JP2518026B2 - Acceleration slip control device - Google Patents

Description

The present invention relates to a technique for controlling slip during vehicle acceleration.

[Prior Art] Conventionally, a technique has been developed in which the slip generated on the drive wheels during vehicle acceleration is suppressed within a predetermined slip amount range to increase the road surface friction coefficient on a slippery road surface and improve the acceleration performance of the vehicle. There is. Such techniques include, for example, JP-A-62-121839 and JP-A-63-14.
As disclosed in Japanese Patent Publication No. 9250, there is a technique in which the slip amount of a drive wheel obtained from a vehicle speed and a drive wheel speed is controlled within a predetermined target slip amount range by controlling an engine output or a brake.

[Problems to be Solved by the Invention] However, the conventional technique has a problem that the acceleration performance of the vehicle cannot be maximized for the following reasons, and there is room for further improvement.

When the drive wheel slips when accelerating on a slippery road surface such as a snowy road or a frozen road, the driving force and the lateral drag force change as the slip amount increases. That is, the driving force initially increases as the slip amount increases, and then gradually decreases after reaching the maximum point. on the other hand,
The lateral drag force decreases as the slip amount increases. Further, the degree to which the driving force and the lateral drag force change depending on the slip amount changes depending on the road surface condition. For example, the slip amount that maximizes the driving force varies depending on the slipperiness of the road surface. From this, conventionally, assuming various lateral road conditions and a slip amount at which the lateral drag force and driving force above a predetermined level are expected to be obtained, the target slip amount of the driving wheels is calculated as shown in FIG. It was set as one. Therefore, in a road surface condition outside the assumed range, the optimum driving force may not be obtained, and the acceleration performance of the vehicle may deteriorate.

An object of the present invention is to achieve the maximum driving force on any road surface by solving the above problems.

[Means for Solving the Problems] As means for achieving the above object, the acceleration slip control device of the present invention is, as illustrated in FIG. 1, a drive wheel MA based on a vehicle speed and a drive wheel speed. Acceleration slip control including a slip amount calculating means MB for calculating the slip amount and a driving force control means MC for controlling the vehicle driving force so that the slip amount becomes the target slip amount of the drive wheels MA during vehicle acceleration. In the device, a slip amount change state detecting means MD for detecting a change state of the slip amount of the drive wheel MA, an acceleration change state detecting means ME for detecting a change state of the vehicle acceleration, a change state of the slip amount and the acceleration The optimum slip amount judging means MF for judging the optimum slip amount region based on the change state of the target slip amount and the target slip amount for correcting the target slip amount based on the judgment result of the optimum slip amount judging means MF. Slip amount correction means MG
And are provided.

[Operation] The acceleration slip control device of the present invention has the drive wheels calculated by the slip amount change state detection unit MD by the slip amount calculation unit MB.
The change state of the slip amount of the MA is detected, the change state of the vehicle acceleration is detected by the acceleration change state detecting means ME, and the optimum slip amount judging means MF judges the optimum slip amount region based on both the changing states. Next, the target slip amount correcting means MG
Corrects the target slip amount of the driving force control means MC based on the optimum slip amount region. Since the driving force control means MC controls the driving force so that the slip amount calculated by the slip amount calculating means MB becomes the target slip amount, the slip amount generated on the drive wheels MA during vehicle acceleration falls within the optimum slip amount region. The value will be reflected.

As the correction of the target slip amount by the target slip amount correction means MG, for example, a method of further increasing the driving force generated by the drive wheels MA can be considered. Alternatively, the target slip amount may be set as a function of the slip amount at which the maximum driving force is obtained, so that the amount of distribution of the driving force and the lateral drag force may be corrected to a predetermined state.

[Embodiment] An embodiment of the present invention will be described below together with the configuration and operation of a front-wheel drive vehicle equipped with this acceleration slip control device.
FIG. 2 is an overall configuration diagram of a vehicle including the acceleration slip control device 1 of the present embodiment.

