JPH0425663A - Shift control method of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To make feedback control performable in an optimum way by finding an input revolution, equalizing the input revolution of an input shaft detected perunit time, and calculating an input revolution variation from this input revolution. CONSTITUTION:When an input revolution NT is read, this input revolution NT is made so as to be equalized. If the input revolution NT is equalized and found out like this, even if in the case where a variation occurs in the input revolution NT due to torsional vibration or the like, an input revolution variation NT is calculated on the basis of the equalized input revolution NT, through which this input revolution variation NT is smoothed. The input revolution variation NT smoothed like this serves as such that is accurately reflected by the actual input revolution variation, so that a duty factor D is properly controllable on the basis of this input revolution variation NT, therefore the feedback control is performable in a highly accurate manner.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for controlling a shift in an automatic transmission for a vehicle, and particularly relates to an automatic shift for a vehicle in which the shift control is performed based on feedback control. This invention relates to a method for controlling the speed change of an aircraft.

(Prior art) An automatic transmission for a vehicle has an input shaft that receives the rotational force from the engine, an output shaft that outputs driving force to the drive wheels, and is arranged between the input shaft and the output shaft. A rotating element such as a rotating drum or a gear, and a friction engagement device such as a clutch or a brake that cooperates with the rotating element to control the rotation of the rotating element. Here, the frictional engagement device is
This friction engagement device is hydraulically actuated, and is operated by receiving pressure fluid whose pressure is controlled by duty control based on a gear change command according to the vehicle's driving condition. In a transmission, a rotating element between an input shaft and an output shaft is appropriately selected so that a desired speed change is automatically performed.

Regarding the shift operation in the above-mentioned automatic transmission, it is required to suppress the shift shock during the shift operation as much as possible, to perform the shift operation smoothly, and to shorten the time required for the shift operation. There is. One method for meeting such demands is to feedback-control the operation of the friction engagement device so that the input rotation rate of change of the input shaft follows the target rotation rate of change from an appropriate point during the gear shifting operation. There is. In this feedback control, the operation of the frictional engagement device is specifically controlled by the operating pressure supplied to the frictional engagement device, that is, the duty rate corresponding to the operating pressure.

(Problem to be Solved by the Invention) By the way, when implementing the feedback control described above, the input rotation rate of change is calculated based on the input rotation speed of the input shaft, but here, the input rotation speed is ,
The value fluctuates due to torsional vibrations caused by rotational fluctuations of the engine itself and sudden torque fluctuations. Therefore, if the input rotation change rate is calculated based on the actually detected input rotation speed, the above-mentioned fluctuation in the input rotation speed will be undesirably reflected in the input rotation change rate, and the calculated input rotation change The rate will deviate greatly from the actual input rotation rate of change. As a result, even if the duty rate is calculated based on the above input rotation rate of change,
This duty rate value may not match the actual situation, and there is a possibility that feedback control may not be optimally implemented.

This invention was made based on the above-mentioned circumstances, and
The purpose of this is to be able to perform feedback control optimally to accurately calculate the duty rate, and based on this duty rate, to appropriately control the hydraulic pressure to be supplied to the friction engagement device. An object of the present invention is to provide a speed change control method for an automatic transmission.

(Means for Solving the Problems) This invention cooperates with a rotating element between an input shaft into which rotational force from an engine is input and an output shaft that transmits driving force to the driving wheels. It is equipped with a hydraulically actuated friction engagement device that controls rotation, and by supplying duty-controlled operating pressure to this friction engagement device and operating the friction engagement device, the input shaft is rotated through the rotating element. The speed change control method of the present invention is applied to a vehicle automatic transmission that performs a speed change operation between the input shaft and the output shaft. The duty rate that determines the operating pressure to the frictional engagement device is feedback-controlled so that the rotational change rate of the input shaft follows the target rotational change rate from the time when the value of . The average input rotation speed per unit time is determined from the rotation speed, and the rotation change rate of the human power shaft is calculated based on this average input rotation speed.

(Operation) According to the speed change control method of the present invention, during feedback control, when determining the input rotation speed of the input shaft, the average input rotation speed per unit time at the input rotation speed is determined, and this average input rotation speed is Since the rotational change rate of the input shaft is calculated from the number, the calculated rotational change rate is not adversely affected by torsional vibration of the input shaft.

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

FIG. 1 shows an example of an automatic transmission for a vehicle. In the figure, reference numeral 2 indicates an engine 2 that serves as a power source for the vehicle, and a crankshaft 4 of this engine 2 is directly connected to a pump 8 of a torque converter 6.

The torque converter 6 is connected to a case 16 via a pump 8, a turbine lO, a stator 12, and a one-way clutch 14.
is combined with The stator 12 is allowed to rotate in the same direction as the crankshaft 4 by a one-way clutch 14, but is prevented from rotating in the opposite direction.

The torque transmitted to the turbine 10 is transmitted to an input shaft 20, and from the input shaft 20 to a gear transmission 22 disposed at the rear of the input shaft 20. Here, the gear transmission 22 has a structure that achieves four forward speeds and one reverse speed.

The gear transmission 22 includes three sets of clutches 24, 26° 28
, two sets of brakes 30 and 32, - set of one-way clutches 34, and - set of Ravigneau-type planetary gear mechanism 36.

The planetary gear mechanism 36 includes a ring gear 38, a long pinion gear 40, a short pinion gear 42, and a carrier 48 that rotatably supports both pinion gears 40 and 42 and is also rotatable. ring gear 38
is connected to the output shaft 50, and the front sun gear 44 is connected to the input shaft 20 via the kickdown drum 52 and the front clutch 24. On the other hand, the rear clutch 46 is connected to the input shaft 20 via the rear clutch 26. And career 48
is connected to the case 16 via a low reverse brake 32 and a one-way clutch 34 which are arranged functionally in parallel, and via a 4-speed clutch 28 arranged at the rear end of the transmission 22. and is connected to the input shaft 20.

Here, the kickdown drum 52 can be fixedly connected to the case 16 by the kickdown brake 30.

The torque transmitted via the planetary gear mechanism 36 is transmitted to an output gear 60 fixed to the output shaft 50 so as to rotate integrally with the output shaft 50.
The output gear is transmitted from the output gear 0 to the driven gear 64 via the idle gear 62, and further transmitted to the drive shaft of the driving wheels via the transfer shaft 66 and helical gear 68 fixed to the driven gear 64. 70 is transmitted to a differential gear device 72 to which the signal 70 is connected.

