JPH05256324A - Clutch control method - Google Patents

Abstract

PURPOSE:To reduce oscillation and improve safety by selecting a target clutch pressure corresponding to a creep rate based on an operation mode by means of an electronic control means, and thereby controlling a transmission torque of the clutch. CONSTITUTION:A clutch pressure of an oil passage 64 is adjusted by a clutch pressure control valve 52 which is controlled through an output pressure of a three-directional solenoid valve 58, and fed back as a clutch pressure 202 inside an electronic control part 98 by means of a hydraulic pressure sensor 68. In respect to determination of a target clutch pressure by means of the electronic control part 98, the target clutch pressure is set through computation of other target clutch pressure in case that it is not in a hold mode. In case that it is in the hold mode and fast idling, a map for lower creep is selected so as to obtain a lower value, and the target clutch pressure corresponding to the present engine speed. In case that it is not in first idling, the clutch pressure is determined based on a map for a normal creep. Controlling is thus performed with a normal creep rate, so that oscillations of a vehicle at the time of braking are reduced, and safety is improved since a normal operation is necessitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an automatic starting clutch for a vehicle such as an automobile.

[0002]

2. Description of the Related Art In a vehicle such as an automobile, a starting clutch is interposed between an internal combustion engine (engine) and driving wheels so that the degree of mechanical coupling between the internal combustion engine and the driving wheels is continuous or discontinuous. By continuously changing the speed, the vehicle accelerates or decelerates continuously when the vehicle starts or stops, and runs at a low speed equal to or lower than the vehicle speed corresponding to the minimum operating speed of the internal combustion engine. Further, the starting clutch plays a role of preventing the engine from malfunctioning or stopping due to an overload with respect to the internal combustion engine, and allows the internal combustion engine to sufficiently exhibit its performance.

Examples of automatic starting clutches that automatically perform the function of the starting clutch include a fluid clutch, a plate clutch controlled by a control device, and an electromagnetic clutch.

For example, as disclosed in Japanese Patent Application Laid-Open No. 64-44338, the automatic starting clutch has an automatic starting clutch when the driver shifts the shift lever to the running range without depressing the accelerator pedal. There is a so-called creep function, that is, a function of moving or trying to move the vehicle by the torque transmitted.

By the way, in the conventional creep control with the automatic starting clutch, the clutch transmission torque is controlled so as to be the target clutch transmission torque corresponding to the engine speed. In this creep control, the higher the engine speed, the stronger the creep.

[0006]

In the conventional clutch control method as described above, there is a problem that the creep becomes too strong when the engine speed is high such as during the fast idle. If the creep is too strong, the brake pedal needs to be pressed hard, which imposes a heavy burden on the driver, and at this time, the vibration of the vehicle body increases. Further, there is a problem that the driver needs to pay attention to the sudden start when the brake pedal is released.

The present invention has been made in order to solve the above-mentioned problems, and provides a control method for a clutch in which the strength of the creep amount can be selected according to the operating condition and the range of use of the creep can be expanded. With the goal.

[0008]

A clutch control method according to the present invention includes the following steps. [1] A step of selecting a target clutch pressure corresponding to the creep amount based on the operation mode by the electronic control means. [2] A step of controlling the transmission torque of the clutch that disconnects the driving force between the internal combustion engine and the drive wheels based on the target clutch pressure by the transmission torque control means.

[0009]

In the present invention, in the first step, the electronic control means selects the target clutch pressure corresponding to the creep amount based on the operation mode. Then, in the next step, the transmission torque of the clutch that disconnects the driving force between the internal combustion engine and the drive wheels is controlled by the transmission torque control means based on the target clutch pressure.

[0010]

【Example】

Example 1. A configuration of a clutch control device used for implementing the first embodiment of the present invention will be described with reference to FIG. Figure 1
FIG. 1 is a diagram showing a configuration of a clutch control device used for implementing Embodiment 1 of the present invention. In the drawings, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, 2 is a belt drive type continuously variable transmission, 2A is a belt, 4 is a drive side pulley, 6 is a drive side fixed pulley part piece, 8 is a drive side movable part piece, and 10 is a driven side. A pulley, 12 is a driven-side fixed pulley section piece, and 14 is a driven-side movable pulley section piece.