As shown in the figure, the vehicle has a front right wheel 5 and a front left wheel 7 driven by an engine 3, and a rear right wheel 9 and a rear left wheel 11 that are driven wheels. Further, in the intake system 13 of the engine 3, a fuel injection valve 19 that injects fuel into the intake manifold 17 to supply fuel to the combustion chamber 18 according to the intake amount, and an intake amount according to the depression amount of the accelerator pedal 21. Main throttle valve 23 for restricting the
A sub-throttle valve 27 that limits the intake amount based on the drive signal from 25 is provided.

The vehicle wheel and the engine 3 are provided with sensors for detecting the operating state, and the detection values of the sensors are input to the electronic control unit 25. That is, the right front left wheel 5,7 and the right rear left wheel 9,11 of the vehicle, the right front wheel rotation speed sensor 31, the left front wheel rotation speed sensor 32, the right rear wheel rotation speed sensor 33, the left to detect the respective rotation speed. Rear wheel rotation speed sensor
34 are provided. The main throttle valve 23 of the intake system 13 of the engine 3 is provided with an idle switch 37 for detecting the full closing of the main throttle valve 23 and a throttle position sensor 38 for detecting the throttle valve opening θM. An ignition system (not shown) of the engine 3 is provided with a rotation speed sensor 39 for detecting the engine speed NE.

Electronic control device that controls the acceleration slip control device 1
As shown in FIG. 3, 25 is a well-known CPU 40, ROM 41, RAM 4
2. It is configured as a logical operation circuit centering on the backup RAM 43 and the like, and is connected to the input port 45 and the output port 46 via the common bus 44 to perform input / output with the outside.

The detection signals of the idle switch 37, the throttle position sensor 38, and the rotation speed sensor 39 described above are directly input, and the detection signals of the rotation speed sensors 31 to 34 of the left, right, left, and right wheels are input through the waveform shaping circuit 48 to the input port 45. Is input to the CPU 40. On the other hand, a sub-throttle valve 27 is connected to the output port 46 via a drive circuit 49, and a drive signal built in the sub-throttle valve 27 receives a control signal from the CPU 40.

Next, a series of processes for the acceleration slip control performed by the electronic control unit 25 will be described based on the flowchart of the acceleration slip control routine shown in FIG. This acceleration slip control routine is repeatedly executed by the CPU 40. In the acceleration slip control routine, it is first determined whether or not a predetermined time ΔT (for example, 5 ms) has elapsed since the previous processing of step 110 and thereafter (step 100), and when it is determined that the predetermined time ΔT has elapsed, Next, based on the detected values of the respective rotation speed sensors 31 to 34, the wheel speed V that is the peripheral speed of the right-left front wheel and the right-left rear wheel.
FR, VFL, VRR, VRL are calculated (step 110). After the calculation of the wheel speeds VFR, VFL, VRR, VRC, the estimated vehicle speed VT0, the slip control start speed VT1, referred to in the following processing,
A process for obtaining the target speed VT2 for slip control is performed (step 120).

The estimated vehicle speed VT0 is determined by the driving wheels (here, the right front left wheel 5,
This is the vehicle speed that is the reference when calculating the acceleration slip amount in 7), and the wheel speed VFR, V
It is the value calculated from FL and estimated.

VT0 = (VFR + VFL) / 2 (1) The start speed VT1 of the slip control is a reference value when it is determined whether the acceleration slip control of the drive wheel is large and the acceleration slip control is started. Therefore, it is calculated based on the following equation (2).

VT1 = VT0 + ΔV1 (2) ΔV ... Start slip amount (for example, 6 km / h) The target speed VT2 of the slip control becomes the target of the acceleration slip control of the drive wheels when the acceleration slip control of the drive wheels is started. If the target slip amount is ΔV2 ′, which is the speed, the following expression (3) is obtained.

