JPH01283468A - Direct coupling mechanism control method for hydraulic power transmission device - Google Patents

Abstract

PURPOSE:To enable the pertinent control of the engagement capacity of a lock-up clutch in a medium speed region by predicting properly the control value of engagement capacity in a semi-tight region. CONSTITUTION:A feedback control is made for generating a constant slip on a lock-up clutch 6 at all times in a feedback region. It is easy to predict an increment in engagement capacity then necessary by the time of the full engagement of the lock-up clutch 6 when based upon the control value of the capacity then available. Consequently, it becomes possible to predict properly the control value of engagement capacity in a semi-tight region, using the latest control value of engagement capacity in the feedback region, and it is also possible to make a proper control even in the semi-tight region.

Description

Detailed Description of the Invention A.3 Objective of the Invention (Field of Industrial Application) The present invention provides a mechanically disconnectable direct connection between the input side and the output side of a hydraulic power transmission device such as a torque converter. Regarding mechanisms (lock-up clutches, etc.).

(Prior Art) As automatic transmissions used in automobiles and the like, automatic transmissions that combine a fluid power transmission device (for example, a torque converter) and a transmission mechanism are conventionally known. However, since hydrodynamic power transmission devices such as torque converters transmit power through fluid, they cannot avoid slipping during power transmission, and this slipping causes problems such as reduced fuel efficiency and problems. There is a problem that the engine speed increases by the amount of slip and the engine noise tends to become louder.

For this reason, in transmissions using hydraulic power transmission mechanisms such as torque converters, input and output sides (
For example, a direct coupling mechanism (lock-up clutch) that can directly mechanically engage and disengage the impeller and turbine of the torque converter is installed, and power transmission by the torque converter etc. is performed when necessary, such as at low speeds or when changing gears. In other cases, it is common practice to operate the lock-up clutch to improve fuel efficiency and reduce engine noise.

When controlling the engagement and disengagement of this lock-up clutch, there is a method of controlling it on and off, but in addition to turning the lock-up clutch on and off, there is also a lock-up control control that puts it in a semi-engaged state. I often have to do it. Such control is performed in a predetermined operating range at relatively low speeds, and instead of directly connecting the torque converter, the lock-up clutch is slipped in response to peak torque fluctuations.
For example, calculate the input/output rotation speed ratio e or slip ratio (1-e) of the torque converter, and use these actual measurements to ensure that the rotation speed ratio e does not become 1 or the slip ratio becomes 0 in the above-mentioned predetermined operating range. This is done by feeding back the value. Such a control method is disclosed, for example, in Japanese Patent Laid-Open No. 61-286665.

Feedback control such as this to bring the lock-up clutch into a semi-engaged state is performed in a relatively low vehicle speed range where the engine rotation is low and surges, crashing noises, and rattling noises are likely to occur. However, at high vehicle speeds, even if the lock-up clutch is fully engaged, the engine rotation is still high, so there is no problem of generating such unpleasant noises.
Rather, by completely engaging the clutch, the engine rotation will be reduced by the amount of slip, which has the advantage of making engine noise quieter and improving fuel efficiency. Also,
Since this is a high engine speed range in terms of driving performance, this does not decrease, and in the range above the engine's torque peak, torque tends to increase in response to the decrease in engine speed due to full engagement. Driving performance actually improves.

For this reason, it is recommended that the capacity control of the lock-up clutch be feedback-controlled to obtain a constant slip in the low vehicle speed range, and that the lock-up clutch be fully engaged in the high vehicle speed range. many.

(Problem to be Solved by the Invention) In the medium vehicle speed region, which is the intermediate region between the above two controls, due to the requirements for driving performance, a certain amount of slip is allowed during acceleration driving, and a fully engaged slip is allowed during normal driving. It is desirable to control the condition so that the condition is met. For this purpose, during normal driving, the engagement capacity of the lock-up clutch (direct coupling mechanism) must be at the minimum value required to hold it in a fully engaged state, or at a value slightly larger than this minimum value. It is desirable to maintain this condition so that it slips when the transmitted torque increases during acceleration.

However, when the lock-up clutch is fully engaged, the parameters representing the slip amount of the lock-up clutch (slip ratio, input/output rotation speed ratio e - output rotation speed/input rotation speed, etc.) do not change. However, there is a problem in that the engagement capacity of the lock-up clutch cannot be controlled based on the above parameters. In addition, during normal driving, the engagement capacity is predicted and set in advance to be the minimum value of the capacity required to hold the lock-up clutch in a fully engaged state, or a value slightly larger than this minimum value. There are other methods, but this engagement capacity varies from individual to individual.
There is a problem that there are large variations due to differences in oil temperature, etc., and it is difficult to perform appropriate control using a method based on predictive setting.

