JP2629910B2 - Anti-slip device for vehicles - Google Patents

Description

Description of the Invention (Object of the Invention) (Industrial application field) The present invention relates to a device for preventing acceleration slip of a vehicle.

2. Description of the Related Art Conventionally, there has been known an acceleration slip prevention device (traction control device) for preventing a drive wheel from slipping when a vehicle is rapidly accelerated. In such a traction control device, when the acceleration slip of the drive wheel is detected, the slip ratio S is controlled so that the friction coefficient μ between the tire and the road falls within the maximum range (the hatched range in FIG. 18). Here, the slip ratio S is [(VF−VB)
/ VF] × 100 (percent), VF is the wheel speed of the drive wheel, and VB is the vehicle speed. That is, when the slip of the drive wheel is detected, the vehicle speed speed VF of the drive wheel is controlled so as to control the engine output so that the slip ratio S falls within the hatched range, and the friction coefficient μ between the tire and the road surface is increased. Is controlled to fall within the maximum range, thereby preventing the slip of the drive wheels during acceleration and improving the acceleration performance of the vehicle.

(Problems to be Solved by the Invention) In such a traction control device, if the start condition of the slip control is not appropriate, the engine output is controlled even with a small acceleration slip, the acceleration performance is reduced, or the large acceleration slip is reduced. However, problems such as the engine output not being controlled immediately occur.

Therefore, conventionally, a traction control device that starts slip control when any of the control start determination data of the wheel speed VF of the drive wheel, the slip ratio S, or the slip change rate ΔS becomes equal to or greater than a predetermined threshold has been considered. However, since the wheel speed VF, the slip ratio S, and the slip change ratio ΔS are all obtained based on the sensor data of the driving wheel speed sensor, when an abnormality occurs in the driving wheel speed sensor, the normal control start determination data is not obtained. Otherwise, the start of the slip control becomes unstable.

The present invention has been made in view of the above points, and an object of the present invention is to provide an acceleration slip prevention device for a vehicle that can start slip control at an appropriate timing at all times.

[Structure of the Invention] (Means and Actions for Solving the Problems) That is, the vehicle acceleration slip prevention device according to the present invention is a drive wheel slip amount detection unit that detects a slip amount generated in a drive wheel based on a drive wheel speed. And a plurality of types of different driving information detected by different driving information detecting means, and at least two driving information detected by the driving information detecting means are independently determined in advance by a determination condition. Control start determining means for starting drive torque control according to the slip amount detected by the drive wheel slip amount detecting means when the control start condition is satisfied. The driving means includes a driving torque detecting means for detecting a driving torque of the engine. Has been the driving torque of the engine, the maximum torque over the road surface friction coefficient is not slipping occurs at ultra-low μ road is not zero, is intended to include.

(Embodiment) Hereinafter, an acceleration slip prevention device for a vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a configuration diagram showing an acceleration slip prevention device for a vehicle. The figure shows a front wheel drive vehicle, WFR is a front right wheel, WFL is a front left wheel, WRR is a rear right wheel,
WRL indicates a rear left wheel. Reference numeral 11 denotes a wheel speed sensor for detecting the vehicle speed VFR of the front right wheel (drive wheel) WFR. Reference numeral 12 denotes the wheel speed V of the front left wheel (drive wheel) WFL.
A wheel speed sensor 13 for detecting the FL, a wheel speed sensor 13 for detecting the wheel speed VRR of the rear right wheel (driven wheel) WRR, 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 sends a control signal to the engine 16 to perform control to prevent slippage of the drive wheels during acceleration.

FIG. 1 (B) shows an intake system of the engine 16, in which 21 is an air cleaner, 22 is an intake pipe, and the intake pipe 22 is mainly operated by an accelerator pedal. In addition to the throttle valve THm23, an auxiliary throttle valve THs24 whose opening is controlled by a control signal θs from the traction controller 15 is provided.
That is, the intake air introduced through the air cleaner 21 flows to the intake valve side through the auxiliary throttle valve THs24 and the main throttle valve THm23 in series, and the opening degree of the auxiliary throttle valve THs24 is determined by the traction controller 15 from the traction controller 15. The motor drive circuit 25 and its motor 24
The driving force of the control engine 16 is controlled via M. Here, the opening degrees of the main throttle valve THm23 and the sub throttle valve THs24 are detected by the main throttle position sensor 26 and the sub throttle position sensor 27, respectively. The main throttle valve THm23 is provided with a main throttle idle SW28 for detecting a non-depressed state of the accelerator pedal, and the sub throttle valve THs24 is provided with a sub throttle fully open SW29. Further, an air flow sensor 30 for detecting an intake air amount is provided downstream of the air cleaner 21, and output signals from these sensors 26, 27, 30 and SWs 28, 29 are:
Either is given to the traction controller 15.

