JPH03260466A - Slip control device for fluid coupling - Google Patents

Abstract

PURPOSE:To prevent poor performance of vehicle acceleration and prevent torque shock by feedback controlling the engagement force so that the difference in the number of revolutions between an input member and an output member lies within the specified extent, and controlling the engagement force of a lockup clutch at the time of deceleration under the initially set value at the time of acceleration. CONSTITUTION:The engaging condition of a lockup clutch 8 is put under feedback control by a control unit 13, which is fed with signals from an engine revolution sensor 14 and a turbine revolution sensor 15. The control unit 13 controls so that the difference in the number of revolutions between the input and output member of a fluid coupling lies within the specified value. The engagement force of lockup clutch is set to the specified initial value when the feedback is started at accelerating, and the engagement force of the lockup clutch when feedback is started at decelerating is so controlled as to become below the mentioned initially set value. This prevents poor performance of vehicle accelerating as well as generation of torque shock.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a control device for a fluid coupling, and in particular, it is provided with a fastening force control means for controlling the fastening force of a lock-up clutch of a fluid coupling, and is equipped with a fastening force control means for controlling the fastening force of a lock-up clutch of a fluid coupling. In each predetermined operating range, the fastening force is feedback-controlled to control the slip of the mouth, sofa, and pump clutches so that the rotational speed difference between the input member and the output member of the fluid coupling is within a predetermined value. The present invention relates to a slip control device for a fluid coupling that initially sets the engagement force of a pull-up clutch to a predetermined value at the start of the engagement force feedback control.

(Prior Art) The torque converter used in the automatic transmission of an AT vehicle has a torque increasing effect, a shift shock absorbing effect, etc. in order to prevent deterioration of engine fuel efficiency due to so-called slippage of the torque converter. A lock-up clutch that directly connects input and output members is generally used in predetermined operating ranges where this is not required.

However, when the lock-up clutch is engaged and the input/output components of the torque converter are directly connected, engine vibrations are directly transmitted to the transmission, especially in the low engine speed range, resulting in a problem in which the comfort of the vehicle deteriorates. arise.

As a solution to this problem, for example, Japanese Patent Application Laid-open No. 57-
As disclosed in Japanese Patent No. 33253, a lock-up clutch is provided with a fastening force control means for controlling the fastening force of the lock-up clutch,
In a predetermined low rotation range, the lock-up clutch is controlled to be in a slip state by feedback-controlling the engagement force of the lock-up clutch so that the rotation speed difference between the input member and the output member of the torque converter is within a predetermined value; Thereby, there is a torque converter control device that is configured to prevent engine vibration from being transmitted to the transmission while preventing deterioration in fuel efficiency when the lock-up clutch is completely released.

As mentioned above, conventionally, the control device performs feedback control on the engagement force of the lock-up clutch in a predetermined low rotation region, that is, in a low vehicle speed region, during acceleration and deceleration to perform slip control of the lock-up clutch. In addition, when starting feedback control of the lock-up clutch engagement force during acceleration, the lock-up clutch engagement force is set to a predetermined initial value in order to reduce torque shock while ensuring the necessary acceleration. It was common to set it to a value.

(Problem to be Solved by the Invention) When the lock-up clutch is put into a slip state and the vehicle is decelerated, the engine rotation speed and the rotation speed of the input member of the torque converter rapidly decrease. Since a driving torque based on inertial force acts, the rotational speed of the member does not decrease rapidly. Therefore, the difference in rotational speed between the input and output members of the torque converter increases.

This rotation speed difference between the input and output members becomes particularly large in a low vehicle speed region where the inertial force of the vehicle body is small and the reverse driving force from the output member of the torque converter to the input member is small.

For this reason, in conventional torque converter control devices, in order to keep the increased rotational speed difference between the human output members within a predetermined value during deceleration, the lock-up clutch engagement force or the lock-up clutch engagement force during acceleration is applied. In some cases, the feedback control is performed to a much higher value than the initial value when starting the feedback control, and when the transition from deceleration to acceleration occurs, the lock-up clutch may be engaged at the initial stage of feedback control during acceleration. Until the force is corrected from a value higher than the initial setting value to the initial setting value, there is a problem in that the vehicle has poor acceleration and torque shock occurs.

Therefore, an object of the present invention is to provide a fastening force control means for controlling the fastening force of a lock-up clutch of a fluid coupling, and to control the rotation of the manual member and the output member of the fluid coupling in predetermined operating ranges during acceleration and deceleration. The lock-up clutch is controlled to slip by feedback controlling the lock-up clutch so that the difference in number is within a predetermined value, and when starting feedback control of the lock-up clutch engaging force during acceleration, the lock-up clutch engaging force is In a slip control device for a fluid coupling, which is now set to a predetermined initial value, the vehicle The object of the present invention is to provide a control device that can prevent poor acceleration and torque shock.

