JPH08200113A - Vehicle acceleration slip control device - Google Patents

Abstract

(57) [Summary] [Purpose] At the time of zero start, the acceleration performance is secured, and
When a large slip actually occurs during traveling other than that, slip control is performed so that the slip converges well. [Configuration] reference based on the vehicle acceleration G _B driving torque T _B
And the feedback correction torque T _F according to the slip state amount DVS, when setting the target drive torque T _O necessary to reduce slip, the control time correspondence lower limit that decreases according to the elapsed time t from the start of slip control Value TLM
Multiply T (t) by a coefficient TK (DVS) that decreases as the slip state amount DVS increases, and if necessary, multiply the result TLMT (t) × TK (DVS) by the maximum allowable value according to the vehicle speed V _B. A value limited to T _MAX (V _B ) or less is set as the drive torque lower limit value TLMIT (t, DVS, V _B ) and the target drive torque T _O is regulated based on this drive torque lower limit value TLMT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration slip control device for a vehicle, which is capable of ensuring a starting acceleration at a zero start and is also an overtaking acceleration on a road surface having a low μ (coefficient of friction). It is devised so that the slip can be quickly converged when the road surface condition changes from high μ to low μ.

[0002]

[Prior art]

<Outline of Acceleration Slip Control> When the vehicle is traveling on a slippery road such as a snowy road, if the driving torque is applied too much, the driving wheels will slip and the grip force of the tire will decrease, resulting in acceleration and maneuverability. Will decrease. In order to deal with such a situation, an acceleration slip control device called a so-called traction control device has been developed and put into practical use.

The traction control device detects the slip state amount of the driving wheels (a slip state amount detecting method will be described later), and when the slip state amount is large, regardless of the amount of depression of the accelerator pedal by the driver, The output of the engine is suppressed compulsorily and promptly to reduce the drive torque (a method for adjusting the drive torque will be described later). By forcibly reducing the drive torque in this way, slip is suppressed and the starting and acceleration characteristics on slippery road surfaces such as snowy roads are improved.

When the traction control device is applied to a two-wheel drive (2WD) vehicle, the slip state quantity DVS is detected as follows. Taking a front-wheel drive vehicle as an example, first, a target drive wheel speed (which has a 1: 1 correlation with a vehicle body speed (vehicle speed) V _B ) V _OT is calculated based on a rear wheel (driven wheel) speed. (The calculation method will be described together in the embodiments of the present invention). Next left and right front wheels (driving wheels)
The average driving wheel speed V _FX is calculated by averaging the speeds of the above. Then, the target drive wheel speed V _OT is subtracted from the average drive wheel speed V _FX to detect the slip state amount DVS.

Further, there are the following drive torque adjusting means for reducing the drive torque to suppress the slip. Throttle control (close the throttle valve of the intake system) Ignition timing retard control (delay the ignition timing of the spark plug) Fuel control (fuel cut and fuel injection amount control) Cylinder number control (a predetermined number of multiple cylinders are closed Brake control (brake is applied to suppress slip)

Traction control devices that are currently in practical use often use a mechanism that combines throttle control and ignition timing retard control. According to the throttle control, the engine output can be smoothly and widely controlled. However, if a sudden slip occurs when the vehicle starts suddenly or when the road surface changes suddenly from a dry road (high μ road) to a frozen road (low μ road), throttle control cannot sufficiently suppress the steep slip. . Therefore, when a steep excessive slip occurs, the ignition timing retard control is temporarily activated according to the magnitude of the slip to suppress the steep slip with good responsiveness.

In the traction control device that combines the throttle control and the ignition timing retard control, the following two sets of controls (start control to reduce drive torque) and reset (end control to restore drive torque) are performed. Like this. (1) The throttle control is set when the slip state amount DVS becomes larger than a preset value, and the throttle control is reset when the slip state amount DVS becomes smaller than the preset value. (2) In ignition timing retard control, slip state quantity DV
S / S and the slip ratio GDVS obtained by differentiating the slip state amount DVS are set and reset.
That is, the slip state amount DVS and the slip ratio GDVS
Is set when both are larger than a predetermined value, and is reset when one of the slip state amount DVS and the slip rate GDVS is decreased to some extent and the other is significantly decreased.