On the other hand, in FIG. 1 (A), reference numeral 17 denotes a front right wheel WFR.
Wheel cylinder for braking, 18 is the front left wheel W
A wheel cylinder that brakes the FL. These wheel cylinders usually have a brake pedal (not shown)
By operating, pressure oil is supplied via a master cylinder or the like (not shown). At the time of traction control operation, pressure oil can be supplied from another path described below. Supply of pressure oil from the hydraulic pressure source 19 to the wheel cylinder 17 is performed via an inlet valve 17i, and discharge of pressure oil from the wheel cylinder 17 to the reservoir 20 is performed via an outlet valve 17o. The supply of pressure oil from the hydraulic pressure source 19 to the wheel cylinder 18 is performed via an inlet valve 18i, and the discharge of pressure oil from the wheel cylinder 18 to the reservoir 20 is performed via an outlet valve 18o. The opening and closing control of the inlet valves 17i and 18i and the outlet valves 17o and 18o is performed by the traction controller 15.

Here, the driving force control of the engine 16 and the driving wheel WFR
The slip prevention control by the brake control of the WFL 12 is started / terminated by a combination of independent control start determination conditions based on signals from various sensors detecting a plurality of different operating states.

Next, a detailed configuration of the traction controller 15 will be described with reference to FIG. Wheel speed sensor 11
The wheel speeds VFR and VFR of the drive wheels detected in
The FL is sent to a high vehicle speed selecting section (SH) 31, and a higher wheel speed is selected and output from the wheel speed VFR and the wheel speed VFL. At the same time, the wheel speeds VFR and VFL of the drive wheels detected by the vehicle speed sensors 11 and 12 are averaged in an averaging unit 32 to calculate an average wheel speed (VFR + VFL) / 2. The wheel speed output from the high vehicle speed selection unit 31 is multiplied by a variable KG in a weighting unit 33, and the average wheel speed output from the averaging unit 32 is multiplied by a variable (1-KG) in a weighting unit 34, and each is added. It is sent to the section 35 and added to make the driving wheel speed VF. The variable KG is a variable that changes according to the centripetal acceleration GY as shown in FIG. As shown in FIG. 3, the centripetal acceleration GY is set so as to be proportional to the centripetal acceleration up to a predetermined value (for example, 0.1 g), and to become "1" when it exceeds the centripetal acceleration.

The wheel speeds of the driven wheels detected by the wheel speed sensors 13 and 14 are input to the low vehicle speed selection unit 36, and the smaller wheel speed is selected. Further, the wheel speed sensor 1
The wheel speeds of the driven wheels detected in 3 and 14 are input to the high vehicle speed selection unit 37, and the larger wheel speed is selected. Then, the smaller wheel speed selected by the low vehicle speed selector 36 is multiplied by the variable Kr in the weighting unit 38, and the larger wheel speed selected by the high vehicle speed selector 37 is weighted by the weighting unit 39.
Is multiplied by the variable (1-Kr). This variable Kr is the fourth
As shown in the figure, it changes between “1” and “0” according to the centripetal acceleration GY.

Further, the wheel speeds output from the weighting unit 38 and the weighting unit 39 are used as a driven wheel speed VR added by the adding unit 40, and the driven wheel speed VR is further multiplied by the multiplying unit 4.
At 0 ', the target drive wheel speed Vφ is multiplied by (1 + α).

The drive wheel speed VF output from the adder 35
And the target driving wheel speed Vφ output from the multiplication unit 40 'is subtracted by the subtraction unit 41 to obtain the slip amount DVi' (= VF-
Vφ) is calculated. The slip amount DVi 'is further corrected in the adder 42 in accordance with the centripetal acceleration GY and the rate of change GY of the centripetal acceleration ΔGY. That is, a slip correction amount Vg that changes according to the centripetal acceleration GY as shown in FIG. 5 is set in the slip amount correction unit 43, and a centripetal acceleration as shown in FIG. A slip correction amount Vd that changes according to the change rate ΔGY of GY is set. Then, the addition unit 42 adds the slip correction amounts Vd and Vg to the slip amount DVi 'output from the subtraction unit 41 to obtain the slip amount DVi.

The slip amount DVi is sent to the calculation unit 45a in the TSn calculation unit 45 at a sampling time T of, for example, 15 ms, and
DVi is integrated while being multiplied by the coefficient KI to obtain the correction torque TS
n 'is required. In other words, a correction torque obtained by correcting the slip amount DVi, that is, an integral correction torque TSn 'is obtained as TSn' = ΣKI · DVi (KI is a coefficient that changes in accordance with the slip amount DVi). The integral type correction torque TSn 'is applied to the drive wheels WFR and WFL.
Correction value for the torque for driving the engine 16
It is necessary to adjust the control gain in accordance with the change in the characteristic of the power transmission mechanism between the power transmission mechanism and the drive wheels due to the switching of the shift speed. Then, the corrected integrated correction torque TSn corresponding to the gear position is calculated.

In addition, the slip amount DVi is calculated by T
The correction torque TPn ′ is sent to the calculation section 46a of the Pn calculation section 46 and corrected by the slip amount DVi to be calculated. In other words, TPn ′ = DVi · Kp (Kp is a coefficient) and the corrected torque corrected by the slip amount DVi,
That is, the proportional correction torque TPn 'is obtained. And
The proportional-type correction torque TPn 'is multiplied by a different count GKp depending on the speed in the coefficient multiplying unit 46b for the same reason as the integral-type correction torque Sn', and the corrected proportional-type correction torque TPn corresponding to the speed is calculated. Is done. You.