Therefore, the present invention makes it possible to appropriately control the engagement capacity of the lock-up clutch in the medium vehicle speed range without being affected by variations in engagement capacity due to individual differences, oil temperature, etc. The purpose is to provide a control method that allows

Structure of the invention (means for decomposing the problem) As a means for achieving the above object, in the control method of the present invention, a direct coupling mechanism (lock-up clutch) is disengaged depending on the operating state. Off area and direct connection 1
A feedback area that feedback-controls the engagement capacity so that the parameter representing the amount of slip between the input side and output side of the 11 mechanisms is within a predetermined reference range, and a direct coupling mechanism that engages during normal driving, but during acceleration driving. The engagement capacity is controlled by dividing it into a semi-tight area where the engagement capacity is controlled so that it sometimes slips, and an on area (tight area) where the direct coupling mechanism is fully engaged, and control in the feedback area. , the control value of the engagement capacity of the direct coupling mechanism in the semi-tight region is determined based on the control value of the engagement capacity of the direct coupling mechanism when the above-mentioned variation reaches a value within a predetermined reference range. .

(Function) When such a control method is used, feedback control is performed so that a constant slip is always generated in the lock-up clutch in the feedback region, so based on the control value of the engagement capacity at that time, The increase in engagement capacity required to completely engage the lock-up clutch can be easily predicted. Therefore, the engagement capacity control value in the semi-tight area can be accurately predicted using the latest value of the engagement capacity control value in the feedback area, and it is possible to perform good control even in the semi-tight area.

(Example) Preferred examples of the present invention will be described below with reference to the drawings.

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 lock-up clutch 6 that can directly connect an impeller 5a and a turbine 5b.
The lock-up shift valve 20 is operated in accordance with the off operation and the duty ratio operation of the second solenoid valve 8.
, a lockup control valve 30 and a lockup timing valve 40.

This lock-up clutch 6 is operated according to driving conditions to improve drivability and fuel efficiency.The three valves 20, 30 and 40 control the capacity of the lock-up clutch 6, which is controlled by the lock-up-off area, feedback area, and control area. It is controlled into seven areas: a first semi-tight area, a second semi-tight area, a lock-up-off area (tight area), and a deceleration lock-up control area.

In this circuit, oil is sucked from an oil sump 1 through an oil path 101 and discharged from a hydraulic pump 2 to an oil path 02, which is maintained at a predetermined line pressure by a regulator valve 3 connected through a branch oil path 103. The pressure is regulated and supplied to the clutch and brake for gear setting via the oil passage 104. Further, an oil passage 105 branched from the oil passage 104 is connected to a modulator valve 4, and the line pressure of the oil passage 105 is regulated to a modulator pressure by the modulator valve 4, and then supplied to the oil passage 106.

First, consider the case where the first and second solenoid valves 7.8 are off. At this time, the oil passage 7 communicates with the oil passage] and 06 via the orifices 7a and 8a, respectively.
b, 8b are blocked by the spool of the solenoid valve 7.8, and the oil passage 110.1 ], 1. ], 12,1
Modulator pressure PM from oil passage 106 acts on 13. This lick, oil passages 110, 113 and oil passage 111
Modulator pressure PM acts on both ends of the lock-up shift valve 20 through the spool 21 of this valve 20.
has been moved to the right in the figure.

This point will be explained in detail. In this valve 20, the pressure receiving area of the spool 21 which receives the hydraulic pressure from the first oil chamber 25a communicating with the oil passage 113 is A1, and the pressure receiving area of the spool 21 which receives the hydraulic pressure from the second oil chamber 25b communicating with the oil 18110 is A1. A2, where A3 is the pressure receiving area of the spool 21 that receives oil pressure from the third oil chamber 25c communicating with the oil passage 111, AI = A2 (1)
Formula % Formula %...(21 Formula A3 X PM > AlX PM +F s -(
3) Each part is set so that the formula is satisfied (however, Fs
(pushing force of spring 22). Therefore, when the modulator pressure P@ 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 Fs.

Further, the modulator pressure PM acts on the left end of the lock-up control valve 30 via the oil passage 112, and the spool 31 of this valve 30 is moved to the right, causing the oil passages 113, 1
Modulator pressure acts on both ends of the lock-up timing valve 40 through the oil passages 1, 14 and 10, 116, and the spool 41 of the timing valve 40
Due to the bias of 2, it moves to the right.

