JPH06167230A - Driving force controller for vehicle - Google Patents

Abstract

PURPOSE:To always and surely realize operatability such as acceleration intended by a driver by correcting a slipping standard value of driving wheels to which drivig torque of an engine is transmitted via a transmission, by a larger correction value as a shift position detected by the transmission moves closer to the low-speed stage side. CONSTITUTION:Rotational speeds of respective driving wheels 2(L, R) in a vehicle are detected by respective wheel rotational speed sensors 6, 7, and these respective detection signals are inputted to the CPU 11 of a driving force control unit 8, and slipping conditions of the respective driving wheels 2L, 2R are detected. A slipping standard value of driving torque control of driving wheels 2 is set based on the detection signal of an accelerator opening sensor 14 by means of CPU 11. The driving torque of the engine is controlled via a fuel supply control unit 12 of respective cylinders 13-1-13-6, in response to the detection value and the standard value of the slipping, by utilizing the accelerator operation quantity and speed change shift position as parameters which display acceleration intention of a driver. In this case, the shift position of the transmission for transmitting the driving torque of the engine to the driving wheels 2L, 2R is detected. As a result, the standard value of the slipping is corrected by a larger correction quantity as the speed change ratio at the detected shift position is shifted closer to the low speed stage side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular driving force control device for realizing a drivability intended by a driver.

[0002]

2. Description of the Related Art As a conventional example of a vehicle drive control device for performing drive torque control, which controls variablely the drive torque supplied to the drive wheel in accordance with the drive slip state when a drive slip occurs in the drive wheel, For example, JP-A-63-3183
There is one disclosed in Japanese Patent No. 0. In this conventional example, by using the accelerator operation amount (the throttle opening is substituted) as a parameter, the engine drive torque is variably controlled so that the drive slip state becomes the slip target value (reference value), The drive slip is eliminated. At that time, the accelerator operation amount is used as a parameter indicating the driver's intention to accelerate, and the slip target value is increased as the absolute value of the accelerator operation amount is increased so that the drivability intended by the driver is realized. Therefore, for example, it is possible to suppress the drive slip to a low level during turning, maintain the stability of the vehicle, and realize the acceleration required by the driver when exiting a corner.

[0003]

However, in the above-mentioned conventional vehicle drive force control device, even if the accelerator operation amount is the same, the driver's willingness to accelerate varies depending on the shift position of the transmission. Since the driver's willingness to accelerate is judged only by the accelerator operation amount without consideration, for example, the driver's willingness to accelerate becomes stronger as the shift position is closer to the low speed side (low gear side). This is not reflected in the drive torque control, and eventually the drivability intended by the driver cannot be always realized. That is, when the driving force is not controlled, strong acceleration can be obtained even at the same accelerator opening as on the low gear side, but when the driving force is controlled, the slip state of the wheels is the same regardless of the shift position, which causes a strange feeling. .

According to the present invention, when the driver's intention of acceleration is reflected in the slip reference value of the drive torque control, the accelerator operation amount and the shift position of the transmission are used as parameters indicating the driver's intention of acceleration. , The goal is to always achieve the drivability intended by the driver.

[0005]

To this end, the structure of claim 1 of the vehicular driving force control apparatus of the present invention is, as the concept is shown in FIG. 1, through a transmission by a driving torque from an engine. Drive slip detection means for detecting a drive slip state of the driven drive wheel, accelerator operation state detection means for detecting an accelerator operation state, and the drive wheel according to the accelerator operation amount detected by the accelerator operation state detection means. In the vehicle drive force control device, the slip reference value setting means for setting the slip reference value of, and the drive torque control means for performing the drive torque control based on the detected drive slip state and the set slip reference value, The shift position detecting means for detecting the shift position of the transmission and the gear ratio at the shift position detected by the shift position detecting means are on the low speed stage side. Further, a slip reference value correcting means for correcting the slip reference value with a large correction amount is provided, and the slip reference value is corrected by the slip reference value correcting means as described in claim 2, for example. When the accelerator operation amount is equal to or greater than a predetermined value, correction is performed to increase the slip reference value with a predetermined gain, and one or both of correction for lowering the predetermined value as the shift position becomes lower and correction for increasing the predetermined gain. Shall be performed.

[0006]

In the vehicle driving force control device of the present invention, based on the drive slip state of the drive wheels detected by the drive slip detection means and the slip reference value set by the slip reference value setting means according to the accelerator operation amount, The drive torque control means performs drive torque control. At this time, the slip reference value correction means corrects the slip reference value with a larger correction amount as the gear ratio at the shift position of the transmission detected by the shift position detection means becomes lower. This correction is
For example, as in claim 2, a correction for increasing the slip reference value by a predetermined gain when the accelerator operation amount is equal to or greater than a predetermined value, and a correction and a predetermined gain for lowering the predetermined value as the shift position decreases. The correction is performed in combination with one or both of the increasing corrections. As a result, for example, a situation in which the driver has a strong intention to accelerate when the shift position is on the low speed side (low gear side) is reflected in the drive torque control, and the drivability intended by the driver is always realized. It gives a natural driving feeling.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows the first embodiment of the vehicle driving force control device of the present invention.
It is a figure which shows the structure of an Example, 1L, 1R shows a left front wheel, a right front wheel, 2L, 2R shows a left rear wheel, a right rear wheel, 3 shows an engine. This vehicle is configured as a rear wheel drive vehicle in which rear wheels 2L and 2R that are drive wheels are driven by an engine 3, and wheel rotation sensors 4, 5 and 6 are provided in the vicinity of the wheels 1L, 1R, 2L and 2R, respectively. , 7 are provided (the vehicle may be an all-wheel drive vehicle).

The wheel rotation sensors 4 to 7 detect the rotation speed of each wheel as a pulse signal having a frequency corresponding to the rotation speed. The obtained rotation speeds VFL, VFR,
A pulse signal having a frequency corresponding to VRL and VRR is input to the F / V converter 9 of the driving force control unit 8. The driving force control section 8 comprises an F / V converter 9, an A / D converter 10 and a CPU 11, and the F / V converter 9
Converts the input signal from each of the wheel sensors 4 to 7 and inputs the voltage to the A / D converter 10. The A / D converter 10 digitally converts each input signal and inputs the digital signal to the CPU 11.
Note that the CPU 11 uses, for example, a microcomputer.

In this example, an accelerator opening sensor 14 is provided as an accelerator operation detecting means for detecting an accelerator operation state (accelerator operation amount), and an accelerator opening signal L which is an output signal thereof is input to the A / D converter 10. In addition, an engine speed sensor 15 for detecting the engine speed is provided,
The engine speed signal Ne which is the output signal is input to the A / D converter 10.

The CPU 11 controls the wheel rotation speeds (wheel speeds) VFL, VFR, VRL, VRR, accelerator opening (operation amount) L and engine rotation speed Ne and the control programs shown in FIGS. Is executed to variably control the slip reference value used when executing the drive torque control according to the accelerator operation amount and the transmission shift position. In addition,
This first embodiment is premised on the engine control system in which the torque applied to the drive wheels is adjusted by adjusting the drive torque itself of the engine, and the CPU 11 outputs the fuel supply cut signal FC to the fuel supply control unit 12. Then, by this signal FC, the fuel supply control unit
The injection pulse IP output from 12 to each of the cylinders 13-1 to 13-6 of the engine is cut off to execute the fuel cut.

The operation system (not shown) is repeatedly executed by a periodic interrupt every predetermined period.
In the control program, first, in step 101, the rotational speeds VFL and VFR of the left and right front wheels, which are driven wheels, and the rotational speeds VRL and VRR of the left and right rear wheels, which are 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 wheels (driven wheels) is VF = (VFL +
VFR) / 2 to calculate the driven wheel speed, and then step 10
In the case of 3, the average rotational speed VR of the rear wheels (driving wheels) is VR = (VR
L + VRR) / 2 to obtain the drive wheel speed, and in step 104 the drive slip amount S is calculated by S = VR-VF. In the control program of FIG. 3, CP
U11 functions as a drive slip detecting means.

FIG. 4, performed after step 104,
In step 111 of the control program, the torque down instruction amount TD determined as described later in detail is read. In the next step 112, the torque down instruction amount TD
Whether or not is 0 is determined. If this determination is YES, that is, if the torque down instruction amount TD is 0 and the drive torque control is not being performed, it is determined that the control is completed, and in step 113, the accelerator operation amount L from the accelerator operation amount sensor 14
Is read, and in step 114 the reference value L ₀ of the accelerator operation amount is read.
Is updated to L. If the determination is NO, that is, if the torque down instruction amount TD is not 0 and drive torque control is being performed, the above steps 112 and 113 are performed.
Since the reference value L ₀ of the accelerator operation amount is not updated, the reference value L ₀ of the accelerator operation amount is held at the value before the start of the drive torque control.