VT2 = VT0 + △ V2 '… (3) △ V2'… △ V2 + △ VT2 △ V2… Constant (for example, 2km / h) △ VT2 ・ ・ ・ VT2 correction value (described later) Calculation of reference speeds VT0, VT1, VT2 After that, whether the slip control flag FP is set (= 1) or cleared (=
It is judged whether it is 0) (step 130). The flag FP is set when the acceleration slip control is started in the process described later, and is reset when the acceleration slip control is ended. If it is determined that the slip control is being performed, the processing of the following steps 140 to 170 is bypassed and the subsequent processing is performed.If it is determined that the slip control is not being performed, first, as shown below, Conversion processing is performed (step 140).

That is, αTN ← O, αTMINO ← 9999, VT0CMP ← O, CαT ← O, ΣSLIP ←
O, ΔVT2 ← O processing is executed.

The contents of each initialized variable will be sequentially described when the corresponding process is described.

After initializing each variable, it is determined whether or not an acceleration slip has occurred (step 150).

That is, the following equation (4) is determined, and if satisfied, it is determined that an acceleration slip has occurred.

VT1 <(VFR + VFL) / 2 (4) VT1 ... Start speed of slip control calculated by the equation (2) VFR ... Right front wheel speed VFL ... Left front wheel speed When it is determined that no slip occurs, When returning to the beginning of this acceleration slip control routine and determining that a slip has occurred, first, the slip control flag FP indicating that the slip control is in progress is set (= 1, step 160), and then the slip control is ended. The slip control end flag FE shown is cleared (= 0, step 170).

After the initialization processing at the start of the acceleration slip control in steps 140 to 170 is completed, or after it is determined in step 130 that the slip control is already in progress, the sub-throttle control opening degree calculation is executed (step 180). In this calculation, the time differential value s of the sub-throttle opening command value θs is calculated by the following equation (5) based on the target speed VT2 and the estimated vehicle speed VT0.

s = K {α · ΔV + β · Δ} (5) where K is a coefficient that determines responsiveness, α is a proportional gain,
β is the differential gain, ΔV is the target speed VT2 and the estimated vehicle speed V
The difference from T0 (VT2-VT0) and Δ are their time derivative values.

By using the value of s, the driving routine of the sub-throttle valve 25 (not shown) is repeated every predetermined time, so that the opening degree and the opening speed of the sub-throttle valve 25 are actually controlled.

After executing the sub-throttle control opening calculation, the section speed VT0
It is determined whether CMP is "zero" (step 210). This section speed VT0CMP is initialized in step 140 and is updated by the processing described later. If it is determined that the section speed VT0CMP is "zero", then it is determined whether the estimated vehicle speed VT0 is "zero" (step 220).
If the estimated vehicle speed VT0 is "zero", that is, if the vehicle is stopped, the process returns to the beginning of this acceleration slip control routine. When the estimated vehicle speed VT0 is not "zero" when the sectional speed VT0CMP is "zero", the sectional speed VT0CMP is calculated based on the equation (6) (step 230).

VT0CMP = VT0 + 1.25 (6) As a result, the section speed VT initialized in step 140
0CMP is updated to a value obtained by adding the estimated vehicle speed VT0 and the speed of 1.25 km / h. This section speed VT0CMP is a value to be referred to when determining the increase amount of the estimated vehicle body speed VT0. Here, the speed “1.25 km / h” is added to the estimated vehicle speed VT0, but the speed to be added may be in the range of 1.25 ± 0.75 km / h. It should be noted that the value to be added can optimally reflect the road surface condition in the calculation within the range of 1.25 ± 0.75 km / h, but may be appropriately changed up to about 5 km / h.

After the section speed VT0CMP is renewed (step 230), or after it is judged that it has been renewed by the previous time (step 210), then the section speed VT0CMP and the estimated vehicle body speed VT are calculated based on the following equation (7).
The magnitude relationship with 0 is judged (step 240).

VT0 ≧ VT0CMP (7) If it is determined that the section speed VT0CMP is larger than the estimated vehicle speed VT0, the acceleration counter CαT is incremented (CαT = CαT + 1) (step 250),
Next, the current slip amount ΔSLIP at the time of the current calculation is calculated based on the following equation (8) (step 260).

