JPH0777852B2 - Driving force control device for vehicles with automatic transmission - Google Patents

Description

TECHNICAL FIELD The present invention relates to a driving force control device for a vehicle including an automatic transmission with an electronic control device.

[Conventional technology]

As a conventional vehicle driving force control device, for example, Japanese Patent Laid-Open No.
There is one such as that described in Japanese Patent Laid-Open No. 43133.

In an engine output control device for an automobile, which controls the engine output by changing the amount of fuel supplied to the engine in accordance with the accelerator pedal position, it is a driving wheel rotational speed detecting means, a non-driving wheel rotational speed detecting means, both detecting means. Calculating means for calculating the tire-road surface slip ratio from the output, comparing means for comparing the calculated slip ratio and the set slip ratio, and giving priority to the control output based on the accelerator pedal position when the calculated slip ratio is large. And a slip ratio control means for outputting a signal for forcibly reducing the fuel supply to the engine.
By determining the slip ratio between road surfaces and controlling the engine so that the slip ratio is below a certain value, the starting performance and running stability on the road surface with a low friction coefficient are improved.

[Problems to be solved by the invention]

However, in such a conventional vehicle driving force control device, regardless of whether the transmission is an automatic transmission or a manual transmission, it is calculated from the driving wheel rotation speed and the non-driving wheel rotation speed. It is configured to control the driving force by the driving force control device based on the slip ratio between the tire and the road surface, and since there is no means for controlling the state of the automatic transmission even in a vehicle with an automatic transmission, A vehicle with an automatic transmission has a problem that appropriate drive force control cannot be performed.

That is, in a vehicle equipped with an automatic transmission having a lock-up mechanism, the lock-up operation and its release are set based on the throttle opening, shift position, vehicle speed, etc. When the driving force of the engine is reduced, the lockup state is determined by the opening of the throttle valve, so the lockup is released when the throttle is fully closed, etc., and a large braking force is transmitted to the drive wheels. Therefore, the driving force cannot be efficiently reduced. Further, in a normal automatic transmission, the shift position is determined by the throttle valve opening and the vehicle speed. Therefore, when the throttle valve is fully closed, the shift position is held at the highest position or the shift up control is performed. Therefore, the engine speed decreases, the braking force decreases, and the responsiveness of the driving force deteriorates.
In addition, the line pressure of the hydraulic control device of the automatic transmission is cut back when the vehicle speed is equal to or higher than a set value, and the cut back is released when the vehicle speed is less than the set value. Since the clutch pressure is low, the clutch capacity is insufficient and the braking force of the engine cannot be efficiently transmitted to the drive wheels.

[Means for solving problems]

The present invention has been made in view of such conventional problems, and as shown in the basic configuration diagram of FIG. 1, an automatic transmission capable of automatically changing a transmission gear ratio, and Slip detection means for detecting the slip state of the drive wheels driven via the automatic transmission and outputting the slip detection signal, and the drive force of the engine according to the slip state of the drive wheels based on the slip detection signal. Variable drive force control means, and a control signal for controlling the drive force transmitted from the engine to the drive wheels of the automatic transmission so as to be retained or increased during the drive force reduction control of the engine. The above problem is solved by configuring a driving force control device for a vehicle with an automatic transmission, including a control device output means for outputting

[Action]

Thus, in the present invention, the slip state of the drive wheels is detected by the slip detection means, the drive force control means controls the drive force of the engine in accordance with the slip state, and the drive force control means is activated by the slip detection. Then, when the driving force of the engine decreases, the control signal output means outputs a control signal so that the driving force transmitted from the engine to the driving wheels of the automatic transmission is maintained based on the control signal, or By controlling in the increasing direction (for example, lockup control, overdrive control, shift control, line pressure control, etc.), the braking force (negative driving force) by the engine can be efficiently obtained even in a vehicle with an automatic transmission. Thus, the slip of the vehicle is suppressed early and the driving performance at the time of slip is improved.

〔Example〕

 Hereinafter, the present invention will be described based on illustrated embodiments.

FIGS. 2 to 5 show an embodiment of the present invention and are applied to a rear-wheel drive vehicle having an automatic transmission.

First, the configuration will be described. 1 shown in FIG. 2 is an accelerator potentiometer, which is configured to interlock with the depression of the accelerator pedal 2 and has a voltage corresponding to the depression amount (stroke amount) of the accelerator pedal 2. The accelerator signal DA is output to the control device 3.

The control device 3 includes a microcomputer 4, an A / D converter 5, an F / V converter 6, and a motor drive circuit 7, and the F / V converter 6 is the A / D converter 5 The A / D converter 5 and the motor drive circuit 7 are connected to the microcomputer 4. Microcomputer 4
Is an interface circuit 4a and an arithmetic processing unit (CPU) 4b
And a storage device 4c such as RAM or ROM, and the accelerator signal DA and a rotation speed signal DV from the F / V converter 6 to be described later are
It is supplied to the arithmetic processing unit 4b via the / D converter 5 and the interface circuit 4a, and the arithmetic processing unit 4b is stored in the storage unit 4c.
Is operated according to a program stored in advance.

