JP2003156136A - Control method for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method for an automatic transmission which smoothly changes over torque transmission from an disengagement side engagement element to an engagement side engagement element during power-on upshift, and improves a sense of deceleration during initial oil pressure output. SOLUTION: The control method for the automatic transmission carrying out the power-on upshift from a first speed stage to a second speed stage by disengaging a first engagement element and engaging a second engagement element has a process of reducing an oil pressure of the first engagement element and performing feedback control on the oil pressure of the first engagement element so that an input rotational frequency becomes a desired value a certain value higher than a rotational frequency NL in the first speed stage, and a process of feeding an offset oil pressure to the second engagement element for a predetermined time to provide an almost engagement starting state when the input rotational frequency becomes a value a predetermined value higher than the rotational frequency NL in the first speed state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for an automatic transmission, and more particularly to a control method for an engagement element during power-on upshift.

[0002]

2. Description of the Related Art Generally, an automatic transmission automatically determines a shift stage from a shift map according to operating conditions such as vehicle speed and throttle opening, and supplies or discharges hydraulic pressure to an engaging element to shift gears. . In such an automatic transmission, for example, when the vehicle is traveling at the second speed while depressing the accelerator pedal, the operating point determined by the vehicle speed and the throttle opening at that time crosses the upshift line of the shift map to the third speed. A so-called power-on upshift is performed in which the speed is changed.

At the time of power-on upshift, a so-called clutch-to-clutch is performed by releasing one engaging element and engaging another engaging element. In this case, in order to smoothly switch the torque transmission from the engagement element on the release side to the engagement element on the engagement side, the hydraulic pressure of the engagement element on the release side is reduced to reduce the input rotation speed at the low speed stage. The feedback control is performed so that it is higher by a certain value than the number, and while maintaining this feedback control, the input rotation speed is reduced by increasing the hydraulic pressure of the engaging element on the engagement side so that a smooth gear shift is performed. An automatic transmission has been proposed (Japanese Patent Publication No. 7-51984).

The above control has the effect of shortening the shift time and reducing the shift shock as compared with the prior art, but it is uncomfortable because the period of time during which the vehicle acceleration called the torque phase decreases is relatively long. There is a problem that a feeling of deceleration remains. Therefore, the applicant of the present application has proposed, as a control method in power-on upshift, a method capable of shortening the torque phase period and improving the feeling of deceleration (Japanese Patent Laid-Open No. 2001-2001).
No. 241543). This method reduces the hydraulic pressure of the disengagement side engagement element to perform feedback control so that the turbine speed becomes a target speed higher by a constant value r ₁ than the rotation speed N _L in the low speed stage, while the engagement side engagement is performed. The hydraulic pressure of the coupling element is increased to reduce the turbine rotation speed, the feedback target value is increased when the turbine rotation speed falls below the rotation speed N _L in the low speed stage, and the decompression gradient of the disengagement side engagement element is set to the previous value. It should be larger than the pressure reduction gradient.

FIG. 1 shows a specific control example at the time of power-on upshift using the above control method. The turbine rotation speed (input rotation speed) and the instruction of the solenoid valve for hydraulic control of the engagement side engagement element are shown. Time changes of the current, the command current of the solenoid valve for hydraulic pressure control of the disengagement side engagement element, and the hydraulic pressure of the engagement side engagement element are shown. The solenoid valve on the engagement side is a normally open type that supplies the maximum oil pressure to the engagement element when the instruction current is OFF, and the solenoid valve on the release side supplies the maximum oil pressure to the engagement element when the instruction current is ON. It is a normally closed type. Further, although the hydraulic pressure of the disengagement side engagement element is not shown in FIG. 1, it shows almost the same hydraulic pressure change as the current change of the disengagement side solenoid valve.