Each of the above-mentioned clutches and brakes, which are frictional engagement elements, is included in a frictional engagement device equipped with an engagement piston device or a servo device, and this frictional engagement device is connected to the pump 8 of the torque converter 6. By being connected, they are operated by hydraulic pressure generated by an oil pump (not shown) driven by the engine 2. This hydraulic pressure is selectively supplied to each clutch and brake according to various operating conditions by a hydraulic control device, which will be described later.
Depending on the combination of brake operations, four forward speeds and one reverse speed are achieved, as shown in Table 1. In Table 1, the ○ mark indicates the engagement state of each clutch or brake, and the * mark indicates that the carrier 48 is activated by the action of the one-way clutch 34 immediately before the low reverse brake 32 is engaged during gear shifting. indicates that the rotation is stopped.

(Left space below) Table Next, an electro-hydraulic control device for achieving the gears shown in Table 1 in the gear transmission 22 shown in FIG. 1 will be described based on FIG. 2.

Note that FIG. 2 shows only the hydraulic control elements that operate the front clutch 24 and kickdown brake 30, respectively. Since the overall structure and operation of this electro-hydraulic control device is already known from Japanese Patent Laid-Open No. 58-46258, etc., explanations of other hydraulic control elements of the brake and clutch will be omitted.

The kickdown servo 31 is a reciprocating hydraulic actuator that controls the operation of the kickdown brake 30.
A housing defining a stepped cylinder hole 80, a stepped piston 59 slidably fitted into the stepped cylinder hole 80, and a piston rod, ie, an actuator rod, extending from the piston 59 to the outside of the housing. 79, and the tip of the actuator rod 79 can abut and engage with the kickdown brake 30, that is, the brake shoe wrapped around the kickdown drum 52. . and,
The piston 59 has first and second pressure chambers 82 and 83 defined in a stepped cylinder hole 80, and as is clear from FIG. and the stepped surface of the stepped cylinder hole 80.

An I-2 shift valve 33 is connected to the first pressure chamber 8I of the kickdown servo 31 via an oil passage 35, and this 1-2 shift valve 33 is further connected to the first pressure chamber 8I via an oil passage 41. The transmission control valve 37 is also connected to the transmission control valve 37.

Further, an oil passage 83 is branched from the middle of the oil passage 35, and this oil passage 83 is connected to a 2-3 shift valve 84. This 2-3 shift valve 84 is further connected to oil passages 85 and 86 which are branched into two, and one oil passage 85 of these two oil passages is connected to the second pressure of the kickdown servo 31. It is connected to the chamber 82, and the other oil passage 8
6 is connected to the aforementioned front clutch 24. Note that in FIG. 2, the front clutch 24 is only schematically illustrated.

Here, the l-2 shift valve 33 and the 2-3 shift valve 84 are spool-type on-off valves that are opened and closed by pressure supplied to their operation control ports 87.88. The pressure is specifically guided from a switching valve (not shown).

For example, in the 1-speed gear position, the spool 55 of the 1-2 shift valve 33 does not receive switching pressure through its operation control port 87, unlike the case shown in FIG. It is in a displaced state. Therefore, in this case, the oil passage 35 communicates with the oil drain port EX of the 1-2 shift valve 33, and thereby the first oil passage of the kickdown servo 31
Pressure chamber 81 will be connected to the low pressure side. As a result, the piston 59 of the kickdown servo 31 is returned to the right in FIG. The engagement has been released.

Further, at this time, switching pressure is not supplied to the 2-3 shift valve 84 through its operation control port 88, so the spool 89 is displaced to the left end as shown in FIG. be. Therefore, in this case, the oil passage 86 leading to the front clutch 24 is connected to the 2-3 shift valve 8.
The front clutch 24 is connected to the low pressure side through the oil drain port 90 of No. 4, and thereby the front clutch 24 is disengaged. In this case, since the oil passages 85 and 86 are always in communication, the second pressure chamber 80 in the kickdown servo 31 is also connected to the low pressure side.

Further, in the second gear, the 1-2 shift valve 33 is switched to the illustrated switching position, and the 1-2 shift valve 33 is switched to the illustrated switching position.
Shift valve 84 has also been switched to the position shown. Therefore, in this case, by supplying pressure fluid to the first pressure chamber 81 of the kickdown servo 31 through the oil passage 41°35, the piston 59, that is, the actuator rod 79 moves to the left and kicks. The down brake 30 is engaged, and the pressure fluid in the front clutch 24 can be discharged through the oil passage 86 and the oil drain port 90, thereby disengaging the front clutch 24. .

Further, in the third gear, the 1-2 shift valve 33 remains in the illustrated switching position;
The shift valve 84 is in the switching position with its spool moved to the right, and thereby the oil passage 83 and the oil passages 85, 86
is communicated with through the 2-3 shift valve 84, and its oil drain port 90 is closed. in this case,
(1) Pressure fluid supplied to the oil passage 83 through the 2-2 shift valve 33 is supplied to the front clutch 24 through the 2-3 shift valve 84 and through the oil passage 86.
This brings the front clutch 24 into an engaged state.

On the other hand, in the kickdown servo 31, the oil passages 86, 85 are always in communication, so the pressure fluid supplied to the front clutch 24 is also supplied to its second pressure chamber 82, and At the same time, the same pressure liquid is also supplied to the first pressure chamber 8I through the oil passage 35. In this case, since the piston 59 of the kickdown servo 31 is a stepped piston as described above, due to the difference in the pressure receiving area at both ends, the piston 59 is connected to the actuator rod 7.
9 to the right, thereby disengaging the kickdown brake 30.

Furthermore, when the gear stage is shifted from 3rd speed to 2nd speed, each of the 1-2 shift valve 33 and the 2-3 shift valve 84 is at the switching position shown in the figure, and in this case, the kickdown servo 31 When the pressure fluid is supplied to the first pressure chamber 81, the piston 59, that is, the actuator rod 79 is displaced in the direction of engaging the kickdown brake 30, while the front clutch 24 Oil line 86.2-3 shift valve 84 and oil drain port 9
When the pressure fluid is released through 0, the engagement is released, but at this time, the front clutch 24
Disengagement is performed by the kickdown servo 31 as described later.
When the piston 59 of is displaced, its second pressure chamber 82
It is controlled by the back pressure generated by the

Therefore, in order to generate appropriate back pressure in the second pressure chamber 82, a predetermined throttle 91 is provided in the oil drain port 90 of the 2-3 shift valve 84, and 8
4 is also provided with a predetermined throttle 92.