In the storage device 4c, the steps shown in FIG. 3, and the graphs shown in the steps are stored in the storage areas corresponding to them in the form of storage tables.

The storage table corresponding to the graph shown in the step is the change amount reference value-motor speed conversion table 4d for converting the change amount reference value ΔS ₀ of the slip ratio S shown on the horizontal axis into the motor speed shown on the vertical axis. . The storage table corresponding to the graph shown in the step is the stroke amount-target opening degree conversion table 4e, and the accelerator pedal 2 shown on the horizontal axis.
Is converted into the target opening degree θ ₀ of the throttle valve 18 shown on the vertical axis. The storage table corresponding to the graph shown in the step is the deviation-motor speed conversion table 4f, which converts the deviation Dif of the throttle valve opening on the horizontal axis into the motor speed on the vertical axis.

Further, the storage device 4c stores a reference slip ratio storage area 4g in which a preset set value (reference slip ratio S ₀ ) serving as a slip ratio determination reference is stored, and a logical value for determining the opening / closing speed of the throttle valve 17. A determined speed storage area 4h in which a speed determination flag of "1" or "0" is stored, a target opening storage area 4i in which a target opening θ ₀ of the throttle valve 17 is stored, a normal rotation of the step motor 16, A motor rotation direction storage area 4j that stores a designated value that designates reverse rotation or holding, a start cycle storage area 4k that stores an activation cycle of an OCI interrupt described later, and a change amount reference value ΔS _{0 of} the slip ratio S are stored. Change amount reference value storage area 4m and the actual opening of the throttle valve 17 (actual opening)
And an up / down counter 4n that stores a value corresponding to, an OCI interrupt is executed based on the cycle time stored in the startup cycle storage area 4k.

Furthermore, in the storage device 4c, a drive wheel control state storage area 4p in which a drive force control flag having a logical value "1" or "0" indicating whether or not the mobility reduction control is being performed is stored, and a drive force. The timer 4q stores a time value T representing the elapsed time after the reduction control is released by the number of subsequent interrupt processes.

The up / down counter 4n is a step motor.
16 is capable of counting up by a number corresponding to the number of steps required to drive the throttle valve 17 from the fully closed state to the fully open state.
It is set to 0 when 17 is fully closed.

Further, the F / V converter 6 includes the left and right rear wheels which are driving wheels.
The drive wheel rotation speed signal DVr from the rear wheel rotation speed detector 10, which is the drive wheel rotation speed detecting means for detecting the rotation speeds of 8, 9 and the rotation speeds of the left and right front wheels 11, 12 which are non-driving wheels are individually Right non-driving wheel rotation speed signal from the right front wheel rotation speed detector 13 and the left front wheel rotation speed detector 14 which are non-driving wheel rotation speed detecting means for detecting
The DVfr and the left non-driving wheel rotation speed signal DVfl are respectively supplied.

Here, the rear wheel rotation speed detector 10 detects the rotation speed of the drive wheel by detecting the rotation speed of the differential gear 15 that transmits the driving force to the left and right rear wheels 8 and 9, and responds to the rotation speed. The drive wheel rotation speed signal DVr, which is a pulse signal of a frequency, is output to the F / V converter 6. Further, the left and right front wheel rotation speed detectors 13 and 14 directly detect the rotation speeds of the left and right front wheels 11 and 12, respectively, and the left and right non-driving wheel rotation speed signals which are pulse signals having a frequency corresponding to the rotation speed. Similarly, DVfr and DVfl are output to the F / V converter 6, respectively.

The F / V converter 6 converts the driving wheel rotation speed signal DVr and the left and right non-driving wheel rotation speed signals DVfr, DVf1 into voltages corresponding to the respective frequencies, and these rotation speed signals DV are converted into A / D converters 5. It is converted into a digital signal by and is supplied to the microcomputer 4. As a result, the arithmetic processing unit 4b of the microcomputer 4 receives the three input rotational speed detectors 10, 13, 14
A control process described later is executed based on the rotation speed signal DV from the accelerator potentiometer 1 and the accelerator signal DA from the accelerator potentiometer 1, and the motor control signal CS ₁ is sent to the motor drive circuit based on the calculated slip ratio S and the variation ΔS thereof. 7 and outputs the A / T control signal CS ₂ to the transmission control circuit 20 based on the slip ratio S.