At this time, the line pressure supplied from the regulator valve 3 to the oil passage 107 is transferred to the lock-up shift valve 20.
is supplied to the oil path 108 through the groove of the spool 21,
Since oil is supplied from the oil passage 108 into the releasing side back pressure chamber 6a of the lock-up clutch 6, the clutch plate 6b connected to the turbine 5b is separated from the case 5d connected to the impeller 5a, and the lock-up clutch 6 is released. The oil discharged from the torque converter 5 into the oil passage 131 is in the off state 6. The oil discharged from the torque converter 5 into the oil passage 131 is flowed into the cooler oil passage 132 via the torque converter check valve 9, and the oil discharged from the torque converter 5 into the oil passage 133 is , flows from the groove of the spool 21 of the lock-up shift valve 20 through the oil passage 134 to the cooler oil passage 132, then passes through the oil cooler 11 to be cooled, and is returned to the oil sump 1 through the oil passage 135. It will be done. In addition, the cooler oil passage 132 and the cooler 11 are protected by the cooler relief valve 1.
0 is connected to the cooler oil passage 132.

Next, consider a case where the lock-up clutch is in a semi-engaged state. In this state, the engagement capacity of the lock-up clutch is controlled in accordance with increases 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 since each position is set as shown in equation (3) above. When the spool 21 is moved to the left, the direction of line pressure supply from the oil passage 107 is switched to the oil passage 133, and the oil passage 133
However, line pressure is supplied to the inside of the torque converter 5, and the internal pressure of the torque converter 5 increases. As a result, the clutch plate 6b of the lock-up clutch 6 is placed on the engagement side (
In other words, it is pushed by the side that contacts the side surface of the case 5d),
Back pressure is generated within the release side back pressure chamber 6a.

The internal pressure of the torque converter acts in the direction of engaging the clutch plate 6b with the case 5d, and the back pressure acts in the direction of releasing it, but the release side back pressure chamber 6a where this back pressure is generated is filled with oil. It is connected to the lock-up control valve 30 via the passage 108, the groove of the spool 21 of the lock-up shift valve 20, and the oil passage 115,
The spool 31 of the control valve 30 is pushed leftward by the back pressure of the torque converter 65.

Note that since the oil passage 110 also communicates with the oil passage 116, the oil pressure acting on the right end of the lock-up timing valve 40 disappears, but the spool 41 of this valve 40 has already been moved to the right. It will be retained as is.

On the other hand, when the second solenoid valve 8 is subjected to duty ratio control, the oil pressure in the oil passages 112 and 113 is controlled according to this duty ratio, and becomes a duty ratio control oil pressure lower than the modulator pressure in the oil passage 106. This 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 its left end via the oil passage 112, but this control hydraulic pressure is lowered in response to an increase in the on-duty signal, and the spool 31 receives the right The pushing force in this direction varies depending on the duty ratio. This spool 31 is further pushed to the right by receiving internal pressure of the torque converter through oil passages 117 and 118 at its left end. For this reason,
The torque converter back pressure and the biasing force of the spring 32 acting on the right end, and the duty ratio control hydraulic pressure and torque converter internal pressure acting on the left end act on the spool 31, and the torque converter back pressure is adjusted according to the duty ratio control hydraulic pressure. and change.

That is, the engagement capacity of the lock-up clutch 6 is controlled by controlling the torque converter back pressure by changing the duty ratio control oil pressure.

As described above, a lock-up control state is obtained, and in this state, the second solenoid valve 8
When the first solenoid valve 7 is turned off from a state where the on-duty signal of the solenoid valve 7 becomes 100% (ie, the second solenoid valve 8 is on), a complete lock-up state is created. First solenoid valve 7
When the lock-up timing valve 40 is turned off, modulator pressure acts on the right end of the lock-up 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 a completely left-moved position, and the release side back pressure chamber 6a of the torque converter 5 is opened via the oil passages 108 and 115. It is communicated with the drain, and the torque converter back pressure becomes zero. As a result, the lock-up clutch 6 becomes fully engaged.

As explained above, the first solenoid valve 7 is turned on/off.
The capacity of the lock-up clutch 6 can be controlled only by the off control and the duty ratio control of the second solenoid valve 8. Here, the specific operating conditions when this capacity control is performed are shown in Fig. 2. The following is an explanation based on the graph.