Further, the driven wheel speed VR output from the adder 40 is input to the reference torque calculator 47 as the vehicle speed VB.
Then, the vehicle acceleration calculation section in the reference torque calculation section 47
At 47a, the acceleration VB (GB) of the vehicle speed is calculated.

Then, the vehicle body acceleration B (GB) calculated by the vehicle body acceleration calculating section 47a is passed through a filter 47b to become the vehicle body acceleration GBF. In the filter 47b, the fifteenth filter
In order to quickly shift to the state of the position “2” when the acceleration is increased in the state of the position “1” in FIG.
The average of the output of G BFn- ₁ and the currently detected G BFn is given by the following equation: G BFn = GBn + GBFn− ₁ ) / 2 (1) Also, when the acceleration is reduced with the slip ratio S> S1 (S1 is set to a value slightly smaller than the maximum slip ratio Smax), for example, when the position shifts from the “2” position to the “3” position, To be shifted, filter 47b is switched to a slower filter. That is, the weight of the output of the previous filter 47b is given as GBFn = GBn + 7GBFn- ₁ ) / 8 (2).

When the acceleration is reduced with the slip ratio S ≦ S1, that is, when the acceleration is reduced in the region of “1”, Sm is as small as possible.
To want to stay at ax, filter 47b is switched to a slower filter. In other words, the weight of the previous output of the filter 47b is very high as GBFn = GBn + 15GBFn- ₁ ) / 16 (3). As described above, in the filter 47b, the filter 47b is switched in three stages as shown in the above equations (1) to (3) according to the state of the acceleration. Then, the vehicle body acceleration GBF is sent to the reference torque calculation unit 47c, and the reference torque TG is calculated. That is, TG = GBF × W × Re is calculated. Here, W is the vehicle weight, and Re is the tire radius.

The reference torque TG and the integral correction torque T
Subtraction with Sn is performed in a subtractor 48, and further subtraction with the proportional correction torque TPn is further performed in a subtractor 49. Thus, the target torque Tφ is calculated as Tφ = TG−TSn−TPn.

Since the target torque Tφ indicates the torque for driving the drive wheels WFR and WFL, the target torque Tφ is divided by the total gear ratio between the engine 16 and the drive wheels in the engine torque calculation unit 50 and converted into the target engine torque Tφ ′. . And
The target engine torque Tφ 'is the lower limit value Tl of the engine torque.
In the lower limit value setting section 51 which sets im, the target engine torque Tφ is obtained by the lower limit value Tlim which changes according to the temperature t elapsed from the start of the traction control or the vehicle speed VB as shown in FIG. 16 or FIG. Is limited. Then, the target engine torque T for which the lower limit value of the engine torque is set by the lower limit value setting unit 51.
φ 'is sent to the torque / throttle opening degree converter 52, and the opening degree θs of the auxiliary throttle valve for generating the target engine torque Tφ' is obtained. Then, by adjusting the opening degree θs of the auxiliary throttle valve, the output torque of the engine is controlled so as to become the target engine torque Tφ ′.

The wheel speeds VRR and VRL of the driven wheels are calculated by a centripetal acceleration calculation unit.
Sent to 53 to determine the degree of turning, the centripetal acceleration G
Y 'is required. The centripetal acceleration GY 'is sent to the centripetal acceleration correction unit 54, and the centripetal acceleration GY' is corrected according to the vehicle speed.

That is, GY = Kv · GY ′, and the coefficient Kv changes according to the vehicle speed as shown in FIGS. 7 to 12, whereby the centripetal acceleration GY is corrected according to the vehicle speed.

By the way, the subtraction unit 55 subtracts from the wheel speed VFR of the driven wheel the wheel speed of the driven wheel output from the high vehicle speed selection unit 37 which has the higher vehicle speed. Further, the subtraction unit 56 subtracts the wheel speed of the driven wheel output from the high vehicle speed selection unit 37 which has the higher vehicle speed from the wheel speed VFL of the drive wheel.

The output of the subtraction unit 55 is multiplied by KB (0 <
KB <1), the output of the subtraction unit 56 is multiplied by (1−KB) in the multiplication unit 58, and then added in the addition unit 59 to obtain the slip amount DVFL of the right driving wheel. At the same time,
The output of the subtraction unit 56 is multiplied by KB in the multiplication unit 60, and the output of the subtraction unit 55 is multiplied by (1-KB) in the multiplication unit 61 and then added in the addition unit 62 to obtain the slip amount DVFR of the left driving wheel. It is said. The variable KB changes according to the elapsed time from the start of the traction control as shown in FIG. 13, and is set to "0.5" at the start of the traction control, and becomes "0.8" as the traction control is advanced. ". For example, when KB is set to “0.8”, brake control is performed by confirming that slippage has occurred in only one drive wheel by 20% of one drive wheel when the other drive wheel has slippage. I have to. This is because if the brakes on the left and right drive wheels are completely independent, if only one of the drive wheels is braked and the rotation decreases, the differential drive wheel will slip and the brake will be applied this time due to the action of the differential. This is because it is not preferable to be repeated. The slip amount DVFR of the right driving wheel is calculated by the differentiator 63.
And the temporal change amount, that is, the slip acceleration GFR is calculated, and the slip amount DVFL of the left driving wheel is differentiated in the differentiating section 64 to calculate the temporal change amount, that is, the slip acceleration GFL. . The slip acceleration GFR is calculated based on the amount of change in brake fluid pressure (Δ
P) It is sent to the calculation unit 65, and the GFR (GFL)-
The change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFR is obtained with reference to the ΔP conversion map.
The amount of change ΔP of the brake fluid pressure is sent to the ΔP-T converter 67 to calculate the opening time T of the inlet valve 17i in FIG. 1 (A). Similarly, the slip acceleration GFL is sent to the brake fluid pressure change amount (ΔP) calculation section 66, and the GFR (GFL) -ΔP conversion map shown in FIG. 14 is referred to to suppress the slip acceleration GFL. A change amount ΔP of the brake fluid pressure is obtained. The change amount ΔP of the brake fluid pressure is sent to the ΔP-T conversion unit 68, and the opening time T of the inleo valve 18i in FIG. 1A is calculated.

