JPH0389072A - Slip control device for fluid coupling - Google Patents

Abstract

PURPOSE:To obtain desirable running performance at the time of accelerating at a high speed stage in a hysteresis region by correcting the locking force of a lock-up clutch according to the speed change stage in the hysteresis region of a speed change line set with plural speed change stages. CONSTITUTION:A locking force control means C controls the locking force of the lock-up clutch B of a fluid coupling A in the specified slip control region judged by a region judging means E, thus obtaining the specified slip state. At this time, in the hysteresis region of a speed change line set with plural speed change stages, the locking force of the locking force control means C is corrected by a correcting means D according to the speed change stage, for instance, to increase slip quantity in the high speed stage. Running performance apt to lack at the time of accelerating at the high speed stage can be thus ensured, as well as the increase of fuel consumption at the low speed stage can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a slip control device for a fluid coupling that controls the slip state of the lock-up clutch in a fluid coupling provided with a lock-up clutch.

(Prior art) In general, in a fluid coupling such as a torque converter equipped with a lock-up clutch, the lock-up clutch is released at low vehicle speeds when engine torque fluctuations are transmitted to the wheels and vehicle ride comfort deteriorates. The converter operates in a converter state with a torque increasing function and a torque fluctuation absorbing function. At high vehicle speeds, where engine torque fluctuations are not a problem, the lock-up clutch is engaged and the input and output shafts are directly connected, and the fluid coupling The system operates in a lock-up state, which reduces energy loss due to slippage and improves fuel efficiency.

In addition, in a fluid coupling equipped with a lock-up clutch as described above, in the region of low vehicle speed and low load, it is preferable to set the lock-up state to the converter state from the point of view of improving fuel efficiency. This torque fluctuation is directly transmitted to the wheels, causing vibrations in the vehicle body.

Therefore, for example, as disclosed in Japanese Patent Application Laid-open No. 57-33253, lock-up clutches have been proposed to improve fuel efficiency to some extent and reduce the transmission of torque fluctuations to suppress gear shift shock and vehicle body vibration. A slip control device is known that controls the converter to a predetermined slip state intermediate between a lock-up state and a converter state, thereby producing a predetermined rotation difference between input and output.

The control in the above-mentioned slip control device adjusts the pressure difference between the pressure in the engagement chamber that acts in the direction of engagement of the lock-up clutch and the pressure in the release chamber that acts in the direction of release, so that the lock-up clutch is brought into a predetermined slip state. A mechanism that controls differential pressure is adopted. Then, by controlling the differential pressure, the rotational speed at the input end of the lock-up clutch and the rotational speed at the output side are set to a predetermined rotational speed difference, thereby achieving both fuel efficiency and running performance.

For specific slip control, the slip area is set based on manifold negative pressure (load) and engine speed,
Feedback control is performed so that the target slip amount is achieved.

(Problem to be Solved by the Invention) However, when a shift line is set within the region where the slip control is performed, a predetermined hysteresis region is set for this shift line between upshifts and downshifts, Even in the same driving condition, the gear position is set to be different when shifting up and downshifting. In such a hysteresis region where a plurality of gears are set, if the slip amount is set with a single characteristic regardless of the gears as in the previous example, the driving performance,
It is difficult to set a setting that satisfies both fuel efficiency and vibration characteristics.

In other words, if slip control is performed mainly in low gears,
In order to improve fuel efficiency by setting a relatively small amount of slip that provides sufficient acceleration, that is, torque multiplication in low gear, when the gear shifts to high gear with this amount of slip, the amount of slip is small. Driving performance will deteriorate. For example, when shifting up, the vehicle speed and throttle opening range where good acceleration can be obtained in the lower gear,
When downshifting to a higher speed gear in the same driving range, if you continue to decelerate, there is no problem with the slip amount matching the lower gear, but from this state the throttle opening is opened and the speed is accelerated. When doing so, there is a risk that the driving force may be insufficient until the gear is shifted to the lower speed side, causing a problem in which good acceleration performance cannot be obtained. Further, if the slip amount is set to a value that ensures the driving performance at the high speed, the fuel efficiency at the low speed will decrease.

Therefore, in view of the above circumstances, it is an object of the present invention to provide a slip control device for a fluid coupling that performs good slip control at each gear stage in the hysteresis region of the shift line in the slip control region. .

(Means for Solving the Problems) In order to achieve the above object, the slip control device for a fluid joint of the present invention, as shown in the basic configuration in FIG. A fluid coupling A having a converter function for transmitting torque includes a lock-up clutch B that can directly connect an input element and an output element.

The engagement force of this lock-up clutch B is controlled by engagement force control means C. In a slip control region where the operating state is a predetermined slip control region, the lock-up clutch B adjusts the differential pressure between the pressure in the engagement chamber that acts in the engagement direction and the pressure in the release chamber that acts in the release direction, for example. is controlled to a predetermined slip state. In addition, in the slip control region where the slip control is performed, there is a hysteresis region of the shift line where a plurality of gears are set,
Head mounting determination means E for determining this hysteresis region is provided.

A fastening force correcting means is provided which receives the signal from the region determining means E and corrects the fastening force of the lock-up clutch B within the hysteresis region. The fastening force correction means is configured to correct the fastening force by the fastening force control means A so that the amount of slip becomes larger in high speed gears than in low speed gears according to the gear speed in this hysteresis region.

