JPH075048B2 - Vehicle acceleration slip prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an acceleration slip prevention device for a vehicle.

(Prior Art) Conventionally, there is known a traction control device for preventing drive wheel slip during acceleration as disclosed in Japanese Patent Laid-Open No. Sho 61-85248.

(Problems to be Solved by the Invention) In such a conventional traction control device, when the slip of the drive wheel is detected, control for reducing the slip of the drive wheel (traction control) is performed. When the traction control is stopped immediately after the slip is reduced, the drive wheels immediately slip.

The present invention has been made in view of the above points, and an object thereof is to apply a brake to a drive wheel when a slip of the drive wheel is detected and to control a throttle opening so that a torque according to a road surface state or a slip state is obtained. Another object of the present invention is to provide an acceleration slip prevention device for a vehicle, which is designed to prevent the drive wheels from slipping during acceleration.

[Configuration of the Invention] (Means and Actions for Solving the Problem) Drive wheel speed detecting means for detecting drive wheel speed VF, driven wheel speed detecting means for detecting driven wheel speed VB, and torque for reducing drive torque A reduction means and a slip amount DV corresponding to the difference between the driving wheel speed VF and the driven wheel speed VB are calculated,
When at least the slip amount DV is larger than a predetermined value, first means for starting the reduction of the drive torque by the torque reducing means, and the correction torque TP and the slip calculated by multiplying the slip amount DV by a coefficient Kp Integral of the quantity DV (Ki
ΣDV, Ki is a coefficient) to obtain the correction torque TS, the reference torque TG is obtained from the acceleration of the driven wheel speed VB, and the target torque TΦ = TG-KiΣDV-KpDV is set, and at least when the slip amount DV is larger than the set value. Is provided with drive control means for controlling the engine output so as to attain the target torque TΦ and recovering the drive torque, and the coefficient Kp is
A vehicle acceleration slip prevention device characterized in that DV> 0 is smaller than DV <0.

According to this device, when slip is suppressed, the coefficient Kp
Responsiveness is improved by taking a large value.

(Embodiment) A vehicle acceleration slip prevention device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an acceleration slip prevention device for a vehicle. The figure shows a front-wheel drive vehicle. WFR is the front right wheel, WFL
Indicates a front left wheel, WRR indicates a rear right wheel, and WRL indicates a rear left wheel. 11 is the front right wheel (driving wheel)
A wheel speed sensor for detecting the wheel speed VFR of WFR, 12 is a wheel speed sensor for detecting the wheel speed VFL of the front left wheel (driving wheel) WFL, and 13 is a wheel speed VRR of the rear right wheel (driven wheel) WRR. A wheel speed sensor 14 is a wheel speed sensor for detecting the wheel speed VRL of the rear left wheel (driven wheel) WRL. The wheel speeds VFR, VFL, VRR, VRL detected by the wheel speed sensors 11 to 14 are input to the traction controller 15. The traction controller 15 controls to prevent the drive wheels from slipping during acceleration, and the engine 16 has a main throttle valve THm and a sub-throttle valve THs as shown in FIG. At this time, the output is adjusted by operating the main throttle valve THm with the accelerator pedal, and at the time of slip prevention control, the sub-throttle valve THs and the throttle opening Θs are controlled to drive the engine output. Further, 17 is a wheel cylinder for braking the right front wheel WFR, and 18 is a wheel cylinder for braking the front left wheel WFL. The pressure oil is supplied to the wheel cylinder 17 from the hydraulic pressure source 19 through the inlet valve 17i, and the pressure oil is discharged from the wheel cylinder 17 to the reservoir 20 through the outlet valve 17o. Further, the pressure oil is supplied to the wheel cylinder 18 from the hydraulic pressure source 19 through the inlet valve 18i, and the pressure oil is discharged from the wheel cylinder 18 to the reservoir 20 through the outlet valve 18o. Then, the inlet valves 17i and 1
8i, the opening / closing control of the outlet valves 17o and 18o is performed by the traction controller 15.

