JPH0246366A - Directly coupling mechanism control method for fluid type power transmission device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A. Object of the Invention (Field of Industrial Application) The present invention provides a mechanically disconnectable direct connection between an input side and an 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 instead of just turning the lock-up clutch on and off, it is also in a semi-engaged state as an intermediate state between on and off. Lock-up control is also often performed at the same time.

Such control is performed in a predetermined operating range at relatively low speeds, and instead of completely directly connecting the torque converter, for example, the torque converter is controlled so that the lock-up clutch is slipped in response to the peak value of torque fluctuation. Input/output rotation speed ratio e1 or slip ratio (1-e)
is calculated, and in the above predetermined operating range, the rotation speed ratio e is 1.
Alternatively, these actual measured values are fed back so that the slip ratio does not become 0. An example of such a control method is disclosed in Japanese Patent Application Laid-Open No. 81-2881365.

This kind of feedback control that puts the lock-up clutch in a semi-engaged state is performed in low vehicle speed ranges where the engine speed is low and full lock-up tends to generate surge vibrations, crashing noises, rattling sounds, etc., and suppresses the amount of slip. This suppresses a decrease in fuel efficiency, and also generates a certain amount of slip to suppress the generation of the above-mentioned surge vibrations, crashing noises, etc.

In the above, we have explained the control of the lock-up clutch when the vehicle is running while receiving driving force from the engine (hereinafter referred to as the running state). It is also important to control the lock-up clutch when the pedal is released and the vehicle is running while decelerating due to engine braking action (hereinafter, this state is referred to as a deceleration state).

During deceleration, it is desirable to engage the lock-up clutch in order to obtain sufficient engine braking force, but if it is fully engaged, surge vibration,
There is a problem in that it may lead to the occurrence of a crashing sound, a rattling sound, etc.

For this reason, it has been proposed to perform feedback control of the engagement capacity of the lock-up clutch so that it is in a semi-engaged state, thereby preventing the above problem from occurring and also making it possible to obtain engine braking force. .

(Problem to be Solved by the Invention) In this case, if the set value of the engagement capacity, which is the initial value of the feedback control, is too large, there may be problems such as generation of shock or the lock-up clutch may become completely engaged. On the other hand, if the initial value of the engagement capacity is too small,
Not only is the initial engine braking force too small;
There is a problem in that after the engine rotation once decreases, it increases again in response to an increase in the engagement force due to feedback control, resulting in an unnatural feeling of deceleration driving.

As can be seen from this, when performing feedback control to shift to a deceleration state and bring the lock-up clutch into a semi-engaged state, it is important to set the initial value of this feedback control to an appropriate value. However, since the capacity characteristics of lock-up clutches vary depending on individual differences, changes in oil temperature, etc., there is a problem in that it is very difficult to predict an appropriate initial value at each point in time.

For this reason, the present invention provides good deceleration performance by setting an appropriate initial value without being affected by variations in engagement capacity due to individual differences, changes in oil temperature, etc. when transitioning to a deceleration state. The purpose is to provide a control method that can obtain the following.

Configuration of the invention (means for solving the problem) As a means for achieving the above object, in the control side method of the present invention, when the operating state is in a predetermined region (for example, a feedback region), the direct coupling mechanism In order to ensure that the parameter representing the amount of slip between the input side and output side of the lock-up clutch (lock-up clutch) is within a predetermined standard range, the engagement capacity is adjusted to a predetermined value using a foot control (as described above during this feedback control). The control value of the engagement capacity when the value falls within the reference range is stored, and when the vehicle shifts to a deceleration state, the engagement capacity of the direct coupling mechanism is adjusted based on the memorized control value. An initial value of the control value is determined, and this initial value is used to perform feedback control of the engagement capacity so as to maintain the above-mentioned parameter within a target range.

(Function) In the case of such a control method, the operating state is within a predetermined range (
feedback region), and when feedback control is performed, feedback control is performed so that a constant slip always occurs in the lock-up clutch (direct coupling mechanism), so the engagement capacity characteristics of each individual (each lock-up clutch) It is also possible to grasp the accurate relationship between the control value of the engagement capacity depending on the oil temperature, etc. at that time, and the engagement capacity (or the amount of slits or protrusions). Therefore, if the initial value of the feedback control when transitioning to the deceleration state is set based on the control value grasped in this way,
It becomes possible to set an appropriate engagement capacity.

