JPH04175571A - Engaging force control device for fluid joint - Google Patents

Abstract

PURPOSE:To engage a lockup clutch smoothly by increasing the engaging force gradually with feed-forward control so that the lockup clutch will be in perfect engaged state at the predicted engagement timing when the engine operating condition lies within the slip region. CONSTITUTION:A controller 20 reads signals from various sensors 21-25 and judges whether the engine operating condition lies within the lockup region of a torque converter 10 preset for each shift position, and if no, another judgement is made to know whether it lies within the slip region. If judgement is such that the current condition lies within the slip region and the acceleration is greater than the reference acceleration value, the feed-forward control on the basis of No.1 function calculated is executed, and the duty initial value is read from the No.1 function, and a control signal is given to a duty solenoid valve 19. Thus the pilot pressure impressed to a spool of the lockup valve 10 or the lockup disengaging pressure adjusted by this valve 10 is decreased gradually, and perfect engaged state is obtained when the lockup attainment time has elapsed since the control was started.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fluid coupling used in an automatic transmission or the like, and particularly to a fastening force control device for a fluid coupling equipped with a lock-up clutch.

(Prior Art) Generally, automatic transmissions installed in vehicles are equipped with fluid couplings, and typically a torque converter with a torque conversion function is used as this type of fluid coupling. It is. In this torque converter,
In order to reduce the deterioration of engine fuel efficiency caused by so-called slippage of the converter, a lock-up clutch is provided that directly connects the converter and the output member in a predetermined operating range that does not require torque increase action or shift shock absorption action. may be provided.

By the way, in a torque converter (hydraulic coupling) equipped with this type of lock-up clutch, attempts have been made to adopt control that causes the converter state to transition from a so-called converter state in which torque is transmitted via fluid to a lock-up state via a slip state. There is. For example, according to Japanese Patent Publication No. 63-13060, a plurality of slip regions are set between a converter region and a lock-up region, and the slip amount (rotational speed difference between input and output members) decreases as the distance approaches the lock-up region. When the engine operating condition falls within each of the above slip ranges, the actual slip amount is fed back so that the target slip amount can be obtained.The 4-up clutch is engaged while slipping, which suppresses torque converter slippage and improves fuel efficiency. At the same time, transmission of vibration can be suppressed.

(The invention or the problem to be solved) However, when controlling the fastening force by feedback control as described in the above publication, there is a problem that the stability of the control is impaired due to response delay. When variable control is performed, the effect of response delay becomes noticeable.

The present invention addresses the above-mentioned problems when engaging the mouth/pull-up clutch through a slip/butt state, and makes it possible to smoothly engage the mouth/pull-up clutch without impairing control stability. The purpose is to

(Problems to be Solved by the Invention) In other words, the fastening force control device for a fluid coupling according to the present invention has the following problems:
A lock-up clutch is provided on a fluid coupling installed in a power transmission path from an engine to directly connect input and output members of the coupling, and a fastening force variable means for changing the fastening force of the lock-up clutch is provided. and in which the lock-up clutch is engaged from a non-engaged state to a slip state, an engagement timing that predicts when the operating state of the engine will shift to the engagement region when it is in the slip region. A prediction means and a feedforward control means for operating the engagement force variable means to gradually increase the engagement force so that the lock-up clutch is fully engaged at the engagement timing predicted by the means. It is characterized by

(Function) According to the above configuration, when the operating state of the engine is in the slip region, the feedforward control is performed so that the lock-up clutch is fully engaged at the engagement timing predicted by the engagement timing predicting means. Since the engagement force is gradually increased, the lock-up clutch is engaged smoothly without compromising control stability, and as the engagement force increases, the amount of slip decreases, improving fuel efficiency. will also improve.

(Example) Examples of the present invention will be described below.

First, the structure of the torque converter and its control hydraulic circuit will be explained with reference to FIG. Pump 4 that rotates integrally with
A turbine 5 is rotatably provided on the other side of the case 3 so as to face the pump 4, and is rotationally driven via hydraulic oil by the rotation of the pump 4. A starter 6 is interposed between the turbine 5 and the case 3 to increase torque when the speed ratio of the turbine rotation speed to the pump rotation speed is below a predetermined value; and a lock-up clutch 7 is interposed between the turbine 5 and the case 3. and has. and,
The rotation of the turbine 5 is outputted by a turbine shaft 8 and inputted to a speed change gear mechanism (not shown), and the lock-up clutch 7 is connected to the turbine shaft 8 and fastened to the case 3. At this time, the engine output shaft 2 and the turbine shaft 8 are directly connected through the case 3.