(Function) In the slip control device for a fluid coupling as described above, when a predetermined slip control region is reached, the engagement force of the lock-up clutch is controlled by the engagement force control means to obtain a predetermined slip state. In the hysteresis region of the shift line where the gear is set, the tightening force of the engagement force control means is corrected by the correction means so that the amount of slip in the high gear increases, for example, in accordance with the gear. In addition to ensuring the driving performance that is lacking during acceleration, the reduction in fuel efficiency at low gears is suppressed, and good slip control is achieved at all gears.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an example of a slip control device for a fluid coupling together with a power plant of a vehicle to which it is applied.

The power plant includes an engine body 10 and an automatic transmission 20
Each cylinder in the engine body 10 (four cylinders) is supplied with an air-fuel mixture formed by intake air from an intake passage 16 in which a throttle valve 14 is disposed and fuel injected from a fuel injection valve. The generated torque is transmitted to the wheels via a power transmission path including the automatic transmission 20.

In the engine main body 10, fuel supply is stopped when the engine speed is above a predetermined value and the throttle is fully closed during deceleration, and when the engine speed becomes less than the predetermined value from this fuel cut state, fuel supply is restarted. Deceleration fuel control is performed.

The automatic transmission 20 includes a fluid coupling 24 (torque converter), a multi-stage vehicle type transmission mechanism 26, shift control solenoid valves 1 to 5 for forming hydraulic pressure used for controlling these, and lock-up control. It has a hydraulic circuit section 30 equipped with a solenoid valve 6 for use and a solenoid valve 7 for pressure regulation.

The fluid coupling 24 includes an input shaft 25 and an output shaft 39 that rotate together with the output section 10a of the engine body 10, as shown in FIG. A converter section 27 that transmits torque via fluid, and a lock-up clutch 21 that transmits torque in a directly coupled state or in a slip state are arranged in parallel between the two. The converter section 27 includes a pump impeller 34 as an input element fixed to a drive plate 32 that rotates integrally with the human power shaft 25, and an output shaft 3.
The lock-up clutch 21 includes a turbine runner 36 that rotates together with the turbine runner 9, a stator 35 between the two, and a one-way clutch 38.
The clutch plate 22 is connected to the clutch plate 22 via a coil spring 23a.

Due to the arrangement of the lock-up clutch 21, a release chamber 43 is formed on the back side of the clutch plate 22 between it and the drive plate 32, and a fastening chamber 44 is formed on the opposite side. The release chamber 43 has a connection from the hydraulic circuit section 30 to the Uraji 42.
Hydraulic pressure for disengaging the clutch plate 22 is supplied through the clutch plate 22 , and hydraulic pressure for engaging the clutch plate 22 is supplied to the engagement chamber 44 through the simplification 41 . The lock-up clutch 21 is in a lock-up state in which hydraulic pressure is supplied to the engagement chamber 44 to directly connect the pump impeller 34 and the turbine runner 36, and in a lock-up state in which hydraulic pressure is supplied to the release chamber 43 to directly connect the pump impeller 34 and the turbine runner. 36 is not engaged (converter state)
Further, when hydraulic pressure is supplied to both the engagement chamber 44 and the release chamber 43 and the differential pressure ΔP is within a predetermined range, relative rotation between the pump impeller 34 and the turbine runner 36 is allowed. A slip condition occurs, and the differential pressure Δ
As P becomes larger, the amount of slip decreases and approaches the lock-up state. Incidentally, the fastening chamber 44 is connected to an oil cooler 48 through a pipe 47 in which a check valve 46 is disposed.

The parts of the hydraulic circuit section 30 that are involved in controlling the operation of the fluid coupling 24 include a lock-up shift valve 51, a lock-up pressure regulating valve 52, and the lock-up control solenoid valve 6.
and a pressure regulating solenoid valve 7. The lock-up shift valve 51 is divided into a first spool 56 and a second spool 57 for hydraulic adjustment to ports a, d, and h.
The operation of the port switches ports b, c, and e-g to open and close communication and to drain. Further, the lock-up pressure regulating valve 52 switches communication opening/closing and draining of ports j-m by the operation of the spool 60 accompanying oil pressure adjustment to ports i and n.

In the lock-up shift valve 51, the oil pressure of the oil pump 45 is made constant by the constant pressure forming part 50 and regulated by the pressure regulating solenoid valve 7, and the oil pressure is supplied to the port a, and the first spool 56 and second spool 5
The hydraulic pressure reduced by the constant pressure forming section 50 is supplied to the port d between the oil pump 45 and the port 7, and the hydraulic pressure of the oil pump 45 regulated by the lock-up control solenoid valve 6 is supplied to the port h. The hydraulic pressure supply to the joint 24 is switched to switch between a converter state, a lock-up state, and a slip state. In addition, the lock-up pressure regulating valve 5
2, the throttle pressure pt regulated by the throttle pressure forming section 61 in accordance with the throttle opening is supplied to the port i.
On the other hand, the duty control pressure Pd, which has been made constant in the constant pressure forming section 50 and regulated by the pressure regulating solenoid valve 7, is supplied to Bau)n, and the duty control pressure Pd is supplied to the connection chamber 4 of the fluid coupling 24.
This is to control slippage by adjusting the differential pressure ΔP between the release chamber 4 and the release chamber 43.

