
Alternatively, if it is determined in step P30 that the retard ratio is not at the III level, the retard ratio previously set in P32 is directly output to the ECU 15.

For example, if the retarding proportion of III level is set at P9 step, the slip amount s is greater than the hourly 8km with the slip rate of change G _s is over 0 g, i.e., rate of increase in slip amount s Is sharp, and the final target drive torque T _O
Is less than 10 kgm and the front wheel 6
When it is determined that it is difficult to sufficiently suppress the slip of 4,65, the retard level of the III level is selected and the opening of the throttle valve 20 is forcibly closed to prevent the occurrence of slip. We are trying to efficiently control it in the initial stage.

The ECU15 is retard amount as a preset ignition timing P and basic based on the intake air amount of the engine speed N _E and the engine 11
The ignition timing P and the basic retardation amount p _B are read out from a map (not shown) regarding p _{B based} on the detection signal from the crank angle sensor 62 and the detection signal from the air flow sensor 70, and the timing is sent from the TCL 76. The target retardation amount p _O is calculated by making a correction based on the ratio. 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 purifying 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.

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

As shown in FIG. 36 which represents the operation procedure of the target retard amount p _O in the retarded angle control, firstly ECU15 determines whether the slip control flag F _S described above in Q1 is set, this When the slip control flag F _S is determined to be set, it is determined whether the retard rate at Q2 is set to III level.

Then, when it is determined that the retard ratio is the III level in the step of Q2, 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. Furthermore, the duty ratio of the torque control solenoid valves 51, 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 , and the throttle valve is forcibly throttled. Valve 20
Realize the fully closed state of.

When it is determined in step Q2 that the retard ratio is not at the III level, it is determined at Q5 whether the retard ratio is set at the II level. And when it is judged that the retard ratio is II level in the step of this Q5,
Using base retardation amount p _B read the target retard amount p _O map in step as well as Q6 of the Q3 as it target retard amount p _O, the ignition timing P target retard amount p _O only Delay.
Further, in Q7, the ECU 15 sets the duty ratio of the torque control solenoid valves 51, 56 in Q7 according to the value of the target drive torque T _OS , regardless of the amount of depression of the accelerator pedal 31 by the driver. 11 Drive torque is reduced.

Here, the ECU 15 stores a map for obtaining the throttle opening θ _T using the engine speed N _E and the driving torque of the engine 11 as parameters, and the ECU 15 uses this map to store the current engine speed N _E. And the target throttle opening θ _TO corresponding to this target drive torque T _OS .

Next, the ECU 15 obtains a deviation between the target throttle opening θ _TO and the actual throttle opening θ _T output from the throttle opening sensor 67, and calculates a pair of torque control solenoid valves 51, 56.
Is set to a value commensurate with the deviation, and a current is passed through the solenoids of the plungers 52, 57 of the torque control solenoid valves 51, 56, and the actuator 41 is actuated to change the actual throttle opening θ _T to the target throttle opening. It is controlled so that the temperature decreases to θ _TO .

When the maximum torque of the engine 11 is output to the ECU 15 as the target drive torque T _OS , the ECU 15 is a torque control solenoid valve.
The duty ratio of 51, 56 is reduced to 0%, and the engine 11 is caused to generate a drive torque corresponding to the amount of depression of the accelerator pedal 31 by the driver.

When it is determined in the step Q5 that the retard ratio is not at the II level, it is determined at Q8 whether the retard ratio is set at the I level. If it is judged in the step of Q8 that the retard ratio is set to I level,
The target retardation amount p _O is set according to the following equation, the ignition timing P is retarded by the target retardation amount p _{O, and the} process proceeds to step Q7.

On the other hand, when it is judged in the step of 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, and it is judged that it is 0. In this case, the process proceeds to step Q7, where the ignition timing P is not retarded, and the torque control solenoid valves 51, 56 are set according to the value of the target drive torque T _OS.
Set the duty ratio of the accelerator pedal by the driver
The drive torque of the engine 11 is reduced regardless of the depression amount of 31.

When it is determined in step Q10 that the target retardation amount p _O is not 0, the target retardation amount P _o is set to, for example, 1 by the lamp control at each sampling period Δt of the main timer in Q11.
After subtracting each time until p _O = 0, the shock due to the fluctuation of the driving torque of the engine 11 is reduced, and then the process shifts to the step of Q7.