Here, the outline of the slip suppression control by the traction control device will be described. The details of the slip control will be described together with the embodiment of the present invention.
To the slip suppression control is first vehicle speed as well as calculating the reference driving torque T _B in order to maintain the (vehicle body speed) V _B, the feedback drive torque excess causing the slip occurrence correction torque T _F Is calculated based on the slip state amount DVS. Next, the reference drive torque T _B
The target drive torque T _O is obtained by subtracting the feedback correction torque T _F from the target drive torque T _O
It will be reduced to _O. As the torque adjusting means in this case, the above-mentioned throttle control, fuel control, cylinder number control, and brake control are used. Such a drive torque to the target driving torque T _O, the occurrence of the slip is suppressed by reducing.

The feedback correction torque T _F is obtained, for example, by calculating the slip state amount DVS by PID (proportional / integral / derivative) calculation. The calculation formulas and coefficients used for PID calculation are the vehicle running. It is set on the condition that the quick response and stability of the control can be obtained.

<Lower limit regulation for conventional target drive torque> If the drive torque is directly reduced to the target drive torque T _O obtained by subtracting the feedback correction torque T _F from the above-mentioned reference drive torque T _B , the vehicle speed V _B becomes zero at zero start. Therefore, the reference drive torque T _B is not accurately determined, the target drive torque T _O becomes extremely small, and the starting acceleration of the vehicle becomes dull, and the vehicle cannot be started especially on an uphill road. As a countermeasure against this, as disclosed in Japanese Patent Laid-Open No. 2-70939 or Japanese Patent Laid-Open No. 4-66735, there is known a technique of setting a lower limit value to prevent the reduced driving torque from becoming too small. Has been.

In the technique disclosed in Japanese Patent Laid-Open No. 2-70939,
A lower limit value is set for the target drive torque, the lower limit value is set to a large value near the start of the slip control, and then it is changed to a small value according to the elapsed time. Alternatively, the lower limit value is set to a large value when the vehicle speed is near zero, and is changed to a small value as the vehicle speed increases.

In the technique disclosed in Japanese Patent Laid-Open No. 4-66735,
A lower limit is set for the throttle opening, and the lower limit is set to a large value when the vehicle speed is near zero, and is changed to a smaller value as the vehicle speed increases.

[0013]

In the technique of changing the lower limit value of the target drive torque according to the elapsed time from the start of the slip control, the lower limit value near the start of the control is set at the time of zero start, especially on the slope start. Since a large driving torque is required to ensure sufficient start acceleration, it is necessary to set a large value suitable for this. Therefore, in cases other than zero starting, for example, when over-accelerating on a low μ road or when a large slip actually occurs during running such as when changing from a high μ road to a low μ road, the torque as large as zero starting Despite being unnecessary, the target drive torque at the start of slip control is too large, and conversely the convergence of slip reduction deteriorates.

On the other hand, in the technique of changing the lower limit value of the target drive torque or the throttle opening according to the vehicle speed, the magnitude of the vehicle speed itself does not have a one-to-one relationship with the slip, and therefore, the lower limit depends only on the vehicle speed. Even if the value is changed, a sufficient effect cannot be obtained.

In view of the above-mentioned problems of the prior art, an object of the present invention is to ensure a sufficient starting acceleration at the time of zero start, and at the time of overtaking acceleration on other low μ roads or at high μ.
An object of the present invention is to provide an acceleration slip control device for a vehicle, which can quickly converge a slip when a large slip actually occurs such as when the road changes to a low μ road.

[0016]

Means for Solving the Problems A first method for solving the above problems is described below.
The configuration of the invention of claim 1 is provided with a drive torque adjusting means capable of adjusting the drive torque of the vehicle, and when the drive torque of the vehicle is reduced according to the slip generated on the drive wheels, a predetermined lower limit value is provided to reduce the drive torque. In a vehicle drive control device including means for controlling the drive torque adjusting means so as to regulate the drive torque based on the lower limit value: slip detecting means for detecting a slip state amount generated in the drive wheels;
Lower limit value setting means for setting a drive torque lower limit value according to the magnitude of the slip state amount detected by the slip detection means; and reduction of the slip of the drive wheel based on the slip state amount detected by the slip detection means. Target drive torque setting means for setting the target drive torque necessary for setting the target drive torque and restricting the target drive torque based on the drive torque lower limit value set by the lower limit value setting means when setting the target drive torque; An acceleration slip control device for a vehicle, comprising: output control means for controlling the drive torque adjusting means based on the target drive torque set by the target drive torque setting means.

In addition to the first aspect of the present invention, the target drive torque setting means obtains the reference drive torque based on the acceleration of the vehicle and the slip state amount detected by the slip detecting means. A correction torque is obtained according to the above, and the target drive torque is set by the reference drive torque and the correction torque.

According to a third aspect of the invention, in addition to the second aspect of the invention, the target drive torque setting means limits the reference drive torque based on the drive torque lower limit value.