(Means for Solving the Problems) In order to solve the above problems, the present invention is provided with a fastening force control means for controlling the fastening force of a lock-up clutch of a fluid coupling, and is provided with a fastening force control means for controlling the fastening force of a lock-up clutch of a fluid coupling, and a predetermined operation is performed during acceleration and deceleration. In this region, the engagement force is feedback-controlled so that the rotational speed difference between the input member and the output member of the fluid coupling is within a predetermined value, and when starting the lock-up clutch engagement feedback control during acceleration, In a fluid coupling slip control device that sets the engagement force of a lock-up clutch to a predetermined initial value, during deceleration, the engagement force of the lock-up clutch is controlled to be equal to or less than the initial setting value during acceleration. Provided is a slip control device for a fluid coupling, characterized in that it is equipped with a means for controlling the slip of a fluid coupling.

In a preferred embodiment of the present invention, the means for controlling the engagement force of the lock-up clutch during deceleration to be equal to or less than the initial setting value during acceleration is configured to control the lock-up clutch in a low vehicle speed region below a predetermined vehicle speed. This means controls the fastening force so that it is equal to or less than the initial setting value during acceleration.

(Function) As described above, in the present invention, a means is provided to control the engagement force of the lock-up clutch during deceleration so that it is equal to or less than the initial setting value during acceleration, so that deceleration changes to acceleration. At this time, the engagement force of the lock-up clutch, which is feedback-controlled during deceleration, is close to the initial setting during acceleration. Therefore, when the feedback control of the lock-up clutch engagement force during deceleration is shifted to the feedback control of the lock-up clutch engagement force during acceleration, poor acceleration of the vehicle and torque shock do not occur.

In addition, by providing a means to control the engagement force of the lock-up clutch to be less than the initial setting value during acceleration in a low vehicle speed region below a predetermined vehicle speed during deceleration, it is possible to By making the vehicle speed range in which the rotation speed difference is controlled within a predetermined value as wide as possible, deterioration of fuel efficiency can be prevented.

(Example) The present invention will be described in detail below based on the accompanying drawings.

In FIG. 1, 1 is a torque converter provided with a control device according to an embodiment of the present invention. The torque converter 1 is fixedly installed on one side of a case 4 connected to an output shaft 3 of an engine 2, and includes a pump 5 that rotates integrally with the engine output shaft 3, and the other side of the case 4 facing the pump 5. A turbine 6 is disposed rotatably with respect to the case 4 on the side of the case 4 and is rotationally driven via hydraulic oil by the rotation of the pump 5, and a turbine 6 is interposed between the pump 5 and the turbine 6. The engine includes a stator 7 that increases torque when the ratio of the turbine rotation speed to the pump rotation speed is below a predetermined value, and a lock-up clutch 8 interposed between the turbine 6 and the case 4. The output is output from the rotating shaft 9 of the turbine 6 and is input to the gear transmission mechanism 1O, and the lock-up clutch 8 is connected to the turbine shaft 9.
When the engine is fastened to the case 4, the engine output shaft 3 and the turbine shaft 9 are directly connected through the case 4.

Hydraulic oil supplied from a pump (not shown) is introduced into the lock-up clutch 8 via an oil path 11, and the oil pressure of the hydraulic oil is controlled by a solenoid I2 installed in the middle of an oil path II. Lockup clutch 8
The fastening state between the case 4 and the case 4 is controlled.

A control unit 1 basically consisting of a CPU, ROM, and RAM for controlling the engagement state of the lock-up clutch.
3, the control unit 13 receives an engine rotation signal and a turbine rotation signal from an engine rotation sensor 14 and a turbine rotation sensor 15, respectively, and a throttle opening signal and a turbine rotation signal from a throttle opening sensor and a vehicle speed sensor (not shown), respectively. A vehicle speed signal is input. Further, the control unit 13 outputs a control signal for controlling the operation of the solenoid 12.

Further, the control unit 13 receives a human input from a brake sensor (not shown) as a brake signal indicating the state of depression of the brake, and further receives a gradient signal indicating the gradient state of the road surface from the gradient sensor.

The operation of the control device according to this embodiment configured as described above will be explained below. Note that in the following, S represents a control step.