First, an upshift command to the high speed stage is issued.
Then, time t₁ Due to the looseness of the engaging elements on the engaging side,
The solenoid current is turned off for a fixed period. This rattling
Is the operation to fill the oil pressure in the oil supply path to the engaging element.
Is. After tattering, time t ₂ The solenoid current
The standby current is controlled to be slightly lower than the large value (ON), and the engaging side
Supply standby hydraulic pressure to the engagement element. This hydraulic pressure is
The gap between the piston of the coupling element and the clutch plate (invalid straw
Hydraulic pressure to eliminate the
This oil pressure causes the piston to contact the first clutch plate.
Move to near the state you want to. Time t₃ On the release side Solenoi
The command current of the valve is slightly lowered to reduce the hydraulic pressure of the disengagement side engagement element.
Then, the turbine speed is N in the low speed stage._L One more
Fixed value r₁ Feedback system so that the target value will be as high as possible
Start. Turbine rotation speed rises by a predetermined amount
When it is detected that time t_Four Initially on the engaging side engaging element
To supply hydraulic pressure, set the engagement side solenoid current to a constant value.
Lower with. The initial oil pressure is the gradient of the turbine speed
The transmission torque of the engaging element is reduced so that
Is the hydraulic pressure that generates By supplying the initial hydraulic pressure, time
t_Five And turbine speed is low speed N_L Descend to
Then, it is determined that the torque phase has started, and the torque phase
Feedback target value
It is higher than the standard value and the disengagement side engagement element is reduced in the torque phase.
Make the pressure gradient greater than the previous decompression gradient. Time t₆ 
And turbine speed is low speed N_L More predetermined amount r₂ 
When only lowered, the hydraulic feed back of the disengagement side engagement element
End the initial control and release it.
Finished, so that the turbine speed drops at a predetermined slope
Feedback control of the engagement side solenoid current is performed. Furthermore
The turbine speed and the high speed N_H Is constant
When it is detected that the value is below the specified value (synchronization detection), the engaging side
The current of the solenoid is dropped at a constant gradient, and at time t₇ In charge
The mating side engagement element is completely engaged, and the shift is completed.

[0007]

According to the above method,
It is possible to smoothly transfer the torque from the engagement element on the release side to the engagement element on the engagement side, shorten the period of the torque phase, and improve the feeling of deceleration. However, when the turbine rotational speed rises above the rotational speed N _L in the low speed stage by a predetermined value, the initial hydraulic pressure is supplied to the engagement-side engaging element, so that the hydraulic pressure temporarily increases rapidly as indicated by the broken line. The mating engagement element may suddenly engage. Such sudden engagement is affected by variations in hydraulic pressure, temperature, response delay of the hydraulic circuit, and the like. However, if the engagement-side engagement element suddenly engages before the hydraulic pressure of the disengagement-side engagement element decreases, there is a problem that a so-called double clutch state occurs and a deceleration feeling (shift shock) occurs in the vehicle.

Therefore, an object of the present invention is to smoothly switch the torque transmission from the engagement element on the release side to the engagement element on the engagement side at the time of power-on upshift, and to output the initial hydraulic pressure. An object of the present invention is to provide a control method for an automatic transmission that can improve the feeling of deceleration during time.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 is to release the first engaging element and to engage the second engaging element. 1
In the control method of the automatic transmission for performing the power-on upshift from the shift stage to the second shift stage, the hydraulic pressure of the first engagement element is reduced and the input rotation speed is the rotation speed N at the first shift speed. First to set the target value higher than _L by a certain value
Feedback control of the hydraulic pressure of the engagement element, and when the input rotation speed becomes a value higher than the rotation speed N _L in the first gear stage by a predetermined value, the second engagement element is substantially in the engagement start state. And a step of supplying the offset hydraulic pressure for a predetermined time, and after the offset hydraulic pressure is supplied, the input engaging speed is higher than the offset hydraulic pressure for the second engagement element so that the input rotational speed is reduced to the rotational speed N _L or less in the first gear stage. The initial hydraulic pressure is supplied, and the second
Generating a predetermined transmission torque in the engaging element, and terminating the feedback control of the first engaging element when the input rotational speed is lower than the rotational speed N _L in the first gear by a predetermined value. A method for controlling an automatic transmission is provided.