A description of the change in the state of the fluid coupling 24 due to the operation of the lock-up shift valve 51 and the lock-up pressure regulating valve 52 will be omitted here, but details thereof can be found in the specification of Japanese Patent Application No. 83-278609 filed by the same applicant. Please refer to

Further, as shown in FIG. 2, in order to control the operation of the hydraulic circuit section 30, the hydraulic circuit section 30 includes built-in solenoid valves 1 to 5 for speed change control, a solenoid valve for lock-up control 6, and a solenoid valve for pressure regulation. 7, drive signal Ca-C
A control unit 100 is provided that outputs each g.

This control unit 100 includes a throttle valve 1
4, a detection signal St obtained from a throttle opening sensor 81 that detects the opening Th, a detection signal SV obtained from a vehicle speed sensor 82 that detects the vehicle speed V, and a shift position sensor 83 that detects the operating position of the shift lever. The obtained detection signal Ss and the engine rotation speed Ne (manual rotation speed)
The detection signal Sn obtained from the engine rotation speed sensor 84 that detects the turbine rotation speed of the turbine runner 36 (
A detection signal Sm obtained from a turbine rotational speed sensor 85 that detects the output rotational speed), a detection signal Sa obtained from an accelerator sensor 86 that detects the amount of depression of the accelerator pedal, and a detection signal Sa obtained from the accelerator sensor 86 that detects the amount of depression of the accelerator pedal. A detection signal Su obtained from an oil temperature sensor 87 that detects the temperature and a detection signal sb obtained from a brake sensor 88 that detects the amount of depression of the brake pedal are supplied to the automatic transmission 2.
Other detection signals Sx necessary for the control of 0 are also supplied.

The control unit 100 controls the speed change in the automatic transmission 20 and the operation of the lock-up clutch 21 with desired characteristics based on the various detection signals described above.

Automatic transmission 20 by this control unit 100
When controlling the speed change and the operation of the lock-up clutch 21, the control range is determined from the shift pattern shown in FIG. 4, which is mapped and stored in the built-in memory of the control unit 100.

This shift pattern has the throttle opening Th on the vertical axis and the vehicle speed V on the horizontal axis, and the regions of each gear stage at the time of upshifting are upshift shift lines Ua and Ub.

It is indicated by Uc, and when the range changes, it is a shift-up shift.On the other hand, the range of each gear during downshifting is indicated by downshift shift lines Dd, De, and Df, and when the range changes, it is a shift-up shift. It's time to shift gears. In addition, the inside of the lock-up operating line Lg (4th gear) and Li (3rd gear), which are set in the region of low slot small opening at relatively high vehicle speeds, is the lock-up region when transitioning to the lock-up state. The release of is the lock-up release line Lh (
4th speed) and Lj (3rd speed), and the time of region change is the time of activation and release control of the lock-up state. Furthermore, the inside of the slip control execution line Rj, which is set in the area of relatively low vehicle speed and low throttle opening, is the slip control area, and slip control is started when the line shifts to this area, and is set outside of this area. The slip control is controlled to be canceled when the vehicle moves to a region outside the slip control release line Rk.

With the above shift pattern, upshift shift lines Ua, Ub, Uc and downshift shift lines Dd, De, Df are applied to the slip control region, and within the hysteresis region formed between both shift lines, the same driving Even in this state, a plurality of gears are set.

Then, the control unit 100 controls the above-mentioned shift line U.
If it is detected from the determination of a-Uc and Dd-Df that a shift-up condition or a shift-down condition is established, a drive signal Ca-Ce is selectively sent out to switch the gear stage in the transmission mechanism 26, Performs speed change control.

Further, if neither the lockup operating condition nor the slip control condition described below is satisfied, the supply of drive signals Cf and Cg to the lockup control solenoid valve 6 and the pressure regulating solenoid valve 7 is stopped. As a result, both the solenoid valves 6.7 are closed, the lock-up shift valve 51 and the lock-up pressure regulating valve 52 are in the position shown by the solid line in FIG. is supplied to the fastening chamber 4.
4 of oil pressure is discharged to the oil cooler 48, the lock-up clutch 21 is released, and the torque is transmitted by the converter section 27.

Further, when the lock-up operating condition is satisfied, the drive signal Cf is supplied to the lock-up control solenoid valve 6 to open it, and the pressure regulating solenoid valve 7 is closed by stopping the drive signal Cg.

As a result, the lock-up shift valve 51 is at the position indicated by the chain line.
The lock-up pressure regulating valve 52 is at the position indicated by the solid line, and the hydraulic pressure regulated by the four regulator valves is supplied to the engagement chamber 44, while the hydraulic pressure in the release chamber 43 is discharged to the oil pan.
The lock-up clutch 21 is in a fastened state and is in a lock-up state in which input and output are directly connected.

On the other hand, when the throttle opening Th and the vehicle speed ■ are in the slip control region and the steady slip control condition is established, when the shift up condition is established and the shift slip control condition is established, and when the throttle opening is fully open and the engine is rotating When the deceleration slip control condition is satisfied when the number is greater than a predetermined value, the drive signal Cf is supplied to the lock-up control solenoid valve 6 to open it, and the pressure regulating solenoid valve 7 is supplied with a pressure of 20% or more. It is operated to a predetermined opening degree by supplying a drive signal Cg having a duty value d.