In this control device, the driving range A shown in FIG. 2, that is, the vehicle speed is Vl4. The input/output member of the torque converter 1, that is, the engine output shaft 3, is in the acceleration region where the throttle opening degree is 0 to θ at CV2 > Vl) and the deceleration region where the throttle opening is fully closed at the driving region B1, that is, the vehicle speed is V to V2. The engagement force of the lock-up clutch 8 is feedback-controlled, and the lock-up clutch 8 is controlled to slip so that the difference in rotational speed between the turbine shaft 9 and the turbine shaft 9 is within a predetermined value. Further, in the operating range C, the lock-up clutch 8 is completely engaged, and in the operating range, the lock-up clutch 8 is disengaged.

Details of the feedback control of the lock-up clutch engagement force described above will be explained based on the flowchart of FIG. 3.

Control starts when the engine starts.

The control unit 13 first reads a vehicle speed signal, a throttle opening signal, and a gradient signal (S1), and determines whether the driving region is in region A in FIG. 2 (S2). The driving area is the second
If the operating range is in region A in the figure, the control unit 13 further determines whether or not the operating region was in region A in FIG. 2 in the previous control loop (S3). If the operating region was not in region A in FIG. 2 in the previous control loop, that is, immediately after entering region A from regions B to D in FIG. 2, the control unit 13 controls the solenoid 12. send a signal,
The initial value of the lock-up clutch engagement force T is a predetermined value T. and starts feed control of the lock-up clutch engagement force in the A region, that is, the acceleration region (S4).
. If the operating region was in the A region in Fig. 2 in the previous control loop, that is, if the feedback control of the lock-up clutch engagement force in the A region has already been started, the initial control is performed in step S4. Value T. The feedback control of the lock-up clutch engagement force T that was started under (S5) is continued. The above control prevents fuel consumption from deteriorating in the A region, prevents engine vibration from being transmitted to the transmission, and prevents torque shock from occurring when starting feedback control in the A region.

If the operating region is not in region A of FIG. 2, the control unit 13 determines whether the operating region is in region B of FIG. 2 (86), and the operating region is in region B of FIG. In this case, the vehicle speed V is further set to a predetermined value V, , (V, , <V2)
It is determined whether or not the value is below (S7). Vehicle speed V is a predetermined value V
If rl l fi or less, the control unit 13 engages the lock-up clutch in order to prevent torque shock from occurring when transitioning from area B to area A, that is, when changing from deceleration to acceleration. Maximum allowable force T
4. ．． is the initial value T of the lock-up clutch engagement force T in feedback control in region A. After setting it to (
S8), feedback control of the lock-up clutch engagement force in the B region, that is, the deceleration region is performed (S9).

With the above control, the vehicle speed in region B is set to V. In a low vehicle speed region of 11 or less, deterioration of fuel efficiency is prevented and transmission of engine vibration to the transmission is prevented.

Furthermore, in the feedback control in this region, the lock-up clutch engagement force does not exceed the initial value T0 of the lock-up clutch engagement force T in the feedback control in the A region, and in the deceleration region, the input/output member of the torque converter 1 Taking into account that the difference in rotational speed between No defects or torque shocks will occur. In addition, since the above control is performed only in the low vehicle speed range where torque shock is particularly likely to occur when transitioning from deceleration to acceleration, the deterioration of fuel efficiency due to setting an upper limit on the lock-up clutch engagement force is avoided. can be kept to a minimum.

In addition, in this example, V Shock can be prevented.

If the operating range is not in the A range of FIG. 2 and also not in the B range, the control unit 13 sends a control signal to the solenoid 12 to fully engage the lock-up clutch in the C range and to lock it in the D range. Release the up clutch (step 10).

Note that the control device according to this embodiment is designed to feedback control the engagement force of the lock-up clutch so that the driver can obtain the feeling of deceleration requested by the driver on a downhill slope.

On a downhill slope, if the vehicle speed at the time the accelerator changes from ON to OFF and the vehicle speed at that point when the brake changes from ON to OFF are maintained, the driver feels that he or she has achieved the desired feeling of deceleration. do.

By the way, as a result of intensive research, the inventor has found that the gradient of a slope and the engagement force of the lock-up clutch required to maintain a predetermined vehicle speed on the slope have a correlation as shown in Fig. 3. We have obtained the following knowledge.

Therefore, in the control device according to the present embodiment, based on the above knowledge, the vehicle speed at the time when the accelerator changes from ON to OFF on a downhill slope, and the time when the brake changes from ON to OFF on a downhill slope. The engagement force of the lock-up clutch is feedback-controlled to maintain the vehicle speed.

