JP2687001B2 - Fluid coupling slip control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fluid coupling provided with a lock-up clutch, and more particularly to a fluid coupling slip control device for controlling a slip state of the lock-up clutch.

(Prior Art) Generally, in a fluid coupling (torque converter) provided with a lock-up clutch, the lock-up clutch is released at a low vehicle speed at which the torque fluctuation of the engine is transmitted to the wheels and the ride comfort of the vehicle is reduced. While the converter operates in a converter state having a torque increasing function and a torque fluctuation absorbing function, at a high vehicle speed at which engine torque fluctuation is not so problematic, the lock-up clutch is engaged to directly connect the input and output shafts, and the fluid coupling The operation is performed in a lock-up state in which the energy loss due to the slip is reduced to improve the fuel efficiency.

Further, in the fluid coupling including the lock-up clutch as described above, in a low vehicle speed and low load state region, it is preferable to set the lock-up state rather than the converter state from the viewpoint of improving fuel efficiency. Then, the torque fluctuation of the engine is directly transmitted to the wheels, and vibrations occur in the vehicle body.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-52427, the lockup clutch is improved in order to improve the fuel efficiency to some extent and reduce the transmission of torque fluctuation to suppress gear shift shock and vehicle body vibration. There is known a slip control device that controls a slip state between a lockup state and a converter state to cause a predetermined rotation difference between input and output.

The control by the slip control device adjusts a differential pressure between the pressure of the engagement chamber acting on the lock-up clutch in the engagement direction and the pressure of the release chamber acting on the release direction, and the lock-up clutch is brought into a predetermined slip state. Thus, a mechanism for controlling the differential pressure is employed. The differential pressure control sets the input-side rotational speed and the output-side rotational speed of the lock-up clutch as a predetermined rotational difference, thereby achieving both fuel economy and traveling performance.

As specific slip control, feedback control for adjusting the operating oil pressure supplied to the lock-up clutch based on the input / output rotation difference, or control for maintaining the operating pressure supplied to the lock-up clutch at a set value is performed. ing.

(Problems to be Solved by the Invention) However, in the case where the slip control of the lock-up clutch is performed by the feedback control of the rotation difference, depending on the magnitude of the input torque transmitted to the fluid coupling and its fluctuation, If the response delay time until the rotation difference between input and output reaches the target value increases and an appropriate slip state cannot be obtained, or if the control gain in feedback control is set large to increase the response speed,
A hunting phenomenon may occur due to lack of control stability or a problem may occur in control accuracy.

Further, in the control for maintaining the operating pressure for the lock-up clutch at a set value, when the magnitude of the input torque at the time of starting the slip control varies according to the operating state of the engine, the running state of the vehicle, or the like, an appropriate slip is performed. There is a possibility that the state cannot cope with the change.

In particular, in order to perform slip control of the lockup clutch so that a predetermined rotation difference occurs between input and output, it is necessary to change the operating pressure to be supplied to the lockup clutch in response to changes in input torque, that is, engine output. However, when controlling the drive signal when the required differential pressure changes with its duty value, if the drive signal is set as it is in response to changes in the operating state, the response and stability of the differential pressure control May cause problems in terms of

Further, in order to improve the control response in the slip control performed by the feedback control as described above, the target rotation difference is obtained for the fluctuation of the operating state and the differential pressure is set,
The drive signal is output so that this differential pressure is obtained,
If feed-forward control is performed in response to changes in the operating state without using feedback control, responsiveness may be improved, but control stability near the target value may not be secured sufficiently.

Therefore, in view of the above circumstances, the present invention provides a slip control device for a fluid coupling, which performs slip control of a lockup clutch by appropriate differential pressure control corresponding to a required rotation difference even during a transition in which the operating state changes. The purpose is to do.

(Means for Solving the Problems) In order to achieve the above object, a slip control device for a fluid coupling according to the present invention, as shown in FIG. 1, shows a basic configuration thereof through a fluid between an input element and an output element. The fluid coupling A having a converter function for transmitting torque includes a lock-up clutch B to which an input element and an output element can be directly connected.