In FIG. 14, when the brake is applied at the time of turning, in order to strengthen the brake of the drive wheel on the inner wheel side,
The inner wheel side at the time of turning is shown by a broken line a.

On the other hand, a switch S1 is interposed between the subtractor 49 for calculating the target torque Tφ and the engine torque calculating section 50, and the brake hydraulic pressure change amount (ΔP) calculating sections 65 and 66 are converted to a ΔP-T converting section. Between 67 and 68, switch S2
a, S2b are interposed. The switches S1, S2a, S2b are closed / opened when slip control start / end conditions described later are satisfied, respectively.
S2b is controlled to be opened and closed by the control start / end determination unit 69. The control start / end determination unit 69 is supplied with a slip determination signal from the slip determination unit 70. The slip judging section 70 calculates the slip amount DV obtained by the adding section 42.
It is determined whether or not i exceeds a slip determination value α previously stored in the slip determination value storage unit 71 (in this case, α is determined by a map according to road surface conditions). The start / end determination unit 69 is provided. In addition, the control start / end determination unit 69 includes the first
In FIG. 8B, an on / off signal from the main throttle idle SW 28 and a main throttle opening detection signal from the main throttle position sensor 26, a torque detection signal from the engine torque sensor 72, and a shift lever position
A position detection signal from SW73 is provided.

Here, the control start / end determination unit 69 determines whether a slip determination signal (DVi> α) is obtained from the slip determination unit 70 or the torque detected by the engine torque sensor 72 is a predetermined torque value (for example, 4 kg / m: more than 4 kg / m). The maximum throttle value at which no slip occurs on a low μ road), the temporal change rate of the main throttle opening obtained by the main throttle position sensor 26, that is, the load operation speed of the accelerator pedal is a plus predetermined value or more, or the main throttle idle SW 28 Is turned off or when any three of the four control start conditions are satisfied, a control start signal is output, and the switches S1, S2a, and S2b are closed. The control start / end determination unit 69 determines whether a slip determination signal (DVi ≦ α) is obtained from the slip determination unit 70 or the torque detected by the engine torque sensor 72 is a predetermined torque value (for example, 4 kg / m: ultra-low μ). Is less than the maximum torque value at which no slip occurs on the road), the temporal change rate of the main throttle opening obtained by the main throttle position sensor 26, that is, the load operation speed of the accelerator pedal is a minus predetermined value or more, or the main throttle idle SW 28 is on. Did you
When any three of the four control end conditions are satisfied, a control end signal is output, and the switches S1, S2a, and S2b are opened.

Next, the operation of the acceleration slip prevention device for a vehicle according to the embodiment of the present invention configured as described above will be described. 1 and 2, the wheel speed sensors 13, 14
The wheel speeds of the driven wheels (rear wheels) output from are input to a high vehicle speed selection unit 36, a low vehicle speed selection unit 37, and a centripetal acceleration calculation unit 53. In the low vehicle speed selection unit 36, the smaller wheel speed of the left and right wheels of the driven wheels is selected, and the high vehicle speed selection unit 37
In, the larger one of the left and right driven wheels is selected. During normal straight running, if the wheel speeds of the left and right driven wheels are the same, the low vehicle speed selection unit 36
The same wheel speed is selected from the high vehicle speed selection unit 37.
Further, the wheel speeds of the left and right driven wheels are input to the centripetal acceleration calculation unit 53, and the turning degree when the vehicle is turning, that is, how steep the vehicle turns, is determined from the wheel speeds of the left and right driven wheels. Is calculated.

Hereinafter, how the centripetal acceleration is calculated in the centripetal acceleration calculation unit 53 will be described. In a front-wheel drive vehicle, since the rear wheels are driven wheels, the vehicle speed at that position can be detected by a wheel speed sensor regardless of slippage due to driving, so that Ackerman geometry can be used. That is, in the normal turning is calculated as centripetal acceleration GY 'is ^{GY' = v 2 / r ...} (4) (v = vehicle speed, r = radius of gyration).

For example, when the vehicle is turning to the right as shown in FIG. 19, the center of turning is Mo, the distance from the center of turning Mo to the inner wheel side (WRR) is r1, the tread is Δr, and the inner wheel is The wheel speed on the side (WRR) is set to v1, and the outer wheel side (WR
If the wheel speed of L) is v2, v2 / v1 = (Δr + r1) / r1 (5)

Then, the above equation (5) is modified to obtain 1 / r1 = (v2 / v1) / Δr · v1 (6). When the inner ring side is used as a reference, the centripetal acceleration G
Y 'is GY' is calculated as ^{= v1 2 / r = v1 2} · (v2-v1) / Δr · v1 = v1 · (v2 / v1) / Δr ... (7).