Next, a detailed configuration of the traction controller 15 will be described with reference to FIG. The wheel speeds VFR and VFL of the drive wheels detected by the vehicle speed sensors 11 and 12 are the average part.
At 21, the average wheel speed (VFR + VFL) / 2 is calculated. At the same time, the wheel speeds VFR and VFL of the drive wheels detected by the wheel speed sensors 11 and 12 are sent to the low vehicle speed selection section (SL) 22 to allow the wheel speed VFR and the wheel speed VFL.
The smaller wheel speed of FL is selected and output. Further, the average wheel speed output from the averaging unit 21 is multiplied by a variable K in the weighting unit 23, and the wheel speed output from the low vehicle height selecting unit 22 is multiplied by (1-K) in the weighting unit 24. , Are respectively sent to the adding section 25 and added. The variable K is a variable K that changes according to the centripetal acceleration G generated when turning as shown in FIGS.
The largest of G, the variable KT that changes according to the time t after the start of the slip control by the brake, and the variable KV that changes according to the vehicle body speed (driven wheel speed) VB are selected. The wheel speed output from the adder 25 is the drive wheel speed VF.
Is sent to the differentiator 26 to calculate the temporal change in the drive wheel speed VF, that is, the drive wheel acceleration GW, and is used when the slip amount DV of the drive wheel is calculated as described later.

Further, the wheel speed VFR of the right drive wheel detected by the wheel speed sensor 11 is sent to the subtraction unit 27 and is subtracted from a reference drive wheel speed VΦ which will be described later.
The wheel speed VFL of the left driving wheel detected at 12 is sent to the subtraction unit 28 and is subtracted from the reference driving wheel speed VΦ which will be described later. The output of the subtraction unit 27 is multiplied by a (0 <a <1) in the multiplication unit 29, the output of the subtraction unit 28 is multiplied by (1-a) in the multiplication unit 30, and then added by the addition unit 31. Then, the slip amount DVFR of the right drive wheel is obtained. Similarly, the output of the subtraction unit 28 is multiplied by a in the multiplication unit 32, and the output of the subtraction unit 27 is (1-
a) After being multiplied, it is added in the adder 34 to be the slip amount DVFL of the left driving wheel. Then, the slip amount DVFR of the right drive wheel is differentiated in the differentiator 35 to calculate its temporal change amount, that is, the slip acceleration GFR, and the slip amount DVFL of the right drive wheel is differentiated in the differentiator 36. The amount of change over time, that is, the slip acceleration GFL is calculated. Then, the slip acceleration GFR
Is sent to the brake fluid pressure change amount (ΔP) calculation unit 37, and the brake fluid pressure change amount ΔP for suppressing the slip acceleration GFR is determined by referring to the GFR (GFL) -ΔP conversion map shown in FIG. Desired. Similarly, the slip acceleration GFL is sent to the brake fluid pressure change amount (ΔP) calculation unit 38, and the GFR (GFL) -ΔP conversion map shown in FIG. 6 is referred to in order to suppress the slip acceleration GFR. The change amount ΔP of the brake fluid pressure is calculated (however, if DV> 6Km / h, the larger of ΔP and 2Kg / cm ² is adopted).
The amount of change ΔP indicates the amount of change in the amount of liquid that flows in or out through the inlet valve 17i (18i) or the outlet valve 17o (18o). That is, when the slip acceleration GFR (GFL) increases, ΔP increases, so that the drive wheels WFR and WFL are braked and the drive torque is reduced.