The engagement force of the lock-up clutch B is controlled by a slip control device C that 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 with the duty value of the drive signal. It

The slip control device C includes a target rotation difference setting means D for setting a target rotation difference of the input / output rotation difference and an input / output rotation difference detection means E for detecting a current input / output rotation difference. The signal of the means D is output to the differential pressure setting means F. The differential pressure setting means F is for obtaining the target differential pressure of the lockup clutch B corresponding to the target rotational difference.

Further, the drive signal determination means G which receives the signals from the differential pressure setting means F and the input / output rotation difference detection means E determines the duty value of the drive signal corresponding to the set differential pressure as the current input / output rotation difference and the target rotation speed. The determination is made based on the deviation from the difference and the change state of the duty value.

Further, the drive signal determining means G determines the final duty value by reflecting the change state of the duty value with a larger ratio as the deviation between the input / output rotation difference and the target rotation difference increases positively and negatively. Is desirable. The drive signal determining means G also increases the final change in duty value when the change in the duty value with respect to the set differential pressure is large, and the final change in duty value is small when the change in the drive signal with respect to the set differential pressure is small. It is preferable to determine.

(Operation) In the slip control device for a fluid coupling as described above, in controlling the slip state by controlling the differential pressure between the engagement chamber and the release chamber of the lockup clutch, the differential pressure is set corresponding to the target rotation difference. At the same time, the deviation between the current input / output rotation difference and the target rotation difference is obtained, and the duty value corresponding to the differential pressure is obtained based on this deviation, and at the same time, the drive signal actually output based on the change state of the duty value is calculated. The duty value is determined, and the differential pressure control corresponding to the rotation difference is accurately performed in consideration of responsiveness and stability.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Second
The figure shows an example of a slip control device for a fluid coupling together with a power plant of a vehicle to which the slip control device is applied.

The power plant includes an engine body 10 and an automatic transmission 20. In each cylinder of the engine body 10 (four cylinders), intake air from an intake passage 16 provided with a throttle valve 14 and injection from a fuel injection valve are provided. The fuel-air mixture is supplied and compressed and combusted, and the generated torque is transmitted to the wheels via a power transmission path including the automatic transmission 20.

In the engine body 10, the fuel supply is stopped when the engine speed is equal to or higher than the predetermined value and the throttle is fully closed, and the fuel supply is restarted when the engine speed becomes lower than the predetermined value from this fuel cut state. Deceleration fuel control is performed.

The automatic transmission 20 includes a fluid coupling 24 (torque converter), a multi-stage gear type transmission mechanism 26, shift control solenoid valves 1 to 5 for forming the operating oil pressure used for controlling them, lock-up control. And a hydraulic circuit unit 30 provided with a solenoid valve 6 for pressure control and a solenoid valve 7 for pressure regulation.

As shown in FIG. 3 along with a portion related to the operation control of the fluid coupling 24 in the hydraulic circuit unit 30, the fluid coupling 24 is provided between the input shaft 25 to which the output of the engine body 10 is input and the output shaft 39. And a converter unit 27 that transmits torque through a fluid.
And a lock-up clutch 21 that transmits torque in a directly connected state or a slip state. The converter unit 27 is a drive plate that rotates integrally with the input shaft 25.
Pump impeller 34 as input element fixed to 32
A turbine runner 36 that rotates integrally with the output shaft 39,
The lock-up clutch 21 includes a torsion damper 23 spline-fitted to an output shaft 39 and a clutch plate 22 connected to the torsion damper 23 via a coil spring 23a. ing.

Due to the arrangement of the lock-up clutch 21, a release chamber 43 is formed between the clutch plate 22 and the drive plate 32 on the back side, and a fastening chamber 44 is formed on the opposite side. The release chamber 43 is supplied with hydraulic pressure for releasing the clutch plate 22 from the hydraulic circuit section 30 through the oil passage 42, and the engagement chamber 44 is supplied with hydraulic pressure for engaging and operating the clutch plate 22 through the oil passage 41. . The lock-up clutch 21 is in a lock-up state where hydraulic pressure is fed to the engagement chamber 44 to directly connect the pump impeller 34 and the turbine runner 36, and hydraulic pressure is fed to the release chamber 43 to pump the impeller 34 and the turbine. When the runner 36 is disengaged (converter state) and the hydraulic pressure is supplied to both the fastening chamber 44 and the release chamber 43, the differential pressure ΔP is within a predetermined range. The slip state that allows the relative rotation between the pump impeller 34 and the turbine runner 36,
The larger the differential pressure ΔP is, the smaller the slip amount is and the closer to the lockup state. The fastening chamber 44 is provided with a check valve 46.
Are connected to an oil cooler 48 through an oil passage 47 provided with a.

