JPH01288662A - Device for controlling lock-up clutch - Google Patents

Abstract

PURPOSE:To accurately prevent a shock in the torque converter of the automatic transmission of a vehicle by reengaging to be a slipping condition when the difference between engine speed and turbine rotating speed reaches a target rotating speed after releasing slip lock-up. CONSTITUTION:As vehicle speed and throttle opening enter a set slip lock-up zone, a slip lock-up control means is operated. Thereby, the engaging force of a lock-up clutch is adjusted in accordance with the difference between engine speed and turbine rotating speed. When the engine speed is reduced to below a set value with throttle being totally closed, the slip lock-up is released, shifting to converter driving. At the time of reaccelerating, the slip lock-up control is resumed by a reengaging timing setting means when the difference between the engine speed and turbine rotating speed becomes a target rotating speed difference.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a lock-up clutch in a torque converter that puts the lock-up clutch in a slip state in a predetermined region.

(Prior art) In the torque converter of an automatic transmission for a vehicle, a so-called lock amplifier clutch has been installed (:11) in order to improve power transmission efficiency by switching the converter drive to a direct drive in a predetermined operating range. However, if complete direct drive is performed using a lock-up clutch, vibrations and torque fluctuations on the engine side will be transmitted directly to the transmission side, resulting in a worsening of the drive feel. As described in Japanese Unexamined Patent Application Publication No. 57-33253, control is performed to bring the lock-up clutch into a semi-engaged, so-called slip state, and to converge the amount of slip, that is, the rotational speed difference between the input and output shafts, to a target value. By performing such a slip lockup, it is possible to reduce the deterioration in fuel efficiency caused by convergence drive, and also to avoid the deterioration in drive feeling caused by direct drive.

This is the area where you perform a slip lockup.

The range in which complete lockup is performed and the range in which converter drive is performed after lockup is released are usually set by the vehicle speed and throttle opening at each gear stage. Furthermore, these areas are set for acceleration and deceleration, respectively.

By the way, in a torque converter that performs such a slip lockup, if a sudden deceleration is performed with the throttle fully closed within the slip lockup region, there is a risk that the engine speed or turbine speed will suddenly drop and cause an engine stall. .

Therefore, in order to prevent engine I-le from occurring during fully closed deceleration, the slip lock-up is released when the engine speed drops below a set value. When the lock-up clutch is released and the accelerator is pressed to accelerate again from the released state, the lock-up clutch must be re-engaged to the slip state, but a shock often occurs when the lock-up clutch is re-engaged. This causes the problem of deterioration of the feeling. Conventionally, regarding the shock of the lock-up clutch, for example,
Publication No. 03956 discloses an automatic transmission in which a lock-up clutch is engaged during driving to perform direct drive, and a lock-up clutch is disengaged during gear shifting to perform converter drive. A system is described in which the shift timing is set so that the lock-up clutch is engaged when the rotational speed difference on the output shaft side becomes less than a predetermined value to reduce shift shock. However, in the prior art including the one in the same publication, in a torque converter that performs slip lockup in a predetermined area as described in -, there is a method to release the slip lockup during deceleration to prevent engine stalling. Based on this assumption, there is no disclosure of a means for accurately preventing shock when re-entering the slip lock-up state during re-acceleration after release of lock-up during deceleration.

(Object of the invention) The present invention has been made in view of the problems mentioned in 1.
The purpose is to prevent shock when the lock-up clutch is shifted to the slip state again after fully closed deceleration.

