JPH01145236A - Drive power controller for vehicle - Google Patents

Abstract

PURPOSE:To permit the proper slip suppressing control independently of the variation of the tire diameter by installing a means for correcting the drive wheel speed or car body speed so that the drive wheel speed and the car body speed coincide when both speeds differ in the constant speed traveling state. CONSTITUTION:A drive wheel speed detecting means (a) for detecting the revolution speed of a drive wheel, car speed detecting means (b) for detecting the traveling speed of a vehicle, and a constant speed traveling state detecting means (c) for detecting the constant speed traveling state of the vehicle are installed. If the drive wheel speed and the car body speed differ, when the constant speed traveling state is detected, a speed correction calculating means (d) corrects the drive wheel speed or car speed so that both speed coincide. Then, an actual slip rate calculating means (e) calculates the actual slip rate between a tire and a road surface from the detected or corrected drive wheel speed and the car speed, and when the actual slip rate exceeds a prescribed set slip rate, a drive power controlling means (f) executes the drive power reduction control.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle driving force control device that suppresses slippage of drive wheels.

(Prior Art) As a conventional vehicle driving force control device, for example, a device described in Japanese Patent Application Laid-Open No. 60-43133 is known.

This conventional device is configured to forcibly close the throttle valve to reduce the driving force when the slip ratio is larger than a predetermined setting value when driving wheel slip occurs.

(Problem to be Solved by the Invention) However, in such a vehicle driving force control device, the slip rate between the tire and the road surface is uniquely calculated based on the drive wheel speed and the vehicle body speed obtained by detection. However, if the slip ratio exceeds a predetermined setting value, driving force reduction control is performed, so if the accurate wheel speed value cannot be detected due to a change in tire diameter, the slip ratio may be incorrectly determined. Therefore, due to the error in the slip ratio, the original driving force reduction control cannot be performed.

Incidentally, examples of cases in which the tire diameter changes include when the tire is replaced with a tire of a different diameter during driving, when the air pressure changes, when a chain is attached, or when a tire goes flat.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and to achieve this purpose, the present invention employs the following solving means.

The solving means of the present invention will be explained with reference to the claim correspondence diagram shown in FIG.
Then, the vehicle body speed detecting means detects the vehicle body speed, the constant speed traveling state detecting means C detects the constant speed traveling state of the vehicle, and the driving wheel speed and the vehicle body speed are detected even though the vehicle is traveling at a constant speed. a speed correction calculation means d which corrects the driving wheel speed or the vehicle body speed so that the speeds of one vehicle match if they are different, and obtains the corrected driving wheel speed or the corrected vehicle body speed; and the driving wheel speed obtained by the detection or correction. Actual lip ratio calculating means e that calculates the actual slip ratio between the tires and the road surface based on the vehicle speed, and a driving force reduction means to suppress the drive shaft slip when the surface actual slip ratio exceeds a predetermined set slip ratio. A driving force control means f for performing control is provided.

Note that the constant speed running state detection means C means that the accelerator pedal is
F, means for determining that the vehicle is running at a constant speed when the brake pedal is OFF, or means for determining that the vehicle is running at a constant speed when the clutch is disengaged or the gear is in the neutral position.

Further, the driving force control means f refers to a means capable of reducing the driving force, and specifically includes one of a throttle valve opening/closing control device, a fuel cut device 9, a simmer timing control device, a brake device, etc. It is a means that combines two or more.

(Function) When the driver changes the tire diameter to a tire with a different diameter, when the air pressure changes, when the driver attaches a chain, or when the tire diameter changes due to a puncture, etc., after the tire diameter changes, When a predetermined constant speed running state is achieved, based on the detection by the constant speed running state detection means C, the speed correction calculation means d determines that the driving wheel speed and the vehicle body speed are different even though the vehicle is running at a constant speed. In this case, the driving wheel speed or vehicle body speed is corrected so that both speeds match, and processing is performed to obtain the corrected driving wheel speed or corrected vehicle body speed.

Therefore, the actual slip ratio calculated by the actual slip ratio calculating means e is a calculated value based on an appropriate value corrected for the detection error of the driving wheel speed or vehicle speed due to a change in tire diameter. However, the original slip suppression control can be carried out smoothly.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a driving force control device applied during rear wheel drive will be taken as an example.

First, the configuration of the first embodiment will be explained.