A lock-up shift valve 51, a lock-up pressure regulating valve 52, the lock-up control solenoid valve 6, and a pressure regulating solenoid valve 7 are provided in a portion of the hydraulic circuit unit 30 involved in the operation control of the fluid coupling 24. The lock-up shift valve 51 switches the open / close and drain of the ports b, c, and e-g by operating the divided first spool 56 and the second spool 57 in accordance with the hydraulic pressure adjustment to the ports a, d, and h. It is. Further, the lock-up pressure regulating valve 52 is connected to the ports i, n
Port j by the operation of the spool 60 with the hydraulic pressure adjustment to
Ｍm to switch between open / close and drain.

In the lock-up shift valve 51, the port
a, d, and h are oil pumps 45 regulated by the pressure regulating solenoid valve 7 or the lock-up control solenoid valve 6.
Is supplied, and the supply of the hydraulic pressure of the fluid coupling 24 is switched to operate in a converter state, a lockup state, and a slip state. In the lock-up pressure regulating valve 52, the port i is supplied with the throttle pressure Pt regulated by the throttle pressure forming section 61 in accordance with the throttle opening, while the port n is regulated by the pressure regulating solenoid valve 7. The regulated duty control pressure Pd is supplied, and the slip amount is controlled by adjusting the pressure difference ΔP between the fastening chamber 44 and the release chamber 43 of the fluid coupling 24.

The description of the state change of the fluid coupling 24 due to the operation of the lock-up shift valve 51 and the lock-up pressure regulating valve 52 is omitted here, but the details are described in the specification of Japanese Patent Application No. 63-278607 by the same applicant. See description.

As shown in FIG. 2, in order to control the operation of the hydraulic circuit unit 30, the shift control solenoid valves 1 to 5, the lock-up control solenoid valve 6, and the pressure regulating solenoid built in the hydraulic circuit unit 30 are provided. The valve 7 is provided with a control unit 100 that outputs drive signals Ca to Cg, respectively. The control unit 100 includes a detection signal St obtained from a throttle opening sensor 81 that detects the opening Th of the throttle valve 14, a detection signal Sv obtained from a vehicle speed sensor 82 that detects a vehicle speed V, and operation of a shift lever. Detection signal obtained from shift position sensor 83 that detects the position
Ss, a detection signal Sn obtained from an engine speed sensor 84 that detects the engine speed Ne (input speed), and a detection signal Sn obtained from a turbine speed sensor 85 that detects the speed (output speed) of the turbine runner 36. A detection signal Sm, a detection signal Sa obtained from an accelerator sensor 86 that detects the amount of depression of an accelerator pedal, and a detection signal Su obtained from an oil temperature sensor 87 that detects the temperature of hydraulic oil supplied to the automatic transmission 20. ,
A detection signal Sb obtained from a brake sensor 88 for detecting the amount of depression of the brake pedal is supplied, and other detection signals Sx necessary for controlling the automatic transmission 20 are also supplied.

The control unit 100 performs shift control in the automatic transmission 20 and operation control of the lock-up clutch 21 with desired characteristics based on the various detection signals.

In performing the shift control of the automatic transmission 20 and the operation control of the lock-up clutch 21 by the control unit 100, a shift pattern as shown in FIG. , The control area is determined. In this shift pattern, the vertical axis indicates the throttle opening Th, and the horizontal axis indicates the vehicle speed V. The areas of each shift speed during upshifting are indicated by upshift lines Ua, Ub, Uc, and the areas are The time of the change corresponds to the time of the shift-up shift, while the area of each shift speed at the time of the shift-down corresponds to the shift-down shift lines Dd, De,
When the area is changed and indicated by Df, a downshift is performed. The lock-up operation lines Lg (fourth speed), Li (3
Inside the (speed) is the lock-up area when shifting to the lock-up state. Release from the lock-up state is indicated by lock-up release lines Lh (4th speed) and Lj (3rd speed), and lock-up is performed when the area changes. It is at the time of operation and release control to the state. Furthermore, the inside of the slip control execution line Rj set in the region of the low throttle opening on the relatively low vehicle speed side is the slip control region, and the slip control is started when shifting to this region, and the slip control is set outside this region. The control is performed such that the slip control is released when the vehicle shifts to a region outside the slip control release line Rk.

