JPH0611032A - Shift control method of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To smoothly operate engagement change of clutches so as to reduce a shock at shifting, in a shift control method of an automatic transmission for vehicle by which a second frictional engaging means is engaged while releasing engagement of a first frictional engaging means so as to change the turbine rotating speed toward the synchronous rotating speed. CONSTITUTION:After detecting (d-time) synchronization of turbine rotating speed Nt with the synchronous rotating speed Ntj, a solenoid valve for first speed is driven at duty ratio De for a time T1 (d-time and e-time), then the solenoid valve for first speed is driven for a time T2 while gradually increasing the duty ratio De (e-time and f-time), and the solenoid valve for first speed is driven at duty ratio 100% since f-time, so as to perfectly engage a clutch for first speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art An automatic transmission mounted on an automobile is constructed by providing a plurality of friction engagement means such as a hydraulic multi-plate clutch and a hydraulic brake. When the controller switches, the shift change of the automatic transmission is carried out.

For example, when the automatic transmission is downshifted from the second speed to the first speed, the controller disengages the second speed clutch for establishing the second speed according to a predetermined program, and The clutch for the first speed that establishes the first speed is engaged, and the clutch is replaced. At this time, the controller controls the progress state of the disengagement of the second speed clutch and the progress state of the engagement of the first speed clutch, and the rotation speed Nt of the transmission input shaft is controlled.
The change rate (Nt) 'is the target rotation speed change rate (Nt).
i) ', the clutch re-grip operation is advanced so as to increase.

Then, the controller predicts a time point at which the input shaft rotational speed Nt is synchronized with the first speed synchronous rotational speed, and at the time point that is a predetermined time before the predicted synchronous time point, the controller operates the first speed clutch. Starts driving the solenoid valve at 100% duty. As a result, the engagement of the first speed clutch is rapidly advanced, and is completely engaged at the predicted time point.

[0005]

However, the time point at which the input rotation shaft speed Nt is synchronized with the first speed synchronous rotation speed is predicted, and the first speed clutch is rapidly engaged based on this prediction. If, for example, the accelerator pedal is operated during execution of a downshift and the predicted value deviates, a non-synchronized input shaft and output shaft will be suddenly connected, and a large shift shock will occur. There was also such a problem.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a shift control method for an automatic transmission for a vehicle, which can reduce shift shock at the end of a shift.

[0007]

In order to achieve the above object, according to the shift control method of the present invention, the second friction engagement means is engaged while the engagement of the first friction engagement means is released. In the shift control method for a vehicle automatic transmission that shifts the rotation speed of the input shaft toward the synchronized rotation speed after shifting, when it is detected that the rotation speed of the input shaft is synchronized with the synchronized rotation speed after shifting, The shift control method for an automatic transmission for a vehicle is characterized in that the hydraulic pressure of the second friction engagement means is set to a predetermined pressure and then the hydraulic pressure is gradually increased from the predetermined pressure.

At this time, it is desirable to gradually increase the working hydraulic pressure after the predetermined pressure is maintained for the first predetermined time. Further, it is desirable to gradually increase the operating oil pressure over a second predetermined time at a constant increase rate and then supply the maximum oil pressure to the second friction engagement means. Further, it is desirable that the predetermined pressure is determined according to the load state of the engine of the vehicle.

Alternatively, it is desirable that the predetermined initial value is determined according to the input shaft torque.

[0010]

According to the gear shift control method of the present invention, when it is detected that the input shaft rotation speed matches the rotation speed after gear shifting, the operating hydraulic pressure of the second friction engagement means is set to a predetermined hydraulic pressure, The engagement of the friction engagement means is advanced to a predetermined position. After that, the hydraulic pressure is gradually increased to gradually advance the engagement of the second friction engagement means.

[0011]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of an automatic transmission of an automobile that carries out a shift control method according to the present invention. Reference numeral 1 in the drawing denotes an internal combustion engine, and the output of the engine 1 is transmitted to drive wheels (not shown) via an automatic transmission 2.

The automatic transmission 2 comprises a torque converter 4, a gear transmission 3, a hydraulic circuit 5 and a controller 40. The gear transmission 3 includes, for example, a gear train of four forward gears and one reverse gear, and a plurality of gear shift friction engagement means for performing gear shift operation by switching the gear ratio of the gear train. The shift friction engagement means is, for example, a hydraulic clutch or a hydraulic brake.

FIG. 2 is a partial block diagram of the gear transmission 3. A first drive gear 31 and a second drive gear 32 are rotatably arranged around the input shaft 3a. Further, between the first drive gear 31 and the input shaft 3a, and the second drive gear 32.
Hydraulic clutches 33 and 34 are provided between the input shaft 3a and the input shaft 3a. Each drive gear 3
1 and 32 rotate integrally with the input shaft 3a by engagement of the hydraulic clutches 33 and 34, respectively.

The intermediate transmission shaft 35 arranged in parallel with the input shaft 3a is connected to a drive axle via a final reduction gear unit (not shown). The intermediate transmission shaft 35 is provided with a first driven gear 36 and a second driven gear 37, and these driven gears 36 and 37 mesh with the drive gears 31 and 32, respectively. Therefore, when the input shaft 3a and the first drive gear 31 are connected by the hydraulic clutch 33, the rotation of the input shaft 3a is changed by the hydraulic clutch 33, the first drive gear 31, the first driven gear 36,
It is transmitted to the intermediate transmission shaft 35, whereby, for example, the first speed is established. In addition, the hydraulic clutch 34 allows the input shaft 3
When a is connected to the second drive gear 32, the rotation of the input shaft 3a is caused by rotation of the hydraulic clutch 34 and the second drive gear 3.
2, transmitted to the second driven gear 37, the intermediate transmission shaft 35,
Thereby, for example, the second speed is established. That is, the hydraulic clutch 33 is the first speed clutch, and the hydraulic clutch 34 is the second clutch.
Since it is used as a speed clutch, the clutch 33 is hereinafter referred to as a first speed clutch, and the clutch 34 is referred to as a second speed clutch.

While the first speed clutch 33 is engaged, the second speed clutch 33 is released while being disengaged.
By engaging the speed clutch 34, the automatic transmission 2 shifts up from the first speed to the second speed. Conversely, by engaging the first speed clutch 33 while releasing the engagement of the second speed clutch 34 from the state in which the second speed clutch 34 is engaged, the automatic transmission 2 is set to the second position. Downshift from first speed to first speed.

Both clutches 33, 34 are hydraulic multi-plate clutches. FIG. 3 shows a cross section of the first speed clutch 33, which accommodates a friction engagement plate 50, a clutch piston 52, a return spring 53 that urges the clutch piston 50 in a direction away from the friction engagement plate 50, and these members. The clutch retainer 54 and the like are used.

Here, the friction engagement plate 50 is composed of a plurality of clutch plates 50a provided on the clutch retainer 54 side.
And a plurality of clutch discs 50b arranged between the clutch plates 50a.
b is connected to the drive gear 31 side. The clutch retainer 54 is connected to the input shaft 3a.

Then, from the oil passage 14 to the port 51, which will be described later.
When hydraulic oil is supplied into the cylinder formed between the clutch piston 52 and the clutch retainer 54 via the clutch piston 52, the clutch piston 52 moves right in the figure to cause friction between the clutch plate 50a and the clutch disc 50b. Engage. On the other hand, when the hydraulic oil supplied to the cylinder is discharged through the oil passage 14, the clutch piston 52 moves left in the figure by the action of the return spring 53, and the engagement between the clutch plate 50a and the clutch disc 50b is released. .

Generally, in a multi-plate clutch having such a structure, the clutch piston 52 and the friction engagement plate 50 are prevented from contacting each other when the clutch is disengaged so that a so-called drag torque is not generated. A predetermined gap is set between the two. Therefore, in order to control the engagement of the first speed clutch 33,
First, it is necessary to carry out a so-called rattling operation, in which the clutch piston 52 is moved by this gap (ineffective stroke) and is made to stand by at a position immediately before the clutch piston 52 and the clutch plate 50a come into contact with each other. A time Tf is required for this loosening operation.