ΔSLIP = (VFR + VFL) / 2− (VRR + VRL) / 2 (8) The acceleration counter CαT is used when calculating the vehicle body acceleration αT, which will be described later.

After calculating the current slip amount ΔSLIP, the integrated slip amount ΣSLIP which is the integrated value of the current slip amount ΔSLIP is calculated based on the following equation (9) (step 270).

ΣSLIP = ΣSLIP + ΔSLIP (9) After calculating the integrated slip amount ΣSLIP, it is determined whether or not the conditions for ending slip control are satisfied (step 28).
0). The determination of the end condition of the slip control here is made based on whether or not the idle switch 37 outputs a fully closed signal of the main throttle valve 23. If the conditions for ending the slip control are not satisfied, the process returns to the beginning of this acceleration slip control routine.

The above-described steps 250 to 270 are repeated during acceleration slip control until the determination in step 240 satisfies the expression (7). During this repetition, when the vehicle accelerates and the formula (7) is satisfied, that is, when the estimated vehicle body speed VT0 reaches the section speed VT0CMT, it is necessary to increase the estimated vehicle body speed VT0 by 1.25 km / h. The vehicle body acceleration αT indicating the elapsed time is calculated based on the following equation (10) (step 29
0). Note that the vehicle body acceleration αT is used for convenience as the value that reflects the actual acceleration, which is the time required for the vehicle body to increase by 1.25 km / h. Therefore, the actual vehicle acceleration increases as αT decreases.

αT = CαT × ΔT (10) CαT… Acceleration counter ΔT… Repeat cycle of this acceleration slip control routine Next, the average slip amount ▲ ▼ in the section where the estimated vehicle speed VT0 increases by 1,25 km / h is shown below ( Equal out based on equation 11) (step 300).

After calculating the average slip amount ▲ ▼, the section speed VT0CMP is updated by the formula (6) in preparation for the next calculation (step 310), and the acceleration counter CαT is cleared (step
320) and clearing the integrated slip amount ΣSLIP (step 330) are sequentially executed.

Next, reference speed correction calculation processing is executed (step 34
0). As shown in FIG. 5, in this reference speed correction calculation processing, the vehicle body acceleration αT and the average slip amount ▲ ▼ are arranged in time order in steps 350 to 460, and the correction value ΔVT2 is updated in steps 470 to 510. is there.

That is, first, the vehicle body acceleration αT and the average slip amount ▲
The array variable αTN for arranging ▼ and ▼ is incremented (αTN = αTN + 1) (step 35
0), and then it is determined whether or not this array variable αTN is 3 or less (step 360). If the array variable αTN is the value 3 or less, it is then determined whether the array variable αTN is the value 1 (step 370). If the value is 1, the process based on the following equation (12) is executed (step 370). Step 380).

▲ ▼ (4-αTN) ← ▲ ▼ (12) As a result, if αTN is 1 here, ▲
▼ (3) Current calculated average slip amount ▲
▼ is stored.

After storing the average slip amount ▲ ▼ in (3), this reference speed correction calculation routine is temporarily terminated.
Next, when this calculation routine is started, steps 350 to 3
70 are sequentially executed. Here, the array variable αTN has the value 2
Then, the processing based on the following equation (13) is executed (step 390).

αT (5-αTN) ← αT (13) Therefore, if αTN is 2 here, αT
The current vehicle body acceleration αT is stored in (3).

Then, the processing according to the equation (12) is executed (step 38
0), ▲ ▼ (2) shows the current average slip amount ▲
▼ is stored. In this way, the processing by the equations (12) and (13) is repeated until the array variable αTN reaches 3, and the values are stored in the following order.

▲ ▼ (3), αT (3), ▲ ▼
(2), αT (2), ▲ ▼ (1) As a result of repetition, when it is determined that the array variable αTN becomes 4 or more (step 360), then the following (14)
The processing shown in Expressions (20) is sequentially executed (step
400 to 460).

