JP2625945B2 - Vehicle drive wheel slip control system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drive wheel slip control device for a vehicle equipped with a shift point control device that controls a shift point of an automatic transmission by electronic control.

(Prior Art) Conventionally, a second throttle valve driven by an actuator is provided separately from a first throttle valve by an accelerator operation, and a drive wheel slip control device that suppresses a drive wheel slip by controlling opening and closing of the second throttle valve. For example, there is known an apparatus as described in Japanese Patent Application Laid-Open No. 62-45944.

This conventional device controls the rotation of the drive wheels by engine output control (open / close control of a second auxiliary throttle valve) so that the frictional force between the tires of the drive wheels and the road surface increases during vehicle acceleration. Like that.

Further, as a shift point control device for an automatic transmission, for example, "Automotive Engineering Encyclopedia Volume 9 Power Transmission Device"(1980;
An apparatus as described on pages 238 to 245 of Sankaido Co., Ltd.) is known.

This conventional device is configured to determine a shift point determined based on a vehicle speed sensor and a throttle opening sensor, and a shift point characteristic previously set as shift information relating to a vehicle speed and a throttle opening detection value and a vehicle speed and a throttle opening. To achieve this, the shift point control of the automatic transmission is performed by electronic control.

(Problems to be Solved by the Invention) However, the conventional drive wheel slip control device and the shift point control device of the automatic transmission are linked to each other as not disclosed in Japanese Patent Application Laid-Open No. 62-45944. Since there was no relationship and the controls were performed independently of each other, if a shift-up operation or a shift-down operation was performed by a command from the shift point control device, a response delay of the engine output would be accompanied. There has been a problem that wheel spin occurs and vehicle stability and acceleration power deteriorate.

Here, the reason why wheel spin occurs at the time of upshift and the reason that wheel spin occurs at the time of downshift will be described.

First, the rotational motion of the wheel is represented by the following equation (see FIG. 8).

I · = T _E -μ · W where I is the rotational moment of inertia of the powertrain system from the engine flywheel to the wheel, is the wheel rotational angular velocity, _TE is the driving torque, μ is the road surface friction coefficient, and W is the wheel load. It is.

Since the wheel spin occurs when traveling on a road surface having a small road surface friction coefficient μ, if μ · W ≒ 0, the above equation becomes I · = T _E.

(At the time of upshifting) At the time of upshifting, since the gear ratio becomes small, the rotational inertia moment I becomes small, and the engine speed, which tends to increase after the upshift, decreases with a response delay of the engine output.

However, while the rotational moment of inertia I becomes smaller from the time of upshifting, the drive torque T _E remains almost constant with almost no torque fluctuation immediately after the upshift due to response delay, similarly to the engine speed. Therefore, the wheel rotation angular velocity increases from the above equation, that is, wheel spin occurs.

(During downshifting) When the driver fully depresses the accelerator for intermediate acceleration from a steady running state, downshifting occurs due to shift point characteristics.

At this time, the rotational inertia moment I increases with an increase in the throttle opening, and the engine speed rapidly increases due to a delay in engine response.

After downshifting, the increase in the driving torque T _E by the engine speed jump occurs, the driving torque
Increase in T _E is to overcome the increase in the rotational moment of inertia I, as a result, the wheel rotation angular velocity from the above equation is increased, i.e., wheel spin occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem, and prevents a wheel spin accompanying a shift-up and a cyst down by advancing a drive torque reduction control at the time of a shift-up and a cyst-down. It is an object of the present invention to develop a drive wheel slip control device for a vehicle that can improve vehicle stability and acceleration force.