In FIG. 2, the vertical axis represents the throttle opening and the horizontal axis represents the vehicle speed, and the area on both axes is divided into two by the lock-up-on operation line m (solid line).

The area to the left of this on-operation line m is an off area A, and when the driving state determined by the throttle opening and vehicle speed is within this off area A, the lock-up clutch 6 is controlled to be off. When the operating state moves from the OFF region A to the lockup region on the right side of the ON operation line m, engagement control of the lockup 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 driving state shifts to the lock-up region, the lock-up-off operation line n is provided. Lock-up clutch 6 when crossing
is turned off and moves to off area A.

The above lock-up area is further indicated by the dashed line 5 in the figure.
It is divided into five parts by book lines a to e, thereby forming a feedback area B, a control area C2, a first semi-tight area D, a second semi-tight area E, and a tight area F. Note that a deceleration lock-up region G is formed as a region where the throttle opening is approximately zero and the vehicle speed is equal to or higher than a predetermined vehicle speed (approximately 25 km/H).

The capacity of the lock-up clutch 6 is controlled according to the area formed as shown below, and the outline of the control will first be explained with reference to the flowchart of FIG. 3.

In this control, first, in step S1, a lock-up-off time is determined. This determination is made to turn off the lock-up clutch for a certain period of time when the gear is changed manually, that is, by manual operation of the shift lever, switching operation of the normal power mode changeover switch, etc. Next, the process proceeds to step S2, where the lock-up clutch is determined to be turned off when automatic gear shifting is performed. Here, when an automatic gear shift is performed, whether it is an upshift or a downshift, the degree of throttle opening, etc. are detected, and based on these, it is determined whether or not to perform lock-up.After this, the process proceeds to step S3. Proceed to determine whether it is necessary to turn off lock-up when the torque converter oil temperature is very low or very high, and determine that it is necessary to turn off lock-up in any of the above steps. If so, step S
Proceed to step 8 and the lock-up clutch is turned off.

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

If it is determined that the vehicle is not in a deceleration state, in step S6 it is determined in which region the operating state is on the map shown in FIG. 2, and the first and second
The operation of solenoid valve 7.8 is controlled (step S7).

Next, in the following, the control in step S7 described above is performed in the fourth step.
In the control described in detail using the flowchart in the figure, in steps 810 to 30, it is determined in which region the operating state is based on the lock-up zone code KZ. This zone code KZ is a number assigned to each region at the time of determination in step S6 in FIG. KZ=2 in region B and control region C, KZ=3 in the first semitight region, KZ=4 in the second semitight region E, and KZ=5 in tight region F. However, the process proceeds to step S6 only when the operating state is in the lock-up region, and this is the case when KZ=2°3.4 or 5.

First, in step S10, if it is determined that KZ=2, the operating state is within the feedback region B or control region C, and in this case, the process proceeds to step Sll. A determination is made as to whether a predetermined delay time LD2 has elapsed since the transition from the off area to areas B and C. This is to cause the lock-up operation to occur after a certain time delay when the operating state shifts from the OFF region A to the lock-up region. Therefore, when the value of the delay timer LDT is delayed, rr: Ir=0
Until the value becomes larger than 2, the current flow is ended as it is.

If LDT≧LD2, the next step 313
The learned value Dos calculated and stored in step 512 is stored as the off-duty ratio DOM, and a feedback component for duty ratio control of the second solenoid valve 8 is determined (step 813). Next, in step S14, Zon control is performed to slow down sudden changes in the duty ratio due to region transitions and to prevent shocks due to sudden changes in the duty ratio. Furthermore, in controlling the feedback area B or the control area C, it is necessary to turn on the first solenoid valve 7 as described above, so in step S15, a command to turn on the first solenoid valve 7 is issued,
Finish this flow.

Now, before proceeding to the steps below, step 31, 3
The control for determining the feedback component for duty ratio control of the second solenoid valve 8 in step 6 will be explained below. In this control, as shown in FIG. 5, first, the judgments shown in steps 351 to 55 are performed. In S51, it is determined whether or not the feedback prohibition flag Fep is set to 1. If it is set to 1, the process advances to step S57.

In step S52, it is determined whether the throttle opening degree TH is larger than the cruise judgment throttle opening degree THCR. This cruise judgment throttle opening THC
R is the same as the throttle opening indicated by the chain line a that separates the feedback region B and the control region C in FIG. 2, and TH>THCR means that the operating state is within the control region C. , in this case, the process advances to step S57.