According to a fourth aspect of the invention, in addition to the second aspect of the invention, the target drive torque setting means limits the target drive torque corrected by the correction torque based on the drive torque lower limit value. Is characterized by.

A fifth aspect of the invention is characterized in that, in addition to the first aspect of the invention, the lower limit value setting means sets the driving torque lower limit value to a smaller value as the slip state amount increases.

According to a sixth aspect of the invention, in addition to the first aspect of the invention: the lower limit value setting means is a lower limit value corresponding to a control time which changes according to an elapsed time after the drive torque adjusting means starts control. Is multiplied by a coefficient that changes according to the slip state amount, and the drive torque lower limit value is set.

According to a seventh aspect of the invention, in addition to the first aspect of the invention, the lower limit value setting means limits the lower limit value of the driving torque to a value equal to or less than a maximum allowable value according to a vehicle speed. .

In addition to the first aspect of the invention, the structure of the eighth aspect of the invention is characterized in that the lower limit value setting means sets the drive torque lower limit value in accordance with the gear stage of the transmission.

According to a ninth aspect of the present invention, in addition to the eighth aspect of the invention, the lower limit value setting means sets the drive torque lower limit value to the case where the forward gear is the first speed and the other gears. It is characterized by setting different values in.

According to a tenth aspect of the invention, in addition to the eighth aspect of the invention, the lower limit value setting means sets the drive torque lower limit value to the case where the gear is the first speed or the reverse gear and other gears. It is characterized by setting different values for and.

[0026]

In the present invention, the drive torque lower limit value is set according to the magnitude of the slip state amount, and the target drive torque is regulated. Therefore, even if the target drive torque at the start of slip control is set high to ensure sufficient start acceleration at zero start, during overtaking acceleration on a low μ road or when the road surface condition changes from high μ to low μ When a large slip actually occurs such as a change, the target drive torque becomes smaller than that at the time of zero start, and the slip is suppressed with good convergence.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<Outline Structure of Intake System, Engine System, and Control System> An intake system, engine system, and control system of an embodiment in which the present invention is applied to a front-wheel drive type automobile will first be described with reference to FIG. . As shown in FIG. 1, the air passes through the air cleaner 101 and the intake pipe 102, and the air flows through the engine 10
3 to the combustion chamber 104. The fuel injected from the injection valve 105 is also sent to the combustion chamber 104, and the air-fuel mixture in the combustion chamber 104 is burned by the ignition of the spark plug 106.

A throttle body 107 is provided in the middle of the intake pipe 102, and a throttle valve 108 for adjusting the amount of intake air is rotatably incorporated in the throttle body 107. When the accelerator pedal 109 is depressed, the throttle valve 108 rotates in the opening direction, and when the foot is released from the accelerator pedal 109, the spring force causes the throttle valve 108 to return to the fully closed state. On the other hand, when the control rod 111 is pulled in the direction of arrow A by the vacuum actuator 110, the throttle valve 108 is forcibly closed according to the pulling amount of the control rod 111 regardless of the operation of the accelerator pedal 109. This vacuum actuator 1
The operating mechanism of 10 will be described later.

A surge tank 112 communicates with the downstream side of the throttle body 107.
A vacuum tank 113 is in communication with 2. on the other hand,
Vacuum tank 113 and vacuum actuator 1
A vacuum solenoid valve 114 is provided between the intake pipe 102 and the vacuum actuator 110, and a ventilation solenoid is provided between a portion of the intake pipe 102 near the air cleaner 101 (a portion at which the pressure is substantially atmospheric pressure) and the vacuum actuator 110. The valve 115 is interposed.

The vacuum solenoid valve 114 is non-excited to be in a closed state, and is excited to be in an open state. On the contrary, the ventilation solenoid valve 115 is in the open state when it is not excited and is in the closed state when it is excited. On the other hand, the vacuum actuator 110 controls the control rod 111 when the internal pressure becomes negative.
The control rod 111 when the internal pressure becomes atmospheric pressure.
Returns to the position defined by the spring built into the vacuum actuator 110. Therefore, solenoid valve 1
The energized states of 14, 115 and the operation of the vacuum actuator 110 are summarized as follows. The solenoid valves 114 and 115 are both de-energized. → The internal pressure of the vacuum actuator 110 is atmospheric pressure. → The control rod 111 is at the position defined by the built-in spring. Both solenoid valves 114 and 115 are excited.
→ The internal pressure of the vacuum actuator 110 is negative. → The control rod 111 is pulled in the A direction.

