KR960014079B1 - Transmission controller - Google Patents

Abstract

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Description

Driving force control device for vehicle

1 is a conceptual diagram of the present invention.

2 is a diagram showing the configuration of the first embodiment of the vehicle driving force control apparatus of the present invention.

3 is a flowchart showing a control program for calculating the drive slip amount in the same example.

4 is a flowchart showing a control program for setting slip reference values in the same example.

5 is a flowchart showing a control program for driving torque control in the same example.

6 is a time chart for explaining the operation of the example.

7 (a) and 7 (b) are time charts showing control effects in different driving situations in the first embodiment and the conventional example, respectively.

8 is a flowchart showing the main part of the control program of the second embodiment of the vehicle driving force control apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

1L: Front wheel (drive wheel) 1R: Front wheel (drive wheel)

2L: Rear wheel (drive wheel) 2R: Rear wheel (drive wheel)

3: engine 4: wheel rotation sensor

5 wheel rotation sensor 6 wheel rotation sensor

7: wheel rotation sensor 11: CPU

12: fuel supply control unit 13-1: cylinder

13-2: Cylinder 13-3: Cylinder

13-3: Cylinder 13-4: Cylinder

13-5: Cylinder 13-6: Cylinder

The present invention relates to a control device for a vehicle in which a driver's intended driving performance and driving stability at the time of an acceleration operation are made to be compatible.

As a conventional example of a vehicle drive control device in which a vehicle control for installing drive torque control is provided which variably controls the drive torque supplied to the drive wheel in accordance with the drive slip state when a wheel slip occurs in the drive wheel, for example, Japanese Patent Application No. 63 It was disclosed in -31830.

This conventional example aims at eliminating this drive slip by reducing and controlling the drive torque applied to the drive wheels so that the drive slip state becomes the slip target value (reference value). At that time, using the axel operation amount (which is substituted for the throttle opening degree), which is a parameter indicating the driver's willingness to accelerate, for example, as the absolute value of the axel operation amount increases, the slip target value is increased, and the driver's intended driving performance is realized. I am trying to.

However, the vehicle drive control apparatus of the above-described conventional example, however, the slip target value is increased uniformly as the amount of the accelerator operation increases, so that, for example, when the driver makes a bright operation with a sudden axel, the slip target value rapidly increases. As a result of the increase, a large driving slip is allowed at a larger target value, and the original function of the driving force control device, which secures the running stability when the driver performs an unexpected axel operation, is impaired.

According to the present invention, the slip reference value is changed in accordance with the actual change of the driving slip generated by the acceleration and deceleration to realize the driver's intended driving performance, and the driving is performed when the driver actually performs an operation in which the change of the driving slip is excessively increased. An object of the present invention is to provide a driving force control apparatus for a vehicle that can prevent the stability from being impaired.

For this purpose, the driving force control apparatus for a vehicle of the present invention, as shown in the concept of FIG. 1, includes starting slip detection means for detecting a driving slip state of a drive wheel, and slip reference value setting means for setting a slip reference value of the drive wheel. And a drive torque control means for performing drive torque control based on the detected drive slip state and the set slip reference value, wherein the change rate of the drive slip state until the change rate of the drive slip state reaches a predetermined value. And a slip reference value changing means for changing the slip reference value and storing the slip reference value at an upper limit value or a lower limit value when the rate of change of the driving slip state is equal to or greater than a predetermined value.

According to the present invention, on the basis of the drive slip state detected by the drive slip detection means and the slip reference value set by the slip reference value setting means, when the drive torque control means performs the drive torque control, the slip reference value changing means includes: the drive slip Until the rate of change of the state reaches a predetermined value, the slip reference value is changed according to the rate of change, so that the slip reference value is changed in accordance with the change of the driving slip state due to acceleration and deceleration, and an appropriate acceleration is obtained so that the driver's intended driving performance is changed. Obtained. In addition, the slip reference value changing means is stored in a constant value without changing the slip reference value in a driving situation in which the slip state may cause a change in the slip state when the rate of change of the drive slip state becomes equal to or greater than a predetermined value. Unreasonable damage to the above-mentioned running stability is prevented.

EXAMPLE

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 2 is a diagram showing the configuration of the first embodiment of the vehicle driving force control apparatus of the present invention, in which 1L and 1R denote left front wheels, right front wheels, 2L and 2R left and right wheels, right rear wheels, and 3 denote engines. This vehicle is a rear wheel drive car which drives the rear wheels 1L and 2R which are drive wheels by the engine 3, and wheel rotation sensors 4, 5, 6, and 7 are respectively near the wheels 1L, 1R, 2L, and 2R. ) Is also provided (the vehicle may be a front wheel drive vehicle).

The wheel rotation sensors 4 to 7 detect the rotation speed of each wheel as a pulse signal of the frequency corresponding to the rotation speed, and the pulse signal of the frequency according to the rotation speeds VFL, VFR, VRL, and VRR of each wheel obtained. Is input to the F / V converter 9 of the driving force control section 8. The driving force control unit 8 includes an F / V converter 9, an A / D converter 10, and a CPU 11, and the F / V converter 9 includes the wheel sensors 4-7. Is inputted to the A / D converter 10 by voltage conversion, and the A / D converter 10 digitally converts each input signal to the CPU 11. In addition, the CPU 11 uses a microcomputer, for example.

The CPU 11 executes the control programs shown in Figs. 3 to 5 based on the input wheel speeds (each wheel speed) VFL, VFR, VRL, and VRR, and is used for driving torque control. The slip reference value is controlled in accordance with the drive slip change rate.

This first embodiment also presupposes an engine control method for adjusting the torque applied to the drive wheels by adjusting the drive torque itself of the engine. The CPU 11 outputs the fuel supply cut signal FC to the fuel supply coat roll unit 12, and the signal FC supplies the fuel supply control unit 12 to the respective cylinders 13-1 to 13-6 of the engine. Injection pulses IP which are respectively outputted are cut off and fuel cut is performed.

In the control program of FIG. 3, which is repeated and executed at regular intervals (for example, 5 msec) by an operation system (not shown), first, in step 101, the rotational speed VFL of the left and right front wheels, which are the driven wheels, The rotational speeds VRL and VRR of the left and right rear wheels, which are the VFR and the driving wheels, are read from the corresponding wheel rotation sensors 4 to 7, respectively. In step 102, the average rotational speed VF of the front wheel (drive wheel) is calculated by VF = (VFL + VFR) / 2. In step 103, the average rotational speed VF of the rear wheel (drive wheel) is calculated by VF = (VRL + VRR) / 2, and in step 104, the drive slip amount S is calculated by S = VR-VF.

In the control program of FIG. 3, the CPU 11 can be used as drive slip detection means.

The control program of FIG. 4 is a control program executed after the program of FIG. 3, and only this control program is executed at a 100 msec period. First, in step 111 of FIG. 4, the average value Sav (n) of the data (because it is obtained every 5 msec is 20 data together) between 100 msec of the drive slip amount S obtained by the step 104 is set to Sav ( n) = (SN + Sn _-1 + ... + Sn _-19 ) / 20. Here, Sn, Sn- ₁ , Sn- ₁₉ represents the present value, the value before 5 msec, and the drive slip amount before 95 msec, respectively.

In the following step 112, using the average value Sav (n) obtained at this time and the average value Sav (n-1) obtained last time (100 msec before), the average change rate δSav (n) of the drive slip amount S is calculated as δSav (n ) = Sav (n) -Sav (n-1).

In the next step 113, the torque down command value TD determined as described above is read later, and accordingly it is judged whether drive torque control is currently performed. In the case where TD ≠ 0, where drive torque control has already been performed, the control advances to step 114, the slip reference value S * (n) is kept at the previous value S * (n-1), and the drive torque control If TD = 0 is not performed, the control is advanced after step 115 to change (update) the slip reference value.

That is, in step 115, the slip reference value S * (n) is set to the default value S * 1 only for the first time of the control, and in the next step 116, the average rate of change? Sav of the drive slip obtained in the step 112 is obtained. n) sets a limit by the map written in step 116, and sets this to the change data (DELTA) S * (n) of a slip reference value. At this time, it is assumed that the repayment value δSmax and the lower limit δSmin of the limiter are set to the slip maximum change rate and the slip minimum change rate to be allowed.

In step 117, the change data S * (n) obtained in step 116 is added to the previous value S * '(n-1) to obtain the current slip reference value data S *' (n), and again. A repeater is applied to the slip reference value data S * '(n) by means of a map written together in step 116, and finally the current slip reference value S * (n) is determined (updated). At this time, the lower limit of the limiter is set to the default value S * 1 of the slip reference value, and the value becomes a slip reference value before drive slip occurs (and when drive slip does not occur).

In addition, in the control program of FIG. 4, the CPU 11 is possible as sleep reference value setting means and sleep reference changing means.

The control program of FIG. 5 is a control program executed after the control program of FIG. 4, and this control program is executed at a 5 msec cycle. First, in step 121 of FIG. 5, the current drive slip amount S is read, and the slip reference value S * (n) previously obtained in step 122 is read, and both are compared in step 123. FIG. If Y> of S> S * (n), the process advances to step 124 to determine whether the torque down instruction amount TD is the maximum value TDmax. If NO of S≤S * (n), the process advances to step 125. Then, it is judged whether or not the torque down instruction amount TD is zero.

Since the determination of steps 124 and 125 becomes NO because the TD takes a value between the upper limit value and the lower limit value, in that case, the TD is determined in the following steps 126 and 127, respectively. The clementation (TD = TD + 1) and the decrementation (TD = TD-1) are performed. In the case of YES, steps 126 and 127 are skipped because the increment and declining, which are at or above the upper limit or the lower limit, are impossible. In step 128, the fuel supply cut signal FC corresponding to the torque down instruction amount TD is output from the CPU 11 to the fuel supply control unit 12.

In addition, in the control program of FIG. 5, the CPU 11 is possible as drive torque control means.

Next, the operation of this first embodiment will be described with reference to FIGS. 6 and 7 (a) and (b), comparing with the conventional example.

For example, in the case where the drive slip state changes as shown in the time chart of FIG. 6, in the section A in which the drive slip amount S is gradually increasing, the slip reference value S is first performed by the execution of step 115 of FIG. * (n) is set to the default value S * 1, and then the slip reference value S * (n) is at the same rate as the average change rate? Sav (n) of the drive slip by the execution of steps 116 and 117. It is changed (updated) to linear. Therefore, when the drive slip amount S gradually increases, the slip amount S * (n) is increased correspondingly, so that the drive slip amount S is arranged within the allowable range and never exceeds the slip reference value S * (n). Therefore, the determination of step 123 of the control program of FIG. 5 is NO, the torque down control is not started, and acceleration is intended by the driver.

The section B following the section A and the section C following the section B are sections in which the drive slip amount S increases rapidly and excessive drive slip exceeding the allowable range occurs. In these sections, since the change in the drive slip corresponding to the portion of the change in the drive slip, which is placed on the limiter in the map written in step 116, is not reflected in the update of the slip reference value in step 117, At a point in time (instantaneous t _{1 of} FIG. 6), the drive slip amount S exceeds the slip reference value S * (n), and the determination of step 123 of the control program of FIG. 5 returns from NO to YES, and the torque down The command value TD does not become zero by the execution of step 126 of FIG. Thus, the torque-down control of the instant t ₁ after the start is. After the start of the torque down control, since the determination of step 113 in FIG. 4 changes from NO to YES, step 114 is executed and the slip reference value S * (n) is the previous value S * (n-1). Is maintained.

According to such a change (or preservation) of the slip reference value, an effect that differs from the conventional example as described below is obtained.

First, the conventional example for comparison is demonstrated. For example, when a skilled driver symbolizes a situation in which the driver is turning while gradually accelerating (or a situation in which the driver is turning while gradually accelerating the height μ: case 1), a solid line is shown in FIG. 7 (b). Similarly, as the vehicle speed increases, the driving slip amount S also gradually increases, and if the acceleration continues further, the driving wheel loses driving force at a certain point (point A shown in the drawing), sudden driving slip occurs, and driving safety of the vehicle is impaired. Throw it away. In order to prevent such inconvenience, it is preferable to perform torque down control at the point A shown, and S * 11 is suitable as a slip reference value.

However, when the slip reference value is set to S * 11, a different driving situation, for example, a situation in which the driver of a beginner is turning while gradually accelerating (or a situation in which the driver is turning while slowly accelerating the low road): case In 2), as shown by the dotted line in FIG. 7 (b), the driving force loses the driving force at an earlier time (point B), so the timing of the torque down control is too late at the point A in the city. The driving stability of the vehicle cannot be secured. In this running situation, it is preferable to perform torque down control at point B in the city, and S * 12 of the city is appropriate as the slip reference value. However, if the slip reference value is set to the slip reference value S * 12, on the contrary, the driving situation of case 1 In this case, the timing for performing the torque down control is too early, resulting in a stalling feeling and deterioration in operability.

Since the optimum slip reference values differ individually depending on the road surface situation, the driver's skill, the vehicle characteristics, and the like, it is necessary to perform individual tuning based on these in order to achieve both driving performance and running stability.