As shown in FIG. 2, the above-mentioned speed change control valve 37 has
An oil passage 61 and an oil passage 63 are connected to the left end thereof. The oil passage 61 is connected to the oil pump described above, and there are
A solenoid valve 67 is inserted to open and close this oil passage 61 and to control the pressure of the pressure fluid supplied through the speed change control valve 37. This solenoid valve 67 is electrically connected to an electronic control unit (ECU) 65, and this electronic control unit 65 controls the switching operation of the solenoid valve 67 through duty control. Further, the oil passage 63 is also supplied with working oil pressure regulated to a predetermined pressure from the aforementioned oil pump. The pressure fluid in the oil passage 61 is discharged to the low pressure side via the electromagnetic valve 67 which is opened and closed according to the duty rate, and therefore, the hydraulic pressure according to the duty rate acts on the left end surface of the spool 69 of the speed change control valve 37. I will do it. As a result, the speed change control valve 37 regulates the oil pressure from the oil passage 63, and the oil pressure P shown by the broken line in FIG.
KD will be generated in the oil passage 41.

The electronic control device 65 not only controls the opening and closing of the solenoid valve 67 but also has a built-in shift command output device that outputs a shift command based on the driving state of the vehicle. In order to detect the driving state of the vehicle, signals from various sensors or detection devices are input.

For example, these sensors or detection devices include an engine rotation speed sensor that detects the rotation speed of the engine 2, a throttle valve opening sensor 103 that detects the throttle valve opening θ of the engine 2, and a throttle valve opening sensor 103 that detects the rotation speed NT of the input shaft 20. The input shaft speed sensor 101 detects the rotation speed NO of the output shaft 50 corresponding to the vehicle speed.
an output shaft speed sensor 144 of the driven gear 64 provided to detect the temperature of the lubricating oil;
There are select lever selection position detection switches, auxiliary switch selection position detection devices, etc.

Further, in this embodiment, a signal from a kickdown switch 93 built into the kickdown servo 31 is also input to the electronic control device 65. This kickdown switch 93 is configured such that the piston 59 is moved to the left in FIG. When moved to the reference position, a signal is output to the electronic control unit 65.

In FIG. 2, among the sensors and detection devices input to the electronic control device 65, the input shaft speed sensor 101. Throttle valve opening sensor 103, output shaft speed sensor 144
, and only the kickdown switch 93 are shown.

Next, the downshift operation from third speed to second speed performed by the electronic control device 65 described above will be described in detail with reference to FIG. 3 and subsequent figures.

3-2 Shift Down Routine First, the main 3 shift down routine shown in FIGS. 3A and 3B.
-2 When the downshift routine is performed, the gear stage of the automatic transmission is in 3rd gear, and therefore, as is clear from Table 1 above, the kickdown brake 31 is in a disengaged state. Yes, on the other hand, the front clutch 24
are in an engaged state.

This routine is performed for a predetermined control cycle, e.g.
It is repeated in the control cycle every 5ec, and the 3rd A
In the figure, in step Sl, from the gear change command output device 3-2
It is determined whether a shift command has been generated or not. Here, the gear change command output device is 3-2 indicated by the broken line in FIG.
Based on the shift line, a 3-2 shift command is output in consideration of vehicle speed and throttle valve opening. In addition, in FIG. 9, the solid line indicates the 2-3 shift line.

If the determination in step S1 is negative (No), the process proceeds to step Sll shown in FIG. 3B, and this step
At 11, the duty rate of the solenoid valve 67 is set to 0, and the timer TD is reset to 0, and the process returns to step S1.

When the determination in step Sl becomes positive (Yes), in step S2, the input shaft speed sensor 101
The rotation speed NT of the output shaft and the rotation speed NO of the output shaft are read from the output shaft speed sensor 144.

In the next step S3, it is determined whether a signal is output from the kickdown switch (KD switch) 93, that is, whether the KD switch 93 is turned on. Here, immediately after the routine from step S1 is executed, the kickdown servo 31 has not yet been activated, so the determination here is negative, and step S4
After the integral pressure value AP is set to 0, step S
Proceed to step 5. The integral pressure value AP is calculated in the stroke amount determination routine S5, which is executed when the determination in step S3 is positive.

Step S4 or Step S5 leads to Step S6, where the input rotation speed NT of the input shaft 20 is 1.2.
It is determined whether or not it is greater than or equal to NO.

Here, NO is the output rotation speed of the output shaft 50.

Immediately after starting this routine, the determination in step S6 is negative, so the process proceeds to step S7, where the duty rate of the solenoid valve 67 is controlled by open loop control.

On the other hand, if the determination in step S6 is positive, the third
Step S8 shown in Figure B is reached, where it is determined whether the flags Fj and GS are set to 1 or not. Here, the flag FLGS is set to the kickdown servo 3 in the stroke amount determination routine of step S5 described above.
It is set to 1 when one actuator rod 79 reaches its maximum stroke. Therefore, in this case, since the determination is still negative, step S9 is bypassed and the process proceeds to step SIO.

In step SIO, it is determined whether the value of a timer TD, which is set when step S9 is executed and measures the elapsed time, is equal to or longer than a predetermined time XTD.
Since step S9 has not been performed yet, the determination is negative and the process advances to step S12.
In step 12, the duty rate of the solenoid valve 67 is controlled based on feedback control.

Note that step S9 is executed only when the flag FLGS is set to 1 in the stroke amount determination routine in step S5 after the kickdown switch 93 is turned on.

Furthermore, as is clear from the flowcharts in FIGS. 3A and 3B, the open loop control routine in step S7 is executed immediately after the 3-2 downshift routine is started, and until the determination in step S6 is made. The feedback control routine in step S12 is then carried out following the open loop control routine. However, after this, the feedback control routine starts when the actuator rod 79 reaches its maximum stroke, and after the predetermined time Finish, 3-
2nd shift will be completed.

Open Loop Control Routine The open loop control routine described above is shown in detail in FIGS. 4A to 4C. In this routine, in step 5101, the value of timer TSI is set to XSI (for example, 0. 1 sec) is reached. Note that this timer TSI is, for example, a herba timer built into the electronic control unit 65, and is activated when the 3-2 shift command is output, and the time measured by this timer TSI is the time when the 3-2 shift command is output. This is the elapsed time since the In this case, since the value of timer TSI has not yet reached the predetermined time XSI, step S
The determination in step S101 is negative, and step S102 is executed. In this step, the duty rate of the solenoid valve 67 is set to DUO, and each flag FLGS
Each of flags 1 to FLGS3 is reset to 0.