In step S53, it is determined whether or not the brake is being operated, and if the brake is being operated, the process proceeds to step S57.

In step S54, the temperature range code NT is 2.
A determination is made as to whether or not NT≠2, the process advances to step S57. This temperature range code NT is set to five values from 0 to 4 depending on the torque converter oil temperature, and indicates extremely low temperature, low temperature, normal temperature, high temperature, and extremely high temperature, respectively. Here, in the case of extremely low temperatures and extremely high temperatures (N
In the case of T=0 and 4), lockup is turned off in step S3 of FIG.
In the case of 2 (in the case of normal temperature), the process advances to step S55, and N
If T=1 or 3 (low temperature or high temperature), the process advances 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 the engine cooling water temperature TW is lower than the 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, in step S57, the correction permission flag FOR is set to 0, and in step S58.5, the sampling counter value P is set to zero, and the speed ratio integral value is set to 0. Set Σe to zero. Note that when proceeding to step S57, as can be seen from the determination in step S52,
in the control area; in this case,
The off-duty value DOM of the second solenoid valve 8 is the latest learned value 1) o stored in step S12 in FIG.
It becomes s.

On the other hand, if the process proceeds to step S56, this is in the feedback region, and in this case, feedback control is performed using C-e control. This step S
The contents of the C-e control shown in 56 will be explained using FIGS. 6 to 11.

As shown in FIG. 6, this C-e control includes an average speed ratio calculation routine e□cat (step 561) that calculates the average value of the input/output rotational speed ratio e of the lock-up clutch for each average value calculation time TCR. The speed ratio e is set as the target speed ratio based on the difference between the average speed ratio eav calculated here and the target speed ratio range (the range from eL to eH, which corresponds to the predetermined reference range in the claims). The ellV correction routine (step 562) corrects the duty ratio so that the speed ratio e falls within the range TeH for a predetermined period of time.
An eH correction routine (step 863) that corrects the duty ratio in real time so as to return it to within the target speed ratio range when the speed ratio continues to be exceeded, and the latest value of the duty ratio obtained in the above routine is required. Update accordingly and store this as the learned value I)os I)os
update routine (step 564).

Before explaining each of the above routines (steps 361 to 64), an outline of these controls will be explained using FIG. 7 showing changes in the speed ratio e due to these controls.

In FIG. 7, the vertical axis shows the speed ratio e, and the horizontal axis shows time, and the solid line in this graph shows the actual change in the speed ratio e. The target speed ratio range is between the lower limit speed ratio eL (e.g., eL=0.95>) and the upper limit speed ratio en (e.g., eH-〇, 98), each indicated by a dashed line, and the average value is calculated. Average speed ratio e ay calculated for each time TCR
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 (control in step S62).

During this control, if the actual speed ratio e exceeds the upper limit speed ratio e11, the speed ratio e will be 1.0 (complete lock-up).
becomes very close to , and tends to reach 1.0. When the speed ratio reaches 1.0 and a complete lock-up state occurs, engine vibrations may be transmitted to the drive system and vehicle body and cause muffled noise etc. if the driving state is within feedback region B. It is desirable to reliably prevent lock-up, and this licking is carried out for a specified time T.

■ During the above period, if the speed ratio e exceeds the upper limit value eo, instead of controlling using the average speed ratio eav as described above,
Based on the speed ratio e at that time, the speed ratio e
Duty ratio setting control (control in step 363) is performed to maintain the value within the target range.

In the above control, the duty ratio corrected based on the average speed ratios e and v is updated and stored as a learned value DO9 each time the value becomes appropriate (step 564).

The flowchart in FIG. 8 shows the contents of the routine of step S61. Here, first, it is determined whether the sampling timer T'sp has become zero (step 570), and when this becomes zero, the process proceeds to step S71, and the value of the sampling counter P has reached the sampling number a. Make a determination as to whether or not. sampling timer T
'sp is the periodic interval at which the speed ratio is detected, and the average speed ratios e and v are calculated by performing detection a number of sampling times in this period and finding the average of these.Average value calculation 1 Time TCR=TgPXa.

Therefore, until the value of the sampling counter P reaches a, the step S is performed every cycle of the sampling timer TsP.
Proceeding to step 72, the value of the counter P is incremented by 1, and the current detected speed ratio e(P) is added to the previous speed ratio integral value Σe to obtain the current speed ratio integral value Σe. This allows P-0 to P
- (a-1) (during TCR), 8 speed ratios e
The sum of (P), that is, the integral value Σe of the speed ratio e during the average value calculation time TCR is determined by dividing it into each average value calculation time TCR.