The pulling position of the control rod 111 in the A direction is determined by duty-controlling the current supplied to the solenoid valves 114 and 115, and the amount of movement of the control rod 111 in the A-direction is determined according to the duty ratio.

The opening / closing operation of the throttle valve 108 will be summarized here. The duty ratio of the current to the solenoid valves 114 and 115 is 0%, and the vacuum actuator 11
When the 0 control rod 111 is in the position defined by the spring, the throttle valve 108 opens in a one-to-one correspondence with the depression amount of the accelerator pedal 109. When the control rod 111 is pulled in the direction A by applying a current to the solenoid valves 114 and 115, the throttle valve 108 is forcibly closed regardless of the depression amount of the accelerator pedal 109. Throttle valve 108
The closing amount corresponds to the moving amount of the control valve 111, and thus the current duty ratio to the solenoid valves 114 and 115.

The engine control unit 201 is
The throttle valve 108 can be forcibly closed by controlling the current supplied to the solenoid valves 114 and 115. As a result, the output of the engine 103 can be reduced. Further, the engine control unit 201 can adjust the ignition timing of the spark plug 106, and by retarding the ignition angle, the engine 10
3 can be reduced. Further, the engine controller 201 can adjust the amount of fuel injected from the injection valve 105, which can reduce the engine output.

The torque control unit 202 is connected to the engine control unit 201 by a communication cable 203. The engine control unit 201 sends an engine state signal to the torque control unit 202, and the torque control unit 202
Sends to the engine control unit 201 information regarding the target drive torque (calculation method will be described later) and the ignition timing retard ratio.

The torque control unit 202 receives signals from various sensors (a specific example will be described later) in addition to the accelerator opening sensor 204 to determine slip as described later.
The target drive torque is calculated and the retard angle ratio is calculated. On the other hand, the engine control unit 201 receives information from sensors such as the throttle opening sensor 205 and the torque control unit 202, and controls the output of the engine 103. Particularly when the engine output is forcibly reduced, the engine control unit 201 increases the duty ratio of the solenoid valves 114 and 115 and delays the ignition timing of the ignition plug 106.

<Structure and Calculation Centering on Torque Control Unit> Next, the torque control unit 20
An example of the configuration and the calculation procedure of the sensors 2 and its peripherals will be described with reference to FIG.

As shown in FIG. 2, the torque control unit 202 includes a right rear wheel speed sensor 251, a left rear wheel speed sensor 252, a right front wheel speed sensor 253, and a left front wheel speed sensor 25.
4, various sensors (not shown) are connected. The right rear wheel speed sensor 251 detects the right rear wheel speed V _RR , the left rear wheel speed sensor 252 detects the left rear wheel speed sensor V _RL , the right front wheel speed sensor 253 detects the right front wheel speed V _FR , Left front wheel speed sensor 2
Reference numeral 54 detects the front left wheel speed V _FL .

The vehicle body speed calculation unit 301 of the torque control unit 202 obtains the vehicle speed, that is, the vehicle body speed V _B by multiplying the right rear wheel speed V _RR and the left rear wheel speed V _RL by a weighting factor and then averaging them. The differentiating unit 302 obtains the acceleration of the vehicle, that is, the longitudinal acceleration G _B along the straight traveling direction of the automobile by differentiating the vehicle speed V _B. The torque conversion unit 303 obtains the reference drive torque T _B by multiplying the longitudinal acceleration G _B by the vehicle body weight W _b and the effective tire radius r of the front wheels. The correction torque calculation unit 304 obtains the correction torque T _C corresponding to the running resistance and the like, and the addition unit 305
Then, the correction reference torque T _BC is _calculated by adding the correction torque T _C to the reference drive torque T _B.
Give to 7. The correction torque T _C is the sum of the running resistance and the cornering drag torque. The running resistance is obtained based on map data, and tends to increase as the vehicle body speed V _B increases. The cornering drag torque is also obtained based on map data, and tends to increase as the turning angle of the steering shaft increases.

The target drive torque regulation unit 317 limits the corrected reference drive torque T _BC to the drive torque lower limit value TLMT or more set by the lower limit value setting unit 318 and gives it as the regulation reference drive torque T _BCL to the subtraction unit 312. .

As shown in FIG. 3, the lower limit value setting unit 318 comprises a control time corresponding lower limit value setting unit 319, a slip state amount corresponding coefficient setting unit 320, a vehicle speed corresponding upper limit limiting unit 321, and a multiplying unit 322. There is.