Therefore, as shown in FIG. 10, when the 3-2 shift command is output, the duty rate is set to DuO instead of 0, and this state continues until the predetermined time XSI has elapsed. be done.

When the duty rate of the solenoid valve 67 is set in this way, hydraulic pressure PKD having a pressure value corresponding to the duty rate DuO is supplied to the first pressure chamber 81 of the kickdown servo 31 through the oil passages 41 and 35. As a result, the pressure within the first pressure chamber 81 is reduced to a pressure corresponding to the duty rate DUO. However, since this pressure is sufficient to displace the piston 59 to the left in FIG. 2 against the spring force of the compression coil spring 57, the actuator rod 79 also moves in conjunction with the piston 59. The kickdown brake 30 is operated in a direction to tighten the kickdown drum 52.

Then, when the set predetermined time XSI has elapsed, the determination in step S lot becomes positive, so step 510
3 is executed, the value of timer TSI is reset, and in step 5104, input rotation speed NT becomes NTO+ΔN1.
It is determined whether or not the value is greater than or equal to the value. Here, NTO indicates the input rotation speed of the input shaft 20 at the time when the 3-2 shift command is output, and ΔN1 is a predetermined value (for example, 35
rpm). In this case, since the input rotation speed NT has not changed from NTO yet, the determination in step 5104 is negative, and the next step 5105 is executed, but the flag FLGS 1 remains reset to 0. Since there is, the process advances to step 5106.

In this step 8106, the duty rate is set to DUI, which is a larger value than DuO, and at this time, the flag FLGS 1 is set to 1.

Therefore, in this case, the value of the oil pressure PKD supplied to the first pressure chamber 81 of the kickdown servo 31 is reduced due to the increase in the duty rate.

On the other hand, if step 5106 is executed on -1, the determination at step 5105 will be positive in the next execution cycle, so step 5107 will be executed thereafter. In this step 5107, the current duty rate is changed by a predetermined amount Δ every time the execution cycle is repeated.
DI is increased. Therefore, as shown in FIG. 10, the duty rate is changed to gradually increase from Dul, thereby causing the kickdown servo 3
The pressure in the first pressure chamber 81 is also gradually reduced.

When the duty rate is controlled as described above, the piston 59 of the kickdown servo 31 is first moved for a predetermined time XSI with a relatively high oil pressure PKD, and then
The speed of movement is first rapidly reduced and then further gradually reduced. By controlling the stroke speed of the piston 59 in this manner, an increase in back pressure within the second pressure chamber 82 can be suppressed. As a result, the second
Since the back pressure of the pressure chamber 82 does not act on the front clutch 24 through the oil passages 85 and 86 and has no adverse effect,
The pressure fluid is effectively discharged from the front clutch 24 through the oil passage 86.2-3 shift valve 84 and the oil drain port 90, and the engagement of the front clutch 24 begins to release smoothly. It turns out. Furthermore, since the operation of the front clutch 24 can be controlled by controlling the back pressure in the second pressure chamber 82 in this way, such back pressure control
It can be used to control the input rotation speed of the input shaft 20 during feedback control, which will be described later.

As described above, when the front clutch 24 starts to disengage, that is, when the front clutch 24 starts to slip, the input rotational speed NT of the input shaft 20 starts to increase from this point on. The starting point of increase in the input rotational speed NT is indicated by the symbol U in FIG. 10, and from this point on, the shift operation from 3rd speed to 2nd speed is actually started.

After this, when the amount of increase in the input rotation speed NT reaches ΔN1,
In the open loop control routine, step 51
The determination in step 04 is positive, and the next step 8108 is executed. In this step, it is determined whether the value of timer TS2 has reached a predetermined time XS2. This timer T
S2 starts its operation when the determination result in step 5104 changes from negative to positive. Here, when step 5108 is executed for the first time, the determination is negative, so step 5109 is executed.

In this step 5109, a determination is made regarding the flag FLGS2, but since the determination here is still negative,
Step 5110 is performed.

In step 5LIO, the duty rate is decreased by a predetermined amount ΔD5 (for example, 5%) from the current value, and
Flag FLGS2 is set to 1.

Therefore, after the input rotation speed NT is 3-2 and the shift command is output,
When the duty rate increases by ΔNl, the duty rate becomes
As shown in the figure, the oil pressure PKD supplied to the first pressure chamber 81 of the kickdown servo 31 becomes higher because it is decreased by ΔD5 from its current value. This results in
Since the back pressure in the second pressure chamber 82 is also increased, disengagement of the front clutch 24 is suppressed, and the input rotation speed NT of the input shaft 20 is not increased suddenly.

Furthermore, after step 5IIO is executed on -1st, the determination in step 5109 will be positive in the next execution cycle, so after this step 5107
is carried out again, and therefore, as shown in FIG. 1θ, the duty rate begins to gradually increase, and in conjunction with this, the input rotation speed NT also gradually increases.

Then, when the value of the timer TS2 in step 3108 reaches the predetermined time XS2 or more, the determination here becomes positive, so in this case, step 5ill is executed. At this step, the determination is still negative, so step 8112 is executed. Here, the duty rate is
A predetermined value ΔD5 is added to the current value, and the flag F
1 is set in LGS3. Also, step 5112
Once executed, the determination in step 5ill will be positive in the next execution cycle, so step 5113 will be executed thereafter, and as a result,
The duty rate is calculated as follows: Each time the execution cycle is repeated,
It will be decreased by a predetermined amount ΔD2. Therefore, the first
As shown in FIG. 0, after the determination in step 5108 becomes positive, the duty rate is increased by ΔD5 and then decreased by ΔD2. As a result, the input rotation speed NT will be gradually increased.

When the duty rate of the solenoid valve 67 is controlled as described above, the piston 5 in the kickdown servo 31
By making effective use of the stroke time of step 9 and controlling the stroke speed, that is, the back pressure of the second pressure chamber 82, the engagement state of the front clutch 24 can be finely controlled and the input rotation speed NT can be increased. can be achieved as desired.

Stroke Amount Determination Routine When the open loop control routine as described above is executed, the actuator rod 79 of the kickdown servo 31, that is, its piston 59 is gradually displaced to the left in FIG. 59 has been displaced to the above-mentioned reference position, the determination at step S3 in the 3-2 shift down routine becomes positive, and from this point on, the stroke amount determination routine is executed.