(Example) Preferred examples of the present invention will be described below 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 lock-up clutch 6 that can directly connect the impeller 5a and the turbine 5b, and the operation of the lock-up clutch 6 is controlled by the on/off operation of the first solenoid valve 7 and the duty ratio of the second solenoid valve 8. a lock-up shift valve 20 that is operated in accordance with the operation;
This is achieved by 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 sucked from an oil sample 1 through an oil path 101 and discharged from a hydraulic pump 2 to an oil path 102 is brought to 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 path 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 P 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, oil passage 7b communicating with oil passage 106 via orifice 7a+8a, respectively;
8b is blocked by the spool of the solenoid valve 7.8, and the oil passages 110, 111, 112, and 113 are
Modulator pressure PM from oil passage 106 acts. Therefore, the modulator pressure P is applied to both ends of the lock-up shift valve 20 via the oil passages 110, 113 and the oil passage 111.
, the spool 21 of this valve 20 is 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 which communicates with the oil passage 110. is A2, and the pressure receiving area of the spool 21 that receives the oil pressure from the third oil chamber 25c communicating with the oil passage 111 is A3, then AI=A2...(1) Formula A
3XPM < (AI +A2) XPM +FS・
...Formula 0 A3 For this reason, the first to third oil chambers 25a to 2
When the modulator pressure PH acts on all 5c, the spool 21 is moved to the right by the spring force Fs.

Further, the modulator pressure PH acts on the left end of the lock-up control valve 30 through the oil passage 112, and the spool 31 of this valve 30 is moved to the right, causing the oil passages 113, 1
14 and oil passages 110 and 116, modulator pressure acts on both ends of the lock-up timing valve 40,
The spool 41 of the timing valve 40 is the spring 42
It moves to the right due to the bias.

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 the 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 8b connected to the turbine 5b is separated from the case 5d connected to the impeller 5a, and the lock-up clutch 6 is released. Turns off.

Note that 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 passed through the lock-up shift valve. The oil flows from the groove of the spool 21 of No. 20 to the cooler oil passage 132 via the oil passage 134, then passes through the oil cooler 11, is cooled, and is returned to the oil sump 1 via the oil passage 135. In addition, in order to protect the cooler oil passage 132 and the cooler 11, a cooler relief valve 1 is provided.
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 is moved to the left because multiple values are set as in equation (3) above. When the spool 21 is moved to the left, the direction of supply of line pressure from the oil passage 107 is switched to the oil passage 133, and the line pressure is supplied from the oil passage 133 to the inside of the torque converter 5, causing the internal pressure of the torque converter 5 to becomes higher. As a result, the clutch play 8b of the lock-up clutch 6 is pushed toward the engagement side (that is, the side that contacts the side surface of the case 5d), and back pressure is generated in 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.

In addition, since the oil passage 110 also communicates with the oil passage 116,
Although the hydraulic pressure acting on the right end of the lock-up timing valve 40 disappears, the spool 41 of this valve 40 has already been moved to the right and is held as it 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 oil pressure is oil pressure that decreases as the ratio of the on-duty signal increases, and increases as the vehicle speed increases, for example.

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, modulated pressure acts on the right end of the lock-up timing valve 40 from the oil passages 110 and 118. 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 6 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 dotted chain line in the figure.
It is divided into five by lines a-e, thereby forming a feedback area B1 a control area C1 a first semi-tight area D1 a second semi-tight area E and a tight area F. Further, a deceleration lock-up region G is formed as a region where the throttle opening becomes almost zero and the vehicle speed is equal to or higher than a predetermined vehicle speed (approximately 25 mm/H).

The capacity of the lock-up clutch 6 is controlled according to the area formed as described above, and the outline of the control content will first be explained using the flowchart of FIG. 3.

In this control, first, in step S1, a lock-up-off time is determined. This determination is to turn off the slip-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 it is determined whether the lock-up clutch is 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. Then, it is determined whether it is necessary to turn off the lockup when the torque converter oil temperature is extremely low or extremely high. If it is determined that lockup needs to be turned off in any of the steps above, step S
Proceed to step 9 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. When the vehicle is in a deceleration state, first, in step S7, the control off-duty ratio initial value Di is set. Off-duty ratio learning value. A value obtained by subtracting a constant value α from S is read. These duty ratios are all off-duty ratios, and therefore have learning values. Subtracting the constant value α from 8 means increasing the on-duty ratio, and thereby the initial value of the engagement capacity of the lock-up clutch 6 is set larger than the capacity based on the learned value. In addition, this learning value. 8 is a value stored in the control in the feedback area, the explanation of which will be given later. Next, the process proceeds to step S8, where deceleration lock-up control is performed, and when the vehicle speed is reduced to a predetermined vehicle speed or less by this control, the process proceeds to step S9, where the lock-up clutch is turned off.