The control time corresponding lower limit value setting unit 319 is mainly intended to secure the starting acceleration at the time of zero starting.
As in the patterns A and B illustrated therein, the lower limit value TLMT (t) is set to be smaller according to the elapsed time t (seconds) from the start of slip control (t = 0). Each pattern A,
B is map data. Pattern A is used when the gear position of the transmission is the first speed on the forward side and the reverse speed, and is sufficient to secure the starting acceleration at the time of zero starting when the load is large while 0 ≦ t ≦ 1. Constant at a high value, it is considered that the start has ended when 2 ≦ t, so it is a low value for slip control and constant at a value of 1 ≦ t ≦ 2, so that both acceleration performance during start and slip control are compatible, a high value to a low value The value gradually decreases linearly. Pattern B is used when the shift speed is the second speed or higher on the forward side, and the value is smaller than that of pattern A as a whole. In this way, the lower limit value TLMT (t) corresponding to the control time is varied depending on the shift speed is generally the forward side 1
This is because the speed and the reverse gear are mainly selected at the time of zero start, and the forward second speed and higher are selected after the start. The control time corresponding lower limit value setting unit 319 selects the pattern A or B based on the shift speed information, and the lower limit value TLM corresponding to the elapsed time t after the start of the slip control from the map data of the pattern.
T (t) is set and given to the multiplication unit 322.

The slip state quantity correspondence coefficient setting section 320
The control time support lower limit value TLMT (t) is used to ensure the starting acceleration at the time of zero start, and also when overtaking acceleration on a low μ road or when the road condition suddenly changes from high μ to low μ The main purpose is to improve the slip convergence when a large slip actually occurs in the slip state quantity DVS (Km / h) as shown in the pattern C in FIG.
Is set to be larger, that is, the slip is more severe, the smaller the coefficient TK (DVS) is set. Pattern C is map data. In the pattern C, the slip state amount D
In a small region where VS is below a certain level, the coefficient is fixed to 1 in order to secure the starting acceleration at the time of zero start, and in the region where the slip state amount DVS is above a certain level, a large slip that is actually occurring is suppressed. The coefficient is fixed to a small value (for example, 0.5) in order to achieve good convergence, and during that time, the coefficient is linearly reduced from 1 to 0.5 in order to achieve both slip control and acceleration performance during zero start. The slip state amount correspondence coefficient setting unit 320 sets a coefficient TK (DVS) corresponding to the slip state amount DVS from the map data of the pattern C, and gives it to the multiplication unit 322.

The multiplying unit 332 determines the control time corresponding lower limit value TLM.
By multiplying T (t) by the slip state amount correspondence coefficient TK (DVS), the drive torque lower limit value TLMT (t, DV
S) is calculated. This drive torque lower limit value TLMT (t, D
VS) may be used to limit the correction reference torque T _BC to the same lower limit value TLMT (t, DVS) or more in the target drive torque regulation unit 317. As a result, the target drive torque becomes sufficiently high at the time of zero start and the starting acceleration can be secured, and the target drive torque becomes sufficiently low and the slip convergence becomes good when a large slip actually occurs during traveling.

However, even if the slip state amount DVS is the same, it is desirable to converge the slip earlier as the vehicle speed (vehicle body speed) V _B is higher. This is achieved by the vehicle speed corresponding upper limit limiter 321. As shown in a pattern D in FIG. 3, the maximum allowable value T _MAX (V _B ) is set which becomes smaller as the vehicle speed V _B (Km / h) increases. , Drive torque lower limit value TLM
T (t, DVS) limited to the maximum allowable value T _MAX (V _B ) or less TLMT (t, DVS, V _B ) is set as the final drive torque lower limit value, and the target drive torque regulation unit 317 is set. give. In the pattern D, the maximum allowable value is constant at a sufficiently high value in the ultra-low speed range, and is constant at a sufficiently low value in a somewhat fast range, and during that period, it gradually decreases linearly from a high value to a low value and serves as map data. Vehicle speed upper limit control unit 32
1 is the maximum allowable value T _MAX from the map data according to the vehicle speed V _B
(V _B ) is set, and the drive torque lower limit value is controlled below this.

On the other hand, the multiplication unit 306 multiplies the vehicle body speed V _B by a constant (1.1) to obtain the target drive wheel speed V _OT . The constant value 1.1 was determined based on the following findings. That is, while the vehicle is running, the front wheels (driving wheels) are 10% of the road surface.
It was decided in consideration of the fact that a good degree of maneuverability and acceleration performance will be obtained by slipping to some extent.