FIG. 5, which is executed after step 114.
In steps 121 and 122 of the control program of
The current accelerator operation amount L and its reference value L ₀ obtained as described above are read. And the next step 123
Then, the accelerator depression amount ΔL is calculated as ΔL = L−L ₀ as a difference between the current accelerator operation amount and its reference value. In the control programs of FIGS. 4 and 5,
The CPU 11 functions as accelerator operation state detecting means.

FIG. 6, which is executed after step 123.
In step 131 of the control program, the engine speed Ne is read from the engine speed sensor 15. In the next step 132, the drive wheel speed VR calculated in step 103 is read (VR = (VRL + VRR) / 2). Then, in the next step 133, the gear ratio (gear ratio) i is changed to i = N
e / VR and step by the gear ratio i
At 134, the shift position SFT after shifting is estimated. In the control program of FIG. 6, the CPU 11 functions as shift position detecting means.

FIG. 7, which is executed after step 134.
In steps 141 and 142 of the control program of
The current accelerator depression amount Δ determined as described above
Read L and shift position SFT.

In the next step 143, the slip reference value S
The correction amount ΔS * of * is determined by looking up the map shown in step 143 of FIG. 7 with the shift position SFT. The map shown is prepared for each shift position SFT, and basically, the accelerator pedal depression amount Δ
When L is equal to or less than a predetermined value, a dead zone is provided in order to suppress the slip due to a rough accelerator operation by the driver and maintain the stability of the vehicle. When the accelerator depression amount ΔL is within the dead zone, the correction amount is set to 0. On the other hand, when the accelerator depression amount ΔL exceeds the predetermined value, it is considered that the driver has a strong intention to accelerate, and the slip target value S * is increased. At that time, it is estimated that the demand for acceleration is larger as the shift position SFT is closer to the low speed stage (lower gear side), and the dead zone is narrowed and the gain of the increase correction is set larger. In the control program of FIG. 7, the CPU 11 functions as a slip reference value correction means.

FIG. 8 executed after step 143.
In step 151 of the control program of 1., the driven wheel speed VF calculated in step 102 is read (VF = (V
FL + VFR) / 2). And in the next step 152,
Based on this VF, the initial value S * ₀ of the slip reference value is determined by looking up the map also shown in step 152 of FIG. In step 153, the previously calculated slip reference value correction amount ΔS * is read, and in step 154, the slip reference value S * is set to S * = S * ₀ + ΔS *.
Calculate by In the control program of FIG. 8, the CPU 11 functions as slip reference value setting means.

In step 161 of the control program of FIG. 9, which is executed after step 154 of the control program of FIG. 8, the current drive slip amount S is read and
In step 162, the slip reference value S * previously obtained is read, and in step 163 the two are compared. If S> S * is YES, the routine proceeds to step 164, where it is judged whether or not the torque down instruction amount TD is the maximum value TDmax. If S ≦ S * is NO, then the routine proceeds to step 165 and the torque down instruction amount TD is reached. Whether or not is 0 is determined.

The judgments at steps 164 and 165 become NO when TD takes a value between the upper limit value and the lower limit value. In that case, therefore, at the next steps 166 and 167, respectively, T
The D is incremented (TD = TD + 1) and decremented (TD = TD-1). In the case of YES, since the upper limit value or the lower limit value has already been reached and incrementing and decrementing are impossible, respectively, step 16
Skip 6 and 167. Then, in step 168, the CPU 11 outputs the fuel supply cut signal FC corresponding to the torque down instruction amount TD to the fuel supply control unit 12. In the control program of FIG. 9, the CPU 11 functions as a drive torque control means.

In the first embodiment, as described above, the accelerator operation amount (accelerator depression amount ΔL) and the shift position SFT of the transmission are used as parameters indicating the driver's intention to accelerate. The drive torque control reflects the driver's willingness to accelerate,
The drivability intended by the driver is realized and a desired driving feeling is obtained.

FIG. 10 is a flow chart showing the control program of the essential parts of the second embodiment of the vehicle driving force control apparatus of the present invention. The second embodiment has the same configuration as that of the first embodiment except that the control program of FIG. 10 is used instead of the control program of FIG. 5 of the first embodiment. In the control program of FIG. 10, which is executed after step 114 of the control program of FIG.
Then, the current accelerator operation amount L and the reference value L ₀ thereof, which are obtained as described above, are read, and the next step 173
To compare the two.