Then, the control unit 100 controls the shift line Ua
UUc, Dd〜Df, when it is detected that the upshift condition or the downshift condition is satisfied, the drive signals Ca〜
Ce is selectively transmitted to perform shift control. When neither the lockup operation condition nor the slip control condition described later is satisfied, the drive signals Cf and Cg to the lockup control solenoid valve 6 and the pressure adjustment solenoid valve 7 are provided.
Stop supplying. As a result, the two solenoid valves 6 and 7 are closed, the lock-up shift valve 51 and the lock-up pressure regulating valve 52 are at the positions indicated by the solid lines in FIG. 3, and the hydraulic pressure regulated by the regulator valve 49 is directly applied to the release chamber 43. At the same time, the oil pressure in the fastening chamber 44 is discharged to the oil cooler 48, the lock-up clutch 21 is released, and the torque is transmitted by the converter 27.

Further, when the lock-up operation condition is satisfied, the drive signal Cf is supplied to the lock-up control solenoid valve 6 to be opened, 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 in the position indicated by the dashed line, the lock-up pressure regulating valve 52 is in the position indicated by the solid line, and the hydraulic pressure regulated by the regulator valve 49 is supplied to the fastening chamber 44, while the hydraulic pressure in the release chamber 43 is After being discharged to the pan, the lock-up clutch 21 is in the engaged state, and is in the lock-up state in which input and output are directly connected.

On the other hand, when the throttle opening Th and the vehicle speed V are in the slip control region and the steady-state slip control condition is satisfied, when the shift-up condition is satisfied and the shift slip control condition is satisfied, and when the throttle opening is fully closed and the engine is closed. When the deceleration slip control condition is satisfied at the time of deceleration at or above the predetermined value, the drive signal Cf is supplied to the lock-up control solenoid valve 6 to be opened, and the pressure adjustment solenoid valve 7 is set to 20%. Drive signal Cg having the above duty value d
Is operated to a predetermined opening degree by the supply of. As a result, in the lock-up shift valve 51, the first spool 56 is positioned at the solid line,
The second spool 57 is at the position indicated by the chain line, and the lock-up pressure regulating valve 52 is a solid line for a distance corresponding to the differential pressure between the throttle pressure Pt of the port i and the duty control pressure Pd of the port n (the lower the greater the duty value). From the position indicated by the dashed line, the hydraulic pressure regulated by the regulator valve 49 is supplied to the fastening chamber 44, and the hydraulic pressure reduced according to the duty value is supplied to the release chamber 43. Is a slip state in which an input / output rotation difference ΔN corresponding to the pressure difference ΔP obtained by subtracting the oil pressure of the release chamber 43 from the oil pressure of the fastening chamber 44 is generated between the input shaft 25 and the output shaft 39.

In this case, the differential pressure ΔP is obtained from the throttle pressure Pt, the duty control pressure Pd, and the urging force Fa of the spring 62.
If C ₁ and C ₂ are constants, ΔP = C ₁ (Pt−Pd) + Fa / C ₂ , and the differential pressure ΔP is defined by the throttle pressure Pt and the duty control pressure Pd. And the throttle pressure Pt
Is formed so as to have the characteristics shown in FIG. 5, for example, with respect to the throttle opening Th, and the duty control pressure Pd is formed, for example, as shown in FIG. 6, with respect to the duty value d of the drive signal Cg. It is formed so as to have the characteristics described below. As a result, the differential pressure ΔP increases as the throttle opening Th and the duty value d increase as shown in FIG. 7 in which the duty values d of 20%, 50%, and 80% are used as parameters. .