αT (3) ← αT (2)… (14) αT (2) ← αT (1)… (15) αT (1) ← αT… (16) ▲ ▼ (3) ← ▲ ▼ (2)… (17) ) ▲ ▼ (2) ← ▲ ▼ (1)… (18) ▲ ▼ (1) ← ▲ ▼ (0)… (19) ▲ ▼ (0) ← ▲ ▼… (20) As a result, the array variable αTN is If the value is 4 or more,
Body acceleration αT and average slip amount stored up to the previous time ▲
▼ and are shifted in order, and αT (1) and SLIP
In (0), the currently calculated vehicle body acceleration αT and the average slip amount ▲ ▼ are stored.

After rearranging, αT (3), αT (2), αT
It is stored in (1). The minimum value of the vehicle body acceleration αT (the value of the largest acceleration) is retrieved and set to the minimum vehicle body acceleration αTMIN (step 470). After setting the minimum vehicle body acceleration αTMIN, the magnitude of the currently set minimum vehicle body acceleration αTMIN is determined based on the following equation (21) (step 480).

αTMIN <αTMINO + △ αT… (21) αTMINO… minimum value of αTMIN up to the previous time △ αT… constant As a result, the acceleration of the vehicle body corresponding to the currently calculated minimum vehicle body acceleration αTMIN is equal to or greater than the vehicle body acceleration at the previous time or the initial setting value. Will be determined.
Here, when it is determined that the acceleration is not greater than the actual acceleration of the vehicle body up to the previous time, this routine is once ended and the acceleration is improved (αTMIN <αTMINO
If it is determined to be + ΔαT), the process proceeds to the next change pattern search process (step 490).

The change pattern search processing is performed by αT (1) to αT (3),
And the vehicle body acceleration αT and the average slip amount stored in ▲ ▼ (1) to ▲ ▼ (3) ▲
The search map shown in FIG. 6 is searched according to the change state of ▼ and ▼, and the revision value ΔVT2 of the correction value ΔVT2 used in the equation (3)
VT20 is calculated. The search map shown in FIG. 6 has three changing states, that is, αT (1) to αT.
(3) and ▲ ▼ (1) to ▲ ▼
Although (3) is used, by increasing the number of detections of this change state, a more accurate renewal value ΔVT20 can be calculated.

Hereinafter, some examples of the process of calculating the renewal value ΔVT20 will be described with reference to FIG.

(1) When the values stored in αT (1), αT (2), αT (3), are successively increasing, and ▲ ▼ (1), ▲ ▼ (2), ▲
When the value stored in (3) is sequentially increased, the process determined from both patterns, that is, the process indicated by in FIG. 6 is executed. In this case, it is determined that the target speed VT2 obtained from the equation (3) is too high, that is, the target slip amount V2 'is excessive, and the following equation (22) is determined.

ΔV2 ′> ▲ ▼ (1) (22) ΔV2 ′ ... Target slip amount (ΔV2 + ΔVT2) Here, if the expression (22) is satisfied, the processing of the following expression (23) is executed.

ΔVT20 = ▲ ▼ (1) -ΔV2 (23) If the formula (22) is not satisfied, the next step is performed.

In the processing of FIG. 6, when the average slip amount ▲ ▼ decreases and the vehicle body acceleration αT decreases (the actual vehicle acceleration increases), the actual acceleration slip amount is SLIPed.
It is judged that it is possible to increase the actual acceleration of the vehicle by making it the same as the minimum average slip amount ▲ ▼ in (1), and the revision value ΔVT20 of the correction value in equation (3) is set to (23).
It is set as shown in the formula.

(2) αT (1), αT (2), αT (3) increase in sequence, and ▲ ▼ (1), ▲ ▼
If (2) and ▲ ▼ (3) do not change, the vehicle actually accelerates and the average slip amount ▲ ▼ has not changed, so the current state is maintained as shown in FIG. That is, the current target speed VT2 is maintained.

(3) αT (1), αT (2), αT (3) increase in sequence, and ▲ ▼ (1), ▲ ▼
If (2) and ▲ ▼ (3) become smaller,
It is determined that the vehicle is actually accelerating and the average slip amount ▲ ▼ is increasing, and the determination of the following equation (24) is performed as shown in FIG.