(Structure of the Invention) The present invention is based on the shock that occurs when reaccelerating after fully closed deceleration in a torque converter that performs slip lockup, or when the transition to a slip state occurs due to the difference between the engine rotational speed and the turbine rotational speed at =4-. By discovering that this was caused by the difference in rotational speed, we were able to find an accurate means of setting the timing for reconnecting the lock-up clutch and shifting to the slip state.
Its configuration is as shown in FIG. That is, the lock-up clutch control device according to the present invention includes a lock-up clutch that is installed between the input and output shafts of a torque converter and directly connects the input and output shafts in a predetermined operating range, and Engine rotation speed detection means detects the engine rotation speed, turbine rotation speed detection means detects the turbine rotation speed on the output shaft side, and adjusts the coupling force of the lock-up clutch according to the difference between the engine rotation speed and the turbine rotation speed. slip lockup control means for controlling the rotational speed difference between the input and output shafts to a target rotational speed difference; vehicle speed detection means for detecting vehicle speed; throttle opening detection means for detecting the throttle opening of the engine; slip area setting means for setting an operating range of the slip lockup control means based on the throttle opening and the throttle opening; and the slip lockup control when it is detected that the engine speed reaches a set value with the throttle closed. a slip lockup release means for stopping the operation of the means to release the slip lockup; and the slip lockup control means when the difference between the engine rotation speed and the turbine rotation speed reaches the target rotation speed difference after the slip lockup is released. An additional feature is that the lock-up clutch is provided with ``11 connection timing setting means'' for restarting the operation of the lock-up clutch and reconnecting the lock-up clutch to the slip state.

(Function) When the vehicle speed and throttle opening enter the set slip lock-up region, the slip lock-up control means is activated, and thereby the lock-up clutch coupling force is adjusted according to the difference between the engine speed and the turbine speed. or A1. !
], and the slip lockup state is controlled so that the rotational speed difference between the driver and the output shaft becomes the target rotational speed difference. In the slip lockup state, when the engine speed is reduced to below the set value by the throttle opening,
The slip lockup release means is activated to release the slip lockup and shift to converter drive.

This prevents the engine from stalling during sudden deceleration. In addition, when decelerating and re-accelerating by depressing the accelerator after the slip lockup has been released in this way, the reconnection timing setting means As a result, the slip lockup control is restarted, and the lockup drive in the slip state is again performed. By suppressing the difference between the engine rotational speed and the turbine rotational speed within a predetermined value at the time of transition to slip lockup, the difficulty when entering the sliplockup state again is reduced. 2 (Example) Hereinafter, an example will be described based on the drawings.

FIG. 2 shows a torque converter according to an embodiment of the present invention (J
This diagram schematically shows the rough slip control.

As shown in the figure, a torque converter 2 that transmits the power of an engine 1 to an output shaft includes a lock-up clutch 3 that directly connects the driver and the output shaft. Rotation sensors 6 are provided on the human power shaft 4 and the output shaft 5 of the torque converter 2, respectively.
, 7 are arranged, and a slip amount detection means 8 detects the amount of slip from the detected values of both rotation sensors 6 and 7, and a deviation calculation for calculating the deviation of the actual slip amount detected by the detection means 8 from the target slip amount. means 9, a feedback amount calculation means 10 for calculating a feedback amount using the deviation determined by the calculation means 9, and a slip amount control means 11 according to the foot high tooth calculated by the calculation means 10. Feedback control means 12 are provided for driving. In such a configuration, the feedback amount calculation means 10 calculates the feedback amount from the deviation of the actual slip amount from the target slip amount, and the slip amount control means 11 operates based on the calculated value. As a result, when the actual slip amount exceeds the target slip amount, the lock-up clutch 3 is controlled in the engaging direction, and when the actual slip amount is less than the target slip amount, the lock-up clutch 3 is controlled in the releasing direction. In this way, the slip amount is controlled to converge to the target value.

Next, the structure of the torque converter of this embodiment and its control bending pressure circuit will be explained with reference to FIG.

The converter 2 includes a pump 14 that is fixed to one side of a case 13 connected to the input shaft 4 and rotates integrally with the input shaft 4.
and a turbine 15 that is rotatably disposed on the other side of the case 13 to face the pump I4 and is rotationally driven via hydraulic oil by the rotation of the pump 14, and between the pump 14 and the turbine 15. A starter 16 is provided between the turbine 15 and the case 13, and a lock-up clutch 3 is provided between the turbine 15 and the case 13. The rotation of the turbine 15 is caused by the output shaft 5
The signal is output to a speed change gear mechanism (not shown). The lock-up clutch 3 is connected to the output shaft 5, and when coupled to the case 13, the input shaft 4 and the output shaft 5 are directly connected through the case 13.

An operating surface is introduced into this torque converter 2 via a lock-up valve 18 and a converter in-line 19 by a main line I7 connected to an oil pump (not shown), and the pressure of this operating surface causes the lock-up clutch to be divided into three parts. There is now one force in the time bond direction. Further, a lock-up release line 2I extending from the lock-up valve 18 marked with ('', -]- is connected to the space 20 between the lock-up clutch 3 and the case I3. When a bending force (release pressure) is introduced into the lock-up clutch 3 (
To be released. Further, a converter outer line 24 is connected to the torque converter 2 via a check valve 22 to an oil cooler 23 without sending out its operating surface.