Further, the amount of change ΔP of the brake fluid pressure for suppressing the slip acceleration GFR output from the ΔP calculator 37 is ΔP−T for calculating the opening time T of the inlet valve 17i and the outlet valve 17o via the switch 39. Converter 4
When the change amount ΔP is positive, the opening time of the inlet valve 17i is calculated, and when the change amount ΔP is negative, the opening time of the outlet valve 17o is calculated. The switch 39 is used to start / stop the drive wheels.
It is closed / opened when the end condition is satisfied. For example, it is closed when all of the following three conditions (1) to (3) are satisfied. (1) Idle SW is off. (2)
The main throttle opening Θm is in the shaded area in FIG. 7.
(3) The slip amount DVFR (DVFL)> 2 and the G switch is on or the slip amount DVFR (DVFL)> 5. The G switch is a switch that is turned on / off depending on the size of GFR (GFL). When GFR (GFL)> 1g, it is turned on, and GFR (GFL) <0.5g.
It is turned off (g is gravitational acceleration). Further, the switch 39 is opened, for example, when any of the following three conditions is satisfied. (1) Idle SW is on. (2) Accelerator SW
Is on. (3) ABS operation. Hereinafter, the opening time T of the inlet valve 17i calculated in the ΔP-T conversion unit 40 is added to the ineffective liquid amount correction value ΔTR under control in the addition unit 41 to be the braking operation time FR of the right drive wheel. Similarly, the amount of change ΔP of the brake fluid pressure for suppressing the slip acceleration GFL output from the ΔP calculator 38 is calculated by using the switch 42 to calculate the opening time T of the inlet valve 18i and the outlet valve 18o ΔP. When the change amount ΔP is positive, the inlet valve 18 is sent to the −T conversion unit 43.
The opening time of i and the opening time of the outlet valve 18o when the change amount ΔP is negative are obtained. This Δ
Inlet valve 18 calculated in the P-T converter 43
The opening time T of i is added to the ineffective liquid amount correction value ΔT _{L being} controlled in the adding section 44, and the braking operation time FL of the left driving wheel is increased.
It is said that In other words, ΔTR (L) = − ΣΔTi + (1/10) ΣΔTo (where ΔTi is the inlet time and ΔTo is the outlet time), and the brake begins to work after increasing the fluid amount, so correct the delay. There is. However, ΔTR
(L) is clipped at 40ms because the delay can be corrected if the maximum is 40ms.

Further, the wheel speeds VRR and VRL of the driven wheels detected by the wheel speed sensors 13 and 14 are sent to the high vehicle speed selection unit (SH) 45, and the larger wheel speed of the wheel speed VRR and the wheel speed VRL is determined. It is selected and output as the vehicle speed VB.

At the same time, the wheel velocities VRR and VRL of the driven wheels detected by the vehicle speed sensors 13 and 14 are the centripetal acceleration G calculation units.
Sent to 46, GY is calculated as the centripetal acceleration G for determining the presence or absence and the degree of turning.

Further, the vehicle body speed VB selected and output by the high wheel speed selecting unit 45 is the vehicle body speed VB by the vehicle body acceleration calculating unit 47.
Is calculated, that is, the vehicle body acceleration B (GB) is calculated.
This calculation of the vehicle body acceleration B is performed by the vehicle body acceleration calculation unit 47 this time.
The vehicle speed VBn input to the vehicle and the previous vehicle acceleration calculation unit 47
It is determined by dividing the difference from the vehicle body speed VBn-1 input to the sampling time T by the sampling time T.

That is, B = GBn = (VBn-VBn-1) / T (1)

That is, the vehicle body acceleration calculation unit 47 calculates the vehicle body acceleration.
By calculating B (GB), the driving torque that can be transmitted to the road surface is estimated from the rotational acceleration B of the driven wheels generated during the acceleration slip of the driving wheels. In other words, the force F that the driving wheels can transmit to the road surface is F = μWF = MBB (WF is the driving force sharing load, = MB is the vehicle mass) in the case of a front-wheel drive vehicle (2). As is clear from the above formula (2), when the driving force sharing load WF and the vehicle mass MB are constant values, the road surface friction coefficient μ and the vehicle body acceleration B are in a proportional relationship. Also,
As shown in FIG. 9, when the drive wheels slip and become larger than “2”, the maximum μ is exceeded, and μ approaches the point “1”. If the slip is settled, "1"
Through the peak of "2" to enter the region of "2" to "3". If the vehicle body acceleration B at “2” can be measured, the maximum torque that can be transmitted to the road surface having the friction coefficient μ can be estimated. This maximum torque is used as the reference Tokru TG.

Then, the vehicle body acceleration B (GB) obtained by the vehicle body acceleration calculating section 47 is passed through a filter 48 to be a vehicle body acceleration GBF. That is, in the state of the "1" position in FIG. 9, in order to quickly shift to the state of the "2" position, the previously obtained GBFn-1 and the currently detected GBn are averaged with the same weighting GBFn = (GBFn- 1 + GBn) / 2, the response is delayed between the “2” position and the “3” position in FIG. 9 and the maximum torque is estimated by an acceleration as close as possible to the acceleration corresponding to the “2” position. In order to estimate a large maximum Tokuru and improve acceleration, GBFn = (27GBFn-1 + 5GBn) / 32 is given by giving weight to GBFn-1 obtained last time. The vehicle body acceleration GBF is calculated by the reference torque calculation unit.
Then, the reference torque TG = GBF × W × Re is calculated. Here, W is the vehicle weight and Re is the tire radius. Then, the reference torque T calculated by the reference torque calculation unit 49
G is sent to the torque lower limit value limiting unit 50, and the lower limit value Ta of the reference torque TG is limited to, for example, 45 Kg · m.