ΔV2 ′ <▲ ▼ (1) (24) If the expression (24) is satisfied, the processing of the expression (23) is executed. As a result, the maximum average slip amount ▲
▼ can be set as the target slip amount ΔV2 ′.

(4) The process shown in FIG. 6 and FIG. 6 is a process for maintaining the current acceleration state in the minimum slip state by setting the minimum value MIN (▲ ▼) of the average slip amount ▲ ▼ as the target slip amount ΔV2 '. Is.

(5) FIG. 6 and FIG. 6 show the process when the actual acceleration does not change, and in order to obtain the current acceleration state with the minimum slip amount, the minimum value of the average slip amount ▲ ▼
This is a process of setting MIN (▲ ▼) as the target slip amount ΔV2 ′.

(6) FIG. 6 and FIG. 6 show the process when the actual acceleration is decreased. In the case of, the average slip amount ▲ ▼ is also decreased as the actual acceleration is decreased. Was obtained ▲ ▼ (3)
The value of is the target slip amount ΔV2 '. In the case of, the average slip amount ▲
Since ▼ is increasing, the minimum average slip amount ▲
The value of ▲ ▼ (3), which is ▼, is set as the target slip amount ΔV2 ′.

(7) FIG. 6 is a process in the case of a pattern in which the actual acceleration once decreases and then accelerates again,
In the case of, since the average slip amount ▲ ▼ has decreased, it is the most accelerated and the average slip amount ▲ ▼
▼ is small ▲ ▼ (1) is the target slip amount △
V2 '. In this case, since the average slip amount ▲ ▼ is increasing, the average slip amount ▲ ▼ when the actual acceleration is increasing is stored.
▼ Set the value of (1) as the target slip amount ΔV2 '. In the case of, the average slip amount ▲ ▼ has decreased once and then increased. Therefore, since the actual acceleration state and the slip state are almost the same, whether there is room to increase the target slip amount ΔV2 ′ is determined by the equation (25) below, and if this determination condition is satisfied. The following formula (26) is processed.

△ V2 '<MIN (▲ ▼)… (25) △ VT20 = MIN (▲ ▼)-△ V2… (26) As a result, the target slip amount △ V2´ is smaller than the minimum value of the current average slip amount ▲ ▼. For example, the target slip amount ΔV2 ′ becomes the minimum value of the average slip amount ▲ ▼.

(8) In the case of FIG. 6, ..., It is the processing in the case of the pattern in which the actual acceleration once increases and then decreases. In the case of and, the average slip amount ▲ ▼
Is simply decreasing or increasing, the value of ▲ ▼ (2) that shows the maximum acceleration is the target slip amount ΔV2 '.
Set to. That is, the value of (2) (2) is determined to be the optimum slip amount, and this is set as the target slip amount ΔV2 '. In the case of, the average slip amount ▲ ▼ changes corresponding to the actual increase of the acceleration. Therefore, since the actual slip state is the optimum state, the target slip amount ΔV2 ′ is the minimum value MI of the average slip amount ▲ ▼.
Only when it is smaller than N (▲ ▼), the target slip amount ΔV2 ′ is changed to the minimum value MIN (▲ ▼).
In the case of, when the average slip amount ▲ ▼ reaches the minimum value, the actual acceleration is maximum,
This minimum average slip amount ▲ ▼ is set to the target slip amount ΔV2 '.

The other processing for obtaining the renewal value ΔVT20 will be described with reference to FIG. The arrow (→) in FIG. 6 performs a process having the same effect as the process in the arrow direction, and the symbol N / A indicates
The case where the determination of the slip state is impossible is shown, and the target speed VT2 so far is maintained here.

After performing the change pattern search based on FIG. 6, that is, after maintaining or updating the renewal value ΔVT20, the minimum vehicle body acceleration αTMIN calculated in step 470 of FIG. 5 is set to the next reference minimum vehicle body acceleration αTMINO ( Step 500), then the renewal value ΔVT20 is set to the correction value ΔVT2 of the equation (3) (step 510), and this routine is once terminated.