The drive pulley 4 is a rotary shaft 1 which is an input shaft.
Drive side fixed pulley part 6 fixed to 6 and rotary shaft 16
The drive-side movable pulley portion 8 is mounted on the rotating shaft 16 so as to be movable in the axial direction and non-rotatable. The driven side pulley 10 is also fixed to the driven side fixed pulley portion piece 1 fixed to the rotary shaft 17 which is an output shaft, like the driving side pulley 4.
2 and a driven side movable pulley portion piece 14.

Housings 18 and 20 are mounted on the driving side movable pulley portion piece 8 and the driven side movable pulley portion piece 14, respectively, and hydraulic chambers 22 and 24 are formed respectively. The hydraulic pressure receiving area of the drive side movable pulley portion 8 of the hydraulic chamber 22 is
It is set larger than the hydraulic pressure receiving area of the driven side movable pulley portion 14. As a result, the belt ratio, which is a gear ratio, is changed by controlling the hydraulic pressure that acts on the hydraulic chamber 22.

In the hydraulic chamber 24, the driven side movable pulley section piece 14 is attached in a direction to reduce the groove width between the driven side fixed pulley section piece 12 and the driven side movable pulley section piece 14. A biasing means 26 including a biasing spring is provided. The biasing means 26 prevents slippage by maintaining a large gear ratio on the full low side and maintaining the holding force of the belt 2A when the hydraulic pressure is low such as at the time of starting.

Oil pump 28 provided on the rotary shaft 16
Pumps the hydraulic oil that has flowed back into the oil pan 100 through the strainer 102 and pressure-feeds it to the oil passage 32. The oil passage 32 communicates with the hydraulic chamber 24, and also communicates with the hydraulic chamber 22 via the primary pressure control valve 34, which is a shift control valve controlled by the three-way solenoid valve 42 through the oil passage 40, and the oil passage 30.

Further, the oil passage 32 communicates with the oil passage 64 via the clutch pressure control valve 52 controlled by the three-way solenoid valve 58 through the oil passage 56. The line pressure, which is the oil pressure in the oil passage 32, is regulated to, for example, 6 to 25 Kgf / cm ² by the line pressure control valve 44 controlled by the three-way solenoid valve 50 through the oil passage 48.

By means of the pressure regulating valve 38 for reducing the line pressure, the oil passage 60 is controlled at a constant pressure, for example, 4.2 Kgf /.
The pressure is adjusted to cm ^2, and the pressure is guided to each control valve 34, 44, 52 and each three-way solenoid valve 42, 50, 58.

The clutch pressure, which is the oil pressure of the oil passage 64, is detected by the oil pressure sensor 68 connected to the oil passage 64. Further, the oil passage 64 communicates with the clutch hydraulic chamber 72. The hydraulic clutch 62, which is a starting clutch, includes an input side casing 70 attached to the rotating shaft 17, a clutch hydraulic chamber 72 provided in the input side casing 70,
A piston 74 pushed by the hydraulic pressure of the hydraulic chamber 72, an annular spring 76 for urging the piston 74 in a direction to pull it back, a pushing force of the piston 74 and the annular spring 7
A pressure plate 78 that can be moved back and forth by the urging force of 6,
The friction plate 80 on the output side and the pressure plate 82 fixed to the casing 70 are included.

The hydraulic clutch 62 includes a clutch hydraulic chamber 72.
When the clutch pressure applied to is increased, the piston 74 pushes forward to press the pressure plate 78 and the pressure plate 82 against the friction plate 80, and a so-called coupled state is established. On the other hand, when the clutch pressure is lowered, the piston 74 is pulled back by the urging force of the annular spring 76 to separate the pressure plate 78 and the pressure plate 82 from the friction plate 80, and a so-called clutch disengaged state is established. By engaging and disengaging the hydraulic clutch 62, the continuously variable transmission 2
The driving force output by is interrupted.

An input shaft rotation detecting gear 84 and a rotation detector 86 are provided outside the housing 18. The output shaft rotation detection gear 88 and the rotation detector 9 are provided outside the housing 20.
0 is set. In this clutch control device, the rotation detector 8
The input shaft speed N1 detected in 6 is the engine speed Ne.
Therefore, the electronic control unit 98 calculates the gear ratio Rc = N1 / N2 from the input shaft rotational speed N1 and the output shaft rotational speed N2 detected by the rotation detector 90.

The hydraulic clutch 62 includes a forward gear 92F.
And an output transmission gear 92 including a reverse gear 92R
Is provided. A rotation detector 96 that detects the rotation speed of the final output shaft 94 is provided near the reverse gear 92R. The final output shaft 94 is connected to a final reduction gear, a differential mechanism, a drive shaft, and drive wheels (not shown). Therefore, the vehicle speed can be calculated from the rotation speed N3 detected by the rotation detector 96. Further, the input / output rotational speed difference of the hydraulic clutch 62 = | N1-N2 |, that is, the clutch slip amount can also be calculated.