Further, the vehicle body speed VB selected by the high wheel speed selection unit 45 is
Is multiplied by 1.03 in the constant multiplication unit 51, and then the addition unit
At 52, the variable K1 stored in the variable storage unit 53 is added to obtain the reference driving wheel speed VΦ. Here, K1 changes according to the magnitude of the vehicle body acceleration GBF, as shown in FIG. As shown in FIG. 10, when the vehicle body acceleration GBF (B) is large, it is determined that the vehicle is traveling on a bad road such as a jagged road. Since there is a peak of μ, K1 is increased to increase the reference drive wheel speed VΦ that is a reference for slip determination, and the slip determination is weakened to increase the slip ratio to improve the acceleration performance. And the addition unit
The driving wheel speed VF obtained in 52 and the adding section 52
The reference drive wheel speed VΦ, which is the output of, is subtracted in the subtraction unit 54 to calculate the slip amount DV = VF−VΦ.

Next, the slip amount DV is sent to the TSn calculator 55 at a sampling time T of 15 ms, for example, and the slip amount DV is calculated by the coefficient KI.
The correction torque TSn is obtained by integrating while being multiplied by. That is, the correction torque obtained by integrating the slip amount DV with TSn = Kl · ΣDVi, that is, the integral correction torque TSn is obtained. Also,
The coefficient KI changes according to the slip amount DV as shown in FIG.

Further, the slip amount DV is calculated at each sampling time T.
The correction torque TPn proportional to the slip amount DV is sent to the TPn calculation unit 56 to be calculated. That is, the correction torque proportional to the slip amount DV, that is, the proportional correction torque TPn is obtained as TPn = DV × Kp (Kp is a coefficient). This coefficient Kp is the 12th
As shown in the figure, it changes according to the slip amount DV.

The subtraction between the reference torque TΦ and the integral type correction torque TSn calculated by the TSn calculation unit 55 is performed by the subtraction unit 57.
Performed in. As a result of the subtraction, TG-TSn indicates that the lower limit value of torque is Tb, for example, 45 Kg.
Limited to m. Further, in the subtraction unit 59, TG-TSn
-TPn is calculated and set as the target torque TΦ. Based on the target torque TΦ, the engine torque calculation unit 60 calculates “TΦ × 1 / (ρM · ρD · t)” to calculate the target torque TΦ ′ as the engine torque. Here, ρM is a gear ratio, ρD is a reduction ratio, and t is a torque ratio. Then, the target torque TΦ ′ as the engine torque calculated by the engine torque calculation unit 60 has a minimum torque of “0 kg · m” in the minimum torque limiting unit 61.
It is said that That is, only the eye torque TΦ ′ of 0 Kg · m or more is output to the correction unit 63 via the switch 62. The switch 62 is closed or opened when a certain condition is satisfied, and the process of controlling the throttle opening to control the output torque of the engine to the target torque is started or ended. The case where the switch 62 is closed is a case where, for example, the following three conditions (1) to (3) are all satisfied. (1) Idle SW is off.
(2) When the main throttle opening Θm is in the shaded area in FIG. 7. (3) DVFR (FL)> 2, GW> 0.2g, and ΔD
V> 0.2g (where g is gravitational acceleration). Also, switch 6
Case 2 is opened when, for example, any of the following four conditions is satisfied. In other words, (1) The state where the main throttle opening Θm <0.533Θs continues for 0.5 seconds.
(2) The accelerator SW remains on for 0.5 seconds. (3) Idol S
W on continues for 0.5 seconds. (4) ABS operation. In addition, the correction unit 6
In 3, the target torque TΦ 'is corrected according to the water temperature, atmospheric pressure, and intake air temperature.