As a result, in the lock-up shift valve 51, the first spool 56 is at the position shown by the solid line, and the second spool 57 is at the position shown by the chain line, and the lock-up pressure regulating valve 52 is set to the position shown by the solid line, and the lock-up pressure regulating valve 52 is set to the position indicated by the throttle pressure pt of the port li and the duty control pressure Pd (duty value) of the port n. The hydraulic pressure regulated by the four regulator valves is supplied to the engagement chamber 44, and the release chamber 43 is supplied with the hydraulic pressure regulated by the four regulator valves. is supplied with a hydraulic pressure reduced according to the duty value, and the lock-up clutch 21 inputs a slip amount ΔN (input/output rotation difference) according to a differential pressure ΔP obtained by subtracting the hydraulic pressure in the release chamber 43 from the hydraulic pressure in the engagement chamber 44. A slip state is created between the shaft 25 and the output shaft 39.

In this case, the differential pressure ΔP is calculated from the throttle pressure pt, the duty control pressure Pd, and the biasing force Fa of the spring 62. If cl and c2 are constants, ΔP=CI (P
tPd)+Fa/Cz, and the differential pressure ΔP is defined by the throttle pressure pt and the duty control pressure Pd. Then, the throttle pressure pt is the throttle opening T
h, the duty control pressure Pd is formed to have the characteristics shown in FIG. 5, for example, and the duty control pressure Pd is formed to have the characteristics shown in FIG. 6, for example, with respect to the duty value d of the drive signal Cg. is formed. As a result, the differential pressure ΔP becomes larger as the throttle opening Th and the duty value d become larger, as shown in FIG. .

Furthermore, the transferable torque Ts, which is the maximum torque that can be transferred from the input shaft 25 to the three output shafts when the lock-up clutch 21 is engaged, is calculated by the friction coefficient μ of the clutch plate 22, the effective radius r, and the engagement area A. On the other hand, it can be expressed as TsmΔP・μ・r−A, and the larger the differential pressure ΔP is, the larger the value becomes. The input torque Ti of the fluid coupling 24 is equal to the engine generated torque Te transmitted to the human power shaft 25, and if it is larger than the transmittable torque Ts, the input/output rotation difference ΔN will occur. The relationship between the above-mentioned human torque Ti and the input/output rotational difference ΔN is as shown in Fig. 8 when the operating bolt temperature is, for example, 90°C and the differential pressure ΔP is set to 1 to 4 kg/cm2 as a parameter. Become.

From the above, when slip control is performed on the lock-up clutch 21 in the fluid coupling 24, it is first detected that the steady slip control condition is satisfied even though the gear shift slip control condition is not satisfied. In this case, the target slip amount ΔN is determined according to the hysteresis region within the slip control region and its gear
(input/output rotation difference) is set. The slip amount ΔN is a predetermined rotational speed difference Δ between the input shaft 25 and three output shafts in the fluid coupling 24, which reduces energy loss and absorbs torque fluctuations generated by the engine.
N1 is set to, for example, 80 to 150 rpm, and is in a hysteresis region where a plurality of gears are set (in the example of FIG. 3rd gear hysteresis area, 3rd-4th gear hysteresis area between the upshift line Uc and the downshift line Df), the standard is based on the low speed side, that is, the state of the gear position at the time of upshifting. On the other hand, on the high speed side, that is, when changing gears during downshifting, the slip amount Nl is set as the target slip HN2-N, XCt, which is the reference slip ff1N, corrected by a correction coefficient Cf larger than 1 corresponding to the vehicle speed. A slip amount ΔN is set. As shown in FIG. 11, the correction coefficient Cf is set to have such a characteristic that it gradually decreases and approaches 1 as the vehicle speed V increases.

Lock-up clutch 21 to the target slip amount ΔN
In the control of the fastening force, at the start of the control, the value of the engine generated torque Te is detected based on the throttle opening Th and the engine speed Ne. In addition, the engine generated torque Te
The value of is obtained from a map set in advance according to the throttle opening Th and the engine speed Ne, and for example,
As shown in FIG. 9, the engine rotational speed Ne is plotted on the horizontal axis, and is shown by curves a1 to a6, respectively, with the throttle opening Th (178 to 6/8) as a parameter.

The transmission torque Tr is obtained by correcting the engine generated torque Te detected in this way by oil temperature. The value is set to a value smaller than 1 as the temperature becomes lower than 90° C., and the transmission torque Tr is obtained by multiplying the engine generated torque Te by this correction coefficient K.

Corresponding to the value of the transmission torque Tr, the value of the differential pressure ΔP is set so as to produce the slip amount ΔN set according to the hysteresis region and its gear as described above. The value of the differential pressure ΔP is read and set from a map shown in FIG. 8 in which the relationship between the input torque Ti, the slip amount ΔN, and the differential pressure ΔP is written. The value of the duty d of the drive signal Cg that generates the differential pressure ΔP is read from a map in which the relationship between the differential pressure ΔP and the duty d as shown in FIG. 7 is written, and is set as the initial value ya. be done. Then, the control unit 100 forms a drive signal Cg having a duty d set to the initial value ya, supplies it to the pressure regulating solenoid valve 7, and starts steady slip control.