After completing the reference speed correction calculation routine shown in FIG.
Next, the process proceeds to step 280 in FIG. 4, and if the slip control ending condition is not satisfied (step 28
0), returning to the beginning of this acceleration slip control routine, and repeating the above-mentioned processing.

On the other hand, when the conditions for ending the slip control are satisfied, the slip control in progress flag FP is next cleared (= 0) (step 520), and then the slip control end flag FE is set (= 1) ( Step 530) returns to the beginning of this acceleration slip control routine. This prepares for the next generation of acceleration slip.

By the processing described above (FIGS. 4 to 6), the correction value ΔVT2 is corrected to the optimum value reflecting the road surface state, and the target speed VT2 is updated. As a result, the time differential value S (equation (5)) of the sub-throttle opening command value is changed, and the actual opening of the sub-throttle valve 25 is controlled so that the slip amount of the driving wheel becomes optimum.

Next, an example of control of acceleration slip by the present acceleration slip control device 1 will be described with reference to FIG.

(I) When the opening of the main throttle valve 23 is started at time t _{0 in} FIG. 7, Is more than the driven wheel speed VR (= estimated vehicle speed VT0),
At time t ₁ when the start speed VT1 increases, acceleration slip control is started (step 150). This results in time t ₁
The target speed VT2 is set by (step 120), and the opening θs control of the sub throttle valve 25 is started (step 120).
180). Conventionally, the target speed VT2 that is set at this time t ₁
Indicates the end of the slip control as indicated by the solid line (step 28
It continues until 0). However, in the present acceleration slip control device 1, the change state of the vehicle body acceleration αT and the average slip amount ▲ ▼ are processed by the processing already described (FIGS. 4 to 6).
Of the target speed VT2 based on the change state of
Is calculated (step 490) and the target speed VT2 is a correction value Δ
It is corrected by VT2 (step 510). Below (II)
The correction state of the target speed VT2 and the operation associated with the correction will be described in (IV) to (IV).

(II) Further acceleration of the vehicle continues at time t ₁ ,
At time t ₂ when the driven wheel speed VR increases by 1.25 km / h from the state at time t ₁ (step 240), the vehicle body acceleration αT
And the average slip amount ▲ ▼ are calculated (steps 290, 300). This calculated value is shown in FIG.

After that, the vehicle body acceleration αT and the average slip amount ▲ ▼
Is calculated each time the driven wheel speed VR increases by 1.2 km / h, and changes, for example, from time t _{3 to} time t ₁₀ or as shown by or. For example, while the driven wheel speed VF is increasing (time t ₁ ~ time t _4), the average amount of slip ▲
▼ increases (~). Furthermore, while accelerating the driven wheel speed VR (time t ₁ - time t _6), the vehicle acceleration αT is increased (~).

(III) The calculated average slip amount ▲ ▼ and the vehicle body acceleration αT correspond to, for example, the average slip amount ▲ ▼ at the time point t ₂ and the vehicle body acceleration αT at the time point t ₃ , as shown in FIG. That is, the result of the average slip amount ▲ ▼ calculated at time t ₂ becomes the vehicle body acceleration αT obtained at time t ₃ . Such ▲ ▼ and αT
In the correspondence relationship with, the update value ΔVT20 is calculated based on the map of FIG. 6 (step 490), for example, at the time point.
At t ₅ , the correction value ΔVT 2 as shown by the dotted line is set.

(IV) By setting the correction value ΔVT2 as shown in (III) above, for example, the target speed VT2 is increased (step 120), and the drive wheel speed VF becomes higher than the conventional one as shown by the dotted line. Become. That is, the average slip amount ▲
▼ increases from time t _{8 to} time t ₁₄ as shown by the dotted line. Further, since the drive wheel speed VF is controlled so as to obtain the optimum drive force, the auxiliary drive wheel speed VR also increases faster than in the conventional case as shown by the dotted line. That is, the value of the vehicle body acceleration αT becomes small as shown by the dotted line at time t _{9 to} time t ₁₄ , and the actual acceleration of the vehicle becomes high.