The target torque TΦ 'is converted into the TΦ'-Θs' conversion unit.
An equivalent throttle opening Θs ′ for obtaining the target torque TΦ ′ when the main throttle valve THm and the sub-throttle valve THs are considered to be one is sent to 64. The TΦ-Θs' relationship is shown in FIG. Above T
The equivalent throttle opening Θs ′ obtained by the Φ′-Θs ′ conversion unit 64 is sent to the Θs′-θs conversion unit 65, and the sub-case when the equivalent throttle opening Θs ′ and the main throttle opening Θm are input. The throttle opening Θs is obtained. The sub-throttle opening Θs is the limiter 66.
Is output to. The limiter 66 gives a lower limit to the sub-throttle opening Θs because if the sub-throttle opening Θs is too small when the engine speed Ne is low, engine stall occurs. The relationship between this lower limit and the engine speed Ne is shown in FIG. As shown in FIG. 14, the lower limit value increases as the engine speed Ne decreases. Then, the sub-throttle valve is controlled so as to have the sub-throttle opening Θs, and the engine output becomes the target torque.

Next, the operation of the vehicle acceleration slip prevention device according to the embodiment of the present invention configured as described above will be described. First, the wheel speeds VFR and VFL of the drive wheels output from the wheel speed sensors 11 and 12 are averaged by the averaging unit 21 to calculate the average wheel speed (VFR + VFL) / 2. At the same time, the wheel speeds VFR and VFL of the drive wheels are set to the low wheel speed selection unit.
Then, the smaller wheel speed of the wheel speed VFR and the wheel speed VFL is selectively output. Furthermore, the average part
The wheel speed output from 21 is multiplied by a variable K in the weighting unit 23, and the wheel speed output from the low wheel speed selecting unit 22 is multiplied by (1-K) in the weighting unit 24, and then added to the adding unit 25. It is sent and added. The variable K is selected from the maximum of KG, KT, and KV shown in FIGS. 3 to 5. This is when turning, the time after the start of brake control,
This is for adapting to various conditions of the vehicle body speed VB. That is, if only the wheel speed output from the low wheel speed selection unit 22 is used, the engine output reduction control is performed according to the lower wheel speed, so only the brake is applied to the wheel with the higher wheel speed, that is, the wheel with the larger slip amount. The engine output is reduced according to the higher wheel speed, that is, the wheel speed with the larger slip amount when only the wheel speed output from the averaging unit 21 is used because the amount of reduction in the engine output that is the control of Since the engine output is greatly reduced and the acceleration of the vehicle is reduced, the weighting units 23 and 24 are provided to change the value of K, and the low wheel speed selection unit 22 and the averaging unit 21 are changed.
The wheel speed output from the vehicle is weighted to prevent the drive wheels from slipping in accordance with the driving state of the vehicle. That is, when the turning tendency of the KG increases (when the centripetal acceleration GY increases), the KG is set to "1" and the average wheel speed of the averaging unit 21 is used. Is prevented from being erroneously determined as slip. In addition, KT sets KT to “1” when the brake control time becomes long, and also uses slip prevention by reducing the engine output to prevent an increase in energy loss due to long-term use of the brake control. In addition, KV is when starting (V
B = 0) has the largest variation in both wheels, and brake control is useful for quick slip prevention.
= 0, but when driving at high speed, KV = 1 and the average part
By using only the average wheel speed of 21, sudden braking due to the use of brakes during slips at high speeds is avoided. The wheel speed output from the adder 25 is sent to the differentiator 26 as the drive wheel speed VF to calculate the temporal speed change of the drive wheel speed VF, that is, the drive wheel acceleration GW, and to drive the wheel as described later. It is used when calculating the slip amount DV of the wheel.