FIG. 2 shows an example of the control method according to the present invention. FIG. 2 shows the control method in FIG. 1 with control by offset hydraulic pressure added, and is the same as FIG. 1 except for the supply of offset hydraulic pressure. When the input rotation speed (turbine rotation speed) becomes higher than the rotation speed N _L in the first gear stage by a predetermined value (time t ₄ ), conventionally, the timing is to output the initial hydraulic pressure. In the invention, the hydraulic pressure (offset hydraulic pressure) that is one step lower than the initial hydraulic pressure is supplied to bring the engagement-side engagement element into the substantially engagement start state. When the offset hydraulic pressure is output, the engaging side engaging element may be in a state immediately before the start of engagement or may be in a slightly engaged state due to variations in hydraulic pressure, temperature, response delay of the hydraulic circuit, and the like. is there. However, the sudden rise of the hydraulic pressure that occurs when the initial hydraulic pressure is output all at once is eliminated, and deceleration feeling (shift shock) hardly occurs. If the initial hydraulic pressure is output at time t ₈ after the offset hydraulic pressure has been output for a predetermined period of time, a transmission torque is generated in the engagement-side engaging element, but the difference between the offset hydraulic pressure and the initial hydraulic pressure is relatively small. The shock is small.
Therefore, smooth gear shifting can be realized. In the present invention, the offset hydraulic pressure is a hydraulic pressure that makes the engagement element almost in the engagement start state. , Just before the transmission torque is generated. However, transmission torque may be generated or may not be generated due to variations in hydraulic pressure.

In the present invention, the hydraulic pressure to the engagement element is regulated by the solenoid valve. The pressure regulating method may be an indirect control method in which the hydraulic pressure of the engaging element is controlled by a control valve and the control valve is controlled by a signal hydraulic pressure regulated by a solenoid valve, or the hydraulic pressure of the engaging element is controlled by a solenoid. A direct control method in which the valve is directly controlled may be used. The present invention is more effective because the indirect control tends to delay the hydraulic response than the direct control.

After the offset hydraulic pressure is supplied, when the initial hydraulic pressure is output at time t ₈ , a temporary increase in hydraulic pressure (hereinafter referred to as hydraulic hump) may occur. This hydraulic hump is generated because the hydraulic pressure changes in the oil passage before and after the contact point between the clutch plate of the engagement element and the piston due to the supply of the initial hydraulic pressure. In particular, the hydraulic circuit does not supply hydraulic pressure from the solenoid valve to the engaging element,
This is likely to occur when the hydraulic circuit has poor responsiveness, such as a system in which hydraulic pressure is supplied from a solenoid valve to an engaging element via a control valve. Further, the hydraulic hump increases as the step difference between the offset hydraulic pressure and the initial hydraulic pressure increases.
When such a hydraulic hump occurs, the engagement element on the engagement side engages before the engagement element on the release side disengages, which may cause a feeling of deceleration of the vehicle (shift shock). In order to reduce the hydraulic hump as described above, it is effective to increase the offset hydraulic pressure and reduce the step difference from the initial hydraulic pressure. The heights of the initial hydraulic pressure and the offset hydraulic pressure differ depending on the hydraulic circuit. For example, when the standby hydraulic pressure immediately before outputting the initial hydraulic pressure is 20% of the maximum pressure (line pressure) and the initial hydraulic pressure is 60%, the offset hydraulic pressure is It is preferably 40% or more.