That is, in step St of FIG. 2, the control unit 13 reads the slope signal (sl) in addition to the vehicle speed signal and the throttle opening signal, and in step S7, the control unit 13 reads the slope signal (sl), and in step S7, the vehicle speed V
is a predetermined value V. If the slope α exceeds the predetermined value α□8
It is determined whether it is less than 7 (Sll).

If the slope α is greater than the predetermined value α□, the control unit 13 determines that it is impossible to maintain the vehicle speed constant by controlling the engagement force of the lock-up clutch because the slope is large, and performs the control in step S8. to move to.

If the gradient α is less than the predetermined value α4.3, the control unit 1-1
Step 3 further determines whether or not the vehicle was in the operating region or region B in the previous control loop, the vehicle speed V exceeded a predetermined value V□1o, and the slope α was less than a predetermined value α41 (S
I2).

If the above conditions were not met in the previous control loop, that is, if the vehicle had just reached a slope where the vehicle speed could be kept constant by controlling the engagement force of the lock-up clutch, the control unit 13 further controls the braking. The signal is read and it is determined whether the brake has changed from ON to OFF (S13).

When the brake is turned from ON to OFF, the control unit 13 reads the vehicle speed again (S14), and uses the vehicle speed (2) to determine the above-mentioned speed based on the correlation diagram of FIG. Find the lock-up clutch engagement force T required to maintain the vehicle speed V, and calculate the engagement force T,
Feedback control of the lock-up clutch engagement force should be started using the initial value as 515), but if this is not possible,
Using the vehicle speed V read in step SL and based on the correlation diagram of FIG. 3 written in the ROM, find the lock-up clutch engagement force T required to maintain the vehicle speed V, Feedback control of the lock-up clutch engagement force is started using the engagement force T as an initial value (
S l 6).

In the previous control loop, the operating region was in region B, the vehicle speed V exceeded the predetermined value Vffi+n, and the slope α
is less than the predetermined value α428, that is, if the feedback control of the lock-up clutch engagement force to maintain the vehicle speed constant has already been started, the initial value T, , T
The feedback control of the lock-up clutch engagement force T, which was started under , is continued (S17).

The above control provides the feeling of deceleration required by the driver on a downhill slope.

Although the present invention has been described in detail above, it goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made within the scope of the invention as set forth in the claims.

(Effects) As can be seen from the above description, in the present invention, a means is provided to control the engagement force of the lock-up clutch during deceleration so that it is equal to or less than the initial setting value during acceleration. When the vehicle starts accelerating, the lock-up clutch engagement force is feedback-controlled during deceleration, or the value is close to the initial setting during acceleration. Therefore, when the feedback control of the lock-up clutch engagement force during deceleration is shifted to the feedback control of the lock-up clutch engagement force during acceleration, poor acceleration of the vehicle and torque shock do not occur.

In addition, by providing a means to control the engagement force of the lock-up clutch to be less than the initial setting value during acceleration in a low vehicle speed region below a predetermined vehicle speed during deceleration, it is possible to Deterioration of fuel efficiency can be prevented by widening the vehicle speed range within which the rotational speed difference is controlled within a predetermined value.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a torque converter provided with a slip control device for a fluid coupling according to an embodiment of the present invention. FIG. 2 is a map showing the control area. FIG. 3 is a flow chart of the operation of the control device of FIG. FIG. 4 is a correlation diagram between the slope and the lock-up clutch engagement force required to maintain a predetermined vehicle speed on the slope. DESCRIPTION OF SYMBOLS 1... Torque converter, 6... Turbine, 8... Lock-up clutch, 12... Solenoid, 13... Control unit. Fig. 4 Fastening force 447-

Claims (2)

[Claims] (1) Equipped with a fastening force control means that controls the fastening force of the lock-up clutch of the fluid coupling, and the rotational speed difference between the input member and the output member of the fluid coupling is set to a predetermined value in each predetermined operating range during acceleration and deceleration. The lock-up clutch is controlled to slip by feedback-controlling the lock-up clutch so that the lock-up clutch is within a predetermined initial value at the time of starting the feedback control of the lock-up clutch engaging force during acceleration. The slip control device for a fluid coupling that has been set is characterized by comprising means for controlling the engagement force of the lock-up clutch during deceleration so as to be equal to or less than the initial setting value during acceleration. Slip control device for fluid couplings. (2) The means for controlling the engagement force of the lock-up clutch during deceleration to be equal to or lower than the initial setting value during acceleration, is configured to control the engagement force of the lock-up clutch during acceleration in an operating range below a predetermined vehicle speed. The slip control device according to claim 1, characterized in that the slip control device is a means for controlling the slip control so that the slip control device is controlled so that the slip control device is controlled so that the slip control device becomes equal to or less than an initial setting value of the slip control device.