Note that the slip control flag F _S
Is determined to have been reset, the normal driving control without reducing the driving torque of the engine 11 is performed, the ignition timing P is not retarded by setting p _O = 0 in Q12, and the torque control electromagnetic control is performed in Q13. By setting the duty ratios of the valves 51 and 56 to 0%, the engine 11 generates a driving torque according to the amount of depression of the accelerator pedal 31 by the driver.

<Effects of the Invention> According to the output control device of the present invention, when calculating the correction torque based on the proportion necessary for setting the target drive torque from the reference drive torque, the deviation between the actual drive wheel speed and the target drive wheel speed is calculated. Is smaller than the negative lower limit value, the lower limit value is set as the deviation, and when the deviation is equal to or larger than the lower limit value, the deviation is used as it is, so that the slip of the drive ring converges and the actual drive wheel speed and the target value are set. The deviation from the drive ring speed is a negative value,
When the target drive torque increases due to the correction torque, the value of the deviation does not become smaller than the negative lower limit value due to the limitation by the lower limit value, so that the target drive torque does not increase excessively and is stable. On the other hand, while the control can be realized, when the drive wheels are slipping, the deviation becomes a positive value and is not limited by the lower limit value, so that the correction torque proportional to the deviation is By directly subtracting from the reference drive torque, the target drive torque can be quickly reduced and the slip can be converged.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of one embodiment in which a vehicle output control device according to the present invention is applied to a front-wheel drive type vehicle incorporating a hydraulic automatic transmission of four forward steps and one reverse step, and FIG. FIG. 3, FIG. 3 is a sectional view showing the drive mechanism of the throttle valve, FIG. 4 is a flowchart showing the overall flow of the control, FIG. 5 is a flowchart showing the flow of neutral position learning correction of the steering shaft, and FIG. FIG. 7 is a map showing the relationship between the vehicle speed and the variable threshold value. FIG. 7 is a graph showing an example of a correction amount when the neutral position of the steering shaft is learned and corrected. FIG. 8 is a calculation procedure of a target drive torque for slip control. FIG. 9 is a map showing the relationship between the vehicle speed and the correction coefficient, FIG. 10 is a map showing the relationship between the vehicle speed and the running resistance, and FIG. 11 is a map showing the relationship between the steering shaft turning amount and the correction torque. Figure 12 shows the map immediately after the start of slip control. The map that regulates the lower limit value of the target drive torque, Fig. 13 is a graph showing the relationship between the friction coefficient between the tire and the road surface and the slip ratio of this tire, and Fig. 14 is the target lateral acceleration and speed correction accompanying acceleration. 15 is a map showing the relationship between the lateral acceleration and the speed correction amount associated with turning, FIG. 16 is a circuit diagram for detecting an abnormality of the steering angle sensor, and FIG. 17 is a steering wheel. 18 is a flowchart showing the flow of the abnormality detection processing of the angle sensor 84, FIG. 18 is a map showing the relationship between the vehicle speed and the correction coefficient, FIG. 19 is a flowchart showing the flow of the lateral acceleration selection procedure, and FIG. A map showing the relationship with the proportional coefficient, FIG. 21 is a map showing the relationship between the vehicle speed and the lower limit value of the integral correction torque, FIG. 22 is a graph showing the increase / decrease area of the integral correction torque, and FIG. 23 is the hydraulic automatic gear shift. Compensation corresponding to each gear of the machine and each correction torque A map showing the relationship with the coefficient, FIG. 24 is a map showing the relationship between the engine speed, the required drive torque and the accelerator opening, FIG. 25 is a flowchart showing the flow of slip control, and FIG. 26 is for turning control. FIG. 27 is a block diagram showing the procedure for calculating the target drive torque, FIG. 27 is a map showing the relationship between the vehicle speed and the correction coefficient, and FIG.
FIG. 28 is a graph showing the relationship between the lateral acceleration and the steering angle ratio for explaining the stability factor, FIG. 29 is a map showing the relationship between the target lateral acceleration, the target longitudinal acceleration and the vehicle speed, and FIG.