That is, the centripetal acceleration GY 'is calculated by the seventh equation.
By the way, since the inner wheel speed v1 is lower than the outer wheel speed v2 during turning, the centripetal acceleration GY 'is calculated using the inner wheel speed v1. Is done. Therefore, the count KG multiplied by the weighting unit 33 is underestimated because the centripetal acceleration GY 'is underestimated. Therefore, the driving wheel speed VF
Is estimated to be small, the slip amount DVi '(VF-
Vφ) is also underestimated. Thus, since the target torque Tφ is largely estimated, the target engine torque is largely estimated, so that a sufficient driving force is applied even during turning.

By the way, in the case of extremely low speed, as shown in FIG. 19, the distance from the inner wheel side to the turning center M0 is r1,
In a vehicle that understeers as the speed increases, the center of turning shifts to M, and the distance is r (r> r1).
It has become. Even when the speed increases in this way, since the turning radius is calculated as r1, the centripetal acceleration GY 'calculated based on the above equation (7) is calculated as a value larger than the actual value. For this reason, the centripetal acceleration GY ′ calculated by the centripetal acceleration calculation unit 53 is sent to the centripetal acceleration correction unit 54, and the coefficient Kv of FIG. 7 is added to the centripetal acceleration GY ′ so that the centripetal acceleration GY becomes small at high speed. Multiplied. This variable
Kv is set so as to decrease according to the vehicle speed, and may be set as shown in FIG. 8 or FIG. Thus, the centripetal acceleration GY corrected by the centripetal acceleration correction unit 54 is output.

On the other hand, as the speed increases, oversteer (r
<R1) In the vehicle, the centripetal acceleration correction unit 54 performs a correction completely opposite to that of the understeer vehicle described above. That is, any one of the variables Kv in FIGS.
Is used to correct the centripetal acceleration GY ′ calculated by the centripetal acceleration calculation unit 53 so as to increase as the vehicle speed increases.

By the way, the smaller wheel speed selected by the low vehicle speed selector 36 is multiplied by a variable Kr in the weighting unit 38 as shown in FIG. 4, and the high vehicle speed selected by the high vehicle speed selector 37 is weighted by the weighting unit 39. Is multiplied by the variable (1-Kr). The variable Kr is set to “1” at the time of turning such that the centripetal acceleration GY becomes larger than 0.9 g, for example.
Is set to “0” when becomes smaller than 0.4 g.

Therefore, for a turn in which the centripetal acceleration GY is greater than 0.9 G, the low vehicle speed wheel speed of the driven wheels output from the low vehicle speed selection unit 36, that is, the inner wheel speed at the time of selection is selected. You. Then, the weighting unit 38 and
The wheel speed output from 39 is added in an adder 40 to obtain a driven wheel speed VR, and the driven wheel speed VR is further multiplied by (1 + α) in a multiplier 40 ′ to obtain a target drive wheel speed V.
φ.

After the higher wheel speed of the drive wheel speeds is selected by the high vehicle speed selection unit 31, the weighting unit 33 multiplies it by the variable KG as shown in FIG. further,
The average vehicle speed of the drive wheels (VFR +
(VFL) / 2 is multiplied by (1−KG) in the weighting section 34, and is added to the output of the weighting section 33 in the adding section 35 to obtain the drive wheel speed VF. Therefore, if the centripetal acceleration GY is, for example, 0.1 g or more, KG = 1, so that the wheel speed of the larger one of the two drive wheels output from the high vehicle speed selection unit 31 is output. Become. That is,
The turning degree of the vehicle increases and the centripetal acceleration GY is, for example, 0.
When the weight is 9 g or more, "KG = Kr = 1", so that the driving wheel side uses the wheel speed of the outer wheel having a higher wheel speed as the driving wheel speed VF, and the driven wheel side uses the wheel speed of the inner wheel having a lower wheel speed. Is set as the driven wheel speed VR, the slip amount DVi ′ (= VF−Vφ) calculated by the subtraction unit 41 is also largely estimated. Therefore, in order to estimate the target torque Tφ to be small, the output of the engine is reduced, the slip ratio S is reduced, and the lateral force A can be increased as shown in FIG. And a safe turn can be performed.

The slip amount DVi 'is added to the slip amount corrector 43 only at the time of turning when the centripetal acceleration GY occurs, as shown in FIG. 5, and the slip amount corrector 44 shown in FIG. Such a slip amount Vd is added. For example, assuming a curve turning at a right angle, the centripetal acceleration GY and its temporal change rate ΔGY have positive values in the first half of the turn, but the temporal change rate of the centripetal acceleration GY in the second half of the curve. ΔGY is a negative value. Accordingly, in the first half of the curve, the adder 42 adds the slip correction amount Vg shown in FIG.
(> 0) and the slip correction amount Vd (> 0) shown in FIG. 6 are added to obtain the slip amount DVi. In the latter half of the curve, the slip correction amount Vg (> 0) and the slip correction amount Vd
(> 0) is added to the slip amount DVi. Therefore, the slip amount DVi in the latter half of the turn is estimated to be smaller than the slip amount DVi in the first half of the turn, thereby reducing the engine output and increasing the lateral force in the first half of the turn, and in the latter half of the turn, The engine output is restored to improve the acceleration of the vehicle.