Further, hydraulic oil is introduced into the torque converter 1 through a main line 9 led from an oil pump (not shown) through a lock-up valve 10 and a converter inline 11. The lock-up clutch 7 is always urged in the engagement direction by pressure, and the space 12 between the clutch 7 and the case 3 has a port/tuck-up release line led from the port/tuck-up valve 10. 13 is connected, and when hydraulic pressure (release pressure) is introduced into the space 12 from the line 13, the lock-up clutch 7 is released. Further, a converter outline 16 is connected to the torque converter 1 to send hydraulic oil to an oil cooler 15 via a pressure holding valve 14.

On the other hand, the lock-up valve 10 has a spool 10a.
A pressure regulating boat 10d and a drain boat 10e are provided with a main line 9 connected to both sides of the boat 10c to which the lockup release line 13 is connected. is provided. Further, a control line 17 for applying pilot pressure to the spool 10a is connected to the right end of the valve 10 in the drawing, and this control line 1
A duty solenoid valve 19 is installed in the drain line 18 that is connected to the drain line 7. This duty solenoid valve 19 is repeatedly turned ON and OFF at a duty rate according to an input signal to open and close the drain line 18 in extremely short cycles, thereby adjusting the pilot pressure in the control line 17 to correspond to the duty rate. Adjust to the desired value.

Then, this pilot pressure is applied to the lock-up valve 1.
The release pressure in the lock-up release line 13 is applied to the spool 10a of 0 in the direction opposite to the urging force of the spring 10b, and the release pressure in the lock-up release line 13 is applied to the spool 10a in the same direction as the urging force of the spring 10b. , the spool 10a is
moves, and the lock-up release line 13 is connected to the main line 9 (pressure regulation port 10d) or the drain port 10.
e, the lock-up release pressure is equal to the pilot pressure, that is, the dual inlenoid valve 1.
It is controlled to a value corresponding to a duty rate of 9. Here, when the duty rate is at its maximum value, the amount of drain from the control line 17 is at its maximum, and the pilot pressure or release pressure is at its minimum, so that the lock-up clutch 7 is completely engaged, and the duty rate is at its minimum value. When the value is 7, the drain amount becomes the minimum 7, and the pilot pressure or release pressure becomes the maximum, so that the lock-up clutch 7. At a duty rate between the maximum value and the minimum value, the lock-up clutch 7 is in a slip state, and in this state, the release pressure is adjusted according to the duty rate. As a result, the sleeve amount of the lock-up clutch 7 is controlled.

Next, a control system for controlling the engagement force of the lock-up clutch 7 will be explained. As shown in FIG. 2, this control system has a controller 20, which detects the vehicle speed of the vehicle. a throttle sensor 22 that detects the throttle opening of the engine, a gear position sensor 23 that detects the gear position of the automatic transmission, an engine rotation sensor 24 that detects the engine rotation speed, and the turbine shaft. A signal from a turbine rotation sensor 25 that detects the rotation speed of 8 is input.

Then, the controller 20 controls each of the above-mentioned sensors 21 to 2.
5, the duty rate of the duty solenoid valve 19 is calculated, and the torque converter 1 (lock up gear) is controlled according to the flowchart shown in FIG.

That is, the controller 20 first reads various signals from the sensors 21 to 25 in step S1, and then in step S2, determines the operating state indicated by the vehicle speed V and the throttle opening θ in advance for each gear. It is determined whether or not the torque converter 10 belongs to the set lock-up region (2). If it is determined that the torque converter 10 does not belong to the lock-up region (2), the process proceeds to step S3 and it is determined whether or not it belongs to the slip region (2). This slip area I is set on the low vehicle speed side (low engine rotation side) of the lock-up area (solid shaded area) of each gear stage, as shown by the dotted hatched area in FIG. Note that the remaining area (2) excluding the slip area I and the lock-up area (2) is the converter area where the lock-up clutch 7 is released, and FIG. 4 shows each area during acceleration, and each area during deceleration. The area is set separately.

When the controller 20 determines in step S3 that the operating state belongs to the slip region (2), the controller 20 proceeds to step S4 and performs an acceleration determination. That is, the acceleration α calculated from the vehicle speed V is compared with a predetermined reference acceleration α1 set in advance.