FIG. 31 is a map showing the relationship between lateral acceleration and road load torque, FIG. 31 is a graph showing an example of a learning correction procedure of the fully closed position of the accelerator opening sensor, and FIG. 32 is a fully closed position of the accelerator opening sensor. Is a flowchart showing another example of the flow of the learning correction, FIG. 33 is a flowchart showing a flow of the turning control, FIG. 34 is a flowchart showing a flow of a selection operation of the final target torque, and FIG. 35 is a selection of the retardation ratio FIG. 36 is a flowchart showing a flow of operation, and FIG. 36 is a flowchart showing a procedure of engine output control. In the figure, reference numeral 11 is an engine, 13 is a hydraulic automatic transmission, and 15
Is an ECU, 16 is a hydraulic control device, 20 is a throttle valve, 23 is an accelerator lever, 24 is a throttle lever, 31 is an accelerator pedal, 32 is a cable, 34 is a claw, 35 is a stopper, 41 is an actuator, and 43 is a control rod. , 47 is a connecting pipe, 48 is a vacuum tank, 49 is a check valve, 50, 55 are pipes, 51, 56 are solenoid valves for torque control, 60 is a solenoid valve, 61 is a spark plug, 62 is a crank angle sensor, 64 , 65 front wheel, 66 front wheel rotation sensor, 6
7 is a throttle opening sensor, 68 is an idle switch, 70
Is an air flow sensor, 71 is a water temperature sensor, 74 is an exhaust temperature sensor, 75 is an ignition key switch, 76 is TCL, 77 is an accelerator opening sensor, 78 and 79 are rear wheels, 80 and 81 are rear wheel rotation sensors, and 82 is Vehicle, 83 is a steering axis, 84 is a steering angle sensor, 85 is a steering wheel, 86 is a steering axis reference position sensor, 87 is a communication cable, 104, 105, 117, 135 are multiplying sections, 106, 131 are differential calculating sections, 107, 110, 125 are clip sections, 108, 123 are filters. Department,
109 is a torque conversion unit, 111 is a running resistance calculation unit, 112, 114, 11
9 is an addition unit, 113 is a cornering drag correction amount calculation unit,
115 is a variable clip unit 116, 121, 124 is a subtraction unit, 118 is an acceleration correction unit, 120 is a turning correction unit, 122 is a lateral acceleration calculation unit, A is a stability factor, b is a tread, F _P is an ignition timing control flag, F _S is the slip control flag, G _F is the actual front wheel acceleration, G _KC and G _KF are the front wheel acceleration correction amount, G _s is the slip change rate, G _XF is the corrected longitudinal acceleration, G _XO is the target longitudinal acceleration, and G _YO Is the target lateral acceleration, g is the gravity acceleration, N _E is the engine speed, P is the ignition timing, p _B is the basic retardation amount, p _O is the target retardation amount, r is the wheel effective radius, S _O is the slip ratio, s is the slip amount, T _B is the reference drive torque, T _C is the cornering drag correction torque, T _D is the differential correction torque, T _d is the required drive torque,
T _I is the integral correction torque, T _O is the final target drive torque, T _OC is the target drive torque for turning control, T _OS is the target drive torque for slip control, T _P is the proportional correction torque, T _PID is the final correction torque, T _R is running resistance, Δt is sampling period, V is vehicle speed, V _F is actual front wheel speed, V _FO and V _FS are target front wheel speeds, V _K and V _KC are slip correction amounts, and V _RL is left rear wheel speed, V _RR is the right rear wheel speed, V _S is the vehicle speed for slip control, W _b is the vehicle body weight, δ is the steering angle of the front wheels,
δ _H is the turning angle of the steering shaft, ρ _d is the operating gear reduction ratio, ρ _KI is the integral correction coefficient, ρ _KP is the proportional correction coefficient, ρ _m is the gear ratio of the hydraulic automatic transmission, and ρ _T is the torque converter ratio. is there.

Claims (1)

(57) [Claims] 1. A torque reducing means capable of reducing a drive torque of an engine independently of an operation by a driver, and a reference drive torque as a reference value of a drive torque when the vehicle is driven by the engine, a vehicle body acceleration of the vehicle. Based on the reference drive torque setting means, target drive wheel speed setting means for setting the target peripheral speed of the drive wheels, drive wheel speed detecting means for detecting the actual drive wheel speed, actual drive wheel speed and target drive When the deviation from the wheel speed is smaller than the negative lower limit value, the lower limit value is output as the deviation, and when the deviation is equal to or larger than the lower limit value, the clipping means outputs the deviation as it is, and the clipping means outputs the deviation. Proportional correction torque calculating means for calculating a correction torque proportional to the calculated deviation, and setting the target drive torque of the engine by subtracting this correction torque from the set reference drive torque. Target drive torque setting means for controlling the output of the vehicle, and a torque control unit for controlling the operation of the torque reducing means so that the drive torque of the engine approaches the set target drive torque. apparatus.