On the other hand, the first speed clutch 33 in the engaged state
When releasing the supplied hydraulic oil to separate the clutch piston 52 from each other, the clutch plates 50a and the clutch discs 50b are not instantly separated from each other,
Drag torque is generated between the two for a while. Therefore, in order to completely disengage the first speed clutch 33, a hydraulic pressure release time T0 from the start of discharging the hydraulic oil until the drag torque disappears is required.

The second speed clutch 34 is also constructed in the same manner as the first speed clutch 33, and requires a predetermined rattling time Tf 'and a hydraulic pressure release time T0 at the time of engagement and the time of disengagement, respectively. The hydraulic circuit 5 has a duty solenoid valve (hereinafter simply referred to as a solenoid valve) corresponding to each of the above-described speed change friction engagement means, and each speed change friction engagement means, that is, each clutch or brake, is provided. Operate independently of each other. Since each solenoid valve operates each clutch and brake in the same manner, the first speed clutch 3
The solenoid valve for operating 3 will be described with reference to FIG. 4, and description of the other solenoid valves will be omitted.

FIG. 4 shows a part of the hydraulic circuit 5, showing a solenoid valve 1 for controlling the supply and discharge of the hydraulic pressure to and from the first speed clutch 33.
1 (hereinafter, referred to as first speed solenoid valve). The first-speed solenoid valve 11 is a normally closed two-position switching valve and has ports 11a to 11c at three locations.
A first oil passage 13 extending to an oil pump (not shown) is connected to the first port 11a. This first oil passage 13
A pressure regulating valve (not shown) and the like are interposed in the middle of, and the working hydraulic pressure (line pressure) regulated to a predetermined pressure is supplied.

A second oil passage 14 extending to the first speed clutch 33 is connected to the second port 11b, and a third oil passage 15 extending to an oil tank (not shown) is connected to the third port 11c. . These second and third oil passages 14,
Stops 16 and 17 are provided in the middle of 15, respectively. The flow passage area of the throttle 16 provided in the second oil passage 14 is set larger than the flow passage area of the throttle 17 provided in the third oil passage 15. Furthermore, the first speed clutch 3
An accumulator 18 is connected in the middle of the second oil passage 14 between the valve 3 and the throttle 16.

The first speed solenoid valve 11 is electrically connected to the controller 40.
The duty ratio is controlled at a predetermined frequency, for example, 50 Hz. When the solenoid 11e of the first speed solenoid valve 11 is deenergized, the valve body 11f is pressed by the return spring 11g and the first port 1
The communication between the 1a and the second port 11b is blocked, and the second port 11b and the third port 11c are connected.
On the other hand, when the solenoid 11e is energized, the valve body 11f lifts against the spring force of the return spring 11g, and the first port 11a and the second port 11b.
And the communication between the second port 11b and the third port 11c is blocked.

The controller 40 includes a ROM (not shown),
It incorporates a storage device such as RAM, a central processing unit, an input / output device, a counter used as a timer, and the like. On the input side of this controller 40, various sensors, for example N
The t sensor 21, the No sensor 22, the θt sensor 23, etc. are electrically connected. The Nt sensor 21 is a turbine rotation speed sensor that detects the rotation speed Nt of the turbine of the torque converter 4 (that is, the input shaft 3a of the gear transmission 3). The No sensor 22 is a transfer drive gear rotation speed sensor that detects a rotation speed No of a transfer drive gear (not shown). The controller 40 can calculate the vehicle speed V based on this rotation speed No. Then, the θt sensor 23
It is a throttle valve opening sensor for detecting a valve opening θt of a throttle valve arranged in the intake passage (not shown) of the engine 1. Each of these sensors 21 to 23 supplies a detection signal to the controller 40 at every predetermined time period.

The storage device of the controller 40 stores a coupling side friction engagement means control procedure for downshifting from the high speed shift stage to the low speed shift stage, and in the present embodiment, from the second speed to the first speed and the release side friction coefficient. The means control procedure is stored in advance. The controller 40 repeatedly executes these procedures at a predetermined cycle to perform a re-grip operation between the first-speed clutch 33, which is the coupling side, and the second-speed clutch 34, which is the disengagement side. Carry out a shift change.

Each of the control programs is roughly composed of four steps, namely, a first step to a fourth step. The first step is until the controller 40 recognizes the necessity of shifting (in FIG. 13,
Before the point a), the second process is the disengagement side clutch 3 for the second speed.
While completely releasing the engagement of 4 and making the transmission torque 0,
Until the rattling operation of the engaging first-speed clutch 33 is completed (between points a and b in FIG. 13), the third process is the turbine rotation speed Nt while performing the clutch re-engaging operation. Is synchronized with the rotation speed in the first gear (points b to d in FIG. 13), and the fourth process is until the clutch re-engagement is completed (points d to f in FIG. 13). ing.

Next, the controller 40 causes the automatic transmission 2
The procedure for carrying out the shift change will be described. Coupling Side Shift Control First, the coupling side friction engagement means control procedure will be described based on FIGS. 5 to 12 and with reference to FIG. 13. The controller 40 controls the first speed solenoid valve 11 by repeatedly executing a first speed solenoid valve control routine for controlling the first speed clutch 33.

First, the controller 40 executes the first step of this drive routine. That is, step S in FIG.
At 60, the controller 40 sets the flag IZA to 1
It is determined whether or not the above. As will be described later, the flag IZA is set to a value of 1 or more while the controller 40 is performing the downshift according to this program, that is, when the second process and thereafter are being executed. Therefore, when the first step of determining the presence / absence of the downshift gearshift command is being executed, the flag IZA is set to 0.
Is set to, and the controller 40 sets the step S61.
Proceed to.

In step S61, the controller 40
Determines the necessity of downshifting from the second speed to the first speed, for example, based on the vehicle speed V, the throttle valve opening θt, and the like. When it is determined that it is not necessary to downshift to the first speed, that is, when it is determined that it is unnecessary to continue to the second speed in view of the current running state of the vehicle, that is, when there is no shift command. , The controller 40 terminates this routine, and then re-executes this routine at a predetermined time period. That is, the controller 40 performs step S6.
In step 1, the first process is repeatedly executed until the downshift gear shift command is issued.

On the other hand, in step S61, when the controller 40 recognizes the necessity of downshifting from the second speed to the first speed (time a in FIG. 13), the controller 40
Advances to step S62, and therefore, the first process shifts to the second process. When the controller 40 outputs the shift command from the second speed to the first speed, the controller 40 starts the above-described counter and sets the elapsed time T from the time when the shift command is output.
Start measuring a.

In the second process, the controller 40 drives the 1st speed solenoid valve 11 at a duty ratio of 100% to obtain the maximum hydraulic pressure that can be supplied by the 1st speed clutch 3.
3 and the first speed clutch 33 is loosened in the shortest time. In this case, the controller 40 matches the completion of the rattling operation of the first speed clutch 33 with the completion of the disengagement of the second speed clutch 34, which will be described later, at the time point b in FIG. Adjust the operation start time of 11.

In step S62, the controller 4
0 sets the flag IZA to 1. As a result, the flag IZA indicates that the downshift is being performed. Then, the controller 40 proceeds to step S
Proceeding to 64, various stored values are read from the above-mentioned storage device. Specifically, the controller 40 determines that the time T
f, T0 ', T1, T2, duty ratios Da0, De, Dka
Read out. Here, the time Tf is the clearance time of the first speed clutch 33, the time T0 'is the hydraulic pressure release time of the second speed clutch 34, and the times T1 and T2 are the engagement of the first speed clutch 33 in the fourth step. The duty ratio output time, the duty ratio Da0 is the initial duty ratio for feedback controlling the solenoid valve 11 for controlling the clutch 33 after the rattling operation of the first speed clutch 33, and the duty ratio De is the rotation of the turbine. After determining that the speed Nt matches the first-speed synchronous rotation speed Ntj, the duty ratio for driving the first-speed clutch 33 control solenoid valve 11 is defined as the duty ratio Dka of the clutch piston 52 of the first-speed clutch 33. The minimum duty ratio (holding duty ratio) for holding the position in opposition to the biasing force of the return spring 53 is shown.