If it is determined that the vehicle is not in a deceleration state, in step S5 it is determined in which region the operating state is on the map shown in FIG.
The operation of solenoid valve 7.8 is controlled (step SS).

Next, before explaining the deceleration lock-up control in step S8, the control in step S6 will first be explained in detail using the flowchart of FIG.

In this control, in steps 810 to 30,
The operating state is determined from the lock-up zone code KZ. This zone code KZ is a number assigned according to each region at the time of determination in step S5 in FIG. Region B and control region C have KZ=2, the first semitight region has KZ=3, the second semitight region E has KZ=4,
The tight region F has KZ=5. However, the process proceeds to step S5 only when the operating state is in the lock-up region, and when KZ=2°3.4 or 5.

First, in step 810, if it is determined that KZ=2, the operating state is within feedback region B or control region C, and in this case, the process proceeds to step 811. In step 811, it is determined whether or not a predetermined delay time LD2 has elapsed since the operating state shifted from the off range to these ranges 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, the value of the delay timer LDT is longer than the delay time LD2. Until it becomes larger, this flow will end as it is.

When LDT≧LD2, the next step S13
The learning value Dos calculated and stored in is compared with the off duty. M is stored as step 512), and a feedback component for duty ratio control of the second solenoid valve 8 is determined (step 513). Next, in step 814, Zon control is performed to slow down sudden changes in the duty ratio due to region transitions and to prevent blockages 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 815, a command to turn on the first solenoid valve 7 is issued,
Finish this flow.

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

In this control, as shown in FIG.
The judgments shown in 51 to 55 are made. In step 851, 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 857.

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 857.

In step 854, the temperature range code NT is set to 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=O and 4), the lockup is turned off in step S3 of FIG.
In the case of 2 (normal temperature), proceed to step 855 and N
If T=1 or 3 (low temperature or high temperature), the process advances to step S57.

In step 855, 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 or equal to this permission temperature TW, the process proceeds to step 857, and if it is higher than this, the process proceeds to step S58. move on.

If the process proceeds from the above judgment step to step 857, the correction permission flag F is set in step 857. O is set in R, and further, in step S58.59, the sampling counter value P is set to zero, and the speed ratio integral value Σe is set 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,
Off-duty value of second solenoid valve 8. M is the latest learning value stored in step 812 of FIG. S
becomes.

On the other hand, if the process proceeds to step 85B, this is in the feedback region, and in this case, feedback control is performed using C-e control. This step 8
The contents of the C-e control shown in 5B will be explained using FIGS. 6 to 11.

As shown in FIG. 6, this C-e control is an average speed ratio calculation routine e av c a l (step 561), the average speed ratio ellV calculated here and the target speed ratio range (e t
"e) Correct the duty ratio so that the speed ratio e falls within the target speed ratio range based on the difference between
° correction routine (step 562); and an eH correction routine that corrects the duty ratio in real time so as to return it to within the target speed ratio range when the speed ratio e exceeds the upper limit value eH for a predetermined period of time Ta8 or more. (Step 5
63), and update the latest value of the duty ratio obtained in the above routine as necessary, and use this as the learning value. I remember it as S. 8 update routine (step 564).

Before explaining each of the above routines (steps 861 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 (for example, eL = 3.95) and the upper limit speed ratio eH (for example, eH = 0.98) indicated by the dashed line, and the average value is calculated. Based on the difference between the average speed ratio eav (the value indicated by the thick line in the figure) calculated for each time TCR and the target speed ratio range value, the speed ratio e is controlled to fall within this target speed ratio range. (control of step 882).

During this control, if the actual speed ratio e exceeds the upper limit speed ratio e, the speed ratio e becomes very close to 1.0 (complete lock-up) and tends to reach 1.0. speed ratio 1
．． 0 and enters a complete lock-up state, engine vibrations may be transmitted to the drive system and vehicle body when the driving condition is within feedback region B, causing muffled noise, etc., so make sure to ensure complete lock-up. Therefore, if the speed ratio e exceeds the upper limit value eH for a predetermined time period of 11 or more, the control is not based on the average speed ratio eav as described above, but is controlled based on the speed ratio e at that time. Based on this, duty ratio setting control (
The control in step 5f33) is performed.