Further, the wheel speed VFR of the right driving wheel detected by the wheel speed sensor 11 is sent to a subtracting section 27 to be subtracted from a reference driving wheel speed VΦ which will be described later and the left side detected by the wheel speed sensor 12. The wheel speed VFL of the driving wheel is subtracted by the subtracting unit 28.
And is subtracted from the reference drive wheel speed VΦ which will be described later. Now, the output of the subtraction unit 27 is multiplied by a (0 <a <1) in the multiplication unit 29, and the output of the subtraction unit 28 is the multiplication unit.
After being multiplied by (1-a) in 30, the addition is performed in the adder 31 to obtain the slip amount DVFR of the right drive wheel. Similarly, the output of the subtractor 28 is multiplied by a in the multiplier 32, and the output of the subtractor 27 is (1-a) in the multiplier 33.
After being multiplied, it is the slip amount DVFL of the left driving wheel that is added in the adding unit 34. For example, when a is set to "0.8", if one drive wheel slips, the other drive wheel is also braked by 20%. This is because if the brakes on the left and right drive wheels are made completely independent, when one drive wheel is braked and rotation is reduced, the drive wheel on the other side will slip due to the action of the diff and the brake will be applied, and this operation is repeated alternately. Is not preferable. The slip amount DVFR of the right driving wheel is differentiated in a differentiating section 35 to calculate its temporal change amount, that is, the slip acceleration GFR, and the slip amount DVFL of the right driving wheel is differentiated in a differentiating section 36 to obtain its time. The dynamic change amount, that is, the slip acceleration GFL is calculated.
Then, the slip acceleration GFR is sent to the brake fluid pressure change amount (ΔP) calculation unit 37, and the GFR (GF) shown in FIG.
L) -ΔP conversion map is referred to and slip acceleration GFR
A change amount ΔP of the brake fluid pressure for suppressing the above is obtained. Similarly, the slip acceleration GFL is sent to the brake fluid pressure change amount (ΔP) calculation unit 38, and G shown in FIG.
By referring to the FR (GFL) -ΔP conversion map, the change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFL is obtained.

Further, a change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFR output from the ΔP calculation unit 37 is a ΔP-T conversion for calculating the opening time T of the inlet valve 17i and the outlet valve 17o via the switch 39. Part 40
To the inlet valve when the change amount ΔP is positive.
The opening time of 17i and the opening time of the outlet valve 17o are respectively calculated when the variation ΔP is negative. Inlet valve calculated in the ΔP-T converter 40
The opening time T of 17i is added to the ineffective liquid amount correction value ΔTR being controlled in the adding section 41 to obtain the braking operation time FR of the right drive wheel. Similarly, the amount of change ΔP of the brake fluid pressure for suppressing the slip acceleration GFL output from the ΔP calculator 38 is changed by the inlet valve via the switch 42.
It is sent to the ΔP-T converter 43 that calculates the opening time T of the 18i and the outlet valve 18o. When the change amount ΔP is positive, the opening time of the inlet valve 18i is changed, and the change amount ΔP is changed.
When is negative, the opening time of the outlet valve 18o is required. The opening time T of the inlet valve 18i calculated in the .DELTA.P-T conversion section 43 is added to the ineffective liquid amount correction value .DELTA.TL under control in the addition section 44 to be the braking operation time FL of the left drive wheel. By correcting the invalid liquid amount correction values ΔTR and ΔTL as described above, the shortage of the liquid amount from when the valve is turned on to when the brake starts to be applied is corrected. In this way, the slip amount of the drive wheels is increased and the switches 39, 42 are increased as described in the configuration.
When the conditions for closing are satisfied, the drive wheels are braked.

Further, the wheel speeds VRR and VRL of the driven wheels detected by the wheel speed sensors 13 and 14 are sent to the high wheel speed selection unit (SH) 45, and the higher wheel speed of the wheel speed VRR and the wheel speed VRL is determined. Is selected and output as the vehicle speed VB. The high wheel speed selection unit 23 prevents the erroneous determination of slip by selecting, as the vehicle body speed VB, the one having a higher wheel speed between the inner wheel and the outer wheel in consideration of the difference between the inner wheels while traveling on a curve. . That is, as will be described later, the vehicle body speed VB serves as a reference speed for detecting the occurrence of slip, and by increasing the vehicle body speed VB,
The erroneous determination of slip occurrence due to the difference in the inner wheels while driving on a curve is prevented.

At the same time, the wheel velocities VRR and VRL of the driven wheels detected by the wheel speed sensors 13 and 14 are sent to the centripetal acceleration G calculation section 46, and GY is the centripetal G for determining the presence or absence of turning and the degree thereof. It is calculated.

Further, the vehicle speed VB selected and output by the high wheel speed selection unit 45 is calculated by the vehicle body acceleration calculation unit 47 as the vehicle speed VB acceleration, that is, the vehicle body acceleration B (GB).

Then, the vehicle body acceleration B (GB) obtained by the vehicle body acceleration calculating section 47 is passed through a filter 48 to be a vehicle body acceleration GBF. In other words, in the state of the "1" position in FIG. 9, in order to quickly shift to the state of the "2" position, GBFn-1 obtained last time and GBn detected this time are averaged with the same weighting, GBFn = ( GBFn-1 + GBn) / 2, the response is delayed between the "2" position and the "3" position in FIG. 9 and the maximum torque is estimated at an acceleration as close as possible to the acceleration corresponding to the "2" position. In order to estimate a larger maximum torque and improve the acceleration performance, the previously calculated GBFn-1 is retained by weighting GBFn-1 obtained last time to GBFn = (27GBFn-1 + 5GBn) / 32. The proportion is increasing.