As shown in FIG.
O, transmission 11, propeller shaft 12,
It has a rear differential of 13, a rear drive shaft of 14.15, and a rear wheel of 16.17.

Front wheels 18,19 are non-drive wheels.

The driving force control device A of the embodiment includes an accelerator pedal 20 which is an accelerator operator, and a throttle valve 22 provided in a throttle chamber 21 which is an intake system of the engine IO.
A control device is provided between the accelerator pedal 20 and the throttle valve 22 in place of a mechanical connection means such as an accelerator control wire, and the rear wheel rotation speed sensor 30 is used as an input sensor. Right front wheel rotation speed sensor 31, left front wheel rotation speed sensor 32, accelerator potentiometer 33, accelerator pedal full open switch 39. It includes a brake pedal full open switch 40, a throttle valve control circuit 34 as an arithmetic processing means, and a step motor 35 as a throttle actuator.

The rear wheel rotation speed sensor 30 is a drive wheel speed detection means,
It is provided at the input shaft portion of the rear differential 13 and outputs a rear wheel rotation signal (vr) according to the rear wheel rotation speeds V and l.

Note that a photosensitive sensor, a magnetic sensor, or the like is used as the rear wheel rotation speed sensor 30, and when a pulse signal is output as the rear wheel rotation signal (vr), an input interface in the throttle valve control circuit 34 is used. In circuit 341, F
The /V converter converts it into a voltage according to the frequency of the pulse signal, and the A/D converter converts the voltage value into a digital value, which is read into the CPU 342 and memory 343.

The right front wheel rotation speed sensor 31 and the left front wheel rotation speed sensor 3
Reference numeral 2 denotes a vehicle speed detecting means, which is provided at each axle portion of the front wheels 18 and 19, and is configured to detect the right front wheel rotation speed V'F.
R and left front wheel rotation speed V'rt.

It outputs a right front wheel rotation signal (vfr) and a left front wheel rotation signal (vfI2) according to the following.

Note that signal conversion for reading the output signals from both front axle rotation speed sensors 31 and 32 by the CPU 342 of the throttle valve control circuit 34 is performed in the same building as the rear wheel rotation speed sensor 30.

The accelerator potentiometer 33 is a means for detecting the absolute accelerator operation amount e, is provided at the position of the accelerator pedal 20, and outputs an absolute accelerator operation amount signal (β) corresponding to the absolute accelerator operation amount 2.

Note that since the output signal from the accelerator potentiometer 33 is an analog signal based on a voltage value, it is converted into a digital value by the A/D converter of the input interface circuit 341 and read into the CPU 342 and the memory 343.

The throttle valve control circuit 34 processes the human power information from the input sensor and the information temporarily or pre-stored in the memory 343 according to a predetermined arithmetic processing procedure, and controls the step motor 35 which is the throttle actuator.
An electronic circuit centered on a microcomputer that outputs a pulse control signal (C) to the input interface circuit 341. CPU (central processing unit) 342, memory (RAM).

ROM) 343 and an output interface circuit 344.

The step motor 35 is an actuator that opens and closes the throttle valve 22, and includes a single rotor and a plurality of stators having excitation windings, and rotates in the forward and reverse directions depending on how pulses are applied to the excitation windings. Rotate one step at a time.

Next, the operation of the first embodiment will be explained.

First, the flow of the throttle valve opening/closing control operation in the CPU 342 will be described with reference to the main routine flowchart shown in FIG. 3 and the subroutine flowchart shown in FIG. 4.

Note that the processing in the main routine of FIG.
This is a fixed time interrupt process that is started at 0m5ecl, and the process in the subroutine shown in FIG. oci(
This is an output conveyor (interconnected) interrupt process.

(B) Initial Settings The main routine shown in Figure 3 starts when the engine key is inserted into the key cylinder and the ignition switch is turned from OFF to ON. A determination is made (step 100), and the process proceeds to the next initialization step 101.

In this initialization step 101, all information set during the previous run is cleared.

(b) Slip ratio calculation processing First, based on the input signals from each rotation speed sensor 30, 31, 32, the rear wheel rotation speed V R and the right front wheel rotation speed V'□
, the left front wheel rotation speed V”FL is read (step 1
02).

In step 103, the accelerator pedal full open switch 39
It is determined whether the accelerator pedal is OFF (solution M) based on the switch signal from.

In step 104, the brake pedal fully closed switch 40
It is determined whether the brake pedal is OFF (released) or not based on the switch signal from the brake pedal.

Both steps 103 and 104 are steps for detecting whether or not the vehicle is running at a constant speed. If either or both of the one-car steps 103 and 104 is determined to be NO, the process advances to step 106, and both steps 103 and 104 are performed. If the determination is YES in either case (constant speed running state), the process proceeds to step 105.

In step 105, based on the rear wheel rotation speed vR,
The correction coefficient for the right front wheel rotation speed V'FR, and the correction coefficient for the left front wheel rotation speed V'FL! lk2 is obtained by calculation.

Note that the correction coefficients 2 and 2 are held until it is determined that the vehicle is running at a constant speed again. The calculation formula is as follows.

In step 106, a right front wheel rotational speed correction value V FR and a left front wheel rotational speed correction value V FL are calculated.

Note that the calculation formula is as follows.

VFR=kl*V”FR vFL=to2*v'FL However, the initial value is 2=1.

In step 107, the front wheel rotation speed VF is calculated using the right front wheel rotation speed correction value V□ and the left front wheel rotation speed correction value VFL.

The calculation formula for the front wheel rotational speed vF is: , and is determined by the average value.

Next, in step 108, the slip rate S is calculated.

be.

(c) Driving force control processing First, in step 109, the absolute accelerator operation amount e and the actual step number 5TEP used in the processing described later are read.

In step 110, the slip rate S is set to the set slip rate S.
. (for example, 0.1), and if S≦So and it is determined as No, the process proceeds to step 111 as a normal control pattern, and based on the absolute accelerator operation amount β read in step 109, Then, the target step number 5TEP* is calculated as a value shown in the characteristic line described in the step.

Further, if S>So and YES is determined in step 110, the process proceeds to step 112, and the target number of steps is 5 TEP* in order to perform slip suppression control to close the throttle valve 22 in the fully open direction as a slip suppression control pattern.
is set to zero. In step 113, the deviation ε is the actual step number 5TEP from the target step fisTEP*.
Based on the deviation ε obtained by this calculation, the motor speed of the step motor 35 is calculated, forward rotation, reverse rotation, and holding are determined, and the activation cycle of the oci interrupt routine is determined (step 114). ),
The oci interrupt routine (fourth
) is activated (step 115).

Next, a flowchart of the oci interrupt routine will be described with reference to FIG.

First, it is determined whether it is time to output a holding command to maintain the state of the step motor 35 (step 300).
), when the holding command is output, the step motor 3
The stator side excitation state of No. 5 is maintained (step 301).

In addition, when the holding command is not output, the step motor 3
It is determined whether or not it is time to output a reversal command to reverse the rotation speed (step 302), and when the reversal command is output, 5TEP should be set to 5TEP-1 (step 303).
) and 5TEP-1 are output to the step motor 35 (step 301). Furthermore, when outputting a normal rotation command to rotate the step motor 35 in the normal direction, 5TE
Set P to 5TEP+1 (step 304), s"
The pulse signal that provides rEp+1 is sent to the step motor 35.
(Step 301).

Note that this oci interrupt routine is performed in step 11 above.
It is repeated within the main routine startup cycle according to the startup cycle set in step 7.

Next, the effect during driving will be described.

As a result of the above-described control processing operation, when the slip ratio is S≦30 and no drive wheel slip occurs during driving, from step 110 to step Ill → step 113
The flow of the normal control pattern proceeds to
is controlled to open and close.

In addition, when the slip rate is S>So and drive wheel slip occurs, such as when starting, accelerating, or driving on a road with a low friction coefficient, the slip control proceeds from step 110 to step 112 → step 113. This is the flow of the control pattern, and driving wheel slip is suppressed by closing the throttle valve 22.

In this way, the slip suppression control is started and the control is canceled based on the slip rate S and the set slip rate S determined by calculation.

Miscalculation of the slip rate S cannot be tolerated in order to carry out the original slip suppression control based on any size comparison.

Therefore, a case where the tire diameter changes which causes an erroneous calculation of the slip ratio S will be described.

If the tire diameter changes due to the driver changing the tire to a different tire diameter, changing the air pressure, attaching a chain, or having a flat tire, the accelerator pedal and brake When the constant speed running state is realized with the OFF operation of the pedal, step 103-
Step 104→Proceed to step 105, and step 1
In 05, the correction coefficient k r of the right front wheel rotation speed V'□ and the left front wheel rotation speed V'FL obtained by detection based on the rear wheel rotation speed vR, which is the drive wheel speed.

k2 is calculated, and in the next step 106, the right front wheel rotational speed correction value VFR and the right front wheel rotational speed correction value VFL are calculated.

Therefore, the slip ratio S calculated in step lO8 is a calculated value based on an appropriate value that corrects the detection error of the front wheel rotational speed due to a change in tire diameter, and even if there is a change in tire diameter, the original slip suppression control can be carried out smoothly.

Next, a second embodiment of the apparatus shown in FIGS. 5 and 6 will be described.

This second embodiment device is provided with a clutch disengagement switch 41 and a gear position switch 42 (FIG. 5) as means for obtaining judgment information for detecting a constant speed running state, and when the clutch is disengaged in step 116. Alternatively, when the gear position is at the neutral gear position in step 117, it is determined that the vehicle is in a constant speed running state, and the process proceeds to step 105 (FIG. 6).

Note that the other configurations and operations are the same as those in the first embodiment, so their explanations will be omitted here.

Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment. include.

For example, in the embodiment, a throttle valve opening/closing control device was shown as the driving force control means, but it is also possible to use a fuel cut device, adjust the ignition opening to reduce the engine output, or use the brakes to reduce the engine output. The driving force may be reduced by other means, such as applying a braking force to the vehicle, or by a combination of means.

Further, as the throttle opening/closing control, a device that suppresses slip by map drop control may be used, as described in the specification of Japanese Patent Application No. 157389/1989, which was previously filed by the present applicant. ,X.

(Effects of the Invention) As described above, the heavy vehicle driving force control device of the present invention includes a driving wheel speed detecting means for detecting the driving wheel speed, a vehicle body speed detecting means for detecting the vehicle body speed, A constant speed driving state detecting means detects a constant speed driving state of the vehicle.If the driving wheel speed and the vehicle body speed are different even though the vehicle is traveling at a constant speed, the driving wheel speed or the vehicle body speed is adjusted to match the driving wheel speed or A speed correction calculation means for correcting the vehicle speed to obtain a corrected driving wheel speed or a corrected vehicle body speed, and an actual slip ratio between the tires and the road surface based on the driving wheel speed and the vehicle speed obtained by the detection or correction. The invention is characterized by comprising: a large slip ratio calculating means; and a driving force control means for suppressing drive wheel slip (driving force reduction control) when the actual slip ratio exceeds a predetermined set slip ratio. This means that if the driver replaces a tire with a different tire diameter, changes the air pressure, attaches a chain, or has a flat tire, etc.
Even when the tire diameter changes, the calculated value is based on an appropriate value with wheel speed detection errors corrected, and even when the tire diameter changes, the original slip suppression control can be performed smoothly.

[Brief explanation of the drawing]

Fig. 1 is a claim-corresponding diagram showing the vehicle driving force control device of the present invention, Fig. 2 is an overall view showing the driving force control device of the first embodiment of the present invention, and Fig. 3 is a throttle valve of the first embodiment. FIG. 4 is a flowchart showing a main routine of control operation in the control circuit; FIG. 4 is a flowchart showing a subroutine of control operation in the throttle valve 111J 1N circuit of the embodiment;
FIG. 5 is an overall view showing the driving force control device of the second embodiment, and FIG. 6 is a flowchart showing part of the main routine of the control operation in the throttle valve control circuit of the second embodiment. a--Drive wheel speed detection means b--Vehicle speed detection means C--Constant speed running state detection means d--Speed correction calculation means e--Actual lip ratio calculation means r--Drive force control means

Claims (1)

[Scope of Claims] 1) Drive wheel speed detection means for detecting drive wheel speed; vehicle speed detection means for detecting vehicle speed; constant speed running state detection means for detecting constant speed running state of the vehicle; If the driving wheel speed and vehicle body speed are different even though the vehicle is running at high speed, the driving wheel speed or vehicle body speed is corrected so that both speeds match, and the speed is corrected to the corrected driving wheel speed or corrected vehicle body speed. a calculation means; an actual slip ratio calculation means for calculating an actual slip ratio between the tire and the road surface based on the drive wheel speed and vehicle body speed obtained by the detection or correction; and when the actual slip ratio exceeds a predetermined set slip ratio. 1. A driving force control device for a vehicle, comprising: a driving force control means that performs driving force reduction control to suppress drive wheel slip when the drive wheel slips.