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

The flowchart in FIG. 8 shows the routine of step 881. Here, first, it is determined whether the sampling timer Tsp has become zero (step 570), and when this becomes zero, the process proceeds to step S71, and the value of the sampling counter P reaches the sampling number a.
It is determined whether the Sampling timer T'
sp is a periodic interval at which the speed ratio is detected, and the average speed ratio eav is calculated by performing sampling a number of times in this period and finding the average of these detections, and the average value calculation time T. R=T'8Pxa.

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. As a result, from P=0 to P=(a-1) (during TCR), the sum of a number of speed ratios e (P), that is, the integral of the speed ratio e during the average value calculation time TcR The value Σe is the average value calculation time T. R
It is calculated separately for each item.

Then, at the time when P=a, step 871
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 obtain the current average value calculation time T. Calculate the average speed ratio e0 at 3. After this, the next average value calculation time T. In order to calculate the average speed ratio at R, the sampling counter P and the speed ratio integral value Σe are set to zero, and the average speed ratio e
In response to the calculation of lkV, the correction timing flag Fce and the correction permission flag FOR are set to 1 (steps 875 to 78).

Next, the eav 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, the correction permission flag F. It is not judged whether 3 is 1 or not (step 580), and when it is O, the learning value update timer TDo8 is set to zero (step 581). Furthermore, a correction timing flag F. No judgment is made as to whether or not 6 is 1 (step 582), and if this is 0, the flow is immediately ended.

When this is 1, it is determined in step S83 whether the average speed ratio eaV is larger than the upper limit speed ratio e shown in FIG. 7, and if e&v>e, step 8
Proceed to 88. In step S88, the average speed ratio e
, v and the upper limit speed ratio eH is multiplied by a predetermined coefficient β to obtain a weak correction value XH, and this weak correction value XH is added to the previous off-duty ratio for controlling the operation of the second solenoid valve 8. The new off-duty ratio is calculated using the current average value calculation time T. It is stored as a control duty ratio between R (step 589). Additionally, the engagement capacity of the lock-up clutch will be reduced by the amount corresponding to the weak correction value Let someone inside fix it. Next, the learning value update timer TDos is set to zero (step 590), the correction timing flag Fee is set to zero (step 592), and the correction judgment judgment time TaH is set to the initial value for the next flow (step 593). ), this flow ends.

On the other hand, if it is determined in step 883 that 13av≦eo, the process proceeds to step 884, and eav<eL
A determination is made as to whether or not elv is equal to eL, and the process advances to step S85. In step S85, a strong correction value XL is obtained by multiplying the difference between the lower limit speed ratio eL and the average speed ratio eav by a predetermined coefficient α, and this strong correction value XL is calculated from the previous off-duty ratio for controlling the operation of the second solenoid valve 8. The new off-duty ratio obtained by subtracting the correction value Xt is
This average value calculation time T. It is stored as a control duty ratio between R (step 586). 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 upper limit speed ratio eL
The speed ratio that has become smaller is increased to correct it to within the target speed ratio range. Next, the learning value update timer T
Dos is set to zero (step 587), Fce, T, and H are set (steps S92 and 587).
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 Te1H are set (steps 892 and 593), and the current flow ends.

Next, the eH correction routine shown in step S63 in FIG. 6 will be explained using the flowchart in FIG. 10.

In this control as well, the correction permission flag F is first set. It is determined whether R is 1 or not (step 8101), and if it is zero, the process advances to step 5110 and eH correction determination time TaN
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.
A judgment is made as to whether or not it is larger than N. When e≦e, the process advances to step 5110 and the eII correction determination time TaH is set to the initial value.

When e>eH, it is determined whether eH correction judgment time Te1 (has become zero (up) )T, □ means that the process has continued for a period of time or more, and in this case, the control from step 5L04 onwards is performed.If the above-mentioned judgment time TaH has not increased, the current flow ends as it is.