Then, the vehicle body acceleration GBF is sent to the reference torque calculation unit 49, and the reference torque TG = GBF × W × Re is calculated.
Here, W is the vehicle weight and Re is the tire radius. Then, the reference torque TG calculated by the reference torque calculation unit 49 is sent to the torque lower limit value limiting unit 50, and the lower limit value of the reference torque TG is limited to Ta, for example, 45 Kg · m.

Further, the vehicle body speed VB selected by the high vehicle height selection unit 45 is multiplied by, for example, 1.03 in the constant multiplication unit 51, and then added by the addition unit 52.
In, the variable K1 is added to the variable K1 stored in the variable storage unit 53 to obtain the reference driving wheel speed VΦ. Here, K1 changes according to the magnitude of the vehicle body acceleration GBF, as shown in FIG.
As shown in FIG. 10, when the vehicle body acceleration B is large, it is determined that the vehicle is traveling on a bad road such as a jagged road, and in such a case, K1 is increased to serve as a reference for slip determination. Acceleration is improved by increasing the reference drive wheel speed VΦ and making slip determination less sensitive. Then, the drive wheel speed VF obtained by the adder 52 and the reference drive wheel speed VΦ output from the adder 52 are subtracted by the subtractor 54 to calculate the slip amount DV = VF−VΦ.

Next, the slip amount DV is sent to the TSn calculator 55 at a sampling time T of 15 ms, for example, and the slip amount DV is calculated by the coefficient KI.
The correction torque TSn is obtained by integrating while being multiplied by. That is, the correction torque obtained by integrating the slip amount DV with TSn = KI · ΣDVi, that is, the integral correction torque TSn is obtained. Also,
The coefficient KI changes according to the slip amount DV as shown in FIG.

Further, the slip amount DV is calculated at each sampling time T.
The correction torque TPn proportional to the slip amount DV is sent to the TPn calculation unit 56 to be calculated. That is, the correction torque proportional to the slip amount DV, that is, the proportional correction torque TPn is obtained as TPn = DV × Kp (Kp is a coefficient). This coefficient Kp is the 12th
As shown in the figure, it changes according to the slip amount DV.

That is, as shown in FIGS. 11 and 12, the coefficients KI and Kp are DV
It is small when> 0. This corresponds to DV> 0 in a region larger than VΦ in FIG. 8, but since the range of DV fluctuation is wide in this region, increasing the coefficients KI and Kp will increase the slip amount.
This is because the gain becomes large and the control becomes unstable by increasing the coefficients KI and Kp although the change of DV is large. When DV <0 (that is, the shaded area in FIG. 8)
In this case, the coefficients KI and Kp are increased to increase the gain.
This is small when DV <0 because the fluctuation range is only between VΦ and VB as shown in FIG. 8, so the coefficients KI, K
The response is improved by increasing p by increasing the gain. Further, as shown in FIG. 15, when the centripetal acceleration GY increases, that is, when the turning tendency increases, ΔKp (FIG. 12) is increased to increase the value of Kp when DV> 0 and control becomes unstable. The gain is increased to the extent that it does not occur, the occurrence of slip on the curve is suppressed, and the turning performance is improved.

Then, the integral type correction torque TSn calculated by the TSn calculation unit 55 is subtracted from the reference torque TΦ by the subtraction unit 57. As a result of the subtraction, in the torque lower limit value unit 58, the lower limit value of torque of TG-TSn is limited to Tb, for example, 45 Kg · m. Further, in the subtraction unit 59, TG-TSn-TP
n is calculated and set as the target torque TΦ. Based on this target torque TΦ, in the engine torque calculation unit 60,
“TΦ × 1 / (ρM · ρD · t)” is calculated, and the target torque TΦ ′ as the engine torque is calculated. Here, ρM is a gear ratio, ρD is a reduction ratio, and t is a torque ratio. Then, only the target torque TΦ ′ of 0 Kg · m or more is output to the correction unit 63 via the switch 62.
In this correction unit 63, the target torque TΦ 'is corrected according to the water temperature, atmospheric pressure, and intake air temperature.