On the other hand, in the vehicle driving force control apparatus of the present embodiment, as shown by the solid line and the dotted line in Fig. 7A, the optimum slip reference value according to the traveling situation is set. That is, in the driving conditions of the cases 1 and 2, the slip reference value is also gradually increased in the section in which the drive slip amount S is slowly increasing, so that the driver's intended driving performance is obtained. On the other hand, in the section where the drive slip amount S is rapidly increasing, the slip reference value reaches an upper limit value and is stored at a constant value (upper limit value) after the torque down control is started. As a result, the torque down control is performed at an appropriate timing corresponding to the points A and B in Fig. 7 (b) to ensure the running stability.

In addition, when the arc diameter due to the attachment of the puncture or the tenter tire decreases, slippage of the appearance occurs, so that the wheel speed detected by the vehicle speed sensor is detected as a larger value than the actual one, and the corresponding wheel is the driving wheel. The detection of the drive slip results in an erroneous detection, and in the case of a driven wheel, the detection delay of the drive slip is caused. In such a case, in the present embodiment, since the apparent slip gradually occurs as the vehicle speed rises even if its absolute amount is large, the rate of change decreases, so that the inconvenience can be corrected by correcting the apparent slip. .

8 is a flowchart showing the control program of the main part of the second embodiment of the vehicle driving force control apparatus of the present invention. This second embodiment adds an axel opening degree sensor (which may be substituted as a slot opening degree sensor) for detecting an accelerator opening, which is a parameter indicating a driver's acceleration request, in the configuration of FIG. It is configured similarly to the first embodiment except for inputting to the / D converter 10 and using the control program of FIG. 8 instead of the control program of FIG. 4 of the first embodiment.

(The description of the added drawings is omitted)

In the control program of FIG. 8 executed after the control program of FIG. 3, first, the axel opening degree L is read in step 131, and this L is compared with the predetermined value L ₀ in the next step 132. FIG. If here L> L _0, in that the acceleration demand is determined by the acceleration at step 134 is determined and set as the acceleration demand flag Fa in the step (133) (Fa = 1) , when no acceleration request requires L≤L ₀ Reset the flag Fa (Fa = 0).

In the following step 135, the step 139 branches perform the same control as those in the step 111 to the step 115 in FIG. 4 described above, and thus description thereof is omitted.

In step 140 following step 139, the state of the acceleration request flag is checked, and if there is an acceleration request of Fa = 1, control is displayed in step 141 to perform the same control as in the first embodiment, In the case where there is no acceleration request of Fa = 0, the control advances to step 142. In step 142, a repeater is applied by the map written in step 142 at the average change rate? Sav (n) of the drive slip, and this is set to the change data? S * (n) of the slip reference value.

At this time, by setting the upper limit value of the limiter to 0, the lower limit value is not set to prevent the increase of the setting reference value when there is no acceleration request and to allow the slip reference value to return to the default value S * 1 as soon as possible. .

In addition, in step 143 following step 141 and 142, slip reference value S * (n) is determined similarly to 1st Embodiment.

In the second embodiment, considering that there is a correlation between the acceleration demand of the driver and the occurrence of the driving slip, the first point is that the control of the step 141 and the step 142 is divided according to the presence or absence of the acceleration request. Except for the embodiment, the same effects as in the first embodiment can be obtained.

In addition, although the drive torque control by a fuel supply cut is employ | adopted in each said embodiment, it is not limited to this, For example, the slot frame which electrically controls the slot valve valve of an engine is also controlled, or the ignition timing of an engine. Control or brake control that applies pressure directly to the boiler cylinder may be used.

In this way, the vehicle driving force control apparatus of the present invention changes the slip reference value in accordance with the rate of change of the actual drive slip generated according to the acceleration and deceleration as described above, so that an appropriate acceleration is obtained and the driver's intended driving performance is obtained. In addition, when the actual change rate of the driving slip is excessive (over a predetermined value), the slip reference value remains at the upper limit or the lower limit. In the situation, the slip reference value is not changed, remains at a constant value, and the running stability is not impaired.

Claims (1)

Drive slip detection means for detecting a drive slip state of the drive wheel, slip reference value setting means for setting the slip reference value of the drive wheel, drive torque control means for controlling drive torque based on the detected drive slip state and the set slip reference value In the vehicular drive force control device having the apparatus, the slip reference value is changed in accordance with the change rate until the change rate of the drive slip state reaches a predetermined value, and the slip when the change rate of the drive slip state is equal to or greater than a predetermined value. A driving force control device for a vehicle, comprising slip reference value changing means for storing a reference value at an upper limit or a lower limit.