Pressure sensor 68, rotation detectors 86, 9
0, 96 and various signals from the oil temperature sensor 66 for detecting the oil temperature of the oil pan 100, various signals such as throttle opening, accelerator switch signal, brake signal, power mode option signal and shift lever position signal. An electronic control unit 98 for inputting and controlling is provided. The electronic control unit 98 determines various control modes based on these input signals for operating state detection, and controls the line pressure, the gear ratio, and the clutch disengagement state so as to control the line pressure three-way solenoid valve 50. , A three-way solenoid valve 42 for shifting control,
The three-way solenoid valve 58 for controlling the clutch pressure is operated.

The function of the input signal input to the electronic control unit 98 will be described. (1) Shift lever position detection signal The range signals such as P, R, N, D, and L contribute to control of the line pressure, gear ratio, and clutch required for each range. (2) Throttle opening detection signal The engine torque is detected from the data input to the program in advance, which contributes to the determination of the target gear ratio or the target engine speed. (3) Accelerator switch signal The driver's will is detected by the depression state of the accelerator pedal, which contributes to the determination of the control method during running or starting.

(4) Brake signal The presence or absence of the brake pedal depressing operation is detected to contribute to the determination of a control method such as clutch disengagement. (5) Power mode option signal Used as an option to make the vehicle performance sporty or economical. (6) Snow mode signal In the case of a snowy road or a slippery road surface, the driver selects a control mode suitable for the road surface condition.

The primary pressure control valve 34 for gear shift control controlled by the three-way solenoid valve 42 is connected to the hydraulic chamber 2 through the oil passage 30.
By connecting the hydraulic pressure 2 to the line pressure side or the atmosphere side, the gear ratio is shifted to the overdrive side or the full low side.

The clutch pressure control valve 52 for controlling the clutch, which is controlled by the three-way solenoid valve 58, conducts the oil pressure of the clutch oil pressure chamber 72 to the line pressure side or the atmosphere side through the oil passage 64 to change the line pressure to the atmospheric pressure ( Oil pressure up to 0) is realized.

This clutch control has four basic modes. The basic mode will be described below. (1) Neutral mode When the shift lever position is N or P, the clutch is completely disengaged, and the clutch pressure is the minimum value (= 0). (2) Hold mode When the shift lever position is D, L, or R and there is no depression of the accelerator pedal, the clutch pressure is such that the clutch plate comes into contact with the engine when it is desired to decelerate engine torque by decelerating while starting or holding the vehicle. Is low. Creep control belongs to this mode. (3) Start mode In the case of starting from a nearly stopped state (normal start) or re-engagement of the clutch while driving (special start), the clutch pressure prevents the engine from rising and allows the vehicle to operate smoothly. It is an appropriate value according to the transmission torque. (4) Drive mode The clutch pressure is a value at which the engine torque can be sufficiently transmitted while the clutch is completely engaged in the running state.

By the way, the electronic control means of the present invention is the clutch pressure control valve 52 and the three-way solenoid valve 5 in the above-mentioned device.
8, a pressure sensor 68 and an electronic control unit 98,
The transmission torque control means of the present invention comprises the hydraulic clutch 62 and the oil passage 64 in the above-mentioned device.

Next, the operation of the above-described first embodiment will be described with reference to FIG.
Description will be made with reference to FIGS. 3, 4 and 5. 2 is a block diagram showing the creep control of the first embodiment of the present invention, FIG. 3 is a characteristic diagram showing the relationship between the control duty and the clutch pressure of the first embodiment of the present invention, and FIG. 4 is the clutch of the first embodiment of the present invention. FIG. 5 is a characteristic diagram showing the relationship between pressure and clutch transmission torque.
Is a flow chart showing the operation of the first embodiment of the present invention.

In FIG. 2, the flow of driving force is as follows: engine 1 → transmission (CVT) 2 → hydraulic clutch 62 → forward / reverse switching device 92 → speed reducer / differential device 93 → driving wheel 91.

FIG. 4 shows an example of clutch transmission torque characteristics with respect to the clutch pressure of the hydraulic clutch 62. In FIG. 4, the force at which the annular spring 76 tries to pull back the piston 74 and the clutch pressure when the clutch pressure becomes substantially equal to the force pushing the piston 74 are called the touch-off pressure,
It is the starting point of the clutch transmission torque.