On the other hand, the ``-8'' candlestick release line 21 has a spool 18a and a spring +8b that biases it to the right side, and the boat 18c to which the ``-8'' candle up release line 21 is connected. A pressure regulating boat 1-18d and a train boat 18e to which the main line 17 is connected are provided on both sides.

Also, at the right end of the valve 18 in the drawing, there is a control line 25 for applying pilot pressure to the spool 18a.
is connected to the control line 25, and a decoty solenoid valve 27 is installed on a train line 26 branched from this control line 25. This duty solenoid valve 27 repeatedly turns on and off at a duty ratio according to an input signal to open and close the train line 26 in extremely short cycles, thereby adjusting the pilot pressure in the control line 25 to correspond to the duty ratio. Adjust to value. This pilot pressure is the spool 18 of the lock-up valve 18
A is applied in a direction opposite to the force of the spring 18b. Further, the spool 18a has a spring l8b.
Release pressure within the lockup release line 2I acts in the same direction as the force.

When the spool 18a moves due to the power relationship between these forces, the main line 17 is moved via the lockup release line 21 or the pressure regulating boat +8d.
or communicates with the train boat 18e. As a result, the lock-up release pressure (pilot pressure) is controlled to a value corresponding to the duty ratio of the duty solenoid valve 27. When the duty ratio is the maximum value 100, the flow rate from the control line 25 is the maximum. The pilot pressure is at its minimum, and therefore the release pressure is at its minimum.
and lock-up clutch 3 is fully engaged.

Further, when the duty ratio is the minimum value O, the flow rate becomes the minimum, the pilot pressure or the release pressure becomes the maximum, and the lock-up clutch 3 is completely released. At a duty ratio between the maximum value and the minimum value, the lock-up clutch 3 is in a slip state. In this state, the release pressure is adjusted according to the duty ratio, thereby controlling the slip amount of the lock-up clutch 3.

Next, check the duty solenoid valve 27.

Explain the control of the party ratio.

As shown in FIG. 4, this control system includes a control unit 28, and the control unit 28 includes a vehicle speed sensor 29 for detecting vehicle speed, and a slot.

A throttle sensor 30 that detects the torque opening, a gear position sensor 31 that detects the gear position of the automatic transmission, an engine rotation sensor 32 that detects the engine rotation speed, and a rotation speed of the output shaft (turbine shaft) 5. Each detection signal from the turbine rotation sensor 33 is manually input. The control unit 28 first determines whether the current driving range is in the slip lockup range from the vehicle speed and throttle opening, and if it is in the slip lockup range, the engine speed is The duty ratio is adjusted so that the difference between the turbine speed and the turbine rotation speed becomes a predetermined value. This type of slip control is performed in the area marked ■ in FIG. 5.

In addition, in Fig. 5, the solid line indicates the turbine rotation speed, and
The broken line indicates the engine speed. Then, from this state, when the throttle is fully closed and suddenly decelerates (area ■)
When the engine speed falls below the set value, the slip lockup is released and the converter is driven.

Therefore, the engine speed drops to the idle speed, while the turbine speed continues to drop as the vehicle speed increases (region ■).

This region of slip lockup release during deceleration corresponds to the region indicated by A in the shift diagram of FIG. 6. Also,
The areas in which slip control is performed are set to areas 13 (3rd speed) and C (4th speed) in FIG. In FIG. 6, the solid line indicates the shift line of the soft amplifier, and the broken line (the shift line of JFT Town) indicates the complete lock-up area.

Next, after the slip lockup is released in the fully closed deceleration state, when the accelerator is depressed (region ■ in Figure 5)
, the engine speed rises and falls rapidly, while the turbine speed gradually rises and falls due to converter drive. Then, the engine speed becomes higher than the turbine speed, and the difference becomes the set value (■ in Figure 5)
Slip control is restarted at , and thereafter control is performed so that the difference between the engine rotation speed and the turbine rotation speed becomes a predetermined value.