In step 5104, a predetermined correction amount D)l is added to the off-duty ratio of the second solenoid valve 8 in order to reduce the engagement capacity of the lock-up clutch and reduce the speed ratio e to below the upper limit value eo. to correct. After that, in steps 5105 and 108, the sampling counter P and the speed ratio integral value Σe are set to zero, and in step 5107, the sampling timer T
Set BP. Further, in step 5108, the Zon control permission flag FZ is set to 0, and as for eIl correction, Zon control is not performed but correction is performed immediately, and in step 5109, the learning value update timer TDos is set to zero.

After that, in step 5110, el (correction determination time TaH is set to the initial value, and the current flow is ended.

This is step 8B4 in FIG. The 8 update routine is shown in the flowchart of FIG. Here, the Zone
Determining whether permission flag FZ is 1 (step 5121)
and learning value update timer TDos is update judgment time DDo
s or more (step 8122), ZOn control is not executed, and if the speed ratio e has been within the target speed ratio range for the update determination time DDos or more, In step 5123, the off-duty ratio at this time is stored as a learning value Dag.

Therefore, the off-duty ratio stored in step 812 of FIG. H is the latest learning value. 8, which is the most appropriate value at that time to maintain the speed ratio e within the target speed ratio range.

In the above, the control when the operating state is in the feedback region B or the control region C has been explained, but the control when the operating state is in the first semi-tight region D1 second semi-tight region E or tight region (on region) F other than this has been explained. This will be explained by returning to FIG.

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 811. 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 proceeds to step 821, where the delay timer LDT
Depending on the value of
After waiting for time LD3, the process advances to step S22. In step 822, the latest learning value is determined. From S to constant value D
The value obtained by subtracting 1 is the off-duty value. Remember as M. It's worth learning here. g 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 learning value is increased. The off-duty value is set to a value that increases the engagement capacity of the lock-up clutch by a certain amount from the engagement capacity based on S. , 4 are set.

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. 8 is the latest value of the duty ratio for maintaining the speed ratio e within a predetermined reference range when the speed ratio is in the feedback region, and is based on this learning value. By increasing the capacity of S 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, the change in duty ratio will be rapid and the system will fail.
In order to prevent this from occurring, Zon control is performed in step S23, and corrections are made to smooth changes in the duty ratio. 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 824, 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 proceeds to step 831, 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 advances to step 832.

In step S32, the off-duty value is set. The value of H should be set to zero, that is, the on-duty value should be set to 100.
%), and in steps S33 and S34, the same Zon control as above and an output of an ON command to the first solenoid valve 7 are performed, and the current flow ends.

Furthermore, if it is determined in step 830 that KZ≠4, since KZ=5, the operating state is within the tight region (lock-up region) F, and in this case, the process advances to step S40, and the delay timer is After a predetermined delay time LD5 has elapsed after moving into this range based on the value of LDT, the process advances to step S41. In step S41, the off-duty value is set. The value of M is set to zero, and in step S42, Z is set as above.

Perform n control.

Next, the process proceeds to step 843, where it is determined whether the zOn execution flag FZ is 1 or not. This Zon execution flag FZ is
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 845, it is determined whether or not the solenoid on timer T2□ has become zero, and until this becomes zero, the first solenoid valve 7 is kept on (step 546), and the above Timer TZI
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.

Next, a case will be described in which it is determined in step S4 of FIG. 3 that the vehicle is in a deceleration state and deceleration lock-up control is performed.

In this case, as in the case of the feedback region, feedback control is performed to maintain the speed ratio within the target range. Since the pedal is no longer depressed and the vehicle enters the deceleration state, there is a problem in that the engagement capacity becomes too large if the duty ratio before the shift to the deceleration state is used as the initial value for feedback control. Therefore, in this case, the learning value is determined in step S7. The capacity of the lock-up clutch is determined by subtracting the constant value α from S (this is updated sequentially, so the latest value is used) to obtain the learned value. A control value that is larger than the capacity corresponding to S by a certain amount is read as the initial value Di.

This learning is worth it. 8 is the control value required to maintain the speed ratio of the lock-up clutch within the reference range at that time, and by using this, it is possible to set the optimum initial control value Di at that time, It is possible to set the engagement capacity without any problems. Note that when transitioning to a deceleration state, torque fluctuations are involved, so the above initial value is the learned value in order to absorb this fluctuation. An initial value Di is set that is a larger capacity than the capacity based on S.