This stroke amount determination routine is shown in FIG. 5, and in this routine, first, step 5201
is carried out, and in this step, the above-mentioned integrated pressure value A
By adding the corrected hydraulic pressure P KDN corresponding to the current duty rate of the solenoid valve 67 to P, the integral pressure value A
P is updated to a new value. Here, the corrected oil pressure value PKD
N is determined from the correction characteristic shown in the solid line obtained by correcting the characteristic shown in the broken line in FIG. This correction characteristic is
In the area where the duty rate is small, the actual oil pressure value PKD
The corrected oil pressure value P KDn is set to be lower than the actual oil pressure value PKD, and conversely, in a region where the duty ratio is large, the corrected oil pressure value P KDN is set to be higher than the actual oil pressure value PKD.

Proceeding to the next step 5202, this step 5202
Then, it is determined whether the integrated pressure value AP has reached a predetermined value XAP or more. Here, the predetermined value XAP means that when the duty rate is continued to be set to the reference duty rate DUS shown in FIG. In this embodiment, the first pressure chamber 81 of the kickdown servo 31 is
This corresponds to the integral value obtained by adding the reference oil pressure P KDS supplied to the PKDS every 20 Insec. Then, the oil pressure supplied to the first pressure chamber 81 of the kickdown servo 31 is the reference oil pressure P.
If it is different from KDS, the stroke amount can be detected accurately by correcting this oil pressure to the corrected oil pressure value PKDN shown by the solid line in FIG. This correction is for correcting the leakage of hydraulic oil in the first pressure chamber 81 of the kickdown servo 31. In other words, as the oil pressure becomes higher, the amount of leakage becomes larger and the stroke amount cannot be detected accurately.
is set to a value smaller than .

Therefore, in order to correct the above-mentioned problem by correcting the characteristic indicated by the broken line in FIG. By integrating and finding
The integral pressure value AP can be made to correspond accurately to the stroke amount of the kickdown servo 31. Therefore, by comparing this integrated pressure value AP and the predetermined value XAP in step 5202, it is possible to accurately detect whether the piston 59, that is, the actuator rod 79 has reached its maximum stroke. . In other words, it is possible to accurately detect the point in time when the shift from third speed to second speed is substantially completed.

If the determination in step 5202 is negative, that is, if the actuator rod 79 has not yet reached its maximum stroke, the process proceeds to step 5203, where the flag FLGS is set to 0. On the other hand, if the determination in step 5202 is positive and the actuator rod 79 has reached its maximum stroke, step 5204 is executed and the flag FLGS is set to 1.
will be set. That is, when the execution cycle of the 3-2 shift down routine is repeated, the stroke amount determination routine is executed after the kick down switch 93 is turned on, and the actuator rod 79 reaches its maximum stroke. It is possible to detect whether the limit has been reached or not based on the value of the flag FLGS. still,
The point at which actuator rod 79 reaches its maximum stroke is indicated by SE in FIG.

Feedback Control Routine When the open loop control routine described above is completed based on the determination result at step S6, a feedback control routine is executed, which is shown in FIGS. 6A and 6B.

In this routine, first, in step 5301, it is determined whether this feedback control is being performed for the first time. That is, in repeating the execution cycle, it is determined whether step 5301 is executed for the first time. If the determination here is positive, step 5302
will be implemented.

In this step 5302, the duty rate is DU2
It is determined from +ΔDa. Here, DU2 indicates a reference duty rate at the start of feedback control, and ΔDa indicates a correction amount obtained by learning, which will be described later.

Further, in step 5302, various flags FLGFI
, FLGDI, FLGD2. Each FLGL is 0
will be reset to

If the determination in step 5301 is negative, the next step 5
At 303, the input rotation speed NT of the input shaft 20 is 1.4.
5NO (NO is the output rotational speed of the output shaft 50) or not is determined. If the determination here is negative, in the next step 5304, the input rotational speed NT is further determined. It is determined whether or not it has reached 1.45NO-ΔN2 or more. Here, ΔN2 is set to, for example, 400 rpm. If the determination here is also negative, that is,
Immediately after the input rotational speed NT reaches 1 or 2 NO or more, which is the starting condition for feedback control, the process proceeds to step 5305.

In this step 5305, ΔNil is set as the target rotational change rate ΔNi of the input shaft 20, and then, after a duty rate calculation routine is executed in step 5306, in the next step 5307, Whether it is in the learning area of the correction amount ΔDa mentioned above, that is, the correction amount Δ
It is determined whether learning of Da should be performed. Here, the conditions for determining whether or not it is in the learning area are, for example, that the temperature of the hydraulic oil supplied to the kickdown servo 31 is 60°C, and that the output rotation speed NO of the output shaft 50 is 1300 rpm.
m to 3000 rpm.

If the determination in step 5307 is positive, a learning initial value calculation routine for the correction amount ΔDa is executed in step 5308, but if the determination in step 5307 is negative, step 5308 is bypassed. become.

On the other hand, after the feedback control is started, if the determination in step 5304 becomes positive as the input rotation speed NT increases, step 5309 is executed, and here, it is determined whether or not the flag FLGFI is set to 1. It is determined. In this case, since the flag FLGFI is still reset to 0, the determination here is negative, and step 5310 is executed.

In step 5310, the target rotational change rate ΔNi of the input shaft 20 is calculated based on the following equation.

ΔNi = (ΔNil+ΔN12)/2 where,
ΔNi2 takes a smaller value than ΔNil.

Further, in step 5310, the flag FLGFI is set to 1. When the target rotational change rates ΔNil and ΔNi2 change significantly, control stability is improved by setting the intermediate value, which is the average value, as the target rotational change rate and performing feedback control using that value, as described above. do.

Therefore, after step 5310 has been executed once, the determination in step 5309 will be positive in the next execution cycle, so in this case, step 5311 will be executed and the target rotational change rate ΔNi of the input shaft 20 will be ΔNi2 is set to . After this, steps after step 5306 are performed.

Further, when the input rotational speed NT of the input shaft 20 further increases and the determination at step 5303 becomes positive, step 312 is executed. In step 5312, the operation of timer TFI is started, and step 5303
When the determination becomes positive, that is, when the input rotation speed NT is 1.
The elapsed time from the time when 45 NO is reached is measured, and it is determined whether or not the value of the timer TFI has exceeded the predetermined time XFI. If the determination here is negative, in step 5313, the target rotational change rate Δ of the input shaft 20 is determined.
-ΔNi4, which is a negative value, is set for Ni. On the other hand, if the determination is positive, in step 5314, the target rotational change rate ΔNi of the input shaft 20 is set to -ΔNi3, which is also a negative value. be done.

Here, -ΔNi3 is an even smaller value than -ΔNi4.