After steady slip control is started in this way,
Deviation ΔNn between the actual slip amount and the target slip amount ΔN obtained by varying the turbine rotation speed at which the detection signal St is generated from the engine rotation speed at which the detection signal Sn is generated.
In order to bring the value of d close to zero, a new duty d is set by changing the value of duty d, a drive pulse signal Cg having the newly set duty d is formed, and it is supplied to the pressure regulating solenoid valve 7. By doing so, feedback control is performed so as to converge to the target slip amount ΔN. The value yn (n is a positive integer) of the duty d set during this feedback control is determined by the detection signal Sn and St is calculated based on the value of the engine rotational speed and the turbine rotational speed at which the storm occurs, and using the duty d value 'In-+ that has already been set at that time, as follows: yn■)'n-+ +ΔX . As shown in FIG. 10, ΔX in the above equation is set to take a stepwise larger value as the corrected calculation value Z calculated by Z-AXΔNn+BXΔN n-1 becomes larger. however,
In the above formula, ΔNn is the value of the slip amount deviation at that time,
ΔN n−, is the previous deviation value, and A and B are constants.

In this way, at the time when steady slip control is started, the value of the differential pressure ΔP at which the target slip amount ΔN occurs between the pump impeller 34 and the turbine runner 36 is set according to the input torque Ti of the fluid coupling 24, After that,
Since the differential pressure ΔP is feedback-controlled based on the deviation ΔNn between the actual slip amount due to the rotation speed difference between the pump impeller 34 and the turbine runner 36, the rotation speed of the pump impeller 34 and the turbine runner 36 changes from the start of steady slip control. Compared to the case where feedback control is started based on the difference, energy loss in the fluid coupling 24 and torque fluctuations generated by the engine are both absorbed between the pump impeller 34 and the turbine runner 36. The response delay time until the slip amount ΔN is obtained is shortened, thereby improving the fuel efficiency of the vehicle, and quickly and effectively performing steady-state slip control that suppresses vehicle body vibration. I can do it.

Furthermore, in the above-mentioned steady slip control, the target slip amount ΔN is set to a larger value in the high speed gear in the hysteresis region than in the low speed gear to reduce the engagement force of the lock-up clutch 21, and the target slip amount ΔN in the low speed gear is set to a value that is larger than that in the low speed gear. In order to improve
With this fastening force, when the gear is in a high speed gear, the amount of slip is small and the running performance deteriorates during operation in the hysteresis region. This problem is corrected by increasing the target slip amount ΔN and weakening the fastening force. In addition, the target slip amount ΔN within the hysteresis region is increased as the vehicle speed V decreases, thereby weakening the engagement force of the lock-up clutch 21, thereby preventing the occurrence of lock-up vibrations and sluggish acceleration, which are especially noticeable in the low vehicle speed region. At high speeds, the tightening force is increased to improve fuel efficiency.

In addition, the target slip amount Δ in the above hysteresis region
N may be set by correcting the low gear based on the high gear (or, the target slip amount ΔN may be changed in accordance with the vehicle speed V within the hysteresis region even in the low gear). .

Further, when it is detected that the shift slip control condition is satisfied, if the lock-up clutch 21 was in the slip engagement state immediately before that, the control unit 100 controls the value of the duty d of the drive signal Cg. is then set to the already set value '3/n-1, and a shift slip control is performed in which the drive signal Cg having the set duty d is supplied to the pressure regulating solenoid valve 7. On the other hand, when it is detected that the shift slip control condition is met, the lock-up clutch 2
If the lock-up clutch 21 is not in the slip-engaged state, that is, if the lock-up clutch 21 is in the tightened or released state, the manual operation of the fluid coupling 24 is performed in the same manner as when the steady slip control condition is established. Based on the torque Ti, the pump impeller 34 and the turbine liner 36
Set a differential pressure ΔP that produces a target slip amount ΔN between The shift slip control is performed until the shift operation is completed. Note that the time point at which the speed change operation is completed is, for example, when the value of the turbine rotation speed at which the detection signal St is generated is calculated based on the engine speed and the gear ratio in the gear position to be taken after the speed change. This is the point in time when the rotational speed matches the predicted value.

In this way, during shift slip control, the differential pressure ΔP
is set according to the input torque Ti of the fluid coupling 24 at the time of starting the shift slip control, so that it is suitable for the engine operating condition between the pump impeller 34 and the turbine runner 3, and the engine is It is possible to quickly generate a slip amount ΔN that can absorb the generated torque fluctuations. Thereby,
It is possible to prevent a large shift shock from occurring in the vehicle speed.

Note that when it is detected that the downshift condition has been established, the control unit 100 sends drive signals Cf and 2 to the lock-up control solenoid valve 6 and the pressure regulating solenoid valve 7, except when the engine is in a deceleration state. Stop supplying Cg. As a result, the lock-up clutch 21 is released.