When the initial value Di is set in this way, the subsequent control is the same as the feedback control when the operating state is in the feedback region B (the control shown in FIGS. 6 to 9), and the lock-up The clutch is maintained in a semi-engaged state with a constant slip to achieve deceleration. This ensures engine braking force while also preventing surge vibrations.
Occurrence of commotion sounds etc. is prevented.

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 obtained when driving on a slope and when driving on a flat road. The duty ratio required for this purpose 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). ) is used as the learning value, the engine torque component is set from the engine torque at that time, and the driving condition at that time (
For example, the duty ratio is set to suit the conditions (such as driving on a flat road or driving up a hill).

This will be explained using FIG. 12. As an example,
50 km/) (Consider the duty ratio setting during normal driving. In this case, the engine torque is 4 kg.
-m and the learning value of the feedback component is 20% (on side), the engine torque component is 20% (on side) as seen from the figure, and the feedback component is 50×(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.

Consider a case where the accelerator pedal is subsequently released from the accelerator pedal while the vehicle is running in the above state and the vehicle enters a deceleration state. Assuming that the engine torque immediately after this transition remains at 4 kg-m, the engine torque component is 20%.

On the other hand, the learned value is 20% on the on side (80% on the off side), but a value that is strengthened by 20%, that is, 40% on the on side (60% on the off side), is used as the initial value,
The initial value of the feedback component is 50X (40/100
)=20%. Therefore, the initial value of the on-duty ratio of the second solenoid valve 8 in this case is 40%, which is the sum of both components.

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 8 are OFF, and the second solenoid valve 8 is also 0FF1, that is, the on-duty is 0%.

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 sum of a feedback component, which is the latest learned value plus a constant value for increasing the engagement capacity, and an engine torque component. In the second semitight region,
The first solenoid valve 7 is turned on, and the feedback component of the second solenoid valve 8 is turned on, that is, 100%.
Therefore, a value corresponding to the engine torque is used as the engine torque component, and the duty ratio is set by the sum of both components, and the timing valve 40 is kept OFF. In the tight region, the first solenoid valve 7
is switched OFF, and the timing valve 40 is switched ON.

In addition, feedback control is performed in the deceleration lock-up region, and immediately after transition to the deceleration lock-up region, this control is controlled by a certain amount to increase the engagement capacity based on the learning value stored in the feedback region. The value strengthened by 100% is set as the initial value, and the feedback component is set by feedback control using this, the engine torque component is set corresponding to the engine torque, and the duty ratio is set by the sum of both components. Ru.

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, according to the control method of the present invention, when the parameter representing the amount of slip between the input side and the output side of the direct coupling mechanism becomes a value within a predetermined reference range during feedback control, The control value of the engagement capacity of the direct coupling mechanism is stored, and when the vehicle shifts to a deceleration state, the initial value of the control value of the engagement capacity of the direct coupling mechanism is determined based on this stored control value, and this The system is configured to perform feedback control of the engagement capacity to maintain the above parameters within the target range using the initial values, but in the feedback range, a certain amount of slip always occurs in the lock-up clutch. The engagement capacity is feedback-controlled.
Since it is possible to accurately grasp the relationship between the control value (duty ratio) and the engagement capacity for the oil temperature at that time in the individual (lock-up clutch), the deceleration state is shifted based on the control value grasped in this way. By setting the initial control value at the time, it is possible to set the optimum engagement capacity, and it is possible to obtain good deceleration running characteristics.

[Brief explanation of the drawing]

Fig. 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, and Fig. 2 shows how the lock-up clutch is engaged based on the relationship between throttle opening and vehicle speed. Graphs showing the regions, Figures 3 to 6 and Figures 8 to 11 are flowcharts showing the operation control details of the solenoid valve that controls the operation of the lock-up clutch, and Figure 7 shows the relationship between the speed ratio and time of the lock-up clutch. 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・
...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. In this method, the engagement capacity is feedback-controlled so that a parameter representing the slip amount between the input side and the output side becomes a value within a predetermined reference range in a predetermined running state, and during this feedback control, the engagement capacity is Based on the control value of the engagement capacity when the parameter reaches a value within the predetermined reference range,
An initial value of the control value of the engagement capacity of the direct coupling mechanism is determined when the vehicle shifts to a deceleration state, and the engagement capacity in the deceleration traveling state is determined based on this initial value to maintain the parameter within the target range. A direct coupling mechanism control method for a fluid power transmission device, characterized in that feedback control of a total capacity is performed.