After this, the steps after step 5306 described above are performed. That is, as is clear from the above description, in the feedback control routine, first, the target rotational change rate ΔNi is determined according to the value of the input rotational speed NT of the input shaft 20.
After this is set, a duty rate calculation routine and a learning initial value calculation routine are executed.

The target rotational change rate ΔNi determined as described above is the 10th
As is clear from the figure, as the input rotation speed NT increases from 1.2NO, it is gradually decreased, and when the input rotation speed NT exceeds 1.45NO, the final target input rotation speed is reached. As you get closer to a certain 1,5 ONo.
The target rotation rate of change ΔNi is set to a negative value that increases stepwise. Note that the intermediate value set between ΔNil and ΔNi2 is set only for one execution cycle time (20 m5ec).

Duty Rate D Routine Details of the duty rate calculation routine in step 5306 described above are shown in FIGS. 7A, 7B, and 7C. In this routine, first, step 54
01, the deviation En between the target rotational change rate ΔNi of the input shaft 20 and the actual input rotational change rate and the amount of change ΔEn of this deviation En are calculated based on the following equation.

En=ΔNi −(ΔNT)n ΔEn =En −En−1 Here, ΔNT is the current input rotation speed NTn and the previous N
It shows the difference from Tn-1, and therefore, ΔNT is ΔNT = NTn-NTn-1. Similarly, when E n-1 is expressed as a formula, En
−1=ΔNi−(ΔNT)n−1. Therefore, when step 5401 is executed, the previously determined values of NTn-1 and E n-1 are
5 is stored in memory.

In the next step 5402, the integral gain (Di)n in feedback control is calculated based on the following equation.

(Di) n = (Di) n-1+KI-E
where (Di) n-1 indicates the previous value, and Kl is the reference integral gain. Also,
a is a coefficient for reducing the integral gain (Di)n by 0.5% every execution cycle time (20m5ec),
In the oil pressure supplied to the first pressure chamber 81 of the kickdown servo 31, the slope of the pressure change is -0.5%720
This means that it is m5ec. b is input shaft 2
When the input rotation rate of change ΔNT at 0 becomes a negative value, the integral gain (I) n is set to 1 for each execution cycle time.
This is a coefficient for increasing the response speed by %.

Note that when the input viewpoint change rate ΔNT is a negative value, the target input rotation change rate ΔNi is set to zero.

In the next step 5403, the duty ratio is calculated from (Di)n based on the following equation.

D=(Di)n×KP−En×KD・ΔEnwhere, K
P indicates a proportional gain, and KD indicates a differential gain.

When the duty rate is determined in step 5403, the process advances to the next step 5404, where it is determined whether the flag FLGDI is 1 or not. In this case, since the flag FLGDI remains reset to 0, the process advances to step 5405. This step is
It is determined whether the flag FLGD2 is 1 or not, but here as well, since the determination is negative, step 8406 is executed.

In step 8406, the integral pressure value AP calculated in the stroke amount determination routine described above is 0.7XAP.
It is determined whether or not the above value has been reached.

In other words, here, in the kickdown servo 31,
It is determined whether the current stroke amount of the actuator rod 79 has reached 70% or more of the maximum stroke. If the determination here is negative, the next execution cycle is executed as is, and the already determined duty rate is used.

However, if the determination in step 8406 is positive, the process proceeds to the next step 5407, and in this step, the current input rotation speed NT of the input shaft 20 is changed for a predetermined period of time Δt(
For example, after a period of 0.16 sec), it is predicted whether or not the final target input rotation speed of 1.5 ONO will be reached. That is, this prediction is made by determining whether or not the following equation is satisfied.

(NT+ΔNT·Δt)≧1.5ONO Here, the predetermined time Δt represents the time required for the stroke amount of the actuator rod 79 to reach the maximum stroke after reaching 70% or more of the maximum stroke. This predetermined time Δt is experimentally set to a predetermined value.

If the determination in step 5407 is positive, that is, before the actuator rod 79 reaches its maximum stroke,
1, 5 where the input rotation speed NT is the final target input rotation speed
If it is predicted that ONO will be reached, step 840
The process advances to step 8, where the flag FLGDI is set to 1. Once the flag FLGDI is set to 1 in this way, the determination at step 5404 will always be positive in the next execution cycle, so steps after step 5405 will no longer be executed.

On the other hand, if the determination in step 5407 is negative, that is, as shown in FIG. Then, actuator rod 79
If it is predicted that the predicted input rotational speed NTY has not reached 1.5 ONO even though has already reached the maximum stroke, the process proceeds to step 5409, where a predetermined amount ΔD4 ( For example, 4%) is added, and the flag FLGD2 is set to 1.

Therefore, in subsequent execution cycles, the flag FLGDI
Since the flag FLGD2 is set to 0 and the flag FLGD2 is set to 1, step S410 is executed without executing the steps after step 5406 shown in FIG. 7B. That is, step 5407 calculates the integral pressure value AP
It is performed only once when the stroke reaches 70% or more of the maximum stroke.

In step 5410, the input rotation speed NT is 165 ONO.
It is determined whether or not this has been reached, and if the determination here is negative, the next execution cycle is simply executed. That is, in this case, the duty rate is maintained increased by the predetermined amount ΔD4. However, if the determination at step 5410 is positive, then step 54
11 is carried out, and here, a predetermined amount Δ is added to the duty rate.
D4 is decreased and the duty rate is returned to its original value,
Then, the flag FLGDI is set to 1.

Therefore, as shown in FIG. 12, when the duty ratio is increased by a predetermined amount ΔD4, this state is maintained until the input rotational speed NT reaches 1.5ONo. In addition, when the determination in step 5407 is negative in this way, the duty rate is increased to promote disengagement of the front clutch 24 and to hasten the increase in the input rotational speed NT. This ensures that the input rotational speed NT reaches its final target input rotational speed of 1.5NO before the actuator rod 79 reaches its maximum stroke, ie at the SE time.

μ Value Routine In the feedback control routine, after the duty rate calculation routine is executed as described above, step 5
A learning initial value calculation routine is executed through step 307, and this routine is shown in detail in FIGS. 8A to 8D.

First, in step 5501, the flag F
It is determined whether 1 is set in LGL,
At this point, the flag FLGL is still reset to 0, so the determination here is negative, and the process advances to the next step 5502 and then step 5503. In these steps, it is determined in step 5502 whether the input rotational speed NT has reached 1.45NO or more;
Further, in step 5503, the input rotation speed NT is 1.4.
It is determined whether the number is 5NO-682 or more. Here, if the input rotation speed NT has not been increased enough to satisfy the condition of step 5503, that is, if the input rotation speed NT is still low, the determinations at steps 5502 and 5503 will be negative. Next, step 5504 is performed.