In this way, the corrected slip amount DVi is, for example, 1
It is sent to the TSn operation unit 45 with a sampling time T of 5 ms. In the TSn calculation unit 45, the slip amount DVi is integrated while being multiplied by the coefficient KI to obtain a correction torque TSn.
That is, a correction torque obtained by correcting the slip amount DVi, that is, an integral correction torque TSn is obtained as TSn = GKiΣKI · DVi (KI is a coefficient that changes in accordance with the slip amount DVi).

At the time of sampling T, the slip amount DVi is sent to the TPn calculator 46, and is sent to the correction torque TPn calculator 46 to calculate the correction torque TPn. That is, a correction torque corrected by the slip amount DVi, that is, a proportional correction torque TPn is obtained as TPn = GKpDVi · Kp (KpHA coefficient).

Further, the values of the coefficients GKi, GKp used in the calculations in the coefficient multiplying units 45b, 46b are switched to values according to the gear position after the shift after a set time from the start of the shift when upshifting. This takes time from the start of the shift to the end of the shift after the shift stage is actually switched, and when shifting up, the above-mentioned coefficients GKi and GK corresponding to the high speed stage after the shift and the shift start
When p is used, the values of the correction torques TSn and TPn are values corresponding to the above-mentioned high speed steps, so that the actual torque is not completed, but becomes smaller than the value before the shift is started, and the target torque φ is increased. This is because the slip is induced and the control becomes unstable.

Further, the driven wheel speed VR output from the adder 40 is input to the reference torque calculator 47 as the vehicle speed VB.
Then, the vehicle body acceleration calculation section 47a calculates the vehicle body speed acceleration B (GB). The acceleration GB of the vehicle speed calculated by the vehicle acceleration calculation section 47a is calculated by the filter 47b as described in (1).
Any one of the filters of the equations (3) to (3) is applied so that GBF is kept at an optimum position according to the state of the acceleration GB. Then, the reference torque calculating section 47c calculates a reference torque TG (= GBF × W × Re).

The reference torque TG and the integral correction torque T
Subtraction with Sn is performed in a subtraction unit 48, and the proportional correction torque TPn is further performed in a subtraction unit 49. Thus, the target torque Tφ is calculated as Tφ = TG−TSn−TPn.

This target torque Tφ is obtained when the switch S1 is closed.
That is, when the control start / end determination section 69 determines that the control start condition is satisfied, the control start / end determination section 69 gives the control torque to the engine torque calculation section 50 and converts it into the target engine torque Tφ ′. The target engine torque Tφ ′ is set in the lower limit value setting section 51 which sets the lower limit value Tlim of the engine torque, as shown in FIG. 16 or FIG. 17, the elapsed time t from the start of the traction control or the vehicle speed VB. Lower limit value Tlim that changes according to
As a result, the lower limit value of the target engine torque Tφ ′ is limited. That is, even when the reference torque TG cannot be detected well, such as at the start of the traction control control or at a low speed, the torque lower limit value Tlim is set slightly larger as shown in FIG. 16 or FIG. It is possible to output an engine torque Tφ ′ that is equal to or greater than the torque at which no slip occurs, thereby obtaining good acceleration.
This is because an engine torque Tφ ′ that is equal to or greater than the torque at which no slip occurs is output, and even when a slip occurs, the occurrence of slip is suppressed by brake control.

The target engine torque Tφ ′ for which the lower limit value of the engine torque is set by the lower limit value setting unit 51 is sent to the torque / throttle opening degree conversion unit 52, and an auxiliary throttle valve for generating the target engine torque Tφ ′ is provided. Of opening θ
s is required. Then, the opening degree θs of the sub throttle valve THs24 of the intake system in FIG.
By adjusting the output torque via the motor 24M, the output torque of the engine 16 is controlled so as to reach the target engine torque Tφ ′, and the maximum driving force that can be transmitted under the current road surface condition is generated.

By the way, the subtraction unit 55 subtracts from the wheel speed VFR of the driven wheel the wheel speed of the driven wheel output from the high vehicle speed selection unit 37 which has the higher vehicle speed. Further, the subtraction unit 56 subtracts the wheel speed of the driven wheel output from the high vehicle speed selection unit 37 which has the higher vehicle speed from the wheel speed VFL of the drive wheel. Therefore, the outputs of the subtraction units 55 and 56 are underestimated to reduce the number of times the brake is used even during turning, and reduce the slip of the drive wheels by reducing the engine torque.