When the control method disclosed in Japanese Patent Laid-Open No. 2001-241543 is applied to the method of supplying the offset hydraulic pressure before the initial hydraulic pressure as in the present invention, the following problems may occur. . That is, in order to reduce the hydraulic hump as described above, it is effective to increase the offset hydraulic pressure and reduce the step from the initial hydraulic pressure. However, when the offset hydraulic pressure is increased, the offset hydraulic pressure is increased as shown by the broken line in FIG. During the hydraulic pressure supply period, the turbine speed may decrease to the low speed stage speed N _L. This is erroneously detected as the start of the torque phase, and the feedback target value of the disengagement-side engagement element is increased to reduce the pressure reduction even though the engagement-side engagement element does not have sufficient transmission torque. If the gradient is increased, there is a possibility that a problem such as a sudden rise in engine rotation may occur. Therefore, in claim 2, when the input rotation speed falls below the rotation speed N _L in the first speed stage during the supply period of the offset hydraulic pressure, the feedback control of the first engagement element (disengagement side engagement element) is performed. The feedback gain after N _L detection is made larger than the feedback gain during the period from the start to the N _L detection, while the input rotation speed during the supply period of the initial hydraulic pressure is less than or equal to the rotation speed N _L in the first gear stage. When it decreases to, the feedback target value after N _L detection is made higher than the feedback target value in the period from the feedback control start of the first engagement element to the N _L detection. Thus, even if N _L is detected during the supply period of the offset hydraulic pressure, the disengagement side engagement element continues the feedback control to prevent the engine rotation from rising and to increase the feedback gain. By increasing the hydraulic pressure followability, it is possible to prevent a feeling of deceleration due to the double clutch between the engagement element on the engagement side and the engagement element on the release side. Further, when the input rotation speed falls below the rotation speed N _L in the first gear stage during the supply period of the initial hydraulic pressure, the feedback target value is set high as in Japanese Patent Laid-Open No. 2001-241543. The torque phase period can be shortened to improve the feeling of deceleration.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows a vehicle system equipped with an automatic transmission for a vehicle according to the present invention. The output of the engine 1 is transmitted to the speed change mechanism 4 via the torque converter 3 of the automatic transmission 2, and the speed change mechanism 4 is connected to wheels (not shown) via the output shaft 5. The automatic transmission 2 includes an oil pump 6 driven by the engine 1 via a torque converter 3, and the discharge pressure of the oil pump 6 is sent to a hydraulic control device 7. The hydraulic control device 7 is provided with first to third solenoid valves 21 to 23 for gear shift control. By controlling these solenoid valves 21 to 23 with the AT controller 20, various hydraulic valves incorporated in the gear shift mechanism 4 are controlled. The hydraulic pressure of the coupling element is controlled according to the traveling state. Here, signals such as engine speed, throttle opening, turbine speed, vehicle speed, and shift position are input to the AT controller 20, but other signals (ATF oil temperature, etc.) may be input. In the hydraulic control device 7, three shift control solenoid valves 2 are used.
Although the example using 1 to 23 is shown, two or less or four or more solenoid valves may be used, and solenoid valves for lock-up clutch control, line pressure control, etc. in addition to gear shift control may be used. It may be provided.

FIG. 4 shows an example of the speed change mechanism 4. The speed change mechanism 4 includes an input shaft 10 to which engine power is transmitted via the torque converter 3 and three clutches C1 which are engagement elements.
-C3 and two brakes B1, B2, one-way clutch F, Ravigneaux type planetary gear mechanism 11, differential device 1
4 and so on.

Forward sun gear 1 of the planetary gear mechanism 11
1a and the input shaft 10 are connected via a C1 clutch, and the rear sun gear 11b and the input shaft 10 are connected via a C2 clutch. The carrier 11c is connected to the center shaft 15, and the center shaft 15 is C3.
It is connected to the input shaft 10 via a clutch. Also,
The carrier 11c is connected to the transmission case 16 via a B2 brake and a one-way clutch F that allows only the normal rotation (engine rotation direction) of the carrier 11c. The carrier 11c supports two types of pinion gears 11d and 11e, the forward sun gear 11a meshes with a long pinion 11d having a long axial length, and the rear sun gear 11b.
Engages with the long pinion 11d via the short pinion 11e having a short axial length. Long pinion 11d
A ring gear 11f that meshes with the chisel is coupled to the output gear 12. The output gear 12 is connected to the differential gear 14 via an intermediate shaft 13.