In this step 5504, the input rotation change rate (ΔNT) n-1 obtained last time and the input rotation change rate (ΔNT) obtained this time are
NT) n is compared. Here, input rotation rate of change (Δ
NT) n-1 is smaller than the input rotation rate of change (ΔNT)n, that is, if the determination at step 5504 is negative, the routine exits from this routine. If it is positive, in the next step 5505, the current input rotation change rate (Δ
NT)n is substituted into the minimum rate of change ΔNTm1n.

Then, in the next step 5506, the minimum rate of change ΔNT
The value of m1n is the target input rotation rate of change ΔNil at this point.
On the other hand, it is determined whether the condition of 0.75ΔNil>ΔNTm1n is satisfied. If the determination here is negative, the routine exits, whereas if the determination is positive, the process advances to the next step 5507.

In this step, a predetermined amount α (for example, 4% thereof) is added to the correction amount ΔDa of the reference duty rate DU2 described above, and the correction amount ΔDa is updated.

After this, the next step 8508 is performed and the flag F
1 is set in LGL. In this way the flag FL
When GL is set to 1, the determination at step 5501 becomes positive in the next execution cycle, so the learning initial value calculation routine is not substantially executed thereafter.

The minimum value of the actual input rotation rate of change ΔNT during the period in which the first target rotation rate of change ΔNil is set is 0.75ΔNi
Being smaller than 1 means that the rise of the actual input rotational speed NT is small, and in such a case, the duty ratio is set to a large value to lower the oil pressure.

Also, input rotation speed NT is 1.45 No-ΔN2≦NT
If it is within the range that satisfies the condition of ≦1.45No, the determination in step $502 is negative, but step 5503
Since the determination is positive, step 5509 is executed in this case. In this step, the flag FLGFI is set to 1.
It is determined whether the flag FLGFI is set, and here, as explained in the flowchart of FIG. 6A, the flag FLGFI indicates that the target input rotation rate of change ΔNi is at the intermediate value carried out in step 5310 described above. It represents whether or not. Therefore, immediately after the input rotational speed NT reaches 1.45No-ΔN2, the determination in step 5509 becomes negative, so the process advances to step S510, and the process proceeds to step S551.
At step O, the timer TL is set, that is, its operation begins, time measurement is performed by the timer TL, and the values of the counter N and adder SUM are each set to 0.

After this, in the next execution cycle, the target input change rate ΔNi
is set to the above-mentioned intermediate value, and the flag flag FLGF
Since 1 is already set in I, step 5509
The determination is positive, and the next step 5511 is executed. In this step, the value of tie vTL is
(for example, 0.13 sec), but at this point, the determination is negative, so steps 5512 to 5514 are sequentially executed.

First, in step 5512, the value of the counter N is incremented by 1, and in step 8513, the value of the adder SUM is incremented by the current input rotation change rate ΔNT. Then, in the next step 8514, the average value XAV of the input rotation rate of change ΔNT is calculated from the values of the counter N and the adder SUM obtained in the previous step. That is, this average value XAV can be obtained from XAV=SUM+N.

Here, steps 5512 to 5514 are step 5
The process is repeated until the determination in step 511 becomes positive or the determination in step 5502 before that becomes positive. Therefore, as shown in FIG. 10, if the average value XAV calculated in step 5514 is measured by the timer TL until the predetermined time
This is the average value of the input rotation rate of change ΔNT during TL, and on the other hand, before the predetermined time
If the determination in 02 is positive, the time XTM during which the target input rotation rate of change ΔNi is maintained at ΔNi2
This is the average value of the input rotation rate of change ΔNT during the period.

Regardless of whether the determination at step 5502 or step 5511 is positive, step 5sis is executed next. In this step 5515, it is determined whether the average value XAY of the input rotation rate of change ΔNT that has already been determined is larger than 1.4ΔNi2.

Here, ΔNi2 is the target input rotation rate of change at that point.

If the determination in step 5515 is positive, that is,
If the average value XAV is sufficiently larger than the target input rotation rate of change ΔNi2, the process advances to step 8516, where it is determined whether the flag PLGD2 is set to 1. Here, this flag FLG
As clarified in the explanation of the duty rate calculation routine mentioned above, D2 is the duty rate calculated by a predetermined amount ΔD.
It shows whether only 4 is added or not. Therefore, if the determination in step 5516 is negative, the duty rate is controlled by feedback control of Ll in FIG. , a predetermined amount α is subtracted from the correction amount ΔDa. That is, in this case, the average value XAV of the input rotation rate of change ΔNT is sufficiently larger than the target input rotation rate of change ΔNi2 at that time, and the compensation of the predetermined amount ΔD4 is not added to the duty rate. Therefore, the correction amount ΔDa is corrected to decrease its value.

On the other hand, if the determination in step 5516 is positive, the process advances to step 8518, where the correction amount ΔDa
, a predetermined amount α is added to that value. In this case, even if the average value XAV is sufficiently larger than the target input rotation rate of change ΔNi2 at that point, the duty rate is controlled by the feedback control of L2 in FIG. Since we are in a situation where ΔD4 has been added, the correction amount ΔDa will be corrected to increase its value.

On the other hand, if the determination in step 5515 is negative, the process proceeds to step 5519, where the input rotation rate of change ΔN
It is determined whether the average value XAV of T is larger than 1.0ΔNi2. If the determination in step 5519 is negative, the average value XAV is the target input rotation rate of change ΔNi2
It is determined that the value is too small for the
8, the correction amount ΔDa is corrected to increase its value. On the other hand, if the determination in step 3519 is positive, the average value XAV is the target input rotation rate of change ΔNi
Assuming that the value is appropriate for 2, the process proceeds to step 5520, where the flag FLGL is set to 1. Incidentally, regardless of whether steps 851, 7, or 5518 described above are executed, the process reaches step S520, so that the flag FLGL is similarly set to 1 here.

When the flag FLGL is set to 1, step 550
1 is always positive, so at this point the learning initial value calculation routine ends and the correction amount ΔDa at this time is
That is, the duty rate D (D=DU2+ΔDa) at the time of starting the feedback control described above is stored and held.

