JPH01145232A - Differential limit controller for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a differential limiting control device for a vehicle that is used in a differential device of an automobile and controls differential limiting torque.

(Prior Art) Conventional differential limiting control devices for vehicles include, for example, Japanese Patent Laid-Open No. 103227/1983 (Patent Application No. 244677/1983) and Japanese Patent Laid-open No. 102320/1983 (Patent Application No. 223/1989).
486) is known.

The former conventional device is a differential limiting control device for a vehicle that can control differential limiting torque, and in order to reliably control even in a sudden one-wheel slip situation, the differential limiting torque characteristic for the left and right drive wheel rotational speed difference is controlled. It has progressive characteristics.

The latter conventional device is a vehicle differential limiting control device that can control differential limiting torque, and uses large steering, large accelerator opening, and road surface μ below a predetermined vehicle speed to prevent the inner wheels from sticking when turning. When is high, the differential limiting torque is reduced.

(Problem to be solved by the invention) However, in the conventional fore-and-back device, the differential limiting torque is generated in proportion to the rotational speed difference between the left and right drive wheels, so there is only slight inner wheel spin when turning. If there is no large difference in rotational speed between the left and right drive wheels, the differential limiting torque is also small, leaving the problem that it is difficult for the driver to apply a power drift.

In addition, because the latter conventional device was configured to generate differential limiting torque in proportion to the accelerator opening, one wheel could slip on a split μ road (a road surface with different road surface friction coefficients for the left and right axles). If the accelerator opening is small, such as when the inner wheel spins when turning, high differential limiting torque will not be generated, and high driving force will be applied to the high μ road side or the outer wheel side while sufficiently suppressing wheel spin. The problem remained that it was not possible to convey the information.

(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 solution of the present invention will be explained with reference to the conceptual diagram of the claims shown in FIG. A differential limiting control device for a vehicle is provided with a clutch control means 3 that performs increase/decrease control of differential limiting torque based on a detection signal of the accelerator opening detection means 201 and left and right drive wheels as the detection means 2 and a rotational speed difference detection means 202, and the clutch control means 3
The final differential limiting torque command value is the sum of the differential limiting torque command value, which increases in proportion to the accelerator opening, and the differential limiting torque command value, which increases in proportion to the left and right drive wheel rotational speed difference. characterized by things.

(Function) If one wheel slips on a split μ road or the inner wheel spins when turning, operating the accelerator in the direction of depression will increase the slip and spin, so generally reduce the accelerator opening.

However, the final differential limiting torque command value is determined in the clutch control means 3 by combining the differential limiting torque command value with the left and right drive wheel rotational speed difference as a parameter and the differential limiting torque command value with the accelerator opening degree as a parameter. Since it is determined by the sum, the final differential limiting torque command value is determined based on the differential limiting torque command value based on the rotational speed difference between the left and right driving wheels, regardless of the accelerator opening degree.

During power drift driving, the driver depresses the accelerator and uses the skidding of the drive wheels to turn the vehicle.Since this is done when driving on roads with a high friction coefficient, the difference in rotational speed between the left and right drive wheels is small by 1/X.

However, the final differential limiting torque command value is determined in the clutch control means 3 by combining the differential limiting torque command value with the left and right drive wheel rotational speed difference as a parameter and the differential limiting torque command value with the accelerator opening degree as a parameter. Since it is determined by the sum, the final differential limiting torque command value is determined based on the differential limiting torque command value based on the accelerator opening, regardless of the rotational speed difference between the left and right driving wheels.

Therefore, the final differential limiting torque command value is determined by the sum of the differential limiting torque command value of the left and right drive wheel rotational speed difference and the accelerator opening, that is, the two control elements are highly compatible with each other. Therefore, it is possible to achieve both suppression of slip on a split μ road, suppression of inner wheel spin during turning, and ease of power drift.

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

In describing this embodiment, a differential limiting control device for a rear wheel drive vehicle equipped with a multi-disc friction clutch means operated by external hydraulic pressure will be taken as an example.

First, the configuration of the embodiment will be explained.

As shown in FIG. 2, the rear-wheel drive vehicle to which the differential limiting control device of the embodiment is applied includes a left front wheel lO1, a right front wheel 11, an engine 12. Transmission 13, professional shaft 14, differential 15, left drive shaft 16, right drive shirt)-17, left rear wheel 18, right rear wheel 19
The differential device 15 includes a propeller shaft 14 on the drive input side and a drive shaft l on the drive output side.
6.17, a wet multi-plate friction clutch (differential limiting clutch means) 20 is provided to limit the differential movement of the left and right shafts 18, 19.

Note that the wet multi-disc clutch 20 is engaged by control hydraulic pressure P from a hydraulic pressure generator 30, which is an external device.

As shown in FIG. 3, the differential limiting control device of the embodiment is as follows.
A left rear wheel rotation speed sensor 43, a right rear wheel rotation speed sensor 44, and an accelerator opening sensor 45 are provided as input sensors 40, and a differential limiting control circuit 50 is provided as a control module.
is provided, and an electromagnetic proportional pressure reducing valve 60 is provided as a control actuator.

The left rear wheel rotational speed sensor 43 and the right rear wheel rotational speed sensor 4 are means for detecting the rotational speed of the left and right rear wheels 18°19, which are drive wheels, and the sensor 43 detects the left rear wheel rotational speed N°. The sensor 44 outputs a left rear wheel rotational speed signal (nrl) corresponding to the right rear wheel rotational speed NRR, and a right rear wheel rotational speed signal (nrr) corresponding to the right rear wheel rotational speed NRR.

The accelerator opening sensor 45 is a sensor that outputs an accelerator opening signal (a) corresponding to the accelerator opening A.

The differential limiting control circuit 50 is a control circuit mainly based on an on-vehicle microcomputer, and includes an input interface circuit 51, a memory 52, a CPU (central processing unit) 53. An output interface circuit 54 is provided.

The memory 52 of the differential limit control circuit 50 stores the differential limit torque ΔT, (
The calculation formula for the control oil pressure PM) (torque characteristics shown in Figure 4) and the calculation formula for the differential limiting torque ΔTA (control oil pressure PA) with respect to the accelerator opening degree A (torque characteristics shown in Figure 5) are set in advance. There is.

The electromagnetic proportional pressure reducing valve 6o is connected to the hydraulic pressure generator 30.
The hydraulic oil at the pump pressure supplied from the hydraulic pump 31 via the pump pressure oil path 32 is controlled by the control current signal (i) from the differential limiting control circuit 50 to the magnitude of one command current value. This is a valve actuator that controls pressure to a control oil pressure P proportional to .

In addition, the control oil pressure P and the differential limiting torque T are TccP-u
-n-r·E n: Number of clutches r: Clutch average radius E: Pressure-receiving area, and the differential limiting torque T is proportional to the control oil pressure P.

Next, the operation of the embodiment will be explained.

First, the operational flow of the differential limiting control in the differential limiting control circuit 50 will be described with reference to the flowchart shown in FIG.

In the step 100, the left rear wheel rotation speed NRL, the right rear wheel rotation speed NRR, and the accelerator opening degree A are read based on the signals from the sensors 43, 44, and 45.

In step 101, the left and right drive wheel rotational speed difference ΔNrJ2 is calculated from the left rear wheel rotational speed NRL and the right rear wheel rotational speed NRR read in step 100.

The calculation formula is ΔN r 12 = NRL - NRR
It is.

In step 102, a differential limiting torque T8 proportional to the left and right drive wheel rotational speed difference ΔNrI2 obtained in step 101 is determined.

As shown in the characteristic diagram of FIG. 4, this differential limiting torque T is obtained as a value that is linearly proportional to the increase in Nrβ to the rotational speed difference between the left and right driving wheels.

In step 103, differential limiting torque TA is determined which is proportional to the accelerator opening degree A read in step loo.

The differential limiting torque TA is obtained as a value that is linearly proportional to the increase in the accelerator opening A, as shown in the characteristic diagram of FIG.

In step 104, each of the differential limiting torques T, , TA
The final differential limiting torque T is calculated from .

The calculation formula for the final differential limiting torque T is as shown below.

T == T N + T A In step 105, a signal (i) based on one command current value from which the final differential limiting torque T is obtained is output.

Next, the effects during driving will be explained separately for when one wheel slips (including when the inner wheel spins when turning) and when driving with power drift.

(B) Split when one wheel slips If one wheel slips on a μ road or the inner wheel spins when turning, operating the accelerator in the direction of depression will increase the slip and spin, so generally reduce the accelerator opening A. do.

However, the final differential limiting torque T is the differential limiting torque TN with the left and right driving wheel rotational speed difference ΔNr (l as a parameter) and the differential limiting torque T with the accelerator opening degree A as a parameter.
Since it is determined by the sum of A and A, the final differential limiting torque T is determined based on the differential limiting torque Ts based on the left and right driving wheel rotational speed difference ΔNrI2, regardless of the accelerator opening degree A.

Therefore, when one wheel slips on a split μ road, the high differential limiting torque T suppresses the slip of the wheel on the low μ road side, while distributing the engine driving force to the high μ road side. If the inner wheel spins during a turn, the high differential limiting torque T suppresses the inner wheel spin, and the grip on the road surface due to the contact between the inner and outer wheels improves the cornering ability.

(b) When driving with power drift When driving with power drift, the driver depresses the accelerator and turns using the sideslip of the drive wheels18. The rotational speed difference ΔNrJ2 is small.

However, the final differential limiting torque T is the differential limiting torque TN with the left and right driving wheel rotational speed difference ΔNrI2 as a parameter, and the differential limiting torque T with the accelerator opening degree A as a parameter.
Since it is determined by the sum of A, the left and right drive wheel rotational speed difference △
The final differential limiting torque T is determined based on the differential limiting torque TA based on the accelerator opening degree A, regardless of Nrβ.

Therefore, the differential limiting torque T corresponding to the accelerator work can be obtained, and the power drift can be easily performed while controlling the drift by depressing the accelerator.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may include design variations within the scope of the invention. included.

For example, in the embodiment, as an actuator.

Although an electromagnetic proportional pressure reducing valve is shown, an example in which an electromagnetic valve that opens and closes or the like may be used to perform hydraulic control by using a control signal as a duty signal may also be used.

Further, in the embodiment, an example was shown in which the differential limiting torque is obtained using a wet multi-disc friction clutch, but an example in which the differential limiting torque is obtained using a clutch such as an electromagnetic clutch or a brake may also be used.

(Effects of the Invention) As explained above, in the small-duty differential limiting control device of the present invention, the clutch control means controls the differential limiting torque command value that increases in proportion to the accelerator opening, and the left and right differential limiting torque command values that increase in proportion to the accelerator opening. The final differential limiting torque command value is the sum of the differential limiting torque command value, which increases in proportion to the drive wheel rotational speed difference.
The final differential limiting torque command value is determined with high compatibility between the two control elements, the difference in rotational speed of the left and right drive wheels and the degree of accelerator opening, to suppress slips on split μ roads and to control inner wheels when turning. The effect of achieving both spin suppression and ease of power drift can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a claim showing a differential limiting control device for a vehicle of the present invention, Fig. 2 is an overall view of an embodiment of the device of the present invention, and Fig. 3 is a differential limiting control including a hydraulic pressure generating device of an embodiment. A diagram showing the device, FIG. 4 is a differential limiting torque characteristic diagram with respect to the rotational speed difference between left and right drive wheels set in the differential limiting control circuit of the embodiment, and FIG. 5 is a diagram showing the differential limiting torque characteristic set in the differential limiting control circuit of the embodiment. FIG. 6 is a flowchart showing the flow of the differential limiting control operation in the embodiment device. l-...Differential limiting clutch means 2...Detection means 201...-Accelerator opening detection means 202...-Left and right drive wheel rotational speed difference detection means 3...-Clutch control means

Claims (1)

[Claims] 1) A differential limiting clutch means provided between the left and right drive wheels and engaged by an external control force, and an increase/decrease in the differential limiting torque based on a detection signal from a predetermined detection means. A differential limiting control device for a vehicle is provided with a clutch control means for performing control, wherein the detection means includes an accelerator opening degree detection means and a left and right drive wheel rotational speed difference detection means, and the clutch control means includes: The final differential limiting torque command value is the sum of the differential limiting torque command value, which increases in proportion to the accelerator opening, and the differential limiting torque command value, which increases in proportion to the left and right drive wheel rotational speed difference. Characteristic differential limiting control device for vehicles.