(Means for Solving the Problems) In order to solve the above problems, a drive wheel slip control device for a vehicle according to the present invention employs a throttle for detecting a valve opening of a throttle valve as shown in a claim correspondence diagram of FIG. Opening degree detecting means a and vehicle speed detecting means b for detecting vehicle speed
And a speed change actuator d of the automatic transmission to obtain a speed ratio determined based on a vehicle speed detection value V and a throttle opening detection value TH, and a speed change characteristic c preset as speed change information relating to the vehicle speed and the throttle opening. A speed change control device f including a speed change control circuit e for outputting a speed change command signal (S); a drive torque increasing / decreasing means g capable of increasing / decreasing a drive torque to drive wheels separately from the throttle valve; A drive for outputting a drive torque increase / decrease command signal (T) to an actuator i of a drive torque increase / decrease means g based on a drive wheel slip detection value SL for suppressing the drive wheel slip and a drive wheel slip detection means h for detecting a situation. In a vehicle equipped with a drive wheel slip control device k having a wheel slip control circuit j, the drive wheel slip control circuit j The upshift command signal (AS) and downshift command signal (DS) output from the control circuit e are taken as input signals, and when these shift command signals are input, priority is given to the drive torque reduction control based on the drive wheel slip detection value SL. Then, the circuit is provided with a drive torque reduction control unit 1 that uses both the upshift command signal (AS) and the downshift command signal (DS) as the start signal of the drive torque reduction control.

(Operation) The shift control circuit e obtains the gear ratio determined based on the vehicle speed detection value V and the throttle opening degree detection value TH, and the shift characteristic c preset as the shift information on the vehicle speed V and the throttle opening TH. The shift control is performed by the shift command signal (S) output to the shift actuator d of the automatic transmission.

The upshift command signal (AS) and downshift command signal (DS) output from the shift control circuit e are taken as input signals by the drive wheel slip control circuit j, and the drive torque reduction control section of the drive wheel slip control circuit j 1, when these shift command signals are input, the upshift command signal (AS) and the downshift command signal (DS) are prioritized over the drive torque reduction control based on the drive wheel slip detection value SL.
In both cases, drive torque reduction control is performed as a start signal of drive torque reduction control.

Therefore, the drive torque reduction control is started prior to the occurrence of the excessive drive wheel slip accompanying the upshift or the downshift, and the control is performed after the drive wheel slip occurs. On the contrary, the occurrence of wheel spin accompanying the upshift or downshift is prevented beforehand.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

 First, the configuration will be described.

As shown in FIG. 2, a vehicle to which the drive wheel slip control device A of the embodiment is applied includes an engine 1, an automatic transmission 2,
The automatic transmission 2 includes a propeller shaft 3, a differential 4, rear drive shafts 5 and 6, rear wheels 7 and 8, and front wheels 9 and 10.

The shift point control device B includes a first shift solenoid 23 and a second shift solenoid as shift actuators provided in the control valve unit 22 of the automatic transmission 2.
24, a vehicle speed detection value V _R and the first throttle opening detection value TH ₁ for both shift solenoids 23 and 24, the shift point characteristic 26 which is previously set as the shift information on the vehicle speed V and the throttle opening TH (the A shift point control circuit 25 that outputs shift command signals (S ₁ ) and (S ₂ ) to obtain a shift point determined based on FIG. 3).

The shift point control circuit 25 includes, as internal circuits, an input circuit 25a that converts an input signal into a digital signal or the like, and a CPU 25b (central processing unit) as a central processing unit.
Unit), a memory 25c such as a RAM or a ROM, and an output circuit 25d for converting into a predetermined analog signal or the like.

Wherein the input circuit 25a, a vehicle speed detection value V _R from the vehicle speed sensor 19 provided on the output shaft of the automatic transmission 2, the first throttle opening detection value TH from the first throttle opening degree sensor 20
₁ is input.

From the output circuit 25d, the shift command signal (S ₁ ),
Along with (S ₂ ), the upshift command signal AS and the downshift command signal DS are output to the drive wheel slip control circuit 16 described later.