Furthermore, if the control unit 100 detects that the deceleration slip control condition is established even though the lock-up operating condition is not established, the engine is in a state where torque is transmitted from the wheels, so the control unit 100 performs an experiment in advance. The torque transmitted from the wheels to the engine (hereinafter referred to as resistance torque) Te', which is calculated by E.g. and stored in the built-in memory according to the engine speed, corresponds to the engine speed at that time. Read out. Note that the resistance torque Te' has a characteristic that increases in proportion to the square of the engine rotational speed, for example. The value of the transmission torque Tr' is calculated by multiplying the read value of the resistance torque Te' by the correction coefficient K, and based on the calculated transmission torque Tr', the transmission torque between the pump impeller 34 and the turbine runner 36 is calculated. Then, find the differential pressure ΔP that produces a predetermined slip amount ΔN that suppresses vehicle body vibration and increases the effectiveness of the engine brake, and find the duty d at which the differential pressure ΔP is obtained. drive signal C having a set duty d.
g is supplied to the pressure regulating solenoid valve 7, and thereafter, as in the case of steady slip control, the detection signal St subtracts the value of the turbine rotation speed to be detected from the value of the engine rotation speed to be detected by the detection signal Sn, and is then re-initiated. In order to bring the value of the rotational speed difference ΔNn closer to the predetermined target slip amount ΔN, a new duty d is set by changing the value of the duty d, and a drive signal Cg having the newly set duty d is formed. By supplying this to the pressure regulating solenoid valve 7, feedback control is performed to make the value of the rotational speed difference ΔNn match the target slip amount ΔN.

Further, if it is detected that the upshift condition is satisfied even though the deceleration slip control condition is satisfied, the control unit 100 performs shift slip control, and also performs shift slip control from 3rd to 2nd speed. If it is detected that the downshift condition from second speed to first speed has been satisfied, the supply of drive signals Cf and Cg to lock-up control solenoid valve 6 and pressure regulating solenoid valve 7 is stopped.

As a result, the lock-up clutch 21 is placed in the released state.

Further, when the control unit 100C detects that the brake pedal is depressed while the deceleration slip control condition is satisfied, the control unit 100c changes the shift from 4th gear to 3rd gear in the shift pattern shown in FIG. The value of the vehicle speed V when the opening degree Th of the throttle valve 14 of the shift line Df that defines the shift down condition is zero is shifted to the high vehicle speed side, and the 4-3 shift down condition is changed, and under this condition, 4th gear is changed. If it is detected that the condition for downshifting from to 3rd gear is met, shift slip control is performed.

As a result, the lock-up clutch 21 is placed in a constant slip engagement state. In this way, lock-up occurs when the downshift conditions from 3rd gear to 2nd gear and from 2nd gear to 1st gear are met, and when the downshift conditions from 4th gear to 3rd gear are met. The reason why the operation state of the clutch 21 is controlled to be different is that the downshift operation from 3rd gear to 2nd gear and from 2nd gear to 1st gear is performed under the condition that the deceleration slip control condition is satisfied. When this occurs, the vehicle speed is assumed to be extremely low, so the engine speed will be lower than the value at which fuel restoration is performed, even though the engine is in a state where fuel restoration is not performed. On the other hand, when a downshift operation is performed from 4th gear to 3rd gear, the engine speed value is higher than the value when fuel restoration is performed, and the engine is in a state where fuel is cut. be.

In this way, during deceleration slip control, the differential pressure ΔP
is set according to the operating state of the engine and the running state of the vehicle, so that a rotational speed difference ΔN suitable for the operating state of the engine can be quickly generated between the pump impeller 34 and the turbine runner 36. Thereby,
Torque fluctuations in the fluid coupling 24 are effectively absorbed, suppressing vehicle body vibration, and improving the effectiveness of engine braking.

Further, when the deceleration slip control condition is satisfied and it is detected that the brake pedal is depressed, the 4-3 downshift condition is changed, thereby shortening the period during which the transmission mechanism 26 is in the 3rd gear. Since the engine speed is longer, the drop in engine speed is suppressed and the period during which the deceleration fuel cut is performed becomes longer.Moreover, when the 4-3 downshift condition is changed, the downshift condition from 4th gear to 3rd gear is satisfied. In this case, shift slip control is performed and the lock-up clutch 21 is brought into the slip-engaged state, thereby increasing the effectiveness of the engine brake compared to when the lock-up clutch 21 is in the released state. At the same time, the drop in engine speed is suppressed, so
The period during which deceleration fuel cut is carried out becomes longer, and as a result,
It is also possible to improve fuel efficiency.

On the other hand, when the deceleration slip control conditions are not satisfied,
When the downshift condition from 4th gear to 3rd gear is satisfied, the lock-up clutch 21 is placed in the released state, which is compared to the case where the lock-up clutch 21 is placed in the slip-engaged state. The engine speed will increase quickly, and the acceleration of the vehicle will be improved.

The control unit 100 that performs the above control is configured using a microcomputer, and an example of a program executed by the microcomputer to control the operation of the lock-up clutch 21 is shown in FIGS. This will be explained with reference to the flowchart in FIG.

In the main program shown in the flowchart of FIG. 12, after starting, various detection signals are acquired in process 101, and in decision 103, it is determined whether or not steady slip control conditions are satisfied, and whether or not steady slip control conditions are satisfied. If it is determined that this is the case, the process proceeds to decision 104, where it is determined whether or not the speed change operation in the speed change mechanism 26 is being performed. If it is determined in decision 104 that a gear shifting operation is not being performed, it is determined in decision 105 whether or not a lock-up activation condition is satisfied, and it is determined that the lock-up activation condition is not satisfied. If so, in process 106, a program for steady slip control shown in FIG. 13, which will be described later, is executed and the process returns to the original state.