The motor drive circuit 7 operates the step motor 16 based on the motor control signal CS ₁ output from the microcomputer 4.
The driving current is output to the step motor 16 to rotate the step motor 16 in the normal direction or the reverse direction, or the non-rotation state is maintained. The rotary shaft 16a of the step motor 16 is formed integrally with the rotary shaft of the throttle valve 17, and the forward rotation of the step motor 16 opens the throttle valve 17 and the reverse rotation thereof closes the throttle valve 17, for example.

Further, the transmission control circuit 20 controls the operating state of the automatic transmission 21 based on the A / T control signal CS ₂ output from the microcomputer 4. Examples of the automatic transmission 21 include the automatic transmission with a 4-speed lockup mechanism described in Nissan OD automatic transmission maintenance manual L4N71B type, E4N71B type (November 1982: Nissan Motor Co., Ltd.). A known structure can be adopted.

The automatic transmission 21 is composed of a torque converter, a transmission, and a hydraulic control device thereof, and is roughly classified into four types of mechanisms, that is, a normal transmission mechanism, an overdrive mechanism (OD mechanism), and a lockup mechanism. And a cutback mechanism.

A normal speed change mechanism is a mechanism that automatically selects an optimum shift position by shifting up or down according to a control condition such as a vehicle speed within a range from the first speed to the third speed. It is equipped with a downshift control function that shifts down from the third speed to the second speed during braking under the conditions and holds the second speed until re-acceleration.

Further, the OD mechanism is a mechanism capable of shifting from the third speed to the fourth speed, and the lockup mechanism is a mechanism capable of directly connecting the torque converter. Among them, the downshift control includes a shift switch for detecting the shift position, an idle switch for detecting the throttle opening, and a brake switch for detecting the operation of the brake, as described on page 12 of the maintenance manual. , And four types of vehicle speed sensors for detecting the vehicle speed and a downshift solenoid are used, and when a predetermined condition is satisfied, a downshift signal is output from the control device 3, whereby the downshift solenoid is turned on to shift. Down control is performed. In this case, it is possible to improve the engine braking effect and the fuel consumption when going down a slope.

Further, the OD control enables the shift control between the third speed and the fourth speed by turning on and off the OD solenoid according to the traveling state such as the throttle opening and the vehicle speed. For this OD control, as described on page 20 of the same maintenance manual, there are five types of sensors: a shift switch, a high throttle switch and a kick down switch for judging the throttle range, a low temperature switch and a vehicle speed sensor. , An overdrive (OD) solenoid is used, and the OD control signal is output from the control device 3 when the control conditions are satisfied.
The solenoid turns on and OD control is released.

Further, the lock-up control is to increase the transmission efficiency by directly connecting the torque converter to eliminate slippage, and is performed by controlling the converter pressure acting on the lock-up piston in the torque converter with the lock-up control valve. This lockup control includes shift switch, high throttle switch for determining throttle range, kick down switch, idle switch, low temperature switch, and vehicle speed sensor, as described on page 16 of the maintenance manual. 7 types of sensors and a lock-up solenoid are used, and a lock-up signal is output from the control device 3 according to the lock-up vehicle speed, whereby the lock-up solenoid is turned on and off to perform lock-up control.

Further, as the above-mentioned cutback mechanism, there is one having a structure as described in Japanese Patent Application No. 54-99123 (Japanese Patent Laid-Open No. 56-24255) filed previously by the applicant. Itself is
It consists of a cutback solenoid and a cutback control circuit that controls the energization of this solenoid to change the line pressure. At the time of cutback, the cutback solenoid is energized to close the nozzle, and the hydraulic pressure control valve The line pressure of the liquid path adjusted by is decreased. On the contrary, by keeping the cutback solenoid in the non-energized state and opening the nozzle, the line pressure of the liquid passage adjusted by the liquid pressure control valve can be increased.

This cutback control adjusts the line pressure by the action of governor pressure, and the clutch engagement pressure during running may be smaller than when starting, and if the line pressure is kept high during starting, The shift shock becomes large,
This is done to prevent the pump loss as it also increases.

Further, the arithmetic processing unit 4b of the microcomputer 4
Performs arithmetic processing according to a timer interrupt processing program stored in the ROM in advance, for example, shown in FIG. 3 and executed every 100 msec, for example, and shown in FIG. 4 for each activation cycle based on the processing result. Executes the overflow counter interrupt interrupt processing (OCI interrupt).

That is, in the step, the drive wheel rotation speed signal DVr of the rear wheel rotation speed detector 10 is read, the rotation speeds of the left and right rear wheels 9 and 10 which are the drive wheels are calculated based on the read signal DVr, and this is calculated as the drive wheel rotation speed.
It is temporarily stored as Vr in a predetermined storage area of the storage device 4c.

Next, shifting to step, the right non-driving wheel rotation speed signal DVfr of the right front wheel rotation speed detector 14 is read, the rotation speed of the right front wheel 12 which is a non-driving wheel is calculated based on this, and this is driven to the right The wheel rotation speed Vfr is temporarily stored in a predetermined storage area of the storage device 4c.

Next, in step S15, the front left wheel rotation speed detector 15
The left non-driving wheel rotational speed signal DVfl is read, the rotational speed of the left front wheel 13 which is a non-driving wheel is calculated based on that, and this is temporarily stored as a left non-driving wheel rotational speed Vf1 in a predetermined storage area of the storage device 4c. .

Then, the process proceeds to step, where the right non-driving wheel speed Vfr of the step and the left non-driving wheel speed Vfl of the step are read out, and based on these left and right non-driving wheel speeds Vfr, Vfl And calculate this as the non-driving wheel speed
It is temporarily stored as Vf in a predetermined storage area of the storage device 4c. This non-driving wheel rotation speed Vf is the left and right front wheels 12, 13 in this embodiment.
The average value of the rotation speed of is used.

Next, the process proceeds to step, the driving wheel rotation speed Vr of the step and the non-driving wheel rotation speed Vf of the step are read out, and the driving wheels are driven based on the respective rotation speeds Vf, Vr of the front wheels and the rear wheels.
The slip ratio S between the tire and the road surface generated between the tires 9 and 10 and the road surface is calculated.

Then, the process proceeds to step, where the slip ratio S new calculated this time and the slip ratio S old calculated by the previous timer interrupt are read, and the previous slip ratio S old is subtracted from the slip ratio S new this time. Change amount of slip ratio S
Calculate S.

Next, the operation shifts to slip, and the reference slip rate S ₀ stored in advance in the reference slip rate storage area 4g of the storage device 4c and the slip rate S calculated in step are read out, and the slip rate S is the reference slip rate S _0. Determine if it is greater. As a result of the determination, when the slip ratio S is larger than the reference slip ratio S ₀ (S> S ₀ ), the control shifts to the driving force reduction control below the step, and when the slip ratio S is the reference slip ratio S ₀ or less. In (S ≦ S ₀ ), the control proceeds to the driving force normal control below the step.

In the driving force reduction control, first, in step, it is determined whether the speed determination flag, which is the content of the determined speed storage area 4h of the storage device 4c, has the logical value "1". The determination in this case is to check whether or not the slip state of the vehicle which is equal to or greater than a predetermined value continues from the time of the previous timer interrupt processing to the time of this processing, and the speed determination flag is the logical value "1". Occasionally, it is judged that the vehicle slip has continued from the previous time, and the process proceeds to step, while the content is a logical value "0".
When it is, it is determined that the previous slip state is below a predetermined value, and the process proceeds to step.

In this step, the logical value "1" is stored in the determined speed storage area 4h.
Is set, and then the process proceeds to step to read the change amount ΔS of the slip ratio S calculated at step,
This change amount ΔS is temporarily stored in the change amount reference value storage area 4m of the storage device 4c as the slip ratio change amount reference value ΔS ₀ .

Then, the process shifts to step, and a command value 0 for designating the target opening θ ₀ of the throttle valve 17 to be fully closed is set in the target opening storage area 4i of the storage device 4c.

Next, the process proceeds to step, the slip ratio change amount reference value ΔS ₀ of the step is read, and the motor speed is searched by referring to the change amount reference value-motor speed conversion table 4d stored in the storage device 4c. To set.

Next, the process proceeds to step, and the current opening θ which is the content of the up / down counter 4n (0 when fully closed) of the storage device 4c.
And the target opening θ ₀ specified in step,
Currently calculated deviation Dif opening theta with respect to the target opening degree theta ₀ by subtracting the current opening theta from target opening theta _0, storage device which 4
It is temporarily stored in a predetermined storage area of c.

In the next step, the deviation Dif calculated in the step
Is read, and based on this, it is determined whether to rotate the step motor 17 forward or backward, or to keep the current state, and a predetermined value representing the determination result is temporarily stored in the motor rotation direction storage area 4j of the storage device 4c. The decision in this case is the deviation Di
It is performed by observing the contents of f. When the deviation Dif is positive, it is forward rotation, when the deviation Dif is negative, it is reverse rotation.
Further, when the deviation Dif is 0, it is determined that the current state is held.

Then, the process proceeds to step, and the activation cycle of the OCI interrupt, which will be described later, is determined based on the motor speed calculated in the step, and the time is stored as the activation cycle storage area of the storage device 4c.
Set to 4k.

This completes the timer interrupt process and returns to the main program, and then shifts to the OCI interrupt process in FIG.

In addition, the normal driving force control is as follows.
By resetting the speed determination flag in the determined speed storage area 4h of the storage device 4c, the content is rewritten to a logical value "0", and then the process proceeds to step to read the accelerator signal DA from the accelerator potentiometer 1 and Based on this, the depression amount of the accelerator pedal 2 is calculated, and this is temporarily stored as a stroke amount L of the pedal in a predetermined storage area of the storage device 4c.

Next, the process proceeds to step, the stroke amount L of the step is read, the stroke amount-target opening degree conversion table 4e stored in the storage device 4c is referred to, and the target opening degree of the throttle valve 18 is calculated from the stroke amount L. θ ₀ is searched and determined.

Then, the process shifts to the step, and the deviation Dif is calculated by subtracting the actual opening θ from the target opening θ ₀ of the throttle valve 18 in the same manner as the above step. Then, the process shifts to step, the motor speed is searched and determined based on the deviation Dif calculated in step by referring to the deviation-motor speed conversion table 4f stored in the storage device 4c. After that, the process shifts to the step.

Next, the OCI interrupt processing of FIG. 4 will be described. This OCI
As described above, the interrupt process is executed with the activation cycle of the time set in the step.

That is, first, in step, it is determined whether or not the rotational position of the step motor 17 is currently held and is not rotated. In this case, the determination is made in the step motor rotation direction storage area
It is executed by looking at the contents of 4j. As a result of the determination, when it is determined that the rotational position of the step motor 17 is maintained as it is, the current OCI interrupt processing is ended, and the OCI
The OCI interrupt process is executed again according to the activation cycle of the interrupt process, or the main program is returned to and the timer interrupt process of FIG. 3 is executed after a predetermined time.

On the other hand, when it is determined in step that the rotational position of the step motor 17 is not currently held, the process proceeds to step and it is determined whether or not the step motor 17 is normally rotated. The determination in this case is also made by looking at the contents of the motor rotation direction storage area 4j at the step, as in the step. As a result of the judgment, the step motor 17
When rotating normally (direction to open the throttle valve 18),
Go to step, add 1 to the current value θ of up / down counter 4n, and then go to step, while rotating step motor 17 in the reverse direction (direction to close throttle valve 18)
When this is done, the process proceeds to step, 1 is subtracted from the current value θ of the up / down counter 4n, and then the process proceeds to step.

In this step, the drive signal CS for rotating the step motor 17 forward by one step, or the step motor 17
The drive signal CS for reversing 17 by one step is output, and this ends the OCI interrupt processing this time.

In addition, the arithmetic processing unit 4b of the control device 3 includes the third and fourth
A / T for controlling the operating state of the automatic transmission 21 according to a timer interrupt processing program stored in the ROM separately from the timer interrupt processing shown in the figure and executed, for example, every 100 msec shown in FIG. The arithmetic processing for outputting the control signal CS ₂ is executed.

In this process, first, in step, the slip ratio S calculated in the step of the driving force control process and the reference slip ratio S ₀ stored in the reference slip ratio storage area 4g of the storage device 4c are read out, and the subsequent step Then, it is determined whether or not the calculated slip ratio S is larger than the reference slip ratio S ₀ . The determination in this case is to check whether the traveling state of the vehicle is under the condition for performing the driving force reduction control, and when the determination result is S> S ₀ , the driving force reduction control is being performed. Judge and proceed to the step.

In this step, the driving force control flag is set in the driving force control state storage area 4p provided in advance in the storage device 4c (logical value "1").

Next, the process proceeds to step, the timer 4q provided in the storage device 4c is cleared to 0, and then the process proceeds to step to check whether or not the content of the driving force control flag is the logical value "1". judge. The determination in this case is to see whether or not the driving force reduction control is being executed. As a result of the determination, when the content of the driving force control flag is the logical value "1", it is determined that the driving force reduction control is being performed, and the process proceeds to step.

In this step, the braking force (negative driving force) transmitted from the engine to the rear wheels 8 and 9 as driving wheels is maintained as it is or is increased from the current value as the operating state of the automatic transmission 21. The lockup operation (control) signal for performing lockup control and the cutback release (control) signal for canceling the line pressure cutback control and maintaining the line pressure , An OD cancellation (control) signal for canceling the overdrive (OD) and a downshift operation (control) signal for downshift control are output to the transmission control circuit 20.

This completes the timer interrupt process and returns to the main program.

On the other hand, as a result of the determination in the step, when the content of the driving force control flag is the logical value “0”, it is determined that the driving force reduction control is not being performed, and the process proceeds to step.

In this step, a lockup release (control) signal for releasing the lockup control as a signal for controlling the operating state of the automatic transmission 21 and a cut for setting the line pressure to the pressure at the time of cutback A back operation (control) signal, an OD operation (control) signal for continuing OD control, and a downshift cancellation (control) signal for canceling downshift are output to the automatic transmission control circuit 20.

Further, in the step, when the verification result is S> S _0, it is determined that the driving force reduction control is not in progress, and the process proceeds to the step.

In this step, similarly to the above step, it is determined whether or not the content of the driving force control flag is the logical value "1". The determination in this case is to determine whether the driving force reduction control is performed from the current timer interrupt process or is continued from the previous process. As a result of the determination, when the content of the driving force control flag is the logical value "1", it is determined that the driving force reduction control is canceled, and the process proceeds to step.

In this step, it is determined whether or not the time value T of the timer 4q is longer than a preset predetermined time T ₀ . The determination in this case is to see whether or not a predetermined time T ₀ or more has elapsed since the driving force reduction control was released. As a result of the determination, when the predetermined time T ₀ has not yet passed (T ≦ T ₀ ).
In step S4, the value T of the timer 4q is incremented by 1 to rewrite the contents of the timer 4q, and then the step S1 is performed. However, when the predetermined time T ₀ has already elapsed (T> T ₀ ), the process proceeds to step, the driving force control flag in the driving force control state storage area 4p is reset to “0”, and the timer 4p After clearing the content of 0 to 0, the process proceeds to the step.

The steps from step to step constitute a slip detection means, the steps from step to step the motor drive circuit 7 and the step motor 16 constitute driving force control means, and the steps from step to step control signal output means. Are configured.

Next, the operation will be described.

Now, assuming that the vehicle is traveling on a road with a low road surface friction coefficient such as a snow road or an ice burn, and the timer interrupt process of FIG. 3 is executed every predetermined time in this state, first,
The driving wheel speed Vr is read in step, the right non-driving wheel speed Vfr is read in the next step, the left non-driving wheel speed Vfl is further read in step, and the left and right non-driving wheel speeds are read in the next step. Calculate Vfr, Vfl or the non-driving wheel speed Vf of the entire non-driving wheels.

In the next step, the slip ratio S between the tire and the road surface, which represents the slip state of the vehicle with respect to the road surface, is calculated based on the drive wheel speed Vr and the non-drive wheel speed Vf, and in the next step, this time. Of the slip ratio Snew is subtracted from the previous slip ratio Sold to calculate the change amount ΔS of the slip ratio S, and in the next step, it is determined whether or not the slip ratio S is larger than the reference slip ratio S _0. .

At this time, even if the vehicle is not in the slip state or is in the slip state, the slip rate S is the reference slip rate S _0.
If it is below, the process proceeds to the driving force normal control below the step according to the determination of the step, first, the speed determination flag 4h is reset to "0" in the step, and then the stroke amount L of the accelerator pedal 2 in the step. Read
In the next step, from the stroke amount L to the target opening θ ₀
In the subsequent stroke, the deviation Dif is calculated from the target opening θ ₀ and the current opening θ, and in the next step,
Determine the motor speed from the deviation Dif.

Then, in the next OCI interrupt, the step motor 16 determines the sign of the deviation Dif expressed as the difference between the target opening θ ₀ and the actual opening θ based on the motor speed determined as described above, and its sign. The throttle valve 17 is rotationally driven by the rotation direction and the rotation amount corresponding to the value, whereby the throttle valve 17 rotates integrally with the step motor 16, and the opening thereof is controlled according to the depression amount of the accelerator pedal 2.

When the timer interrupt process of FIG. 5 is executed under such a running state, the target opening θ ₀ and the actual opening θ of the throttle valve 17 in step S are read, and the determination in the next step is executed. Then, since the traveling state of the vehicle is not under the condition that the driving force reduction control needs to be performed, it is determined that S ≦ S ₀ as in the above step. Therefore, it is determined whether or not the driving force control flag of the driving force control state storage area 4p of the storage device 4c is "1" in step S4. Since it is reset to "0", the process moves to the next step and the timer 4q of the storage device 4c is cleared to "0".

Then, in the next step, it is determined whether or not the driving force control flag is "1". However, since the driving force control flag is "0", the process proceeds to the next step, and the lock for releasing the lockup is released. Up release signal, cutback operation signal that lowers the line pressure from the state before cutback, and OD
An OD operation signal for continuing the control and a downshift cancel signal for canceling the downshift control are output to the transmission control circuit 20.

As a result, the transmission control circuit 20 outputs to the automatic transmission 21 four types of drive signals for controlling four types of operating states of the automatic transmission 21.

Explaining this with reference to the above-mentioned reference, the control of the first operating state is to release the lockup by the lockup control signal, and by turning off the lockup solenoid by the lockup release signal, the lockup control valve is released. Is held inactive, and the lockup piston does not operate, so the torque converter is in a non-direct connection state.

The control of the second operating state is the reduction of the line pressure by the cutback control signal, and by turning on the cutback solenoid by the cutback operation signal, the line pressure becomes low through the action of the hydraulic pressure regulating valve.

The third operating state control is the OD control by the OD control signal, and by turning on the OD solenoid by the OD release signal, the OD control is performed.
It enables shifting to the 4th speed through the operation of the control valve.

Further, the control of the fourth operating state is shift control by the downshift control signal, and by turning off the 1-2 shift solenoid or the 2-3 shift solenoid, the shift up control can be performed according to the vehicle speed.

On the other hand, the vehicle is in a slip state and its slip ratio S
Is larger than the reference slip ratio S ₀ , the process proceeds to the driving force reduction control below the step by the determination of the step in FIG. 3 and whether the content of the speed determination flag 4h is “1” is first determined in the step. To judge. At this time, when the speed determination flag 4h is reset to "0" because the vehicle is not in the slip state in the previous timer interrupt processing, the speed determination flag 4h is set to "1" in the step Then, the contents of the change amount reference value storage area 4m are rewritten with the slip ratio change amount ΔS calculated in step, and then the process proceeds to step, while the speed determination flag 4h is set to "1", the step is directly performed. Move to.

In this step, regardless of the current stroke amount L of the accelerator pedal 2, a specified value 0 for designating the target opening θ ₀ to be fully closed (0) is stored in the target opening storage area 4i, and in the next step, The motor speed of the step motor 16 is determined based on the variation reference value ΔS ₀ .

In the subsequent step, the deviation Dif is calculated from the target opening θ ₀ and the current opening θ, but the opening of the throttle valve 17 is opened according to the depression amount of the accelerator pedal 2, while the target opening θ ₀ Is 0, the deviation Dif has a negative value. Therefore, in the next step, the rotation direction of the step motor 16 is determined to be the reverse rotation direction, and in the next step, a relatively short start cycle corresponding to the motor speed is set.

As a result, when the OCI interrupt of FIG. 4 is executed following this timer interrupt process, first, in step, the step motor
It is determined that 16 is not held at the current position, and it is determined that the step motor 16 will be rotated in the next step.
In the next step, 1 is subtracted from the current opening θ, and in the next step, the motor control signal CS ₁ for rotating step 16 in the reverse direction by one step is sent to the motor drive circuit 7
Is output to. As a result, the motor drive circuit 7 outputs a motor drive signal to the step motor 16, so that the step motor 16 rotates one step, and the throttle valve 17 is closed by the rotation angle.

Next, assuming that the next OCI interrupt is started by the activation cycle set in step, in the same manner as described above, 1 is subtracted from the current opening θ in step and through step, and in the next step, A motor drive signal for rotating the step motor 16 in the reverse direction by one step is sent via the motor drive circuit 7 to the step motor.
Output to 16. As a result, the step motor 16 rotates one step, the throttle valve 17 is further closed by the rotation angle, and this OCI interrupt continues until the predetermined time required for one cycle of the timer interrupt processing in FIG. 3 has elapsed. In this way, the driving force of the engine is reduced relatively early.

When the timer interrupt process of FIG. 5 is executed subsequent to such driving force reduction control, it is determined in step S> S ₀ , that is, the driving force reduction control is being executed, so Set the driving force control flag to "1",
After the timer 4q is cleared to 0 in the next step, it is determined in the next step whether or not the driving force control flag is "1".

In this case, the driving force control flag is set to "1" depending on the step.
Is set to, so move to the next step,
A lockup operation signal that locks up the torque converter in a direct connection state, a cutback release signal that increases the line pressure even at a certain vehicle speed, an OD release signal that releases OD control, and a downshift operation signal that performs downshift control. And are output to the transmission control circuit 20.

That is, the control of the first operating state is the lockup operation by the lockup control signal, and the lockup control valve is switched to the operating state by turning on the lockup solenoid by the lockup operation signal, whereby the lockup The piston operates and the torque converter is directly connected.

The control of the second operation state is to increase the line pressure by the cutback control signal, and by turning on the cutback solenoid by the cutback operation signal, the line pressure is lowered via the action of the hydraulic pressure regulating valve.

The control of the third operating state is the release of the OD control by the OD control signal, and by turning off the OD solenoid by the OD release signal, the shift up to the fourth speed is prevented through the operation of the OD control valve.

Further, the fourth operating state is shift control by the downshift control signal, and by turning off the downshift solenoid, the vehicle is downshifted to the second speed at the same time as braking under the control condition, and then the second shift is performed until re-acceleration. Holds speed and prevents upshifting to 3rd speed.

As a result, the output shaft of the engine and the drive shaft on the drive wheel side are rigidly connected via the torque converter in the direct connection state, so that the braking force (negative drive force) is efficiently transmitted from the engine to the drive wheel. Thus, even in a vehicle equipped with an automatic transmission, the braking force generated by reducing the driving force of the engine can be effectively transmitted to the driving wheels. Therefore, the slip of the drive wheels can be suppressed at an early stage, the slip state of the vehicle can be avoided early, and traveling stability can be ensured.

The operation state control of the automatic transmission 21 is continued until the slip ratio S falls below the reference slip ratio S ₀ , which is S
When> S ₀ , the process proceeds to the step by determining the step, and it is determined whether or not the driving force control flag is “1”. However, when S> S ₀ is just reached, the process of the step is performed. Since "1" is set, the driving force control flag is determined to be "1". Therefore, it is determined whether or not the time value T, which is the content of the timer 4q, is larger than the predetermined time T ₀ by moving to the step, but the predetermined time still remains.
Assuming that T ₀ has not elapsed, it is determined that T ≦ T ₀ , so 1 is added to the timer 4q in the next step.
Then, the processes of steps ,,, ... are repeated until the time value T becomes equal to or greater than the predetermined time T ₀ , and when T> T ₀ , the process moves from step to step and the driving force control flag is set to “0”. After resetting and clearing the timer 4q to 0, the process proceeds to the step.

In the above embodiment, the lockup control signal, the cutback control signal, the OD control signal, and the downshift control signal are used as signals for controlling the operating state of the automatic transmission.
Although the present invention is configured to output control signals of the same class at the same time, the present invention is not limited to this, and it is sufficient that at least one or more control signals of the above four types of signals are output. Of course.

In the above embodiment, the driving force of the engine is reduced by closing the throttle valve 17, but the invention is not limited to this. For example, the ignition timing may be adjusted or the fuel supply amount may be adjusted. You may Further, the control device 3 is not limited to the above configuration,
It can also be composed of electronic circuits such as an adder circuit, a subtractor circuit, a comparison circuit, and a logic circuit.

Furthermore, in the above embodiment, the step motor 16 is used as the driving force control means, but the driving force control means is not limited to this. For example, a digital servo motor and a rotary encoder attached to its rotary shaft may be used. You can Further, in the above embodiment, the example of the rear-wheel drive vehicle has been described, but it goes without saying that the present invention can be applied to the front-wheel drive vehicle.

〔The invention's effect〕

As described above, according to the present invention, the automatic transmission, the slip detecting means for the driving wheels, the driving force control means that can change the engine driving force according to the slip state, and the driving force control means are driven. Control signal output means for outputting a control signal for controlling an operating state of the automatic transmission in a direction in which the driving force transmitted from the engine to the driving wheels is maintained or increased when operating in the force decreasing direction. Since the driving force control device for a vehicle with an automatic transmission is configured by
Even in a vehicle with an automatic transmission, the braking force due to the reduction of the driving force of the engine can be effectively transmitted to the drive wheels. Therefore, the slip of the drive wheels can be suppressed early, and therefore, the vehicle can be recovered from the slip state at an early stage, and the running stability of the vehicle can be secured.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention, FIG. 2 is a schematic explanatory view showing an embodiment of the present invention, and FIGS. 3 to 5 are examples of processing procedures of a control device according to the present invention. It is a flowchart which respectively shows. 1 ... Accelerator potentiometer, 2 ... Accelerator pedal, 3 ... Control device, 4 ... Microcomputer, 4a
...... Interface circuit, 4b …… Arithmetic processing unit, 4c ……
Storage device, 5 ... A / D converter, 6 ... F / V converter, 7 ...
Motor drive circuit, 8,9 ... rear wheel (driving wheel), 10 ... rear wheel rotation speed detector (driving wheel rotation speed detecting means), 11,12 ... front wheel (non-driving wheel), 13,14 ... … Front wheel speed detector (non-driving wheel speed detection means), 16 …… step motor, 17 …… throttle valve, 20 …… transmission control circuit, 21 …… automatic transmission

Claims (4)

[Claims] 1. An automatic transmission capable of automatically changing a gear ratio of a transmission, and slip detection means for detecting a slip state of drive wheels driven through the automatic transmission and outputting a slip detection signal thereof. And a drive force control means capable of changing the drive force of the engine according to the slip state of the drive wheels based on the slip detection signal, the drive force control device for a vehicle with an automatic transmission, comprising: A control signal output means is provided for outputting a control signal for controlling the operating state of the automatic transmission so as to maintain or increase the driving force transmitted from the engine to the driving wheels during the force reduction control. A drive force control device for a vehicle with an automatic transmission, characterized in that: 2. The automatic transmission has a lockup mechanism capable of directly connecting the torque converter thereof, and
The driving force control of a vehicle with an automatic transmission according to claim 1, wherein the control signal output means outputs the control signal for operating the lock-up mechanism or for holding the operation thereof. apparatus. 3. The automatic transmission has a hydraulic pressure control device for shifting the transmission thereof, and the control signal output means holds the line pressure of the hydraulic pressure control device at a pressure before cutback. The driving force control device for a vehicle with an automatic transmission according to claim 1, wherein the control signal is output. 4. The control signal output means outputs the control signal for holding or increasing the gear ratio of the transmission before the start of the driving force control at the start of the driving force control. A driving force control device for a vehicle with an automatic transmission according to item 1.