The correction speed calculation unit 307 calculates the correction speed V _C. The correction speed V _C is obtained by subtracting the turning correction value from the acceleration correction value. The acceleration correction value is obtained from the map data, and tends to increase stepwise as the value of the longitudinal acceleration G _B increases. The turning correction value is also obtained from the map data, and tends to increase as the lateral acceleration (corresponding to the speed difference between the left and right rear wheels) increases. Then, the adding unit 308 adds the correction speed V _C to the target drive wheel speed V _OT to obtain the corrected target drive wheel speed V _OTC .

The average driving wheel speed calculation unit 309 determines the right front wheel speed V
_The average driving speed V _FX is obtained by averaging _FR and the left front wheel speed V _FL . The subtraction unit 310 subtracts the corrected target drive speed V _OTC from the average drive wheel speed V _FX to obtain the slip state amount DVS.

The feedback correction torque calculation unit 311 multiplies the slip state quantity DVS by a proportional coefficient to obtain a basic proportional correction torque proportional to the slip state quantity DVS, and integrates the slip state quantity DVS to slip. An integral calculation for obtaining an integrated correction torque corresponding to a gradual change in the state amount and a differential calculation for differentiating the slip state amount DVS to obtain a differential correction torque corresponding to a rapid change in the slip state amount. Further, the proportional correction torque, the integral correction torque, and the differential correction torque are added to obtain the feedback correction torque T _F. In the feedback correction torque calculation unit 311, the value of the feedback correction torque T _F becomes optimum during steady running (running other than extremely low speed running), and an arithmetic expression that can suppress slip quickly and stably is provided. It is used to calculate.

In the subtracting section 312, the regulation reference drive torque T
_BCLTo feedback correction torque T_FAnd subtract
Feedback correction reference drive torque T_BCLFAsk for. Further percent
In the calculation unit 313, the feedback correction reference drive torque T
_BCLF(= T_BCL-T_F) Is the total reduction ratio ρ_m・ Ρ_d(Manu
(For Al transmission)
The target drive torque T₀Ask for. Note that ρ_mIs a transformer
Transmission gear ratio, ρ_dIs the differential gear reduction ratio. Note that
In the case of automatic transmission, torque
Converter ratio ρ_TConsidering also, the total reduction ratio is ρ_m・ Ρ_d・ Ρ
_TBecomes Target drive torque T₀Is the acceleration G of the vehicle_BTo
Based drive torque T_B(This is the vehicle speed V_BMaintain
Drive torque lower limit value T_LMT
The torque corresponding to the slip state amount DVS from the torque regulated by
Feedback correction torque T _F(This caused a slip
Corresponding to the torque to be applied). Yo
Engine output to target drive torque T₀Even reduced to
If the vehicle is running,
Large slips that are actually occurring are suppressed with good convergence.
Will be done.

On the other hand, the differentiator 314 determines the slip state quantity D
The slip rate GDVS is obtained by differentiating VS. The retard control set / reset determination unit 315 is preset with conditions for setting (starting) and resetting (ending) the ignition timing retard control. Judgment unit 31
5 is this set / reset condition, slip state amount DV
Based on S and the slip ratio GDVS, it is determined whether to set or reset the ignition timing retard control. When set, the determination unit 315 outputs the retard command L to the engine output reduction requesting unit 316, and when reset, the output of the retard command L is stopped.

The engine output reduction requesting unit 316 (i)
When the traction control switch is turned on by the driver and the traction control is selected (ii) conditions such as the slip state amount DVS and the slip ratio GDVS being equal to or greater than the set values are satisfied, the target drive torque T ₀
And the retard command L to the engine control unit 2
01 to reduce engine output.

The engine control unit 201 is
The throttle valve 108 is forcibly closed by controlling the duty ratio of the current flowing through the solenoid valves 114 and 115 so that the output of the engine 103 becomes the target drive torque T _O. Further, the engine control unit 201 delays the ignition timing of the spark plug 106 according to the retard command L.

<Other Embodiments> Next, another embodiment of the present invention will be described with reference to FIG.

As is clear from a comparison between FIG. 4 and FIG. 2, the vehicle acceleration slip control system according to the present embodiment is different from the previous embodiment (FIG. 2) in that the target drive torque regulating section 317, the running resistance, etc. The difference is that the torque correction addition unit 305 and the feedback correction subtraction unit 312 are moved between the subtraction unit 312 and the total reduction ratio division unit 313. Therefore, this point will be described below.

The subtraction unit 312 subtracts the feedback correction torque T _F obtained by the feedback correction torque calculation unit 311 from the correction reference drive torque T _BC obtained by the addition unit 305 to obtain the feedback correction reference drive torque T _BCF (=
T _BC −T _F ).