In this comparison, if L ≦ L ₀ NO,
Since it is necessary to update the current accelerator operation amount reference value L ₀ , in the next step 174, the accelerator operation amount reference value L _{0 is set.}
Is updated to the current accelerator operation amount L. On the other hand, if L> L ₀ is YES in the above comparison, the current accelerator operation amount L exceeds the accelerator operation amount reference value L ₀ and there is no need to update the accelerator operation amount reference value.
Skip step 4 and pass control immediately to step 175.
In step 175, the accelerator pedal depression amount ΔL is taken as the difference between the current accelerator operation amount and its reference value ΔL = L−
Calculate with L ₀ . In the control program shown in FIG. 10, the CPU 11 functions as accelerator operation state detecting means.

In the second embodiment, the minimum accelerator operation amount during execution of the drive torque control is stored as the accelerator operation amount reference value by executing the control program shown in FIG. The closer to the side (the lower gear side), the stronger the driver's willingness to accelerate is reflected in the drive torque control, and the same effect as in the first embodiment can be obtained.

In each of the above embodiments, the shift position (gear stage) SFT and the gear ratio (gear ratio) i are 1: 1.
Although it is assumed that the corresponding manual transmission will be applied, it can be applied to an automatic transmission. In that case, the shift position SF
The map search in step 143 may be performed by replacing T with the gear ratio i. Further, in each of the above embodiments, the drive torque control by cutting the fuel supply is adopted as the traction control, but the invention is not limited to this. For example, the throttle opening control for electrically controlling the throttle valve of the engine Alternatively, engine ignition timing control or brake control that directly applies pressure to the wheel cylinders may be used.

[0025]

As described above, the vehicle drive force control apparatus of the present invention uses the driver's intention of acceleration as a parameter for reflecting the driver's intention of acceleration in the slip reference value of the drive torque control. Since the accelerator operation amount and the shift position of the transmission are used, the slip reference value is corrected by a larger correction amount as the gear ratio at the shift position of the transmission is closer to the low speed stage. The situation in which the driver's intention to accelerate to the side (low gear side) is strong is reflected in the drive torque control, so that the drivability intended by the driver is always realized, and a natural driving feeling is obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the present invention.

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

FIG. 3 is a flowchart showing a control program for driving slip amount calculation in the same example.

FIG. 4 is a flowchart showing a control program for updating a reference value of an accelerator operation amount in the same example.

FIG. 5 is a flowchart showing a control program for calculating an accelerator depression amount in the same example.

FIG. 6 is a flowchart showing a control program for estimating a shift position after shifting in the same example.

FIG. 7 is a flowchart showing a control program for determining a slip reference value correction amount in the same example.

FIG. 8 is a flowchart showing a control program for setting a slip reference value in the same example.

FIG. 9 is a flowchart showing a control program for drive torque control in the same example.

FIG. 10 is a flowchart showing a control program of a main part of the second embodiment of the vehicle driving force control device of the invention.

[Explanation of symbols]

 1L, 1R Front wheel (driven wheel) 2L, 2R Rear wheel (driving wheel) 3 Engine 4-7 Wheel rotation sensor 11 CPU 12 Fuel supply control unit 13-1-13-6 Cylinder 14 Accelerator opening sensor 15 Engine rotation sensor

Claims (2)

[Claims] 1. A drive slip detection means for detecting a drive slip state of a drive wheel driven through a transmission by a drive torque from an engine, an accelerator operation state detection means for detecting an accelerator operation state, and the accelerator. Slip reference value setting means for setting a slip reference value of the drive wheel according to the accelerator operation amount detected by the operation state detection means, and drive torque for performing drive torque control based on the detected drive slip state and the set slip reference value. In a vehicle driving force control device including a control means, a shift position detecting means for detecting a shift position of the transmission, and a gear ratio at a shift position detected by the shift position detecting means becomes lower as a shift speed becomes lower. A vehicle equipped with a slip reference value correcting means for correcting the slip reference value with a large correction amount. Use the driving force control device. 2. The slip reference value correcting means performs a correction of increasing the slip reference value by a predetermined gain when the accelerator operation amount is a predetermined value or more when performing the correction, and the shift position is 2. One or both of a correction for lowering the predetermined value and a correction for increasing the predetermined gain are performed as the value becomes lower.
The vehicle driving force control device described.