When the controller 20 determines that the acceleration α is in a large acceleration state where it is larger than the reference acceleration α, the controller 20 proceeds to step S5 and a 17th lag F1 indicating whether or not the first function f1 (t) for large acceleration is set. It is determined whether or not the value of t
) is calculated.

Here, to explain how to calculate the first function f+ (t), the memory of the controller 20 has a large acceleration function set with vehicle speed V and throttle opening θ as parameters, as shown in FIG. The map of the initial duty value DI and the lockup arrival time t1 for large acceleration set using the vehicle speed V and acceleration α as parameters as shown in FIG.
The map is memorized. And controller 2
0 reads out the large acceleration duty initial value DI and large acceleration lockup arrival time t1 from the above maps based on the current throttle opening θ, vehicle speed V, and acceleration α, and uses these values to: As shown in FIG. 7, the first function fx (tl is calculated and stored) such that the duty rate increases linearly from the initial duty value to 100% at the lock-up arrival time t1. become.

When the calculation process of the first function 11 (1) is completed, the controller 20 executes step Sf in the flowchart of FIG. 3, sets the value of the 17th lag Fl to 1, and The second function f2 (t)(
(details will be described later) is set to O.

Further, the controller 20 performs step S above.

If it is determined that the value of the first flag F1 is not set to 0, feedforward control based on 1(t) is executed using the first function calculated in step S6 according to a predetermined subroutine. In other words, when the controller 20 shifts to the control, the first function ft
The initial duty value D is read from (t), and a control signal is output to the duty solenoid valve 19 so that the initial duty value D1 is obtained. and,
The duty rate is changed according to the first leap number f1 (t) as time passes. Therefore, the pilot pressure applied to the spool 10a of the lock-up valve 10 shown in FIG. 1 or the lock-up release pressure by which the oil pressure is adjusted by the valve 10 is gradually reduced. As a result, as shown in FIG. 8, the lock-up clutch becomes a half-clutch state with a predetermined slip amount corresponding to the duty initial value D1, and the slip amount corresponds to the first rIR number ft (t). It gradually decreases at a predetermined slope and reaches a fully engaged state when the lock-up arrival time t1 has elapsed from the start of the control. In this case, since the slip amount of the lock-up clutch 7 is controlled according to the above-mentioned first interval fl (t) calculated in advance, occurrence of hunting due to response delay as in the case of feedback control is avoided. This means that the amount of slip changes smoothly.

On the other hand, when the controller 20 determines in step S4 in the flowchart of FIG. 3 that the acceleration α is in a small acceleration state smaller than the reference acceleration αl,
9, it is determined whether the value of the 27th lag F2 indicating the setting state of the second function f2 (t) for small acceleration is set to O, and if it is set to 0, the process proceeds to step SIO. The second function fz (t) is calculated according to the operating state.

In this case as well, the memory of the controller 20 5 contains the ma-tub of the initial duty value D2 for small acceleration, which is set using the vehicle speed V and the throttle opening θ as parameters, as shown in FIG. Similarly, the vehicle speed V
A map of the lockup arrival time t2 for small acceleration, which is set using the acceleration α and the acceleration α as parameters, is stored.

Here, to show the setting tendency of the map of the duty initial value D2 for small acceleration, the above duty initial value D1 for large acceleration is shown.
Compared to this, the initial duty value D2 at the same throttle opening is set smaller overall. Furthermore, the map of the lockup arrival time t2 for small acceleration is also set to be longer than the lockup arrival time t□ for large acceleration by the amount of smaller acceleration.

Then, the controller 20 reads out the initial duty value D2 for small acceleration and the lockup arrival time t2 for small acceleration from each of the above maps based on the current values of throttle opening θ, vehicle speed V, and acceleration α, and also reads these values. As shown in FIG.
The second function f2 increases linearly so that it becomes 100% at
(1) is calculated and stored. In this case, assuming that the throttle opening θ and the vehicle speed V are the same, the initial duty value D2 is relatively small compared to the first function fl (t) shown by the chain line, and the opening/tuck-up arrival time t2 is relatively small. This results in a second leap number f2 (t) that is relatively long.

When the calculation process of the second function f2 (t) is completed, the controller 20 executes step Stt in the flowchart of FIG. 3, sets the value of the first flag F1 to 0, and sets the value of the second flag F2. Set the value to 1.