The transmittable torque Ts as the maximum torque that can be transmitted from the input shaft 25 to the output shaft 39 in the engaged state by the lock-up clutch 21 depends on 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 by Ts = ΔP · μ · r · A, and the value becomes larger as the differential pressure ΔP increases. The input torque Ti of the fluid coupling 24 is equal to the engine generated torque Te transmitted to the input shaft 25,
If the torque is larger than the transmittable torque Ts, the input / output rotation difference ΔN occurs. The relationship between the input torque Ti and the input / output rotation difference ΔN is as follows:
Using the differential pressure ΔP set at ¹ to 4 kg / cm ² as a parameter, the characteristics as shown in FIG. 8 are obtained.

From the above, when the slip control of the lock-up clutch 21 in the fluid coupling 24 is performed, first, it is detected that the steady-state slip control condition is satisfied without the shift slip control condition being satisfied. In this case, the value of the engine generated torque Te is detected based on the throttle opening Th and the engine speed Ne. The value of the engine generated torque Te is determined in advance by the throttle opening.
Th is obtained from a map set in accordance with Th and the engine speed Ne. For example, as shown in FIG. 9, the horizontal axis represents the engine speed Ne, and the throttle opening Th (1/8 to 6/8) )
Shown by the curve a ₁ ~a ₆ as parameters.

The transmission torque Tr is obtained by performing oil temperature correction on the value of the engine generated torque Te detected in this manner, and the correction coefficient K1 is ₁ at a temperature of the operating oil of 90 ° C. and _{1 as} the operating oil temperature becomes higher than 90 ° C.
To a larger value is set to a value smaller than 1 as below 90 ° C., obtaining the transmitted torque Tr is multiplied by the correction coefficient K ₁ to the engine generated torque Te.

Further, the transmission torque Tr is corrected by the amount of change in the throttle opening Th. This correction is performed to detect the engine output torque Te as described above from the map of the engine speed Ne and the throttle opening Th. When the amount of change, that is, the changing speed is large, the actual increase of the engine output is delayed and the deviation from the map value is corrected so that the value of the transmission torque Tr becomes smaller as the amount of change in the throttle opening becomes larger. This correction calculates the change amount ΔTh of the throttle opening Th from the difference from the previous throttle opening,
When the change amount ΔTh is a positive value and the vehicle is accelerating, the map shown in FIG.
The calculated correction factor K ₂ which is set to a small value below, is corrected by multiplying the correction coefficient K ₂ to the transmitted torque Tr. In addition,
When the throttle opening change amount ΔTh increases, it deviates from the steady slip control region of FIG.

And, corresponding to the value of the transmission torque Tr, the fluid coupling
Between the input shaft 25 and the output shaft 39 in 24, a predetermined target rotation difference No, for example, 80 to which energy loss is reduced and torque fluctuation generated by the engine is both absorbed.
The value of the differential pressure ΔP is set by reading the relationship between the input torque Ti, the input / output rotation difference ΔN, and the differential pressure ΔP in FIG. 8 so as to generate 150 rpm. The rotation difference No is set to an optimum value in view of the control responsiveness and the convergence according to the current input / output rotation difference ΔN.

The target rotation difference No is set by subtracting the output rotation speed from the input rotation speed (engine rotation speed Ne) to obtain the input / output rotation difference ΔN, reading the target rotation difference No (initial value), and calculating the deviation ΔN− The correction value α or β is retrieved from the map of FIG. 11 or FIG. 12 based on the value of No, and is corrected by adding or subtracting the target rotation difference No. The correction value α is a correction value when the input / output rotation difference ΔN is larger than the target rotation difference No by a predetermined value or more. The direction in which the target rotation difference No is corrected low to increase the differential pressure ΔP and reduce the input / output rotation difference ΔN. The responsiveness is improved. In addition, the correction value β is obtained when the input / output rotation difference ΔN
With a correction value smaller than a predetermined value, the target rotation difference No is corrected to be high to reduce the differential pressure ΔP, and the responsiveness is improved in a direction to increase the input / output rotation difference ΔN. This converges to the target rotation difference No.

From the relationship between the target rotation difference No and the transmission torque Tr, the differential pressure ΔP
Further, a duty value Dk corresponding to the characteristic shown in FIG. 7 is obtained from the differential pressure ΔP and the throttle opening Th, and the finally output duty value d secures the stability of the control system. Therefore, the amount of change in the read duty value Dk is reflected by the value of the difference ΔN−No between the input / output rotation difference ΔN and the target rotation difference No. That is,
In determining the duty value d, the values of the correction coefficients F ₁ and F ₂ are searched from the map as shown in FIG. 13 based on the deviation ΔN−No.
Further, based on the duty value Dk obtained this time, the previous value Dk-1, and the last-before-time value Dk-2, an updated value ΔD is obtained by a calculation formula described in detail in a flowchart described later, and the updated value ΔD is added to the previous value Dk-1 to obtain the final value. A typical duty value d is determined.

Then, the control unit 100 performs a steady slip control in which a drive signal Cg having a duty value d corresponding to the set differential pressure ΔP is formed and supplied to the pressure regulating solenoid valve 7.

The processing of the control unit 100 will be described with reference to the flowcharts of FIGS. FIG. 14 shows a main routine of the slip control.
In step S1, the type of slip control is determined, and whether the slip is the steady slip S2, the deceleration slip S3, or the shift slip S4 is determined according to a slip state determined in a control region determination routine of FIG.

First, in the case of the steady slip control S2, the engine output torque Te is obtained in step S5 based on the detected engine speed Ne and the throttle opening Th based on the characteristics shown in FIG. Then, corrected by the correction factor K ₁ in accordance with the engine output torque Te of the oil temperature at step S6,
The transmission torque Tr (input torque Ti) is obtained.

Next, in step S7, the transfer torque Tr is corrected based on the change amount ΔTh of the throttle opening Th, that is, the changing speed based on the characteristic of FIG. 10, and the actual engine output is changed with respect to the change of the throttle opening during acceleration. Suppress the shift due to rising delay.

Subsequently, a differential pressure ΔP is determined in step S8,
The detailed steps are shown in FIG. First, step S20
Is calculated by subtracting the turbine speed Nt (output speed) from the engine speed Ne (input speed). In step S21, the initial value of the target speed difference No (for example, 1
50rpm). Then, in step S22, the difference ΔN-No is calculated, and in step S23, it is determined whether the difference ΔN-No is positive. By the time this determination is YES, if input and output rotation difference ΔN predetermined value E ₁ or greater than the target rotational difference No is determined in step S24, the deviation ΔN at step S25
Based on the value of -No, a correction value α is retrieved from the map of FIG. 11, and in step S26, the correction value α is subtracted from the target rotation difference No to correct it to a small value. On the other hand, when the determination of the step S23 is NO, when input rotation difference ΔN is the predetermined value E ₂ or more smaller than the target rotational difference No is determined in step S27,
In step S28, the twelfth is calculated based on the absolute value of the deviation ΔN-No.
A correction value β is retrieved from the map shown in the figure, and in step S29, the correction value β is added to the target rotation difference No to correct the correction value to a large value. In addition, if the determination in step S24 or S27 is NO and after the target rotation difference No is corrected as described above, it is determined from the relationship between the target rotation difference No and the transmission torque Tr in step S30 that the eighth
The value of the differential pressure ΔP is obtained from the map shown in FIG.

Then, the process proceeds to step S9, in which a duty value Dk corresponding to the differential pressure ΔP and the throttle opening Th is obtained based on FIG. 7, and a duty value d to be finally output is calculated in step S10. d is output to the solenoid valve 7 in step S19 to drive it.

The details of the duty calculation in step S10 are as follows. As shown in FIG. 17, in step S40, the values of the correction coefficients F ₁ and F ₂ are retrieved from the map as shown in FIG. . The correction coefficients F ₁ and F ₂ are set to larger values as the difference ΔN−No increases in the positive and negative directions. Then, in step S41, the duty value Dk obtained this time is read, and the update value ΔD is obtained by calculation in step S42, and is added to the previous value Dk-1 to determine the final duty value d (S43). Calculation of the step S42 is the difference between the value obtained by multiplying the correction factor F ₁ of the current duty value Dk and previous value Dk-1, the correction factor F to the difference between the previous value Dk-1 and the second preceding value Dk-2 _When the state change is large, the duty value change is increased, and when the state change is small, the fluctuation of the duty value d is reduced and stabilized. I have.