Further, if it is determined in decision 104 that a gear shifting operation is being performed, it is determined in decision 107 whether or not the variable operation is a shift-up operation, and if it is determined that it is a shift-up operation In step 109, a shift slip control program shown in FIG. 14, which will be described later, is executed and the process returns.

On the other hand, if it is determined in decision 103 that the steady-state slip control condition is not satisfied, then in decision 110 it is determined whether or not the deceleration slip control condition is satisfied, and it is determined that the deceleration slip control condition is not satisfied. and? 11, the process proceeds to decision 112 where it is determined whether or not a gear shifting operation is being performed. If it is determined that a gear shifting operation is not being performed, the subsequent decision 113 determines whether or not the lockup activation condition has been established. Determine whether it has been established or not. If it is determined in decision 113 that the lock-up operating conditions are not satisfied, in process 115, the supply of the drive signal Cf to the lock-up control solenoid valve 6 is stopped, and the process proceeds to process 116. The supply of the drive signal Cg to the solenoid valve 7 is stopped and the process returns to the original state.

On the other hand, in decision 113, it is determined that the lock-up activation condition is satisfied.7 In this case, in process 117, a drive signal Cf is supplied to the lock-up control solenoid valve 6, and in the subsequent process 118,
The supply of the drive signal Cg to the pressure regulating solenoid valve 7 is stopped and the process returns to the original state. Further, if it is determined in decision 105 that the lockup activation condition is satisfied, processes 117 and 118 are executed in the same manner as described above and the process returns. Furthermore, if it is determined in decision 112 that a gear shifting operation is being performed, the process advances to decision 107, and if it is determined that the gear shifting operation is an upshifting operation, process 109 is executed in the same manner as described above. If it is determined in decision 107 that the shift operation is not an upshift operation, processes 115 and 116 are sequentially executed in the same manner as described above, and the process returns to the original state.

Furthermore, if it is determined in decision 110 that the deceleration slip control condition is satisfied, then in decision 120 it is determined whether or not the brake pedal is depressed, and if it is determined that the brake pedal is depressed; In the process 121, the value of the vehicle speed V when the opening degree Th of the throttle valve 14 of the shift line Df in the shift pattern shown in FIG. In the following decision 122, it is determined whether or not a gear shifting operation is being performed. And decision 12
If it is determined in step 2 that the gear shifting operation is not being performed, in step 124, a deceleration slip control program shown in FIG. 15, which will be described later, is executed and the process returns to the original state.

Further, if it is determined in decision 122 that a gear shifting operation is being performed, it is determined in decision 123 whether or not the gear shifting operation is a 4-3 downshift operation, and it is determined that the gear shifting operation is a 4-3 downshifting operation. If it is determined, process 109 is executed and the process returns. In addition, if it is determined at decision 123 that the shift operation is not a 4-3 downshift operation, then decision 10
7, each step after decision 107 is executed sequentially in the same manner as described above, and the process returns to the beginning. On the other hand, Decision 1
If it is determined in step 20 that the brake pedal is not depressed, the process proceeds to decision 122 without going through process 121, executes each step after decision 122 in sequence as described above, and returns.

In the steady slip control program shown in FIG. 13, after the start with the slip control region determination, in decision 125, it is determined whether the running state is in the hysteresis region shown in the shift pattern of FIG. 4, If it is determined that the vehicle is in the hysteresis region, it is determined at decision 126 whether or not the high speed stage is within this hysteresis region. If it is determined at this decision 126 that the gear is in a low gear, and if it is determined at decision 125 that it is not in the hysteresis region, the process 12
Proceed to step 8 and set the target slip amount ΔN to the normal slip RN.
Set to 1. On the other hand, if it is determined in decision 126 that the gear is in the high speed gear, the target slip amount ΔN is set to the above-mentioned normal slip EI N t and the correction coefficient Cf determined based on the characteristics shown in FIG. 11 according to the vehicle speed V. The process proceeds to decision 129 after setting the value to an incremented value by multiplying by .

In decision 12, it is determined whether or not it is the time to start steady slip control, and if it is determined that it is the time to start steady slip control, in process 130, the engine generated torque Te is detected by a detection signal St. The opening degree Th of the throttle valve 14 and the engine rotational speed Ne at which the detection signal Sn is detected are compared with the map shown in FIG. 9, and the corresponding engine generated torque Te is read out and set, and in the subsequent process 131, A correction coefficient K is set based on the temperature of the working surface at which the detection signal Su occurs, and in process 132, the transmission torque T is calculated using the formula: Tr-Te.
Set by XK and proceed to process 133.

In process 133, the differential pressure ΔP for obtaining the target slip amount ΔN is set based on the transmission torque Tr, and the process proceeds to process 134. At 135, duty d is set to the value yn and processing continues at process 136. In process 136, a drive signal Cf is supplied to the lock-up control solenoid valve 6, and in the following process 137, a drive signal Cg having the duty d set in process 135 is formed and supplied to the pressure regulating solenoid valve 7. and exit this program.