The transmission mechanism 4 includes clutches C1, C2 and C.
3, the operation of the brakes B1 and B2 and the one-way clutch F realizes four forward gears and one reverse gear as shown in FIG. In FIG. 5, the black circle indicates the hydraulic operating state. The B2 brake is engaged at the time of reverse and at the first speed in the L range. Further, FIG. 5 also shows the operating states of the first to third solenoid valves (SOL1 to SOL3) 21 to 23. ◯ indicates an energized state, and × indicates a non-energized state. Note that this operation table shows the operation in the steady state.

The first solenoid valve 21 is for B1 brake control, the second solenoid valve 22 is for C2 clutch control, and the third solenoid valve 23 is both for C3 clutch control and B2 brake control. Third
The reason why the solenoid valve 23 is used for both C3 clutch control and B2 brake control is that the B2 brake does not operate in the D range and is used only in the L range engine brake control and the R range transient control. This is because it does not interfere with the C3 clutch operated by. Since the first to third solenoid valves 21 to 23 need to perform delicate hydraulic pressure control, duty solenoid valves or linear solenoid valves are used. Further, in this embodiment, the first solenoid valve 21 is of the normally closed type and the second and third solenoid valves 22 and 23 are of the normally open type.

FIG. 6 shows an example of a hydraulic control device for a C3 clutch which is an engagement element on the engagement side according to the present invention. The C3 pressure control valve 30 is a valve for controlling the hydraulic pressure P _{C3 of the} C3 clutch, and includes a spool 31 biased to the left by a spring 32. The signal port 33 is connected to the third solenoid valve 23 and receives the solenoid pressure P _s3 . At the 1st and 2nd speeds in the D range, the solenoid valve 23 is ON, so the solenoid pressure P _s3
And the spool 31 is in the upper position in FIG. Further, the solenoid valve 23 is OF in the 3rd and 4th speeds.
_Therefore , the solenoid pressure P _s3 is generated and the spool 31
Is the lower position in FIG. The port 34 is a drain port, the port 35 is an output port connected to the C3 clutch, and the port 36 is an input port to which the line pressure is input. The output pressure P _C3 is fed back through the inside of the spool 31 to the right end port 37 where the spring 32 is arranged. Therefore, the output pressure P _C3 is proportionally controlled by the solenoid pressure P _s3 .

FIG. 7 shows an example of the hydraulic control device for the B1 brake, which is the disengagement side engagement element according to the present invention. The B1 pressure control valve 30 is a valve for controlling the hydraulic pressure P _{B1 of the} B1 brake, and includes a spool 42 biased to the left by a spring 41. The signal port 43 is connected to the first solenoid valve 21, and the solenoid pressure P _S1 is input. At the 1st and 3rd speeds in the D range, the solenoid valve 21 is OFF, so the solenoid pressure P
_S1 is drained and spool 42 is in the upper position of FIG. Also, the solenoid valve 21 is turned on in the 2nd and 4th speeds.
_Therefore , the solenoid pressure P _s1 is generated, and the spool 42 is at the lower position in FIG. 7. Port 44 is a drain port,
Port 45 is an output port connected to the B ₁ brake, and port 46 is an input port to which the line pressure is input. The output pressure P _B1 is applied to the right end port 47 where the spring 41 is arranged.
Is fed back through the inside of the spool 42. Therefore, the output pressure P _B1 is proportionally controlled by the solenoid pressure P _s1 .

FIG. 8 shows an example of the shift map of the D range stored in the memory of the AT controller 20. In FIG. 8, solid lines represent upshift lines and broken lines represent downshift lines.