Then, at the time when P=a, step S71
The process then proceeds to step S74, where the speed ratio integral value Σe obtained as described above is divided by the number of sampling times a to calculate the average speed ratio eav at the current average value calculation time TCR. After this, in order to calculate the average speed ratio at the next average value calculation time TCR, the values of the sampling counter P and the speed ratio integral value Σe are set to zero, and further, in response to the calculation of the average speed ratio ellV, , set 1 to the correction timing flag FOE and the correction permission flag FOR (
Steps 375-78).

Next, the e1v correction routine (step 562) for correcting the duty ratio using the average speed ratio eaV obtained as described above will be explained using the flowchart of FIG.

In this flow, it is not judged whether the correction permission flag FOR is 1 or not (step 580), and when it is 0, the learning value update timer T Dos is set to zero (step 580).
Step 581), furthermore, the correction timing flag FC
No judgment is made as to whether e is 1 or not (step 582), and if it is zero, this flow is immediately ended.

When this is 1, it is determined in step 383 whether the average speed ratio eav is larger than the upper limit speed ratio e shown in FIG. 7, and if e av>e□, the process advances to step S88. In step S88, a weak correction value Xll is obtained by multiplying the difference between the average speed ratio eaV and the upper limit speed ratio eH by a predetermined coefficient β, and this weak correction value Correction value
The new off-duty ratio obtained by adding n is stored as the control duty ratio during the current average value calculation time TcR (step 589). As a result, the engagement capacity of the lock-up clutch is reduced to the above-mentioned weak duty ratio. The speed ratio that has become larger than the upper limit speed ratio eH is reduced by the amount corresponding to the correction value
s is set to zero (step 590), and the correction timing flag Fee is set to zero (step 592).
The correction determination time TeH is set to the initial value for the next flow (step 393), and the current flow ends.

On the other hand, if it is determined in step 383 that eaV≦eo, the process proceeds to step S84, and e, , < e
If e av < e L, the process proceeds to step S85. In step S85, the difference between the lower limit speed ratio eL and the average speed ratio eaV is multiplied by a predetermined coefficient α to calculate the The correction value XL is calculated, and the new off-duty ratio obtained by subtracting this strong correction value XL from the previous off-duty ratio for controlling the operation of the second solenoid valve 8 is calculated during the current average value calculation time TCR. It is stored as a control duty ratio (step 886). As a result, the engagement capacity of the lock-up clutch is increased by an amount corresponding to the strong correction value XL, and the speed ratio that has become smaller than the upper limit speed ratio eL is increased to bring it within the target speed ratio range. Let someone correct it. Next, the learned value update timer TDos is set to zero (step 587),
Fce and TeH settings are made (step S92
,93), the current flow ends.

In step S84, if it is determined that e av > e L, the average speed ratio eAv is within the target speed ratio range, so the process proceeds to step S91, and the learned value update timer T
The value of Dos is increased by 1, Fce and TeH are set (step 392.93, and the current flow ends.

Next, the eH correction routine shown in step 363 of FIG. 6 will be explained using the flowchart of FIG. 10.

In this control as well, it is first determined whether the correction permission flag FOR is 1 (step 5101), and if this is zero, the process proceeds to step 5110 and the eH correction judgment time Tel
Set to the initial value. If FOR=1, the actual speed ratio e at that time is set to the upper limit speed ratio e in step 5102.
It is determined whether or not it is greater than H. If e≦eH, the process advances to step 5110 and the e14 correction determination times T and H are set to initial values.

At the time of even, it is determined whether or not e, the correction determination time Te11 has become zero (has it increased so much). The fact that this goes up means that the state of e ) e H is e
This means that the H correction determination time (predetermined time) T has continued for 8 or more, and in this case, the control from step 8104 onwards is performed. Note that if the above-mentioned judgment time 'fall' has not increased, the current flow ends as it is.

In step 5104, in order to reduce the engagement capacity of the lock-up clutch and reduce the speed ratio e to below the upper limit value eH, a predetermined correction 41 Do is added to the off-duty ratio of the second solenoid valve 8 to correct this. do.

Thereafter, in steps 5105 and 106, the sampling counter P and the speed ratio integral value Σe are set to zero, and in step 5107, the sampling timer T'sp is set. Furthermore, in step 5108, the Zon control permission flag FZ is set to O, and as for eH correction, Zon control is not performed and the correction is performed immediately, and in step 5109, the learning value update timer TD os is set to zero. do.