The output of the subtraction unit 55 is KB times (0 <
KB <1), the output of the subtractor 56 is multiplied by (1−KB) in the multiplier 58, and then added in the adder 59 to obtain the slip amount DVFR of the right driving wheel. At the same time,
The output of the subtraction unit 56 is multiplied by KB in the multiplication unit 60, the output of the subtraction unit 55 is multiplied by (1−KB) in the multiplication unit 61 and then added in the addition unit 62 to obtain the slip amount DVFL of the left driving wheel. It is said. The variable KB changes in accordance with the elapsed time t from the start of the traction control as shown in FIG. 13, and is set to “0.5” at the start of the traction control. 0.8 ". That is, when the slip of the drive wheels is reduced by the brake, at the start of braking, both the wheels are simultaneously braked, so that an unpleasant steering wheel shock at the start of braking on a split road, for example, can be reduced. . On the other hand, an operation in the case where the brake control is continuously performed and the KB becomes “0.8” will be described. In this case, when one of the drive wheels slips, the other drive wheel recognizes that the slip has occurred by 20% of the one drive wheel and performs the brake control. This is because if the left and right drive wheels are completely independent of each other, if only one drive wheel is braked and the rotation decreases, the differential drive wheel slips due to the action of the differential, and the brake is applied. This is because it is not desirable to be returned. The slip amount DVFR of the right driving wheel is differentiated by a differentiator 63 to calculate a temporal change amount thereof, that is, a slip acceleration GFR, and the slip amount DVFL of the left drive wheel is differentiated by a differentiator 64 to calculate the time. The target 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 65,
Referring to the GFR (GFL)-. DELTA.P conversion map shown in the figure, a change amount .DELTA.P of the brake fluid pressure for suppressing the slip acceleration GFR is obtained. Similarly, the slip acceleration G
FL is sent to the brake fluid pressure change amount (ΔP) calculation unit 66,
Referring to the GFR (GFL)-. DELTA.P conversion map shown in FIG. 14, the change amount .DELTA.P of the brake fluid pressure for suppressing the slip acceleration GFL is obtained.

Further, the change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFR output from the ΔP calculation section 65 is described.
Is supplied to a ΔP-T conversion unit 67 that calculates the opening time T of the inlet valve 17i when the switch S2a is closed, that is, when the control start / end determination unit 69 determines that the control start condition is satisfied. That is, the valve opening time T calculated by the ΔP-T converter 67 is used as the brake operation time FR of the right driving wheel WFR. Similarly, the change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFL output from the ΔP calculation unit 66 is determined when the switch S2b is closed, that is, the control start condition by the control start / end determination unit 69. ΔP-T for calculating the opening time T of the inlet valve 18i at the time of establishment and stability
The conversion unit 68 is provided. That is, the ΔP-T conversion unit 68
The valve opening time T calculated in the above is different from the left driving wheel WFL.
Of the brake operation time FL. This suppresses the occurrence of the above-mentioned slip due to the left and right drive wheels WFR and WFL.

In FIG. 14, when the brake is applied at the time of turning, in order to strengthen the brake of the drive wheel on the inner wheel side,
The inner wheel side at the time of turning is shown by a broken line a. In this way, when the load shifts to the outer wheel side during turning and the inner wheel side is liable to slip, the change ΔP of the brake fluid pressure is made larger on the inner wheel side than on the outer wheel side. At times, the inner ring side can be prevented from slipping.

Here, FIGS. 20 (A) and (B) show flowcharts of the start determination and the end determination of the slip control, respectively. In FIG. 20 (A), the condition A is the four control start conditions,. , And OR condition, and condition B is three of the four control start conditions excluding the control start condition satisfied in condition A among the four control start conditions.
OR, and the condition C is the four control start conditions,
, Are OR conditions of two control start conditions excluding the condition satisfied in condition A and the condition satisfied in condition B. For example, when the vehicle is traveling on a low μ road such as an icy road, the acceleration of the engine output due to the depression of the accelerator pedal causes the drive wheels WFR, WFL to accelerate the slip amount DVi (DVi> α) exceeding the slip determination value α. When a slip occurs, the engine torque sensor 72 detects an engine drive torque T of a predetermined torque value T ₀ (4 kg · m) or more due to the increase of the engine output, and the main throttle idle SW is turned off by depressing the accelerator pedal. As a result, the three control start determination conditions are satisfied. Then, the switches S1 and S2a, S2b are controlled to close by the control start / end determination unit 69, and the engine torque control according to the slip amount DV of the drive wheels WFR, WFL and the slip control by the braking control are started. In this case, even if the load operation speed of the accelerator pedal obtained by the main throttle position sensor 26 does not reach a plus predetermined value or more, the control start condition
The start determination of the slip control is performed when any one of the three conditions is satisfied.

On the other hand, in FIG. 20 (B), the condition A is an OR condition of the four control end conditions,..., And the condition B is the above condition A of the four control end conditions.
OR of the three control end conditions excluding the control end condition satisfied in
And the condition C is the four control end conditions,.
Of these, the OR condition of the two control end conditions excluding the condition satisfied in condition A and the condition satisfied in condition B. In the state after the start of the slip control,
For example, when the drive wheels WFR and WFL converge to the acceleration slip of the slip amount DVi (DVi ≦ α) equal to or less than the slip determination value α due to a decrease in the engine output due to the full return operation of the accelerator pedal, the main throttle position sensor 26 The three control end conditions are satisfied by detecting a load operation speed equal to or more than a minus predetermined value in accordance with the full return operation of the pedal, and turning on the throttle idle SW by the full return operation of the accelerator pedal. Then, the switches S1 and S2a, S2b are opened by the control start / end determination unit 69, and the engine torque control according to the slip amount DV of the drive wheels WFR, WFL and the slip control by the braking control are ended. In this case, the engine torque sensor 72 detects the predetermined torque value T ₀ (4 kg ·
Even if the engine drive torque T less than m) is not detected, the end of the slip control is determined when any one of the above-mentioned control end conditions is satisfied.