In FIG. 2, the clutch pressure, which is the oil pressure in the oil passage 64, is produced by adjusting the line pressure by the clutch pressure control valve 52 controlled by the output pressure of the three-way solenoid valve 58, and electronically controlled by the oil pressure sensor 68. It is fed back as the clutch pressure 202 in the portion 98. A deviation 204 is output from the target clutch pressure 201 and the clutch pressure 202. This deviation 204
Is input to the clutch pressure control law 205 and is calculated to a command duty 206 which is an operation amount. The clutch pressure control law 205 is, for example, PID control. The duty driving means 207 uses the command duty 206
The three-way solenoid valve 58 is driven with a duty based on.

This drive duty and clutch pressure control valve 5
An example of the relationship of the clutch pressure which is the output of 2 is shown in FIG. The vertical axis of FIG. 3 is normalized by the line pressure which is the input of the clutch pressure control valve 52.

FIG. 5 is a flow chart showing the operation of determining the target clutch pressure by the electronic control unit 98. When the determination process starts (step 300), the control mode is determined, that is, it is determined whether or not the hold mode is set. If the hold mode is not set, another target clutch pressure is calculated (step 310), and the target clutch pressure is set. Then (step 312), the process ends (step 31).
4).

If the hold mode is set in the determination process (step 302), it is determined whether the engine is in the fast idle (step 304). If the engine speed is the same during the fast idle, the value is low. The low creep map is selected and the target clutch pressure corresponding to the current engine speed is determined (step 306),
The process proceeds to step 312 and subsequent steps. If it is determined that the first idle is not in the determination process (step 304), the normal creep map is selected (step 30).
8) The target clutch pressure is determined as in the case of the first idle.

In the first embodiment, the engine, the transmission (C
Although VT) and the starting clutch are controlled in this order, it goes without saying that the same applies to the engine, the starting clutch, and the transmission. Although the starting clutch has been described as a wet hydraulic clutch, any clutch that can electronically control the clutch transmission torque may be used, and a dry clutch, an electromagnetic clutch, or the like may be used. Furthermore, the clutch that performs creep control is
Although the starting clutch is used in the first embodiment, the clutch capacity may be relatively small during creep control, so other clutches interposed between the engine and the drive wheels, for example, a shift clutch for shifting or forward / reverse switching. The same creep control is included in the clutch.
Further, in the first embodiment, a map having a lower value than usual is selected during the fast idle, but a method of subtracting a predetermined amount from the normal map value is also included.

The first embodiment of the present invention, as described above,
Even during fast idle when the engine speed is high, the control is automatically performed so that the creep amount is almost normal, so vibration of the vehicle body during braking can be reduced, and the same driving operation as normal can be performed during fast idle. As a result, it is possible to reduce the burden on the driver and to improve safety, because it is not necessary to pay attention to the brake operation and sudden jumping out.

Also, if the creep strength can be selected to be high, the normal creep can be selected to allow normal slow speed movement on almost level ground, and the strong creep can be selected to cause slipperiness. It is possible to smoothly start on a road surface or a snowy road, prevent backward slippage when starting on an uphill road, and increase the range of use of creep.

[0039]

As described above, according to the present invention, the step of selecting the target clutch pressure corresponding to the creep amount based on the operation mode by the electronic control means, and the internal combustion engine based on the target clutch pressure by the transmission torque control means. Since it includes the step of controlling the transmission torque of the clutch that disconnects the driving force between the engine and the drive wheel, the strength of the creep amount can be selected according to the operating condition, and the range of use of creep can be expanded. Play.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a clutch control device used to implement a first embodiment of the present invention.

FIG. 2 is a block diagram showing creep control according to the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between duty and clutch pressure according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between clutch pressure and clutch transmission torque according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the first embodiment of the present invention.

[Explanation of symbols]

 2 Transmission (CVT) 62 Hydraulic clutch 52 Clutch pressure control valve 58 Three-way solenoid valve 64 Oil passage 68 Pressure sensor 98 Electronic control unit

Claims (1)

[Claims] 1. A step of selecting a target clutch pressure corresponding to a creep amount based on an operation mode by an electronic control means, and a driving force between an internal combustion engine and driving wheels based on the target clutch pressure by a transmission torque control means. A method of controlling a clutch, comprising the step of controlling a transmission torque of a clutch for connecting and disconnecting the clutch.