The loosening times Tf and Tf 'and the hydraulic pressure release times T0 and T0' of the clutches 33 and 34 are the temperature of the hydraulic oil supplied to the clutches 33 and 34, or
It is preferable to make a correction according to the rotational speed of the oil pump described above. The hydraulic oil temperature has a large influence mainly on the viscosity of the hydraulic oil, and therefore has a large influence on the rise time of the hydraulic pressure supplied to the clutch. The lower the hydraulic oil temperature, the more the times Tf, Tf 'and T0, T0' are corrected, and their correction factors are set experimentally. On the other hand, the rotation speed of the oil pump affects the discharge pressure and discharge amount of the oil pump. There is no particular problem when using an oil pump having a large capacity and having a sufficient discharge pressure margin even at low rotation speed, but when using an oil pump having a small capacity, correction is necessary. In this case, when the rotation speed is equal to or lower than the predetermined rotation speed, the lower the rotation speed, the larger the correction needs to be made. Further, the times Tf and Tf ′ are corrected by learning control, respectively, so that the changes with time of the clutches 33 and 34 can be dealt with. Here, as the learning control used, the learning method disclosed in USP 4439920 can be used.

The duty ratio De is determined according to the load state of the engine, the input shaft torque of the turbine, etc., based on a predetermined map stored in the storage device. At this time, the load state of the engine is, for example, the throttle valve opening θt detected by the above-mentioned θt sensor 23.
Alternatively, the determination may be made based on the intake air amount of the engine detected by an air flow sensor (not shown).

After this, the controller 40 proceeds to step S
65, the elapsed time Ta measured by the counter
Read out. Then, the controller 40 proceeds to step S70 of FIG. In step S70, the controller 40 determines whether the second process has ended. Specifically, the controller 40 determines that the elapsed time Ta is 1
It is determined whether it is longer than the rattling time Tf of the speed clutch 33 and longer than the hydraulic pressure release time T0 'of the second speed clutch 34. If this decision is negative,
That is, when the rattling of the first speed clutch 33 is not yet finished and the release of the hydraulic pressure from the second speed clutch 34 is not finished yet, the controller 40 repeats this routine from step S70 to step S70 of FIG. Step S80
Then, the operation for rattling the first-speed clutch 33 is continued.

In steps S80 to S83, the controller 40 controls the rattling time Tf of the first speed clutch 33.
And the hydraulic pressure release time T0 ′ of the second speed clutch 34 are determined, and when the second speed clutch 34 is completely disengaged and the torque transmission amount becomes 0, the first speed clutch 3
To ensure that the clutches 33 and 34 can be smoothly re-griped, set the same timing with the point at which the rattling operation of 3 is completed.
The release start point of the operating oil pressure of the speed clutch 34 and the start point of the rattling operation of the first speed clutch 33 are adjusted.

13 and 28 show a first speed clutch 33.
The case where the rattling time Tf is longer than the hydraulic pressure disengagement time T0 ′ for the second speed clutch 34 is illustrated. In this case,
After the start of the rattling operation of the clutch 33 for the first speed, the time (Tf-T0 ') has elapsed (that is, h in the figure
By starting the hydraulic pressure release of the second speed clutch 34 (from the time point), the rattling operation of the first speed clutch 33 and the hydraulic pressure release of the second speed clutch 34 can be simultaneously completed at the time point b in the figure. it can.

In the case illustrated in FIGS. 13 and 28, the determination result in step S80 is negative, so the controller 40 proceeds to step S81. Then, in step S81, the controller 40 drives the first-speed solenoid valve 11 at a duty ratio of 100%, whereby
The rattling operation of the first speed clutch 33 is started before the hydraulic pressure release of the second speed clutch 34. Therefore, the hydraulic pressure of the first speed clutch 33 starts to rise (FIG. 28).

The controller 40 executes this step S81.
After executing, this routine ends. Then, after a predetermined period of time, in the next execution of this routine,
Since the flag IZA is set to 1 in step S62 described immediately after the shift command is issued, the determination condition of step S60 of FIG. 5 is satisfied, and the controller 40 proceeds from step S60 to step S65. . Then, the controller 40 proceeds to step S70 of FIG. 6 and steps S80 and S81 of FIG. 7 to continue the rattling operation of the first speed clutch 33. This stuffing operation is
This is continued in the section between the time points a and b in FIGS. 13 and 28, whereby the second process proceeds.

When the rattling operation of the first speed clutch 33 is performed, a large amount of hydraulic oil is supplied to the clutch 33, but the clutch piston 52 moves forward accordingly. Therefore, as shown in FIG. 28, the operating hydraulic pressure of the first speed clutch 33 changes substantially constant. on the other hand,
In step S80 described above, the first speed clutch 33
If the second speed clutch 34 hydraulic pressure release time T0 'is longer than the rattling time Tf, the controller 40
Proceeds to step S82. In this case, as shown in FIG. 29, the time point when the engagement of the second speed clutch 34 is completely released and the time point when the rattling operation of the first speed clutch 33 is completed is time point b ′ in the figure. In order to make the values coincide with each other, after the hydraulic pressure release of the second speed clutch 34 is started, the time (T0'-T
It is necessary to start the rattling operation of the first speed clutch 33 after the passage of f) (that is, from the time point h ′).

Therefore, the elapsed time Ta is equal to the time (T0'-
Until Tf) is reached, the rattling operation for the first speed clutch 33 is not performed, and when the condition in step S82 is not satisfied, the controller 40 proceeds to step S8.
3 and set the duty ratio of the 1st speed solenoid valve 11 to 0.
Output in%. The controller 40 executes step S83 while repeatedly executing this program until the condition of step S82 is satisfied, until the elapsed time Ta reaches the time (T0'-Tf). Set the duty ratio to 0% and wait.

When the elapsed time Ta exceeds the time (T0'-Tf) and the condition of step S82 is satisfied while the program is repeatedly executed, the controller 40 proceeds from step S82 to step S81. As a result, the controller 40 keeps driving the first speed solenoid valve 11 at the duty ratio of 100% for the rattling time Tf while repeatedly executing this program. This causes the second step of the program to proceed.

The elapsed time Ta is b in FIG.
When the time point is reached, the rattling operation of the first speed clutch 33 is completed, and as described later, the second speed clutch 34
Is also released. Therefore, the determination result of step S70 becomes affirmative, and the execution of the controller 40 shifts from the second process to the third process. When entering the third process, the controller 40 proceeds to step S71 and determines whether or not the flag IZA is equal to 4. Immediately after the transition from the second process to the third process, the flag IZA is set to 1, and the rotational speed Nt of the turbine should normally not deviate from the second synchronous rotation speed Nti. The controller 40 performs steps S71 to S72, S73, S
After each control of S74 and S75, step S9 of FIG.
It will proceed to 0.

In step S90, the controller 4
0 sets the flag IZA to 2 and proceeds to step S91. In step S91, the controller 40 sets the duty ratio Da of the first speed solenoid valve 11 to the initial duty ratio Da0. Then, the process proceeds to step S92, and the controller 40 determines whether the duty ratio Da is equal to or higher than the holding duty ratio Dka. If the duty ratio Da is equal to or higher than the holding duty ratio Dka, the controller 40 proceeds to step S94 without executing step S93.

On the other hand, if the duty ratio Da is smaller than the holding duty ratio Dka in step S92, the controller 40 proceeds to step S93. When the duty ratio Da is smaller than the holding duty ratio Dka, the 1st speed solenoid valve 11 is operated at the duty ratio Da.
Is driven, the position of the clutch piston 52 of the first speed clutch 33 cannot be held in opposition to the spring force of the return spring 53, and the clutch plate 50a of the friction engagement plate 50 and the clutch disc 50b are mutually displaced. It is necessary to separate and re-tighten. Therefore, in step S93, the controller 40 resets the duty ratio Da to the holding duty ratio Dka that supplies the minimum hydraulic pressure for holding the position of the clutch piston 52, and proceeds to step S94.

In step S94, the controller 4
0 drives the first speed solenoid valve 11 at the duty ratio Da. That is, in this case, the controller 4
0 drives the first speed solenoid valve 11 at the initial duty ratio Da0 (or Dka) (time b in FIG. 13). When step S94 is executed, the controller 40
Terminates this routine.

Next, when this routine is executed, the controller 40 executes steps S60, S65 of FIG.
To Steps S70 to S75. Here, since the flag IZA is set to 2 in step S90 described above, the determination condition in step S75 is satisfied, and the controller 40 proceeds to step S100 in FIG.

In step S100, the controller 40 reads the duty ratio increase amount ΔDa2. The increase amount ΔDa2 is a predetermined value that is set in advance for each downshift mode such as the second speed to the first speed and the third speed to the second speed. Thereafter, the controller 40 adds the increase amount ΔDa2 to the previous duty ratio Da to make a new duty ratio Da in step S101, and proceeds to step S92 of FIG. 8 described above. Then, the controller 40 executes steps S92 to S94 and sets the duty ratio D to the first speed solenoid valve 11 as described above.
Drive with a.

As will be described later, the controller 40 sets the duty ratio Da of the 1st speed solenoid valve 11 until it detects that the turbine rotation speed Nt is out of synchronization with the second speed (from the time point b to the time point c in FIG. 13). It is increased by ΔDa2 every control cycle. As a result, the first speed clutch 33 gradually starts to be engaged from the rattling operation completion position, and the transmission torque is generated by the first speed clutch 33 even if the engine 1 is in the power-off state, and the turbine rotation speed is increased. Nt is second
The first synchronous rotation speed Ntj deviates from the high-speed synchronous rotation speed Nti.
Begins to increase towards (Fig. 13).

Then, this out-of-synchronization progresses, and the rotational difference between the turbine rotational speed Nt and the second synchronous rotational speed Nti becomes Δ.
When Nb is reached, the condition of step S74 of FIG. 6 is satisfied, and accordingly, the controller 40 detects the second speed synchronous rotation disengagement (time c in FIG. 13). When the second speed synchronous rotational deviation is detected, the controller 40 proceeds to step S110 in FIG.

After setting the flag IZA to 3 in step S110, the controller 40 rewrites the above-mentioned initial duty ratio Da0 to the latest duty ratio Da. In order to quickly start the shift control (feedback control of the transmission torque of the first speed clutch 33), it is preferable to set the initial duty ratio Da0 to a value as close as possible to the optimum duty ratio at the time of starting the feedback control. Therefore, as described above, the duty ratio at the time when the synchronous rotation deviation is detected, that is, the shift start time is
Each time the shift control is executed, learning is performed, and this is sequentially updated and stored as the initial duty ratio Da0 (step S11).
1).

After this, the controller 40 proceeds to step S1.
11a, the previous deviation value (Ge) n-1, (G
i) 0 is assigned to n-1 as an initial value, and these are reset. Next, the controller 40 performs step S11.
2, the rate of change (Nt) 'of the turbine rotation speed Nt is obtained. Specifically, the controller 40 obtains an actual turbine rotation speed change rate (Nt) ′ which is a time differential value of the turbine rotation speed Nt based on the turbine rotation speed Nt detected last time and the turbine rotation speed Nt detected this time. The symbol (Nt) ′ represents a time differential value of the turbine rotation speed Nt, and other time differential values are similarly expressed.

Then, in step S113, the controller 40 sets the target turbine rotation speed change rate (Nia) '.
Read out. This target turbine speed change rate (Ni
a) ′ is a predetermined value set in advance for each mode of each downshift, and is stored in the storage device of the controller 40 in advance. After that, the controller 40 proceeds to step S114, where the actual turbine rotation speed change rate (N
t) 'and the target turbine rotation speed change rate (Nia)' based on the difference, the duty ratio correction amount (feedback correction amount)
Calculate ΔDaf. Various methods can be applied to obtain the correction amount ΔDaf, and there is no particular limitation, but a conventionally known calculation method in PID control can be applied.

FIG. 14 shows an example of a concrete correction amount calculation procedure in this PID control. First, in step S300, the controller 40 subtracts the actual turbine rotation speed change rate (Nt) 'from the target turbine rotation speed change rate (Nia)' to obtain the current deviation value (Ge) n.
After this, the controller 40 performs steps S301 to S3.
03 to execute the integral correction amount (Gi) n and the proportional correction amount Gp.
And the differential correction amount Gd.

More specifically, the controller 40
In step S301, the previous integral correction amount (G
i) n-1 is added to a value obtained by multiplying the deviation value (Ge) n of this time by a predetermined coefficient Ki to obtain the integrated correction amount (Gi) n of this time. Next, in step S302, the current deviation value (Ge)
The proportional correction amount Gp is obtained by multiplying n by a predetermined coefficient Kp.
Then, in step S303, the current deviation value (Ge)
The differential correction amount Gd is obtained by multiplying the value obtained by subtracting the previous deviation value (Ge) n-1 from n by the predetermined coefficient Kd.
After that, the controller 40 proceeds to step S304 and obtains the duty ratio correction amount ΔDaf as the total value of the integral correction amount (Gi) n, the proportional correction amount Gp, and the differential correction amount Gd. The predetermined coefficients Ki, Kp, Kd are experimentally set to appropriate values.

The controller 40 then proceeds to step S
Proceeding to step 305, the previous deviation value (Ge) n-1 reset in step S111a is calculated as the deviation value (Ge) n obtained this time.
Is set and stored, and the process proceeds to step S306, where the previous integrated correction amount (Gi) n-1 reset in step S111a is calculated as the integrated correction amount (Gi) n obtained this time.
After this is set and stored, this correction amount calculation routine ends.

Returning to FIG. 10, the controller 40 proceeds to step S115 and sets the duty ratio Da to the initial value D
It is set as the sum of a0 and the correction amount ΔDaf. After that, the controller 40 proceeds to step S92 of FIG. 8 and executes steps S92 to S94 to drive the first speed solenoid valve 11 at the duty ratio Da as described above. In this way, the controller 40 starts the feedback control to increase the turbine rotation speed Nt such that the actual turbine rotation speed change rate (Nt) ′ becomes equal to the target turbine rotation speed change rate (Nia) ′.

Next, when this routine is executed, the controller 40 executes steps S60, S65, S70-S.
73 is sequentially executed. Since the flag IZA is set to 3 in step S110 described above, the controller 40 determines from step S73 to step S of FIG.
Proceed to 112. Then, the controller 40 executes steps S112 to S115 and S92 to S94 to set the duty of the first speed solenoid valve 11 so that the actual turbine rotation speed change rate (Nt) ′ is equal to the target rotation speed change rate (Nia) ′. Feedback control of the rate Da is performed. That is, the controller 40 continues the feedback control while repeatedly executing this program until it detects that the turbine rotation speed Nt is synchronized with the first synchronous rotation speed Ntj (time point d in FIG. 13). As a result, the engagement of the first speed clutch 33 gradually progresses.
Since the speed clutch 34 is also operated, the turbine rotation speed Nt increases as shown in FIG. 13.

When the turbine rotation speed Nt approaches the first speed synchronous rotation speed Ntj, specifically, the absolute value of the difference between the turbine rotation speed Nt and the first speed synchronous rotation speed Ntj is a predetermined value ΔNf ( For example, if the speed is reduced to 50 rpm or less,
The controller 40 detects the synchronization of the turbine rotation speed Nt with the first synchronous rotation speed Ntj (time d in FIG. 13). When the completion of synchronization is detected, the determination result of step S72 of FIG. 6 becomes affirmative, and the controller 40 proceeds to step S121 of FIG. 11 and shifts the execution thereof from the third process to the fourth process. At this time, the controller 40
Starts the measurement of the elapsed time Tb after the transition to the fourth process by using the counter.

In step S121, the controller 40 sets the flag IZA to 4. Then, the controller 40 proceeds to step S122 and sets the duty ratio Da to the duty ratio De read in step S64. Then, the controller 40 executes steps S92 to S94 of FIG. 8 to drive the first speed solenoid valve 11 at the duty ratio Da (= De). That is, FIG.
At time d during 3, the duty ratio Da of the first-speed solenoid valve 11 is rapidly increased to the predetermined duty ratio De.

Next, since the flag IZA is set to 4 in step S121 described above, the determination result of step S71 becomes affirmative, and step S1 of FIG.
Proceed to 30. In step S130, the controller 40
Reads the elapsed time Tb. And step S
In step 131, the elapsed time Tb is compared with the engagement duty ratio output time T1. That is, until the elapsed time Tb reaches the engagement duty ratio output time T1, when the controller 40 repeatedly executes this routine, the controller 40 proceeds from step S131 to S132 and sets the previously output duty ratio Da, that is, the duty ratio De to 1 The high speed solenoid valve 11 is continuously driven (time point d to time point e in FIG. 13).

When the elapsed time Tb reaches the engagement duty ratio output time T1 (time e), the controller 40
Advances from step S131 to step S133 to determine whether the elapsed time Tb has reached the time (T1 + T2). Then, if this condition is not satisfied, the controller 40 proceeds to step S134 and reads the duty ratio increase amount ΔDa1. This duty ratio increase amount Δ
Like the above-mentioned increase amount ΔDa2, Da1 is preset to an appropriate value for each downshift mode, for example.

After this, the controller 40 proceeds to step S
The process proceeds to step 135, and the increase amount ΔD is added to the previous duty ratio Da.
A1 is added to obtain a new duty ratio Da. Then, the controller 40 proceeds to step S92 in FIG. 8 and executes steps up to step S94 to drive the first speed solenoid valve 11 at the duty ratio Da (= Da + ΔDa1). The controller 40 gradually increases the duty ratio Da of the first speed solenoid valve 11 at a predetermined rate (ΔDa1) while repeatedly executing this routine until the elapsed time Tb reaches the time (T1 + T2). The operating oil pressure of the clutch 33 is gradually increased (from time e to time f in FIG. 13).

When the elapsed time Tb reaches the time (T1 + T2) at time f in FIG. 13, the determination condition is met in step S133, so the controller 40 proceeds to step S136. In step S136, the controller 40 drives the first speed solenoid valve 11 at a duty ratio of 100%. As a result, the first speed clutch 33 can be completely engaged, and as described later, the second speed clutch 34 is also completely disengaged, so that the re-grabbing of the clutches 33, 34 is completed, The downshift of the automatic transmission 2 from the second speed to the first speed is completed.

In the section from the time point d to the time point e in the figure, it is not always necessary to continue driving the first speed solenoid valve 11 at the duty ratio De. That is, the controller 40 may be configured to gradually increase the duty ratio Da by the predetermined increase amount ΔDa1 ′ even in the section from the time point d to the time point f. After that, the controller 40 proceeds to step S137, sets the flag IZA to 0 and resets it, and then ends this routine.

Note that, as shown by the broken line in FIG. 13, when the turbine rotation speed Nt starts to rise and deviates from the second speed synchronous rotation speed Nti during the rattling operation of the first speed clutch 33, The controller 40 waits for the completion of the rattling operation and then performs steps S70 to S71 to S7 in FIG.
4, the feedback control after step S110 in FIG. 10 is immediately started. Release Side Shift Control Next, the release side friction engagement means control procedure will be described based on FIGS. 15 to 26 with reference to FIG.
The controller 40 controls the second speed solenoid valve 11 ′ that operates the second speed clutch 34 by repeatedly executing the second speed solenoid valve control routine. Although described above, the second speed solenoid valve 11 ′ has the same configuration as the first speed solenoid valve 11, and therefore its illustration is omitted.

The controller 40 first executes the first step of this control routine. That is, in step S160 of FIG. 15, the controller 40 sets the flag IZR.
Is determined to be 1 or more. As will be described later, the flag IZR is set to a value of 1 or more while the controller 40 is performing the downshift according to this control procedure, that is, when the second process and thereafter are being executed. Therefore, when the first step of determining the presence / absence of the downshift gearshift command is being executed, the flag IZR is set to 0, and the controller 40 determines in step S1.
Proceed to 61.

In step S161, the controller 40
Similarly to step S61 of FIG. 5, it is determined whether or not there is a shift command for downshifting from the second speed to the first speed.
If there is no shift command, the controller 40
Terminates this routine, and step S161
The first process is repeatedly executed until there is a downshift gear shift command in.

On the other hand, if there is a gear shift command (time a in FIG. 13), the controller 40 proceeds from step S161 to step S162, and accordingly shifts from the first step of the program to the second step. At this time, the controller 4
When 0 is set, the counter is used to start the measurement of the elapsed time Ta from the output of the shift command. The elapsed time Ta is a time common to the elapsed time Ta in the above-described first speed solenoid valve control routine, and when the execution of the first speed solenoid valve control routine has already shifted to the second step. , The time Ta after the second process on the coupling side,
It is commonly used as the time Ta after the second process on the release side.

In the second step, the controller 40 sets the duty ratio of the second speed solenoid valve 11 'to 0% and disengages the second speed clutch 34 in the shortest time. In this case, the controller 40 operates as described above. As described above, in order to make the completion of the disengagement of the second speed clutch 34 and the completion of the rattling operation of the first speed clutch 33 at the time point b in FIG. 13 and FIG. 28, the second speed solenoid valve 11 Adjust the operation start time of '. This control will be described later.

In step S162, the controller 40 sets the flag IZR to 1. As a result, the flag IZR indicates that the downshift is being performed. Then, the controller 40 proceeds to step S164 and reads various stored values. More specifically, the controller 40 controls the times Tf, T0 ′, T
Read 1, T2 and duty ratios Dr0 and Dkr. here,
As described above, the times Tf and T0 'are the play-back time of the first speed clutch 33, the hydraulic pressure release time of the second speed clutch 34, and the duty ratio Dr0 is the second speed clutch 3 respectively.
The initial duty ratio of the second speed solenoid valve 11 'after the hydraulic pressure release of No. 4 is the second speed for maintaining the position of the clutch piston of the second speed clutch 34 in the state where the transmission torque is 0. The duty ratios of the respective solenoid valves 11 'are shown.

After this, the controller 40 proceeds to step S
After proceeding to step 165 and reading the elapsed time Ta,
6 to step S170. In step S170,
The controller 40 determines whether or not it is time to start the disengagement of the second speed clutch 34. Specifically, the controller 40 determines that the hydraulic pressure release time T0 'of the second speed clutch 34 is shorter than the rattling time Tf of the first speed clutch 33, and the elapsed time Ta is the time (Tf-T).
0 ') It is judged whether it is less than or equal to.

When the rattling time Tf is longer than the hydraulic pressure release time T0 ', the time point when the second speed clutch 34 is completely disengaged and the time point when the first speed clutch 33 completes the rattling operation. In order to make B and B coincide with each other at the time point b, after the rattling operation of the first speed clutch 33 is started, the time (Tf-T
It is necessary to start the disengagement of the second speed clutch 34 after the passage of 0 ').

In the cases shown in FIGS. 13 and 28, the rattling time Tf is longer than the hydraulic pressure release time T0 '. Therefore, when the elapsed time Ta has not reached the time (Tf-T0'), That is, from the time point a to the time point h in FIG. 13, the controller 40 proceeds to step S180 in FIG. 17 and sets the second speed solenoid valve 11 ′ to the duty ratio 100.
% To continue driving to suspend the disengagement of the second speed clutch 34.

Then, the controller 40 determines that the elapsed time T
a reaches the time (Tf-T0 ') (FIGS. 13 and 28).
This routine is repeatedly executed until the middle h), and steps S160 and S165 of FIG. 15, step S170 of FIG. 16 and step S180 of FIG. 17 are repeated.
The second speed clutch 34 is held at the engagement position. Note that FIG.
As shown in FIG. 9, when the hydraulic pressure release time T0 ′ is longer than the clearance reducing time Tf, the controller 40 determines step S175 described later, and then step S in FIG.
Proceeding to 185, the disengagement is started with the duty ratio of the second speed solenoid valve 11 ′ set to 0% from the time point a ′ in the figure.

Returning to FIG. 13, when the elapsed time Ta reaches the time (Tf-T0 ') at time h in the figure, the condition in step S170 of FIG. 16 becomes negative, so the controller 40 proceeds to step S171. . Here, in step S162 described above, since the flag IZR is set to 1, and normally the turbine rotation speed Nt is not considered to have passed the second synchronous rotation speed Nti, the controller 40 determines , After executing the determinations of steps S171 to S172 to S174,
Proceed to 175.

In step S175, the controller 40 determines whether the elapsed time Ta is larger than the times Tf and T0 '. Now, the elapsed time Ta is the time (T
Since it has just reached f-T0 '), the condition of step S175 becomes negative, and the controller 40 proceeds to step S185 of FIG. Then, the controller 40 drives the second speed solenoid valve 11 'at a duty ratio of 0% to start the disengagement of the second speed clutch 34 (time h in FIG. 13). As a result, the hydraulic pressure of the second speed clutch 34 is
It decreases sharply (Fig. 28).

Then, the controller 40 repeatedly executes this routine to drive the second speed solenoid valve 11 'at the duty ratio of 0%.
When it reaches 0 '(time point b in FIG. 13), the second speed clutch 3
The engagement of No. 4 is completely released, and the transmission torque becomes zero. At the same time, the rattling operation of the first speed clutch 33 is completed as described above. As a result, the clutches 33, 34 are smoothly re-clutched, and the shift control means shifts from the second process to the third process.

When the condition of step S175 of FIG. 16 is satisfied, the controller 40 causes the step S19 of FIG.
0, the duty ratio D of the second speed solenoid valve 11 '
The read duty ratio Dkr is substituted for r. When the second speed solenoid valve 11 'is driven at this duty ratio Dkr, the clutch piston position of the second speed clutch 34 and the hydraulic pressure are held constant. 2nd speed clutch 3
The clutch piston of No. 4 is at a position immediately after the engagement is completely released, that is, a position immediately before the engagement, and therefore, when the second speed solenoid valve 11 ′ is driven at the duty ratio Dkr,
The clutch piston of the second speed clutch 34 stands by at the position immediately before the start of engagement.

Then, after setting the duty ratio Dr to the duty ratio Dkr as described above, the controller 40
The holding duty ratio is determined in step S192, and the process proceeds to step S194. In step S192, the controller 40 determines whether the duty ratio Dr is equal to or higher than the holding duty ratio Dkr described above. This determination is to prevent the duty ratio Dr of the second speed solenoid valve 11 'from being set to be equal to or lower than the above-mentioned holding duty ratio Dkr in the feedback control described later.

The duty ratio Dr is the holding duty ratio Dkr
If the value is smaller than the above value, when the second speed solenoid valve 11 ′ is driven at this duty ratio Dr, the position of the clutch piston of the second speed clutch 34 can be held in opposition to the spring force of the return spring 53. Instead, the friction engagement plates 50 (the clutch plate 50a and the clutch disc 50b) are separated from each other. Therefore, a rattling operation is required to start the re-engagement of the second-speed clutch 34. Therefore, if the duty ratio Dr is greater than or equal to the holding duty ratio Dkr, the controller 40 determines in step S1.
If the duty ratio Dr is smaller than the held duty ratio Dkr without executing 93, the controller 40 executes step S193 and holds the duty ratio Dr at the position of the clutch piston. Then, the holding duty ratio Dkr for supplying the minimum hydraulic pressure is reset, and the process proceeds to step S194.

In step S194, the controller 40
Drives the second speed solenoid valve 11 'at the duty ratio Dr. Immediately after the hydraulic pressure is released from the second speed clutch 34 (time point b in FIGS. 13 and 28), the controller 40 sets the second speed solenoid valve 11 ′ at the duty ratio Dkr.
Drive. The controller 40 continues to drive the second speed solenoid valve 11 'at the holding duty ratio Dkr by repeatedly executing this routine at a predetermined control cycle.
This state is continued at least until the controller 40 detects the second speed synchronous rotation deviation of the turbine rotation speed Nt (time point c in FIG. 13). As a result, the second-speed clutch 34 is held at the position immediately before the start of engagement, as described above.

When the controller 40 detects the deviation (out-of-synchronization) of the turbine rotation speed Nt from the second synchronous rotation speed Nti at the time point c in FIG.
The condition of step S174 of is satisfied, and step S200 of FIG. 20 is executed. Controller 4
In step S200, the flag IZR is set to a value of 2 which means the start of gear shift, and the process proceeds to step S201. In step S201, the magnitude relationship between the elapsed time Ta and the rattling time Tf and the hydraulic pressure release time T0 'is checked to determine whether the disengagement of the second speed clutch 34 and the rattling operation of the first speed clutch 33 are performed. Determine if it is complete.

When this determination is negative, it means that the above-mentioned out-of-synchronization is detected while the hydraulic pressure of the second speed clutch 34 is being released (time c'in FIG. 13). In such a situation, before the stored hydraulic pressure release time T0 'elapses,
Actually, it occurs when the hydraulic pressure release of the second speed clutch 34 is completed and the turbine rotation speed Nt increases. In such a case, the controller 40 proceeds to step S202.
The process proceeds to step S206 without executing S204 to S204, and immediately starts feedback control (feedback control of transmission torque) of the second speed solenoid valve 11 'described later.

On the other hand, if the determination result in step S201 is affirmative and both the disengagement of the clutches 34 and 33 and the rattling operation have been completed before the out-of-sync detection, the controller 40 proceeds to step S202. An actual turbine rotation speed change rate (Nt) ′ of the turbine rotation speed Nt is obtained. Then, in step S203, the controller 4
0 reads the target turbine rotation speed change rate (Nir) ′ for controlling the hydraulic pressure of the second speed clutch 34. The target turbine rotation speed change rate (Nir) ′ is a predetermined value set for each downshift mode, and the target turbine rotation speed change rate for hydraulic control of the first speed clutch 33 described above. (Nia) 'is set so as to be equal to or greater than (Nia)' and is stored in the storage device of the controller 40 in advance.

On the contrary, when the target turbine rotational speed change rate (Nia) 'of the first speed clutch 33 is set to be equal to or higher than the target turbine rotational speed change rate (Nir)' of the second speed clutch 34, When the operating state is the power-off state, the first-speed clutch 33 tries to increase the turbine rotation speed Nt based on the target turbine rotation speed change rate (Nia) ′ that is set to a large value, and is thus controlled to the engagement side. . Further, the second speed clutch 34 tries to lower the turbine speed Nt based on the target turbine rotation speed change rate (Nir) ′ that is set small, so that the second speed clutch 34 is also controlled to the engagement side. Therefore, both the clutches 33 and 34 may be in the engaged state, and interlock may occur.
In the present invention, since (Nir) '>(Nia)' is set, such interlock can be prevented.

After this, the controller 40 proceeds to step S
In step 204, the calculated actual turbine rotation speed change rate (N
t) ′ and the read target turbine rotation speed change rate (N
ir) '. The actual turbine rotation speed change rate (Nt) 'is equal to the target turbine rotation speed change rate (Ni
If r) ′ or less (if the determination result of step S204 is negative), the controller 40 determines in step S205.
19, the duty ratio Dr is kept set to the holding duty ratio Dkr described above, and the process proceeds to step S192 in FIG. = Dk
It is driven by r) (time point c in FIG. 13).

Although different from the example shown in FIG. 13,
When the out-of-synchronization is detected (time point c in FIG. 13), the actual turbine rotation speed change rate (Nt) 'is already larger than the target turbine rotation speed change rate (Nir)', and step S204
If the determination result of is affirmative, the controller 40
In step S206, the flag IFB is set to 1 to store the start of the feedback control, and then in step S207, the duty ratio Dr is set to the initial duty ratio Dr0 of the feedback control. After that, the controller 40 proceeds to step S192 of FIG. 19, checks whether the current duty ratio Dr is equal to or less than the holding duty ratio Dkr, and then drives the second speed solenoid valve 11 ′ with the duty ratio Dr, Start feedback control.

Next, when the controller 40 executes this routine, the flag IZR is set to 2 in step S200.
Therefore, the determination result of step S173 is affirmative, and the process proceeds to step S210 of FIG. The controller 40 performs step S as in the case described above.
After obtaining the actual turbine rotation speed change rate (Nt) 'at 210, the target turbine rotation speed change rate (Nir)' and the first speed clutch 33 for controlling the second speed clutch 34 are controlled at steps S211 and S212. The target turbine rotation speed change rate (Nia) ′ for reading is read.

Then, in step S213, it is determined whether or not the elapsed time Ta is longer than the rattling time Tf and the hydraulic pressure release time T0 '. When this determination result is negative, it means that the above-mentioned out-of-synchronization is detected during the hydraulic pressure release of the second speed clutch 34, as in the case where the determination result is negative in step S201 described above (Fig. 13 point c '). In such a case, the controller 40 proceeds to step S224 of FIG. 22 and immediately starts the feedback control of the second speed solenoid valve 11 'described later.

On the other hand, in step S213, when the elapsed time Ta is longer than the rattling time Tf and the hydraulic pressure release time T0 ', the controller 40 determines in step S2.
In step 14, it is determined whether or not the flag IFB is 1. Here, in the case of the example of FIG. 13, since the step S206 has not been executed immediately after the detection of the out-of-synchronization and the flag IFB has been reset, the controller 40 does
To step S220.

In step S220, the controller 40 again compares the actual turbine rotation speed change rate (Nt) 'with the target turbine rotation speed change rate (Nir)'. The controller 40 changes the actual turbine rotation speed change rate (N
t) 'exceeds the target turbine rotation speed change rate (Nir)', the second speed solenoid valve 11 'is set to the duty ratio Dkr.
Continue to be driven at, and the feedback control is started after the actual turbine rotation speed change rate (Nt) 'exceeds the target turbine rotation speed change rate (Nir)'.

FIG. 13 shows a case where the actual turbine rotation speed change rate (Nt) 'detected immediately after the out-of-synchronization detection is smaller than the target turbine rotation speed change rate (Nir)'. Therefore, the controller 40 proceeds from step S220 to step S221 and continuously sets the holding duty ratio Dkr to the duty ratio Dr. And FIG.
After proceeding to step S192 of 9, it is checked whether the current duty ratio Dr is equal to or less than the holding duty ratio Dkr,
The duty ratio Dr (=
Drive with Dkr).

The controller 40 controls the actual turbine rotation speed change rate (N
t) ′ is equal to or less than the target turbine rotation speed change rate (Nir) ′, and the second speed solenoid valve 11 ′ is repeatedly driven at the duty ratio Dr (= Dkr). On the other hand, as shown in FIG. 13, when the actual turbine rotation speed change rate (Nt) 'increases and exceeds the target turbine rotation speed change rate (Nir)' (time j), the controller 40
Starts feedback control as described above.
That is, since the determination result in step S220 is affirmative, the controller 40 proceeds to step S222, sets 1 in the flag IFB, and stores the start of feedback control. After that, in step S233, the duty ratio Dr is set to the initial duty ratio Dr0 as the feedback initial value, and steps S192 to S194 are executed to execute the second speed solenoid valve 1
Feedback control for driving 1'at a duty ratio Dr (= Dr0) is started (time j in the figure).

Then, when the controller 40 next executes this routine, in step S222,
Since the flag IFB is set to 1, the determination result of step S214 is affirmative, and the process proceeds to step S215. Then, in step S215, the controller 40 compares the actual turbine rotation speed change rate (Nt) 'with the target turbine rotation speed change rate (Nia)' for controlling the first speed clutch 33. Since the actual turbine rotation speed change rate (Nt) 'is larger than the target turbine rotation speed change rate (Nia)', the controller 40
Proceeds from step S215 to step S225 in FIG.

In step S225, the controller 40
Determines the duty ratio correction amount ΔDrf from the difference between the actual turbine rotation speed change rate (Nt) ′ and the target turbine rotation speed change rate (Nir) ′ for controlling the second speed clutch 34. The calculation method of the correction amount ΔDrf is not particularly limited, but the same calculation as the feedback correction amount ΔDaf of the first speed solenoid valve 11 described above is performed.

The controller 40 then proceeds to step S
In step 226, the duty ratio Dr is set to a value obtained by adding the correction amount ΔDrf to the initial duty ratio Dr0. After that, the controller 40 proceeds to step S192 of FIG. 19 to check whether the current duty ratio Dr is equal to or less than the holding duty ratio Dkr, and then the second speed solenoid valve 11 ′.
Is driven at the set duty ratio Dr.

The controller 40 repeatedly executes this routine from the time point j to the time point k in FIG. 13 while performing steps S160, S165, S170 to 173.
S210-S215, S225, S226, S192-
Proceeding to 194, the actual turbine rotation speed change rate (Nt) '
The duty ratio of the second speed solenoid valve 11 ′ is continuously feedback-controlled so as to equalize the target turbine rotation speed change rate (Nir) ′.

At this time, as described above, the engagement of the first speed clutch 33 also progresses, so that at the time point k in FIG. 13, the actual turbine rotation speed change rate (Nt) 'controls the first speed clutch 33. If it becomes smaller than the target turbine speed change rate value (Nia) 'for
215 is satisfied, and the controller 40 performs step S
Proceed to 216.

In step S216, the controller 40
Sets the flag IFB to 0 and resets it, and stores that the feedback control is released. And
The controller 40 proceeds to step S221 of FIG. 22 and sets the duty ratio Dr to the holding duty ratio Dkr, and then proceeds to step S192 of FIG. 19 to perform the above-mentioned check, and then the second speed solenoid valve 11 ′. Are driven at a duty ratio Dr (= Dkr) (at time k in FIG. 13). That is, the second speed clutch 34 is again made to stand by at the position immediately before the engagement.

Then, the controller 40 repeatedly executes this routine, and the second speed solenoid valve 11 '
Continue to be driven with the holding duty ratio Dkr (between time points k and d in FIG. 13). As a result, as described above, the engagement of the first speed clutch 33 is also in progress, so that the turbine rotation speed Nt increases as shown in FIG. 13. Then, at the time point d in FIG. 13, the controller 40 determines that the first rotation speed Nt of the turbine rotation speed Nt.
The synchronization with tj is detected (step S172). And
At this point, step S230 of FIG. 23 is executed, and the process shifts from the third process to the fourth process. At this time, the controller 40 starts measuring the elapsed time Tb after the transition to the fourth process.

The elapsed time Tb is the same time as the elapsed time Tb in the above-described first speed solenoid valve control routine, and the execution of the first speed solenoid valve control routine has already shifted to the fourth step. In this case, the time Tb after the passage of the fourth step in the first speed solenoid control routine
Is commonly used as the time Tb after the lapse of the fourth step in the second speed solenoid valve control routine.

The controller 40 sets the flag IZR to 3 in step S230. Then, the controller 40 proceeds to step S232 and proceeds to the elapsed time T
Read b. After that, the controller 40 proceeds to step S233 and sets the elapsed time Tb to the above-mentioned time T
Compare with the sum of 1 and T2. Now, the controller 40 has just detected the first speed synchronization in step S172, and therefore the elapsed time Tb is smaller than the time (T1 + T2). For this reason, the controller 40 performs step S2
In step 34, it is determined whether or not the flag IFB is set to 1.

At the time point when the first speed synchronization is detected, the flag IF
If B is reset, controller 40
Proceeds from step S234 to step S240 in FIG. In step S240, the controller 40 sets the flag IFB to 1. As a result, the flag IFB indicates that the feedback control has started. Then, the controller 40 proceeds to step S241 and substitutes the above-mentioned initial duty ratio Dr0 of the feedback control for the duty ratio Dr. After that, the controller 40 proceeds to step S192 of FIG. 19, and further executes step S194O to drive the second speed solenoid valve 11 ′ at the duty ratio Dr (time d in FIG. 13).

Next, when this routine is executed, the controller 40 executes steps S160, S165 and S17.
0, proceed to S171. Step S2 of FIG. 23 described above
Since the flag IZR is set to 3 in 30, the controller 40 starts from step S171 in FIG.
3 proceeds to step S232. After reading the elapsed time Tb in step S232, the controller 40
In step S233, the elapsed time Tb and the time (T1 +
Compare with T2). Then, since the elapsed time Tb has not reached the time (T1 + T2) between the time point d and the time point f in FIG. 13, the determination result in step S233 is negative, and the controller 40 proceeds to step S234.

In step S234, since the flag IFB is set to 1 in step S240 described above, the controller 40 causes the controller 40 to execute step S24 in FIG.
Go to 4. In step S244, the controller 4
0 calculates the actual turbine rotation speed change rate (Nt) ′ of the turbine rotation speed Nt. Then, in step S245, the controller 40 sets the target turbine rotation speed change rate (Nir) 'based on the map stored in the storage device.
Read out.

FIG. 27 shows the relationship between the target turbine rotational speed change rate (Nir) 'to be read and the rotational speed difference Ns. The controller 40 first determines the turbine rotation speed Nt.
And a rotational speed difference Ns (= Nt−K2 · No) between the rotational speed No of the transfer drive gear detected by the No sensor 22 and a value obtained by multiplying the second gear ratio K2.
And a target turbine rotation speed change rate (Nir) ′ is determined according to the value of the rotation speed difference Ns.

That is, when the rotational speed difference Ns has a negative value, the target turbine rotational speed change rate (Nir) 'is set to a positive value, and the rotational speed difference Ns increases in the negative direction. Along with this, the target turbine rotation speed change rate (Nir) ′ also increases. Further, the rotation speed difference Ns is 0 or more and the predetermined value Δ
When Nf or less, the target turbine rotation speed change rate (N
ir) 'is set to a positive predetermined value. Further, when the rotational speed difference Ns is larger than ΔNf, the target turbine rotational speed change rate (Nir) ′ is set to a negative value, and the target turbine rotational speed change rate increases as the rotational speed difference Ns increases. (Nir) 'decreases.

Returning to FIG. 25, the controller 40 proceeds to step S246, where the actual turbine rotation speed change rate (N
The duty ratio feedback correction amount ΔDrf is determined based on the difference between t) ′ and the target turbine rotation speed change rate (Nir) ′. The calculation method of this correction amount ΔDrf is 1
It is calculated in the same manner as the feedback correction amount ΔDaf of the speed solenoid valve 11.

The controller 40 then proceeds to step S
In step 247, the duty ratio Dr is set to the addition value of the feedback initial value Dr0 and the correction amount ΔDrf, and then steps S192 to S194 of FIG. Drive with Dr. The controller 40 continues the feedback control of the second speed clutch 34, and the elapsed time Tb is the time (T1
When (+ T2) is reached (at time f in FIG. 13), the determination result of step S233 of FIG. 23 becomes affirmative, and therefore the controller 40 proceeds from step S233 to step S250 of FIG.

In step S250, the controller 40 drives the second speed solenoid valve 11 'at a duty ratio of 0%. As a result, the engagement of the second speed clutch 34 is completely released, and, as described above, the first speed clutch 33 is completely engaged. The downshift of the transmission 2 from the second speed to the first speed is completed.

Thereafter, the controller 40 proceeds to step S
In step 251, each of the flag IZR and the flag IFB is set to 0 and reset, and then this routine ends. In the feedback control of the present embodiment, the actual turbine rotation speed change rate (Nt) 'has been described as an example of the shift state quantity of the automatic transmission 2, but the shift state quantity is not limited to this. Without, for example,
It may be the turbine rotation speed Nt or the change rate (Nt) ″ of the actual turbine rotation speed change rate (Nt) ′.

[0114]

As described above, according to the shift control method of the present invention, when it is detected that the input shaft rotation speed matches the rotation speed after the gear shift, the working hydraulic pressure of the second friction engagement means is set to a predetermined value. Since the hydraulic pressure is set, the engagement of the second frictional engagement means is advanced to a predetermined position, and then the operating hydraulic pressure can be gradually increased, the shift shock at the end of the shift can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic transmission for a vehicle in which a shift control method according to the present invention is implemented.

FIG. 2 is a schematic configuration diagram showing a part of a gear train in the gear transmission of FIG.

3 is a cross-sectional view showing the clutch of FIG.

FIG. 4 is a schematic configuration diagram showing a part of a hydraulic circuit for operating the clutch of FIGS. 2 and 3.

5 is a flow chart showing a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4. FIG.

FIG. 6 shows a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4,
6 is a flowchart following FIG. 5.

FIG. 7 shows a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4,
It is a flowchart following FIG.

FIG. 8 shows a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4.
It is a flowchart following FIG.

9 is a flowchart showing a part of a 1st speed side solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and being a flowchart following FIG. 6;

10 is a flowchart showing a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 6;

FIG. 11 is a flowchart showing a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and continuing from FIG. 6;

FIG. 12 is a flowchart showing a part of a first speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and continuing from FIG. 6;

FIG. 13 is a diagram showing changes in duty ratios and turbine rotation speeds of second-speed and first-speed solenoid valves during downshifting.

14 is a flowchart of a correction amount ΔDaf calculation routine executed in step S114 of FIG.

15 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4. FIG.

16 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 15;

FIG. 17 is a flowchart showing a part of the second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and continuing from FIG. 16;

18 is a flowchart showing a part of the second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 16;

19 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 16;

20 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 16;

21 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 16;

22 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 21.

23 is a flowchart showing a part of the second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 16;

24 is a flowchart showing a part of the second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 23;

25 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart following FIG. 23;

FIG. 26 is a flowchart showing a part of a second speed solenoid valve control routine executed by the controller shown in FIGS. 1 and 4, and is a flowchart continued from FIG. 23;

FIG. 27 is a conceptual diagram of a map for determining a target turbine rotation speed change rate (Nir) ′.

FIG. 28 is a diagram showing a time change of each solenoid valve and clutch hydraulic pressure when the hydraulic pressure release time T0 ′ of the clutch for second speed is equal to or less than the rattling time Tf of the clutch for first speed.

FIG. 29 is a diagram showing a change over time of each solenoid valve and clutch hydraulic pressure when the hydraulic pressure release time T0 ′ of the clutch for 2nd speed is longer than the rattling time Tf of the clutch for 1st speed.

[Explanation of symbols]

 1 Engine 2 Automatic Transmission 3 Gear Transmission 5 Hydraulic Circuit 11 1st Speed Solenoid Valve 33 1st Speed Clutch 34 2nd Speed Clutch 40 Controller

Claims (5)

[Claims] 1. An automatic vehicle for changing the rotational speed of an input shaft toward the post-shift synchronous rotational speed by engaging the second frictional engaging means while releasing the engagement of the first frictional engaging means. In the transmission gear shift control method, when it is detected that the rotation speed of the input shaft is synchronized with the synchronized rotation speed after the gear shift, the working oil pressure of the second friction engagement means is set to a predetermined pressure, and then the working oil pressure is set to the predetermined value. A shift control method for an automatic transmission for a vehicle, comprising gradually increasing from the predetermined pressure. 2. The shift control method for an automatic transmission for a vehicle according to claim 1, wherein the working hydraulic pressure is gradually increased after the predetermined pressure is continued for a first predetermined time. 3. The operating oil pressure is maintained for a second predetermined time,
3. The shift control method for an automatic transmission for a vehicle according to claim 1, wherein the maximum hydraulic pressure is supplied to the second friction engagement means after the hydraulic pressure is gradually increased at a constant rate. 4. The predetermined pressure is determined according to a load state of a vehicle engine.
5. A shift control method for an automatic transmission for a vehicle according to any one of 1. 5. The shift control method for a vehicle automatic transmission according to claim 1, wherein the predetermined pressure is determined according to an input shaft torque.