The target drive torque regulation unit 317 sets the feedback correction reference drive torque T _BCF to the lower limit value setting unit 318.
The drive torque lower limit value TLMT is set to a value equal to or more than the drive torque lower limit value TLMT, and the calculated reference drive torque T _BCFL is given to the division unit 313.

In the division section 313, the reference drive torque T which has been feedback-corrected as described above and whose lower limit value is regulated is used.
By dividing the _BCFL total reduction ratio to determine the desired driving torque T _O. The target drive torque T _O is the slip state amount D that is the reference drive torque T _B based on the vehicle acceleration G _B.
The target drive torque corrected by the (feedback) correction torque T _F according to VS becomes a value regulated based on the drive torque lower limit value TLMT set by the lower limit value setting unit 318 shown in FIG. Therefore, by reducing the engine output to the target drive torque T _O , similar to the previous embodiment shown in FIG. 2, sufficient starting acceleration at the time of zero start is secured and then overtaking acceleration on a low μ road. When a road surface condition suddenly changes from a high μ to a low μ, a large slip actually occurring during traveling is suppressed with good convergence.

[0059]

As described above in detail with reference to the embodiments, the present invention has the following effects.

According to the first aspect of the invention, the target drive torque for suppressing the slip is regulated by the drive torque lower limit value set according to the magnitude of the slip state amount, so that the start acceleration at the time of zero start is sufficiently secured. Even if the target drive torque at the start of slip control is set high so that a large slip actually occurs when overtaking acceleration on a low μ road or when the road surface condition changes from high μ to low μ. When the slip control is started, the target drive torque at the start of slip control becomes smaller than that at the time of zero start, and slip can be suppressed with good convergence.

The invention of claim 2 is a more specific form of the invention of claim 1, in which the target drive torque is set based on the reference drive torque based on the vehicle acceleration and the correction torque according to the slip state amount. Therefore, basically, the slip can be suppressed by adjusting the drive torque of the vehicle so that the target drive torque is obtained.

The invention according to claim 3 is a more specific form of the invention according to claim 2, in which the reference drive torque is limited based on the drive torque lower limit value before correction by the correction torque. It is possible to reliably achieve the start acceleration performance and the improvement of the slip convergence performance when a large slip is actually occurring.

The invention of claim 4 is a more specific version of the invention of claim 2 as with the invention of claim 3, but the reference drive torque is corrected by the correction torque and then limited based on the drive torque lower limit value. Therefore, also in this case, it is possible to surely achieve the start acceleration at the time of zero start and the improvement of the convergence of the slip when the actual large slip occurs.

A fifth aspect of the present invention is a more specific form of the first aspect of the present invention. The larger the slip state amount, the smaller the drive torque lower limit value. Therefore, when the actual large slip occurs, the convergence is achieved. Slip can be suppressed with good performance.

A sixth aspect of the present invention is a more specific form of the first aspect of the present invention, in which a value that changes according to the elapsed time from the start of slip control is multiplied by a coefficient that changes according to the slip state amount. Since the drive torque lower limit value is set by the above, it is possible to reliably achieve the starting acceleration performance at the time of zero start and the improvement of the slip convergence when an actual large slip occurs.

The invention of claim 7 is a more specific form of the invention of claim 1, wherein the lower limit of the driving torque is limited to the maximum allowable value or less according to the vehicle speed, so that the starting acceleration at the time of zero start is suppressed. It is possible to surely achieve the securing and the improvement of the slip convergence when a large slip actually occurs depending on the vehicle speed.

The invention of claim 8 is a more specific form of the invention of claim 1, and since the lower limit value of the drive torque is set in accordance with the shift speed, slip control can be performed finely.

The invention of claim 9 is a more specific form of the invention of claim 8, in which the lower limit of the drive torque is made different between the first speed and the other speeds on the forward speed side. It is possible to reliably achieve the starting acceleration at the time of starting and the improvement of the convergence of the slip when a large slip actually occurs during traveling according to the vehicle speed.

The invention of claim 10 is a more specific form of the invention of claim 8, in which the lower limit value of the drive torque is made different between the first speed or the reverse gear and the other gears, so that it is zero in the case of forward or reverse. It is possible to reliably achieve the starting acceleration at the time of starting and the improvement of the convergence of the slip when a large slip actually occurs during traveling according to the vehicle speed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an intake system, an engine system, and a control system of a vehicle to which a driving force control device according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a configuration example of a torque control unit used in the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration example and a characteristic example of a lower limit value setting unit.

FIG. 4 is a block diagram showing another configuration example of the torque control unit used in the embodiment of the present invention.

[Explanation of symbols]

101 Air Cleaner 102 Intake Pipe 103 Engine 104 Combustion Chamber 105 Injection Valve 106 Spark Plug 107 Throttle Body 108 Throttle Valve 109 Accelerator Pedal 110 Vacuum Actuator 111 Control Rod 112 Surge Tank 113 Vacuum Tank 114 Vacuum Solenoid Valve 115 Ventilation Solenoid Valve 201 Engine Control Unit 202 Torque control unit 203 Communication cable 204 Accelerator opening sensor 205 Throttle opening sensor 251 Right rear wheel speed sensor 252 Left rear wheel speed sensor 253 Right front wheel speed sensor 254 Left front wheel speed sensor 301 Body speed calculator 302 Differentiator 303 303 Torque Conversion unit 304 Correction torque calculation unit 305 Addition unit 306 Multiplication unit 3 7 Correction speed calculation unit 308 Addition unit 309 Average drive wheel speed calculation unit 310 Subtraction unit 311 Feedback correction torque calculation unit 312 Subtraction unit 313 Division unit 314 Differentiation unit 315 Retard control set / reset determination unit 316 Engine output reduction request unit 317 Target Drive torque control unit 318 Lower limit value setting unit 319 Control time correspondence lower limit value setting unit 320 Slip state amount correspondence coefficient setting unit 321 Vehicle speed correspondence upper limit unit 322 Multiplying unit DVS Slip state amount GDVS Slip rate (change rate of slip state amount) V _OT Target drive wheel speed V _FX Average drive wheel speed V _B Body speed L Retard command

Claims (10)

[Claims] 1. A drive torque control means capable of adjusting a drive torque of a vehicle, wherein a predetermined lower limit value is set when the drive torque of the vehicle is reduced according to a slip generated on a drive wheel, and the drive force is reduced. In a drive control device for a vehicle, which is provided with a means for controlling the drive torque adjusting means so as to regulate the torque based on the lower limit value: a slip detecting means for detecting a slip state amount generated in the drive wheel; A lower limit value setting means for setting a drive torque lower limit value according to the magnitude of the slip state amount detected by the slip detection means; and reducing the slip of the drive wheel based on the slip state amount detected by the slip detection means. In order to set the target drive torque required for this purpose, the lower limit of the drive torque set by the lower limit setting means at the time of setting the target drive torque is set. Target drive torque setting means for restricting the target drive torque based on a limit value; based on the target drive torque set by the target drive torque setting means,
An output control means for controlling the drive torque adjusting means; and an acceleration slip control device for a vehicle. 2. The acceleration slip control device for a vehicle according to claim 1, wherein the target drive torque setting means obtains a reference drive torque based on the acceleration of the vehicle, and the target drive torque setting means responds to a slip state amount detected by the slip detection means. An acceleration slip control device for a vehicle, characterized in that a correction torque is obtained by setting the target drive torque based on the reference drive torque and the correction torque. 3. The acceleration slip control device for a vehicle according to claim 2, wherein the target drive torque setting means limits the reference drive torque based on the drive torque lower limit value. Control device. 4. The acceleration slip control device for a vehicle according to claim 2, wherein the target drive torque setting means limits the target drive torque corrected by the correction torque based on the drive torque lower limit value. A characteristic vehicle acceleration slip control device. 5. The vehicle acceleration slip control device according to claim 1, wherein the lower limit value setting means sets the lower limit value of the drive torque to a smaller value as the slip state amount is larger. Slip control device. 6. The vehicle acceleration slip control device according to claim 1, wherein the lower limit value setting means is a lower limit value corresponding to a control time that changes according to an elapsed time from when the drive torque adjusting means starts control. An acceleration slip control device for a vehicle, wherein the driving torque lower limit value is set by multiplying by a coefficient that changes according to the slip state amount. 7. The vehicle acceleration slip control device according to claim 1, wherein the lower limit value setting means limits the drive torque lower limit value to a value equal to or less than a maximum allowable value according to a vehicle speed. Acceleration slip control device. 8. The acceleration slip control device for a vehicle according to claim 1, wherein the lower limit value setting means sets the lower limit value of the drive torque in accordance with a shift stage of a transmission. Control device. 9. The acceleration slip control device for a vehicle according to claim 8, wherein the lower limit value setting means sets the lower limit value of the drive torque to a value when the forward speed is a first speed and a speed other than that. An acceleration slip control device for a vehicle, which is set to different values. 10. The acceleration slip control device for a vehicle according to claim 8, wherein the lower limit value setting means sets the lower limit value of the drive torque to one of a first speed or a reverse speed and other speeds. The vehicle acceleration slip control device is characterized in that different values are set in.