Therefore, according to the acceleration slip prevention device having the above configuration, the start / end of the slip control is determined by the wheel speed sensor.
Slip amount DVi obtained according to the vehicle speed signal from 11-14
The input drive sensor is different from the input drive sensor in terms of the engine drive torque obtained by the engine torque sensor 72, the opening degree of the main throttle valve THm23 obtained by the main throttle idle SW 28, and the load operation speed obtained by the main throttle position sensor 26. Since the control is performed by combining any three of the four independent control start conditions, even if an abnormality occurs in a certain sensor or SW, for example, the remaining sensors and SW
The start / end determination of the slip control can be accurately performed by satisfying the combination of the conditions. Therefore, stable control start / end timing can always be obtained.

In this embodiment, any three of the four independent control start conditions (A to A) with different input sensors or SWs are used.
When the condition C) was satisfied, the start of the slip control was determined. For example, as shown in FIG.
When any of the independent control start conditions having different SWs is satisfied, the start of slip control is determined, and the drive wheel WF is determined.
The configuration may be such that the slip suppression control of R and WFL is easily started. In this case, similarly to the above-described embodiment, even if an abnormality occurs in any of the sensors or SWs, an appropriate control start determination can be made with any of the remaining sensors and SWs.

Further, the slip determination unit 70 used for the first-half control start condition outputs a slip determination signal when the slip amount DVi exceeds the slip determination value α, but the change rate of the slip amount is stored in the slip determination value storage unit 71 in advance. The slip determination signal β may be output when the value exceeds the slip determination value β, or the slip determination may be performed using a slip ratio instead of the slip amount DVi. further,
If the drive wheel acceleration exceeds the slip determination value γ stored in advance in the slip determination value storage unit 71, a slip determination signal may be output.

[Effects of the Invention] As described above in detail, according to the present invention, it is possible to accurately determine a state in which a slip easily causing instability of the vehicle body is generated, and to start the slip control at an appropriate timing to ensure the occurrence of the slip. The effect that it becomes possible to suppress it.

[Brief description of the drawings]

FIG. 1 (A) is an overall configuration diagram of an acceleration slip prevention device for a vehicle according to an embodiment of the present invention, and FIG.
FIG. 2A is a configuration diagram showing an engine intake system, and FIG.
FIG. 3 is a block diagram showing the control of the traction controller for each functional block, FIG. 3 is a diagram showing the relationship between the centripetal acceleration GY and a variable KG, and FIG.
FIG. 5 shows the relationship between the centripetal acceleration GY and the slip correction amount Vg, and FIG. 6 shows the relationship between the temporal change ΔGY of the centripetal acceleration and the slip correction amount Vd. 7 to 12 show the relationship between the vehicle speed VB and the variable Kv, respectively, and FIG. 13 shows the variable KB from the start of the brake control.
FIG. 14 is a diagram showing the relationship between the temporal change amount GFR (GFL) of the slip amount and the change amount ΔP of the brake fluid pressure, and FIGS. 15 and 18 show the slip ratio S and FIG. 16 is a diagram showing the relationship between the friction coefficient μ of the road surface, FIG. 16 is a diagram showing the Tlim-t characteristic, FIG. 17 is a diagram showing the Tlim-VB characteristic, FIG. 19 is a diagram showing the state of the vehicle at the time of turning, FIGS. 20 (A) and (B) are flowcharts respectively showing a start determination and an end determination of the slip control by the acceleration slip prevention device for the vehicle, and FIG. 21 shows another embodiment of the slip control start determination. It is a flowchart. WFR, WFL …… Drive wheel, WRR, WRL …… Driving wheel, 11-14 ……
Wheel speed sensor, 15 ... Traction controller, 16
… Engine, 17, 18… Wheel cylinder, 23… Main throttle THm, 24… Sub throttle valve THs, 26… Main throttle position sensor, 27… Sub throttle position sensor, 28… Main throttle idle SW .., 69... Control start / end determination section, 70... Slip determination section, 71... Slip determination value storage section, 72.
…… Shift lever position SW, S1, S2a, S2b …… Switch.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Shimada 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Katsunori Ueda 5-33-8 Shiba, Minato-ku, Tokyo (56) References JP-A-63-31866 (JP, A) JP-A-61-67634 (JP, A)

Claims (1)

(57) [Claims] 1. A drive wheel slip amount detecting means for detecting a slip amount generated on a drive wheel based on a drive wheel speed; a separate drive information detecting means for detecting a plurality of types of different drive information; When each of the driving information detected by the driving information detecting means satisfies a control start condition in which a judgment condition set independently in advance is combined, the driving according to the slip amount detected by the driving wheel slip amount detecting means is performed. A control start determining means for starting torque control, wherein the driving information detecting means includes a driving torque detecting means for detecting a driving torque of an engine; The driving torque of the engine detected by the torque detecting means is the maximum torque at which no slip occurs on an ultra-low μ road where the road surface friction coefficient is not zero. An acceleration slip prevention device for a vehicle, comprising: