JPH06100275B2 - Control method for direct coupling mechanism of fluid power transmission device - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct coupling mechanism (lock-up clutch or the like) capable of mechanically engaging and disengaging an input side and an output side of a hydraulic power transmission device such as a torque converter.

(Prior Art) As an automatic transmission used in an automobile or the like, a combination of a hydraulic power transmission device (for example, a torque converter) and a transmission mechanism has been conventionally known. However, since a fluid power transmission device such as a torque converter transmits power through a fluid, it is unavoidable that a slip occurs during power transmission, and this slip causes a problem of reducing fuel consumption. However, there is a problem that the engine speed is increased by the amount of slip and the engine noise is apt to be loud.

Therefore, in a transmission using a fluid power transmission mechanism such as a torque converter, conventionally, the input side and the output side (for example, the impeller and the turbine of the torque converter) can be directly mechanically disengaged. A direct coupling mechanism (lock-up clutch) is provided, and power transmission by a torque converter or the like is performed only when necessary at low speeds, gear shifts, etc., and in other cases, the lock-up clutch is operated to improve fuel economy.
It is often practiced to reduce engine noise.

When engaging or disengaging the lockup clutch, there is a method of turning it on and off, but not only turning the lockup clutch on and off, but also the lockup control control that puts it in a half-engaged state. It is often the case. Such control is performed in a predetermined operation region at a relatively low speed, and the lockup clutch is slipped with respect to the peak value of the torque fluctuation, rather than directly connecting the torque converter.
For example, the rotational speed ratio e of the input and output of the torque converter or the slip ratio (1-e) is calculated, and the actual measurement is performed so that the rotational speed ratio e does not become 1 or the slip ratio becomes 0 in the above predetermined operation region. This is done by feeding back the value. As such a control method, for example, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent Publication No. 61-286665.

The feedback control for bringing the lock-up clutch into the half-engaged state is performed in a region where the vehicle speed is low and engine speed is low and surges, humming noises and rattling noises are likely to occur. However, when the vehicle speed is high, even if the lockup clutch is completely engaged, since the engine rotation is high, there is no problem of such unpleasant noise.
Rather, by completely engaging the engine, the engine speed is reduced by the amount of slip, so that there is an advantage that the engine sound is quieter and the fuel consumption is improved. Also,
In terms of driving performance, it is in the high engine speed range, so it does not decrease, and in the range exceeding the engine torque peak, the torque tends to increase in response to the decrease in engine speed due to complete engagement. , The driving performance is rather improved.

Therefore, in the low vehicle speed range, the capacity control of the lockup clutch can be feedback-controlled so that a constant slip can be obtained, and in the high vehicle speed range, the lockup clutch can be controlled to be completely engaged. Many.

(Problems to be solved by the invention) Then, in the middle vehicle speed range, which is an intermediate range between the above-mentioned two controls, a certain slip is allowed at the time of accelerating running due to the requirement of running performance, and at the time of steady running (during cruising running) Is desired to be controlled so as to be completely engaged. To this end, during steady running, the engagement capacity of the lockup clutch (direct coupling mechanism) becomes the minimum value of the capacity required to hold it in a completely engaged state or a value slightly larger than this minimum value. It is desirable to hold the state so that it will slip when the transmission torque increases due to acceleration.

However, when the lockup clutch is completely engaged, the parameters indicating the slip amount of the lockup clutch (slip ratio, input / output rotation speed ratio e = output rotation speed / input rotation speed, etc.) do not change. The problem is that the control of the engagement capacity of the lockup clutch cannot be controlled based on the above parameters. It should be noted that, during steady running, a method of predicting and setting in advance a minimum value of the capacity required to hold the lock-up clutch in a completely engaged state or an engagement capacity that is slightly larger than this minimum value There is also, but this engagement capacity is individual difference,
There is a problem that it is difficult to perform appropriate control by the method based on the prediction setting because the variation due to the oil temperature difference is large.

From the above, the present invention makes it possible to appropriately control the engagement capacity of the lockup clutch in the medium vehicle speed range without being affected by variations in the engagement capacity due to individual differences, oil temperatures, and the like. It is an object of the present invention to provide such a control method.

B. Structure of the Invention (Means for Solving the Problems) As means for achieving the above object, in the control method of the present invention, the engagement by the direct coupling mechanism (lock-up clutch) is disengaged in accordance with the operating state. Region, feedback region for feedback control of the engagement capacity so that the parameter indicating the slip amount between the input side and the output side of the direct coupling mechanism is within a predetermined reference range, and the direct coupling mechanism is completely engaged during steady running However, the engagement capacity is controlled by dividing into a semi-tight area where the engagement capacity is controlled so as to slip during acceleration traveling and an on-area (tight area) where the direct coupling mechanism is completely engaged. In the control in, the latest value of the control value of the engagement capacity of the direct coupling mechanism when the above parameter becomes a value within a predetermined reference range is updated and stored as a learning value, In Mitaito region, the learning value fixed amount increase correction to determine a control value of the engaging capacity, configured to perform control of the engagement capacity of the direct mechanism using the control value.

(Operation) When such a control method is used, feedback control is performed so that a constant slip is always generated in the lockup clutch in the feedback region. Therefore, based on the control value of the engagement capacity at that time, In, it is possible to easily predict the increase in the engagement capacity required to completely engage the lockup clutch. Therefore, the latest control value of the engagement capacity in the feedback area is used to control the engagement capacity in the semi-tight area (that is, it is necessary to fully engage the direct coupling mechanism during steady running and slip it during acceleration running). It is possible to accurately predict a proper engagement capacity control value), and it is possible to perform good control even in the semitight region.

(Examples) Hereinafter, preferred examples of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a hydraulic circuit of a torque converter 5 having a lock-up clutch whose engagement capacity is controlled by the method according to the present invention. This torque converter 5
Has a lockup clutch 6 capable of directly connecting the impeller 5a and the turbine 5b.
Is controlled by a lock-up shift valve 20, a lock-up control valve 30, and a lock-up timing valve 40 which are operated according to the on / off operation of the first solenoid valve 7 and the duty ratio operation of the second solenoid valve 8. It

The lockup clutch 6 is actuated in accordance with the driving condition to improve drivability and fuel efficiency. The capacity of the lockup clutch 6 is controlled by the above three valves 20, 30, 40. It is controlled to seven regions, that is, the first semi-tight region, the second semi-tight region, the lock-up on region (tight region) and the deceleration lock-up control region.

In this circuit, the oil sucked from the oil sump 1 via the oil passage 101 and discharged from the hydraulic pump 2 to the oil passage 102 is brought to a predetermined line pressure by the regulator valve 3 connected via the branch oil passage 103. The pressure is adjusted and supplied to the clutch and brake for setting the shift speed via the oil passage 104. The oil passage 105 branched from the oil passage 104 is connected to the modulator valve 4, and the line pressure of the oil passage 105 is adjusted to the modulator pressure by the modulator valve 4 so that the oil passage 1
Supplied to 06.

First, consider the case where the first and second solenoid valves 7 and 8 are off. At this time, each orifice
Oil passages 7b and 8b communicating with the oil passage 106 via 7a and 8a are closed by the spools of the solenoid valves 7 and 8, and the oil passage 11
The modulator pressure P _M from the oil passage 106 acts on 0, 111, 112, 113. Therefore, the modulator pressure is applied to both ends of the lockup shift valve 20 via the oil passages 110, 113 and 111.
P _M acts and the spool 21 of the valve 20 is moved to the right in the figure.

This point will be described in detail. In this valve 20, the oil passage
Spool that receives hydraulic pressure from the first oil chamber 25a communicating with 113
The pressure receiving area of 21 A _1, the spool which receives the hydraulic pressure of the pressure receiving area of the spool 21 that receives the hydraulic pressure from the second oil chamber 25b communicating with the oil passage 110 from the third oil chamber 25c communicating with the A _2, the oil passage 111 _Assuming that the pressure receiving area of 21 is A ₃ , A ₁ = A ₂ … (1) Formula A ₃ × P _M <(A ₁ + A ₂ ) × P _M + F _S … (2) Formula A ₃ × P _M > A ₁ × P _M + F _S … Each value is set so that it becomes the expression (3) (F _S : pushing force of the spring 22). Therefore, when the modulator pressure P _M acts on all of the first to third oil chambers 25a to 25c, the spool 21 is moved to the right by the spring force F _S.

Further, the modulator pressure P _M acts on the left end of the lockup control valve 30 via the oil passage 112, and this valve
The spool 31 of 30 is moved to the right, and oil passages 113 and 114 and oil passage 11
The modulating pressure acts on both ends of the lockup timing valve 40 via 0, 116, and the spool 41 of the timing valve 40 is moved to the right by the bias of the spring 42.

At this time, the line pressure supplied from the regulator valve 3 to the oil passage 107 is supplied to the oil passage 108 via the groove portion of the spool 21 of the lockup shift valve 20, and the oil passage 108 releases the lockup clutch 6 from the release side. The clutch plate connected to the turbine 5b is supplied to the back pressure chamber 6a.
6b is separated from the case 5d connected to the impeller 5a, and the lockup clutch 6 is turned off.

The oil discharged from the torque converter 5 to the oil passage 131 is made to flow to the cooler oil passage 132 via the torque converter check valve 9, and the oil is discharged from the torque converter 5 to the oil passage 1.
The oil discharged to 33 is the lock-up shift valve 20
Cooler oil passage 1 from the groove of spool 21 via oil passage 134
It is flowed to 32, then passes through the oil cooler 11, is cooled, and is returned to the oil sump 1 via the oil passage 135. Also, to protect the cooler oil passage 132 and the cooler 11,
The cooler relief valve 10 is connected to the cooler oil passage 132.

Next, consider a case where the lockup clutch is in a half-engaged state. This state is one in which the engagement capacity of the lockup clutch is controlled in accordance with the increase in vehicle speed and engine output, and is generated by turning on the first solenoid valve 7 and controlling the duty ratio of the second solenoid valve 8. When the first solenoid valve 7 is turned on, the modulator pressure in the oil passage 110 acting on the left end of the shift valve 20 is released. At this time, the spool 21 is moved to the left because each value is set as in the equation (3). When the spool 21 is moved to the left, the supply direction of the line pressure from the oil passage 107 is switched to the oil passage 133, the line pressure is supplied from the oil passage 133 into the torque converter 5, and the internal pressure of the torque converter 5 is increased. Becomes higher. As a result, the clutch plate 6b of the lockup clutch 6 is engaged (that is, the case is
Back side pressure is generated in the release side back pressure chamber 6a by being pushed by the side contacting the side surface of 5d).

For torque converter internal pressure, use the clutch plate 6b as a case.
The back pressure acts in a direction of engaging with 5d, and the back pressure acts in a direction of releasing the back pressure.The release side back pressure chamber 6a in which this back pressure is generated is located in the oil passage 108 and the spool of the lockup shift valve 20. The lockup control valve 30 is connected via a groove 21 and an oil passage 115, and the spool 31 of the control valve 30 receives a pushing force to the left due to the back pressure of the torque converter 65.

Since the oil passage 110 also communicates with the oil passage 116, the oil pressure acting on the right end of the lockup timing valve 40 disappears, but the spool 41 of this valve 40 has already been moved to the right and remains as it is. Retained.

On the other hand, when the duty ratio of the second solenoid valve 8 is controlled, the oil pressure in the oil passages 112, 113 is controlled according to this duty ratio, and the duty ratio control oil pressure is lower than the modulator pressure in the oil passage 106. The duty ratio control hydraulic pressure is a hydraulic pressure that decreases as the ratio of the on-duty signal increases, and for example, the on-duty signal increases as the vehicle speed increases.

Here, the spool 31 receives the duty ratio control hydraulic pressure at the left end thereof via the oil passage 112, but this control hydraulic pressure is reduced in accordance with the increase of the on-duty signal, and the spool 31 receives the duty ratio control hydraulic pressure at the right end. The pushing force to the direction fluctuates according to the duty ratio. Further, the spool 31 receives the torque converter internal pressure at the left end thereof via the oil passages 117 and 118 and is pushed rightward. Therefore, the torque converter back pressure acting on the right end and the biasing force of the spring 32, and the duty ratio control hydraulic pressure and the torque converter internal pressure acting on the left end act on the spool 31, and the torque converter back pressure changes the duty ratio control. It changes according to the oil pressure. That is, the torque converter back pressure is controlled by changing the duty ratio control hydraulic pressure, and the engagement capacity of the lockup clutch 6 is controlled.

The lockup control state is obtained as described above. In this state, the second solenoid valve 8
From the state where the on-duty signal of 100% becomes 100% (that is, the state where the second solenoid valve 8 is on),
When the solenoid valve 7 is switched off, a full lockup condition is created. When the first solenoid valve 7 is turned off, the modulated pressure acts on the right end of the lockup timing valve 40 from the oil passages 110 and 116. At this time, since the second solenoid valve 8 is in the ON state, the oil pressure in the oil passages 113 and 114 is zero, and the spool 41 of the timing valve 40 is moved to the left. Therefore, the oil passage 118 is communicated with the drain, the spool 31 of the lock-up control valve 30 is held in the completely left position, and the release side back pressure chamber 6a of the torque converter 5 is drained via the oil passages 108, 115. By communicating, the torque converter back pressure becomes zero. As a result, the lockup clutch 6 is completely engaged.

As described above, when the first solenoid valve 7 is turned on /
The capacity control of the lockup clutch 6 can be performed only by the off control and the duty ratio control of the second solenoid valve 8. Here, a specific operating state when the capacity control is performed is shown in FIG. The description will be made based on the graph.

In FIG. 2, the vertical axis represents the throttle opening and the horizontal axis represents the vehicle speed, and the regions on both axes are divided into two by the lock-up on operation line m (solid line). This on-operation line m
The region on the left side is the off region A, and when the operating state determined by the throttle opening and the vehicle speed is within this off region A, the lockup clutch 6 is controlled to be off, and the operating state is the off region. When the vehicle moves from A to the on-operation line m and moves to the lock-up region on the right side of the line m, engagement control of the lock-up clutch 6 is started. Further, the lock-up off operation line n is provided with a certain hysteresis on the lower vehicle speed side than the on-operation line m, and after the operating state shifts to the lock-up region, the lock-up off operation line n When it crosses, the lockup clutch 6 is turned off and shifts to the off region A.

The lock-up area is further indicated by a chain line 5 in the figure.
The book is divided into five by lines a to e, and as a result, the feedback area B, the control area C, the first area
A semitight region D, a second semitight region E and a tight region F are formed. A deceleration lockup region G is formed as a region where the throttle opening becomes substantially zero and the vehicle speed is equal to or higher than a predetermined vehicle speed (about 25 km / H).

The capacity of the lock-up clutch 6 is controlled according to the area formed as described above. An outline of the control content will be described first with reference to the flow chart of FIG.

In this control, first, the lockup off time is determined in step S1. This judgment is based on manual shifting, that is, manual operation of the shift lever, normal
This is for turning off the lockup clutch for a certain period of time when the speed is changed by a switching operation of the power mode changeover switch or the like. Next, in step S2, it is determined whether or not the lockup clutch is off when automatic gear shifting is performed. Here, when automatic shift is performed, whether the upshift or the downshift detects the throttle opening degree, etc., and based on these, it is determined whether or not the lockup is performed. After that, the process proceeds to step S3, and it is determined whether the lockup should be turned off when the oil temperature of the torque converter is extremely low or extremely high. Then, in any of the above steps, when it is determined that the lockup needs to be turned off, the process proceeds to step S8, and the lockup clutch is turned off.

Next, in step S4, it is determined whether or not the vehicle is in a decelerating state based on the changes in the vehicle speed and the throttle opening.If the vehicle is in the decelerating state, in step S5, deceleration is performed according to the oil temperature, the vehicle speed, and the engine speed. It is determined whether or not lockup control is performed, and if necessary, the process proceeds to step S8, and lockup is turned off.

If it is determined that the vehicle is not in the deceleration state, it is determined in step S6 which region the operating state is on the map shown in FIG. 2, and the first and second solenoid valves 7, 8 are determined according to this region. Is controlled (step S
7).

Next, the control in step S7 will be described in detail below with reference to the flow chart of FIG.

In this control, in steps S10 to S30, which region the operating state is in is determined from the lockup zone code KZ. This zone code KZ is a number assigned according to each area when the determination is made in step S6 of FIG. 3, and the off area A is KZ = 0 and the deceleration lockup area G is
KZ = 1, KZ = 2 in the feedback region B and the control region C, KZ = 3 in the first semi-tight region D, KZ = 4 in the second semi-tight region E, KZ = 5 in the tight region F.
Is. However, the process proceeds to step S6 only when the operating state is in the lockup region, and is when KZ = 2, 3, 4, or 5.

First, when it is determined in step S10 that KZ = 2, the operating state is in the feedback region B or the control region C. In this case, step S1
Go to 1. In this step S11, it is determined whether or not a predetermined delay time LD2 has elapsed since the operating state shifted from the off region to these regions B and C. This is because the lockup operation is performed with a certain time delay when the operating state shifts from the off area A to the lockup area. Therefore, the delay timer LD
Until this time, the value of T becomes longer than the delay time LD2, the current flow is terminated.

When LDT ≧ LD2, the learning value D _OS calculated and stored in the next step S13 is stored as the off duty ratio D _OM (step S12), and the second solenoid valve 8
The feedback component for controlling the duty ratio of is determined (step S13). Next, at step S14, the Zon control for preventing the shock due to the abrupt change of the duty ratio is made to moderate the abrupt change of the duty ratio due to the transition of the region and the like. Further, in the control of the feedback region B or the control region C, it is necessary to turn on the first solenoid valve 7 as described above, so a command to turn on the first solenoid valve 7 is issued in step S15, End the flow.

Here, the control for determining the feedback component for controlling the duty ratio of the second solenoid valve 8 in step S13 will be described before proceeding to the following steps.

In this control, as shown in FIG. 5, first, in step S5
Make the judgment shown in 1 to 55. In step S51, it is determined whether or not 1 is set in the feedback inhibition flag Fep, and if 1 is set, the process proceeds to step S57.

In step S52, it is determined whether the throttle opening TH is larger than the cruise determination throttle opening THCR. This cruise determination throttle opening THCR is the same as the throttle opening of the chain line a that divides the feedback area B and the control area C in FIG.
THCR means that the operating condition is within the control range C, and in this case, the process proceeds to step S57.

In step S53, it is determined whether or not the brake is operated, and if it is in operation, step S5
Proceed to 7.

In step S54, it is determined whether or not the temperature range code NT is 2, and if NT ≠ 2, step S5
Proceed to 7. This temperature range code NT is set to a value in 5 steps from 0 to 4 according to the torque converter oil temperature,
They indicate extremely low temperature, low temperature, normal temperature, high temperature and extremely high temperature, respectively. Here, in the case of extremely low temperature and extremely high temperature (when NT = 0 and 4), the lockup is turned off in step S3 of FIG. 3, and therefore, it is NT = In the case of 1 to 3, if NT = 2 (at room temperature), proceed to step S55, and if NT = 1 or 3 (at low temperature or high temperature), proceed to step S57.

In step S55, it is determined whether the engine cooling water temperature TW is higher than the feedback control permission temperature DTW. If it is lower than this permission temperature DTW, the process proceeds to step S57, and if it is higher than this, the process proceeds to step S56.

When the process proceeds from the above judgment step to step S57, the correction permission flag F _CR is set to 0 in step S57, and the sampling counter value P is set to zero in steps S58 and 59 to set the speed ratio integrated value. Set Σe to zero. As can be seen from the determination in step S52, the process proceeds to step S57 when it is in the control region. In this case, the off-duty value D _OM of the second solenoid valve 8 is set to the step shown in FIG. It becomes the latest learning value D _OS stored in S12.

On the other hand, the case of proceeding to step S56 is in the case of the feedback region, but in this case, feedback control by Ce control is performed. This step S56
The contents of the Ce control shown in FIG. 6 will be described with reference to FIGS. 6 to 11.

This C-e control is, as shown in FIG. 6, an average speed ratio calculation routine ea for calculating the average value of the input / output rotation speed ratio e of the lockup clutch for each average value calculation time T _CR.
VCAL (step S61) and (in the range of e _L to e _H, corresponds to a predetermined reference range referred to in the claims) the average velocity ratio eav and the target speed ratio range calculated here speed based on the difference between The eav correction routine (step S62) for correcting the duty ratio so that the ratio e falls within the target speed ratio range, and the speed ratio e above the upper limit value e _H for a predetermined time Te _H e _H correction routine for correcting the duty ratio in real time back to the speed ratio range (step S63)
And a D _OS update routine (step S64) for updating the latest value of the duty ratio obtained in the above routine as necessary and storing this as the learned value D _OS .

Before explaining the above routines (steps S61 to S64),
The outline of these controls will be described with reference to FIG. 7 showing changes in the speed ratio e due to these controls.

In FIG. 7, the vertical axis represents the speed ratio e, the horizontal axis represents time, and the solid line in this graph shows the change in the actual speed ratio e. Target speed ratio range is between the lower limit speed ratio e _L indicated by a dashed line, respectively (e.g., e _L = 0.95) and the upper limit speed ratio e _H (e.g., e _H = 0.98), averaging Average speed ratio eav calculated for each time T _CR (values indicated by bold lines in the figure)
Based on the difference between the target speed ratio range value and the target speed ratio range value, the speed ratio e is controlled to fall within the target speed ratio range (step S6).
2 control).

When the actual speed ratio e exceeds the upper limit speed ratio e _H during this control, the speed ratio e becomes very close to 1.0 (complete lockup), and tends to become 1.0. When the speed ratio becomes 1.0 and the vehicle is completely locked up, engine vibration may be transmitted to the drive system and the vehicle body in a state where the operating condition is within the feedback region B, and muffled noise may be generated. It is desirable to reliably prevent the increase, and for this reason, when the speed ratio e exceeds the upper limit value e _H for a predetermined time Te _H or more, it is not the control by the average speed ratio eav as described above but Based on the speed ratio e at the time point, the duty ratio setting control for keeping the speed ratio e within the target range in real time (step S63
Is controlled).

In the above control, the duty ratio corrected based on the average speed ratio eav is updated each time the value becomes appropriate and stored as the learning value D _OS (step S64).

The flow chart of FIG. 8 shows the contents of the routine of step S61. Here, it is first determined whether or not the sampling timer T _SP has become zero (step S7
0), when it becomes zero, the process proceeds to step S71, and it is determined whether or not the value of the sampling counter P has reached the sampling number a. The sampling timer T _SP is a cycle interval at which the speed ratio is detected, and the average speed ratio eav is calculated by detecting the sampling times a times in this cycle and averaging them, and the average value calculation time is calculated. T _CR = T _SP × a.

Therefore, until the value of the sampling counter P reaches a, the process proceeds to step S72 and increments the value of the counter P by 1 every cycle of the sampling timer T _SP , and the previous speed ratio integrated value Σe is added to the detected speed ratio of this time. e (P) is added to obtain the current speed ratio integrated value Σe. As a result, P = 0 to P = (a
Up to -1) (during T _CR ), the sum of the speed ratios e (P) a times, that is, the integrated value Σe of the speed ratio e during the average value calculation time T _CR is the average value calculation time T. _{Separated for} each _CR .

Then, when P = a, the process proceeds from step S71 to step S74, and the speed ratio integral value Σe obtained as described above is divided by the number of times a of sampling, and the average value calculation time T _CR at this time is calculated. Calculate the average speed ratio eav of.
Thereafter, in order to calculate the average speed ratio at the next average value calculation time T _CR , the sampling counter P and the speed ratio integrated value Σe are calculated.
Is set to zero, and further, the correction timing flag F _C e and the correction permission flag F _CR are set to 1 in response to the calculation of the average speed ratio eav (steps S75 to 78).

Next, an eav correction routine (step S to correct the duty ratio using the average speed ratio ea _V obtained as described above)
62) will be described with reference to the flowchart of FIG.

In this flow, it is not judged whether or not the correction permission flag F _CR is 1 (step S80), and when it is 0,
The learning value update timer TD _OS is set to zero (step S8
1). Further, it is judged whether or not the correction timing flag F _C e is 1 (step S82), and when it is zero, this flow is finished as it is.

When it is 1, it is determined in step S83 whether the average speed ratio eav is larger than the upper limit speed ratio e _H shown in FIG. 7, and if eav> e _H , the process proceeds to step S88. In step S88, the difference between the average speed ratio eav and the upper limit speed ratio e _H is multiplied by a predetermined coefficient β to obtain the weak correction value X _H, and the off duty ratio D for the previous operation control of the second solenoid valve 8 is calculated. A new off-duty ratio D obtained by adding the weak correction value X _H to the control unit is stored as the control duty ratio during the current average value calculation time T _CR (step S89). As a result, the engagement capacity of the lockup clutch is reduced by the amount corresponding to the weak correction value X _H, and the speed ratio that is greater than the upper limit speed ratio e _H is reduced to reduce the target speed ratio. Make it correct within the range. Next, the learning value update timer TD _OS is set to zero (step S90), the correction timing flag Fce is set to zero (step S92), and the correction determination time Te _H is set to the initial value for the next flow (step S92). S93), this flow ends.

On the other hand, in step S83, the if it is determined that eav ≦ e _H, the process proceeds to step S84, the been made eav <e _L determines whether, in the case of eav <e _L, the process proceeds to step S85. Step
In S85, obtains the intensity correction value X _L by multiplying a predetermined coefficient α to the difference between the lower limit speed ratio e _L and average speed ratio eav, from off-duty ratio D for operation control of the second solenoid valve 8 of the preceding The new off-duty ratio D obtained by subtracting the strong correction value X _L is stored as the control duty ratio during the current average value calculation time T _CR (step S86). As a result, the engagement capacity of the lockup clutch is
It would be increased by that amount corresponding to X _L, which is corrected toward the target speed ratio range by increasing the speed ratio becomes smaller than the upper limit speed ratio e _L. Next, the learning value update timer TD _OS is set to zero (step S87), and Fce and Te
The setting of _H is made (steps S92, 93), and this flow ends.

If it is determined in step S84 that eav> e _L ,
Since the average speed ratio e _A v is within the target speed ratio range, the routine proceeds to step S91, the value of the learning value update timer TD _OS is incremented by 1, and Fce and Te _H are set (steps S92, S9
3), this flow ends.

Next, the e _H correction routine shown in step S63 of FIG. 6 will be described with reference to the flowchart of FIG.

Also in this control, it is first determined whether or not the correction permission flag F _CR is 1 (step S101), and if it is zero, the process proceeds to step S110 to set the e _H correction determination time Te _H to the initial value. If F _CR = 1 is determined in step S102 whether the actual speed ratio e at that time is larger than the upper limit speed ratio e _H. When e ≦ e _H, the process proceeds to step S110, and the e _H correction determination time Te _H is set to the initial value.

When e> e _H , it is determined whether or not the e _H correction determination time Te _H has become zero (has increased). The increase of this means that the state of e> e _H has continued for the e _H correction determination time (predetermined time) Te _H or more, and at this time, the control of step S104 and thereafter is performed. It should be noted that if the determination time Te _H has not risen, the current flow ends as it is.

In step S104, a predetermined correction amount D _H is added to the off duty ratio D of the second solenoid valve 8 in order to reduce the engagement capacity of the lockup clutch and reduce the speed ratio e to the upper limit value e _H or less. To correct. After this, in steps S105 and 106, the values of the sampling counter P and the speed ratio integrated value Σe are set to zero, and step S1
At 07, the sampling timer T _SP is set. Further, in step S108, the Zon control permission flag FZ is set to 0, and for the e _H correction, the correction is performed immediately without performing the Zon control, and in step S109, the learning value update timer TD _OS is set to zero. To do. After this step
In S110, set e _H correction judgment time Te _H to the initial value,
This flow ends.

The D _OS update routine which is step S64 of FIG. 6 is shown in the flowchart of FIG. Here, Zon permission flag F
It is determined whether Z is 1 (step S121) and whether the learning value update timer TD _OS has exceeded the update determination time DD _OS (step S122), the Zon control is not executed, and When the speed ratio e is within the target speed ratio range while the update determination time is DD _OS or more, in step S123,
The off-duty ratio D at this time is stored as the learning value D _OS . Therefore, the off duty ratio D _OM stored in step S12 of FIG. 4 is the latest learning value D _OS ,
Since the speed ratio e is maintained within the target speed ratio range, it becomes the most appropriate value at that time.

In the above, the control in the case where the operating state is in the feedback region B or the control region C has been described, but in the case of being in the first semitight region D, the second semitight region E or the tight region (on region) F other than this. The control will be described by returning to FIG.

When the operating condition is in the feedback region B or the control region C, the zone code KZ = 2, and the control was performed by proceeding from step S10 to step S11. However, when KZ ≠ 2, the process proceeds to step S20. move on.

If it is determined in step S20 that KZ = 3, the operating state is within the first semi-tight region D, and in this case, the process proceeds to step S21, where the operating state is within this region D depending on the value of the delay timer LDT. After waiting for a predetermined delay time LD3 from step S22, the process proceeds to step S22. In step S22, the value obtained by subtracting the constant value D ₁ from the latest learned value D _OS is stored as the off-duty value D _OM . Here, the learning value D _OS is also a value indicating the off-duty ratio, and reducing the constant value D ₁ means increasing the on-duty ratio,
As a result, in the first semitight region, the learning value D
_The off-duty value D _OM is set to a value that makes the capacity increased by a certain amount from the engagement capacity of the lockup clutch based on the _OS .

Here, the engagement capacity of the lockup clutch in the first semi-tight range is set so that the lockup clutch is completely engaged during normal traveling but slips during acceleration traveling. is there. Therefore, although the capacity is increased by a certain amount as described above, the learning value D _OS is, as described above, for maintaining the speed ratio e within the predetermined reference range when in the feedback region. This is the latest value of the duty ratio, and this learning value D _OS
If the capacity is increased by a certain amount, the optimum engagement capacity can be set easily and surely at that time.

Next, when the duty ratio set in this way is immediately used, in order to prevent a sudden change in the duty ratio and a shock from occurring, in step S23, Z
The on control is performed and the correction for smoothing the change of the duty ratio is added. Also in this region, the first solenoid valve 7 must be turned on, so step S2
In step 4, a command for this is output, and this flow ends.

If it is determined in step S30 that KZ = 4, the operating condition is within the second semi-tight region E,
In this case, the process proceeds to step S31, and the predetermined delay time is set after the shift to the area D by the value of the delay timer LDT.
After waiting for LD4, the process proceeds to step S32. In step S32, the off-duty value D _OM is set to zero (that is, the on-duty value is set to 100%), and the step S32
At 33 and 34, the same Zon control as above and the output of the ON command to the first solenoid valve 7 are performed, and the current flow is ended.

Furthermore, when it is determined that KZ ≠ 4 in step S30, KZ = 5, so the operating state is in the tight region (lock-up on region) F. In this case, step S4
After proceeding to 0 and waiting for a predetermined delay time LD5 after shifting to the area D according to the value of the delay timer LDT, the process proceeds to step S41. In step S41, the off-duty value D _OM is set to zero, and in step S42, the same Zon control as described above is performed.

Next, in step S43, it is determined whether the Zon execution flag FZ is 1. This Zon execution flag FZ is set to 1 while the duty ratio is corrected by the Zon control, and waits until this flag FZ becomes 0.
That is, waiting for the above correction to be completed, step S44
Then, a command for turning on the second solenoid valve 8 is output.

Then, in step S45, the solenoid-on timer T
_It is determined whether or not _Z1 has become zero, and the first solenoid valve 7 is kept on until it becomes zero (step S46), and when the timer T _Z1 becomes zero, 1 A command to turn off the solenoid valve 7 is output (step S47). That is, the tight state (lock-up ON state) is created by switching the first solenoid valve 7 from ON to OFF, and this switching is performed after waiting for a certain period of time.

The duty ratio of the second solenoid valve 8 is determined by the control described above. Since the duty ratio is controlled so that the speed ratio e falls within a predetermined reference range, if the engine torque component fluctuates. The lockup engagement capacity is controlled to be changed according to this change so that the speed ratio e falls within the above range. Therefore, the duty ratio determined as described above is a value including a component corresponding to the engine torque, and for example, the same speed ratio is obtained in the case of traveling on a slope and the case of traveling on a flat road. The duty ratio required for this is different.

Therefore, in the present control, the component corresponding to the engine torque (this is referred to as the engine torque component) is subtracted from the duty ratio determined as described above, and the remaining component (this is referred to as the feedback component). The lockup engagement capacity is estimated and set on the basis of the above.

This will be described with reference to FIG. As an example, 50
Consider setting the duty ratio during normal driving at km / H. In this case, if the engine torque is 4 kg-m and the learning value of the feedback component is 20% (on side),
As can be seen from the figure, the engine torque component is 20%, and the feedback component is 50 × (20/100) = 10%. For this reason, the on-duty ratio of the second solenoid valve 8 in this case is 30% in total of both components. When the operating state is in the first semi-tight range, a value obtained by adding a fixed value to the learning value is used as the feedback component.

Here, the control contents of the solenoid valve for each area
Organize based on the table in the figure. When the operating state is in the off region, the first solenoid valve 7 and the timing valve valve 8 are off, and the second solenoid valve 8 is also OF.
F, that is, 0% on-duty. In the feedback area, the first solenoid valve 7 is turned on.
The second solenoid valve 8 is controlled by the duty ratio set by the sum of the feedback component determined based on the feedback control and the engine torque component determined corresponding to the engine torque at that time. In the control region, the latest learning value stored in the feedback control becomes the feedback component, and control is performed by the duty ratio set by the sum of this and the engine torque component corresponding to the engine torque. In the first semi-tight range, control is performed by the duty ratio set by the sum of the feedback component obtained by adding a constant value for increasing the engagement capacity to the latest learned value and the engine torque component. In the second semi-tight region, the first solenoid valve 7 is turned on and the second solenoid valve
The feedback component of the solenoid valve 8 is ON
The value becomes 100%, the value corresponding to the engine torque is used as the engine torque component, the duty ratio is set by the sum of both components, and the timing valve 40 is kept OFF. And in the tight region, the first solenoid valve 7
The timing valve 40 is turned off and the timing valve 40 is turned on.

In the above embodiment, the second solenoid valve 8
An example of using the speed ratio of the input / output rotation speed of the lockup clutch was shown when determining the control duty ratio.
Instead of the speed ratio, the difference between the input and output rotational speeds may be used for the determination. Further, a proportional electromagnetic valve may be used in place of the solenoid valve whose duty ratio is controlled as described above. In this case, current value control is performed instead of duty ratio control.

Further, in the above-described embodiment, the example in which the torque converter is used as the fluid type power transmission device is shown, but other types of fluid type power transmission mechanism such as fluid coupling may be used.

C. As described above, according to the control method of the present invention, since the engagement capacity of the lockup clutch is feedback-controlled so that a constant slip is always generated in the feedback region, the lockup clutch is locked at that time. The increase in the engagement capacity required to fully engage the up-clutch can be easily predicted, and therefore, the latest control value of the engagement capacity in the feedback area is used to determine the engagement capacity in the semi-tight area. The control value of can be accurately predicted, and good control can be performed even in the semitight region.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram around a torque converter having a lockup clutch whose engagement capacity is controlled by the method of the present invention, and FIG. 2 is engagement of the lockup clutch from the relationship between throttle opening and vehicle speed. Graphs showing the regions, FIGS. 3 to 6 and 8 to 11 are flow charts showing the contents of solenoid valve actuation control for performing actuation control of the lockup clutch, and FIG. 7 is a graph showing the speed ratio of the lockup clutch and time. A graph showing an example of the relationship, FIG. 12 is a graph showing the relationship between the duty ratio of the solenoid valve and the engine torque, and FIG. 13 is a table showing the control contents of the solenoid valve for each region. 1 …… Oil sump, 2 …… Hydraulic pump 3 …… Regulator valve, 5 …… Torque converter 6 …… Lockup clutch 7,8 …… Solenoid valve, 11 …… Oil cooler 20 …… Lockup shift valve 30… … Lockup control valve 40 …… Lockup timing valve

Claims (1)

[Claims] 1. A method for controlling an engagement capacity of a direct coupling mechanism which is disposed between an input side and an output side of a fluid type power transmission device and mechanically engages and disengages the input side and the output side. According to the operating state, the parameter indicating the off region where the engagement by the direct coupling mechanism is disengaged and the slip amount between the input side and the output side is within a predetermined reference range. The feedback area for feedback control of the combined capacity, the semi-tight area for setting the engagement capacity so that the direct coupling mechanism is fully engaged during steady traveling but slips during acceleration traveling, and the direct coupling mechanism is always completely engaged. In the method of controlling the engagement capacity separately from the ON area, the engagement capacity when the parameter becomes a value within the predetermined reference range in the control in the feedback area. The latest value of the control value is updated and stored as a learning value, and in the semi-tight region, the learning value is corrected by increasing by a certain amount to determine the control value of the engagement capacity, and the engagement value is determined using this control value. A method for controlling a direct coupling mechanism of a fluid type power transmission device, which comprises controlling a capacity.