The target torque TΦ 'is converted into the TΦ'-Θs' conversion unit.
In step S64, the equivalent throttle opening Θs ′ is calculated according to the target torque TΦ ′ when the two throttles of the main throttle valve THm and the sub throttle valve THs are considered to be one. The TΦ'-Θs' relationship is shown in FIG. The equivalent throttle opening Θs ′ obtained by the TΦ′-Θs ′ conversion unit 64 is sent to the Θs′-Θs conversion unit 65, and the equivalent throttle opening Θs ′ and the main throttle opening Θm are input. The sub-throttle opening Θs is obtained. Then, this sub-throttle opening Θs is output to the limiter 66. If the sub-throttle opening Θs is too small, the limiter 66 causes an engine stall when the engine speed Ne is low, so the lower limit is given to the sub-throttle opening Θs. Then, the sub-throttle valve is controlled so as to have the sub-throttle opening Θs, and the engine output torque is set to the maximum torque that can be transmitted in the current road surface state.

When only one throttle valve is used without using two throttle valves as in the present embodiment, the equivalent throttle opening Θs ′ becomes the opening of the throttle valve as it is.

[Advantages of the Invention] As described in detail above, according to the present invention, when slip is suppressed, the coefficient Kp for calculating the proportional correction torque is increased to increase the gain and improve the responsiveness. It is possible to provide an acceleration slip prevention device for a vehicle.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle acceleration slip prevention device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing control of the traction controller of FIG. 1 for each functional block, FIG. 3 shows the relationship between the centripetal acceleration GY and the variable KG, FIG. 4 shows the relationship between the time after the start of control and the variable KT, and FIG. 5 shows the relationship between the vehicle body acceleration B and the variable KV. FIG. 6 is a diagram showing the relationship between the slip acceleration GFR (GFL) and the brake fluid pressure change ΔP, and FIG. 7 is a diagram showing the relationship between the engine speed Ne and the main throttle opening Θm. The figure shows the relationship between time t and the drive wheel speed VF, the reference drive wheel speed VΦ, and the vehicle body speed VB. FIG. 9 shows the relationship between the slip ratio and the road surface friction coefficient μ. FIG. 10 shows the vehicle body acceleration GBF. And FIG. 11 is a diagram showing the relationship between the slip amount DV and the coefficient KI, FIG. The slip amount D
FIG. 13 shows the relationship between V and the coefficient KP. FIG. 13 shows the target torque T.
A diagram showing the relationship between Φ ′ and the equivalent throttle opening Θs ′,
FIG. 14 shows the relationship between the engine speed Ne and the lower limit value of the sub-throttle opening Θs, FIG. 15 shows the relationship between the centripetal acceleration GY and ΔKp, and FIG. 16 shows the throttle valves THm, THs. It is a figure. 11-14 Wheel speed sensor, 15 Traction controller, 16 Engine, 21 Average section, 22 Low vehicle height selection section, 23,24 Weighting section, 37,38 ΔP calculation Department,
46 ... centripetal G calculation unit, 55 ... TSn calculation unit, 56 ... TPn calculation unit, 65 ... Θm-Θs conversion unit.

Claims (1)

[Claims] 1. A driving wheel speed detecting means for detecting a driving wheel speed VF, a driven wheel speed detecting means for detecting a driven wheel speed VB, a torque reducing means for reducing a driving torque, the driving wheel speed VF and the above. The slip amount DV is calculated according to the difference from the driven wheel speed VB, and when at least the slip amount DV is larger than a predetermined value, first means for starting the reduction of the drive torque by the torque reducing means, and the slip The correction torque TP calculated by multiplying the amount DV by the coefficient Kp and the correction torque TS by the integration of the slip amount DV (KiΣDV, Ki is a coefficient)
And the reference torque TG from the acceleration of the driven wheel speed VB
Then, the target torque TΦ = TG−KiΣDV−KpDV is set, and at least when the slip amount DV is larger than the set value, the engine output is controlled so as to reach the target torque TΦ, and the drive control for recovering the driving force torque is performed. Means for preventing acceleration slippage of a vehicle, wherein the coefficient Kp is smaller in the case of DV> 0 than in the case of DV <0.