After this, in step 5110, eH correction determination time T
Set eH to the initial value and end the current flow.

The I) OS update routine, which is step S64 in FIG. 6, is shown in the flowchart in FIG. Here, Zo
Determine whether n permission flag FZ is 1 (step 5121
) and the learning value update timer TDos is the update judgment time DD.
Determine whether or not the OS has reached or exceeded (step S122)
is carried out, Zone control is not executed, and the speed ratio e
is within the target speed ratio range for the update determination time DDos or longer, in step 8123, the off-duty ratio at this time is stored as a learned value 1)os.

For this reason, the off-duty ratio stored in step S1.2 of FIG. M is the latest learned value Do5, which is the most appropriate value at that time to maintain the speed ratio e within the target speed ratio range.

In the above, control has been explained when the operating state is in the feedback region B or control region C, but the control when the operating state is in the first semi-tight region D, second semi-tight region E, or tight region (on region) F The control will be explained by returning to the fourth point.

When the operating state is in the feedback region B or control region C, the zone code KZ=2, and control is performed by proceeding from step S10 to step S11. However, if 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, and in this case, the process advances to step S21, where the delay timer LDT
Depending on the value of
After waiting for time LD3, the process advances to step S22. In step S22, the value obtained by subtracting the constant value DI from the latest learned value 1) os is set as the off-duty value. Remember as M. Here, the learned value I) os is also a value indicating the off-duty ratio, and reducing the constant value means increasing the on-duty ratio, so that in the first semi-tight region, the learned value . An off-duty value DOM is set to a value that increases the engagement capacity of the lock-up clutch by a certain amount from the engagement capacity of the lock-up clutch based on S.

The engagement capacity of the lock-up clutch in the first semi-tight region is set to such a capacity that the lock-up clutch is fully engaged during normal driving, but slips during acceleration driving. be. For this reason, the capacity is increased by a certain amount as described above, but as mentioned above, the learning value is increased. 5 is the latest value of the duty ratio for maintaining the speed ratio e within a predetermined reference range when it is in the feedback region, and this learned value I
) By increasing the capacity of os by a certain amount, it is possible to easily and reliably set the optimum engagement capacity at that time.

Next, if the duty ratio set in this way is used immediately, Zon control is performed in step 323 to prevent the duty ratio from changing suddenly and causing a shock. A smoothing correction will be added. Also, in this area, the first
Since the solenoid valve 7 needs to be turned on, a command for this purpose is output in step S24, and the current flow ends.

Further, if it is determined in step S30 that KZ=4, the operating state is within the second semi-tight region E, and in this case, the process advances to step S31, and the operation state is determined to be within this region according to the value of the delay timer LDT. After waiting for a predetermined delay time LD4 after the transition, the process proceeds to step S32.
In step S32, the off-duty value DoM is set to zero, that is, the on-duty value is set to 100.
%), and in step 833.34, Zon control similar to the above and an ON command to the first solenoid valve 7 are output, and the current flow ends.

Furthermore, if it is determined in step S30 that KZ≠4, since KZ=5, the operating state is within the tight region (lock-a-ra 1 on region) F, and in this case, the process advances to step S40, where the delay timer is After waiting a predetermined delay time LD5 after moving into this range according to the value of LDT, the process proceeds to step S41. In step S41, the value of the off-duty value DOM is set to zero, and further in step S42, the above-mentioned The same ZOn control is performed.

Next, the process proceeds to step 343, where it is determined whether or not the Zon execution flag FZ is 1.
1 is set while the duty ratio is being corrected by the above Zon control, and this flag FZ is set to O.
After waiting for the above correction to be completed, the process proceeds to step S44, and the second solenoid valve 8
Outputs a command to turn on.

After that, in step S45, it is determined whether or not the solenoid on timer Tz1 has become zero, and until this becomes zero, the first solenoid valve 7 is kept on (step 846), and the above-mentioned timer is Tzl
When becomes zero, a command to turn off the first solenoid valve 7 is output (step 547). 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 made after waiting for a certain period of time.

The control explained above determines the duty ratio of the second solenoid valve 8. Since this duty ratio is controlled so that the speed ratio e falls within a predetermined reference range, if the engine torque component fluctuates, the duty ratio of the second solenoid valve 8 is determined. In response to this variation, the lock-up engagement capacity is controlled to vary so that the speed ratio e falls within the above range. Therefore, the duty ratio determined as described above is a value that includes a component corresponding to the engine torque, and for example, the same speed ratio is used when driving on a slope and when driving on a flat road. The duty ratio required to obtain is different.