Next, in the case of the deceleration slip control S3, the minimum transmission torque at the time of deceleration is searched from the map in step S12. At the time of this deceleration, the engine is in a state where torque is transmitted from the wheels. Therefore, the minimum transmitted torque transmitted from the wheels to the engine, which is obtained in advance by experiments or the like and stored in the internal memory according to the engine speed, is calculated. read out. And
Proceeding to step S6, the differential pressure ΔP is determined so as to attain a predetermined target rotation difference No corresponding to the transmission torque, the duty value d is set, and the deceleration slip control is performed.

On the other hand, in the case of the slip control during shifting S4, step S13
It is determined whether or not the shift control at the time of shifting is to be started, and at the start, it is determined in step S14 whether the immediately preceding state is the slip control state, the other converter state, or the lockup state. If the immediately preceding state is the slip control state, the value of the duty value d is set to the value immediately before the currently set shift in step S15, and this value is set as the duty value d during shifting in step S18, and the solenoid The valve 7 is driven (S19). If the immediately preceding state is the converter or lock-up state, the engine output torque Ti is detected from the engine speed Ne and the throttle opening Th in the same manner as when the steady slip control condition is satisfied in step S16,
In step S17, a pressure difference ΔP for generating a predetermined target rotation difference No is set by a transmission torque Tr based on the pressure difference, a duty value d for obtaining the pressure difference ΔP is determined, and the duty value d during the gear shift is used as a pressure adjustment solenoid. Operate the valve 7 (S18,
S19) This shift slip control is performed until the shift operation is completed.

FIG. 15 is a control region determination routine. In step S50, it is determined from the detected values of the throttle opening Th and the vehicle speed V based on the shift pattern in FIG. 4 whether or not the vehicle is in the steady slip control region. If it is within the steady slip control region, after returning the 4-3 speed shift down shift line in which the throttle opening of the shift pattern is 0 in step S51 to the normal state in step S51, it is determined in step S52 whether the shift is in progress. judge.
When the gear is not being changed, the steady slip control S61 is performed, while when the gear is being changed, the shift slip control S64 is performed when the shift is up in the determination of step S53, and the converter control S63 (lockup release) is performed when the shift is down. I do.

In addition, if it is out of the steady slip control region, the step
If the deceleration slip condition is satisfied in the determination of S54, the operation state of the brake is determined by the ON state of the brake switch in step S55. Then, at the time of the brake operation, in step S56, the 4-3rd shift down shift line of the shift pattern is changed to enhance the sense of deceleration due to the engine brake. When the deceleration slip condition is satisfied, step S5
The shift slip control (S
While performing 64), if the shift is not in progress, deceleration slip control (S65) is performed.

Further, when the deceleration slip condition is not satisfied outside the steady slip region, the 4-3 speed downshift line of the shift pattern is returned to the normal state in step S58, and it is determined in step S59 whether the gear is being shifted. judge. And
If the shift is not in progress, lock-up control (S62) is performed when the vehicle is in the complete lock-up region as determined in step S60, and converter control (S63) is performed when the vehicle is not in the lock-up region. Further, when the shift is being performed according to the determination in step S59, the shift slip control S64 is performed when the upshift is performed in the determination in step S53, and the converter control S63 is performed when the downshift is performed.

When performing the steady, shift, and deceleration slip control based on the determination of the control mode as described above, the slip control based on FIG. 14 is performed. Note that the converter control and the lock-up control are performed according to a known control mode, and the details are omitted.

When the control unit 100 detects that the shift down condition is satisfied, the control unit 100 stops supplying the drive signals Cf and Cg to both solenoid valves 6 and 7, except when the engine is in a decelerating state. The lock-up clutch 21 is operated in a released state. When it is detected that the upshift condition is satisfied while the deceleration slip control condition is satisfied, the shift slip control is performed, and further, the downshift condition to the 3-2nd speed and the 2-1st speed is satisfied. Is detected, both solenoid valves 6, 7
Is stopped, and the lock-up clutch 21 is released.