The drive wheel slip control device A controls a second throttle valve 14 provided in an intake passage 13 of the engine 1 in series with a first throttle valve 12 interlocked with an accelerator pedal 11, and opens and closes the second throttle valve 14. The throttle motor 15 (actuator) to perform
A drive wheel slip control circuit 16 which outputs a second valve opening / closing command signal (T) to suppress slip of the rear wheels 7 and 8
And

The drive wheel slip control circuit 16 includes, as an internal circuit,
An input circuit 16a for converting an input signal into a digital signal or the like,
CPU 16b (central processing unit) as central processing unit and memory 16c such as RAM or ROM
And an output circuit 16d for converting into a predetermined analog signal or the like.

The input circuit 16a is provided with the right front wheel speed detected value V _FR from the right front wheel speed sensor 17, a left front wheel speed detected value V _FL of the left front wheel speed sensor 18, the output shaft of the automatic transmission 2 vehicle speed detecting value V _R from the vehicle speed sensor 19, a first throttle opening detection value TH ₁ from the first throttle position sensor 20, the second throttle opening detection value from the second throttle position sensor 21
And TH _2, upshift command signal AS and the downshift command signal DS is input.

The control program of the drive wheel slip control circuit 16 includes an upshift command signal AS and a downshift command signal.
At the time of input of DS, the upshift command signal AS and the downshift command signal DS are changed to a start signal of the drive torque reduction control by the closing operation of the second throttle valve 14 in preference to the drive torque reduction control based on the drive wheel slip ratio S. A drive torque reduction control process is performed.

 Next, the operation will be described.

First, the flow of the shift point control operation in the shift point control circuit 25 will be described with reference to the flowchart shown in FIG.

In step 100, the vehicle speed detection value V _R to the first throttle opening detection value TH ₁ is read.

In step 101, a vehicle speed detection value V _R and the first throttle opening detection value TH _1, the current shift point N _N by the shift point characteristic 26 (shift position) is determined.

In step 102, it is determined whether N _N > N _N-1 (previous shift point), that is, whether it is during an upshift, and if YES, the process proceeds to step 103, where the upshift command signal AS outputs a drive wheel slip control circuit. Output to 16.

In step 104, it is determined whether or not N _N <N _N-1 , that is, whether or not a downshift is being performed.
The downshift command signal DS is output to the drive wheel slip control circuit 16.

Incidentally, the same current shift point N _N is the shift point N _N-1 of the previous, when the shift position is maintained, step from step 104 106
Proceed to.

In step 106, the shift signal determined shift point N _N is obtained is output to both the shift solenoids 23 and 24.

In step 107, the shift point N _N is rewritten into N _N-1.

Next, the flow of the slip suppression control operation in the drive wheel slip control circuit 16 will be described with reference to the flowchart shown in FIG.

In step 200, the right front wheel speed detected value V _FR and the left front wheel speed detected value V _FL and the vehicle speed detection value V _R to the first throttle opening detection value TH ₁ and the second throttle opening detection value TH ₂ and upshift command signal A
S and the downshift command signal DS are read.

In step 201, the front wheel speed detected value V _F is determined by the average value calculation between the right front wheel speed detected value V _FR and the left front wheel speed detected value V _FL, by the front wheel speed detected value V _F and the vehicle speed detection value V _R The drive wheel slip ratio S is obtained by calculation.

In step 202, it is determined whether or not the upshift command signal AS or the downshift command signal DS is being read. If it is not the time of reading these command signals, the process proceeds to step 203 and thereafter.

In step 203, it is determined whether the vehicle is not controlled (FLAG · T = 0) or is controlled (FLAG · T = 1) based on the drive wheel slip control signal FLAG · T indicating whether or not the drive wheel is in the slip control. .

When FLAG · T = 0 in step 203, the process proceeds to steps 204 and 205, and the start condition of the drive wheel slip control is determined.

That is, the slip ratio S is the set value S ₂ or more (Step 20
4), when the first throttle opening detection value TH ₁ is satisfied fully closed (not TH _MIN) (step 205), as both conditions, the process proceeds to step 206, the FLAG · T = 0 FLAG · T = 1
To start the drive wheel slip control.