For this reason, in this 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 lock-up engagement capacity is estimated and set based on the

This will be explained using FIG. 12. As an example,
Consider setting the duty ratio during normal driving at 50km/H. In this case, if the engine torque is 4 kg-m and the learned value of the feedback component is 20% (on side), the engine torque component is 20% as seen from the figure, and the feedback component is , 50X (
20/100)=10%. Therefore, the on-duty ratio of the second solenoid valve 8 in this case is 30%, which is the sum of both components. Note that when the operating state is in the first semi-tight region, a value obtained by adding a constant value to the above-mentioned learned value is used as the feedback component.

Here, the control content of the solenoid valve for each area is
Organize based on the table in Figure 3. 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 OFF.
is also OFF, that is, 0% on duty.

In the case of the feedback region, the first solenoid valve 7 is switched ON, and the second solenoid valve 8 is activated to control 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. It is controlled by the duty ratio set by . In the control region, the latest learned value stored in the feedback control becomes the feedback component, and control is performed using a duty ratio set by the sum of this and an engine torque component corresponding to the engine torque. In the first semi-tight region, control is performed using a duty ratio set by the phase of the engine torque component and a feedback component in which a constant value for increasing the engagement capacity is added to the latest learning value. Second
In the semi-tight region, the first solenoid valve 7 is ON, the feedback component of the second solenoid valve 8 is ON, that is, 100%, the engine torque component uses a value corresponding to the engine torque, and the duty ratio is determined by the sum of both components. is set, and the timing valve 40 is set to O.
It is left as FF. In the tight region, the first solenoid valve 7 is turned off and the timing valve 40 is turned on.

In addition, in the above embodiment, the second solenoid valve 8
An example was shown in which the speed ratio of the input and output rotation speeds of the lock-up clutch was used to determine the control duty ratio of the
Instead of this speed ratio, the difference between the input and output rotation speeds may be used for determination. Further, instead of the solenoid valve whose duty ratio is controlled in this way, a proportional electromagnetic valve may be used, and in this case, current value control is performed instead of duty ratio control.

Further, in the above embodiment, a torque converter is used as the fluid power transmission device, but other types of fluid power transmission mechanisms, such as fluid couplings, may be used.

As described in detail in the invention, according to the control method of the present invention, the engagement capacity of the lock-up clutch is feedback-controlled so that a constant slip always occurs in the lock-up clutch in the feedback region. The increase in engagement capacity required to fully engage the lock-up clutch can be easily predicted, and therefore the latest engagement capacity control value in the feedback area can be used to increase the engagement capacity in the semi-tight area. The control value of the total capacity can be accurately predicted, and good control can be performed even in a semi-tight region.

[Brief Description of the Drawings] Figure 1 is a hydraulic circuit diagram around a torque converter with a lock-up clutch whose engagement capacity is controlled by the method of the present invention. Figure 2 is the relationship between throttle opening and vehicle speed. 3 to 6 and 8 to 11 are flowcharts showing the operation control details of the solenoid valve that controls the operation of the lock-up clutch. Figure 12 is a graph showing the relationship between the solenoid valve duty ratio and engine torque, and Figure 13 is a table showing the control details of the solenoid valve in each region. It is. 1...Oil sump 2...Hydraulic pump 3...
・Regulator valve 5...Torque converter 6・
...Lock-up clutch 7.8...Solenoid valve 11...Oil cooler 20...Lock-up shift valve

Claims (1)

[Claims] 1) Control of the engagement capacity of a direct coupling mechanism that is disposed between the input side and the output side of a fluid power transmission device and mechanically engages and disengages the input side and the output side. The method is such that an off region in which engagement by the direct coupling mechanism is disengaged and a parameter representing a slip amount between the input side and the output side are set to values within a predetermined reference range depending on the operating state. a feedback region for feedback controlling the engagement capacity; a semi-tight region for controlling the engagement capacity so that the direct coupling mechanism is engaged during normal driving but slips during acceleration; and a semi-tight region for controlling the engagement capacity so that the direct coupling mechanism is fully engaged. In the method, the engagement capacity is controlled separately in the on-region, in which the engagement capacity is controlled in the feedback area, and the engagement capacity is controlled when the parameter reaches a value within the predetermined reference range. A direct coupling mechanism control method for a fluid power transmission device, characterized in that a control value of an engagement capacity of the direct coupling mechanism in the semi-tight region is determined based on the value.