Next, the flow of the shift control when performing the power-on upshift from the second speed to the third speed will be described with reference to FIG. First, when the control is started, it is determined whether or not the on-up shift from the second speed to the third speed is started (step S
1). Here, in the power-on state, it is judged whether or not the upshift line of the second speed → the third speed is crossed.

When it is determined that the on-up shift is to be started, first, the engagement side engagement element C3 is loosened (step S2) and the standby hydraulic pressure is output (step S3). At the same time, the instruction current of the disengagement side engagement element B1 is also reduced to the value immediately before the occurrence of slip. Further, the command current of the disengagement side solenoid is further lowered slightly (step S4), and the hydraulic pressure of the disengagement side engagement element B1 is reduced. As a result, the turbine rotation speed rises, so it is determined whether or not a predetermined amount has risen (step S5). When the turbine rotation blows up by a predetermined amount, the offset hydraulic pressure is output to the engagement side engagement element C3 for a predetermined period (step S6), and the feedback control of the disengagement side engagement element B1 is started (step S).
7). The offset hydraulic pressure is preferably a hydraulic pressure that does not cause a hydraulic bump (see FIG. 2) when the initial hydraulic pressure is output thereafter.

Next, the rotational speed N when the turbine rotational speed is 2nd speed.
_It is judged whether or not it becomes _L or less (step S8), N
If it becomes _L or less, the feedback gain is increased (step S9). As described above, even if N _L is detected during the supply period of the offset hydraulic pressure, the disengagement side engagement element B1 continues the feedback control to prevent the engine speed from rising, and compare with that before the N _L detection. By increasing the feedback gain after detection of N _L to improve the hydraulic pressure followability, the pressure reducing gradient of the disengagement side engaging element B1 is made larger than the pressure reducing gradient before that, and the engaging side engaging element C
The double clutch between 3 and the disengagement side engaging element B1 prevents the feeling of deceleration.

On the other hand, when the turbine speed does not _fall below N _L during the supply of the offset hydraulic pressure, the initial hydraulic pressure is output to the engagement side engagement element C3 (step S1).
0). Then, it is determined whether or not the turbine rotation speed has become equal to or lower than the rotation speed N _L (step S11), and if it has become equal to or lower than N _L , the feedback target value is increased (step S12). That is, it is determined that the torque phase has started, the feedback target value in the torque phase is made higher than the feedback target value before the torque phase, and the pressure reduction gradient of the disengagement side engagement element B1 in the torque phase is made larger than the pressure reduction gradient before that. To do. In this way, the torque phase period can be shortened and the feeling of deceleration can be improved.

Next, the rotational speed N when the turbine rotational speed is 2nd speed.
_When it becomes lower than _L by a predetermined value r ₂ (step S
13) Then, the feedback control of the disengagement side engagement element B1 is terminated, the period of the initial hydraulic pressure of the engagement side engagement element C3 is terminated, and the feedback control is started so that the turbine rotation speed decreases at a predetermined gradient. (Step S14).
Then, when it is detected that the difference between the turbine rotation speed and the rotation speed N _H of the third speed is equal to or less than a certain value (synchronization determination: step S15), the engagement side engagement element C3 is fastened, and
The disengagement side engagement element B1 is disengaged (step S16), and the control ends.

In the above embodiment, the rattling hydraulic pressure and the standby hydraulic pressure are output before the offset hydraulic pressure is output, but the present invention is not limited to this. For example, the offset hydraulic pressure may be output after the rattling hydraulic pressure, or the offset hydraulic pressure may be output after the standby hydraulic pressure is output without the rattling hydraulic pressure. Furthermore, in order to eliminate the invalid stroke, a hydraulic pressure different from the rattling hydraulic pressure and the standby hydraulic pressure may be supplied. In the above embodiment, 2
The on-up shifting from the third speed to the third speed, that is, the control in the case of engaging the C3 clutch and releasing the B1 brake has been described, but the same can be applied to the control of the engagement element in other on-up shifting. For example, at the time of on-up from the 3rd speed to the 4th speed, the C2 clutch is the disengagement side engagement element and the B1 brake is the engagement side engagement element. The automatic transmission of the present invention has three clutches C as shown in FIG.
It is not limited to the automatic transmission having 1 to C3 and the two brakes B1 and B2.