FIGS. 7 and 8 are flowcharts for executing the above control in this embodiment.

In the flag setting routine shown in Fig. 7, the engine speed and TVO (throttle opening) are read, and the TV
Check whether O is less than TVOO, that is, the fully closed value.

If TVO≦TVOO, that is, the throttle is fully closed, then check whether the engine speed R is less than the set rotation speed RO for lock-up release, and if R is less than RO, the lock-up is released. flag.

Furthermore, if TVO≦TVOO does not hold, that is, the throttle is not fully opened, the flag is reset.

Next, the main routine shown in FIG. 8 will be explained.

When started, first, the vehicle speed, TVO (throttle opening), engine speed, turbine speed, and lock-up flux are read.

Next, it is determined whether the vehicle is in a slip zone based on the vehicle speed and throttle opening. Then, if it is not in the pickpocket/nobu zone, the duty ratio is set to zero.

If it is in the slip zone, then it is determined whether or not the previous time was in the slip lockup release zone.

If it was in the release zone last time, that is, if it is now in the slip zone, the duty ratio is set to an initial value of 30.

Also, if the current slip zone is the previous slip zone and the previous slip zone was not the release zone, that is, the slip zone continues from the previous time, it is next checked to see if the lockup release flag is set.

If it is not, then check whether the previous duty ratio is not zero, and if it is not zero, perform normal slip lockup control (■, ■, ■ in Figure 5).
area). In other words, check whether the difference between the engine speed N and the turbine speed N7 is larger than the set value α, and if the dial is in bold, increase the duty ratio by △d, and if the difference between the engine speeds is larger than α, increase the duty ratio. The ratio is conversely reduced by △d and a decoty signal is output.

Even if the slip zone continues from the previous time, if the release flag is set, the slip lockup is released = 16- and the duty ratio is set to zero (■ in Fig. 5).

Also, if the previous leverage ratio is zero, that is, the slip lockup is released, then the engine rotation speed N8 and the turbine rotation speed N. Check whether the difference between the two values has reached the set value α, and if the difference has reached the set value α, slip control is resumed, and the duty ratio is set to the initial value of 3.
Set to 0. Also, if the set value α is not reached (J), the leverage ratio is set to zero.

(Effects of the Invention) Since the present invention is configured as shown in (I) to (II), it is possible to smoothly return to the slip state after the slip lockup is released by fully closed deceleration without any slippage. It can be carried out.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of the present invention, Fig. 2 is a basic configuration diagram of torque converter control according to an embodiment of the invention, Fig. 3 is an overall diagram of the embodiment, and Fig. 4 is a control diagram of the embodiment. A schematic diagram of the system, FIGS. 5 and 6 are control characteristic diagrams of the same embodiment, and FIGS. 7 and 8 are flowcharts for executing control of the same embodiment. 2 Torque converter, 3 Lock-up clasp, 4
Human power shaft, 5 Output shaft, 6.7 Rotation sensor, 18. Lock-up valve, 27. Decoty solenoid valve, 28 control unit. Agent Patent Attorney Jun Shinfuji - Figure 1, Figure 3

Claims (1)

[Claims] (1) A lock-up clutch that is provided between the input and output shafts of the torque converter and directly connects the input and output shafts in a predetermined operating range, and an engine rotation speed detection means that detects the engine rotation speed on the input shaft side. , a turbine rotation speed detection means that detects the turbine rotation speed on the output shaft side, and a lock-up clutch coupling force that adjusts according to the difference between the engine rotation speed and the turbine rotation speed to target the rotation speed difference between the input and output shafts. A slip lockup control means for controlling the difference in rotational speed, a vehicle speed detection means for detecting the vehicle speed, a throttle opening detection means for detecting the throttle opening of the engine, and the slip lockup based on the vehicle speed and the throttle opening. A slip area setting means for setting an operating area of the control means, and when it is detected that the engine speed reaches a set value with the throttle fully closed, the operation of the slip lockup control means is stopped to release the slip lockup. and a slip lockup release means for resuming operation of the slip lockup control means to place the lockup clutch in a slip state when the difference between the engine rotational speed and the turbine rotational speed reaches the target rotational speed difference after the sliplockup is released. A control means for a lock-up clutch, comprising: a reconnection timing setting means for reconnecting the lockup clutch.