When the control is rewritten to FLAG · T = 1 in step 206, there is no reading of the upshift command signal AS or the downshift command signal DS in step 202, or the rewriting to FLAG · T = 0 in step 212 at the time of starting the control. As far as possible, the process proceeds from step 203 to step 207 and thereafter, and drive wheel slip control for controlling the opening and closing of the second throttle valve 14 is performed.

In step 207, the threshold value of the slip ratio S is determined.

That is, when it is determined that S ≧ S ₂ in step 207 step 208
Then, a valve closing command for operating the second throttle valve 14 in the closing direction is output to the throttle motor 15.

When it is determined in step 207 that S ₁ <S <S ₂ , the process proceeds to step 209, and the second motor to the throttle motor 15 at that time is
A valve holding command for holding the throttle valve 14 is output.

Further, if it is determined that S ≦ S ₁ in step 207 step 210
Then, a valve opening command for operating the second throttle valve 14 in the opening direction is output to the throttle motor 15.

When the occurrence of the drive wheel slip is suppressed and the valve opening TH ₂ of the second throttle valve 14 is fully opened (TH _MAX ), the end condition of the drive wheel slip control is satisfied in step 211, and in step 212 the FLAG・ T = 1 is FLAG
-Rewritten to T = 0.

In step 202, the upshift command signal A
If it is determined that S or the downshift command signal DS is being read, the process proceeds to step 213 and subsequent steps.

In step 213, a valve closing command for operating the second throttle valve 14 in the closing direction is output to the throttle motor 15.

In step 214, the valve closing command count value C _N is one by one adder.

In step 215, whether the valve closing command count value C _N is set count value C _NO or it is determined.

This is because that initiated the drive wheel slip control on the basis of up-shift command signal AS or downshift command signal DS, when the slip ratio S is converged not exceed the threshold value S _2, the normal drive wheel slip This is to return to control.

In step 216, whether the slip ratio S is the threshold value S ₂ or more is determined, steps in the case of S <S ₂ 213
To the return, the closing operation of the second throttle valve 14 are repeated, and if it is S ≧ S ₂ proceeds to step 217.

Then, in step 217, FLAG · T = 0 is set to FLAG · T
After rewriting T = 1, step 200 to step 203 →
The process proceeds to the normal drive wheel slip control that proceeds to step 207 and subsequent steps.

Next, regarding the drive wheel slip control operation in the embodiment,
Upshift (Fig. 6) and downshift (Fig. 7)
And will be described separately.

In addition, in the turning motion of the wheel, since the wheel spin occurs when traveling on a road surface having a small road surface friction coefficient μ, μ · W ≒
The following is described assuming that the motion equation is 0 and I · = T _E.

(A) Upshift As shown in FIG. 6, when the first throttle valve 12 accelerates while maintaining the valve opening at a high valve opening,
As can be seen from the shift point characteristic 26 in FIG. 3, the vehicle speed eventually shifts from the second speed to the third speed.

When the normal slip suppression control is performed based on the slip ratio S at the time of this shift-up, the second control shown in FIG.
As shown in the dotted line portion of the slot opening characteristic, since the closing operation of the second throttle valve 14 is started from the time point of time t _2, the
From the time of shift-up will control the beginning of Δt time delay at time t _1, as shown in the dotted line portion of the engine speed characteristic of FIG. 6, after the engine speed has increased significantly after the upshift, suddenly drops I do.

Thus, while comprising the rotational inertia moment I of the gear ratio becomes smaller decreases during upshifting, the driving torque T _E, like engine speed, almost little torque variation at the time immediately after the shift-up by a response delay since remains constant, the wheel rotation angular velocity from the above equation is increased, i.e., as shown in the dotted line portion of the V _R characteristics of Figure 6, wheel spin due to excessive slippage of the driving wheels occurs.

However, in the case of the embodiment device, as soon as the drive slip control circuit 16 inputs the upshift command signal AS,
Since the closing operation of the second throttle valve 14 at time t ₁ is started, the control start and become premature Δt time compared to the time of time t _2, the as shown in the solid line portion of the engine speed characteristic of Figure 6, Rotational speed fluctuations after an upshift of the engine rotational speed are reduced.

Thus, as with the engine speed driving torque T _E, the torque varies in a direction to decrease immediately after shift-up, because a significant increase in the wheel rotational angular velocity is suppressed, indicated by the solid line portion of the V _R characteristics of Figure 6 Thus, excessive slip of the drive wheels is suppressed, and the occurrence of wheel spin is prevented beforehand.

Incidentally, the slip ratio S is higher from the point of time t ₃ when exceeding the threshold value S _2, the normal drive wheel slip control based on the slip ratio S is performed.

(B) At the time of downshifting For intermediate acceleration from steady driving, the driver fully depresses the accelerator to the kickdown area,
As shown in the first throttle opening degree characteristic of FIG. 7, when the first throttle opening opens from theta ₁ to the theta _2, downshift to the third view of the shift point characteristic 26 by 3 gear to the second gear is Occurs.

When the normal slip suppression control is performed based on the slip ratio S at the time of the downshift, the second control shown in FIG.
As shown in the dotted line portion of the slot opening characteristic control starting from the time point t ₅ because since the closing operation of the second throttle valve 14 is started, from the time of shift-down at time t ₄ Delta] t 'time delay As shown by the dotted line portion of the engine speed characteristic in FIG. 7, the engine speed rapidly rises due to a response delay of the engine after the engine speed upshifts and then drops.

Therefore, at the time of downshifting, the rotational inertia moment I increases as the throttle opening increases,
Increase of the driving torque T _E by rapid increase in engine speed occurs, the increase in the driving torque T _E is rotational inertia moment I
Since that will overcome the increase in the wheel rotational angular velocity from the above equation is increased, i.e., as shown in the dotted line portion of the V _R characteristics of Figure 7, wheel spin due to excessive slippage of the driving wheels occurs.

However, in the case of the embodiment device, as soon as the drive slip control circuit 16 inputs the upshift command signal DS,
Since the closing operation of the second throttle valve 14 is started at time t _4, as compared to at time t ₅ becomes control start premature Delta] t 'time, as shown by the solid line portion of the engine speed characteristic of Figure 7 Thus, the gradient of the engine speed increase after downshifting the engine speed is reduced.

Therefore, rise of the drive torque T _E is suppressed similarly to the engine speed, because there is no exceed the rotational moment of inertia I of the amount of increase in the driving torque T _E increases significantly, the Figure 7
As shown by the solid line portion of the V _R characteristic, an excessive slip of the driving wheels is suppressed, generation of wheel spin is prevented.

Incidentally, the slip ratio S is higher from the point of time t ₆ which exceeds the threshold value S _2, the normal drive wheel slip control based on the slip ratio S is performed.

As described above, in the drive wheel slip control device A according to the embodiment, during the control program of the drive wheel slip control circuit 16, when the upshift command signal AS or the downshift command signal DS is input, the drive A drive torque reduction control process in which the upshift command signal AS or the downshift command signal DS is used as a start signal of the drive torque reduction control by the closing operation of the second throttle valve 14, prior to the drive torque reduction control based on the wheel slip ratio S. Is built in,
The effect of being able to prevent the wheel spin accompanying the upshift and downshift can be obtained beforehand, and this effect can improve the stability and the acceleration force of the vehicle. However, the specific configuration is not limited to this embodiment, and any changes or the like within a range not departing from the gist of the present invention are included in the present invention.

For example, in the embodiment, as an example of the drive wheel slip control device, an example of opening and closing control of a second throttle valve provided in series with the first throttle valve has been described. The means is not limited to the embodiment as long as it is a means capable of controlling the increase or decrease of the drive torque of the drive wheels, such as control for applying a braking force or a combination thereof.

In an automatic transmission having an overdrive release switch, an overdrive release signal may be included as a downshift command signal.