As described above, the acceleration slip control device 1 of the present embodiment provides the largest acceleration of the vehicle with the appropriate slip amount of the drive wheels based on the change state of the average slip amount ▲ ▼ and the change state of the vehicle body acceleration αT. The slip amount of the drive wheels is controlled so that Therefore, the slip amount of the drive wheel that gives the maximum acceleration on any road surface is detected, and the actual slip amount of the drive wheel is controlled to this target slip amount. As a result, the maximum acceleration is always obtained regardless of the state of the road surface, so that an extremely excellent effect of improving the acceleration state of the vehicle is achieved. Further, as shown in this embodiment, by applying it to a front-wheel-drive vehicle which has a high directional safety in principle, it is possible to reduce the lateral drag force as much as the directional stability is high, and to perform control to maximize the acceleration of the vehicle. It has an excellent effect that it can be performed.

It should be noted that the present invention is not limited to the above embodiments, and various embodiments can be carried out without changing the gist of the invention. For example, the invention is not limited to a front-wheel drive vehicle, but may be applied to a rear-wheel drive vehicle or an all-wheel drive vehicle. or,
The control of the driving force of the drive wheels is not limited to controlling the opening degree θS of the sub-throttle valve 23, but may be performed by controlling the ignition timing or the fuel injection amount, or by controlling the vehicle brake. It may be configured to be performed by.

[Advantages of the Invention] The acceleration slip control device of the present invention controls the slip amount by determining the optimum slip amount region in which the driving force is the largest based on the change state of the slip amount and the change state of the vehicle acceleration. As a result, the slip amount of the drive wheel becomes a value that reflects the optimum slip amount region. Therefore, the slip amount of the driving wheels can be matched with the optimum slip amount, and the driving force of the vehicle can be controlled to be maximized. Further, it is possible to obtain the slip amount at which a predetermined driving force is obtained based on the region where the driving force of the driving wheels is maximum, and to set the balance between the driving force and the lateral drag force to a desired value.

As a result, there is an extremely excellent effect that the controllability of the driving force and the lateral drag force of the vehicle is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a basic configuration of an acceleration slip control device of the present invention, FIG. 2 is an overall configuration diagram of a vehicle including an acceleration slip control device of an embodiment, and FIG. 3 is a block of its electronic control device. 4 and 5 are flowcharts of the acceleration / slip control routine, FIG. 5 is a flowchart of the reference speed correction calculation routine, FIG. 6 is an explanatory diagram of a map referred to in the change pattern search processing, and FIG. 7 is an embodiment. And FIG. 8 is an explanatory view of a conventional example. MA ... driving wheel, MB ... slip amount calculation means, MC ... driving force control means, MD ... slip amount change state detection means, ME ... acceleration change state detection means, MF ... optimal slip amount determination means, MG: Target slip amount correction means, 1 ... Acceleration slip control device, 3 ... Engine, 5 ... Right front wheel, 7 ... Left front wheel, 9 ... Right rear wheel, 11 ... Left rear wheel, 25 ... … Electronic control device, 27 …… Sub throttle valve, 31 …… Right front wheel rotation speed sensor, 32 …… Left front wheel rotation speed sensor, 33 …… Right rear wheel rotation speed sensor, 34 …… Left rear wheel rotation speed sensor,

Claims (1)

(57) [Claims] 1. A slip amount calculating means for calculating a slip amount of a drive wheel based on a vehicle speed and a drive wheel speed, and a vehicle driving force so that the slip amount becomes a target slip amount of the drive wheel during vehicle acceleration. In an acceleration slip control device including a driving force control means for controlling the vehicle, a slip amount change state detecting means for detecting a change state of the slip amount of the driving wheel, and an acceleration change state detecting means for detecting a change state of the vehicle acceleration. An optimum slip amount determining means for determining an optimum slip amount region based on the change state of the slip amount and the change state of the acceleration, and the target slip amount is corrected based on the determination result of the optimum slip amount determining means. A target slip amount correcting means for performing the acceleration slip control device.