According to the 3-2 shift down routine described above, after the input rotation speed NT of the input shaft 20 reaches 1.2NO, the duty rate is adjusted so that the actual input rotation change rate follows the target input rotation change rate ΔNi. As shown by the solid line in FIG. 13, after the feedback control starts, the torque fluctuation of the output shaft 50 is suppressed and the 3-2 shift operation is controlled. It turns out that it can be implemented. As a result, the shift shock during the 3-2 shift can be reduced and a smooth 3-2 shift can be performed. In Fig. 13, the broken line shows an example where the duty rate is controlled only by open loop control when performing a 3-2 shift. The torque fluctuation becomes large.

Further, in this invention, when starting the feedback control of the duty rate, the duty rate D1 at the time of starting, that is, DU2 + ΔDa, is determined by the correction amount ΔDa obtained by learning during the previous feedback control. Therefore, at the start of the next feedback control, the initial pressure of the hydraulic pressure PKD supplied to the first pressure chamber 81 of the kickdown servo 31 and determined by the duty rate becomes optimal. As a result, when performing feedback control, the gain can be made as small as possible.
Hunting does not occur in the duty rate, and torque fluctuations do not become large. Furthermore, hydraulic PKD
If the initial pressure is set optimally, the time required for the input rotation speed NT to reach its final target input rotation speed can be shortened, so that the 3-2 shift operation can be completed quickly.

Detection of input rotation speed NT In the shift control method of the present invention, as explained in the above-mentioned duty factor calculation routine, in order to accurately determine the duty factor, the input rotation speed NT of the input shaft 20 must be detected. Must be properly detected. however,
It is unavoidable that torsional vibrations occur in the input rotational speed NT of the input shaft 20, as shown by Z in FIG. 14, due to rotational fluctuations or rapid torque fluctuations of the engine 2 itself. Therefore, if the input rotation speed NT is read as is by the sensor and the input rotation change rate ΔNT is calculated from the read value of the input rotation speed NT, then this input rotation change rate ΔN
Since the value of T is affected by the above-mentioned torsional vibration,
As shown in FIG. 15, this results in an undesirably large fluctuation. Therefore, even if the duty rate is calculated based on the input rotation rate of change ΔNT with such fluctuations, the duty rate will deviate from the desired value, making it impossible to perform feedback control optimally. There is a possibility.

Therefore, in the present invention, when reading the input rotation speed NT in step S2 of the 3-2 shift down routine described above, the input rotation speed NT is averaged based on, for example, the following formula. That's what I do.

NT = (NTn+NTn-1) / 2 where, N
Tn-1 is the value detected in the previous execution cycle,
Further, NTn is a value detected in the current execution cycle.

If the input rotation speed NT is calculated by averaging it based on the above formula, even if the input rotation speed NT fluctuates due to torsional vibration, etc., it will be possible to average the input rotation speed NT. By calculating the input rotation change rate ΔNT based on the input rotation speed NT, the input rotation change rate ΔNT is smoothed as shown in FIG. Since the input rotation rate of change ΔNT smoothed in this way accurately reflects the actual input rotation rate of change, the duty rate can be appropriately controlled based on this input rotation rate of change ΔNT. As a result, the feedback control can be performed with high precision.

It goes without saying that the present invention is not limited to the above-described embodiment and can be modified in various ways. For example, the specific configuration of the automatic transmission, the specific numerical values described in the examples, etc. can be changed as appropriate.

(Effects of the Invention) As explained above, according to the speed change control method for a vehicle automatic transmission of the present invention, the friction engagement device In performing feedback control of the duty rate that determines the magnitude of the hydraulic pressure supplied to Since the input rotation change rate is calculated from the above, the input rotation change rate can be appropriately determined. Therefore, the duty rate determined based on the rate of change in input rotation becomes appropriate, so that it is possible to perform feedback control optimally.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic configuration diagram of a vehicle automatic transmission, FIG. 2 is a hydraulic circuit diagram around the kickdown servo and front clutch, and FIGS. 3A and 3B. 4A, 4B and 4C are flowcharts showing the open loop control routine, and FIG. 5 is a flowchart showing the stroke amount determination routine. FIG. 6B is a flowchart showing a feedback control routine; FIGS. 7A, 7B, and 7C are flowcharts showing a duty rate calculation routine;
8A, 8B, 8C, and 8D are flowcharts showing the learning initial value calculation routine; FIG. 9 is a graph of the 3-2 shift line determined by the vehicle speed and throttle valve opening; Figure 10 shows the duty rate versus time,
A graph showing changes in the input rotation speed and target input rotation rate of change, Figure 1L is a graph showing the relationship between duty rate and oil pressure, and Figure 12 shows the current input when calculating the duty rate correction amount. Figure 13 is a graph for explaining the rotational speed and duty rate, and Figure 1 is a graph showing changes in output shaft torque and duty rate with respect to time.
Figure 4 is a graph showing changes in input rotation speed over time.
FIG. 15 is a graph showing the fluctuation of the input rotation rate of change with respect to time when the input rotation speed is not smoothed, and FIG.
It is a graph showing the input rotation rate of change when the input rotation speed is smoothed and obtained. 24...Front clutch, 30...Kickdown brake, 31...Kickdown servo, 52...
Kickdown drum, 59... Piston, 65...
Electronic control device, 67... Solenoid valve, 79... Actuator rod, 8I... First pressure chamber, 93... Kick down switch. Applicant Mitsubishi Motors Corporation Agent Patent Attorney Kanji Nagato 2 Figure 3A Figure 3B Figure 4B Figure 5 Figure 6A Figure 6B Figure 8A Figure 8B Figure 9 Shin'i■ 11 Figure D 1 Ti car D ('/,) Figure 10 KL) Enter Tonoa 1n O-9/A)' 5 Hi Figure 13 Interrogation Figure 14 Time Figure 15 Time Figure 16 FF5 Darkness

Claims (1)

[Claims] Hydraulic operation that cooperates with a rotating element between an input shaft into which rotational force from the engine is input and an output shaft that outputs driving force to the driving wheels, and controls the rotation of the rotating element. By supplying a duty-controlled operating pressure to the friction engagement device and activating the friction engagement device, the rotation between the input shaft and the output shaft via the rotating element is provided. In a vehicle automatic transmission that performs a gear shifting operation, the rate of rotation change of the input shaft becomes the target rotational change from the point at which the input rotation speed of the input shaft reaches a predetermined value relative to the output rotation speed of the output shaft during the gear shifting operation. feedback control of the duty rate that determines the operating pressure to the frictional engagement device so as to follow the
During this feedback control, an average input rotation speed per unit time is determined from the detected input rotation speed, and a rotation change rate of the input shaft is calculated based on this average input rotation speed. Shift control method.