The drive torque reduction control by the shift command signal
The operation may be performed only during the driving wheel slip control. In this case, the fact that the driving wheel slip control is being performed is indirect information that the vehicle is traveling on a low road surface friction coefficient road. It is possible to achieve both the prevention of wheel spin on roads and the prevention of vehicle deceleration on roads with a high road friction coefficient where wheel spin is unlikely to occur. In the case of a device having a road surface friction coefficient detecting means, the normal drive wheel slip control and the control by the shift command may be selected according to the magnitude of the road surface friction coefficient.

In addition, when performing drive torque reduction control using an upshift signal or a downshift signal, the amount of drive wheel slip is predicted based on the vehicle speed, engine speed, throttle opening, and the like at that time, and the predicted value is determined according to the predicted value. The reduction width and the reduction speed of the driving torque may be determined.

Further, the specific contents of the drive wheel slip control and the shift point control are not limited to the embodiment.

(Effects of the Invention) As described above, in the vehicle drive wheel slip control device of the present invention, the upshift command signal and the downshift command signal output from the shift control circuit are taken as input signals, At the time of inputting these shift command signals, the drive torque reduction control unit that sets both the upshift command signal and the downshift command signal as the start signal of the drive torque reduction control in preference to the drive torque reduction control based on the drive wheel slip detection value. Because of this circuit, the effect of being able to prevent wheel spin associated with upshifting and downshifting can be obtained.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a drive wheel slip control device for a vehicle according to the present invention, FIG. 2 is an overall view showing a vehicle to which a drive wheel slip control device for a vehicle according to an embodiment is applied, and FIG. FIG. 4 is a shift characteristic diagram set in the apparatus, FIG. 4 is a flowchart showing a flow of a shift control operation in the embodiment apparatus, FIG. 5 is a flowchart showing a flow of a drive wheel slip control operation in the embodiment apparatus, FIG. 6 is a time chart showing a drive wheel slip control and a shift control at the time of an upshift in the embodiment apparatus, and FIG. 7 is a time chart showing a drive wheel slip control and a shift control at the time of a downshift in the embodiment apparatus. FIG. 8 is an explanatory view of the rotational movement of the wheel. a: throttle opening detection means b: vehicle speed detection means c: shift characteristics d: shift actuator e: shift control circuit f: shift control device g: drive torque increasing / decreasing means h: drive wheel slip detection Means i: Actuator j: Drive wheel slip control circuit k: Drive wheel slip control device l: Drive torque reduction control unit V: Vehicle speed detection value TH: Throttle opening detection value (S): Shift command Signal SL: Drive wheel slip detection value (T): Drive torque increase / decrease command signal (AS): Upshift command signal (DS): Downshift command signal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display F16H 59:40 59:44 59:46

Claims (1)

(57) [Claims] 1. Throttle opening detecting means for detecting a valve opening of a throttle valve, vehicle speed detecting means for detecting a vehicle speed, a vehicle speed detecting value and a throttle opening detecting value, and speed change information relating to a vehicle speed and a throttle opening. A shift control device including a shift control circuit that outputs a shift command signal to a shift actuator of the automatic transmission to obtain a shift ratio determined based on a shift characteristic set in advance; Drive torque increasing / decreasing means capable of increasing / decreasing the drive torque to the wheels, drive wheel slip detecting means for detecting a slip condition of the drive wheels, and an actuator of the drive torque increasing / decreasing means based on the detected value of the drive wheel slip to suppress the drive wheel slip. A drive wheel slip control device having a drive wheel slip control circuit that outputs a drive torque increase / decrease command signal to the drive wheel slip control device In the vehicle equipped with, the drive wheel slip control circuit captures an upshift command signal and a downshift command signal output from the shift control circuit as input signals, and when these shift command signals are input, the drive wheel slip detection value A drive wheel for a vehicle, comprising a drive torque reduction control unit that sets both an upshift command signal and a downshift command signal as a start signal of the drive torque reduction control in preference to the drive torque reduction control based on the driving torque. Slip control device.