On the other hand, if it is determined after the start of control that it is determined in decision 12 that it is not the time to start control, the process proceeds to process 138, where the actual slip amount is calculated by subtracting the turbine speed from the engine speed at that time, and the target slip amount is calculated. The deviation ΔNn from ΔN is calculated, and in process 139, the formula: Z
-AXΔNn+B×ΔN n-1 calculates the corrected calculation value Z, and in process 140, sets the addition value ΔX according to the corrected calculation value Z. In the subsequent process 141, the value yn of duty d is calculated using the formula -:yn''"Y. -00ΔX
Processes 135 to 137 are sequentially executed in the same manner as described above, and this program is terminated.

In the shift slip control program shown in FIG. 14, after the start, it is determined in decision 142 whether or not it is the time to start shift control, and if it is determined that it is the time to start shift control, in decision 143, It is determined whether or not the lock-up clutch 21 is in the slip engagement state. If it is determined that the lock-up clutch 21 is in the slip engagement state, the process proceeds to process 144, where the duty d is set to the previously set value. y. -1, and in process 145, a drive signal Cf is supplied to the lock-up control solenoid valve 6, and the process proceeds to process 146. In process 146, a drive signal Cg having the duty d set in process 144 is formed;
This is supplied to the pressure regulating solenoid valve 7, and this program ends.

In addition, if it is determined in decision 142 that it is not the time to start the shift control, processes 145 and 1
46 to terminate this program.

On the other hand, if it is determined in decision 143 that the lock-up clutch 21 is not in the slip-engaged state, processes 147 to 150 are executed in the same manner as processes 129 to 133 of the program shown in FIG. , proceed to process 151. In process 151, a value yn that causes differential pressure ΔP is determined, and in process 15
2, set the duty d to the value yn, and process 1
At 53, a drive signal Cf is supplied to the lock-up control solenoid valve 6, and at the subsequent process 154,
The drive signal Cg having the duty d set in process 152 is supplied to the pressure regulating solenoid valve 7, and this program ends. In the shift slip control program described above, the value of the differential pressure ΔP is obtained in the same manner as in the steady slip control program shown in FIG. is assumed to be less than the value.

In the deceleration sleeve control program shown in the flowchart of FIG.
In step 59, it is determined whether or not it is the time to start deceleration slip control, and if it is determined that it is the time to start deceleration slip control, the resistance torque Te' is set in process 160, and the correction coefficient K is set in process 161. Then, in the subsequent process 162, the transmission torque Tr' is set by multiplying the resistance torque Te' by the correction coefficient K. In the subsequent process 163, the transmission torque Tr'
In process 164, a value yn that causes the differential pressure ΔP is set. In process 165, duty d is set to value yn, and in process 166.
In step 167, the drive signal Cf is supplied to the lock-up control solenoid valve 6, and the process proceeds to process 167. Process 16
At step 7, the drive signal Cg having the duty d set at step 165 is supplied to the pressure regulating solenoid valve 7, and this program ends. Also, decision 1
If it is determined in step 59 that it is not the time to start deceleration slip control, processes 168 to 171 are replaced with processes 138 to 138 in steady slip control shown in FIG.
Execute in the same manner as in step 141 and proceed to process 165,
Processes 165 to 167 are executed sequentially in the same manner as described above, and the program is terminated.

(Effects of the Invention) According to the present invention as described above, when performing slip control by controlling the engagement force of the lock-up clutch of a fluid coupling, the engagement force of the lock-up clutch within the hysteresis region of the slip control region is shifted. By providing a fastening force correction means that corrects according to the gear, it is possible to obtain good driving performance when accelerating in a high gear in the hysteresis region, while ensuring fuel efficiency in a low gear, and making it possible to maintain good driving performance when accelerating in a high gear in the hysteresis region. Good slip control can be obtained even in the stages.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram to clarify the configuration of the present invention, Fig. 2 is a schematic configuration diagram showing a slip control device for a fluid coupling in one embodiment together with a power plant of a vehicle, and Fig. 3 is the same as Fig. 2. A schematic configuration diagram showing the main parts of the example shown, FIGS. 4 to 11 are characteristic diagrams showing various control characteristics in slip control, and FIGS. 12 to 15 are flowcharts for explaining the processing of the control unit. It is. A, 24...Fluid coupling, B, 21...
Lock-up clutch, C...Fascinating force control means, D...Fascinating force correction means, E...Area determination means, 6...Solenoid for lock-up control Valve, 7... Solenoid valve for pressure regulation, 10...
... Engine body, 14 ... Throttle valve,
20... Automatic transmission, 30... Hydraulic circuit section, 34... Pump impeller, 36...
... Turbine runner, 43 ... Release chamber, 4
4... Closing chamber, 51... Lock-up shift valve, 52... Lock-up pressure regulating valve, 81
...Throttle opening sensor, 82...
Vehicle speed sensor, 100... Control unit. Figure 8 Figure 14 Figure 5

Claims (1)

[Claims] (1) The lock-up clutch is capable of controlling the lock-up force, and includes a lock-up force control means that performs slip control to control the lock-up clutch to a predetermined slip state when the operating state is in a predetermined slip control range, and the slip control means In a slip control device for a fluid coupling in which a plurality of gears are set within a hysteresis region of a shift line in a region, a region determining means for determining the hysteresis region is provided, and a region determining means receives a signal from the region determining means to determine the hysteresis region. 1. A slip control device for a fluid coupling, comprising a fastening force correcting means for correcting a fastening force of a lock-up clutch therein according to a gear position.