According to the above-described embodiment, at the time of the steady slip control, the input / output rotation difference ΔN is determined according to the input torque Ti of the fluid coupling 24 in which the differential pressure ΔP is corrected by the amount of change in the throttle opening.
Optimum target rotation difference No is set according to and the control responsiveness is determined to be higher, and the final duty value d is calculated and set so as to stabilize the control. In addition, it is possible to stably generate the input / output rotation difference ΔN with good responsiveness, which can reduce both the energy loss in the fluid coupling 24 and absorb the torque fluctuation generated by the engine. Thereby, the fuel efficiency of the vehicle can be improved, and the vibration of the vehicle body can be suppressed.

Further, also in the shift slip control, the differential pressure ΔP is set according to the transmission torque Tr, so that the slip control suitable for the driving state can be performed. Further, also in the deceleration slip control, the input / output rotation difference is controlled according to the transmission torque Tr,
A good feeling of deceleration can be obtained in relation to suppression of vehicle body vibration and deceleration fuel cut.

In the above embodiment, the steady slip control is performed when it is detected that it is in the slip control region in the shift pattern of FIG. 4 set by the throttle opening and the vehicle speed. It may be performed when it is detected that one of the throttle opening and the vehicle speed is in a specific region in the shift pattern.

(Effects of the Invention) According to the present invention as described above, in controlling the slip state by controlling the differential pressure between the engagement chamber and the release chamber of the lockup clutch, the differential pressure is set in correspondence with the target rotation difference. , The deviation between the current input / output rotation difference and the target rotation difference is obtained, and the duty value corresponding to the differential pressure is obtained based on this deviation, and at the same time, the duty of the drive signal actually output based on the change state of the duty value. By determining the value, it is possible to accurately control the differential pressure corresponding to the rotation difference in consideration of responsiveness and stability.

[Brief description of the drawings]

FIG. 1 is a functional block diagram for clearly showing 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. FIGS. 4 to 13 are characteristic diagrams showing various control characteristics in slip control, and FIGS. 14 to 17 are flow chart diagrams for explaining the processing of the control unit. It is. A, 24 …… Fluid coupling, B, 21 …… Lock-up clutch, C
... Slip control device, D ... Input torque detecting means, E
...... Input / output rotation speed detection means, F ...... differential pressure setting means, G ...
... Drive signal determining means, 6 ... Lockup control solenoid valve, 7 ... Pressure adjusting solenoid valve, 10 ... Engine body, 14 ... Throttle valve, 20 ... Automatic transmission, 30 ... Hydraulic circuit section, 34 …… Pump impeller, 36 …… Turbine runner, 43 …… Release chamber, 44 …… Fastening chamber, 51 …… Lockup shift valve, 52 …… Lockup pressure regulating valve, 81 …… Throttle opening sensor, 82… … Vehicle speed sensor, 100… Control unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Takemoto 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) Reference JP-A-61-52427 (JP, A)

Claims (3)

(57) [Claims] Claim: What is claimed is: 1. A fluid coupling in which a differential pressure between an engagement chamber and a release chamber of a lockup clutch is controlled by a duty value of a drive signal, and an engagement force of the lockup clutch is adjusted to control an input / output rotation difference. In the slip control device, the target rotation difference setting means for setting the target input / output rotation difference, the input / output rotation difference detection means for detecting the current input / output rotation difference, and the target rotation difference setting means are set. A differential pressure setting means for setting the differential pressure corresponding to the target rotational difference, and a signal from the differential pressure setting means and the input / output rotational difference detecting means,
Drive signal determining means for determining the duty value of the drive signal corresponding to the set differential pressure based on the deviation between the current input / output rotation difference and the target rotation difference and the change state of the duty value. Slip control device for fluid coupling. 2. The drive signal determining means determines the final duty value by reflecting the change state of the duty value with a larger ratio as the deviation between the input / output rotation difference and the target rotation difference increases positively and negatively. The slip control device for a fluid coupling according to claim 1, wherein: 3. The drive signal determining means increases the final duty value change when the change of the duty value with respect to the set differential pressure is large, and the final duty value change when the change of the drive signal with respect to the set differential pressure is small. The slip control device for a fluid coupling according to claim 1, wherein the slip control device is also determined to be small.