Further, when the controller 20 determines that the value of the 27th lag F2 is not set to 0 in the step S5, the controller 20 performs the step S in accordance with a predetermined subroutine.
Feedforward control is executed based on the second function f2(1) calculated by IO.

Therefore, as shown in FIG. 12, the amount of slip and soar of the lock-up clutch decreases smoothly as in the case of large acceleration. In this case, the time it takes to reach the lock-up state becomes relatively longer due to the smaller acceleration α compared to the case of large acceleration.

Note that, for example, when performing feedforward control based on the first function f+ (t), the acceleration α becomes the reference acceleration α! When it becomes smaller than , the second leap number f2° (1)
This will lead to a transition to feedforward control.

Then, the controller 20 performs step S4 in FIG.
When it is determined that the acceleration α becomes zero or a negative value, that is, when it is determined that the vehicle is in a low-speed running state or a deceleration state, the process moves to step Sts, and feedback control is executed to maintain a constant slip amount (for example, 80 rpm). , in step S, the first and 27th lags F1 and F2 are each set to 0. In this feedback control, the deviation between the engine rotational speed and the turbine rotational speed indicated by the signals from the sensors 24 and 25 is calculated, and the deviation is output to one of the duty solenoid pulps so that the deviation remains constant. The control signal will be subjected to feedback control. Further, when the controller 20 determines in step S2 that the operating state belongs to the lock-up region (3), the controller 20 performs step S2.
At step 15, normal lockup control is executed.

In this embodiment, the function used for feedforward control is set in two ways, one for large acceleration and one for small acceleration, but the invention is not limited to this.

(Effects of the Invention) As described above, according to the present invention, when the operating state of the engine is in the slip region, the lock-up clutch is fed so that the lock-up clutch is fully engaged at the engagement timing predicted by the engagement timing predicting means. Since the engagement force is gradually increased by forward control, the lock-up clutch is smoothly engaged without compromising control stability, and the amount of slip decreases as the engagement force increases. Therefore, fuel efficiency is also improved.

[Brief explanation of the drawing]

1 to 12 show embodiments of the present invention. FIG. 1 is a diagram showing the structure of a torque converter and its hydraulic circuit, FIG. 2 is a control system diagram of the converter, and FIG. 3 is a diagram showing the control operation. Fig. 4 is a map showing the control region, Fig. 5 is a map of the initial duty value using vehicle speed and throttle opening as parameters during large acceleration, and Fig. 6 is a map showing the control area.
The figure also shows a map of the lock-up arrival time using vehicle speed and acceleration as parameters, Fig. 7 is a characteristic diagram showing an example of setting the first leap number f+ (t) using the above map, and Fig. 8 shows a characteristic diagram at the time of large acceleration. A time chart of the slip amount of the lock-up clutch. Figure 9 is a map of the initial duty value using vehicle speed and throttle opening during small acceleration as parameters. Figure 10 is a map of reaching lock-up using vehicle speed and acceleration as parameters. A time map, Fig. 11 is a characteristic diagram showing an example of setting the second function f1 (t) using the above map, and Fig. 12 is a time chart of the slip amount of the mouth/tsukamp clutch during small acceleration. . ■... Torque converter (fluid coupling), 2... Engine output shaft (input member), 8... Turbine shaft (
output member), 10... lock-up valve, 19...
・Duty inlenoid valve, 20... Controller (fastening timing prediction means, feed forward control means, 2
1...Vehicle speed sensor (vehicle speed detection means). e No. 2 ■ @ 4 Figure No. 51! S ll5-11 Figure shouting lock (?) Time (11'2

Claims (1)

[Claims] (1) A lock-up clutch that is installed in a fluid coupling installed in the power transmission path from the engine and directly connects the input and output members of the coupling, and a fastening force variable means that changes the fastening force of the lock-up clutch. is provided, and the fluid coupling engagement force control device is configured to engage the lock-up clutch from a non-engaged state to a slip state, wherein when the operating state of the engine belongs to the slip region, the lock-up clutch is engaged in the engagement region. engagement timing prediction means for predicting when the transition will occur, and the engagement force variable means for operating the engagement force variable means to gradually increase the engagement force so that the lock-up clutch is fully engaged at the engagement timing predicted by the means. 1. A fastening force control device for a fluid coupling, comprising: a feedforward control means.