[0028]

As is apparent from the above description, according to the present invention, during the power-on upshift, the input rotation speed becomes a value higher than the rotation speed N _L in the first gear by a predetermined value. At this time, the offset hydraulic pressure that is one step lower than the initial hydraulic pressure is supplied, and the engagement side engagement elements are almost in the engagement start state, so the sudden rise of the hydraulic pressure that occurs when the initial hydraulic pressure is output all at once is eliminated, and deceleration is reduced. Feeling (shift shock) can be prevented. Also, after outputting the offset hydraulic pressure for a predetermined period,
When the initial hydraulic pressure is output, a transmission torque is generated in the engagement-side engagement element, but since the step difference between the offset hydraulic pressure and the initial hydraulic pressure is relatively small, almost no shock occurs. Therefore, smooth gear shifting can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of conventional shift control at power-on-up.

FIG. 2 is a time change diagram of a turbine speed, an instruction current of an engagement side solenoid, an instruction current of a release side solenoid, and an engagement element hydraulic pressure in an example of a control method according to the present invention.

FIG. 3 is a system diagram in which the vehicle automatic transmission according to the invention is mounted.

FIG. 4 is a skeleton diagram of a transmission mechanism of the automatic transmission shown in FIG.

5 is an operation table of each engagement element and solenoid valve of the transmission mechanism shown in FIG.

FIG. 6 is a hydraulic circuit diagram of a C3 clutch.

FIG. 7 is a hydraulic circuit diagram of a B1 brake.

8 is an example of a shift diagram of the automatic transmission of FIG.

FIG. 9 is a flowchart of an example of a control method according to the present invention.

[Explanation of symbols]

C3 engagement side engagement element B1 release side engagement element 20 AT controller 21 (SOL1) B ₁ brake control solenoid valve 23 (SOL3) C3 clutch control solenoid valve 30 C3 pressure control valve 40 B1 pressure control valve

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Claims (2)

[Claims] 1. A first engagement element is released and a second engagement element is released.
By engaging the engaging element, the first gear shifts to the second gear.
Automatic transmission that performs power-on upshift to the next gear
In the control method of No. 1, the hydraulic pressure of the first engagement element is reduced.
And the input rotation speed is the rotation speed N at the first gear stage. _L Than
The oil of the first engagement element is adjusted so that the target value becomes higher by a fixed value.
The process of feedback control of pressure and the input speed is the first
Number of revolutions N_L Higher than the specified value
When it is turned off, the second engagement element is almost in the engagement start state.
Offset process of supplying set hydraulic pressure for a predetermined time and offset
After the hydraulic pressure is supplied, the input rotation speed is the rotation speed at the first speed stage.
Number N_L Offset the second engaging element so that
The initial hydraulic pressure higher than the hydraulic pressure is supplied to the second engaging element.
The process of generating a constant transmission torque and the input speed is the first
Number of revolutions N_L When it falls by a predetermined value
To terminate the feedback control of the first engagement element
A method for controlling an automatic transmission, comprising: 2. When the input rotational speed falls below the rotational speed N _{L at} the first gear stage during the supply of the offset hydraulic pressure, from the start of feedback control of the first engagement element to the detection of N _L. The feedback gain after detection of N _L is increased as compared with the feedback gain of the period, and when the input rotation speed falls below the rotation speed N _L in the first gear stage during the supply period of the initial hydraulic pressure, 2. The control of the automatic transmission according to claim 1, wherein the feedback target value after the N _L detection is made higher than the feedback target value during the period from the feedback control start of the engagement element to the N _L detection. Method.